2023-12-13 16:28:34

by Leone Fernando

Subject: [PATCH net-next v2] ipmr: support IP_PKTINFO on cache report IGMP msg

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 <[email protected]>
---
net/ipv4/ipmr.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 9e222a57bc2b..0063a237253b 100644
--- 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 */
--
2.34.1

2023-12-14 13:17:40

by Eric Dumazet

Subject: Re: [PATCH net-next v2] ipmr: support IP_PKTINFO on cache report IGMP msg

On Wed, Dec 13, 2023 at 5:28 PM Leone Fernando <[email protected]> wrote:
>
> 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 <[email protected]>

Reviewed-by: Eric Dumazet <[email protected]>

2023-12-19 00:00:33

by Jakub Kicinski

Subject: Re: [PATCH net-next v2] ipmr: support IP_PKTINFO on cache report IGMP msg

On Wed, 13 Dec 2023 17:19:35 +0100 Leone Fernando wrote:
> 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 <[email protected]>

Applied to net-next, thanks!