1 From: Felix Fietkau <nbd@nbd.name>
2 Date: Thu, 19 Jan 2017 03:45:10 +0100
3 Subject: [PATCH] bridge: multicast to unicast
5 Content-Type: text/plain; charset=UTF-8
6 Content-Transfer-Encoding: 8bit
8 Implements an optional, per bridge port flag and feature to deliver
9 multicast packets to any host on the according port via unicast
10 individually. This is done by copying the packet per host and
11 changing the multicast destination MAC to a unicast one accordingly.
13 multicast-to-unicast works on top of the multicast snooping feature of
14 the bridge. Which means unicast copies are only delivered to hosts which
15 are interested in it and signalized this via IGMP/MLD reports
18 This feature is intended for interface types which have a more reliable
19 and/or efficient way to deliver unicast packets than broadcast ones
22 However, it should only be enabled on interfaces where no IGMPv2/MLDv1
23 report suppression takes place. This feature is disabled by default.
25 The initial patch and idea is from Felix Fietkau.
27 Signed-off-by: Felix Fietkau <nbd@nbd.name>
28 [linus.luessing@c0d3.blue: various bug + style fixes, commit message]
29 Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
32 --- a/include/linux/if_bridge.h
33 +++ b/include/linux/if_bridge.h
34 @@ -46,6 +46,7 @@ struct br_ip_list {
35 #define BR_LEARNING_SYNC BIT(9)
36 #define BR_PROXYARP_WIFI BIT(10)
37 #define BR_MCAST_FLOOD BIT(11)
38 +#define BR_MULTICAST_TO_UNICAST BIT(12)
40 #define BR_DEFAULT_AGEING_TIME (300 * HZ)
42 --- a/include/uapi/linux/if_link.h
43 +++ b/include/uapi/linux/if_link.h
44 @@ -319,6 +319,7 @@ enum {
45 IFLA_BRPORT_MULTICAST_ROUTER,
47 IFLA_BRPORT_MCAST_FLOOD,
48 + IFLA_BRPORT_MCAST_TO_UCAST,
51 #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)
52 --- a/net/bridge/br_forward.c
53 +++ b/net/bridge/br_forward.c
54 @@ -174,6 +174,29 @@ out:
58 +static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
59 + const unsigned char *addr, bool local_orig)
61 + struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
62 + const unsigned char *src = eth_hdr(skb)->h_source;
64 + if (!should_deliver(p, skb))
67 + /* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
68 + if (skb->dev == p->dev && ether_addr_equal(src, addr))
71 + skb = skb_copy(skb, GFP_ATOMIC);
73 + dev->stats.tx_dropped++;
77 + memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
78 + __br_forward(p, skb, local_orig);
81 /* called under rcu_read_lock */
82 void br_flood(struct net_bridge *br, struct sk_buff *skb,
83 enum br_pkt_type pkt_type, bool local_rcv, bool local_orig)
84 @@ -242,10 +265,20 @@ void br_multicast_flood(struct net_bridg
85 rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
88 - port = (unsigned long)lport > (unsigned long)rport ?
90 + if ((unsigned long)lport > (unsigned long)rport) {
93 + if (p->flags & MDB_PG_FLAGS_MCAST_TO_UCAST) {
94 + maybe_deliver_addr(lport, skb, p->eth_addr,
102 prev = maybe_deliver(prev, port, skb, local_orig);
107 --- a/net/bridge/br_mdb.c
108 +++ b/net/bridge/br_mdb.c
109 @@ -531,7 +531,7 @@ static int br_mdb_add_group(struct net_b
113 - p = br_multicast_new_port_group(port, group, *pp, state);
114 + p = br_multicast_new_port_group(port, group, *pp, state, NULL);
117 rcu_assign_pointer(*pp, p);
118 --- a/net/bridge/br_multicast.c
119 +++ b/net/bridge/br_multicast.c
120 @@ -42,12 +42,14 @@ static void br_multicast_add_router(stru
121 static void br_ip4_multicast_leave_group(struct net_bridge *br,
122 struct net_bridge_port *port,
126 + const unsigned char *src);
