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openwrtv4/target/linux/generic/patches-4.1/645-bridge_multicast_to_unicast.patch
Felix Fietkau 2416e506f5 kernel: bridge, multicast-to-unicast: fix echoes on STA 
Currently, multicast packets from an STA are sent to any according
multicast listener directly through the bridge multicast-to-unicast
feature. Unfortunately, so far this includes the originating STA, too,
resulting in multicast packets being echo'ed back to the originating STA
if it itself is a multicast listener for that group.

This behaviour breaks IPv6 duplicate address detection: An IPv6 Neighbor
Solicitation for IPv6 Duplicate Address Detection is being echo'ed back,
resulting in the host falsely detecting an address collision, which
makes the node unable to claim an IPv6 address and use IPv6 in general.

Mac80211 unfortunately only prevents the echoes for us for multicast
frames. For the multicast frames cast to a unicast destination we'll
need to take care of excluding the originator ourselves.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>

SVN-Revision: 46765
2015-09-02 09:23:59 +00:00

392 lines
11 KiB
Diff
Raw Blame History

--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -46,6 +46,7 @@ struct br_ip_list {
#define BR_LEARNING_SYNC BIT(9)
#define BR_PROXYARP_WIFI BIT(10)
#define BR_ISOLATE_MODE BIT(11)
+#define BR_MULTICAST_TO_UCAST BIT(12)
extern void brioctl_set(int (*ioctl_hook)(struct net *, unsigned int, void __user *));
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -635,7 +635,8 @@ struct net_bridge_port_group *br_multica
struct net_bridge_port *port,
struct br_ip *group,
struct net_bridge_port_group __rcu *next,
- unsigned char state)
+ unsigned char state,
+ const unsigned char *src)
{
struct net_bridge_port_group *p;
@@ -650,12 +651,33 @@ struct net_bridge_port_group *br_multica
hlist_add_head(&p->mglist, &port->mglist);
setup_timer(&p->timer, br_multicast_port_group_expired,
(unsigned long)p);
+ if ((port->flags & BR_MULTICAST_TO_UCAST) && src) {
+ memcpy(p->eth_addr, src, ETH_ALEN);
+ p->unicast = true;
+ }
return p;
}
+static bool br_port_group_equal(struct net_bridge_port_group *p,
+ struct net_bridge_port *port,
+ const unsigned char *src)
+{
+ if (p->port != port)
+ return false;
+
+ if (!p->unicast)
+ return true;
+
+ if (!src)
+ return false;
+
+ return ether_addr_equal(src, p->eth_addr);
+}
+
static int br_multicast_add_group(struct net_bridge *br,
struct net_bridge_port *port,
- struct br_ip *group)
+ struct br_ip *group,
+ const unsigned char *src)
{
struct net_bridge_mdb_entry *mp;
struct net_bridge_port_group *p;
@@ -682,13 +704,13 @@ static int br_multicast_add_group(struct
for (pp = &mp->ports;
(p = mlock_dereference(*pp, br)) != NULL;
pp = &p->next) {
- if (p->port == port)
+ if (br_port_group_equal(p, port, src))
goto found;
if ((unsigned long)p->port < (unsigned long)port)
break;
}
- p = br_multicast_new_port_group(port, group, *pp, MDB_TEMPORARY);
+ p = br_multicast_new_port_group(port, group, *pp, MDB_TEMPORARY, src);
if (unlikely(!p))
goto err;
rcu_assign_pointer(*pp, p);
@@ -707,7 +729,7 @@ err:
static int br_ip4_multicast_add_group(struct net_bridge *br,
struct net_bridge_port *port,
__be32 group,
- __u16 vid)
+ __u16 vid, const unsigned char *src)
{
struct br_ip br_group;
@@ -718,14 +740,14 @@ static int br_ip4_multicast_add_group(st
br_group.proto = htons(ETH_P_IP);
br_group.vid = vid;
- return br_multicast_add_group(br, port, &br_group);
+ return br_multicast_add_group(br, port, &br_group, src);
}
#if IS_ENABLED(CONFIG_IPV6)
static int br_ip6_multicast_add_group(struct net_bridge *br,
struct net_bridge_port *port,
const struct in6_addr *group,
- __u16 vid)
+ __u16 vid, const unsigned char *src)
{
struct br_ip br_group;
@@ -736,7 +758,7 @@ static int br_ip6_multicast_add_group(st
br_group.proto = htons(ETH_P_IPV6);
br_group.vid = vid;
- return br_multicast_add_group(br, port, &br_group);
+ return br_multicast_add_group(br, port, &br_group, src);
