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>

1 files changed, 53 insertions, 0 deletions

diff --git a/net/ipv4/metrics.c b/net/ipv4/metrics.c
new file mode 100644
index 000000000000..5121c6475e6b
--- /dev/null
+++ b/net/ipv4/metrics.c
@@ -0,0 +1,53 @@
+#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);