ipmr: support IP_PKTINFO on cache report IGMP msg

[ Upstream commit bb7403655b3c3eb245d0ee330047cd3e20b3c4af ]

In order to support IP_PKTINFO on those packets, we need to call
ipv4_pktinfo_prepare.

When sending mrouted/pimd daemons a cache report IGMP msg, it is
unnecessary to set dst on the newly created skb.
It used to be necessary on older versions until
commit d826eb14ecef ("ipv4: PKTINFO doesnt need dst reference") which
changed the way IP_PKTINFO struct is been retrieved.

Changes from v1:
1. Undo changes in ipv4_pktinfo_prepare function. use it directly
   and copy the control block.

Fixes: d826eb14ecef ("ipv4: PKTINFO doesnt need dst reference")
Signed-off-by: Leone Fernando <leone4fernando@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 9e222a5..0063a23 100644 (file)
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1025,6 +1025,10 @@ static int ipmr_cache_report(const struct mr_table *mrt,
        struct sk_buff *skb;
        int ret;
 
+       mroute_sk = rcu_dereference(mrt->mroute_sk);
+       if (!mroute_sk)
+               return -EINVAL;
+
        if (assert == IGMPMSG_WHOLEPKT || assert == IGMPMSG_WRVIFWHOLE)
                skb = skb_realloc_headroom(pkt, sizeof(struct iphdr));
        else
@@ -1069,7 +1073,8 @@ static int ipmr_cache_report(const struct mr_table *mrt,
                msg = (struct igmpmsg *)skb_network_header(skb);
                msg->im_vif = vifi;
                msg->im_vif_hi = vifi >> 8;
-               skb_dst_set(skb, dst_clone(skb_dst(pkt)));
+               ipv4_pktinfo_prepare(mroute_sk, pkt);
+               memcpy(skb->cb, pkt->cb, sizeof(skb->cb));
                /* Add our header */
                igmp = skb_put(skb, sizeof(struct igmphdr));
                igmp->type = assert;
@@ -1079,12 +1084,6 @@ static int ipmr_cache_report(const struct mr_table *mrt,
                skb->transport_header = skb->network_header;
        }
 
-       mroute_sk = rcu_dereference(mrt->mroute_sk);
-       if (!mroute_sk) {
-               kfree_skb(skb);
-               return -EINVAL;
-       }
-
        igmpmsg_netlink_event(mrt, skb);
 
        /* Deliver to mrouted */