udp.c source code [Linux/net/ipv4/udp.c]

1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* INET An implementation of the TCP/IP protocol suite for the LINUX
4	* operating system. INET is implemented using the BSD Socket
5	* interface as the means of communication with the user level.
6	*
7	* The User Datagram Protocol (UDP).
8	*
9	* Authors: Ross Biro
10	* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11	* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
12	* Alan Cox, <alan@lxorguk.ukuu.org.uk>
13	* Hirokazu Takahashi, <taka@valinux.co.jp>
14	*
15	* Fixes:
16	* Alan Cox : verify_area() calls
17	* Alan Cox : stopped close while in use off icmp
18	* messages. Not a fix but a botch that
19	* for udp at least is 'valid'.
20	* Alan Cox : Fixed icmp handling properly
21	* Alan Cox : Correct error for oversized datagrams
22	* Alan Cox : Tidied select() semantics.
23	* Alan Cox : udp_err() fixed properly, also now
24	* select and read wake correctly on errors
25	* Alan Cox : udp_send verify_area moved to avoid mem leak
26	* Alan Cox : UDP can count its memory
27	* Alan Cox : send to an unknown connection causes
28	* an ECONNREFUSED off the icmp, but
29	* does NOT close.
30	* Alan Cox : Switched to new sk_buff handlers. No more backlog!
31	* Alan Cox : Using generic datagram code. Even smaller and the PEEK
32	* bug no longer crashes it.
33	* Fred Van Kempen : Net2e support for sk->broadcast.
34	* Alan Cox : Uses skb_free_datagram
35	* Alan Cox : Added get/set sockopt support.
36	* Alan Cox : Broadcasting without option set returns EACCES.
37	* Alan Cox : No wakeup calls. Instead we now use the callbacks.
38	* Alan Cox : Use ip_tos and ip_ttl
39	* Alan Cox : SNMP Mibs
40	* Alan Cox : MSG_DONTROUTE, and 0.0.0.0 support.
41	* Matt Dillon : UDP length checks.
42	* Alan Cox : Smarter af_inet used properly.
43	* Alan Cox : Use new kernel side addressing.
44	* Alan Cox : Incorrect return on truncated datagram receive.
45	* Arnt Gulbrandsen : New udp_send and stuff
46	* Alan Cox : Cache last socket
47	* Alan Cox : Route cache
48	* Jon Peatfield : Minor efficiency fix to sendto().
49	* Mike Shaver : RFC1122 checks.
50	* Alan Cox : Nonblocking error fix.
51	* Willy Konynenberg : Transparent proxying support.
52	* Mike McLagan : Routing by source
53	* David S. Miller : New socket lookup architecture.
54	* Last socket cache retained as it
55	* does have a high hit rate.
56	* Olaf Kirch : Don't linearise iovec on sendmsg.
57	* Andi Kleen : Some cleanups, cache destination entry
58	* for connect.
59	* Vitaly E. Lavrov : Transparent proxy revived after year coma.
60	* Melvin Smith : Check msg_name not msg_namelen in sendto(),
61	* return ENOTCONN for unconnected sockets (POSIX)
62	* Janos Farkas : don't deliver multi/broadcasts to a different
63	* bound-to-device socket
64	* Hirokazu Takahashi : HW checksumming for outgoing UDP
65	* datagrams.
66	* Hirokazu Takahashi : sendfile() on UDP works now.
67	* Arnaldo C. Melo : convert /proc/net/udp to seq_file
68	* YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
69	* Alexey Kuznetsov: allow both IPv4 and IPv6 sockets to bind
70	* a single port at the same time.
71	* Derek Atkins <derek@ihtfp.com>: Add Encapsulation Support
72	* James Chapman : Add L2TP encapsulation type.
73	*/
74
75	#define pr_fmt(fmt) "UDP: " fmt
76
77	#include <linux/bpf-cgroup.h>
78	#include <linux/uaccess.h>
79	#include <asm/ioctls.h>
80	#include <linux/memblock.h>
81	#include <linux/highmem.h>
82	#include <linux/types.h>
83	#include <linux/fcntl.h>
84	#include <linux/module.h>
85	#include <linux/socket.h>
86	#include <linux/sockios.h>
87	#include <linux/igmp.h>
88	#include <linux/inetdevice.h>
89	#include <linux/in.h>
90	#include <linux/errno.h>
91	#include <linux/timer.h>
92	#include <linux/mm.h>
93	#include <linux/inet.h>
94	#include <linux/netdevice.h>
95	#include <linux/slab.h>
96	#include <linux/sock_diag.h>
97	#include <net/tcp_states.h>
98	#include <linux/skbuff.h>
99	#include <linux/proc_fs.h>
100	#include <linux/seq_file.h>
101	#include <net/net_namespace.h>
102	#include <net/icmp.h>
103	#include <net/inet_hashtables.h>
104	#include <net/ip.h>
105	#include <net/ip_tunnels.h>
106	#include <net/route.h>
107	#include <net/checksum.h>
108	#include <net/gso.h>
109	#include <net/xfrm.h>
110	#include <trace/events/udp.h>
111	#include <linux/static_key.h>
112	#include <linux/btf_ids.h>
113	#include <trace/events/skb.h>
114	#include <net/busy_poll.h>
115	#include "udp_impl.h"
116	#include <net/sock_reuseport.h>
117	#include <net/addrconf.h>
118	#include <net/udp_tunnel.h>
119	#include <net/gro.h>
120	#if IS_ENABLED(CONFIG_IPV6)
121	#include <net/ipv6_stubs.h>
122	#endif
123	#include <net/rps.h>
124
125	struct udp_table udp_table __read_mostly;
126
127	long sysctl_udp_mem[`3`] __read_mostly;
128	EXPORT_IPV6_MOD(sysctl_udp_mem);
129
130	DEFINE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
131	EXPORT_PER_CPU_SYMBOL_GPL(udp_memory_per_cpu_fw_alloc);
132
133	#define MAX_UDP_PORTS 65536
134	#define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN_PERNET)
135
136	static struct udp_table udp_get_table_prot(struct* sock *sk)
137	{
138	return sk->sk_prot->h.udp_table ? : sock_net(sk)->ipv4.udp_table;
139	}
140
141	static int udp_lib_lport_inuse(struct net *net, __u16 num,
142	const struct udp_hslot *hslot,
143	unsigned long *bitmap,
144	struct sock sk, unsigned* int log)
145	{
146	kuid_t uid = sk_uid(sk);
147	struct sock *sk2;
148
149	sk_for_each(sk2, &hslot->head) {
150	if (net_eq(net1: sock_net(sk: sk2), net2: net) &&
151	sk2 != sk &&
152	(bitmap \|\| udp_sk(sk2)->udp_port_hash == num) &&
153	(!sk2->sk_reuse \|\| !sk->sk_reuse) &&
154	(!sk2->sk_bound_dev_if \|\| !sk->sk_bound_dev_if \|\|
155	sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
156	inet_rcv_saddr_equal(sk, sk2, match_wildcard: true)) {
157	if (sk2->sk_reuseport && sk->sk_reuseport &&
158	!rcu_access_pointer(sk->sk_reuseport_cb) &&
159	uid_eq(left: uid, right: sk_uid(sk: sk2))) {
160	if (!bitmap)
161	return `0`;
162	} else {
163	if (!bitmap)
164	return `1`;
165	__set_bit(udp_sk(sk2)->udp_port_hash >> log,
166	bitmap);
167	}
168	}
169	}
170	return `0`;
171	}
172
173	/*
174	* Note: we still hold spinlock of primary hash chain, so no other writer
175	* can insert/delete a socket with local_port == num
176	*/
177	static int udp_lib_lport_inuse2(struct net *net, __u16 num,
178	struct udp_hslot *hslot2,
179	struct sock *sk)
180	{
181	kuid_t uid = sk_uid(sk);
182	struct sock *sk2;
183	int res = `0`;
184
185	spin_lock(lock: &hslot2->lock);
186	udp_portaddr_for_each_entry(sk2, &hslot2->head) {
187	if (net_eq(net1: sock_net(sk: sk2), net2: net) &&
188	sk2 != sk &&
189	(udp_sk(sk2)->udp_port_hash == num) &&
190	(!sk2->sk_reuse \|\| !sk->sk_reuse) &&
191	(!sk2->sk_bound_dev_if \|\| !sk->sk_bound_dev_if \|\|
192	sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
193	inet_rcv_saddr_equal(sk, sk2, match_wildcard: true)) {
194	if (sk2->sk_reuseport && sk->sk_reuseport &&
195	!rcu_access_pointer(sk->sk_reuseport_cb) &&
196	uid_eq(left: uid, right: sk_uid(sk: sk2))) {
197	res = `0`;
198	} else {
199	res = `1`;
200	}
201	break;
202	}
203	}
204	spin_unlock(lock: &hslot2->lock);
205	return res;
206	}
207
208	static int udp_reuseport_add_sock(struct sock sk, struct* udp_hslot *hslot)
209	{
210	struct net *net = sock_net(sk);
211	kuid_t uid = sk_uid(sk);
212	struct sock *sk2;
213
214	sk_for_each(sk2, &hslot->head) {
215	if (net_eq(net1: sock_net(sk: sk2), net2: net) &&
216	sk2 != sk &&
217	sk2->sk_family == sk->sk_family &&
218	ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
219	(udp_sk(sk2)->udp_port_hash == udp_sk(sk)->udp_port_hash) &&
220	(sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
221	sk2->sk_reuseport && uid_eq(left: uid, right: sk_uid(sk: sk2)) &&
222	inet_rcv_saddr_equal(sk, sk2, match_wildcard: false)) {
223	return reuseport_add_sock(sk, sk2,
224	bind_inany: inet_rcv_saddr_any(sk));
225	}
226	}
227
228	return reuseport_alloc(sk, bind_inany: inet_rcv_saddr_any(sk));
229	}
230
231	/**
232	* udp_lib_get_port - UDP/-Lite port lookup for IPv4 and IPv6
233	*
234	* @sk: socket struct in question
235	* @snum: port number to look up
236	* @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
237	* with NULL address
238	*/
239	int udp_lib_get_port(struct sock sk, unsigned* short snum,
240	unsigned int hash2_nulladdr)
241	{
242	struct udp_table *udptable = udp_get_table_prot(sk);
243	struct udp_hslot hslot, hslot2;
244	struct net *net = sock_net(sk);
245	int error = -EADDRINUSE;
246
247	if (!snum) {
248	DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
249	unsigned short first, last;
250	int low, high, remaining;
251	unsigned int rand;
252
253	inet_sk_get_local_port_range(sk, low: &low, high: &high);
254	remaining = (high - low) + `1`;
255
256	rand = get_random_u32();
257	first = reciprocal_scale(val: rand, ep_ro: remaining) + low;
258	/*
259	* force rand to be an odd multiple of UDP_HTABLE_SIZE
260	*/
261	rand = (rand \| `1`) * (udptable->mask + `1`);
262	last = first + udptable->mask + `1`;
263	do {
264	hslot = udp_hashslot(table: udptable, net, num: first);
265	bitmap_zero(dst: bitmap, PORTS_PER_CHAIN);
266	spin_lock_bh(lock: &hslot->lock);
267	udp_lib_lport_inuse(net, num: snum, hslot, bitmap, sk,
268	log: udptable->log);
269
270	snum = first;
271	/*
272	* Iterate on all possible values of snum for this hash.
273	* Using steps of an odd multiple of UDP_HTABLE_SIZE
274	* give us randomization and full range coverage.
275	*/
276	do {
277	if (low <= snum && snum <= high &&
278	!test_bit(snum >> udptable->log, bitmap) &&
279	!inet_is_local_reserved_port(net, port: snum))
280	goto found;
281	snum += rand;
282	} while (snum != first);
283	spin_unlock_bh(lock: &hslot->lock);
284	cond_resched();
285	} while (++first != last);
286	goto fail;
287	} else {
288	hslot = udp_hashslot(table: udptable, net, num: snum);
289	spin_lock_bh(lock: &hslot->lock);
290	if (hslot->count > `10`) {
291	int exist;
292	unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
293
294	slot2 &= udptable->mask;
295	hash2_nulladdr &= udptable->mask;
296
297	hslot2 = udp_hashslot2(table: udptable, hash: slot2);
298	if (hslot->count < hslot2->count)
299	goto scan_primary_hash;
300
301	exist = udp_lib_lport_inuse2(net, num: snum, hslot2, sk);
302	if (!exist && (hash2_nulladdr != slot2)) {
303	hslot2 = udp_hashslot2(table: udptable, hash: hash2_nulladdr);
304	exist = udp_lib_lport_inuse2(net, num: snum, hslot2,
305	sk);
306	}
307	if (exist)
308	goto fail_unlock;
309	else
310	goto found;
311	}
312	scan_primary_hash:
313	if (udp_lib_lport_inuse(net, num: snum, hslot, NULL, sk, log: `0`))
314	goto fail_unlock;
315	}
316	found:
317	inet_sk(sk)->inet_num = snum;
318	udp_sk(sk)->udp_port_hash = snum;
319	udp_sk(sk)->udp_portaddr_hash ^= snum;
320	if (sk_unhashed(sk)) {
321	if (sk->sk_reuseport &&
322	udp_reuseport_add_sock(sk, hslot)) {
323	inet_sk(sk)->inet_num = `0`;
324	udp_sk(sk)->udp_port_hash = `0`;
325	udp_sk(sk)->udp_portaddr_hash ^= snum;
326	goto fail_unlock;
327	}
328
329	sock_set_flag(sk, flag: SOCK_RCU_FREE);
330
331	sk_add_node_rcu(sk, list: &hslot->head);
332	hslot->count++;
333	sock_prot_inuse_add(net: sock_net(sk), prot: sk->sk_prot, val: `1`);
334
335	hslot2 = udp_hashslot2(table: udptable, udp_sk(sk)->udp_portaddr_hash);
336	spin_lock(lock: &hslot2->lock);
337	if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
338	sk->sk_family == AF_INET6)
339	hlist_add_tail_rcu(n: &udp_sk(sk)->udp_portaddr_node,
340	h: &hslot2->head);
341	else
342	hlist_add_head_rcu(n: &udp_sk(sk)->udp_portaddr_node,
343	h: &hslot2->head);
344	hslot2->count++;
345	spin_unlock(lock: &hslot2->lock);
346	}
347
348	error = `0`;
349	fail_unlock:
350	spin_unlock_bh(lock: &hslot->lock);
351	fail:
352	return error;
353	}
354	EXPORT_IPV6_MOD(udp_lib_get_port);
355
356	int udp_v4_get_port(struct sock sk, unsigned* short snum)
357	{
358	unsigned int hash2_nulladdr =
359	ipv4_portaddr_hash(net: sock_net(sk), htonl(INADDR_ANY), port: snum);
360	unsigned int hash2_partial =
361	ipv4_portaddr_hash(net: sock_net(sk), inet_sk(sk)->inet_rcv_saddr, port: `0`);
362
363	/ precompute partial secondary hash /
364	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
365	return udp_lib_get_port(sk, snum, hash2_nulladdr);
366	}
367
368	static int compute_score(struct sock sk, const* struct net *net,
369	__be32 saddr, __be16 sport,
370	__be32 daddr, unsigned short hnum,
371	int dif, int sdif)
372	{
373	int score;
374	struct inet_sock *inet;
375	bool dev_match;
376
377	if (!net_eq(net1: sock_net(sk), net2: net) \|\|
378	udp_sk(sk)->udp_port_hash != hnum \|\|
379	ipv6_only_sock(sk))
380	return -`1`;
381
382	if (sk->sk_rcv_saddr != daddr)
383	return -`1`;
384
385	score = (sk->sk_family == PF_INET) ? `2` : `1`;
386
387	inet = inet_sk(sk);
388	if (inet->inet_daddr) {
389	if (inet->inet_daddr != saddr)
390	return -`1`;
391	score += `4`;
392	}
393
394	if (inet->inet_dport) {
395	if (inet->inet_dport != sport)
396	return -`1`;
397	score += `4`;
398	}
399
400	dev_match = udp_sk_bound_dev_eq(net, bound_dev_if: sk->sk_bound_dev_if,
401	dif, sdif);
402	if (!dev_match)
403	return -`1`;
404	if (sk->sk_bound_dev_if)
405	score += `4`;
406
407	if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
408	score++;
409	return score;
410	}
411
412	u32 udp_ehashfn(const struct net net, const* __be32 laddr, const __u16 lport,
413	const __be32 faddr, const __be16 fport)
414	{
415	net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret));
416
417	return __inet_ehashfn(laddr, lport, faddr, fport,
418	udp_ehash_secret + net_hash_mix(net));
419	}
420	EXPORT_IPV6_MOD(udp_ehashfn);
421
422	/**
423	* udp4_lib_lookup1() - Simplified lookup using primary hash (destination port)
424	* @net: Network namespace
425	* @saddr: Source address, network order
426	* @sport: Source port, network order
427	* @daddr: Destination address, network order
428	* @hnum: Destination port, host order
429	* @dif: Destination interface index
430	* @sdif: Destination bridge port index, if relevant
431	* @udptable: Set of UDP hash tables
432	*
433	* Simplified lookup to be used as fallback if no sockets are found due to a
434	* potential race between (receive) address change, and lookup happening before
435	* the rehash operation. This function ignores SO_REUSEPORT groups while scoring
436	* result sockets, because if we have one, we don't need the fallback at all.
437	*
438	* Called under rcu_read_lock().
439	*
440	* Return: socket with highest matching score if any, NULL if none
441	*/
442	static struct sock udp4_lib_lookup1(const* struct net *net,
443	__be32 saddr, __be16 sport,
444	__be32 daddr, unsigned int hnum,
445	int dif, int sdif,
446	const struct udp_table *udptable)
447	{
448	unsigned int slot = udp_hashfn(net, num: hnum, mask: udptable->mask);
449	struct udp_hslot *hslot = &udptable->hash[slot];
450	struct sock sk, result = NULL;
451	int score, badness = `0`;
452
453	sk_for_each_rcu(sk, &hslot->head) {
454	score = compute_score(sk, net,
455	saddr, sport, daddr, hnum, dif, sdif);
456	if (score > badness) {
457	result = sk;
458	badness = score;
459	}
460	}
461
462	return result;
463	}
464
465	/ called with rcu_read_lock() /
466	static struct sock udp4_lib_lookup2(const* struct net *net,
467	__be32 saddr, __be16 sport,
468	__be32 daddr, unsigned int hnum,
469	int dif, int sdif,
470	struct udp_hslot *hslot2,
471	struct sk_buff *skb)
472	{
473	struct sock sk, result;
474	int score, badness;
475	bool need_rescore;
476
477	result = NULL;
478	badness = `0`;
479	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
480	need_rescore = false;
481	rescore:
482	score = compute_score(sk: need_rescore ? result : sk, net, saddr,
483	sport, daddr, hnum, dif, sdif);
484	if (score > badness) {
485	badness = score;
486
487	if (need_rescore)
488	continue;
489
490	if (sk->sk_state == TCP_ESTABLISHED) {
491	result = sk;
492	continue;
493	}
494
495	result = inet_lookup_reuseport(net, sk, skb, doff: sizeof(struct udphdr),
496	saddr, sport, daddr, hnum, ehashfn: udp_ehashfn);
497	if (!result) {
498	result = sk;
499	continue;
500	}
501
502	/ Fall back to scoring if group has connections /
503	if (!reuseport_has_conns(sk))
504	return result;
505
506	/ Reuseport logic returned an error, keep original score. /
507	if (IS_ERR(ptr: result))
508	continue;
509
510	/ compute_score is too long of a function to be*
511	* inlined, and calling it again here yields
512	* measurable overhead for some
513	* workloads. Work around it by jumping
514	* backwards to rescore 'result'.