128 #if IS_ENABLED(CONFIG_IPV6)
129 static void br_ip6_multicast_leave_group(struct net_bridge *br,
130 struct net_bridge_port *port,
131 const struct in6_addr *group,
133 + __u16 vid, const unsigned char *src);
135 unsigned int br_mdb_rehash_seq;
137 @@ -658,7 +660,8 @@ struct net_bridge_port_group *br_multica
138 struct net_bridge_port *port,
140 struct net_bridge_port_group __rcu *next,
141 - unsigned char flags)
142 + unsigned char flags,
143 + const unsigned char *src)
145 struct net_bridge_port_group *p;
147 @@ -673,12 +676,39 @@ struct net_bridge_port_group *br_multica
148 hlist_add_head(&p->mglist, &port->mglist);
149 setup_timer(&p->timer, br_multicast_port_group_expired,
152 + if ((port->flags & BR_MULTICAST_TO_UNICAST) && src) {
153 + memcpy(p->eth_addr, src, ETH_ALEN);
154 + p->flags |= MDB_PG_FLAGS_MCAST_TO_UCAST;
160 +static bool br_port_group_equal(struct net_bridge_port_group *p,
161 + struct net_bridge_port *port,
162 + const unsigned char *src)
164 + if (p->port != port)
167 + if (!(p->flags & MDB_PG_FLAGS_MCAST_TO_UCAST) !=
168 + !(port->flags & BR_MULTICAST_TO_UNICAST))
171 + if (!(p->flags & MDB_PG_FLAGS_MCAST_TO_UCAST))
177 + return ether_addr_equal(src, p->eth_addr);
180 static int br_multicast_add_group(struct net_bridge *br,
181 struct net_bridge_port *port,
182 - struct br_ip *group)
183 + struct br_ip *group,
184 + const unsigned char *src)
186 struct net_bridge_mdb_entry *mp;
187 struct net_bridge_port_group *p;
188 @@ -705,13 +735,13 @@ static int br_multicast_add_group(struct
189 for (pp = &mp->ports;
190 (p = mlock_dereference(*pp, br)) != NULL;
192 - if (p->port == port)
193 + if (br_port_group_equal(p, port, src))
195 if ((unsigned long)p->port < (unsigned long)port)
199 - p = br_multicast_new_port_group(port, group, *pp, 0);
200 + p = br_multicast_new_port_group(port, group, *pp, 0, src);
203 rcu_assign_pointer(*pp, p);
204 @@ -730,7 +760,8 @@ err:
205 static int br_ip4_multicast_add_group(struct net_bridge *br,
206 struct net_bridge_port *port,
210 + const unsigned char *src)
212 struct br_ip br_group;
214 @@ -741,14 +772,15 @@ static int br_ip4_multicast_add_group(st
215 br_group.proto = htons(ETH_P_IP);
218 - return br_multicast_add_group(br, port, &br_group);
219 + return br_multicast_add_group(br, port, &br_group, src);
222 #if IS_ENABLED(CONFIG_IPV6)
223 static int br_ip6_multicast_add_group(struct net_bridge *br,
224 struct net_bridge_port *port,
225 const struct in6_addr *group,
228 + const unsigned char *src)
230 struct br_ip br_group;
232 @@ -759,7 +791,7 @@ static int br_ip6_multicast_add_group(st
233 br_group.proto = htons(ETH_P_IPV6);
236 - return br_multicast_add_group(br, port, &br_group);
237 + return br_multicast_add_group(br, port, &br_group, src);
241 @@ -1028,6 +1060,7 @@ static int br_ip4_multicast_igmp3_report
245 + const unsigned char *src;
246 struct igmpv3_report *ih;
247 struct igmpv3_grec *grec;
249 @@ -1068,12 +1101,14 @@ static int br_ip4_multicast_igmp3_report
253 + src = eth_hdr(skb)->h_source;
254 if ((type == IGMPV3_CHANGE_TO_INCLUDE ||
255 type == IGMPV3_MODE_IS_INCLUDE) &&
256 ntohs(grec->grec_nsrcs) == 0) {
257 - br_ip4_multicast_leave_group(br, port, group, vid);
258 + br_ip4_multicast_leave_group(br, port, group, vid, src);
260 - err = br_ip4_multicast_add_group(br, port, group, vid);
261 + err = br_ip4_multicast_add_group(br, port, group, vid,
266 @@ -1088,6 +1123,7 @@ static int br_ip6_multicast_mld2_report(
270 + const unsigned char *src = eth_hdr(skb)->h_source;
