LXR linux/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
   8static int ip_metrics_convert(struct net *net, struct nlattr *fc_mx,
   9                              int fc_mx_len, u32 *metrics,
  10                              struct netlink_ext_ack *extack)
  11{
  12        bool ecn_ca = false;
  13        struct nlattr *nla;
  14        int remaining;
  15
  16        if (!fc_mx)
  17                return 0;
  18
  19        nla_for_each_attr(nla, fc_mx, fc_mx_len, remaining) {
  20                int type = nla_type(nla);
  21                u32 val;
  22
  23                if (!type)
  24                        continue;
  25                if (type > RTAX_MAX) {
  26                        NL_SET_ERR_MSG(extack, "Invalid metric type");
  27                        return -EINVAL;
  28                }
  29
  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