[PATCH RFC net-next 01/20] net: Move fib_convert_metrics to dst core

[David Ahern <dsahern@gmail.com>]

Move logic of fib_convert_metrics into dst_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 only; it involvesthe following changes to
variable names:
  - fi->fib_net becomes net
  - fc_mx and fc_mx_len are passed as inputs pulled from cfg
  - metrics array is passed as an input from fi->fib_metrics->metrics

Signed-off-by: David Ahern <dsahern@gmail.com>
---
 include/net/dst.h        |  3 +++
 net/core/dst.c           | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 net/ipv4/fib_semantics.c | 43 ++-----------------------------------------
 3 files changed, 53 insertions(+), 41 deletions(-)

diff --git a/include/net/dst.h b/include/net/dst.h
index c63d2c37f6e9..36fa8c894c65 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -193,6 +193,9 @@ static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
 		p[metric-1] = val;
 }
 
+int dst_metrics_convert(struct net *net, struct nlattr *fc_mx, int fc_mx_len,
+			u32 *metrics);
+
 /* Kernel-internal feature bits that are unallocated in user space. */
 #define DST_FEATURE_ECN_CA	(1 << 31)
 
diff --git a/net/core/dst.c b/net/core/dst.c
index 007aa0b08291..5f70bc832bec 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -21,6 +21,7 @@
 #include <linux/sched.h>
 #include <linux/prefetch.h>
 #include <net/lwtunnel.h>
+#include <net/tcp.h>
 #include <net/xfrm.h>
 
 #include <net/dst.h>
@@ -248,6 +249,53 @@ void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
 }
 EXPORT_SYMBOL(__dst_destroy_metrics_generic);
 
+int dst_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(dst_metrics_convert);
+
 static struct dst_ops md_dst_ops = {
 	.family =		AF_UNSPEC,
 };
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index cd46d7666598..db48d719b2b4 100644
--- a/net/ipv4/fib_semantics.c
+++ b/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 dst_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,
-- 
2.11.0