net: Move fib_convert_metrics to metrics file

Move logic of fib_convert_metrics into ip_metrics_convert. This allows
the code that converts netlink attributes into metrics struct to be
re-used in a later patch by IPv6.

This is mostly a code move with the following changes to variable names:
  - fi->fib_net becomes net
  - fc_mx and fc_mx_len are passed as inputs pulled from fib_config
  - metrics array is passed as an input from fi->fib_metrics->metrics
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip.h

@@ -396,6 +396,9 @@ static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
 	return min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
 }
 
+int ip_metrics_convert(struct net *net, struct nlattr *fc_mx, int fc_mx_len,
+		       u32 *metrics);
+
 u32 ip_idents_reserve(u32 hash, int segs);
 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
 

net/ipv4/Makefile

@@ -13,7 +13,8 @@ obj-y     := route.o inetpeer.o protocol.o \
 	     tcp_offload.o datagram.o raw.o udp.o udplite.o \
 	     udp_offload.o arp.o icmp.o devinet.o af_inet.o igmp.o \
 	     fib_frontend.o fib_semantics.o fib_trie.o fib_notifier.o \
-	     inet_fragment.o ping.o ip_tunnel_core.o gre_offload.o
+	     inet_fragment.o ping.o ip_tunnel_core.o gre_offload.o \
+	     metrics.o
 
 obj-$(CONFIG_NET_IP_TUNNEL) += ip_tunnel.o
 obj-$(CONFIG_SYSCTL) += sysctl_net_ipv4.o

net/ipv4/fib_semantics.c

@@ -1019,47 +1019,8 @@ static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
 static int
 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
 {
-	bool ecn_ca = false;
-	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(fi->fib_net, tmp, &ecn_ca);
-			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;
-		if (type == RTAX_HOPLIMIT && val > 255)
-			val = 255;
-		if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
-			return -EINVAL;
-		fi->fib_metrics->metrics[type - 1] = val;
-	}
-
-	if (ecn_ca)
-		fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
-
-	return 0;
+	return ip_metrics_convert(fi->fib_net, cfg->fc_mx, cfg->fc_mx_len,
+				  fi->fib_metrics->metrics);
 }
 
 struct fib_info *fib_create_info(struct fib_config *cfg,

net/ipv4/metrics.c

+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/types.h>
+#include <net/ip.h>
+#include <net/net_namespace.h>
+#include <net/tcp.h>
+
+int ip_metrics_convert(struct net *net, struct nlattr *fc_mx, int fc_mx_len,
+		       u32 *metrics)
+{
+	bool ecn_ca = false;
+	struct nlattr *nla;
+	int remaining;
+
+	if (!fc_mx)
+		return 0;
+
+	nla_for_each_attr(nla, fc_mx, 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(net, tmp, &ecn_ca);
+			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;
+		if (type == RTAX_HOPLIMIT && val > 255)
+			val = 255;
+		if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
+			return -EINVAL;
+		metrics[type - 1] = val;
+	}
+
+	if (ecn_ca)
+		metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ip_metrics_convert);