net/ipv4/metrics.c

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