udp_tunnel: Pass UDP socket down through udp_tunnel{, 6}_xmit_skb().

That was we can make sure the output path of ipv4/ipv6 operate on
the UDP socket rather than whatever random thing happens to be in
skb->sk.

Based upon a patch by Jiri Pirko.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>

drivers/net/vxlan.c

@@ -1672,7 +1672,8 @@ static void vxlan_build_gbp_hdr(struct vxlanhdr *vxh, u32 vxflags,
 }
 
 #if IS_ENABLED(CONFIG_IPV6)
-static int vxlan6_xmit_skb(struct dst_entry *dst, struct sk_buff *skb,
+static int vxlan6_xmit_skb(struct dst_entry *dst, struct sock *sk,
+			   struct sk_buff *skb,
 			   struct net_device *dev, struct in6_addr *saddr,
 			   struct in6_addr *daddr, __u8 prio, __u8 ttl,
 			   __be16 src_port, __be16 dst_port,
@@ -1748,7 +1749,7 @@ static int vxlan6_xmit_skb(struct dst_entry *dst, struct sk_buff *skb,
 
 	skb_set_inner_protocol(skb, htons(ETH_P_TEB));
 
-	udp_tunnel6_xmit_skb(dst, skb, dev, saddr, daddr, prio,
+	udp_tunnel6_xmit_skb(dst, sk, skb, dev, saddr, daddr, prio,
 			     ttl, src_port, dst_port,
 			     !!(vxflags & VXLAN_F_UDP_ZERO_CSUM6_TX));
 	return 0;
@@ -1758,7 +1759,7 @@ static int vxlan6_xmit_skb(struct dst_entry *dst, struct sk_buff *skb,
 }
 #endif
 
-int vxlan_xmit_skb(struct rtable *rt, struct sk_buff *skb,
+int vxlan_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
 		   __be32 src, __be32 dst, __u8 tos, __u8 ttl, __be16 df,
 		   __be16 src_port, __be16 dst_port,
 		   struct vxlan_metadata *md, bool xnet, u32 vxflags)
@@ -1827,7 +1828,7 @@ int vxlan_xmit_skb(struct rtable *rt, struct sk_buff *skb,
 
 	skb_set_inner_protocol(skb, htons(ETH_P_TEB));
 
-	return udp_tunnel_xmit_skb(rt, skb, src, dst, tos,
+	return udp_tunnel_xmit_skb(rt, sk, skb, src, dst, tos,
 				   ttl, df, src_port, dst_port, xnet,
 				   !(vxflags & VXLAN_F_UDP_CSUM));
 }
@@ -1882,6 +1883,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 			   struct vxlan_rdst *rdst, bool did_rsc)
 {
 	struct vxlan_dev *vxlan = netdev_priv(dev);
+	struct sock *sk = vxlan->vn_sock->sock->sk;
 	struct rtable *rt = NULL;
 	const struct iphdr *old_iph;
 	struct flowi4 fl4;
@@ -1961,7 +1963,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 		md.vni = htonl(vni << 8);
 		md.gbp = skb->mark;
 
-		err = vxlan_xmit_skb(rt, skb, fl4.saddr,
+		err = vxlan_xmit_skb(rt, sk, skb, fl4.saddr,
 				     dst->sin.sin_addr.s_addr, tos, ttl, df,
 				     src_port, dst_port, &md,
 				     !net_eq(vxlan->net, dev_net(vxlan->dev)),
@@ -2021,7 +2023,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 		md.vni = htonl(vni << 8);
 		md.gbp = skb->mark;
 
-		err = vxlan6_xmit_skb(ndst, skb, dev, &fl6.saddr, &fl6.daddr,
+		err = vxlan6_xmit_skb(ndst, sk, skb, dev, &fl6.saddr, &fl6.daddr,
 				      0, ttl, src_port, dst_port, &md,
 				      !net_eq(vxlan->net, dev_net(vxlan->dev)),
 				      vxlan->flags);

include/net/ip6_tunnel.h

@@ -73,13 +73,14 @@ __u32 ip6_tnl_get_cap(struct ip6_tnl *t, const struct in6_addr *laddr,
 struct net *ip6_tnl_get_link_net(const struct net_device *dev);
 int ip6_tnl_get_iflink(const struct net_device *dev);
 