515	*/
516	need_rescore = true;
517	goto rescore;
518	}
519	}
520	return result;
521	}
522
523	#if IS_ENABLED(CONFIG_BASE_SMALL)
524	static struct sock udp4_lib_lookup4(const* struct net *net,
525	__be32 saddr, __be16 sport,
526	__be32 daddr, unsigned int hnum,
527	int dif, int sdif,
528	struct udp_table *udptable)
529	{
530	return NULL;
531	}
532
533	static void udp_rehash4(struct udp_table udptable, struct* sock *sk,
534	u16 newhash4)
535	{
536	}
537
538	static void udp_unhash4(struct udp_table udptable, struct* sock *sk)
539	{
540	}
541	#else /* !CONFIG_BASE_SMALL */
542	static struct sock udp4_lib_lookup4(const* struct net *net,
543	__be32 saddr, __be16 sport,
544	__be32 daddr, unsigned int hnum,
545	int dif, int sdif,
546	struct udp_table *udptable)
547	{
548	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
549	const struct hlist_nulls_node *node;
550	struct udp_hslot *hslot4;
551	unsigned int hash4, slot;
552	struct udp_sock *up;
553	struct sock *sk;
554
555	hash4 = udp_ehashfn(net, laddr: daddr, lport: hnum, faddr: saddr, fport: sport);
556	slot = hash4 & udptable->mask;
557	hslot4 = &udptable->hash4[slot];
558	INET_ADDR_COOKIE(acookie, saddr, daddr);
559
560	begin:
561	/ SLAB_TYPESAFE_BY_RCU not used, so we don't need to touch sk_refcnt /
562	udp_lrpa_for_each_entry_rcu(up, node, &hslot4->nulls_head) {
563	sk = (struct sock *)up;
564	if (inet_match(net, sk, cookie: acookie, ports, dif, sdif))
565	return sk;
566	}
567
568	/ if the nulls value we got at the end of this lookup is not the*
569	* expected one, we must restart lookup. We probably met an item that
570	* was moved to another chain due to rehash.
571	*/
572	if (get_nulls_value(ptr: node) != slot)
573	goto begin;
574
575	return NULL;
576	}
577
578	/ udp_rehash4() only checks hslot4, and hash4_cnt is not processed. /
579	static void udp_rehash4(struct udp_table udptable, struct* sock *sk,
580	u16 newhash4)
581	{
582	struct udp_hslot hslot4, nhslot4;
583
584	hslot4 = udp_hashslot4(table: udptable, udp_sk(sk)->udp_lrpa_hash);
585	nhslot4 = udp_hashslot4(table: udptable, hash: newhash4);
586	udp_sk(sk)->udp_lrpa_hash = newhash4;
587
588	if (hslot4 != nhslot4) {
589	spin_lock_bh(lock: &hslot4->lock);
590	hlist_nulls_del_init_rcu(n: &udp_sk(sk)->udp_lrpa_node);
591	hslot4->count--;
592	spin_unlock_bh(lock: &hslot4->lock);
593
594	spin_lock_bh(lock: &nhslot4->lock);
595	hlist_nulls_add_head_rcu(n: &udp_sk(sk)->udp_lrpa_node,
596	h: &nhslot4->nulls_head);
597	nhslot4->count++;
598	spin_unlock_bh(lock: &nhslot4->lock);
599	}
600	}
601
602	static void udp_unhash4(struct udp_table udptable, struct* sock *sk)
603	{
604	struct udp_hslot hslot2, hslot4;
605
606	if (udp_hashed4(sk)) {
607	hslot2 = udp_hashslot2(table: udptable, udp_sk(sk)->udp_portaddr_hash);
608	hslot4 = udp_hashslot4(table: udptable, udp_sk(sk)->udp_lrpa_hash);
609
610	spin_lock(lock: &hslot4->lock);
611	hlist_nulls_del_init_rcu(n: &udp_sk(sk)->udp_lrpa_node);
612	hslot4->count--;
613	spin_unlock(lock: &hslot4->lock);
614
615	spin_lock(lock: &hslot2->lock);
616	udp_hash4_dec(hslot2);
617	spin_unlock(lock: &hslot2->lock);
618	}
619	}
620
621	void udp_lib_hash4(struct sock *sk, u16 hash)
622	{
623	struct udp_hslot hslot, hslot2, *hslot4;
624	struct net *net = sock_net(sk);
625	struct udp_table *udptable;
626
627	/ Connected udp socket can re-connect to another remote address, which*
628	* will be handled by rehash. Thus no need to redo hash4 here.
629	*/
630	if (udp_hashed4(sk))
631	return;
632
633	udptable = net->ipv4.udp_table;
634	hslot = udp_hashslot(table: udptable, net, udp_sk(sk)->udp_port_hash);
635	hslot2 = udp_hashslot2(table: udptable, udp_sk(sk)->udp_portaddr_hash);
636	hslot4 = udp_hashslot4(table: udptable, hash);
637	udp_sk(sk)->udp_lrpa_hash = hash;
638
639	spin_lock_bh(lock: &hslot->lock);
640	if (rcu_access_pointer(sk->sk_reuseport_cb))
641	reuseport_detach_sock(sk);
642
643	spin_lock(lock: &hslot4->lock);
644	hlist_nulls_add_head_rcu(n: &udp_sk(sk)->udp_lrpa_node,
645	h: &hslot4->nulls_head);
646	hslot4->count++;
647	spin_unlock(lock: &hslot4->lock);
648
649	spin_lock(lock: &hslot2->lock);
650	udp_hash4_inc(hslot2);
651	spin_unlock(lock: &hslot2->lock);
652
653	spin_unlock_bh(lock: &hslot->lock);
654	}
655	EXPORT_IPV6_MOD(udp_lib_hash4);
656
657	/ call with sock lock /
658	void udp4_hash4(struct sock *sk)
659	{
660	struct net *net = sock_net(sk);
661	unsigned int hash;
662
663	if (sk_unhashed(sk) \|\| sk->sk_rcv_saddr == htonl(INADDR_ANY))
664	return;
665
666	hash = udp_ehashfn(net, laddr: sk->sk_rcv_saddr, lport: sk->sk_num,
667	faddr: sk->sk_daddr, fport: sk->sk_dport);
668
669	udp_lib_hash4(sk, hash);
670	}
671	EXPORT_IPV6_MOD(udp4_hash4);
672	#endif /* CONFIG_BASE_SMALL */
673
674	/ UDP is nearly always wildcards out the wazoo, it makes no sense to try*
675	* harder than this. -DaveM
676	*/
677	struct sock __udp4_lib_lookup(const* struct net *net, __be32 saddr,
678	__be16 sport, __be32 daddr, __be16 dport, int dif,
679	int sdif, struct udp_table udptable, struct* sk_buff *skb)
680	{
681	unsigned short hnum = ntohs(dport);
682	struct udp_hslot *hslot2;
683	struct sock result, sk;
684	unsigned int hash2;
685
686	hash2 = ipv4_portaddr_hash(net, saddr: daddr, port: hnum);
687	hslot2 = udp_hashslot2(table: udptable, hash: hash2);
688
689	if (udp_has_hash4(hslot2)) {
690	result = udp4_lib_lookup4(net, saddr, sport, daddr, hnum,
691	dif, sdif, udptable);
692	if (result) / udp4_lib_lookup4 return sk or NULL /
693	return result;
694	}
695
696	/ Lookup connected or non-wildcard socket /
697	result = udp4_lib_lookup2(net, saddr, sport,
698	daddr, hnum, dif, sdif,
699	hslot2, skb);
700	if (!IS_ERR_OR_NULL(ptr: result) && result->sk_state == TCP_ESTABLISHED)
701	goto done;
702
703	/ Lookup redirect from BPF /
704	if (static_branch_unlikely(&bpf_sk_lookup_enabled) &&
705	udptable == net->ipv4.udp_table) {
706	sk = inet_lookup_run_sk_lookup(net, IPPROTO_UDP, skb, doff: sizeof(struct udphdr),
707	saddr, sport, daddr, hnum, dif,
708	ehashfn: udp_ehashfn);
709	if (sk) {
710	result = sk;
711	goto done;
712	}
713	}
714
715	/ Got non-wildcard socket or error on first lookup /
716	if (result)
717	goto done;
718
719	/ Lookup wildcard sockets /
720	hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), port: hnum);
721	hslot2 = udp_hashslot2(table: udptable, hash: hash2);
722
723	result = udp4_lib_lookup2(net, saddr, sport,
724	htonl(INADDR_ANY), hnum, dif, sdif,
725	hslot2, skb);
726	if (!IS_ERR_OR_NULL(ptr: result))
727	goto done;
728
729	/ Primary hash (destination port) lookup as fallback for this race:*
730	* 1. __ip4_datagram_connect() sets sk_rcv_saddr
731	* 2. lookup (this function): new sk_rcv_saddr, hashes not updated yet
732	* 3. rehash operation updating _secondary and four-tuple_ hashes
733	* The primary hash doesn't need an update after 1., so, thanks to this
734	* further step, 1. and 3. don't need to be atomic against the lookup.
735	*/
736	result = udp4_lib_lookup1(net, saddr, sport, daddr, hnum, dif, sdif,
737	udptable);
738
739	done:
740	if (IS_ERR(ptr: result))
741	return NULL;
742	return result;
743	}
744	EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
745
746	static inline struct sock __udp4_lib_lookup_skb(struct* sk_buff *skb,
747	__be16 sport, __be16 dport,
748	struct udp_table *udptable)
749	{
750	const struct iphdr *iph = ip_hdr(skb);
751
752	return __udp4_lib_lookup(dev_net(dev: skb->dev), iph->saddr, sport,
753	iph->daddr, dport, inet_iif(skb),
754	inet_sdif(skb), udptable, skb);
755	}
756
757	struct sock udp4_lib_lookup_skb(const* struct sk_buff *skb,
758	__be16 sport, __be16 dport)
759	{
760	const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation];
761	const struct iphdr iph = (struct* iphdr *)(skb->data + offset);
762	struct net *net = dev_net(dev: skb->dev);
763	int iif, sdif;
764
765	inet_get_iif_sdif(skb, iif: &iif, sdif: &sdif);
766
767	return __udp4_lib_lookup(net, iph->saddr, sport,
768	iph->daddr, dport, iif,
769	sdif, net->ipv4.udp_table, NULL);
770	}
771
772	/ Must be called under rcu_read_lock().*
773	* Does increment socket refcount.
774	*/
775	#if IS_ENABLED(CONFIG_NF_TPROXY_IPV4) \|\| IS_ENABLED(CONFIG_NF_SOCKET_IPV4)
776	struct sock udp4_lib_lookup(const* struct net *net, __be32 saddr, __be16 sport,
777	__be32 daddr, __be16 dport, int dif)
778	{
779	struct sock *sk;
780
781	sk = __udp4_lib_lookup(net, saddr, sport, daddr, dport,
782	dif, `0`, net->ipv4.udp_table, NULL);
783	if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
784	sk = NULL;
785	return sk;
786	}
787	EXPORT_SYMBOL_GPL(udp4_lib_lookup);
788	#endif
789
790	static inline bool __udp_is_mcast_sock(struct net net, const* struct sock *sk,
791	__be16 loc_port, __be32 loc_addr,
792	__be16 rmt_port, __be32 rmt_addr,
793	int dif, int sdif, unsigned short hnum)
794	{
795	const struct inet_sock *inet = inet_sk(sk);
796
797	if (!net_eq(net1: sock_net(sk), net2: net) \|\|
798	udp_sk(sk)->udp_port_hash != hnum \|\|
799	(inet->inet_daddr && inet->inet_daddr != rmt_addr) \|\|
800	(inet->inet_dport != rmt_port && inet->inet_dport) \|\|
801	(inet->inet_rcv_saddr && inet->inet_rcv_saddr != loc_addr) \|\|
802	ipv6_only_sock(sk) \|\|
803	!udp_sk_bound_dev_eq(net, bound_dev_if: sk->sk_bound_dev_if, dif, sdif))
804	return false;
805	if (!ip_mc_sf_allow(sk, local: loc_addr, rmt: rmt_addr, dif, sdif))
806	return false;
807	return true;
808	}
809
810	DEFINE_STATIC_KEY_FALSE(udp_encap_needed_key);
811	EXPORT_IPV6_MOD(udp_encap_needed_key);
812
813	#if IS_ENABLED(CONFIG_IPV6)
814	DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
815	EXPORT_IPV6_MOD(udpv6_encap_needed_key);
816	#endif
817
818	void udp_encap_enable(void)
819	{
820	static_branch_inc(&udp_encap_needed_key);
821	}
822	EXPORT_SYMBOL(udp_encap_enable);
823
824	void udp_encap_disable(void)
825	{
826	static_branch_dec(&udp_encap_needed_key);
827	}
828	EXPORT_SYMBOL(udp_encap_disable);
829
830	/ Handler for tunnels with arbitrary destination ports: no socket lookup, go*
831	* through error handlers in encapsulations looking for a match.
832	*/
833	static int __udp4_lib_err_encap_no_sk(struct sk_buff *skb, u32 info)
834	{
835	int i;
836
837	for (i = `0`; i < MAX_IPTUN_ENCAP_OPS; i++) {
838	int (handler)(struct* sk_buff *skb, u32 info);
839	const struct ip_tunnel_encap_ops *encap;
840
841	encap = rcu_dereference(iptun_encaps[i]);
842	if (!encap)
843	continue;
844	handler = encap->err_handler;
845	if (handler && !handler(skb, info))
846	return `0`;
847	}
848
849	return -ENOENT;
850	}
851
852	/ Try to match ICMP errors to UDP tunnels by looking up a socket without*
853	* reversing source and destination port: this will match tunnels that force the
854	* same destination port on both endpoints (e.g. VXLAN, GENEVE). Note that
855	* lwtunnels might actually break this assumption by being configured with
856	* different destination ports on endpoints, in this case we won't be able to
857	* trace ICMP messages back to them.
858	*
859	* If this doesn't match any socket, probe tunnels with arbitrary destination
860	* ports (e.g. FoU, GUE): there, the receiving socket is useless, as the port
861	* we've sent packets to won't necessarily match the local destination port.
862	*
863	* Then ask the tunnel implementation to match the error against a valid
864	* association.
865	*
866	* Return an error if we can't find a match, the socket if we need further
867	* processing, zero otherwise.
868	*/
869	static struct sock __udp4_lib_err_encap(struct* net *net,
870	const struct iphdr *iph,
871	struct udphdr *uh,
872	struct udp_table *udptable,
873	struct sock *sk,
874	struct sk_buff *skb, u32 info)
875	{
876	int (lookup)(struct* sock sk, struct* sk_buff *skb);
877	int network_offset, transport_offset;
878	struct udp_sock *up;
879
880	network_offset = skb_network_offset(skb);
881	transport_offset = skb_transport_offset(skb);
882
883	/ Network header needs to point to the outer IPv4 header inside ICMP /
884	skb_reset_network_header(skb);
885
886	/ Transport header needs to point to the UDP header /
887	skb_set_transport_header(skb, offset: iph->ihl << `2`);
888
889	if (sk) {
890	up = udp_sk(sk);
891
892	lookup = READ_ONCE(up->encap_err_lookup);
893	if (lookup && lookup(sk, skb))
894	sk = NULL;
895
896	goto out;
897	}
898
899	sk = __udp4_lib_lookup(net, iph->daddr, uh->source,
900	iph->saddr, uh->dest, skb->dev->ifindex, `0`,
901	udptable, NULL);
902	if (sk) {
903	up = udp_sk(sk);
904
905	lookup = READ_ONCE(up->encap_err_lookup);
906	if (!lookup \|\| lookup(sk, skb))
907	sk = NULL;
908	}
909
910	out:
911	if (!sk)
912	sk = ERR_PTR(error: __udp4_lib_err_encap_no_sk(skb, info));
913
914	skb_set_transport_header(skb, offset: transport_offset);
915	skb_set_network_header(skb, offset: network_offset);
916
917	return sk;
918	}
919
920	/*
921	* This routine is called by the ICMP module when it gets some
922	* sort of error condition. If err < 0 then the socket should
923	* be closed and the error returned to the user. If err > 0
924	* it's just the icmp type << 8 \| icmp code.
925	* Header points to the ip header of the error packet. We move
926	* on past this. Then (as it used to claim before adjustment)
927	* header points to the first 8 bytes of the udp header. We need
928	* to find the appropriate port.
929	*/
930
931	int __udp4_lib_err(struct sk_buff skb, u32 info, struct* udp_table *udptable)
932	{
933	struct inet_sock *inet;
934	const struct iphdr iph = (const* struct iphdr *)skb->data;
935	struct udphdr uh = (struct* udphdr *)(skb->data+(iph->ihl<<`2`));
936	const int type = icmp_hdr(skb)->type;
937	const int code = icmp_hdr(skb)->code;
938	bool tunnel = false;
939	struct sock *sk;
940	int harderr;
941	int err;
942	struct net *net = dev_net(dev: skb->dev);
943
944	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
945	iph->saddr, uh->source, skb->dev->ifindex,
946	inet_sdif(skb), udptable, NULL);
947
948	if (!sk \|\| READ_ONCE(udp_sk(sk)->encap_type)) {
949	/ No socket for error: try tunnels before discarding /
950	if (static_branch_unlikely(&udp_encap_needed_key)) {
951	sk = __udp4_lib_err_encap(net, iph, uh, udptable, sk, skb,
952	info);
953	if (!sk)
954	return `0`;
955	} else
956	sk = ERR_PTR(error: -ENOENT);
957
958	if (IS_ERR(ptr: sk)) {
959	__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
960	return PTR_ERR(ptr: sk);
961	}
962
963	tunnel = true;
964	}
965
966	err = `0`;
967	harderr = `0`;
968	inet = inet_sk(sk);
969
970	switch (type) {
971	default:
972	case ICMP_TIME_EXCEEDED:
973	err = EHOSTUNREACH;
974	break;
975	case ICMP_SOURCE_QUENCH:
976	goto out;
977	case ICMP_PARAMETERPROB:
978	err = EPROTO;
979	harderr = `1`;
980	break;
981	case ICMP_DEST_UNREACH:
982	if (code == ICMP_FRAG_NEEDED) { / Path MTU discovery /
983	ipv4_sk_update_pmtu(skb, sk, mtu: info);
984	if (READ_ONCE(inet->pmtudisc) != IP_PMTUDISC_DONT) {
985	err = EMSGSIZE;
986	harderr = `1`;
987	break;
988	}
989	goto out;
990	}
991	err = EHOSTUNREACH;
992	if (code <= NR_ICMP_UNREACH) {
993	harderr = icmp_err_convert[code].fatal;
994	err = icmp_err_convert[code].errno;
995	}
996	break;
997	case ICMP_REDIRECT:
998	ipv4_sk_redirect(skb, sk);
999	goto out;
1000	}
1001
1002	/*
1003	* RFC1122: OK. Passes ICMP errors back to application, as per
1004	* 4.1.3.3.
