net: fib: move metrics parsing to a helper

fib_create_info() is already quite large, so before adding more
code to the metrics section move that to a helper, similar to
ip6_convert_metrics.

Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 1b2d01170a4de8665b0bc5bedbb596058f15e41c..88afbae893f0d40a4295dc8d14d026c918b4930e 100644 (file)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -876,6 +876,44 @@ static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
        return true;
 }
 
+static int
+fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
+{
+       struct nlattr *nla;
+       int remaining;
+
+       if (!cfg->fc_mx)
+               return 0;
+
+       nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
+               int type = nla_type(nla);
+               u32 val;
+
+               if (!type)
+                       continue;
+               if (type > RTAX_MAX)
+                       return -EINVAL;
+
+               if (type == RTAX_CC_ALGO) {
+                       char tmp[TCP_CA_NAME_MAX];
+
+                       nla_strlcpy(tmp, nla, sizeof(tmp));
+                       val = tcp_ca_get_key_by_name(tmp);
+                       if (val == TCP_CA_UNSPEC)
+                               return -EINVAL;
+               } else {
+                       val = nla_get_u32(nla);
+               }
+               if (type == RTAX_ADVMSS && val > 65535 - 40)
+                       val = 65535 - 40;
+               if (type == RTAX_MTU && val > 65535 - 15)
+                       val = 65535 - 15;
+               fi->fib_metrics[type - 1] = val;
+       }
+
+       return 0;
+}
+
 struct fib_info *fib_create_info(struct fib_config *cfg)
 {
        int err;
@@ -948,36 +986,9 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
                        goto failure;
        } endfor_nexthops(fi)
 
-       if (cfg->fc_mx) {
-               struct nlattr *nla;
-               int remaining;
-
-               nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
-                       int type = nla_type(nla);
-
-                       if (type) {
-                               u32 val;
-
-                               if (type > RTAX_MAX)
-                                       goto err_inval;
-                               if (type == RTAX_CC_ALGO) {
-                                       char tmp[TCP_CA_NAME_MAX];
-
-                                       nla_strlcpy(tmp, nla, sizeof(tmp));
-                                       val = tcp_ca_get_key_by_name(tmp);
-                                       if (val == TCP_CA_UNSPEC)
-                                               goto err_inval;
-                               } else {
-                                       val = nla_get_u32(nla);
-                               }
-                               if (type == RTAX_ADVMSS && val > 65535 - 40)
-                                       val = 65535 - 40;
-                               if (type == RTAX_MTU && val > 65535 - 15)
-                                       val = 65535 - 15;
-                               fi->fib_metrics[type - 1] = val;
-                       }
-               }
-       }
+       err = fib_convert_metrics(fi, cfg);
+       if (err)
+               goto failure;
 
        if (cfg->fc_mp) {
 #ifdef CONFIG_IP_ROUTE_MULTIPATH