+ Bridge maintainers, Linus
On Tue, Aug 13, 2019 at 03:18:04PM +0100, Patrick Ruddy wrote:
> At present only all-nodes IPv6 multicast packets are accepted by
> a bridge interface that is not in multicast router mode. Since
> other protocols can be running in the absense of multicast
> forwarding e.g. OSPFv3 IPv6 ND. Change the test to allow
> all of the FFx2::/16 range to be accepted when not in multicast
> router mode. This aligns the code with IPv4 link-local reception
> and RFC4291
Can you please quote the relevant part from RFC 4291?
>
> Signed-off-by: Patrick Ruddy <pru...@vyatta.att-mail.com>
> ---
> include/net/addrconf.h | 15 +++++++++++++++
> net/bridge/br_multicast.c | 2 +-
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/include/net/addrconf.h b/include/net/addrconf.h
> index becdad576859..05b42867e969 100644
> --- a/include/net/addrconf.h
> +++ b/include/net/addrconf.h
> @@ -434,6 +434,21 @@ static inline void addrconf_addr_solict_mult(const
> struct in6_addr *addr,
> htonl(0xFF000000) | addr->s6_addr32[3]);
> }
>
> +/*
> + * link local multicast address range ffx2::/16 rfc4291
> + */
> +static inline bool ipv6_addr_is_ll_mcast(const struct in6_addr *addr)
> +{
> +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
> + __be64 *p = (__be64 *)addr;
> + return ((p[0] & cpu_to_be64(0xff0f000000000000UL))
> + ^ cpu_to_be64(0xff02000000000000UL)) == 0UL;
> +#else
> + return ((addr->s6_addr32[0] & htonl(0xff0f0000)) ^
> + htonl(0xff020000)) == 0;
> +#endif
> +}
> +
> static inline bool ipv6_addr_is_ll_all_nodes(const struct in6_addr *addr)
> {
> #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
> diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
> index 9b379e110129..ed3957381fa2 100644
> --- a/net/bridge/br_multicast.c
> +++ b/net/bridge/br_multicast.c
> @@ -1664,7 +1664,7 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
> err = ipv6_mc_check_mld(skb);
>
> if (err == -ENOMSG) {
> - if (!ipv6_addr_is_ll_all_nodes(&ipv6_hdr(skb)->daddr))
> + if (!ipv6_addr_is_ll_mcast(&ipv6_hdr(skb)->daddr))
> BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
IIUC, you want IPv6 link-local packets to be locally received, but this
also changes how these packets are flooded. RFC 4541 says that packets
addressed to the all hosts address are a special case and should be
forwarded to all ports:
"In IPv6, the data forwarding rules are more straight forward because MLD is
mandated for addresses with scope 2 (link-scope) or greater. The only exception
is the address FF02::1 which is the all hosts link-scope address for which MLD
messages are never sent. Packets with the all hosts link-scope address should
be forwarded on all ports."
Maybe you want something like:
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 09b1dd8cd853..9f312a73f61c 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -132,7 +132,8 @@ 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(br, eth_hdr(skb))) {
if ((mdst && mdst->host_joined) ||
- br_multicast_is_router(br)) {
+ br_multicast_is_router(br) ||
+ BR_INPUT_SKB_CB_LOCAL_RECEIVE(skb)) {
local_rcv = true;
br->dev->stats.multicast++;
}
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 9b379e110129..f03cecf6174e 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1667,6 +1667,9 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
if (!ipv6_addr_is_ll_all_nodes(&ipv6_hdr(skb)->daddr))
BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
+ if (ipv6_addr_is_ll_mcast(&ipv6_hdr(skb)->daddr))
+ BR_INPUT_SKB_CB(skb)->local_receive = 1;
+
if (ipv6_addr_is_all_snoopers(&ipv6_hdr(skb)->daddr)) {
err = br_ip6_multicast_mrd_rcv(br, port, skb);
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index b7a4942ff1b3..d76394ca4059 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -426,6 +426,7 @@ struct br_input_skb_cb {
#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
u8 igmp;
u8 mrouters_only:1;
+ u8 local_receive:1;
#endif
u8 proxyarp_replied:1;
u8 src_port_isolated:1;
@@ -445,8 +446,10 @@ struct br_input_skb_cb {
#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
# define BR_INPUT_SKB_CB_MROUTERS_ONLY(__skb)
(BR_INPUT_SKB_CB(__skb)->mrouters_only)
+# define BR_INPUT_SKB_CB_LOCAL_RECEIVE(__skb)
(BR_INPUT_SKB_CB(__skb)->local_receive)
#else
# define BR_INPUT_SKB_CB_MROUTERS_ONLY(__skb) (0)
+# define BR_INPUT_SKB_CB_LOCAL_RECEIVE(__skb) (0)
#endif
#define br_printk(level, br, format, args...) \