1005	*/
1006	if (tunnel) {
1007	/ ...not for tunnels though: we don't have a sending socket /
1008	if (udp_sk(sk)->encap_err_rcv)
1009	udp_sk(sk)->encap_err_rcv(sk, skb, err, uh->dest, info,
1010	(u8 *)(uh+`1`));
1011	goto out;
1012	}
1013	if (!inet_test_bit(RECVERR, sk)) {
1014	if (!harderr \|\| sk->sk_state != TCP_ESTABLISHED)
1015	goto out;
1016	} else
1017	ip_icmp_error(sk, skb, err, port: uh->dest, info, payload: (u8 *)(uh+`1`));
1018
1019	sk->sk_err = err;
1020	sk_error_report(sk);
1021	out:
1022	return `0`;
1023	}
1024
1025	int udp_err(struct sk_buff *skb, u32 info)
1026	{
1027	return __udp4_lib_err(skb, info, udptable: dev_net(dev: skb->dev)->ipv4.udp_table);
1028	}
1029
1030	/*
1031	* Throw away all pending data and cancel the corking. Socket is locked.
1032	*/
1033	void udp_flush_pending_frames(struct sock *sk)
1034	{
1035	struct udp_sock *up = udp_sk(sk);
1036
1037	if (up->pending) {
1038	up->len = `0`;
1039	WRITE_ONCE(up->pending, `0`);
1040	ip_flush_pending_frames(sk);
1041	}
1042	}
1043	EXPORT_IPV6_MOD(udp_flush_pending_frames);
1044
1045	/**
1046	* udp4_hwcsum - handle outgoing HW checksumming
1047	* @skb: sk_buff containing the filled-in UDP header
1048	* (checksum field must be zeroed out)
1049	* @src: source IP address
1050	* @dst: destination IP address
1051	*/
1052	void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
1053	{
1054	struct udphdr *uh = udp_hdr(skb);
1055	int offset = skb_transport_offset(skb);
1056	int len = skb->len - offset;
1057	int hlen = len;
1058	__wsum csum = `0`;
1059
1060	if (!skb_has_frag_list(skb)) {
1061	/*
1062	* Only one fragment on the socket.
1063	*/
1064	skb->csum_start = skb_transport_header(skb) - skb->head;
1065	skb->csum_offset = offsetof(struct udphdr, check);
1066	uh->check = ~csum_tcpudp_magic(saddr: src, daddr: dst, len,
1067	IPPROTO_UDP, sum: `0`);
1068	} else {
1069	struct sk_buff *frags;
1070
1071	/*
1072	* HW-checksum won't work as there are two or more
1073	* fragments on the socket so that all csums of sk_buffs
1074	* should be together
1075	*/
1076	skb_walk_frags(skb, frags) {
1077	csum = csum_add(csum, addend: frags->csum);
1078	hlen -= frags->len;
1079	}
1080
1081	csum = skb_checksum(skb, offset, len: hlen, csum);
1082	skb->ip_summed = CHECKSUM_NONE;
1083
1084	uh->check = csum_tcpudp_magic(saddr: src, daddr: dst, len, IPPROTO_UDP, sum: csum);
1085	if (uh->check == `0`)
1086	uh->check = CSUM_MANGLED_0;
1087	}
1088	}
1089	EXPORT_SYMBOL_GPL(udp4_hwcsum);
1090
1091	/ Function to set UDP checksum for an IPv4 UDP packet. This is intended*
1092	* for the simple case like when setting the checksum for a UDP tunnel.
1093	*/
1094	void udp_set_csum(bool nocheck, struct sk_buff *skb,
1095	__be32 saddr, __be32 daddr, int len)
1096	{
1097	struct udphdr *uh = udp_hdr(skb);
1098
1099	if (nocheck) {
1100	uh->check = `0`;
1101	} else if (skb_is_gso(skb)) {
1102	uh->check = ~udp_v4_check(len, saddr, daddr, base: `0`);
1103	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
1104	uh->check = `0`;
1105	uh->check = udp_v4_check(len, saddr, daddr, base: lco_csum(skb));
1106	if (uh->check == `0`)
1107	uh->check = CSUM_MANGLED_0;
1108	} else {
1109	skb->ip_summed = CHECKSUM_PARTIAL;
1110	skb->csum_start = skb_transport_header(skb) - skb->head;
1111	skb->csum_offset = offsetof(struct udphdr, check);
1112	uh->check = ~udp_v4_check(len, saddr, daddr, base: `0`);
1113	}
1114	}
1115	EXPORT_SYMBOL(udp_set_csum);
1116
1117	static int udp_send_skb(struct sk_buff skb, struct* flowi4 *fl4,
1118	struct inet_cork *cork)
1119	{
1120	struct sock *sk = skb->sk;
1121	struct inet_sock *inet = inet_sk(sk);
1122	struct udphdr *uh;
1123	int err;
1124	int is_udplite = IS_UDPLITE(sk);
1125	int offset = skb_transport_offset(skb);
1126	int len = skb->len - offset;
1127	int datalen = len - sizeof(*uh);
1128	__wsum csum = `0`;
1129
1130	/*
1131	* Create a UDP header
1132	*/
1133	uh = udp_hdr(skb);
1134	uh->source = inet->inet_sport;
1135	uh->dest = fl4->fl4_dport;
1136	uh->len = htons(len);
1137	uh->check = `0`;
1138
1139	if (cork->gso_size) {
1140	const int hlen = skb_network_header_len(skb) +
1141	sizeof(struct udphdr);
1142
1143	if (hlen + min(datalen, cork->gso_size) > cork->fragsize) {
1144	kfree_skb(skb);
1145	return -EMSGSIZE;
1146	}
1147	if (datalen > cork->gso_size * UDP_MAX_SEGMENTS) {
1148	kfree_skb(skb);
1149	return -EINVAL;
1150	}
1151	if (sk->sk_no_check_tx) {
1152	kfree_skb(skb);
1153	return -EINVAL;
1154	}
1155	if (is_udplite \|\| dst_xfrm(dst: skb_dst(skb))) {
1156	kfree_skb(skb);
1157	return -EIO;
1158	}
1159
1160	if (datalen > cork->gso_size) {
1161	skb_shinfo(skb)->gso_size = cork->gso_size;
1162	skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
1163	skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(datalen,
1164	cork->gso_size);
1165
1166	/ Don't checksum the payload, skb will get segmented /
1167	goto csum_partial;
1168	}
1169	}
1170
1171	if (is_udplite) / UDP-Lite /
1172	csum = udplite_csum(skb);
1173
1174	else if (sk->sk_no_check_tx) { / UDP csum off /
1175
1176	skb->ip_summed = CHECKSUM_NONE;
1177	goto send;
1178
1179	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { / UDP hardware csum /
1180	csum_partial:
1181
1182	udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
1183	goto send;
1184
1185	} else
1186	csum = udp_csum(skb);
1187
1188	/ add protocol-dependent pseudo-header /
1189	uh->check = csum_tcpudp_magic(saddr: fl4->saddr, daddr: fl4->daddr, len,
1190	proto: sk->sk_protocol, sum: csum);
1191	if (uh->check == `0`)
1192	uh->check = CSUM_MANGLED_0;
1193
1194	send:
1195	err = ip_send_skb(net: sock_net(sk), skb);
1196	if (err) {
1197	if (err == -ENOBUFS &&
1198	!inet_test_bit(RECVERR, sk)) {
1199	UDP_INC_STATS(sock_net(sk),
1200	UDP_MIB_SNDBUFERRORS, is_udplite);
1201	err = `0`;
1202	}
1203	} else
1204	UDP_INC_STATS(sock_net(sk),
1205	UDP_MIB_OUTDATAGRAMS, is_udplite);
1206	return err;
1207	}
1208
1209	/*
1210	* Push out all pending data as one UDP datagram. Socket is locked.
1211	*/
1212	int udp_push_pending_frames(struct sock *sk)
1213	{
1214	struct udp_sock *up = udp_sk(sk);
1215	struct inet_sock *inet = inet_sk(sk);
1216	struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
1217	struct sk_buff *skb;
1218	int err = `0`;
1219
1220	skb = ip_finish_skb(sk, fl4);
1221	if (!skb)
1222	goto out;
1223
1224	err = udp_send_skb(skb, fl4, cork: &inet->cork.base);
1225
1226	out:
1227	up->len = `0`;
1228	WRITE_ONCE(up->pending, `0`);
1229	return err;
1230	}
1231	EXPORT_IPV6_MOD(udp_push_pending_frames);
1232
1233	static int __udp_cmsg_send(struct cmsghdr cmsg, u16 gso_size)
1234	{
1235	switch (cmsg->cmsg_type) {
1236	case UDP_SEGMENT:
1237	if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u16)))
1238	return -EINVAL;
1239	gso_size = (__u16 *)CMSG_DATA(cmsg);
1240	return `0`;
1241	default:
1242	return -EINVAL;
1243	}
1244	}
1245
1246	int udp_cmsg_send(struct sock sk, struct* msghdr msg, u16 gso_size)
1247	{
1248	struct cmsghdr *cmsg;
1249	bool need_ip = false;
1250	int err;
1251
1252	for_each_cmsghdr(cmsg, msg) {
1253	if (!CMSG_OK(msg, cmsg))
1254	return -EINVAL;
1255
1256	if (cmsg->cmsg_level != SOL_UDP) {
1257	need_ip = true;
1258	continue;
1259	}
1260
1261	err = __udp_cmsg_send(cmsg, gso_size);
1262	if (err)
1263	return err;
1264	}
1265
1266	return need_ip;
1267	}
1268	EXPORT_IPV6_MOD_GPL(udp_cmsg_send);
1269
1270	int udp_sendmsg(struct sock sk, struct* msghdr *msg, size_t len)
1271	{
1272	struct inet_sock *inet = inet_sk(sk);
1273	struct udp_sock *up = udp_sk(sk);
1274	DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
1275	struct flowi4 fl4_stack;
1276	struct flowi4 *fl4;
1277	int ulen = len;
1278	struct ipcm_cookie ipc;
1279	struct rtable *rt = NULL;
1280	int free = `0`;
1281	int connected = `0`;
1282	__be32 daddr, faddr, saddr;
1283	u8 scope;
1284	__be16 dport;
1285	int err, is_udplite = IS_UDPLITE(sk);
1286	int corkreq = udp_test_bit(CORK, sk) \|\| msg->msg_flags & MSG_MORE;
1287	int (getfrag)(void* , char* , int, int, int, struct* sk_buff *);
1288	struct sk_buff *skb;
1289	struct ip_options_data opt_copy;
1290	int uc_index;
1291
1292	if (len > `0xFFFF`)
1293	return -EMSGSIZE;
1294
1295	/*
1296	* Check the flags.
1297	*/
1298
1299	if (msg->msg_flags & MSG_OOB) / Mirror BSD error message compatibility /
1300	return -EOPNOTSUPP;
1301
1302	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
1303
1304	fl4 = &inet->cork.fl.u.ip4;
1305	if (READ_ONCE(up->pending)) {
1306	/*
1307	* There are pending frames.
1308	* The socket lock must be held while it's corked.
1309	*/
1310	lock_sock(sk);
1311	if (likely(up->pending)) {
1312	if (unlikely(up->pending != AF_INET)) {
1313	release_sock(sk);
1314	return -EINVAL;
1315	}
1316	goto do_append_data;
1317	}
1318	release_sock(sk);
1319	}
1320	ulen += sizeof(struct udphdr);
1321
1322	/*
1323	* Get and verify the address.
1324	*/
1325	if (usin) {
1326	if (msg->msg_namelen < sizeof(*usin))
1327	return -EINVAL;
1328	if (usin->sin_family != AF_INET) {
1329	if (usin->sin_family != AF_UNSPEC)
1330	return -EAFNOSUPPORT;
1331	}
1332
1333	daddr = usin->sin_addr.s_addr;
1334	dport = usin->sin_port;
1335	if (dport == `0`)
1336	return -EINVAL;
1337	} else {
1338	if (sk->sk_state != TCP_ESTABLISHED)
1339	return -EDESTADDRREQ;
1340	daddr = inet->inet_daddr;
1341	dport = inet->inet_dport;
1342	/ Open fast path for connected socket.*
1343	Route will not be used, if at least one option is set.
1344	*/
1345	connected = `1`;
1346	}
1347
1348	ipcm_init_sk(ipcm: &ipc, inet);
1349	ipc.gso_size = READ_ONCE(up->gso_size);
1350
1351	if (msg->msg_controllen) {
1352	err = udp_cmsg_send(sk, msg, gso_size: &ipc.gso_size);
1353	if (err > `0`) {
1354	err = ip_cmsg_send(sk, msg, ipc: &ipc,
1355	allow_ipv6: sk->sk_family == AF_INET6);
1356	connected = `0`;
1357	}
1358	if (unlikely(err < `0`)) {
1359	kfree(objp: ipc.opt);
1360	return err;
1361	}
1362	if (ipc.opt)
1363	free = `1`;
1364	}
1365	if (!ipc.opt) {
1366	struct ip_options_rcu *inet_opt;
1367
1368	rcu_read_lock();
1369	inet_opt = rcu_dereference(inet->inet_opt);
1370	if (inet_opt) {
1371	memcpy(to: &opt_copy, from: inet_opt,
1372	len: sizeof(*inet_opt) + inet_opt->opt.optlen);
1373	ipc.opt = &opt_copy.opt;
1374	}
1375	rcu_read_unlock();
1376	}
1377
1378	if (cgroup_bpf_enabled(CGROUP_UDP4_SENDMSG) && !connected) {
1379	err = BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk,
1380	(struct sockaddr *)usin,
1381	&msg->msg_namelen,
1382	&ipc.addr);
1383	if (err)
1384	goto out_free;
1385	if (usin) {
1386	if (usin->sin_port == `0`) {
1387	/ BPF program set invalid port. Reject it. /
1388	err = -EINVAL;
1389	goto out_free;
1390	}
1391	daddr = usin->sin_addr.s_addr;
1392	dport = usin->sin_port;
1393	}
1394	}
1395
1396	saddr = ipc.addr;
1397	ipc.addr = faddr = daddr;
1398
1399	if (ipc.opt && ipc.opt->opt.srr) {
1400	if (!daddr) {
1401	err = -EINVAL;
1402	goto out_free;
1403	}
1404	faddr = ipc.opt->opt.faddr;
1405	connected = `0`;
1406	}
1407	scope = ip_sendmsg_scope(inet, ipc: &ipc, msg);
1408	if (scope == RT_SCOPE_LINK)
1409	connected = `0`;
1410
1411	uc_index = READ_ONCE(inet->uc_index);
1412	if (ipv4_is_multicast(addr: daddr)) {
1413	if (!ipc.oif \|\| netif_index_is_l3_master(net: sock_net(sk), ifindex: ipc.oif))
1414	ipc.oif = READ_ONCE(inet->mc_index);
1415	if (!saddr)
1416	saddr = READ_ONCE(inet->mc_addr);
1417	connected = `0`;
1418	} else if (!ipc.oif) {
1419	ipc.oif = uc_index;
1420	} else if (ipv4_is_lbcast(addr: daddr) && uc_index) {
1421	/ oif is set, packet is to local broadcast and*
1422	* uc_index is set. oif is most likely set
1423	* by sk_bound_dev_if. If uc_index != oif check if the
1424	* oif is an L3 master and uc_index is an L3 slave.
1425	* If so, we want to allow the send using the uc_index.
1426	*/
1427	if (ipc.oif != uc_index &&
1428	ipc.oif == l3mdev_master_ifindex_by_index(net: sock_net(sk),
1429	ifindex: uc_index)) {
1430	ipc.oif = uc_index;
1431	}
1432	}
1433
1434	if (connected)
1435	rt = dst_rtable(sk_dst_check(sk, `0`));
1436
1437	if (!rt) {
1438	struct net *net = sock_net(sk);
1439	__u8 flow_flags = inet_sk_flowi_flags(sk);
1440
1441	fl4 = &fl4_stack;
1442
1443	flowi4_init_output(fl4, oif: ipc.oif, mark: ipc.sockc.mark,
1444	tos: ipc.tos & INET_DSCP_MASK, scope,
1445	proto: sk->sk_protocol, flags: flow_flags, daddr: faddr, saddr,
1446	dport, sport: inet->inet_sport,
1447	uid: sk_uid(sk));
1448
1449	security_sk_classify_flow(sk, flic: flowi4_to_flowi_common(fl4));
1450	rt = ip_route_output_flow(net, flp: fl4, sk);
1451	if (IS_ERR(ptr: rt)) {
1452	err = PTR_ERR(ptr: rt);
1453	rt = NULL;
1454	if (err == -ENETUNREACH)
1455	IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
1456	goto out;
1457	}
1458
1459	err = -EACCES;
1460	if ((rt->rt_flags & RTCF_BROADCAST) &&
1461	!sock_flag(sk, flag: SOCK_BROADCAST))
1462	goto out;
1463	if (connected)
1464	sk_dst_set(sk, dst: dst_clone(dst: &rt->dst));
1465	}
1466
1467	if (msg->msg_flags&MSG_CONFIRM)
1468	goto do_confirm;
1469	back_from_confirm:
1470
1471	saddr = fl4->saddr;
1472	if (!ipc.addr)
1473	daddr = ipc.addr = fl4->daddr;
1474
1475	/ Lockless fast path for the non-corking case. /
1476	if (!corkreq) {
1477	struct inet_cork cork;
1478
1479	skb = ip_make_skb(sk, fl4, getfrag, from: msg, length: ulen,
1480	transhdrlen: sizeof(struct udphdr), ipc: &ipc, rtp: &rt,
1481	cork: &cork, flags: msg->msg_flags);
1482	err = PTR_ERR(ptr: skb);
1483	if (!IS_ERR_OR_NULL(ptr: skb))
1484	err = udp_send_skb(skb, fl4, cork: &cork);
1485	goto out;
1486	}
1487
1488	lock_sock(sk);
1489	if (unlikely(up->pending)) {
1490	/ The socket is already corked while preparing it. /
1491	/ ... which is an evident application bug. --ANK /
1492	release_sock(sk);
1493
1494	net_dbg_ratelimited("socket already corked\n");
1495	err = -EINVAL;
1496	goto out;
1497	}
1498	/*
1499	* Now cork the socket to pend data.
1500	*/
1501	fl4 = &inet->cork.fl.u.ip4;
1502	fl4->daddr = daddr;
1503	fl4->saddr = saddr;
1504	fl4->fl4_dport = dport;
1505	fl4->fl4_sport = inet->inet_sport;
1506	WRITE_ONCE(up->pending, AF_INET);
1507
1508	do_append_data:
1509	up->len += ulen;
1510	err = ip_append_data(sk, fl4, getfrag, from: msg, len: ulen,
1511	protolen: sizeof(struct udphdr), ipc: &ipc, rt: &rt,
1512	flags: corkreq ? msg->msg_flags\|MSG_MORE : msg->msg_flags);
1513	if (err)
1514	udp_flush_pending_frames(sk);
1515	else if (!corkreq)
1516	err = udp_push_pending_frames(sk);
1517	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1518	WRITE_ONCE(up->pending, `0`);
1519	release_sock(sk);
1520
1521	out:
1522	ip_rt_put(rt);
1523	out_free:
1524	if (free)
1525	kfree(objp: ipc.opt);
1526	if (!err)
1527	return len;
1528	/*
1529	* ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space. Reporting
1530	* ENOBUFS might not be good (it's not tunable per se), but otherwise
1531	* we don't have a good statistic (IpOutDiscards but it can be too many
1532	* things). We could add another new stat but at least for now that
1533	* seems like overkill.
