Merge branch 'ipv4-fix-incorrect-tos-in-route-get-reply'

Ido Schimmel says:

====================
ipv4: Fix incorrect TOS in route get reply

Two small fixes for incorrect TOS in route get reply. See more details
in the commit messages.

No regressions in FIB tests:

 # ./fib_tests.sh
 [...]
 Tests passed: 218
 Tests failed:   0
====================

Link: https://patch.msgid.link/20240715142354.3697987-1-idosch@nvidia.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

include/net/ip_fib.h

@@ -173,6 +173,7 @@ struct fib_result {
 	unsigned char		type;
 	unsigned char		scope;
 	u32			tclassid;
+	dscp_t			dscp;
 	struct fib_nh_common	*nhc;
 	struct fib_info		*fi;
 	struct fib_table	*table;

net/ipv4/fib_trie.c

@@ -1629,6 +1629,7 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 			res->nhc = nhc;
 			res->type = fa->fa_type;
 			res->scope = fi->fib_scope;
+			res->dscp = fa->fa_dscp;
 			res->fi = fi;
 			res->table = tb;
 			res->fa_head = &n->leaf;

net/ipv4/route.c

@@ -2867,9 +2867,9 @@ EXPORT_SYMBOL_GPL(ip_route_output_flow);
 
 /* called with rcu_read_lock held */
 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
-			struct rtable *rt, u32 table_id, struct flowi4 *fl4,
-			struct sk_buff *skb, u32 portid, u32 seq,
-			unsigned int flags)
+			struct rtable *rt, u32 table_id, dscp_t dscp,
+			struct flowi4 *fl4, struct sk_buff *skb, u32 portid,
+			u32 seq, unsigned int flags)
 {
 	struct rtmsg *r;
 	struct nlmsghdr *nlh;
@@ -2885,7 +2885,7 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
 	r->rtm_family	 = AF_INET;
 	r->rtm_dst_len	= 32;
 	r->rtm_src_len	= 0;
-	r->rtm_tos	= fl4 ? fl4->flowi4_tos : 0;
+	r->rtm_tos	= inet_dscp_to_dsfield(dscp);
 	r->rtm_table	= table_id < 256 ? table_id : RT_TABLE_COMPAT;
 	if (nla_put_u32(skb, RTA_TABLE, table_id))
 		goto nla_put_failure;
@@ -3035,7 +3035,7 @@ static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
 				goto next;
 
 			err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
-					   table_id, NULL, skb,
+					   table_id, 0, NULL, skb,
 					   NETLINK_CB(cb->skb).portid,
 					   cb->nlh->nlmsg_seq, flags);
 			if (err)
@@ -3331,7 +3331,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 		fri.tb_id = table_id;
 		fri.dst = res.prefix;
 		fri.dst_len = res.prefixlen;
-		fri.dscp = inet_dsfield_to_dscp(fl4.flowi4_tos);
+		fri.dscp = res.dscp;
 		fri.type = rt->rt_type;
 		fri.offload = 0;
 		fri.trap = 0;
@@ -3358,8 +3358,8 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 		err = fib_dump_info(skb, NETLINK_CB(in_skb).portid,
 				    nlh->nlmsg_seq, RTM_NEWROUTE, &fri, 0);
 	} else {
-		err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
-				   NETLINK_CB(in_skb).portid,
+		err = rt_fill_info(net, dst, src, rt, table_id, res.dscp, &fl4,
+				   skb, NETLINK_CB(in_skb).portid,
 				   nlh->nlmsg_seq, 0);
 	}
 	if (err < 0)

tools/testing/selftests/net/fib_tests.sh

@@ -1737,53 +1737,53 @@ ipv4_rt_dsfield()
 
 	# DSCP 0x10 should match the specific route, no matter the ECN bits
 	$IP route get fibmatch 172.16.102.1 dsfield 0x10 | \
-		grep -q "via 172.16.103.2"
+		grep -q "172.16.102.0/24 tos 0x10 via 172.16.103.2"
 	log_test $? 0 "IPv4 route with DSCP and ECN:Not-ECT"
 
 	$IP route get fibmatch 172.16.102.1 dsfield 0x11 | \
-		grep -q "via 172.16.103.2"
+		grep -q "172.16.102.0/24 tos 0x10 via 172.16.103.2"
 	log_test $? 0 "IPv4 route with DSCP and ECN:ECT(1)"
 
 	$IP route get fibmatch 172.16.102.1 dsfield 0x12 | \
-		grep -q "via 172.16.103.2"
+		grep -q "172.16.102.0/24 tos 0x10 via 172.16.103.2"
 	log_test $? 0 "IPv4 route with DSCP and ECN:ECT(0)"
 
 	$IP route get fibmatch 172.16.102.1 dsfield 0x13 | \
-		grep -q "via 172.16.103.2"
+		grep -q "172.16.102.0/24 tos 0x10 via 172.16.103.2"
 	log_test $? 0 "IPv4 route with DSCP and ECN:CE"
 
 	# Unknown DSCP should match the generic route, no matter the ECN bits
 	$IP route get fibmatch 172.16.102.1 dsfield 0x14 | \
-		grep -q "via 172.16.101.2"
+		grep -q "172.16.102.0/24 via 172.16.101.2"
 	log_test $? 0 "IPv4 route with unknown DSCP and ECN:Not-ECT"
 
 	$IP route get fibmatch 172.16.102.1 dsfield 0x15 | \
-		grep -q "via 172.16.101.2"
+		grep -q "172.16.102.0/24 via 172.16.101.2"
 	log_test $? 0 "IPv4 route with unknown DSCP and ECN:ECT(1)"
 
 	$IP route get fibmatch 172.16.102.1 dsfield 0x16 | \
-		grep -q "via 172.16.101.2"
+		grep -q "172.16.102.0/24 via 172.16.101.2"
 	log_test $? 0 "IPv4 route with unknown DSCP and ECN:ECT(0)"
 
 	$IP route get fibmatch 172.16.102.1 dsfield 0x17 | \
-		grep -q "via 172.16.101.2"
+		grep -q "172.16.102.0/24 via 172.16.101.2"
 	log_test $? 0 "IPv4 route with unknown DSCP and ECN:CE"
 
 	# Null DSCP should match the generic route, no matter the ECN bits
 	$IP route get fibmatch 172.16.102.1 dsfield 0x00 | \
-		grep -q "via 172.16.101.2"
+		grep -q "172.16.102.0/24 via 172.16.101.2"
 	log_test $? 0 "IPv4 route with no DSCP and ECN:Not-ECT"
 
 	$IP route get fibmatch 172.16.102.1 dsfield 0x01 | \
-		grep -q "via 172.16.101.2"
+		grep -q "172.16.102.0/24 via 172.16.101.2"
 	log_test $? 0 "IPv4 route with no DSCP and ECN:ECT(1)"
 
 	$IP route get fibmatch 172.16.102.1 dsfield 0x02 | \
-		grep -q "via 172.16.101.2"
+		grep -q "172.16.102.0/24 via 172.16.101.2"
 	log_test $? 0 "IPv4 route with no DSCP and ECN:ECT(0)"
 
 	$IP route get fibmatch 172.16.102.1 dsfield 0x03 | \
-		grep -q "via 172.16.101.2"
+		grep -q "172.16.102.0/24 via 172.16.101.2"
 	log_test $? 0 "IPv4 route with no DSCP and ECN:CE"
 }