LXR linux/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
   9static 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
  67struct 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}
  92EXPORT_SYMBOL_GPL(ip_fib_metrics_init);
  93