1534	*/
1535	if (err == -ENOBUFS \|\| test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1536	UDP_INC_STATS(sock_net(sk),
1537	UDP_MIB_SNDBUFERRORS, is_udplite);
1538	}
1539	return err;
1540
1541	do_confirm:
1542	if (msg->msg_flags & MSG_PROBE)
1543	dst_confirm_neigh(dst: &rt->dst, daddr: &fl4->daddr);
1544	if (!(msg->msg_flags&MSG_PROBE) \|\| len)
1545	goto back_from_confirm;
1546	err = `0`;
1547	goto out;
1548	}
1549	EXPORT_SYMBOL(udp_sendmsg);
1550
1551	void udp_splice_eof(struct socket *sock)
1552	{
1553	struct sock *sk = sock->sk;
1554	struct udp_sock *up = udp_sk(sk);
1555
1556	if (!READ_ONCE(up->pending) \|\| udp_test_bit(CORK, sk))
1557	return;
1558
1559	lock_sock(sk);
1560	if (up->pending && !udp_test_bit(CORK, sk))
1561	udp_push_pending_frames(sk);
1562	release_sock(sk);
1563	}
1564	EXPORT_IPV6_MOD_GPL(udp_splice_eof);
1565
1566	#define UDP_SKB_IS_STATELESS 0x80000000
1567
1568	/ all head states (dst, sk, nf conntrack) except skb extensions are*
1569	* cleared by udp_rcv().
1570	*
1571	* We need to preserve secpath, if present, to eventually process
1572	* IP_CMSG_PASSSEC at recvmsg() time.
1573	*
1574	* Other extensions can be cleared.
1575	*/
1576	static bool udp_try_make_stateless(struct sk_buff *skb)
1577	{
1578	if (!skb_has_extensions(skb))
1579	return true;
1580
1581	if (!secpath_exists(skb)) {
1582	skb_ext_reset(skb);
1583	return true;
1584	}
1585
1586	return false;
1587	}
1588
1589	static void udp_set_dev_scratch(struct sk_buff *skb)
1590	{
1591	struct udp_dev_scratch *scratch = udp_skb_scratch(skb);
1592
1593	BUILD_BUG_ON(sizeof(struct udp_dev_scratch) > sizeof(long));
1594	scratch->_tsize_state = skb->truesize;
1595	#if BITS_PER_LONG == 64
1596	scratch->len = skb->len;
1597	scratch->csum_unnecessary = !!skb_csum_unnecessary(skb);
1598	scratch->is_linear = !skb_is_nonlinear(skb);
1599	#endif
1600	if (udp_try_make_stateless(skb))
1601	scratch->_tsize_state \|= UDP_SKB_IS_STATELESS;
1602	}
1603
1604	static void udp_skb_csum_unnecessary_set(struct sk_buff *skb)
1605	{
1606	/ We come here after udp_lib_checksum_complete() returned 0.*
1607	* This means that __skb_checksum_complete() might have
1608	* set skb->csum_valid to 1.
1609	* On 64bit platforms, we can set csum_unnecessary
1610	* to true, but only if the skb is not shared.
1611	*/
1612	#if BITS_PER_LONG == 64
1613	if (!skb_shared(skb))
1614	udp_skb_scratch(skb)->csum_unnecessary = true;
1615	#endif
1616	}
1617
1618	static int udp_skb_truesize(struct sk_buff *skb)
1619	{
1620	return udp_skb_scratch(skb)->_tsize_state & ~UDP_SKB_IS_STATELESS;
1621	}
1622
1623	static bool udp_skb_has_head_state(struct sk_buff *skb)
1624	{
1625	return !(udp_skb_scratch(skb)->_tsize_state & UDP_SKB_IS_STATELESS);
1626	}
1627
1628	/ fully reclaim rmem/fwd memory allocated for skb /
1629	static void udp_rmem_release(struct sock sk, unsigned* int size,
1630	int partial, bool rx_queue_lock_held)
1631	{
1632	struct udp_sock *up = udp_sk(sk);
1633	struct sk_buff_head *sk_queue;
1634	unsigned int amt;
1635
1636	if (likely(partial)) {
1637	up->forward_deficit += size;
1638	size = up->forward_deficit;
1639	if (size < READ_ONCE(up->forward_threshold) &&
1640	!skb_queue_empty(list: &up->reader_queue))
1641	return;
1642	} else {
1643	size += up->forward_deficit;
1644	}
1645	up->forward_deficit = `0`;
1646
1647	/ acquire the sk_receive_queue for fwd allocated memory scheduling,*
1648	* if the called don't held it already
1649	*/
1650	sk_queue = &sk->sk_receive_queue;
1651	if (!rx_queue_lock_held)
1652	spin_lock(lock: &sk_queue->lock);
1653
1654	amt = (size + sk->sk_forward_alloc - partial) & ~(PAGE_SIZE - `1`);
1655	sk_forward_alloc_add(sk, val: size - amt);
1656
1657	if (amt)
1658	__sk_mem_reduce_allocated(sk, amount: amt >> PAGE_SHIFT);
1659
1660	atomic_sub(i: size, v: &sk->sk_rmem_alloc);
1661
1662	/ this can save us from acquiring the rx queue lock on next receive /
1663	skb_queue_splice_tail_init(list: sk_queue, head: &up->reader_queue);
1664
1665	if (!rx_queue_lock_held)
1666	spin_unlock(lock: &sk_queue->lock);
1667	}
1668
1669	/ Note: called with reader_queue.lock held.*
1670	* Instead of using skb->truesize here, find a copy of it in skb->dev_scratch
1671	* This avoids a cache line miss while receive_queue lock is held.
1672	* Look at __udp_enqueue_schedule_skb() to find where this copy is done.
1673	*/
1674	void udp_skb_destructor(struct sock sk, struct* sk_buff *skb)
1675	{
1676	prefetch(&skb->data);
1677	udp_rmem_release(sk, size: udp_skb_truesize(skb), partial: `1`, rx_queue_lock_held: false);
1678	}
1679	EXPORT_IPV6_MOD(udp_skb_destructor);
1680
1681	/ as above, but the caller held the rx queue lock, too /
1682	static void udp_skb_dtor_locked(struct sock sk, struct* sk_buff *skb)
1683	{
1684	prefetch(&skb->data);
1685	udp_rmem_release(sk, size: udp_skb_truesize(skb), partial: `1`, rx_queue_lock_held: true);
1686	}
1687
1688	static int udp_rmem_schedule(struct sock sk, int* size)
1689	{
1690	int delta;
1691
1692	delta = size - sk->sk_forward_alloc;
1693	if (delta > `0` && !__sk_mem_schedule(sk, size: delta, SK_MEM_RECV))
1694	return -ENOBUFS;
1695
1696	return `0`;
1697	}
1698
1699	int __udp_enqueue_schedule_skb(struct sock sk, struct* sk_buff *skb)
1700	{
1701	struct sk_buff_head *list = &sk->sk_receive_queue;
1702	struct udp_prod_queue *udp_prod_queue;
1703	struct sk_buff next, to_drop = NULL;
1704	struct llist_node *ll_list;
1705	unsigned int rmem, rcvbuf;
1706	int size, err = -ENOMEM;
1707	int total_size = `0`;
1708	int q_size = `0`;
1709	int dropcount;
1710	int nb = `0`;
1711
1712	rmem = atomic_read(v: &sk->sk_rmem_alloc);
1713	rcvbuf = READ_ONCE(sk->sk_rcvbuf);
1714	size = skb->truesize;
1715
1716	udp_prod_queue = &udp_sk(sk)->udp_prod_queue[numa_node_id()];
1717
1718	rmem += atomic_read(v: &udp_prod_queue->rmem_alloc);
1719
1720	/ Immediately drop when the receive queue is full.*
1721	* Cast to unsigned int performs the boundary check for INT_MAX.
1722	*/
1723	if (rmem + size > rcvbuf) {
1724	if (rcvbuf > INT_MAX >> `1`)
1725	goto drop;
1726
1727	/ Accept the packet if queue is empty. /
1728	if (rmem)
1729	goto drop;
1730	}
1731
1732	/ Under mem pressure, it might be helpful to help udp_recvmsg()*
1733	* having linear skbs :
1734	* - Reduce memory overhead and thus increase receive queue capacity
1735	* - Less cache line misses at copyout() time
1736	* - Less work at consume_skb() (less alien page frag freeing)
1737	*/
1738	if (rmem > (rcvbuf >> `1`)) {
1739	skb_condense(skb);
1740	size = skb->truesize;
1741	}
1742
1743	udp_set_dev_scratch(skb);
1744
1745	atomic_add(i: size, v: &udp_prod_queue->rmem_alloc);
1746
1747	if (!llist_add(new: &skb->ll_node, head: &udp_prod_queue->ll_root))
1748	return `0`;
1749
1750	dropcount = sock_flag(sk, flag: SOCK_RXQ_OVFL) ? sk_drops_read(sk) : `0`;
1751
1752	spin_lock(lock: &list->lock);
1753
1754	ll_list = llist_del_all(head: &udp_prod_queue->ll_root);
1755
1756	ll_list = llist_reverse_order(head: ll_list);
1757
1758	llist_for_each_entry_safe(skb, next, ll_list, ll_node) {
1759	size = udp_skb_truesize(skb);
1760	total_size += size;
1761	err = udp_rmem_schedule(sk, size);
1762	if (unlikely(err)) {
1763	/ Free the skbs outside of locked section. /
1764	skb->next = to_drop;
1765	to_drop = skb;
1766	continue;
1767	}
1768
1769	q_size += size;
1770	sk_forward_alloc_add(sk, val: -size);
1771
1772	/ no need to setup a destructor, we will explicitly release the*
1773	* forward allocated memory on dequeue
1774	*/
1775	SOCK_SKB_CB(skb)->dropcount = dropcount;
1776	nb++;
1777	__skb_queue_tail(list, newsk: skb);
1778	}
1779
1780	atomic_add(i: q_size, v: &sk->sk_rmem_alloc);
1781
1782	spin_unlock(lock: &list->lock);
1783
1784	if (!sock_flag(sk, flag: SOCK_DEAD)) {
1785	/ Multiple threads might be blocked in recvmsg(),*
1786	* using prepare_to_wait_exclusive().
1787	*/
1788	while (nb) {
1789	INDIRECT_CALL_1(sk->sk_data_ready,
1790	sock_def_readable, sk);
1791	nb--;
1792	}
1793	}
1794
1795	if (unlikely(to_drop)) {
1796	for (nb = `0`; to_drop != NULL; nb++) {
1797	skb = to_drop;
1798	to_drop = skb->next;
1799	skb_mark_not_on_list(skb);
1800	/ TODO: update SNMP values. /
1801	sk_skb_reason_drop(sk, skb, reason: SKB_DROP_REASON_PROTO_MEM);
1802	}
1803	numa_drop_add(ndc: &udp_sk(sk)->drop_counters, val: nb);
1804	}
1805
1806	atomic_sub(i: total_size, v: &udp_prod_queue->rmem_alloc);
1807
1808	return `0`;
1809
1810	drop:
1811	udp_drops_inc(sk);
1812	return err;
1813	}
1814	EXPORT_IPV6_MOD_GPL(__udp_enqueue_schedule_skb);
1815
1816	void udp_destruct_common(struct sock *sk)
1817	{
1818	/ reclaim completely the forward allocated memory /
1819	struct udp_sock *up = udp_sk(sk);
1820	unsigned int total = `0`;
1821	struct sk_buff *skb;
1822
1823	skb_queue_splice_tail_init(list: &sk->sk_receive_queue, head: &up->reader_queue);
1824	while ((skb = __skb_dequeue(list: &up->reader_queue)) != NULL) {
1825	total += skb->truesize;
1826	kfree_skb(skb);
1827	}
1828	udp_rmem_release(sk, size: total, partial: `0`, rx_queue_lock_held: true);
1829	kfree(objp: up->udp_prod_queue);
1830	}
1831	EXPORT_IPV6_MOD_GPL(udp_destruct_common);
1832
1833	static void udp_destruct_sock(struct sock *sk)
1834	{
1835	udp_destruct_common(sk);
1836	inet_sock_destruct(sk);
1837	}
1838
1839	int udp_init_sock(struct sock *sk)
1840	{
1841	int res = udp_lib_init_sock(sk);
1842
1843	sk->sk_destruct = udp_destruct_sock;
1844	set_bit(nr: SOCK_SUPPORT_ZC, addr: &sk->sk_socket->flags);
1845	return res;
1846	}
1847
1848	void skb_consume_udp(struct sock sk, struct* sk_buff skb, int* len)
1849	{
1850	if (unlikely(READ_ONCE(udp_sk(sk)->peeking_with_offset)))
1851	sk_peek_offset_bwd(sk, val: len);
1852
1853	if (!skb_shared(skb)) {
1854	if (unlikely(udp_skb_has_head_state(skb)))
1855	skb_release_head_state(skb);
1856	skb_attempt_defer_free(skb);
1857	return;
1858	}
1859
1860	if (!skb_unref(skb))
1861	return;
1862
1863	/ In the more common cases we cleared the head states previously,*
1864	* see __udp_queue_rcv_skb().
1865	*/
1866	if (unlikely(udp_skb_has_head_state(skb)))
1867	skb_release_head_state(skb);
1868	__consume_stateless_skb(skb);
1869	}
1870	EXPORT_IPV6_MOD_GPL(skb_consume_udp);
1871
1872	static struct sk_buff __first_packet_length(struct* sock *sk,
1873	struct sk_buff_head *rcvq,
1874	unsigned int *total)
1875	{
1876	struct sk_buff *skb;
1877
1878	while ((skb = skb_peek(list_: rcvq)) != NULL) {
1879	if (udp_lib_checksum_complete(skb)) {
1880	__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS,
1881	IS_UDPLITE(sk));
1882	__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
1883	IS_UDPLITE(sk));
1884	udp_drops_inc(sk);
1885	__skb_unlink(skb, list: rcvq);
1886	*total += skb->truesize;
1887	kfree_skb_reason(skb, reason: SKB_DROP_REASON_UDP_CSUM);
1888	} else {
1889	udp_skb_csum_unnecessary_set(skb);
1890	break;
1891	}
1892	}
1893	return skb;
1894	}
1895
1896	/**
1897	* first_packet_length - return length of first packet in receive queue
1898	* @sk: socket
1899	*
1900	* Drops all bad checksum frames, until a valid one is found.
1901	* Returns the length of found skb, or -1 if none is found.
1902	*/
1903	static int first_packet_length(struct sock *sk)
1904	{
1905	struct sk_buff_head *rcvq = &udp_sk(sk)->reader_queue;
1906	struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
1907	unsigned int total = `0`;
1908	struct sk_buff *skb;
1909	int res;
1910
1911	spin_lock_bh(lock: &rcvq->lock);
1912	skb = __first_packet_length(sk, rcvq, total: &total);
1913	if (!skb && !skb_queue_empty_lockless(list: sk_queue)) {
1914	spin_lock(lock: &sk_queue->lock);
1915	skb_queue_splice_tail_init(list: sk_queue, head: rcvq);
1916	spin_unlock(lock: &sk_queue->lock);
1917
1918	skb = __first_packet_length(sk, rcvq, total: &total);
1919	}
1920	res = skb ? skb->len : -`1`;
1921	if (total)
1922	udp_rmem_release(sk, size: total, partial: `1`, rx_queue_lock_held: false);
1923	spin_unlock_bh(lock: &rcvq->lock);
1924	return res;
1925	}
1926
1927	/*
1928	* IOCTL requests applicable to the UDP protocol
1929	*/
1930
1931	int udp_ioctl(struct sock sk, int* cmd, int *karg)
1932	{
1933	switch (cmd) {
1934	case SIOCOUTQ:
1935	{
1936	*karg = sk_wmem_alloc_get(sk);
1937	return `0`;
1938	}
1939
1940	case SIOCINQ:
1941	{
1942	karg = max_t(int*, `0`, first_packet_length(sk));
1943	return `0`;
1944	}
1945
1946	default:
1947	return -ENOIOCTLCMD;
1948	}
1949
1950	return `0`;
1951	}
1952	EXPORT_IPV6_MOD(udp_ioctl);
1953
1954	struct sk_buff __skb_recv_udp(struct* sock sk, unsigned* int flags,
1955	int off, int* *err)
1956	{
1957	struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
1958	struct sk_buff_head *queue;
1959	struct sk_buff *last;
1960	long timeo;
1961	int error;
1962
1963	queue = &udp_sk(sk)->reader_queue;
1964	timeo = sock_rcvtimeo(sk, noblock: flags & MSG_DONTWAIT);
1965	do {
1966	struct sk_buff *skb;
1967
1968	error = sock_error(sk);
1969	if (error)
1970	break;
1971
1972	error = -EAGAIN;
1973	do {
1974	spin_lock_bh(lock: &queue->lock);
1975	skb = __skb_try_recv_from_queue(queue, flags, off, err,
1976	last: &last);
1977	if (skb) {
1978	if (!(flags & MSG_PEEK))
1979	udp_skb_destructor(sk, skb);
1980	spin_unlock_bh(lock: &queue->lock);
1981	return skb;
1982	}
1983
1984	if (skb_queue_empty_lockless(list: sk_queue)) {
1985	spin_unlock_bh(lock: &queue->lock);
1986	goto busy_check;
1987	}
1988
1989	/ refill the reader queue and walk it again*
1990	* keep both queues locked to avoid re-acquiring
1991	* the sk_receive_queue lock if fwd memory scheduling
1992	* is needed.
1993	*/
1994	spin_lock(lock: &sk_queue->lock);
1995	skb_queue_splice_tail_init(list: sk_queue, head: queue);
1996
1997	skb = __skb_try_recv_from_queue(queue, flags, off, err,
1998	last: &last);
1999	if (skb && !(flags & MSG_PEEK))
2000	udp_skb_dtor_locked(sk, skb);
2001	spin_unlock(lock: &sk_queue->lock);
2002	spin_unlock_bh(lock: &queue->lock);
2003	if (skb)
2004	return skb;
2005
2006	busy_check:
2007	if (!sk_can_busy_loop(sk))
2008	break;
2009
2010	sk_busy_loop(sk, nonblock: flags & MSG_DONTWAIT);
2011	} while (!skb_queue_empty_lockless(list: sk_queue));
2012
2013	/ sk_queue is empty, reader_queue may contain peeked packets /
2014	} while (timeo &&
2015	!__skb_wait_for_more_packets(sk, queue: &sk->sk_receive_queue,
2016	err: &error, timeo_p: &timeo,
2017	skb: (struct sk_buff *)sk_queue));
2018
2019	*err = error;
2020	return NULL;
2021	}
2022	EXPORT_SYMBOL(__skb_recv_udp);
2023
2024	int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
2025	{
2026	struct sk_buff *skb;
2027	int err;
2028
2029	try_again:
2030	skb = skb_recv_udp(sk, MSG_DONTWAIT, err: &err);
2031	if (!skb)
2032	return err;
2033
2034	if (udp_lib_checksum_complete(skb)) {
2035	int is_udplite = IS_UDPLITE(sk);
2036	struct net *net = sock_net(sk);
2037
2038	__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, is_udplite);
2039	__UDP_INC_STATS(net, UDP_MIB_INERRORS, is_udplite);
2040	udp_drops_inc(sk);
2041	kfree_skb_reason(skb, reason: SKB_DROP_REASON_UDP_CSUM);
2042	goto try_again;
2043	}
2044
2045	WARN_ON_ONCE(!skb_set_owner_sk_safe(skb, sk));
2046	return recv_actor(sk, skb);
2047	}
2048	EXPORT_IPV6_MOD(udp_read_skb);
2049
2050	/*
2051	* This should be easy, if there is something there we
2052	* return it, otherwise we block.
