ipv4: Pass original device to ip_rcv_finish_core [Linux 5.0]

This Linux kernel change "ipv4: Pass original device to ip_rcv_finish_core" is included in the Linux 5.0 release. This change is authored by David Ahern <dsahern [at] gmail.com> on Mon Feb 25 13:55:48 2019 -0800. The commit for this change in Linux stable tree is a1fd1ad (patch).

ipv4: Pass original device to ip_rcv_finish_core

ip_route_input_rcu expects the original ingress device (e.g., for
proper multicast handling). The skb->dev can be changed by l3mdev_ip_rcv,
so dev needs to be saved prior to calling it. This was the behavior prior
to the listify changes.

Fixes: 5fa12739a53d0 ("net: ipv4: listify ip_rcv_finish")
Cc: Edward Cree <[email protected]>
Signed-off-by: David Ahern <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

There are 9 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 net/ipv4/ip_input.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 51d8efb..1f4737b 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -307,11 +307,10 @@ static inline bool ip_rcv_options(struct sk_buff *skb)
 }

 static int ip_rcv_finish_core(struct net *net, struct sock *sk,
-                 struct sk_buff *skb)
+                 struct sk_buff *skb, struct net_device *dev)
 {
    const struct iphdr *iph = ip_hdr(skb);
    int (*edemux)(struct sk_buff *skb);
-   struct net_device *dev = skb->dev;
    struct rtable *rt;
    int err;

@@ -400,6 +399,7 @@ static int ip_rcv_finish_core(struct net *net, struct sock *sk,

 static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
+   struct net_device *dev = skb->dev;
    int ret;

    /* if ingress device is enslaved to an L3 master device pass the
@@ -409,7 +409,7 @@ static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
    if (!skb)
        return NET_RX_SUCCESS;

-   ret = ip_rcv_finish_core(net, sk, skb);
+   ret = ip_rcv_finish_core(net, sk, skb, dev);
    if (ret != NET_RX_DROP)
        ret = dst_input(skb);
    return ret;
@@ -545,6 +545,7 @@ static void ip_list_rcv_finish(struct net *net, struct sock *sk,

    INIT_LIST_HEAD(&sublist);
    list_for_each_entry_safe(skb, next, head, list) {
+       struct net_device *dev = skb->dev;
        struct dst_entry *dst;

        skb_list_del_init(skb);
@@ -554,7 +555,7 @@ static void ip_list_rcv_finish(struct net *net, struct sock *sk,
        skb = l3mdev_ip_rcv(skb);
        if (!skb)
            continue;
-       if (ip_rcv_finish_core(net, sk, skb) == NET_RX_DROP)
+       if (ip_rcv_finish_core(net, sk, skb, dev) == NET_RX_DROP)
            continue;

        dst = skb_dst(skb);

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