}
#endif
@@ -966,6 +988,7 @@ static int br_ip4_multicast_igmp3_report
struct sk_buff *skb,
u16 vid)
{
+ const unsigned char *src;
struct igmpv3_report *ih;
struct igmpv3_grec *grec;
int i;
@@ -1009,7 +1032,8 @@ static int br_ip4_multicast_igmp3_report
continue;
}
- err = br_ip4_multicast_add_group(br, port, group, vid);
+ src = eth_hdr(skb)->h_source;
+ err = br_ip4_multicast_add_group(br, port, group, vid, src);
if (err)
break;
}
@@ -1023,6 +1047,7 @@ static int br_ip6_multicast_mld2_report(
struct sk_buff *skb,
u16 vid)
{
+ const unsigned char *src = eth_hdr(skb)->h_source;
struct icmp6hdr *icmp6h;
struct mld2_grec *grec;
int i;
@@ -1071,7 +1096,7 @@ static int br_ip6_multicast_mld2_report(
}
err = br_ip6_multicast_add_group(br, port, &grec->grec_mca,
- vid);
+ vid, src);
if (err)
break;
}
@@ -1407,7 +1432,8 @@ br_multicast_leave_group(struct net_brid
struct net_bridge_port *port,
struct br_ip *group,
struct bridge_mcast_other_query *other_query,
- struct bridge_mcast_own_query *own_query)
+ struct bridge_mcast_own_query *own_query,
+ const unsigned char *src)
{
struct net_bridge_mdb_htable *mdb;
struct net_bridge_mdb_entry *mp;
@@ -1457,7 +1483,7 @@ br_multicast_leave_group(struct net_brid
for (pp = &mp->ports;
(p = mlock_dereference(*pp, br)) != NULL;
pp = &p->next) {
- if (p->port != port)
+ if (!br_port_group_equal(p, port, src))
continue;
rcu_assign_pointer(*pp, p->next);
@@ -1491,7 +1517,7 @@ br_multicast_leave_group(struct net_brid
for (p = mlock_dereference(mp->ports, br);
p != NULL;
p = mlock_dereference(p->next, br)) {
- if (p->port != port)
+ if (!br_port_group_equal(p, port, src))
continue;
if (!hlist_unhashed(&p->mglist) &&
@@ -1509,8 +1535,8 @@ out:
static void br_ip4_multicast_leave_group(struct net_bridge *br,
struct net_bridge_port *port,
- __be32 group,
- __u16 vid)
+ __be32 group, __u16 vid,
+ const unsigned char *src)
{
struct br_ip br_group;
struct bridge_mcast_own_query *own_query;
@@ -1525,14 +1551,14 @@ static void br_ip4_multicast_leave_group
br_group.vid = vid;
br_multicast_leave_group(br, port, &br_group, &br->ip4_other_query,
- own_query);
+ own_query, src);
}
#if IS_ENABLED(CONFIG_IPV6)
static void br_ip6_multicast_leave_group(struct net_bridge *br,
struct net_bridge_port *port,
const struct in6_addr *group,
- __u16 vid)
+ __u16 vid, const unsigned char *src)
{
struct br_ip br_group;
struct bridge_mcast_own_query *own_query;
@@ -1547,7 +1573,7 @@ static void br_ip6_multicast_leave_group
br_group.vid = vid;
br_multicast_leave_group(br, port, &br_group, &br->ip6_other_query,
- own_query);
+ own_query, src);
}
#endif
@@ -1556,6 +1582,7 @@ static int br_multicast_ipv4_rcv(struct
struct sk_buff *skb,
u16 vid)
{
+ const unsigned char *src;
struct sk_buff *skb2 = skb;
const struct iphdr *iph;
struct igmphdr *ih;
@@ -1624,12 +1651,13 @@ static int br_multicast_ipv4_rcv(struct
BR_INPUT_SKB_CB(skb)->igmp = 1;
ih = igmp_hdr(skb2);
+ src = eth_hdr(skb)->h_source;
switch (ih->type) {
case IGMP_HOST_MEMBERSHIP_REPORT:
case IGMPV2_HOST_MEMBERSHIP_REPORT:
BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
- err = br_ip4_multicast_add_group(br, port, ih->group, vid);
+ err = br_ip4_multicast_add_group(br, port, ih->group, vid, src);
break;
case IGMPV3_HOST_MEMBERSHIP_REPORT:
err = br_ip4_multicast_igmp3_report(br, port, skb2, vid);
@@ -1638,7 +1666,7 @@ static int br_multicast_ipv4_rcv(struct
err = br_ip4_multicast_query(br, port, skb2, vid);
break;
case IGMP_HOST_LEAVE_MESSAGE:
- br_ip4_multicast_leave_group(br, port, ih->group, vid);
+ br_ip4_multicast_leave_group(br, port, ih->group, vid, src);
break;
}
@@ -1656,6 +1684,7 @@ static int br_multicast_ipv6_rcv(struct
struct sk_buff *skb,
u16 vid)
{
+ const unsigned char *src;
struct sk_buff *skb2;
const struct ipv6hdr *ip6h;
u8 icmp6_type;
@@ -1763,9 +1792,11 @@ static int br_multicast_ipv6_rcv(struct
err = -EINVAL;
goto out;
}
+ src = eth_hdr(skb)->h_source;
mld = (struct mld_msg *)skb_transport_header(skb2);
BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
- err = br_ip6_multicast_add_group(br, port, &mld->mld_mca, vid);
+ err = br_ip6_multicast_add_group(br, port, &mld->mld_mca, vid,
+ src);
break;
}
case ICMPV6_MLD2_REPORT:
@@ -1781,8 +1812,9 @@ static int br_multicast_ipv6_rcv(struct
err = -EINVAL;
goto out;
}
+ src = eth_hdr(skb)->h_source;
mld = (struct mld_msg *)skb_transport_header(skb2);
- br_ip6_multicast_leave_group(br, port, &mld->mld_mca, vid);
+ br_ip6_multicast_leave_group(br, port, &mld->mld_mca, vid, src);
}
}
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -113,6 +113,9 @@ struct net_bridge_port_group {
struct timer_list timer;
struct br_ip addr;
unsigned char state;
+
+ unsigned char eth_addr[ETH_ALEN];
+ bool unicast;
};
struct net_bridge_mdb_entry
@@ -481,7 +484,8 @@ void br_multicast_free_pg(struct rcu_hea
struct net_bridge_port_group *
br_multicast_new_port_group(struct net_bridge_port *port, struct br_ip *group,
struct net_bridge_port_group __rcu *next,
- unsigned char state);
+ unsigned char state,
+ const unsigned char *src);
void br_mdb_init(void);
void br_mdb_uninit(void);
void br_mdb_notify(struct net_device *dev, struct net_bridge_port *port,
--- a/net/bridge/br_mdb.c
+++ b/net/bridge/br_mdb.c
@@ -343,7 +343,7 @@ static int br_mdb_add_group(struct net_b
break;
}
- p = br_multicast_new_port_group(port, group, *pp, state);
+ p = br_multicast_new_port_group(port, group, *pp, state, NULL);
if (unlikely(!p))
return -ENOMEM;
rcu_assign_pointer(*pp, p);
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -169,6 +169,34 @@ out:
return p;
}
+static struct net_bridge_port *maybe_deliver_addr(
+ struct net_bridge_port *prev, struct net_bridge_port *p,
+ struct sk_buff *skb, const unsigned char *addr,
+ void (*__packet_hook)(const struct net_bridge_port *p,
+ struct sk_buff *skb))
+{
+ struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
+ const unsigned char *src = eth_hdr(skb)->h_source;
+
+ if (!should_deliver(p, skb))
+ return prev;
+
+ /* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
+ if (skb->dev == p->dev && ether_addr_equal(src, addr))
+ return prev;
+
+ skb = skb_copy(skb, GFP_ATOMIC);
+ if (!skb) {
+ dev->stats.tx_dropped++;
+ return prev;
+ }
+
+ memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
+ __packet_hook(p, skb);
+
+ return prev;
+}
+
/* called under bridge lock */
static void br_flood(struct net_bridge *br, struct sk_buff *skb,
struct sk_buff *skb0,
@@ -241,6 +269,7 @@ static void br_multicast_flood(struct ne
struct net_bridge_port *prev = NULL;
struct net_bridge_port_group *p;
struct hlist_node *rp;
+ const unsigned char *addr;
rp = rcu_dereference(hlist_first_rcu(&br->router_list));
p = mdst ? rcu_dereference(mdst->ports) : NULL;
@@ -251,10 +280,19 @@ static void br_multicast_flood(struct ne
rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
NULL;
- port = (unsigned long)lport > (unsigned long)rport ?
- lport : rport;
-
- prev = maybe_deliver(prev, port, skb, __packet_hook);
+ if ((unsigned long)lport > (unsigned long)rport) {
+ port = lport;
+ addr = p->unicast ? p->eth_addr : NULL;
+ } else {
+ port = rport;
+ addr = NULL;
+ }
+
+ if (addr)
+ prev = maybe_deliver_addr(prev, port, skb, addr,
+ __packet_hook);
+ else
+ prev = maybe_deliver(prev, port, skb, __packet_hook);
if (IS_ERR(prev))
goto out;
--- a/net/bridge/br_sysfs_if.c
+++ b/net/bridge/br_sysfs_if.c
@@ -204,6 +204,7 @@ static BRPORT_ATTR(multicast_router, S_I
store_multicast_router);
BRPORT_ATTR_FLAG(multicast_fast_leave, BR_MULTICAST_FAST_LEAVE);
+BRPORT_ATTR_FLAG(multicast_to_unicast, BR_MULTICAST_TO_UCAST);
#endif
static const struct brport_attribute *brport_attrs[] = {
@@ -230,6 +231,7 @@ static const struct brport_attribute *br
#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
&brport_attr_multicast_router,
&brport_attr_multicast_fast_leave,
+ &brport_attr_multicast_to_unicast,
#endif
&brport_attr_proxyarp,
&brport_attr_proxyarp_wifi,
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