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 * Definitions for the UDP protocol.
8 *
9 * Version: @(#)udp.h 1.0.2 04/28/93
10 *
11 * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 */
13#ifndef _LINUX_UDP_H
14#define _LINUX_UDP_H
15
16#include <net/inet_sock.h>
17#include <linux/skbuff.h>
18#include <net/netns/hash.h>
19#include <uapi/linux/udp.h>
20
21static inline struct udphdr *udp_hdr(const struct sk_buff *skb)
22{
23 return (struct udphdr *)skb_transport_header(skb);
24}
25
26#define UDP_HTABLE_SIZE_MIN_PERNET 128
27#define UDP_HTABLE_SIZE_MIN (IS_ENABLED(CONFIG_BASE_SMALL) ? 128 : 256)
28#define UDP_HTABLE_SIZE_MAX 65536
29
30static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask)
31{
32 return (num + net_hash_mix(net)) & mask;
33}
34
35enum {
36 UDP_FLAGS_CORK, /* Cork is required */
37 UDP_FLAGS_NO_CHECK6_TX, /* Send zero UDP6 checksums on TX? */
38 UDP_FLAGS_NO_CHECK6_RX, /* Allow zero UDP6 checksums on RX? */
39 UDP_FLAGS_GRO_ENABLED, /* Request GRO aggregation */
40 UDP_FLAGS_ACCEPT_FRAGLIST,
41 UDP_FLAGS_ACCEPT_L4,
42 UDP_FLAGS_ENCAP_ENABLED, /* This socket enabled encap */
43 UDP_FLAGS_UDPLITE_SEND_CC, /* set via udplite setsockopt */
44 UDP_FLAGS_UDPLITE_RECV_CC, /* set via udplite setsockopt */
45};
46
47/* per NUMA structure for lockless producer usage. */
48struct udp_prod_queue {
49 struct llist_head ll_root ____cacheline_aligned_in_smp;
50 atomic_t rmem_alloc;
51};
52
53struct udp_sock {
54 /* inet_sock has to be the first member */
55 struct inet_sock inet;
56#define udp_port_hash inet.sk.__sk_common.skc_u16hashes[0]
57#define udp_portaddr_hash inet.sk.__sk_common.skc_u16hashes[1]
58#define udp_portaddr_node inet.sk.__sk_common.skc_portaddr_node
59
60 unsigned long udp_flags;
61
62 int pending; /* Any pending frames ? */
63 __u8 encap_type; /* Is this an Encapsulation socket? */
64
65#if !IS_ENABLED(CONFIG_BASE_SMALL)
66 /* For UDP 4-tuple hash */
67 __u16 udp_lrpa_hash;
68 struct hlist_nulls_node udp_lrpa_node;
69#endif
70
71 /*
72 * Following member retains the information to create a UDP header
73 * when the socket is uncorked.
74 */
75 __u16 len; /* total length of pending frames */
76 __u16 gso_size;
77 /*
78 * Fields specific to UDP-Lite.
79 */
80 __u16 pcslen;
81 __u16 pcrlen;
82 /*
83 * For encapsulation sockets.
84 */
85 int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
86 void (*encap_err_rcv)(struct sock *sk, struct sk_buff *skb, int err,
87 __be16 port, u32 info, u8 *payload);
88 int (*encap_err_lookup)(struct sock *sk, struct sk_buff *skb);
89 void (*encap_destroy)(struct sock *sk);
90
91 /* GRO functions for UDP socket */
92 struct sk_buff * (*gro_receive)(struct sock *sk,
93 struct list_head *head,
94 struct sk_buff *skb);
95 int (*gro_complete)(struct sock *sk,
96 struct sk_buff *skb,
97 int nhoff);
98
99 struct udp_prod_queue *udp_prod_queue;
100
101 /* udp_recvmsg try to use this before splicing sk_receive_queue */
102 struct sk_buff_head reader_queue ____cacheline_aligned_in_smp;
103
104 /* This field is dirtied by udp_recvmsg() */
105 int forward_deficit;
106
107 /* This fields follows rcvbuf value, and is touched by udp_recvmsg */
108 int forward_threshold;
109
110 /* Cache friendly copy of sk->sk_peek_off >= 0 */
111 bool peeking_with_offset;
112
113 /*
114 * Accounting for the tunnel GRO fastpath.
115 * Unprotected by compilers guard, as it uses space available in
116 * the last UDP socket cacheline.
