diff mbox series

[net-next,v3] net: bridge: locally receive all multicast packets if IFF_ALLMULTI is set

Message ID OSZPR01MB8434308370ACAFA90A22980798B32@OSZPR01MB8434.jpnprd01.prod.outlook.com (mailing list archive)
State Accepted
Commit a496d2f0fd612ab9e10700afe00dc9267bad788b
Delegated to: Netdev Maintainers
Headers show
Series [net-next,v3] net: bridge: locally receive all multicast packets if IFF_ALLMULTI is set | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1 this patch: 1
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 2 this patch: 2
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 2 this patch: 2
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 9 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2025-04-15--21-00 (tests: 914)

Commit Message

Shengyu Qu April 14, 2025, 10:56 a.m. UTC
If multicast snooping is enabled, multicast packets may not always end up
on the local bridge interface, if the host is not a member of the multicast
group. Similar to how IFF_PROMISC allows all packets to be received
locally, let IFF_ALLMULTI allow all multicast packets to be received.

OpenWrt uses a user space daemon for DHCPv6/RA/NDP handling, and in relay
mode it sets the ALLMULTI flag in order to receive all relevant queries on
the network.

This works for normal network interfaces and non-snooping bridges, but not
snooping bridges (unless multicast routing is enabled).

Reported-by: Felix Fietkau <nbd@nbd.name>
Closes:https://github.com/openwrt/openwrt/issues/15857#issuecomment-2662851243
Signed-off-by: Shengyu Qu <wiagn233@outlook.com>
---
Changes since v1:
 - Move to net-next
 - Changed code according to Nikolay's advice

Changes since v2:
 - Fix alignment
 - Remove redundant parenthesis
 - Add more infomation in commit message
---
 net/bridge/br_input.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Ido Schimmel April 15, 2025, 6:10 a.m. UTC | #1
On Mon, Apr 14, 2025 at 06:56:01PM +0800, Shengyu Qu wrote:
> If multicast snooping is enabled, multicast packets may not always end up
> on the local bridge interface, if the host is not a member of the multicast
> group. Similar to how IFF_PROMISC allows all packets to be received
> locally, let IFF_ALLMULTI allow all multicast packets to be received.
> 
> OpenWrt uses a user space daemon for DHCPv6/RA/NDP handling, and in relay
> mode it sets the ALLMULTI flag in order to receive all relevant queries on
> the network.
> 
> This works for normal network interfaces and non-snooping bridges, but not
> snooping bridges (unless multicast routing is enabled).
> 
> Reported-by: Felix Fietkau <nbd@nbd.name>
> Closes:https://github.com/openwrt/openwrt/issues/15857#issuecomment-2662851243
> Signed-off-by: Shengyu Qu <wiagn233@outlook.com>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Nikolay Aleksandrov April 15, 2025, 9:39 a.m. UTC | #2
On 4/14/25 13:56, Shengyu Qu wrote:
> If multicast snooping is enabled, multicast packets may not always end up
> on the local bridge interface, if the host is not a member of the multicast
> group. Similar to how IFF_PROMISC allows all packets to be received
> locally, let IFF_ALLMULTI allow all multicast packets to be received.
> 
> OpenWrt uses a user space daemon for DHCPv6/RA/NDP handling, and in relay
> mode it sets the ALLMULTI flag in order to receive all relevant queries on
> the network.
> 
> This works for normal network interfaces and non-snooping bridges, but not
> snooping bridges (unless multicast routing is enabled).
> 
> Reported-by: Felix Fietkau <nbd@nbd.name>
> Closes:https://github.com/openwrt/openwrt/issues/15857#issuecomment-2662851243
> Signed-off-by: Shengyu Qu <wiagn233@outlook.com>
> ---
> Changes since v1:
>  - Move to net-next
>  - Changed code according to Nikolay's advice
> 
> Changes since v2:
>  - Fix alignment
>  - Remove redundant parenthesis
>  - Add more infomation in commit message
> ---
>  net/bridge/br_input.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> index 232133a0fd21..5f6ac9bf1527 100644
> --- a/net/bridge/br_input.c
> +++ b/net/bridge/br_input.c
> @@ -189,7 +189,8 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
>  		if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
>  		    br_multicast_querier_exists(brmctx, eth_hdr(skb), mdst)) {
>  			if ((mdst && mdst->host_joined) ||
> -			    br_multicast_is_router(brmctx, skb)) {
> +			    br_multicast_is_router(brmctx, skb) ||
> +			    br->dev->flags & IFF_ALLMULTI) {
>  				local_rcv = true;
>  				DEV_STATS_INC(br->dev, multicast);
>  			}

Thanks,
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
patchwork-bot+netdevbpf@kernel.org April 16, 2025, 1 a.m. UTC | #3
Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 14 Apr 2025 18:56:01 +0800 you wrote:
> If multicast snooping is enabled, multicast packets may not always end up
> on the local bridge interface, if the host is not a member of the multicast
> group. Similar to how IFF_PROMISC allows all packets to be received
> locally, let IFF_ALLMULTI allow all multicast packets to be received.
> 
> OpenWrt uses a user space daemon for DHCPv6/RA/NDP handling, and in relay
> mode it sets the ALLMULTI flag in order to receive all relevant queries on
> the network.
> 
> [...]

Here is the summary with links:
  - [net-next,v3] net: bridge: locally receive all multicast packets if IFF_ALLMULTI is set
    https://git.kernel.org/netdev/net-next/c/a496d2f0fd61

You are awesome, thank you!
diff mbox series

Patch

diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 232133a0fd21..5f6ac9bf1527 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -189,7 +189,8 @@  int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
 		if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
 		    br_multicast_querier_exists(brmctx, eth_hdr(skb), mdst)) {
 			if ((mdst && mdst->host_joined) ||
-			    br_multicast_is_router(brmctx, skb)) {
+			    br_multicast_is_router(brmctx, skb) ||
+			    br->dev->flags & IFF_ALLMULTI) {
 				local_rcv = true;
 				DEV_STATS_INC(br->dev, multicast);
 			}