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 net *net, 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(tmp, nla, sizeof(tmp));
34			val = tcp_ca_get_key_by_name(net, tmp, &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 net *net, 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(-ENOMEM);
79
80	err = ip_metrics_convert(net, fc_mx, fc_mx_len, fib_metrics->metrics,
81				 extack);
82	if (!err) {
83		refcount_set(&fib_metrics->refcnt, 1);
84	} else {
85		kfree(fib_metrics);
86		fib_metrics = ERR_PTR(err);
87	}
88
89	return fib_metrics;
90}
91EXPORT_SYMBOL_GPL(ip_fib_metrics_init);
92