net: fib_rules: Add new attribute to set protocol

For ages iproute2 has used `struct rtmsg` as the ancillary header for
FIB rules and in the process set the protocol value to RTPROT_BOOT.
Until ca56209a66 ("net: Allow a rule to track originating protocol")
the kernel rules code ignored the protocol value sent from userspace
and always returned 0 in notifications. To avoid incompatibility with
existing iproute2, send the protocol as a new attribute.

Fixes: cac56209a66 ("net: Allow a rule to track originating protocol")
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 88298f1..a6aea80 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -466,11 +466,13 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 	}
 	refcount_set(&rule->refcnt, 1);
 	rule->fr_net = net;
-	rule->proto = frh->proto;
 
 	rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
 	                              : fib_default_rule_pref(ops);
 
+	rule->proto = tb[FRA_PROTOCOL] ?
+		nla_get_u8(tb[FRA_PROTOCOL]) : RTPROT_UNSPEC;
+
 	if (tb[FRA_IIFNAME]) {
 		struct net_device *dev;
 
@@ -666,7 +668,8 @@ int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 	}
 
 	list_for_each_entry(rule, &ops->rules_list, list) {
-		if (frh->proto && (frh->proto != rule->proto))
+		if (tb[FRA_PROTOCOL] &&
+		    (rule->proto != nla_get_u8(tb[FRA_PROTOCOL])))
 			continue;
 
 		if (frh->action && (frh->action != rule->action))
@@ -786,7 +789,8 @@ static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
 			 + nla_total_size(4) /* FRA_FWMARK */
 			 + nla_total_size(4) /* FRA_FWMASK */
 			 + nla_total_size_64bit(8) /* FRA_TUN_ID */
-			 + nla_total_size(sizeof(struct fib_kuid_range));
+			 + nla_total_size(sizeof(struct fib_kuid_range))
+			 + nla_total_size(1); /* FRA_PROTOCOL */
 
 	if (ops->nlmsg_payload)
 		payload += ops->nlmsg_payload(rule);
@@ -813,9 +817,12 @@ static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 	if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
 		goto nla_put_failure;
 	frh->res1 = 0;
+	frh->res2 = 0;
 	frh->action = rule->action;
 	frh->flags = rule->flags;
-	frh->proto = rule->proto;
+
+	if (nla_put_u8(skb, FRA_PROTOCOL, rule->proto))
+		goto nla_put_failure;
 
 	if (rule->action == FR_ACT_GOTO &&
 	    rcu_access_pointer(rule->ctarget) == NULL)