2053	*/
2054
2055	int udp_recvmsg(struct sock sk, struct* msghdr msg, size_t len, int* flags,
2056	int *addr_len)
2057	{
2058	struct inet_sock *inet = inet_sk(sk);
2059	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
2060	struct sk_buff *skb;
2061	unsigned int ulen, copied;
2062	int off, err, peeking = flags & MSG_PEEK;
2063	int is_udplite = IS_UDPLITE(sk);
2064	bool checksum_valid = false;
2065
2066	if (flags & MSG_ERRQUEUE)
2067	return ip_recv_error(sk, msg, len, addr_len);
2068
2069	try_again:
2070	off = sk_peek_offset(sk, flags);
2071	skb = __skb_recv_udp(sk, flags, &off, &err);
2072	if (!skb)
2073	return err;
2074
2075	ulen = udp_skb_len(skb);
2076	copied = len;
2077	if (copied > ulen - off)
2078	copied = ulen - off;
2079	else if (copied < ulen)
2080	msg->msg_flags \|= MSG_TRUNC;
2081
2082	/*
2083	* If checksum is needed at all, try to do it while copying the
2084	* data. If the data is truncated, or if we only want a partial
2085	* coverage checksum (UDP-Lite), do it before the copy.
2086	*/
2087
2088	if (copied < ulen \|\| peeking \|\|
2089	(is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
2090	checksum_valid = udp_skb_csum_unnecessary(skb) \|\|
2091	!__udp_lib_checksum_complete(skb);
2092	if (!checksum_valid)
2093	goto csum_copy_err;
2094	}
2095
2096	if (checksum_valid \|\| udp_skb_csum_unnecessary(skb)) {
2097	if (udp_skb_is_linear(skb))
2098	err = copy_linear_skb(skb, len: copied, off, to: &msg->msg_iter);
2099	else
2100	err = skb_copy_datagram_msg(from: skb, offset: off, msg, size: copied);
2101	} else {
2102	err = skb_copy_and_csum_datagram_msg(skb, hlen: off, msg);
2103
2104	if (err == -EINVAL)
2105	goto csum_copy_err;
2106	}
2107
2108	if (unlikely(err)) {
2109	if (!peeking) {
2110	udp_drops_inc(sk);
2111	UDP_INC_STATS(sock_net(sk),
2112	UDP_MIB_INERRORS, is_udplite);
2113	}
2114	kfree_skb(skb);
2115	return err;
2116	}
2117
2118	if (!peeking)
2119	UDP_INC_STATS(sock_net(sk),
2120	UDP_MIB_INDATAGRAMS, is_udplite);
2121
2122	sock_recv_cmsgs(msg, sk, skb);
2123
2124	/ Copy the address. /
2125	if (sin) {
2126	sin->sin_family = AF_INET;
2127	sin->sin_port = udp_hdr(skb)->source;
2128	sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
2129	memset(s: sin->sin_zero, c: `0`, n: sizeof(sin->sin_zero));
2130	addr_len = sizeof(sin);
2131
2132	BPF_CGROUP_RUN_PROG_UDP4_RECVMSG_LOCK(sk,
2133	(struct sockaddr *)sin,
2134	addr_len);
2135	}
2136
2137	if (udp_test_bit(GRO_ENABLED, sk))
2138	udp_cmsg_recv(msg, sk, skb);
2139
2140	if (inet_cmsg_flags(inet))
2141	ip_cmsg_recv_offset(msg, sk, skb, tlen: sizeof(struct udphdr), offset: off);
2142
2143	err = copied;
2144	if (flags & MSG_TRUNC)
2145	err = ulen;
2146
2147	skb_consume_udp(sk, skb, len: peeking ? -err : err);
2148	return err;
2149
2150	csum_copy_err:
2151	if (!__sk_queue_drop_skb(sk, sk_queue: &udp_sk(sk)->reader_queue, skb, flags,
2152	destructor: udp_skb_destructor)) {
2153	UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
2154	UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
2155	}
2156	kfree_skb_reason(skb, reason: SKB_DROP_REASON_UDP_CSUM);
2157
2158	/ starting over for a new packet, but check if we need to yield /
2159	cond_resched();
2160	msg->msg_flags &= ~MSG_TRUNC;
2161	goto try_again;
2162	}
2163
2164	int udp_pre_connect(struct sock sk, struct* sockaddr uaddr, int* addr_len)
2165	{
2166	/ This check is replicated from __ip4_datagram_connect() and*
2167	* intended to prevent BPF program called below from accessing bytes
2168	* that are out of the bound specified by user in addr_len.
2169	*/
2170	if (addr_len < sizeof(struct sockaddr_in))
2171	return -EINVAL;
2172
2173	return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr, &addr_len);
2174	}
2175	EXPORT_IPV6_MOD(udp_pre_connect);
2176
2177	static int udp_connect(struct sock sk, struct* sockaddr uaddr, int* addr_len)
2178	{
2179	int res;
2180
2181	lock_sock(sk);
2182	res = __ip4_datagram_connect(sk, uaddr, addr_len);
2183	if (!res)
2184	udp4_hash4(sk);
2185	release_sock(sk);
2186	return res;
2187	}
2188
2189	int __udp_disconnect(struct sock sk, int* flags)
2190	{
2191	struct inet_sock *inet = inet_sk(sk);
2192	/*
2193	* 1003.1g - break association.
2194	*/
2195
2196	sk->sk_state = TCP_CLOSE;
2197	inet->inet_daddr = `0`;
2198	inet->inet_dport = `0`;
2199	sock_rps_reset_rxhash(sk);
2200	sk->sk_bound_dev_if = `0`;
2201	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK)) {
2202	inet_reset_saddr(sk);
2203	if (sk->sk_prot->rehash &&
2204	(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
2205	sk->sk_prot->rehash(sk);
2206	}
2207
2208	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
2209	sk->sk_prot->unhash(sk);
2210	inet->inet_sport = `0`;
2211	}
2212	sk_dst_reset(sk);
2213	return `0`;
2214	}
2215	EXPORT_SYMBOL(__udp_disconnect);
2216
2217	int udp_disconnect(struct sock sk, int* flags)
2218	{
2219	lock_sock(sk);
2220	__udp_disconnect(sk, flags);
2221	release_sock(sk);
2222	return `0`;
2223	}
2224	EXPORT_IPV6_MOD(udp_disconnect);
2225
2226	void udp_lib_unhash(struct sock *sk)
2227	{
2228	if (sk_hashed(sk)) {
2229	struct udp_table *udptable = udp_get_table_prot(sk);
2230	struct udp_hslot hslot, hslot2;
2231
2232	sock_rps_delete_flow(sk);
2233	hslot = udp_hashslot(table: udptable, net: sock_net(sk),
2234	udp_sk(sk)->udp_port_hash);
2235	hslot2 = udp_hashslot2(table: udptable, udp_sk(sk)->udp_portaddr_hash);
2236
2237	spin_lock_bh(lock: &hslot->lock);
2238	if (rcu_access_pointer(sk->sk_reuseport_cb))
2239	reuseport_detach_sock(sk);
2240	if (sk_del_node_init_rcu(sk)) {
2241	hslot->count--;
2242	inet_sk(sk)->inet_num = `0`;
2243	sock_prot_inuse_add(net: sock_net(sk), prot: sk->sk_prot, val: -`1`);
2244
2245	spin_lock(lock: &hslot2->lock);
2246	hlist_del_init_rcu(n: &udp_sk(sk)->udp_portaddr_node);
2247	hslot2->count--;
2248	spin_unlock(lock: &hslot2->lock);
2249
2250	udp_unhash4(udptable, sk);
2251	}
2252	spin_unlock_bh(lock: &hslot->lock);
2253	}
2254	}
2255	EXPORT_IPV6_MOD(udp_lib_unhash);
2256
2257	/*
2258	* inet_rcv_saddr was changed, we must rehash secondary hash
2259	*/
2260	void udp_lib_rehash(struct sock *sk, u16 newhash, u16 newhash4)
2261	{
2262	if (sk_hashed(sk)) {
2263	struct udp_table *udptable = udp_get_table_prot(sk);
2264	struct udp_hslot hslot, hslot2, *nhslot2;
2265
2266	hslot = udp_hashslot(table: udptable, net: sock_net(sk),
2267	udp_sk(sk)->udp_port_hash);
2268	hslot2 = udp_hashslot2(table: udptable, udp_sk(sk)->udp_portaddr_hash);
2269	nhslot2 = udp_hashslot2(table: udptable, hash: newhash);
2270	udp_sk(sk)->udp_portaddr_hash = newhash;
2271
2272	if (hslot2 != nhslot2 \|\|
2273	rcu_access_pointer(sk->sk_reuseport_cb)) {
2274	/ we must lock primary chain too /
2275	spin_lock_bh(lock: &hslot->lock);
2276	if (rcu_access_pointer(sk->sk_reuseport_cb))
2277	reuseport_detach_sock(sk);
2278
2279	if (hslot2 != nhslot2) {
2280	spin_lock(lock: &hslot2->lock);
2281	hlist_del_init_rcu(n: &udp_sk(sk)->udp_portaddr_node);
2282	hslot2->count--;
2283	spin_unlock(lock: &hslot2->lock);
2284
2285	spin_lock(lock: &nhslot2->lock);
2286	hlist_add_head_rcu(n: &udp_sk(sk)->udp_portaddr_node,
2287	h: &nhslot2->head);
2288	nhslot2->count++;
2289	spin_unlock(lock: &nhslot2->lock);
2290	}
2291
2292	spin_unlock_bh(lock: &hslot->lock);
2293	}
2294
2295	/ Now process hash4 if necessary:*
2296	* (1) update hslot4;
2297	* (2) update hslot2->hash4_cnt.
2298	* Note that hslot2/hslot4 should be checked separately, as
2299	* either of them may change with the other unchanged.
2300	*/
2301	if (udp_hashed4(sk)) {
2302	spin_lock_bh(lock: &hslot->lock);
2303
2304	udp_rehash4(udptable, sk, newhash4);
2305	if (hslot2 != nhslot2) {
2306	spin_lock(lock: &hslot2->lock);
2307	udp_hash4_dec(hslot2);
2308	spin_unlock(lock: &hslot2->lock);
2309
2310	spin_lock(lock: &nhslot2->lock);
2311	udp_hash4_inc(hslot2: nhslot2);
2312	spin_unlock(lock: &nhslot2->lock);
2313	}
2314
2315	spin_unlock_bh(lock: &hslot->lock);
2316	}
2317	}
2318	}
2319	EXPORT_IPV6_MOD(udp_lib_rehash);
2320
2321	void udp_v4_rehash(struct sock *sk)
2322	{
2323	u16 new_hash = ipv4_portaddr_hash(net: sock_net(sk),
2324	inet_sk(sk)->inet_rcv_saddr,
2325	inet_sk(sk)->inet_num);
2326	u16 new_hash4 = udp_ehashfn(net: sock_net(sk),
2327	laddr: sk->sk_rcv_saddr, lport: sk->sk_num,
2328	faddr: sk->sk_daddr, fport: sk->sk_dport);
2329
2330	udp_lib_rehash(sk, newhash: new_hash, newhash4: new_hash4);
2331	}
2332
2333	static int __udp_queue_rcv_skb(struct sock sk, struct* sk_buff *skb)
2334	{
2335	int rc;
2336
2337	if (inet_sk(sk)->inet_daddr) {
2338	sock_rps_save_rxhash(sk, skb);
2339	sk_mark_napi_id(sk, skb);
2340	sk_incoming_cpu_update(sk);
2341	} else {
2342	sk_mark_napi_id_once(sk, skb);
2343	}
2344
2345	rc = __udp_enqueue_schedule_skb(sk, skb);
2346	if (rc < `0`) {
2347	int is_udplite = IS_UDPLITE(sk);
2348	int drop_reason;
2349
2350	/ Note that an ENOMEM error is charged twice /
2351	if (rc == -ENOMEM) {
2352	UDP_INC_STATS(sock_net(sk), UDP_MIB_RCVBUFERRORS,
2353	is_udplite);
2354	drop_reason = SKB_DROP_REASON_SOCKET_RCVBUFF;
2355	} else {
2356	UDP_INC_STATS(sock_net(sk), UDP_MIB_MEMERRORS,
2357	is_udplite);
2358	drop_reason = SKB_DROP_REASON_PROTO_MEM;
2359	}
2360	UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
2361	trace_udp_fail_queue_rcv_skb(rc, sk, skb);
2362	sk_skb_reason_drop(sk, skb, reason: drop_reason);
2363	return -`1`;
2364	}
2365
2366	return `0`;
2367	}
2368
2369	/ returns:*
2370	* -1: error
2371	* 0: success
2372	* >0: "udp encap" protocol resubmission
2373	*
2374	* Note that in the success and error cases, the skb is assumed to
2375	* have either been requeued or freed.
2376	*/
2377	static int udp_queue_rcv_one_skb(struct sock sk, struct* sk_buff *skb)
2378	{
2379	enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2380	struct udp_sock *up = udp_sk(sk);
2381	int is_udplite = IS_UDPLITE(sk);
2382
2383	/*
2384	* Charge it to the socket, dropping if the queue is full.
2385	*/
2386	if (!xfrm4_policy_check(sk, dir: XFRM_POLICY_IN, skb)) {
2387	drop_reason = SKB_DROP_REASON_XFRM_POLICY;
2388	goto drop;
2389	}
2390	nf_reset_ct(skb);
2391
2392	if (static_branch_unlikely(&udp_encap_needed_key) &&
2393	READ_ONCE(up->encap_type)) {
2394	int (encap_rcv)(struct* sock sk, struct* sk_buff *skb);
2395
2396	/*
2397	* This is an encapsulation socket so pass the skb to
2398	* the socket's udp_encap_rcv() hook. Otherwise, just
2399	* fall through and pass this up the UDP socket.
2400	* up->encap_rcv() returns the following value:
2401	* =0 if skb was successfully passed to the encap
2402	* handler or was discarded by it.
2403	* >0 if skb should be passed on to UDP.
2404	* <0 if skb should be resubmitted as proto -N
2405	*/
2406
2407	/ if we're overly short, let UDP handle it /
2408	encap_rcv = READ_ONCE(up->encap_rcv);
2409	if (encap_rcv) {
2410	int ret;
2411
2412	/ Verify checksum before giving to encap /
2413	if (udp_lib_checksum_complete(skb))
2414	goto csum_error;
2415
2416	ret = encap_rcv(sk, skb);
2417	if (ret <= `0`) {
2418	__UDP_INC_STATS(sock_net(sk),
2419	UDP_MIB_INDATAGRAMS,
2420	is_udplite);
2421	return -ret;
2422	}
2423	}
2424
2425	/ FALLTHROUGH -- it's a UDP Packet /
2426	}
2427
2428	/*
2429	* UDP-Lite specific tests, ignored on UDP sockets
2430	*/
2431	if (udp_test_bit(UDPLITE_RECV_CC, sk) && UDP_SKB_CB(skb)->partial_cov) {
2432	u16 pcrlen = READ_ONCE(up->pcrlen);
2433
2434	/*
2435	* MIB statistics other than incrementing the error count are
2436	* disabled for the following two types of errors: these depend
2437	* on the application settings, not on the functioning of the
2438	* protocol stack as such.
2439	*
2440	* RFC 3828 here recommends (sec 3.3): "There should also be a
2441	* way ... to ... at least let the receiving application block
2442	* delivery of packets with coverage values less than a value
2443	* provided by the application."
2444	*/
2445	if (pcrlen == `0`) { / full coverage was set /
2446	net_dbg_ratelimited("UDPLite: partial coverage %d while full coverage %d requested\n",
2447	UDP_SKB_CB(skb)->cscov, skb->len);
2448	goto drop;
2449	}
2450	/ The next case involves violating the min. coverage requested*
2451	* by the receiver. This is subtle: if receiver wants x and x is
2452	* greater than the buffersize/MTU then receiver will complain
2453	* that it wants x while sender emits packets of smaller size y.
2454	* Therefore the above ...()->partial_cov statement is essential.
2455	*/
2456	if (UDP_SKB_CB(skb)->cscov < pcrlen) {
2457	net_dbg_ratelimited("UDPLite: coverage %d too small, need min %d\n",
2458	UDP_SKB_CB(skb)->cscov, pcrlen);
2459	goto drop;
2460	}
2461	}
2462
2463	prefetch(&sk->sk_rmem_alloc);
2464	if (rcu_access_pointer(sk->sk_filter) &&
2465	udp_lib_checksum_complete(skb))
2466	goto csum_error;
2467
2468	if (sk_filter_trim_cap(sk, skb, cap: sizeof(struct udphdr), reason: &drop_reason))
2469	goto drop;
2470
2471	udp_csum_pull_header(skb);
2472
2473	ipv4_pktinfo_prepare(sk, skb, drop_dst: true);
2474	return __udp_queue_rcv_skb(sk, skb);
2475
2476	csum_error:
2477	drop_reason = SKB_DROP_REASON_UDP_CSUM;
2478	__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
2479	drop:
2480	__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
2481	udp_drops_inc(sk);
2482	sk_skb_reason_drop(sk, skb, reason: drop_reason);
2483	return -`1`;
2484	}
2485
2486	static int udp_queue_rcv_skb(struct sock sk, struct* sk_buff *skb)
2487	{
2488	struct sk_buff next, segs;
2489	int ret;
2490
2491	if (likely(!udp_unexpected_gso(sk, skb)))
2492	return udp_queue_rcv_one_skb(sk, skb);
2493
2494	BUILD_BUG_ON(sizeof(struct udp_skb_cb) > SKB_GSO_CB_OFFSET);
2495	__skb_push(skb, len: -skb_mac_offset(skb));
2496	segs = udp_rcv_segment(sk, skb, ipv4: true);
2497	skb_list_walk_safe(segs, skb, next) {
2498	__skb_pull(skb, len: skb_transport_offset(skb));
2499
2500	udp_post_segment_fix_csum(skb);
2501	ret = udp_queue_rcv_one_skb(sk, skb);
2502	if (ret > `0`)
2503	ip_protocol_deliver_rcu(net: dev_net(dev: skb->dev), skb, proto: ret);
2504	}
2505	return `0`;
2506	}
2507
2508	/ For TCP sockets, sk_rx_dst is protected by socket lock*
2509	* For UDP, we use xchg() to guard against concurrent changes.