-static inline void ip6tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
+static inline void ip6tunnel_xmit(struct sock *sk, struct sk_buff *skb,
+				  struct net_device *dev)
 {
 	struct net_device_stats *stats = &dev->stats;
 	int pkt_len, err;
 
 	pkt_len = skb->len;
-	err = ip6_local_out(skb);
+	err = ip6_local_out_sk(sk, skb);
 
 	if (net_xmit_eval(err) == 0) {
 		struct pcpu_sw_netstats *tstats = this_cpu_ptr(dev->tstats);

include/net/ipv6.h

@@ -827,6 +827,7 @@ int ip6_input(struct sk_buff *skb);
 int ip6_mc_input(struct sk_buff *skb);
 
 int __ip6_local_out(struct sk_buff *skb);
+int ip6_local_out_sk(struct sock *sk, struct sk_buff *skb);
 int ip6_local_out(struct sk_buff *skb);
 
 /*

include/net/udp_tunnel.h

@@ -77,13 +77,14 @@ void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
 			   struct udp_tunnel_sock_cfg *sock_cfg);
 
 /* Transmit the skb using UDP encapsulation. */
-int udp_tunnel_xmit_skb(struct rtable *rt, struct sk_buff *skb,
+int udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
 			__be32 src, __be32 dst, __u8 tos, __u8 ttl,
 			__be16 df, __be16 src_port, __be16 dst_port,
 			bool xnet, bool nocheck);
 
 #if IS_ENABLED(CONFIG_IPV6)
-int udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sk_buff *skb,
+int udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
+			 struct sk_buff *skb,
 			 struct net_device *dev, struct in6_addr *saddr,
 			 struct in6_addr *daddr,
 			 __u8 prio, __u8 ttl, __be16 src_port,

include/net/vxlan.h

@@ -145,7 +145,7 @@ struct vxlan_sock *vxlan_sock_add(struct net *net, __be16 port,
 
 void vxlan_sock_release(struct vxlan_sock *vs);
 
-int vxlan_xmit_skb(struct rtable *rt, struct sk_buff *skb,
+int vxlan_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
 		   __be32 src, __be32 dst, __u8 tos, __u8 ttl, __be16 df,
 		   __be16 src_port, __be16 dst_port, struct vxlan_metadata *md,
 		   bool xnet, u32 vxflags);

net/ipv4/geneve.c

@@ -136,7 +136,7 @@ int geneve_xmit_skb(struct geneve_sock *gs, struct rtable *rt,
 
 	skb_set_inner_protocol(skb, htons(ETH_P_TEB));
 
-	return udp_tunnel_xmit_skb(rt, skb, src, dst,
+	return udp_tunnel_xmit_skb(rt, gs->sock->sk, skb, src, dst,
 				   tos, ttl, df, src_port, dst_port, xnet,
 				   !csum);
 }

net/ipv4/ip_tunnel.c

@@ -782,7 +782,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 		return;
 	}
 
-	err = iptunnel_xmit(skb->sk, rt, skb, fl4.saddr, fl4.daddr, protocol,
+	err = iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol,
 			    tos, ttl, df, !net_eq(tunnel->net, dev_net(dev)));
 	iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 

net/ipv4/udp_tunnel.c

@@ -75,7 +75,7 @@ void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
 }
 EXPORT_SYMBOL_GPL(setup_udp_tunnel_sock);
 
-int udp_tunnel_xmit_skb(struct rtable *rt, struct sk_buff *skb,
+int udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
 			__be32 src, __be32 dst, __u8 tos, __u8 ttl,
 			__be16 df, __be16 src_port, __be16 dst_port,
 			bool xnet, bool nocheck)
@@ -92,7 +92,7 @@ int udp_tunnel_xmit_skb(struct rtable *rt, struct sk_buff *skb,
 
 	udp_set_csum(nocheck, skb, src, dst, skb->len);
 
-	return iptunnel_xmit(skb->sk, rt, skb, src, dst, IPPROTO_UDP,
+	return iptunnel_xmit(sk, rt, skb, src, dst, IPPROTO_UDP,
 			     tos, ttl, df, xnet);
 }
 EXPORT_SYMBOL_GPL(udp_tunnel_xmit_skb);

net/ipv6/ip6_gre.c

@@ -760,7 +760,7 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
 
 	skb_set_inner_protocol(skb, protocol);
 
-	ip6tunnel_xmit(skb, dev);
+	ip6tunnel_xmit(NULL, skb, dev);
 	if (ndst)
 		ip6_tnl_dst_store(tunnel, ndst);
 	return 0;

net/ipv6/ip6_tunnel.c

@@ -1100,7 +1100,7 @@ static int ip6_tnl_xmit2(struct sk_buff *skb,
 	ipv6h->nexthdr = proto;
 	ipv6h->saddr = fl6->saddr;
 	ipv6h->daddr = fl6->daddr;
-	ip6tunnel_xmit(skb, dev);
+	ip6tunnel_xmit(NULL, skb, dev);
 	if (ndst)
 		ip6_tnl_dst_store(t, ndst);
 	return 0;

net/ipv6/ip6_udp_tunnel.c

@@ -62,7 +62,8 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
 }
 EXPORT_SYMBOL_GPL(udp_sock_create6);
 