271 struct icmp6hdr *icmp6h;
272 struct mld2_grec *grec;
274 @@ -1139,10 +1175,11 @@ static int br_ip6_multicast_mld2_report(
275 grec->grec_type == MLD2_MODE_IS_INCLUDE) &&
276 ntohs(*nsrcs) == 0) {
277 br_ip6_multicast_leave_group(br, port, &grec->grec_mca,
281 err = br_ip6_multicast_add_group(br, port,
282 - &grec->grec_mca, vid);
283 + &grec->grec_mca, vid,
288 @@ -1458,7 +1495,8 @@ br_multicast_leave_group(struct net_brid
289 struct net_bridge_port *port,
291 struct bridge_mcast_other_query *other_query,
292 - struct bridge_mcast_own_query *own_query)
293 + struct bridge_mcast_own_query *own_query,
294 + const unsigned char *src)
296 struct net_bridge_mdb_htable *mdb;
297 struct net_bridge_mdb_entry *mp;
298 @@ -1482,7 +1520,7 @@ br_multicast_leave_group(struct net_brid
299 for (pp = &mp->ports;
300 (p = mlock_dereference(*pp, br)) != NULL;
302 - if (p->port != port)
303 + if (!br_port_group_equal(p, port, src))
306 rcu_assign_pointer(*pp, p->next);
307 @@ -1513,7 +1551,7 @@ br_multicast_leave_group(struct net_brid
308 for (p = mlock_dereference(mp->ports, br);
310 p = mlock_dereference(p->next, br)) {
311 - if (p->port != port)
312 + if (!br_port_group_equal(p, port, src))
315 if (!hlist_unhashed(&p->mglist) &&
316 @@ -1564,7 +1602,8 @@ out:
317 static void br_ip4_multicast_leave_group(struct net_bridge *br,
318 struct net_bridge_port *port,
322 + const unsigned char *src)
324 struct br_ip br_group;
325 struct bridge_mcast_own_query *own_query;
326 @@ -1579,14 +1618,15 @@ static void br_ip4_multicast_leave_group
329 br_multicast_leave_group(br, port, &br_group, &br->ip4_other_query,
334 #if IS_ENABLED(CONFIG_IPV6)
335 static void br_ip6_multicast_leave_group(struct net_bridge *br,
336 struct net_bridge_port *port,
337 const struct in6_addr *group,
340 + const unsigned char *src)
342 struct br_ip br_group;
343 struct bridge_mcast_own_query *own_query;
344 @@ -1601,7 +1641,7 @@ static void br_ip6_multicast_leave_group
347 br_multicast_leave_group(br, port, &br_group, &br->ip6_other_query,
353 @@ -1644,6 +1684,7 @@ static int br_multicast_ipv4_rcv(struct
356 struct sk_buff *skb_trimmed = NULL;
357 + const unsigned char *src;
361 @@ -1659,13 +1700,14 @@ static int br_multicast_ipv4_rcv(struct
365 + src = eth_hdr(skb)->h_source;
366 BR_INPUT_SKB_CB(skb)->igmp = ih->type;
369 case IGMP_HOST_MEMBERSHIP_REPORT:
370 case IGMPV2_HOST_MEMBERSHIP_REPORT:
371 BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
372 - err = br_ip4_multicast_add_group(br, port, ih->group, vid);
373 + err = br_ip4_multicast_add_group(br, port, ih->group, vid, src);
375 case IGMPV3_HOST_MEMBERSHIP_REPORT:
376 err = br_ip4_multicast_igmp3_report(br, port, skb_trimmed, vid);
377 @@ -1674,7 +1716,7 @@ static int br_multicast_ipv4_rcv(struct
378 err = br_ip4_multicast_query(br, port, skb_trimmed, vid);
380 case IGMP_HOST_LEAVE_MESSAGE:
381 - br_ip4_multicast_leave_group(br, port, ih->group, vid);
382 + br_ip4_multicast_leave_group(br, port, ih->group, vid, src);
386 @@ -1694,6 +1736,7 @@ static int br_multicast_ipv6_rcv(struct
389 struct sk_buff *skb_trimmed = NULL;
390 + const unsigned char *src;
394 @@ -1713,8 +1756,10 @@ static int br_multicast_ipv6_rcv(struct
396 switch (mld->mld_type) {
397 case ICMPV6_MGM_REPORT:
398 + src = eth_hdr(skb)->h_source;
399 BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
400 - err = br_ip6_multicast_add_group(br, port, &mld->mld_mca, vid);
401 + err = br_ip6_multicast_add_group(br, port, &mld->mld_mca, vid,
404 case ICMPV6_MLD2_REPORT:
