net/ipv4/metrics.c

   1 #include <linux/netlink.h>
   2 #include <linux/rtnetlink.h>
   3 #include <linux/types.h>
   4 #include <net/ip.h>
   5 #include <net/net_namespace.h>
   6 #include <net/tcp.h>
   7
   8 static int ip_metrics_convert(struct net *net, struct nlattr *fc_mx,
   9                               int fc_mx_len, u32 *metrics)
  10 {
  11         bool ecn_ca = false;
  12         struct nlattr *nla;
  13         int remaining;
  14
  15         if (!fc_mx)
  16                 return 0;
  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                         return -EINVAL;
  26
  27                 if (type == RTAX_CC_ALGO) {
  28                         char tmp[TCP_CA_NAME_MAX];
  29
  30                         nla_strlcpy(tmp, nla, sizeof(tmp));
  31                         val = tcp_ca_get_key_by_name(net, tmp, &ecn_ca);
  32                         if (val == TCP_CA_UNSPEC)
  33                                 return -EINVAL;
  34                 } else {
  35                         if (nla_len(nla) != sizeof(u32))
  36                                 return -EINVAL;
  37                         val = nla_get_u32(nla);
  38                 }
  39                 if (type == RTAX_ADVMSS && val > 65535 - 40)
  40                         val = 65535 - 40;
  41                 if (type == RTAX_MTU && val > 65535 - 15)
  42                         val = 65535 - 15;
  43                 if (type == RTAX_HOPLIMIT && val > 255)
  44                         val = 255;
  45                 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
  46                         return -EINVAL;
  47                 metrics[type - 1] = val;
  48         }
  49
  50         if (ecn_ca)
  51                 metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
  52
  53         return 0;
  54 }
  55
  56 struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
  57                                         int fc_mx_len)
  58 {
  59         struct dst_metrics *fib_metrics;
  60         int err;
  61
  62         if (!fc_mx)
  63                 return (struct dst_metrics *)&dst_default_metrics;
  64
  65         fib_metrics = kzalloc(sizeof(*fib_metrics), GFP_KERNEL);
  66         if (unlikely(!fib_metrics))
  67                 return ERR_PTR(-ENOMEM);
  68
  69         err = ip_metrics_convert(net, fc_mx, fc_mx_len, fib_metrics->metrics);
  70         if (!err) {
  71                 refcount_set(&fib_metrics->refcnt, 1);
  72         } else {
  73                 kfree(fib_metrics);
  74                 fib_metrics = ERR_PTR(err);
  75         }
  76
  77         return fib_metrics;
  78 }
  79 EXPORT_SYMBOL_GPL(ip_fib_metrics_init);