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From:   Beniamino Galvani <b.galvani@gmail.com>
To:     netdev@vger.kernel.org
Cc:     "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        David Ahern <dsahern@kernel.org>,
        Guillaume Nault <gnault@redhat.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH net-next] bareudp: use ports to lookup route
Date:   Wed, 25 Oct 2023 11:44:41 +0200
Message-ID: <20231025094441.417464-1-b.galvani@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The source and destination ports should be taken into account when
determining the route destination; they can affect the result, for
example in case there are routing rules defined.

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
---
 drivers/net/bareudp.c | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c
index 9c11a0d0273b..31377bb1cc97 100644
--- a/drivers/net/bareudp.c
+++ b/drivers/net/bareudp.c
@@ -306,8 +306,11 @@ static int bareudp_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	if (!sock)
 		return -ESHUTDOWN;
 
+	sport = udp_flow_src_port(bareudp->net, skb,
+				  bareudp->sport_min, USHRT_MAX,
+				  true);
 	rt = udp_tunnel_dst_lookup(skb, dev, bareudp->net, 0, &saddr, &info->key,
-				   0, 0, key->tos,
+				   sport, bareudp->port, key->tos,
 				   use_cache ?
 				   (struct dst_cache *)&info->dst_cache : NULL);
 
@@ -317,9 +320,6 @@ static int bareudp_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	skb_tunnel_check_pmtu(skb, &rt->dst,
 			      BAREUDP_IPV4_HLEN + info->options_len, false);
 
-	sport = udp_flow_src_port(bareudp->net, skb,
-				  bareudp->sport_min, USHRT_MAX,
-				  true);
 	tos = ip_tunnel_ecn_encap(key->tos, ip_hdr(skb), skb);
 	ttl = key->ttl;
 	df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;
@@ -371,8 +371,11 @@ static int bareudp6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	if (!sock)
 		return -ESHUTDOWN;
 
+	sport = udp_flow_src_port(bareudp->net, skb,
+				  bareudp->sport_min, USHRT_MAX,
+				  true);
 	dst = udp_tunnel6_dst_lookup(skb, dev, bareudp->net, sock, 0, &saddr,
-				     key, 0, 0, key->tos,
+				     key, sport, bareudp->port, key->tos,
 				     use_cache ?
 				     (struct dst_cache *) &info->dst_cache : NULL);
 	if (IS_ERR(dst))
@@ -381,9 +384,6 @@ static int bareudp6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	skb_tunnel_check_pmtu(skb, dst, BAREUDP_IPV6_HLEN + info->options_len,
 			      false);
 
-	sport = udp_flow_src_port(bareudp->net, skb,
-				  bareudp->sport_min, USHRT_MAX,
-				  true);
 	prio = ip_tunnel_ecn_encap(key->tos, ip_hdr(skb), skb);
 	ttl = key->ttl;
 
@@ -480,15 +480,20 @@ static int bareudp_fill_metadata_dst(struct net_device *dev,
 	struct ip_tunnel_info *info = skb_tunnel_info(skb);
 	struct bareudp_dev *bareudp = netdev_priv(dev);
 	bool use_cache;
+	__be16 sport;
 
 	use_cache = ip_tunnel_dst_cache_usable(skb, info);
+	sport = udp_flow_src_port(bareudp->net, skb,
+				  bareudp->sport_min, USHRT_MAX,
+				  true);
 
 	if (!ipv6_mod_enabled() || ip_tunnel_info_af(info) == AF_INET) {
 		struct rtable *rt;
 		__be32 saddr;
 
 		rt = udp_tunnel_dst_lookup(skb, dev, bareudp->net, 0, &saddr,
-					   &info->key, 0, 0, info->key.tos,
+					   &info->key, sport, bareudp->port,
+					   info->key.tos,
 					   use_cache ? &info->dst_cache : NULL);
 		if (IS_ERR(rt))
 			return PTR_ERR(rt);
@@ -502,7 +507,7 @@ static int bareudp_fill_metadata_dst(struct net_device *dev,
 
 		dst = udp_tunnel6_dst_lookup(skb, dev, bareudp->net, sock,
 					     0, &saddr, &info->key,
-					     0, 0, info->key.tos,
+					     sport, bareudp->port, info->key.tos,
 					     use_cache ? &info->dst_cache : NULL);
 		if (IS_ERR(dst))
 			return PTR_ERR(dst);
@@ -513,9 +518,7 @@ static int bareudp_fill_metadata_dst(struct net_device *dev,
 		return -EINVAL;
 	}
 
-	info->key.tp_src = udp_flow_src_port(bareudp->net, skb,
-					     bareudp->sport_min,
-			USHRT_MAX, true);
+	info->key.tp_src = sport;
 	info->key.tp_dst = bareudp->port;
 	return 0;
 }
-- 
2.41.0