diff options
Diffstat (limited to 'target/linux/generic')
| -rw-r--r-- | target/linux/generic/patches-4.4/646-bridge_fix_ipv6_mc_snooping_if_bridge_has_no_ipv6_address.patch | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/target/linux/generic/patches-4.4/646-bridge_fix_ipv6_mc_snooping_if_bridge_has_no_ipv6_address.patch b/target/linux/generic/patches-4.4/646-bridge_fix_ipv6_mc_snooping_if_bridge_has_no_ipv6_address.patch new file mode 100644 index 0000000000..4388cda6ef --- /dev/null +++ b/target/linux/generic/patches-4.4/646-bridge_fix_ipv6_mc_snooping_if_bridge_has_no_ipv6_address.patch @@ -0,0 +1,113 @@ +From: daniel <daniel@dd-wrt.com> +Date: Fri, 24 Jun 2016 12:35:18 +0200 +Subject: [PATCH] Bridge: Fix ipv6 mc snooping if bridge has no ipv6 address + +The bridge is falsly dropping ipv6 mulitcast packets if there is: + 1. No ipv6 address assigned on the brigde. + 2. No external mld querier present. + 3. The internal querier enabled. + +When the bridge fails to build mld queries, because it has no +ipv6 address, it slilently returns, but keeps the local querier enabled. +This specific case causes confusing packet loss. + +Ipv6 multicast snooping can only work if: + a) An external querier is present + OR + b) The bridge has an ipv6 address an is capable of sending own queries + +Otherwise it has to forward/flood the ipv6 multicast traffic, +because snooping cannot work. + +This patch fixes the issue by adding a flag to the bridge struct that +indicates that there is currently no ipv6 address assinged to the bridge +and returns a false state for the local querier in +__br_multicast_querier_exists(). + +Special thanks to Linus Lüssing. + +Fixes: d1d81d4c3dd8 ("bridge: check return value of ipv6_dev_get_saddr()") +Signed-off-by: Daniel Danzberger <daniel@dd-wrt.com> +Acked-by: Linus Lüssing <linus.luessing@c0d3.blue> +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + net/bridge/br_multicast.c | 4 ++++ + net/bridge/br_private.h | 23 +++++++++++++++++++---- + 2 files changed, 23 insertions(+), 4 deletions(-) + +diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c +index c8c2a8a..d063a10 100644 +--- a/net/bridge/br_multicast.c ++++ b/net/bridge/br_multicast.c +@@ -465,8 +465,11 @@ static struct sk_buff *br_ip6_multicast_alloc_query(struct net_bridge *br, + if (ipv6_dev_get_saddr(dev_net(br->dev), br->dev, &ip6h->daddr, 0, + &ip6h->saddr)) { + kfree_skb(skb); ++ br->has_ipv6_addr = 0; + return NULL; + } ++ ++ br->has_ipv6_addr = 1; + ipv6_eth_mc_map(&ip6h->daddr, eth->h_dest); + + hopopt = (u8 *)(ip6h + 1); +@@ -1768,6 +1771,7 @@ void br_multicast_init(struct net_bridge *br) + br->ip6_other_query.delay_time = 0; + br->ip6_querier.port = NULL; + #endif ++ br->has_ipv6_addr = 1; + + spin_lock_init(&br->multicast_lock); + setup_timer(&br->multicast_router_timer, +diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h +index e24abfd..3dd7e2c 100644 +--- a/net/bridge/br_private.h ++++ b/net/bridge/br_private.h +@@ -303,6 +303,7 @@ struct net_bridge + u8 multicast_disabled:1; + u8 multicast_querier:1; + u8 multicast_query_use_ifaddr:1; ++ u8 has_ipv6_addr:1; + + u32 hash_elasticity; + u32 hash_max; +@@ -577,10 +578,22 @@ static inline bool br_multicast_is_router(struct net_bridge *br) + + static inline bool + __br_multicast_querier_exists(struct net_bridge *br, +- struct bridge_mcast_other_query *querier) ++ struct bridge_mcast_other_query *querier, ++ const bool is_ipv6) + { ++ bool own_querier_enabled; ++ ++ if (br->multicast_querier) { ++ if (is_ipv6 && !br->has_ipv6_addr) ++ own_querier_enabled = false; ++ else ++ own_querier_enabled = true; ++ } else { ++ own_querier_enabled = false; ++ } ++ + return time_is_before_jiffies(querier->delay_time) && +- (br->multicast_querier || timer_pending(&querier->timer)); ++ (own_querier_enabled || timer_pending(&querier->timer)); + } + + static inline bool br_multicast_querier_exists(struct net_bridge *br, +@@ -588,10 +601,12 @@ static inline bool br_multicast_querier_exists(struct net_bridge *br, + { + switch (eth->h_proto) { + case (htons(ETH_P_IP)): +- return __br_multicast_querier_exists(br, &br->ip4_other_query); ++ return __br_multicast_querier_exists(br, ++ &br->ip4_other_query, false); + #if IS_ENABLED(CONFIG_IPV6) + case (htons(ETH_P_IPV6)): +- return __br_multicast_querier_exists(br, &br->ip6_other_query); ++ return __br_multicast_querier_exists(br, ++ &br->ip6_other_query, true); + #endif + default: + return false; |