1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/netlink.h>
3#include <linux/nospec.h>
4#include <linux/rtnetlink.h>
5#include <linux/types.h>
6#include <net/ip.h>
7#include <net/net_namespace.h>
8#include <net/tcp.h>
9
10static int ip_metrics_convert(struct nlattr *fc_mx,
11 int fc_mx_len, u32 *metrics,
12 struct netlink_ext_ack *extack)
13{
14 bool ecn_ca = false;
15 struct nlattr *nla;
16 int remaining;
17
18 nla_for_each_attr(nla, fc_mx, fc_mx_len, remaining) {
19 int type = nla_type(nla);
20 u32 val;
21
22 if (!type)
23 continue;
24 if (type > RTAX_MAX) {
25 NL_SET_ERR_MSG(extack, "Invalid metric type");
26 return -EINVAL;
27 }
28
29 type = array_index_nospec(type, RTAX_MAX + 1);
30 if (type == RTAX_CC_ALGO) {
31 char tmp[TCP_CA_NAME_MAX];
32
33 nla_strscpy(dst: tmp, nla, dstsize: sizeof(tmp));
34 val = tcp_ca_get_key_by_name(name: tmp, ecn_ca: &ecn_ca);
35 if (val == TCP_CA_UNSPEC) {
36 NL_SET_ERR_MSG(extack, "Unknown tcp congestion algorithm");
37 return -EINVAL;
38 }
39 } else {
40 if (nla_len(nla) != sizeof(u32)) {
41 NL_SET_ERR_MSG_ATTR(extack, nla,
42 "Invalid attribute in metrics");
43 return -EINVAL;
44 }
45 val = nla_get_u32(nla);
46 }
47 if (type == RTAX_ADVMSS && val > 65535 - 40)
48 val = 65535 - 40;
49 if (type == RTAX_MTU && val > 65535 - 15)
50 val = 65535 - 15;
51 if (type == RTAX_HOPLIMIT && val > 255)
52 val = 255;
53 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) {
54 NL_SET_ERR_MSG(extack, "Unknown flag set in feature mask in metrics attribute");
55 return -EINVAL;
56 }
57 metrics[type - 1] = val;
58 }
59
60 if (ecn_ca)
61 metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
62
63 return 0;
64}
65
66struct dst_metrics *ip_fib_metrics_init(struct nlattr *fc_mx,
67 int fc_mx_len,
68 struct netlink_ext_ack *extack)
69{
70 struct dst_metrics *fib_metrics;
71 int err;
72
73 if (!fc_mx)
74 return (struct dst_metrics *)&dst_default_metrics;
75
76 fib_metrics = kzalloc(sizeof(*fib_metrics), GFP_KERNEL);
77 if (unlikely(!fib_metrics))
78 return ERR_PTR(error: -ENOMEM);
79
80 err = ip_metrics_convert(fc_mx, fc_mx_len, metrics: fib_metrics->metrics,
81 extack);
82 if (!err) {
83 refcount_set(r: &fib_metrics->refcnt, n: 1);
84 } else {
85 kfree(objp: fib_metrics);
86 fib_metrics = ERR_PTR(error: err);
87 }
88
89 return fib_metrics;
90}
91EXPORT_SYMBOL_GPL(ip_fib_metrics_init);
92