117 */
118 struct hlist_node tunnel_list;
119 struct numa_drop_counters drop_counters;
120};
121
122#define udp_test_bit(nr, sk) \
123 test_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
124#define udp_set_bit(nr, sk) \
125 set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
126#define udp_test_and_set_bit(nr, sk) \
127 test_and_set_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
128#define udp_clear_bit(nr, sk) \
129 clear_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags)
130#define udp_assign_bit(nr, sk, val) \
131 assign_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags, val)
132
133#define UDP_MAX_SEGMENTS (1 << 7UL)
134
135#define udp_sk(ptr) container_of_const(ptr, struct udp_sock, inet.sk)
136
137static inline int udp_set_peek_off(struct sock *sk, int val)
138{
139 sk_set_peek_off(sk, val);
140 WRITE_ONCE(udp_sk(sk)->peeking_with_offset, val >= 0);
141 return 0;
142}
143
144static inline void udp_set_no_check6_tx(struct sock *sk, bool val)
145{
146 udp_assign_bit(NO_CHECK6_TX, sk, val);
147}
148
149static inline void udp_set_no_check6_rx(struct sock *sk, bool val)
150{
151 udp_assign_bit(NO_CHECK6_RX, sk, val);
152}
153
154static inline bool udp_get_no_check6_tx(const struct sock *sk)
155{
156 return udp_test_bit(NO_CHECK6_TX, sk);
157}
158
159static inline bool udp_get_no_check6_rx(const struct sock *sk)
160{
161 return udp_test_bit(NO_CHECK6_RX, sk);
162}
163
164static inline void udp_cmsg_recv(struct msghdr *msg, struct sock *sk,
165 struct sk_buff *skb)
166{
167 int gso_size;
168
169 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
170 gso_size = skb_shinfo(skb)->gso_size;
171 put_cmsg(msg, SOL_UDP, UDP_GRO, len: sizeof(gso_size), data: &gso_size);
172 }
173}
174
175DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
176#if IS_ENABLED(CONFIG_IPV6)
177DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
178#endif
179
180static inline bool udp_encap_needed(void)
181{
182 if (static_branch_unlikely(&udp_encap_needed_key))
183 return true;
184
185#if IS_ENABLED(CONFIG_IPV6)
186 if (static_branch_unlikely(&udpv6_encap_needed_key))
187 return true;
188#endif
189
190 return false;
191}
192
193static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb)
194{
195 if (!skb_is_gso(skb))
196 return false;
197
198 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 &&
199 !udp_test_bit(ACCEPT_L4, sk))
200 return true;
201
202 if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST &&
203 !udp_test_bit(ACCEPT_FRAGLIST, sk))
204 return true;
205
206 /* GSO packets lacking the SKB_GSO_UDP_TUNNEL/_CSUM bits might still
207 * land in a tunnel as the socket check in udp_gro_receive cannot be
208 * foolproof.
209 */
210 if (udp_encap_needed() &&
211 READ_ONCE(udp_sk(sk)->encap_rcv) &&
212 !(skb_shinfo(skb)->gso_type &
213 (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM)))
214 return true;
215
216 return false;
217}
218
219static inline void udp_allow_gso(struct sock *sk)
220{
221 udp_set_bit(ACCEPT_L4, sk);
222 udp_set_bit(ACCEPT_FRAGLIST, sk);
223}
224
225#define udp_portaddr_for_each_entry(__sk, list) \
226 hlist_for_each_entry(__sk, list, __sk_common.skc_portaddr_node)
227
228#define udp_portaddr_for_each_entry_from(__sk) \
229 hlist_for_each_entry_from(__sk, __sk_common.skc_portaddr_node)
230
231#define udp_portaddr_for_each_entry_rcu(__sk, list) \
232 hlist_for_each_entry_rcu(__sk, list, __sk_common.skc_portaddr_node)
233
234#if !IS_ENABLED(CONFIG_BASE_SMALL)
235#define udp_lrpa_for_each_entry_rcu(__up, node, list) \
236 hlist_nulls_for_each_entry_rcu(__up, node, list, udp_lrpa_node)
237#endif
238
239#define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
240
241static inline struct sock *udp_tunnel_sk(const struct net *net, bool is_ipv6)
242{
243#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL)
244 return rcu_dereference(net->ipv4.udp_tunnel_gro[is_ipv6].sk);
245#else
246 return NULL;
247#endif
248}
249
250#endif /* _LINUX_UDP_H */
251