2510	*/
2511	bool udp_sk_rx_dst_set(struct sock sk, struct* dst_entry *dst)
2512	{
2513	struct dst_entry *old;
2514
2515	if (dst_hold_safe(dst)) {
2516	old = unrcu_pointer(xchg(&sk->sk_rx_dst, RCU_INITIALIZER(dst)));
2517	dst_release(dst: old);
2518	return old != dst;
2519	}
2520	return false;
2521	}
2522	EXPORT_IPV6_MOD(udp_sk_rx_dst_set);
2523
2524	/*
2525	* Multicasts and broadcasts go to each listener.
2526	*
2527	* Note: called only from the BH handler context.
2528	*/
2529	static int __udp4_lib_mcast_deliver(struct net net, struct* sk_buff *skb,
2530	struct udphdr *uh,
2531	__be32 saddr, __be32 daddr,
2532	struct udp_table *udptable,
2533	int proto)
2534	{
2535	struct sock sk, first = NULL;
2536	unsigned short hnum = ntohs(uh->dest);
2537	struct udp_hslot *hslot = udp_hashslot(table: udptable, net, num: hnum);
2538	unsigned int hash2 = `0`, hash2_any = `0`, use_hash2 = (hslot->count > `10`);
2539	unsigned int offset = offsetof(typeof(*sk), sk_node);
2540	int dif = skb->dev->ifindex;
2541	int sdif = inet_sdif(skb);
2542	struct hlist_node *node;
2543	struct sk_buff *nskb;
2544
2545	if (use_hash2) {
2546	hash2_any = ipv4_portaddr_hash(net, htonl(INADDR_ANY), port: hnum) &
2547	udptable->mask;
2548	hash2 = ipv4_portaddr_hash(net, saddr: daddr, port: hnum) & udptable->mask;
2549	start_lookup:
2550	hslot = &udptable->hash2[hash2].hslot;
2551	offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
2552	}
2553
2554	sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
2555	if (!__udp_is_mcast_sock(net, sk, loc_port: uh->dest, loc_addr: daddr,
2556	rmt_port: uh->source, rmt_addr: saddr, dif, sdif, hnum))
2557	continue;
2558
2559	if (!first) {
2560	first = sk;
2561	continue;
2562	}
2563	nskb = skb_clone(skb, GFP_ATOMIC);
2564
2565	if (unlikely(!nskb)) {
2566	udp_drops_inc(sk);
2567	__UDP_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
2568	IS_UDPLITE(sk));
2569	__UDP_INC_STATS(net, UDP_MIB_INERRORS,
2570	IS_UDPLITE(sk));
2571	continue;
2572	}
2573	if (udp_queue_rcv_skb(sk, skb: nskb) > `0`)
2574	consume_skb(skb: nskb);
2575	}
2576
2577	/ Also lookup :port if we are using hash2 and haven't done so yet. /*
2578	if (use_hash2 && hash2 != hash2_any) {
2579	hash2 = hash2_any;
2580	goto start_lookup;
2581	}
2582
2583	if (first) {
2584	if (udp_queue_rcv_skb(sk: first, skb) > `0`)
2585	consume_skb(skb);
2586	} else {
2587	kfree_skb(skb);
2588	__UDP_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
2589	proto == IPPROTO_UDPLITE);
2590	}
2591	return `0`;
2592	}
2593
2594	/ Initialize UDP checksum. If exited with zero value (success),*
2595	* CHECKSUM_UNNECESSARY means, that no more checks are required.
2596	* Otherwise, csum completion requires checksumming packet body,
2597	* including udp header and folding it to skb->csum.
2598	*/
2599	static inline int udp4_csum_init(struct sk_buff skb, struct* udphdr *uh,
2600	int proto)
2601	{
2602	int err;
2603
2604	UDP_SKB_CB(skb)->partial_cov = `0`;
2605	UDP_SKB_CB(skb)->cscov = skb->len;
2606
2607	if (proto == IPPROTO_UDPLITE) {
2608	err = udplite_checksum_init(skb, uh);
2609	if (err)
2610	return err;
2611
2612	if (UDP_SKB_CB(skb)->partial_cov) {
2613	skb->csum = inet_compute_pseudo(skb, proto);
2614	return `0`;
2615	}
2616	}
2617
2618	/ Note, we are only interested in != 0 or == 0, thus the*
2619	* force to int.
2620	*/
2621	err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
2622	inet_compute_pseudo);
2623	if (err)
2624	return err;
2625
2626	if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
2627	/ If SW calculated the value, we know it's bad /
2628	if (skb->csum_complete_sw)
2629	return `1`;
2630
2631	/ HW says the value is bad. Let's validate that.*
2632	* skb->csum is no longer the full packet checksum,
2633	* so don't treat it as such.
2634	*/
2635	skb_checksum_complete_unset(skb);
2636	}
2637
2638	return `0`;
2639	}
2640
2641	/ wrapper for udp_queue_rcv_skb taking care of csum conversion and*
2642	* return code conversion for ip layer consumption
2643	*/
2644	static int udp_unicast_rcv_skb(struct sock sk, struct* sk_buff *skb,
2645	struct udphdr *uh)
2646	{
2647	int ret;
2648
2649	if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
2650	skb_checksum_try_convert(skb, IPPROTO_UDP, inet_compute_pseudo);
2651
2652	ret = udp_queue_rcv_skb(sk, skb);
2653
2654	/ a return value > 0 means to resubmit the input, but*
2655	* it wants the return to be -protocol, or 0
2656	*/
2657	if (ret > `0`)
2658	return -ret;
2659	return `0`;
2660	}
2661
2662	/*
2663	* All we need to do is get the socket, and then do a checksum.
2664	*/
2665
2666	int __udp4_lib_rcv(struct sk_buff skb, struct* udp_table *udptable,
2667	int proto)
2668	{
2669	struct sock *sk = NULL;
2670	struct udphdr *uh;
2671	unsigned short ulen;
2672	struct rtable *rt = skb_rtable(skb);
2673	__be32 saddr, daddr;
2674	struct net *net = dev_net(dev: skb->dev);
2675	bool refcounted;
2676	int drop_reason;
2677
2678	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
2679
2680	/*
2681	* Validate the packet.
2682	*/
2683	if (!pskb_may_pull(skb, len: sizeof(struct udphdr)))
2684	goto drop; / No space for header. /
2685
2686	uh = udp_hdr(skb);
2687	ulen = ntohs(uh->len);
2688	saddr = ip_hdr(skb)->saddr;
2689	daddr = ip_hdr(skb)->daddr;
2690
2691	if (ulen > skb->len)
2692	goto short_packet;
2693
2694	if (proto == IPPROTO_UDP) {
2695	/ UDP validates ulen. /
2696	if (ulen < sizeof(*uh) \|\| pskb_trim_rcsum(skb, len: ulen))
2697	goto short_packet;
2698	uh = udp_hdr(skb);
2699	}
2700
2701	if (udp4_csum_init(skb, uh, proto))
2702	goto csum_error;
2703
2704	sk = inet_steal_sock(net, skb, doff: sizeof(struct udphdr), saddr, sport: uh->source, daddr, dport: uh->dest,
2705	refcounted: &refcounted, ehashfn: udp_ehashfn);
2706	if (IS_ERR(ptr: sk))
2707	goto no_sk;
2708
2709	if (sk) {
2710	struct dst_entry *dst = skb_dst(skb);
2711	int ret;
2712
2713	if (unlikely(rcu_dereference(sk->sk_rx_dst) != dst))
2714	udp_sk_rx_dst_set(sk, dst);
2715
2716	ret = udp_unicast_rcv_skb(sk, skb, uh);
2717	if (refcounted)
2718	sock_put(sk);
2719	return ret;
2720	}
2721
2722	if (rt->rt_flags & (RTCF_BROADCAST\|RTCF_MULTICAST))
2723	return __udp4_lib_mcast_deliver(net, skb, uh,
2724	saddr, daddr, udptable, proto);
2725
2726	sk = __udp4_lib_lookup_skb(skb, sport: uh->source, dport: uh->dest, udptable);
2727	if (sk)
2728	return udp_unicast_rcv_skb(sk, skb, uh);
2729	no_sk:
2730	if (!xfrm4_policy_check(NULL, dir: XFRM_POLICY_IN, skb))
2731	goto drop;
2732	nf_reset_ct(skb);
2733
2734	/ No socket. Drop packet silently, if checksum is wrong /
2735	if (udp_lib_checksum_complete(skb))
2736	goto csum_error;
2737
2738	drop_reason = SKB_DROP_REASON_NO_SOCKET;
2739	__UDP_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
2740	icmp_send(skb_in: skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, info: `0`);
2741
2742	/*
2743	* Hmm. We got an UDP packet to a port to which we
2744	* don't wanna listen. Ignore it.
2745	*/
2746	sk_skb_reason_drop(sk, skb, reason: drop_reason);
2747	return `0`;
2748
2749	short_packet:
2750	drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
2751	net_dbg_ratelimited("UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
2752	proto == IPPROTO_UDPLITE ? "Lite" : "",
2753	&saddr, ntohs(uh->source),
2754	ulen, skb->len,
2755	&daddr, ntohs(uh->dest));
2756	goto drop;
2757
2758	csum_error:
2759	/*
2760	* RFC1122: OK. Discards the bad packet silently (as far as
2761	* the network is concerned, anyway) as per 4.1.3.4 (MUST).
2762	*/
2763	drop_reason = SKB_DROP_REASON_UDP_CSUM;
2764	net_dbg_ratelimited("UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
2765	proto == IPPROTO_UDPLITE ? "Lite" : "",
2766	&saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
2767	ulen);
2768	__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
2769	drop:
2770	__UDP_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
2771	sk_skb_reason_drop(sk, skb, reason: drop_reason);
2772	return `0`;
2773	}
2774
2775	/ We can only early demux multicast if there is a single matching socket.*
2776	* If more than one socket found returns NULL
2777	*/
2778	static struct sock __udp4_lib_mcast_demux_lookup(struct* net *net,
2779	__be16 loc_port, __be32 loc_addr,
2780	__be16 rmt_port, __be32 rmt_addr,
2781	int dif, int sdif)
2782	{
2783	struct udp_table *udptable = net->ipv4.udp_table;
2784	unsigned short hnum = ntohs(loc_port);
2785	struct sock sk, result;
2786	struct udp_hslot *hslot;
2787	unsigned int slot;
2788
2789	slot = udp_hashfn(net, num: hnum, mask: udptable->mask);
2790	hslot = &udptable->hash[slot];
2791
2792	/ Do not bother scanning a too big list /
2793	if (hslot->count > `10`)
2794	return NULL;
2795
2796	result = NULL;
2797	sk_for_each_rcu(sk, &hslot->head) {
2798	if (__udp_is_mcast_sock(net, sk, loc_port, loc_addr,
2799	rmt_port, rmt_addr, dif, sdif, hnum)) {
2800	if (result)
2801	return NULL;
2802	result = sk;
2803	}
2804	}
2805
2806	return result;
2807	}
2808
2809	/ For unicast we should only early demux connected sockets or we can*
2810	* break forwarding setups. The chains here can be long so only check
2811	* if the first socket is an exact match and if not move on.
2812	*/
2813	static struct sock __udp4_lib_demux_lookup(struct* net *net,
2814	__be16 loc_port, __be32 loc_addr,
2815	__be16 rmt_port, __be32 rmt_addr,
2816	int dif, int sdif)
2817	{
2818	struct udp_table *udptable = net->ipv4.udp_table;
2819	INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr);
2820	unsigned short hnum = ntohs(loc_port);
2821	struct udp_hslot *hslot2;
2822	unsigned int hash2;
2823	__portpair ports;
2824	struct sock *sk;
2825
2826	hash2 = ipv4_portaddr_hash(net, saddr: loc_addr, port: hnum);
2827	hslot2 = udp_hashslot2(table: udptable, hash: hash2);
2828	ports = INET_COMBINED_PORTS(rmt_port, hnum);
2829
2830	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
2831	if (inet_match(net, sk, cookie: acookie, ports, dif, sdif))
2832	return sk;
2833	/ Only check first socket in chain /
2834	break;
2835	}
2836	return NULL;
2837	}
2838
2839	enum skb_drop_reason udp_v4_early_demux(struct sk_buff *skb)
2840	{
2841	struct net *net = dev_net(dev: skb->dev);
2842	struct in_device *in_dev = NULL;
2843	const struct iphdr *iph;
2844	const struct udphdr *uh;
2845	struct sock *sk = NULL;
2846	struct dst_entry *dst;
2847	int dif = skb->dev->ifindex;
2848	int sdif = inet_sdif(skb);
2849	int ours;
2850
2851	/ validate the packet /
2852	if (!pskb_may_pull(skb, len: skb_transport_offset(skb) + sizeof(struct udphdr)))
2853	return SKB_NOT_DROPPED_YET;
2854
2855	iph = ip_hdr(skb);
2856	uh = udp_hdr(skb);
2857
2858	if (skb->pkt_type == PACKET_MULTICAST) {
2859	in_dev = __in_dev_get_rcu(dev: skb->dev);
2860
2861	if (!in_dev)
2862	return SKB_NOT_DROPPED_YET;
2863
2864	ours = ip_check_mc_rcu(dev: in_dev, mc_addr: iph->daddr, src_addr: iph->saddr,
2865	proto: iph->protocol);
2866	if (!ours)
2867	return SKB_NOT_DROPPED_YET;
2868
2869	sk = __udp4_lib_mcast_demux_lookup(net, loc_port: uh->dest, loc_addr: iph->daddr,
2870	rmt_port: uh->source, rmt_addr: iph->saddr,
2871	dif, sdif);
2872	} else if (skb->pkt_type == PACKET_HOST) {
2873	sk = __udp4_lib_demux_lookup(net, loc_port: uh->dest, loc_addr: iph->daddr,
2874	rmt_port: uh->source, rmt_addr: iph->saddr, dif, sdif);
2875	}
2876
2877	if (!sk)
2878	return SKB_NOT_DROPPED_YET;
2879
2880	skb->sk = sk;
2881	DEBUG_NET_WARN_ON_ONCE(sk_is_refcounted(sk));
2882	skb->destructor = sock_pfree;
2883	dst = rcu_dereference(sk->sk_rx_dst);
2884
2885	if (dst)
2886	dst = dst_check(dst, cookie: `0`);
2887	if (dst) {
2888	u32 itag = `0`;
2889
2890	/ set noref for now.*
2891	* any place which wants to hold dst has to call
2892	* dst_hold_safe()
2893	*/
2894	skb_dst_set_noref(skb, dst);
2895
2896	/ for unconnected multicast sockets we need to validate*
2897	* the source on each packet
2898	*/
2899	if (!inet_sk(sk)->inet_daddr && in_dev)
2900	return ip_mc_validate_source(skb, daddr: iph->daddr,
2901	saddr: iph->saddr,
2902	dscp: ip4h_dscp(ip4h: iph),
2903	dev: skb->dev, in_dev, itag: &itag);
2904	}
2905	return SKB_NOT_DROPPED_YET;
2906	}
2907
2908	int udp_rcv(struct sk_buff *skb)
2909	{
2910	return __udp4_lib_rcv(skb, udptable: dev_net(dev: skb->dev)->ipv4.udp_table, IPPROTO_UDP);
2911	}
2912
2913	void udp_destroy_sock(struct sock *sk)
2914	{
2915	struct udp_sock *up = udp_sk(sk);
2916	bool slow = lock_sock_fast(sk);
2917
2918	/ protects from races with udp_abort() /
2919	sock_set_flag(sk, flag: SOCK_DEAD);
2920	udp_flush_pending_frames(sk);
2921	unlock_sock_fast(sk, slow);
2922	if (static_branch_unlikely(&udp_encap_needed_key)) {
2923	if (up->encap_type) {
2924	void (encap_destroy)(struct* sock *sk);
2925	encap_destroy = READ_ONCE(up->encap_destroy);
2926	if (encap_destroy)
2927	encap_destroy(sk);
2928	}
2929	if (udp_test_bit(ENCAP_ENABLED, sk)) {
2930	static_branch_dec(&udp_encap_needed_key);
2931	udp_tunnel_cleanup_gro(sk);
2932	}
2933	}
2934	}
2935
2936	typedef struct sk_buff (udp_gro_receive_t)(struct sock *sk,
2937	struct list_head *head,
2938	struct sk_buff *skb);
2939
2940	static void set_xfrm_gro_udp_encap_rcv(__u16 encap_type, unsigned short family,
2941	struct sock *sk)
2942	{
2943	#ifdef CONFIG_XFRM
2944	udp_gro_receive_t new_gro_receive;
2945
2946	if (udp_test_bit(GRO_ENABLED, sk) && encap_type == UDP_ENCAP_ESPINUDP) {
2947	if (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6)
2948	new_gro_receive = ipv6_stub->xfrm6_gro_udp_encap_rcv;
2949	else
2950	new_gro_receive = xfrm4_gro_udp_encap_rcv;
2951
2952	if (udp_sk(sk)->gro_receive != new_gro_receive) {
2953	/*
2954	* With IPV6_ADDRFORM the gro callback could change
2955	* after being set, unregister the old one, if valid.
2956	*/
2957	if (udp_sk(sk)->gro_receive)
2958	udp_tunnel_update_gro_rcv(sk, add: false);
2959
2960	WRITE_ONCE(udp_sk(sk)->gro_receive, new_gro_receive);
2961	udp_tunnel_update_gro_rcv(sk, add: true);
2962	}
2963	}
2964	#endif
2965	}
2966
2967	/*
2968	* Socket option code for UDP
2969	*/
2970	int udp_lib_setsockopt(struct sock sk, int* level, int optname,
2971	sockptr_t optval, unsigned int optlen,
2972	int (push_pending_frames)(struct* sock *))
2973	{
2974	struct udp_sock *up = udp_sk(sk);
2975	int val, valbool;
2976	int err = `0`;
2977	int is_udplite = IS_UDPLITE(sk);
2978
2979	if (level == SOL_SOCKET) {
2980	err = sk_setsockopt(sk, level, optname, optval, optlen);
2981
2982	if (optname == SO_RCVBUF \|\| optname == SO_RCVBUFFORCE) {
2983	sockopt_lock_sock(sk);
2984	/ paired with READ_ONCE in udp_rmem_release() /
2985	WRITE_ONCE(up->forward_threshold, sk->sk_rcvbuf >> `2`);
2986	sockopt_release_sock(sk);
2987	}
2988	return err;
2989	}
2990
2991	if (optlen < sizeof(int))
2992	return -EINVAL;
2993
2994	if (copy_from_sockptr(dst: &val, src: optval, size: sizeof(val)))
2995	return -EFAULT;
2996
2997	valbool = val ? `1` : `0`;
2998
2999	switch (optname) {
3000	case UDP_CORK:
3001	if (val != `0`) {
3002	udp_set_bit(CORK, sk);
3003	} else {
3004	udp_clear_bit(CORK, sk);
3005	lock_sock(sk);
3006	push_pending_frames(sk);
3007	release_sock(sk);
3008	}
3009	break;
3010
3011	case UDP_ENCAP:
3012	sockopt_lock_sock(sk);
3013	switch (val) {
3014	case `0`:
3015	#ifdef CONFIG_XFRM
3016	case UDP_ENCAP_ESPINUDP:
3017	set_xfrm_gro_udp_encap_rcv(encap_type: val, family: sk->sk_family, sk);
3018	#if IS_ENABLED(CONFIG_IPV6)
3019	if (sk->sk_family == AF_INET6)
3020	WRITE_ONCE(up->encap_rcv,
3021	ipv6_stub->xfrm6_udp_encap_rcv);
3022	else
3023	#endif
3024	WRITE_ONCE(up->encap_rcv,
3025	xfrm4_udp_encap_rcv);
3026	#endif
3027	fallthrough;
3028	case UDP_ENCAP_L2TPINUDP:
3029	WRITE_ONCE(up->encap_type, val);
3030	udp_tunnel_encap_enable(sk);
3031	break;
3032	default:
3033	err = -ENOPROTOOPT;
3034	break;
3035	}
3036	sockopt_release_sock(sk);
3037	break;
3038
3039	case UDP_NO_CHECK6_TX:
3040	udp_set_no_check6_tx(sk, val: valbool);
3041	break;
3042
3043	case UDP_NO_CHECK6_RX:
3044	udp_set_no_check6_rx(sk, val: valbool);
3045	break;
3046
3047	case UDP_SEGMENT:
3048	if (val < `0` \|\| val > USHRT_MAX)
3049	return -EINVAL;
3050	WRITE_ONCE(up->gso_size, val);
3051	break;
3052
3053	case UDP_GRO:
3054	sockopt_lock_sock(sk);
3055	/ when enabling GRO, accept the related GSO packet type /
3056	if (valbool)
3057	udp_tunnel_encap_enable(sk);
3058	udp_assign_bit(GRO_ENABLED, sk, valbool);
3059	udp_assign_bit(ACCEPT_L4, sk, valbool);
3060	set_xfrm_gro_udp_encap_rcv(encap_type: up->encap_type, family: sk->sk_family, sk);
3061	sockopt_release_sock(sk);
3062	break;
3063
3064	/*
3065	* UDP-Lite's partial checksum coverage (RFC 3828).
