Merge branch 'vrf-pktinfo'

David Ahern says:

====================
net: vrf: Fixup PKTINFO to return enslaved device index

Applications such as OSPF and BFD need the original ingress device not
the VRF device; the latter can be derived from the former. To that end
move the packet intercept from an rx handler that is invoked by
__netif_receive_skb_core to the ipv4 and ipv6 receive processing.

IPv6 already saves the skb_iif to the control buffer in ipv6_rcv. Since
the skb->dev has not been switched the cb has the enslaved device. Make
the same happen for IPv4 by adding the skb_iif to inet_skb_parm and set
it in ipv4 code after clearing the skb control buffer similar to IPv6.
From there the pktinfo can just pull it from cb with the PKTINFO_SKB_CB
cast.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 23 insertions, 2 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index c7490339315c..12436d1312ca 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1850,7 +1850,7 @@ static inline bool skb_loop_sk(struct packet_type *ptype, struct sk_buff *skb)
  *	taps currently in use.
  */
 
-static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
+void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct packet_type *ptype;
 	struct sk_buff *skb2 = NULL;
@@ -1907,6 +1907,7 @@ out_unlock:
 		pt_prev->func(skb2, skb->dev, pt_prev, skb->dev);
 	rcu_read_unlock();
 }
+EXPORT_SYMBOL_GPL(dev_queue_xmit_nit);
 
 /**
  * netif_setup_tc - Handle tc mappings on real_num_tx_queues change
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 751c0658e194..4b351af3e67b 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -313,6 +313,13 @@ static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 	const struct iphdr *iph = ip_hdr(skb);
 	struct rtable *rt;
 
+	/* if ingress device is enslaved to an L3 master device pass the
+	 * skb to its handler for processing
+	 */
+	skb = l3mdev_ip_rcv(skb);
+	if (!skb)
+		return NET_RX_SUCCESS;
+
 	if (net->ipv4.sysctl_ip_early_demux &&
 	    !skb_dst(skb) &&
 	    !skb->sk &&
@@ -471,6 +478,7 @@ int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
 
 	/* Remove any debris in the socket control block */
 	memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
+	IPCB(skb)->iif = skb->skb_iif;
 
 	/* Must drop socket now because of tproxy. */
 	skb_orphan(skb);
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index bdb222c0c6a2..5805762d7fc7 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1193,7 +1193,12 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb)
 		       ipv6_sk_rxinfo(sk);
 
 	if (prepare && skb_rtable(skb)) {
-		pktinfo->ipi_ifindex = inet_iif(skb);
+		/* skb->cb is overloaded: prior to this point it is IP{6}CB
+		 * which has interface index (iif) as the first member of the
+		 * underlying inet{6}_skb_parm struct. This code then overlays
+		 * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
+		 * element so the iif is picked up from the prior IPCB
+		 */
 		pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
 	} else {
 		pktinfo->ipi_ifindex = 0;
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 6ed56012005d..f185cbcda114 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -49,6 +49,13 @@
 
 int ip6_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
+	/* if ingress device is enslaved to an L3 master device pass the
+	 * skb to its handler for processing
+	 */
+	skb = l3mdev_ip6_rcv(skb);
+	if (!skb)
+		return NET_RX_SUCCESS;
+
 	if (net->ipv4.sysctl_ip_early_demux && !skb_dst(skb) && skb->sk == NULL) {
 		const struct inet6_protocol *ipprot;