geneve: fix TOS inheriting for ipv4

stable inclusion
from stable-v5.10.138
commit 2c746ec91de76e095e4f18367dbb5103a6ed09e1
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60QFD

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2c746ec91de76e095e4f18367dbb5103a6ed09e1

--------------------------------

commit b4ab94d6 upstream.

The current code retrieves the TOS field after the lookup
on the ipv4 routing table. The routing process currently
only allows routing based on the original 3 TOS bits, and
not on the full 6 DSCP bits.
As a result the retrieved TOS is cut to the 3 bits.
However for inheriting purposes the full 6 bits should be used.

Extract the full 6 bits before the route lookup and use
that instead of the cut off 3 TOS bits.

Fixes: e305ac6c ("geneve: Add support to collect tunnel metadata.")
Signed-off-by: NMatthias May <matthias.may@westermo.com>
Acked-by: NGuillaume Nault <gnault@redhat.com>
Link: https://lore.kernel.org/r/20220805190006.8078-1-matthias.may@westermo.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>

drivers/net/geneve.c

@@ -772,7 +772,8 @@ static struct rtable *geneve_get_v4_rt(struct sk_buff *skb,
 				       struct geneve_sock *gs4,
 				       struct flowi4 *fl4,
 				       const struct ip_tunnel_info *info,
-				       __be16 dport, __be16 sport)
+				       __be16 dport, __be16 sport,
+				       __u8 *full_tos)
 {
 	bool use_cache = ip_tunnel_dst_cache_usable(skb, info);
 	struct geneve_dev *geneve = netdev_priv(dev);
@@ -797,6 +798,8 @@ static struct rtable *geneve_get_v4_rt(struct sk_buff *skb,
 		use_cache = false;
 	}
 	fl4->flowi4_tos = RT_TOS(tos);
+	if (full_tos)
+		*full_tos = tos;
 
 	dst_cache = (struct dst_cache *)&info->dst_cache;
 	if (use_cache) {
@@ -884,6 +887,7 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	const struct ip_tunnel_key *key = &info->key;
 	struct rtable *rt;
 	struct flowi4 fl4;
+	__u8 full_tos;
 	__u8 tos, ttl;
 	__be16 df = 0;
 	__be16 sport;
@@ -894,7 +898,7 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 
 	sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);
 	rt = geneve_get_v4_rt(skb, dev, gs4, &fl4, info,
-			      geneve->cfg.info.key.tp_dst, sport);
+			      geneve->cfg.info.key.tp_dst, sport, &full_tos);
 	if (IS_ERR(rt))
 		return PTR_ERR(rt);
 
@@ -938,7 +942,7 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 
 		df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;
 	} else {
-		tos = ip_tunnel_ecn_encap(fl4.flowi4_tos, ip_hdr(skb), skb);
+		tos = ip_tunnel_ecn_encap(full_tos, ip_hdr(skb), skb);
 		if (geneve->cfg.ttl_inherit)
 			ttl = ip_tunnel_get_ttl(ip_hdr(skb), skb);
 		else
@@ -1120,7 +1124,7 @@ static int geneve_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
 					  1, USHRT_MAX, true);
 
 		rt = geneve_get_v4_rt(skb, dev, gs4, &fl4, info,
-				      geneve->cfg.info.key.tp_dst, sport);
+				      geneve->cfg.info.key.tp_dst, sport, NULL);
 		if (IS_ERR(rt))
 			return PTR_ERR(rt);