3066	*/
3067	/ The sender sets actual checksum coverage length via this option.*
3068	* The case coverage > packet length is handled by send module. */
3069	case UDPLITE_SEND_CSCOV:
3070	if (!is_udplite) / Disable the option on UDP sockets /
3071	return -ENOPROTOOPT;
3072	if (val != `0` && val < `8`) / Illegal coverage: use default (8) /
3073	val = `8`;
3074	else if (val > USHRT_MAX)
3075	val = USHRT_MAX;
3076	WRITE_ONCE(up->pcslen, val);
3077	udp_set_bit(UDPLITE_SEND_CC, sk);
3078	break;
3079
3080	/ The receiver specifies a minimum checksum coverage value. To make*
3081	* sense, this should be set to at least 8 (as done below). If zero is
3082	* used, this again means full checksum coverage. */
3083	case UDPLITE_RECV_CSCOV:
3084	if (!is_udplite) / Disable the option on UDP sockets /
3085	return -ENOPROTOOPT;
3086	if (val != `0` && val < `8`) / Avoid silly minimal values. /
3087	val = `8`;
3088	else if (val > USHRT_MAX)
3089	val = USHRT_MAX;
3090	WRITE_ONCE(up->pcrlen, val);
3091	udp_set_bit(UDPLITE_RECV_CC, sk);
3092	break;
3093
3094	default:
3095	err = -ENOPROTOOPT;
3096	break;
3097	}
3098
3099	return err;
3100	}
3101	EXPORT_IPV6_MOD(udp_lib_setsockopt);
3102
3103	int udp_setsockopt(struct sock sk, int* level, int optname, sockptr_t optval,
3104	unsigned int optlen)
3105	{
3106	if (level == SOL_UDP \|\| level == SOL_UDPLITE \|\| level == SOL_SOCKET)
3107	return udp_lib_setsockopt(sk, level, optname,
3108	optval, optlen,
3109	push_pending_frames: udp_push_pending_frames);
3110	return ip_setsockopt(sk, level, optname, optval, optlen);
3111	}
3112
3113	int udp_lib_getsockopt(struct sock sk, int* level, int optname,
3114	char __user optval, int* __user *optlen)
3115	{
3116	struct udp_sock *up = udp_sk(sk);
3117	int val, len;
3118
3119	if (get_user(len, optlen))
3120	return -EFAULT;
3121
3122	if (len < `0`)
3123	return -EINVAL;
3124
3125	len = min_t(unsigned int, len, sizeof(int));
3126
3127	switch (optname) {
3128	case UDP_CORK:
3129	val = udp_test_bit(CORK, sk);
3130	break;
3131
3132	case UDP_ENCAP:
3133	val = READ_ONCE(up->encap_type);
3134	break;
3135
3136	case UDP_NO_CHECK6_TX:
3137	val = udp_get_no_check6_tx(sk);
3138	break;
3139
3140	case UDP_NO_CHECK6_RX:
3141	val = udp_get_no_check6_rx(sk);
3142	break;
3143
3144	case UDP_SEGMENT:
3145	val = READ_ONCE(up->gso_size);
3146	break;
3147
3148	case UDP_GRO:
3149	val = udp_test_bit(GRO_ENABLED, sk);
3150	break;
3151
3152	/ The following two cannot be changed on UDP sockets, the return is*
3153	* always 0 (which corresponds to the full checksum coverage of UDP). */
3154	case UDPLITE_SEND_CSCOV:
3155	val = READ_ONCE(up->pcslen);
3156	break;
3157
3158	case UDPLITE_RECV_CSCOV:
3159	val = READ_ONCE(up->pcrlen);
3160	break;
3161
3162	default:
3163	return -ENOPROTOOPT;
3164	}
3165
3166	if (put_user(len, optlen))
3167	return -EFAULT;
3168	if (copy_to_user(to: optval, from: &val, n: len))
3169	return -EFAULT;
3170	return `0`;
3171	}
3172	EXPORT_IPV6_MOD(udp_lib_getsockopt);
3173
3174	int udp_getsockopt(struct sock sk, int* level, int optname,
3175	char __user optval, int* __user *optlen)
3176	{
3177	if (level == SOL_UDP \|\| level == SOL_UDPLITE)
3178	return udp_lib_getsockopt(sk, level, optname, optval, optlen);
3179	return ip_getsockopt(sk, level, optname, optval, optlen);
3180	}
3181
3182	/**
3183	* udp_poll - wait for a UDP event.
3184	* @file: - file struct
3185	* @sock: - socket
3186	* @wait: - poll table
3187	*
3188	* This is same as datagram poll, except for the special case of
3189	* blocking sockets. If application is using a blocking fd
3190	* and a packet with checksum error is in the queue;
3191	* then it could get return from select indicating data available
3192	* but then block when reading it. Add special case code
3193	* to work around these arguably broken applications.
3194	*/
3195	__poll_t udp_poll(struct file file, struct* socket sock, poll_table wait)
3196	{
3197	__poll_t mask = datagram_poll(file, sock, wait);
3198	struct sock *sk = sock->sk;
3199
3200	if (!skb_queue_empty_lockless(list: &udp_sk(sk)->reader_queue))
3201	mask \|= EPOLLIN \| EPOLLRDNORM;
3202
3203	/ Check for false positives due to checksum errors /
3204	if ((mask & EPOLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
3205	!(sk->sk_shutdown & RCV_SHUTDOWN) && first_packet_length(sk) == -`1`)
3206	mask &= ~(EPOLLIN \| EPOLLRDNORM);
3207
3208	/ psock ingress_msg queue should not contain any bad checksum frames /
3209	if (sk_is_readable(sk))
3210	mask \|= EPOLLIN \| EPOLLRDNORM;
3211	return mask;
3212
3213	}
3214	EXPORT_IPV6_MOD(udp_poll);
3215
3216	int udp_abort(struct sock sk, int* err)
3217	{
3218	if (!has_current_bpf_ctx())
3219	lock_sock(sk);
3220
3221	/ udp{v6}_destroy_sock() sets it under the sk lock, avoid racing*
3222	* with close()
3223	*/
3224	if (sock_flag(sk, flag: SOCK_DEAD))
3225	goto out;
3226
3227	sk->sk_err = err;
3228	sk_error_report(sk);
3229	__udp_disconnect(sk, `0`);
3230
3231	out:
3232	if (!has_current_bpf_ctx())
3233	release_sock(sk);
3234
3235	return `0`;
3236	}
3237	EXPORT_IPV6_MOD_GPL(udp_abort);
3238
3239	struct proto udp_prot = {
3240	.name = "UDP",
3241	.owner = THIS_MODULE,
3242	.close = udp_lib_close,
3243	.pre_connect = udp_pre_connect,
3244	.connect = udp_connect,
3245	.disconnect = udp_disconnect,
3246	.ioctl = udp_ioctl,
3247	.init = udp_init_sock,
3248	.destroy = udp_destroy_sock,
3249	.setsockopt = udp_setsockopt,
3250	.getsockopt = udp_getsockopt,
3251	.sendmsg = udp_sendmsg,
3252	.recvmsg = udp_recvmsg,
3253	.splice_eof = udp_splice_eof,
3254	.release_cb = ip4_datagram_release_cb,
3255	.hash = udp_lib_hash,
3256	.unhash = udp_lib_unhash,
3257	.rehash = udp_v4_rehash,
3258	.get_port = udp_v4_get_port,
3259	.put_port = udp_lib_unhash,
3260	#ifdef CONFIG_BPF_SYSCALL
3261	.psock_update_sk_prot = udp_bpf_update_proto,
3262	#endif
3263	.memory_allocated = &net_aligned_data.udp_memory_allocated,
3264	.per_cpu_fw_alloc = &udp_memory_per_cpu_fw_alloc,
3265
3266	.sysctl_mem = sysctl_udp_mem,
3267	.sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_udp_wmem_min),
3268	.sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_udp_rmem_min),
3269	.obj_size = sizeof(struct udp_sock),
3270	.h.udp_table = NULL,
3271	.diag_destroy = udp_abort,
3272	};
3273	EXPORT_SYMBOL(udp_prot);
3274
3275	/ ------------------------------------------------------------------------ /
3276	#ifdef CONFIG_PROC_FS
3277
3278	static unsigned short seq_file_family(const struct seq_file *seq);
3279	static bool seq_sk_match(struct seq_file seq, const* struct sock *sk)
3280	{
3281	unsigned short family = seq_file_family(seq);
3282
3283	/ AF_UNSPEC is used as a match all /
3284	return ((family == AF_UNSPEC \|\| family == sk->sk_family) &&
3285	net_eq(net1: sock_net(sk), net2: seq_file_net(seq)));
3286	}
3287
3288	#ifdef CONFIG_BPF_SYSCALL
3289	static const struct seq_operations bpf_iter_udp_seq_ops;
3290	#endif
3291	static struct udp_table udp_get_table_seq(struct* seq_file *seq,
3292	struct net *net)
3293	{
3294	const struct udp_seq_afinfo *afinfo;
3295
3296	#ifdef CONFIG_BPF_SYSCALL
3297	if (seq->op == &bpf_iter_udp_seq_ops)
3298	return net->ipv4.udp_table;
3299	#endif
3300
3301	afinfo = pde_data(inode: file_inode(f: seq->file));
3302	return afinfo->udp_table ? : net->ipv4.udp_table;
3303	}
3304
3305	static struct sock udp_get_first(struct* seq_file seq, int* start)
3306	{
3307	struct udp_iter_state *state = seq->private;
3308	struct net *net = seq_file_net(seq);
3309	struct udp_table *udptable;
3310	struct sock *sk;
3311
3312	udptable = udp_get_table_seq(seq, net);
3313
3314	for (state->bucket = start; state->bucket <= udptable->mask;
3315	++state->bucket) {
3316	struct udp_hslot *hslot = &udptable->hash[state->bucket];
3317
3318	if (hlist_empty(h: &hslot->head))
3319	continue;
3320
3321	spin_lock_bh(lock: &hslot->lock);
3322	sk_for_each(sk, &hslot->head) {
3323	if (seq_sk_match(seq, sk))
3324	goto found;
3325	}
3326	spin_unlock_bh(lock: &hslot->lock);
3327	}
3328	sk = NULL;
3329	found:
3330	return sk;
3331	}
3332
3333	static struct sock udp_get_next(struct* seq_file seq, struct* sock *sk)
3334	{
3335	struct udp_iter_state *state = seq->private;
3336	struct net *net = seq_file_net(seq);
3337	struct udp_table *udptable;
3338
3339	do {
3340	sk = sk_next(sk);
3341	} while (sk && !seq_sk_match(seq, sk));
3342
3343	if (!sk) {
3344	udptable = udp_get_table_seq(seq, net);
3345
3346	if (state->bucket <= udptable->mask)
3347	spin_unlock_bh(lock: &udptable->hash[state->bucket].lock);
3348
3349	return udp_get_first(seq, start: state->bucket + `1`);
3350	}
3351	return sk;
3352	}
3353
3354	static struct sock udp_get_idx(struct* seq_file *seq, loff_t pos)
3355	{
3356	struct sock *sk = udp_get_first(seq, start: `0`);
3357
3358	if (sk)
3359	while (pos && (sk = udp_get_next(seq, sk)) != NULL)
3360	--pos;
3361	return pos ? NULL : sk;
3362	}
3363
3364	void udp_seq_start(struct* seq_file seq, loff_t pos)
3365	{
3366	struct udp_iter_state *state = seq->private;
3367	state->bucket = MAX_UDP_PORTS;
3368
3369	return pos ? udp_get_idx(seq, pos: pos-`1`) : SEQ_START_TOKEN;
3370	}
3371	EXPORT_IPV6_MOD(udp_seq_start);
3372
3373	void udp_seq_next(struct* seq_file seq, void* v, loff_t pos)
3374	{
3375	struct sock *sk;
3376
3377	if (v == SEQ_START_TOKEN)
3378	sk = udp_get_idx(seq, pos: `0`);
3379	else
3380	sk = udp_get_next(seq, sk: v);
3381
3382	++*pos;
3383	return sk;
3384	}
3385	EXPORT_IPV6_MOD(udp_seq_next);
3386
3387	void udp_seq_stop(struct seq_file seq, void* *v)
3388	{
3389	struct udp_iter_state *state = seq->private;
3390	struct udp_table *udptable;
3391
3392	udptable = udp_get_table_seq(seq, net: seq_file_net(seq));
3393
3394	if (state->bucket <= udptable->mask)
3395	spin_unlock_bh(lock: &udptable->hash[state->bucket].lock);
3396	}
3397	EXPORT_IPV6_MOD(udp_seq_stop);
3398
3399	/ ------------------------------------------------------------------------ /
3400	static void udp4_format_sock(struct sock sp, struct* seq_file *f,
3401	int bucket)
3402	{
3403	struct inet_sock *inet = inet_sk(sp);
3404	__be32 dest = inet->inet_daddr;
3405	__be32 src = inet->inet_rcv_saddr;
3406	__u16 destp = ntohs(inet->inet_dport);
3407	__u16 srcp = ntohs(inet->inet_sport);
3408
3409	seq_printf(m: f, fmt: "%5d: %08X:%04X %08X:%04X"
3410	" %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u",
3411	bucket, src, srcp, dest, destp, sp->sk_state,
3412	sk_wmem_alloc_get(sk: sp),
3413	udp_rqueue_get(sk: sp),
3414	`0`, `0L`, `0`,
3415	from_kuid_munged(to: seq_user_ns(seq: f), kuid: sk_uid(sk: sp)),
3416	`0`, sock_i_ino(sk: sp),
3417	refcount_read(r: &sp->sk_refcnt), sp,
3418	sk_drops_read(sk: sp));
3419	}
3420
3421	int udp4_seq_show(struct seq_file seq, void* *v)
3422	{
3423	seq_setwidth(m: seq, size: `127`);
3424	if (v == SEQ_START_TOKEN)
3425	seq_puts(m: seq, s: " sl local_address rem_address st tx_queue "
3426	"rx_queue tr tm->when retrnsmt uid timeout "
3427	"inode ref pointer drops");
3428	else {
3429	struct udp_iter_state *state = seq->private;
3430
3431	udp4_format_sock(sp: v, f: seq, bucket: state->bucket);
3432	}
3433	seq_pad(m: seq, c: `'\n'`);
3434	return `0`;
3435	}
3436
3437	#ifdef CONFIG_BPF_SYSCALL
3438	struct bpf_iter__udp {
3439	__bpf_md_ptr(struct bpf_iter_meta *, meta);
3440	__bpf_md_ptr(struct udp_sock *, udp_sk);
3441	uid_t uid __aligned(`8`);
3442	int bucket __aligned(`8`);
3443	};
3444
3445	union bpf_udp_iter_batch_item {
3446	struct sock *sk;
3447	__u64 cookie;
3448	};
3449
3450	struct bpf_udp_iter_state {
3451	struct udp_iter_state state;
3452	unsigned int cur_sk;
3453	unsigned int end_sk;
3454	unsigned int max_sk;
3455	union bpf_udp_iter_batch_item *batch;
3456	};
3457
3458	static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter,
3459	unsigned int new_batch_sz, gfp_t flags);
3460	static struct sock bpf_iter_udp_resume(struct* sock *first_sk,
3461	union bpf_udp_iter_batch_item *cookies,
3462	int n_cookies)
3463	{
3464	struct sock *sk = NULL;
3465	int i;
3466
3467	for (i = `0`; i < n_cookies; i++) {
3468	sk = first_sk;
3469	udp_portaddr_for_each_entry_from(sk)
3470	if (cookies[i].cookie == atomic64_read(&sk->sk_cookie))
3471	goto done;
3472	}
3473	done:
3474	return sk;
3475	}
3476
3477	static struct sock bpf_iter_udp_batch(struct* seq_file *seq)
3478	{
3479	struct bpf_udp_iter_state *iter = seq->private;
3480	struct udp_iter_state *state = &iter->state;
3481	unsigned int find_cookie, end_cookie;
3482	struct net *net = seq_file_net(seq);
3483	struct udp_table *udptable;
3484	unsigned int batch_sks = `0`;
3485	int resume_bucket;
3486	int resizes = `0`;
3487	struct sock *sk;
3488	int err = `0`;
3489
3490	resume_bucket = state->bucket;
3491
3492	/ The current batch is done, so advance the bucket. /
3493	if (iter->cur_sk == iter->end_sk)
3494	state->bucket++;
3495
3496	udptable = udp_get_table_seq(seq, net);
3497
3498	again:
3499	/ New batch for the next bucket.*
3500	* Iterate over the hash table to find a bucket with sockets matching
3501	* the iterator attributes, and return the first matching socket from
3502	* the bucket. The remaining matched sockets from the bucket are batched
3503	* before releasing the bucket lock. This allows BPF programs that are
3504	* called in seq_show to acquire the bucket lock if needed.
3505	*/
3506	find_cookie = iter->cur_sk;
3507	end_cookie = iter->end_sk;
3508	iter->cur_sk = `0`;
3509	iter->end_sk = `0`;
3510	batch_sks = `0`;
3511
3512	for (; state->bucket <= udptable->mask; state->bucket++) {
3513	struct udp_hslot *hslot2 = &udptable->hash2[state->bucket].hslot;
3514
3515	if (hlist_empty(&hslot2->head))
3516	goto next_bucket;
3517
3518	spin_lock_bh(&hslot2->lock);
3519	sk = hlist_entry_safe(hslot2->head.first, struct sock,
3520	__sk_common.skc_portaddr_node);
3521	/ Resume from the first (in iteration order) unseen socket from*
3522	* the last batch that still exists in resume_bucket. Most of
3523	* the time this will just be where the last iteration left off
3524	* in resume_bucket unless that socket disappeared between
3525	* reads.