-int udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sk_buff *skb,
+int udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
+			 struct sk_buff *skb,
 			 struct net_device *dev, struct in6_addr *saddr,
 			 struct in6_addr *daddr,
 			 __u8 prio, __u8 ttl, __be16 src_port,
@@ -97,7 +98,7 @@ int udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sk_buff *skb,
 	ip6h->daddr	  = *daddr;
 	ip6h->saddr	  = *saddr;
 
-	ip6tunnel_xmit(skb, dev);
+	ip6tunnel_xmit(sk, skb, dev);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(udp_tunnel6_xmit_skb);

net/ipv6/output_core.c

@@ -136,7 +136,7 @@ int ip6_dst_hoplimit(struct dst_entry *dst)
 EXPORT_SYMBOL(ip6_dst_hoplimit);
 #endif
 
-int __ip6_local_out(struct sk_buff *skb)
+static int __ip6_local_out_sk(struct sock *sk, struct sk_buff *skb)
 {
 	int len;
 
@@ -146,19 +146,30 @@ int __ip6_local_out(struct sk_buff *skb)
 	ipv6_hdr(skb)->payload_len = htons(len);
 	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
 
-	return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb->sk, skb,
+	return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb,
 		       NULL, skb_dst(skb)->dev, dst_output_sk);
 }
+
+int __ip6_local_out(struct sk_buff *skb)
+{
+	return __ip6_local_out_sk(skb->sk, skb);
+}
 EXPORT_SYMBOL_GPL(__ip6_local_out);
 
-int ip6_local_out(struct sk_buff *skb)
+int ip6_local_out_sk(struct sock *sk, struct sk_buff *skb)
 {
 	int err;
 
-	err = __ip6_local_out(skb);
+	err = __ip6_local_out_sk(sk, skb);
 	if (likely(err == 1))
-		err = dst_output(skb);
+		err = dst_output_sk(sk, skb);
 
 	return err;
 }
+EXPORT_SYMBOL_GPL(ip6_local_out_sk);
+
+int ip6_local_out(struct sk_buff *skb)
+{
+	return ip6_local_out_sk(skb->sk, skb);
+}
 EXPORT_SYMBOL_GPL(ip6_local_out);

net/openvswitch/vport-vxlan.c

@@ -222,7 +222,8 @@ static int vxlan_tnl_send(struct vport *vport, struct sk_buff *skb)
 {
 	struct net *net = ovs_dp_get_net(vport->dp);
 	struct vxlan_port *vxlan_port = vxlan_vport(vport);
-	__be16 dst_port = inet_sk(vxlan_port->vs->sock->sk)->inet_sport;
+	struct sock *sk = vxlan_port->vs->sock->sk;
+	__be16 dst_port = inet_sk(sk)->inet_sport;
 	const struct ovs_key_ipv4_tunnel *tun_key;
 	struct vxlan_metadata md = {0};
 	struct rtable *rt;
@@ -255,7 +256,7 @@ static int vxlan_tnl_send(struct vport *vport, struct sk_buff *skb)
 	vxflags = vxlan_port->exts |
 		      (tun_key->tun_flags & TUNNEL_CSUM ? VXLAN_F_UDP_CSUM : 0);
 
-	err = vxlan_xmit_skb(rt, skb, fl.saddr, tun_key->ipv4_dst,
+	err = vxlan_xmit_skb(rt, sk, skb, fl.saddr, tun_key->ipv4_dst,
 			     tun_key->ipv4_tos, tun_key->ipv4_ttl, df,
 			     src_port, dst_port,
 			     &md, false, vxflags);

net/tipc/udp_media.c

@@ -176,7 +176,8 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
 			goto tx_error;
 		}
 		ttl = ip4_dst_hoplimit(&rt->dst);
-		err = udp_tunnel_xmit_skb(rt, clone, src->ipv4.s_addr,
+		err = udp_tunnel_xmit_skb(rt, ub->ubsock->sk, clone,
+					  src->ipv4.s_addr,
 					  dst->ipv4.s_addr, 0, ttl, 0,
 					  src->udp_port, dst->udp_port,
 					  false, true);
@@ -197,7 +198,8 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
 		if (err)
 			goto tx_error;
 		ttl = ip6_dst_hoplimit(ndst);
-		err = udp_tunnel6_xmit_skb(ndst, clone, ndst->dev, &src->ipv6,
+		err = udp_tunnel6_xmit_skb(ndst, ub->ubsock->sk, clone,
+					   ndst->dev, &src->ipv6,
 					   &dst->ipv6, 0, ttl, src->udp_port,
 					   dst->udp_port, false);
 #endif