net: Add extack argument to ip_fib_metrics_init

Add extack argument to ip_fib_metrics_init and add messages for invalid
metrics.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip.h

@@ -421,7 +421,8 @@ static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
 }
 
 struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
-					int fc_mx_len);
+					int fc_mx_len,
+					struct netlink_ext_ack *extack);
 static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
 {
 	if (fib_metrics != &dst_default_metrics &&

net/ipv4/fib_semantics.c

@@ -1076,7 +1076,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
 	if (!fi)
 		goto failure;
 	fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
-					      cfg->fc_mx_len);
+					      cfg->fc_mx_len, extack);
 	if (unlikely(IS_ERR(fi->fib_metrics))) {
 		err = PTR_ERR(fi->fib_metrics);
 		kfree(fi);

net/ipv4/metrics.c

@@ -6,7 +6,8 @@
 #include <net/tcp.h>
 
 static int ip_metrics_convert(struct net *net, struct nlattr *fc_mx,
-			      int fc_mx_len, u32 *metrics)
+			      int fc_mx_len, u32 *metrics,
+			      struct netlink_ext_ack *extack)
 {
 	bool ecn_ca = false;
 	struct nlattr *nla;
@@ -21,19 +22,26 @@ static int ip_metrics_convert(struct net *net, struct nlattr *fc_mx,
 
 		if (!type)
 			continue;
-		if (type > RTAX_MAX)
+		if (type > RTAX_MAX) {
+			NL_SET_ERR_MSG(extack, "Invalid metric type");
 			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)
+			if (val == TCP_CA_UNSPEC) {
+				NL_SET_ERR_MSG(extack, "Unknown tcp congestion algorithm");
 				return -EINVAL;
+			}
 		} else {
-			if (nla_len(nla) != sizeof(u32))
+			if (nla_len(nla) != sizeof(u32)) {
+				NL_SET_ERR_MSG_ATTR(extack, nla,
+						    "Invalid attribute in metrics");
 				return -EINVAL;
+			}
 			val = nla_get_u32(nla);
 		}
 		if (type == RTAX_ADVMSS && val > 65535 - 40)
@@ -42,8 +50,10 @@ static int ip_metrics_convert(struct net *net, struct nlattr *fc_mx,
 			val = 65535 - 15;
 		if (type == RTAX_HOPLIMIT && val > 255)
 			val = 255;
-		if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
+		if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) {
+			NL_SET_ERR_MSG(extack, "Unknown flag set in feature mask in metrics attribute");
 			return -EINVAL;
+		}
 		metrics[type - 1] = val;
 	}
 
@@ -54,7 +64,8 @@ static int ip_metrics_convert(struct net *net, struct nlattr *fc_mx,
 }
 
 struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
-					int fc_mx_len)
+					int fc_mx_len,
+					struct netlink_ext_ack *extack)
 {
 	struct dst_metrics *fib_metrics;
 	int err;
@@ -66,7 +77,8 @@ struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
 	if (unlikely(!fib_metrics))
 		return ERR_PTR(-ENOMEM);
 
-	err = ip_metrics_convert(net, fc_mx, fc_mx_len, fib_metrics->metrics);
+	err = ip_metrics_convert(net, fc_mx, fc_mx_len, fib_metrics->metrics,
+				 extack);
 	if (!err) {
 		refcount_set(&fib_metrics->refcnt, 1);
 	} else {

net/ipv6/route.c

@@ -2975,7 +2975,8 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
 	if (!rt)
 		goto out;
 
-	rt->fib6_metrics = ip_fib_metrics_init(net, cfg->fc_mx, cfg->fc_mx_len);
+	rt->fib6_metrics = ip_fib_metrics_init(net, cfg->fc_mx, cfg->fc_mx_len,
+					       extack);
 	if (IS_ERR(rt->fib6_metrics)) {
 		err = PTR_ERR(rt->fib6_metrics);
 		/* Do not leave garbage there. */
@@ -3708,7 +3709,7 @@ struct fib6_info *addrconf_f6i_alloc(struct net *net,
 	if (!f6i)
 		return ERR_PTR(-ENOMEM);
 
-	f6i->fib6_metrics = ip_fib_metrics_init(net, NULL, 0);
+	f6i->fib6_metrics = ip_fib_metrics_init(net, NULL, 0, NULL);
 	f6i->dst_nocount = true;
 	f6i->dst_host = true;
 	f6i->fib6_protocol = RTPROT_KERNEL;