3526	*/
3527	if (state->bucket == resume_bucket)
3528	sk = bpf_iter_udp_resume(sk, &iter->batch[find_cookie],
3529	end_cookie - find_cookie);
3530	fill_batch:
3531	udp_portaddr_for_each_entry_from(sk) {
3532	if (seq_sk_match(seq, sk)) {
3533	if (iter->end_sk < iter->max_sk) {
3534	sock_hold(sk);
3535	iter->batch[iter->end_sk++].sk = sk;
3536	}
3537	batch_sks++;
3538	}
3539	}
3540
3541	/ Allocate a larger batch and try again. /
3542	if (unlikely(resizes <= `1` && iter->end_sk &&
3543	iter->end_sk != batch_sks)) {
3544	resizes++;
3545
3546	/ First, try with GFP_USER to maximize the chances of*
3547	* grabbing more memory.
3548	*/
3549	if (resizes == `1`) {
3550	spin_unlock_bh(&hslot2->lock);
3551	err = bpf_iter_udp_realloc_batch(iter,
3552	batch_sks * `3` / `2`,
3553	GFP_USER);
3554	if (err)
3555	return ERR_PTR(err);
3556	/ Start over. /
3557	goto again;
3558	}
3559
3560	/ Next, hold onto the lock, so the bucket doesn't*
3561	* change while we get the rest of the sockets.
3562	*/
3563	err = bpf_iter_udp_realloc_batch(iter, batch_sks,
3564	GFP_NOWAIT);
3565	if (err) {
3566	spin_unlock_bh(&hslot2->lock);
3567	return ERR_PTR(err);
3568	}
3569
3570	/ Pick up where we left off. /
3571	sk = iter->batch[iter->end_sk - `1`].sk;
3572	sk = hlist_entry_safe(sk->__sk_common.skc_portaddr_node.next,
3573	struct sock,
3574	__sk_common.skc_portaddr_node);
3575	batch_sks = iter->end_sk;
3576	goto fill_batch;
3577	}
3578
3579	spin_unlock_bh(&hslot2->lock);
3580
3581	if (iter->end_sk)
3582	break;
3583	next_bucket:
3584	resizes = `0`;
3585	}
3586
3587	WARN_ON_ONCE(iter->end_sk != batch_sks);
3588	return iter->end_sk ? iter->batch[`0`].sk : NULL;
3589	}
3590
3591	static void bpf_iter_udp_seq_next(struct* seq_file seq, void* v, loff_t pos)
3592	{
3593	struct bpf_udp_iter_state *iter = seq->private;
3594	struct sock *sk;
3595
3596	/ Whenever seq_next() is called, the iter->cur_sk is*
3597	* done with seq_show(), so unref the iter->cur_sk.
3598	*/
3599	if (iter->cur_sk < iter->end_sk)
3600	sock_put(iter->batch[iter->cur_sk++].sk);
3601
3602	/ After updating iter->cur_sk, check if there are more sockets*
3603	* available in the current bucket batch.
3604	*/
3605	if (iter->cur_sk < iter->end_sk)
3606	sk = iter->batch[iter->cur_sk].sk;
3607	else
3608	/ Prepare a new batch. /
3609	sk = bpf_iter_udp_batch(seq);
3610
3611	++*pos;
3612	return sk;
3613	}
3614
3615	static void bpf_iter_udp_seq_start(struct* seq_file seq, loff_t pos)
3616	{
3617	/ bpf iter does not support lseek, so it always*
3618	* continue from where it was stop()-ped.
3619	*/
3620	if (*pos)
3621	return bpf_iter_udp_batch(seq);
3622
3623	return SEQ_START_TOKEN;
3624	}
3625
3626	static int udp_prog_seq_show(struct bpf_prog prog, struct* bpf_iter_meta *meta,
3627	struct udp_sock udp_sk, uid_t uid, int* bucket)
3628	{
3629	struct bpf_iter__udp ctx;
3630
3631	meta->seq_num--; / skip SEQ_START_TOKEN /
3632	ctx.meta = meta;
3633	ctx.udp_sk = udp_sk;
3634	ctx.uid = uid;
3635	ctx.bucket = bucket;
3636	return bpf_iter_run_prog(prog, &ctx);
3637	}
3638
3639	static int bpf_iter_udp_seq_show(struct seq_file seq, void* *v)
3640	{
3641	struct udp_iter_state *state = seq->private;
3642	struct bpf_iter_meta meta;
3643	struct bpf_prog *prog;
3644	struct sock *sk = v;
3645	uid_t uid;
3646	int ret;
3647
3648	if (v == SEQ_START_TOKEN)
3649	return `0`;
3650
3651	lock_sock(sk);
3652
3653	if (unlikely(sk_unhashed(sk))) {
3654	ret = SEQ_SKIP;
3655	goto unlock;
3656	}
3657
3658	uid = from_kuid_munged(seq_user_ns(seq), sk_uid(sk));
3659	meta.seq = seq;
3660	prog = bpf_iter_get_info(&meta, false);
3661	ret = udp_prog_seq_show(prog, &meta, v, uid, state->bucket);
3662
3663	unlock:
3664	release_sock(sk);
3665	return ret;
3666	}
3667
3668	static void bpf_iter_udp_put_batch(struct bpf_udp_iter_state *iter)
3669	{
3670	union bpf_udp_iter_batch_item *item;
3671	unsigned int cur_sk = iter->cur_sk;
3672	__u64 cookie;
3673
3674	/ Remember the cookies of the sockets we haven't seen yet, so we can*
3675	* pick up where we left off next time around.
3676	*/
3677	while (cur_sk < iter->end_sk) {
3678	item = &iter->batch[cur_sk++];
3679	cookie = sock_gen_cookie(item->sk);
3680	sock_put(item->sk);
3681	item->cookie = cookie;
3682	}
3683	}
3684
3685	static void bpf_iter_udp_seq_stop(struct seq_file seq, void* *v)
3686	{
3687	struct bpf_udp_iter_state *iter = seq->private;
3688	struct bpf_iter_meta meta;
3689	struct bpf_prog *prog;
3690
3691	if (!v) {
3692	meta.seq = seq;
3693	prog = bpf_iter_get_info(&meta, true);
3694	if (prog)
3695	(void)udp_prog_seq_show(prog, &meta, v, `0`, `0`);
3696	}
3697
3698	if (iter->cur_sk < iter->end_sk)
3699	bpf_iter_udp_put_batch(iter);
3700	}
3701
3702	static const struct seq_operations bpf_iter_udp_seq_ops = {
3703	.start = bpf_iter_udp_seq_start,
3704	.next = bpf_iter_udp_seq_next,
3705	.stop = bpf_iter_udp_seq_stop,
3706	.show = bpf_iter_udp_seq_show,
3707	};
3708	#endif
3709
3710	static unsigned short seq_file_family(const struct seq_file *seq)
3711	{
3712	const struct udp_seq_afinfo *afinfo;
3713
3714	#ifdef CONFIG_BPF_SYSCALL
3715	/ BPF iterator: bpf programs to filter sockets. /
3716	if (seq->op == &bpf_iter_udp_seq_ops)
3717	return AF_UNSPEC;
3718	#endif
3719
3720	/ Proc fs iterator /
3721	afinfo = pde_data(inode: file_inode(f: seq->file));
3722	return afinfo->family;
3723	}
3724
3725	const struct seq_operations udp_seq_ops = {
3726	.start = udp_seq_start,
3727	.next = udp_seq_next,
3728	.stop = udp_seq_stop,
3729	.show = udp4_seq_show,
3730	};
3731	EXPORT_IPV6_MOD(udp_seq_ops);
3732
3733	static struct udp_seq_afinfo udp4_seq_afinfo = {
3734	.family = AF_INET,
3735	.udp_table = NULL,
3736	};
3737
3738	static int __net_init udp4_proc_init_net(struct net *net)
3739	{
3740	if (!proc_create_net_data(name: "udp", mode: `0444`, parent: net->proc_net, ops: &udp_seq_ops,
3741	state_size: sizeof(struct udp_iter_state), data: &udp4_seq_afinfo))
3742	return -ENOMEM;
3743	return `0`;
3744	}
3745
3746	static void __net_exit udp4_proc_exit_net(struct net *net)
3747	{
3748	remove_proc_entry("udp", net->proc_net);
3749	}
3750
3751	static struct pernet_operations udp4_net_ops = {
3752	.init = udp4_proc_init_net,
3753	.exit = udp4_proc_exit_net,
3754	};
3755
3756	int __init udp4_proc_init(void)
3757	{
3758	return register_pernet_subsys(&udp4_net_ops);
3759	}
3760
3761	void udp4_proc_exit(void)
3762	{
3763	unregister_pernet_subsys(&udp4_net_ops);
3764	}
3765	#endif /* CONFIG_PROC_FS */
3766
3767	static __initdata unsigned long uhash_entries;
3768	static int __init set_uhash_entries(char *str)
3769	{
3770	ssize_t ret;
3771
3772	if (!str)
3773	return `0`;
3774
3775	ret = kstrtoul(s: str, base: `0`, res: &uhash_entries);
3776	if (ret)
3777	return `0`;
3778
3779	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
3780	uhash_entries = UDP_HTABLE_SIZE_MIN;
3781	return `1`;
3782	}
3783	__setup("uhash_entries=", set_uhash_entries);
3784
3785	void __init udp_table_init(struct udp_table table, const* char *name)
3786	{
3787	unsigned int i, slot_size;
3788
3789	slot_size = sizeof(struct udp_hslot) + sizeof(struct udp_hslot_main) +
3790	udp_hash4_slot_size();
3791	table->hash = alloc_large_system_hash(tablename: name,
3792	bucketsize: slot_size,
3793	numentries: uhash_entries,
3794	scale: `21`, / one slot per 2 MB /
3795	flags: `0`,
3796	hash_shift: &table->log,
3797	hash_mask: &table->mask,
3798	UDP_HTABLE_SIZE_MIN,
3799	UDP_HTABLE_SIZE_MAX);
3800
3801	table->hash2 = (void *)(table->hash + (table->mask + `1`));
3802	for (i = `0`; i <= table->mask; i++) {
3803	INIT_HLIST_HEAD(&table->hash[i].head);
3804	table->hash[i].count = `0`;
3805	spin_lock_init(&table->hash[i].lock);
3806	}
3807	for (i = `0`; i <= table->mask; i++) {
3808	INIT_HLIST_HEAD(&table->hash2[i].hslot.head);
3809	table->hash2[i].hslot.count = `0`;
3810	spin_lock_init(&table->hash2[i].hslot.lock);
3811	}
3812	udp_table_hash4_init(table);
3813	}
3814
3815	u32 udp_flow_hashrnd(void)
3816	{
3817	static u32 hashrnd __read_mostly;
3818
3819	net_get_random_once(&hashrnd, sizeof(hashrnd));
3820
3821	return hashrnd;
3822	}
3823	EXPORT_SYMBOL(udp_flow_hashrnd);
3824
3825	static void __net_init udp_sysctl_init(struct net *net)
3826	{
3827	net->ipv4.sysctl_udp_rmem_min = PAGE_SIZE;
3828	net->ipv4.sysctl_udp_wmem_min = PAGE_SIZE;
3829
3830	#ifdef CONFIG_NET_L3_MASTER_DEV
3831	net->ipv4.sysctl_udp_l3mdev_accept = `0`;
3832	#endif
3833	}
3834
3835	static struct udp_table __net_init udp_pernet_table_alloc(unsigned* int hash_entries)
3836	{
3837	struct udp_table *udptable;
3838	unsigned int slot_size;
3839	int i;
3840
3841	udptable = kmalloc(sizeof(*udptable), GFP_KERNEL);
3842	if (!udptable)
3843	goto out;
3844
3845	slot_size = sizeof(struct udp_hslot) + sizeof(struct udp_hslot_main) +
3846	udp_hash4_slot_size();
3847	udptable->hash = vmalloc_huge(size: hash_entries * slot_size,
3848	GFP_KERNEL_ACCOUNT);
3849	if (!udptable->hash)
3850	goto free_table;
3851
3852	udptable->hash2 = (void *)(udptable->hash + hash_entries);
3853	udptable->mask = hash_entries - `1`;
3854	udptable->log = ilog2(hash_entries);
3855
3856	for (i = `0`; i < hash_entries; i++) {
3857	INIT_HLIST_HEAD(&udptable->hash[i].head);
3858	udptable->hash[i].count = `0`;
3859	spin_lock_init(&udptable->hash[i].lock);
3860
3861	INIT_HLIST_HEAD(&udptable->hash2[i].hslot.head);
3862	udptable->hash2[i].hslot.count = `0`;
3863	spin_lock_init(&udptable->hash2[i].hslot.lock);
3864	}
3865	udp_table_hash4_init(table: udptable);
3866
3867	return udptable;
3868
3869	free_table:
3870	kfree(objp: udptable);
3871	out:
3872	return NULL;
3873	}
3874
3875	static void __net_exit udp_pernet_table_free(struct net *net)
3876	{
3877	struct udp_table *udptable = net->ipv4.udp_table;
3878
3879	if (udptable == &udp_table)
3880	return;
3881
3882	kvfree(addr: udptable->hash);
3883	kfree(objp: udptable);
3884	}
3885
3886	static void __net_init udp_set_table(struct net *net)
3887	{
3888	struct udp_table *udptable;
3889	unsigned int hash_entries;
3890	struct net *old_net;
3891
3892	if (net_eq(net1: net, net2: &init_net))
3893	goto fallback;
3894
3895	old_net = current->nsproxy->net_ns;
3896	hash_entries = READ_ONCE(old_net->ipv4.sysctl_udp_child_hash_entries);
3897	if (!hash_entries)
3898	goto fallback;
3899
3900	/ Set min to keep the bitmap on stack in udp_lib_get_port() /
3901	if (hash_entries < UDP_HTABLE_SIZE_MIN_PERNET)
3902	hash_entries = UDP_HTABLE_SIZE_MIN_PERNET;
3903	else
3904	hash_entries = roundup_pow_of_two(hash_entries);
3905
3906	udptable = udp_pernet_table_alloc(hash_entries);
3907	if (udptable) {
3908	net->ipv4.udp_table = udptable;
3909	} else {
3910	pr_warn("Failed to allocate UDP hash table (entries: %u) "
3911	"for a netns, fallback to the global one\n",
3912	hash_entries);
3913	fallback:
3914	net->ipv4.udp_table = &udp_table;
3915	}
3916	}
3917
3918	static int __net_init udp_pernet_init(struct net *net)
3919	{
3920	#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL)
3921	int i;
3922
3923	/ No tunnel is configured /
3924	for (i = `0`; i < ARRAY_SIZE(net->ipv4.udp_tunnel_gro); ++i) {
3925	INIT_HLIST_HEAD(&net->ipv4.udp_tunnel_gro[i].list);
3926	RCU_INIT_POINTER(net->ipv4.udp_tunnel_gro[i].sk, NULL);
3927	}
3928	#endif
3929	udp_sysctl_init(net);
3930	udp_set_table(net);
3931
3932	return `0`;
3933	}
3934
3935	static void __net_exit udp_pernet_exit(struct net *net)
3936	{
3937	udp_pernet_table_free(net);
3938	}
3939
3940	static struct pernet_operations __net_initdata udp_sysctl_ops = {
3941	.init = udp_pernet_init,
3942	.exit = udp_pernet_exit,
3943	};
3944
3945	#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
3946	DEFINE_BPF_ITER_FUNC(udp, struct bpf_iter_meta *meta,
3947	struct udp_sock udp_sk, uid_t uid, int* bucket)
3948
3949	static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter,
3950	unsigned int new_batch_sz, gfp_t flags)
3951	{
3952	union bpf_udp_iter_batch_item *new_batch;
3953
3954	new_batch = kvmalloc_array(new_batch_sz, sizeof(*new_batch),
3955	flags \| __GFP_NOWARN);
3956	if (!new_batch)
3957	return -ENOMEM;
3958
3959	if (flags != GFP_NOWAIT)
3960	bpf_iter_udp_put_batch(iter);
3961
3962	memcpy(new_batch, iter->batch, sizeof(iter->batch) iter->end_sk);
3963	kvfree(iter->batch);
3964	iter->batch = new_batch;
3965	iter->max_sk = new_batch_sz;
3966
3967	return `0`;
3968	}
3969
3970	#define INIT_BATCH_SZ 16
3971
3972	static int bpf_iter_init_udp(void priv_data, struct* bpf_iter_aux_info *aux)
3973	{
3974	struct bpf_udp_iter_state *iter = priv_data;
3975	int ret;
3976
3977	ret = bpf_iter_init_seq_net(priv_data, aux);
3978	if (ret)
3979	return ret;
3980
3981	ret = bpf_iter_udp_realloc_batch(iter, INIT_BATCH_SZ, GFP_USER);
3982	if (ret)
3983	bpf_iter_fini_seq_net(priv_data);
3984
3985	iter->state.bucket = -`1`;
3986
3987	return ret;
3988	}
3989
3990	static void bpf_iter_fini_udp(void *priv_data)
3991	{
3992	struct bpf_udp_iter_state *iter = priv_data;
3993
3994	bpf_iter_fini_seq_net(priv_data);
3995	kvfree(iter->batch);
3996	}
3997
3998	static const struct bpf_iter_seq_info udp_seq_info = {
3999	.seq_ops = &bpf_iter_udp_seq_ops,
4000	.init_seq_private = bpf_iter_init_udp,
4001	.fini_seq_private = bpf_iter_fini_udp,
4002	.seq_priv_size = sizeof(struct bpf_udp_iter_state),
4003	};
4004
4005	static struct bpf_iter_reg udp_reg_info = {
4006	.target = "udp",
4007	.ctx_arg_info_size = `1`,
4008	.ctx_arg_info = {
4009	{ offsetof(struct bpf_iter__udp, udp_sk),
4010	PTR_TO_BTF_ID_OR_NULL \| PTR_TRUSTED },
4011	},
4012	.seq_info = &udp_seq_info,
4013	};
4014
4015	static void __init bpf_iter_register(void)
4016	{
4017	udp_reg_info.ctx_arg_info[`0`].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UDP];
4018	if (bpf_iter_reg_target(&udp_reg_info))
4019	pr_warn("Warning: could not register bpf iterator udp\n");
4020	}
4021	#endif
4022
4023	void __init udp_init(void)
4024	{
4025	unsigned long limit;
4026
4027	udp_table_init(table: &udp_table, name: "UDP");
4028	limit = nr_free_buffer_pages() / `8`;
4029	limit = max(limit, `128UL`);
4030	sysctl_udp_mem[`0`] = limit / `4` * `3`;
4031	sysctl_udp_mem[`1`] = limit;
4032	sysctl_udp_mem[`2`] = sysctl_udp_mem[`0`] * `2`;
4033
4034	if (register_pernet_subsys(&udp_sysctl_ops))
4035	panic(fmt: "UDP: failed to init sysctl parameters.\n");
4036
4037	#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
4038	bpf_iter_register();
4039	#endif
4040	}
4041

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