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 
ip_metrics_convert(struct net * net,struct nlattr * fc_mx,int fc_mx_len,u32 * metrics,struct netlink_ext_ack * extack)10 static 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 
ip_fib_metrics_init(struct net * net,struct nlattr * fc_mx,int fc_mx_len,struct netlink_ext_ack * extack)66 struct 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 }
91 EXPORT_SYMBOL_GPL(ip_fib_metrics_init);
92