405 err = br_ip6_multicast_mld2_report(br, port, skb_trimmed, vid);
406 @@ -1723,7 +1768,8 @@ static int br_multicast_ipv6_rcv(struct
407 err = br_ip6_multicast_query(br, port, skb_trimmed, vid);
409 case ICMPV6_MGM_REDUCTION:
410 - br_ip6_multicast_leave_group(br, port, &mld->mld_mca, vid);
411 + src = eth_hdr(skb)->h_source;
412 + br_ip6_multicast_leave_group(br, port, &mld->mld_mca, vid, src);
416 --- a/net/bridge/br_netlink.c
417 +++ b/net/bridge/br_netlink.c
418 @@ -123,6 +123,7 @@ static inline size_t br_port_info_size(v
419 + nla_total_size(1) /* IFLA_BRPORT_GUARD */
420 + nla_total_size(1) /* IFLA_BRPORT_PROTECT */
421 + nla_total_size(1) /* IFLA_BRPORT_FAST_LEAVE */
422 + + nla_total_size(1) /* IFLA_BRPORT_MCAST_TO_UCAST */
423 + nla_total_size(1) /* IFLA_BRPORT_LEARNING */
424 + nla_total_size(1) /* IFLA_BRPORT_UNICAST_FLOOD */
425 + nla_total_size(1) /* IFLA_BRPORT_PROXYARP */
426 @@ -173,6 +174,8 @@ static int br_port_fill_attrs(struct sk_
427 !!(p->flags & BR_ROOT_BLOCK)) ||
428 nla_put_u8(skb, IFLA_BRPORT_FAST_LEAVE,
429 !!(p->flags & BR_MULTICAST_FAST_LEAVE)) ||
430 + nla_put_u8(skb, IFLA_BRPORT_MCAST_TO_UCAST,
431 + !!(p->flags & BR_MULTICAST_TO_UNICAST)) ||
432 nla_put_u8(skb, IFLA_BRPORT_LEARNING, !!(p->flags & BR_LEARNING)) ||
433 nla_put_u8(skb, IFLA_BRPORT_UNICAST_FLOOD,
434 !!(p->flags & BR_FLOOD)) ||
435 @@ -586,6 +589,7 @@ static const struct nla_policy br_port_p
436 [IFLA_BRPORT_PROXYARP] = { .type = NLA_U8 },
437 [IFLA_BRPORT_PROXYARP_WIFI] = { .type = NLA_U8 },
438 [IFLA_BRPORT_MULTICAST_ROUTER] = { .type = NLA_U8 },
439 + [IFLA_BRPORT_MCAST_TO_UCAST] = { .type = NLA_U8 },
442 /* Change the state of the port and notify spanning tree */
443 @@ -636,6 +640,7 @@ static int br_setport(struct net_bridge_
444 br_set_port_flag(p, tb, IFLA_BRPORT_LEARNING, BR_LEARNING);
445 br_set_port_flag(p, tb, IFLA_BRPORT_UNICAST_FLOOD, BR_FLOOD);
446 br_set_port_flag(p, tb, IFLA_BRPORT_MCAST_FLOOD, BR_MCAST_FLOOD);
447 + br_set_port_flag(p, tb, IFLA_BRPORT_MCAST_TO_UCAST, BR_MULTICAST_TO_UNICAST);
448 br_set_port_flag(p, tb, IFLA_BRPORT_PROXYARP, BR_PROXYARP);
449 br_set_port_flag(p, tb, IFLA_BRPORT_PROXYARP_WIFI, BR_PROXYARP_WIFI);
451 --- a/net/bridge/br_private.h
452 +++ b/net/bridge/br_private.h
453 @@ -166,8 +166,9 @@ struct net_bridge_fdb_entry
457 -#define MDB_PG_FLAGS_PERMANENT BIT(0)
458 -#define MDB_PG_FLAGS_OFFLOAD BIT(1)
459 +#define MDB_PG_FLAGS_PERMANENT BIT(0)
460 +#define MDB_PG_FLAGS_OFFLOAD BIT(1)
461 +#define MDB_PG_FLAGS_MCAST_TO_UCAST BIT(2)
463 struct net_bridge_port_group {
464 struct net_bridge_port *port;
465 @@ -177,6 +178,7 @@ struct net_bridge_port_group {
466 struct timer_list timer;
469 + unsigned char eth_addr[ETH_ALEN];
472 struct net_bridge_mdb_entry
473 @@ -591,7 +593,7 @@ void br_multicast_free_pg(struct rcu_hea
474 struct net_bridge_port_group *
475 br_multicast_new_port_group(struct net_bridge_port *port, struct br_ip *group,
476 struct net_bridge_port_group __rcu *next,
477 - unsigned char flags);
478 + unsigned char flags, const unsigned char *src);
479 void br_mdb_init(void);
480 void br_mdb_uninit(void);
481 void br_mdb_notify(struct net_device *dev, struct net_bridge_port *port,
482 --- a/net/bridge/br_sysfs_if.c
483 +++ b/net/bridge/br_sysfs_if.c
484 @@ -188,6 +188,7 @@ static BRPORT_ATTR(multicast_router, S_I
485 store_multicast_router);
487 BRPORT_ATTR_FLAG(multicast_fast_leave, BR_MULTICAST_FAST_LEAVE);
488 +BRPORT_ATTR_FLAG(multicast_to_unicast, BR_MULTICAST_TO_UNICAST);
491 static const struct brport_attribute *brport_attrs[] = {
492 @@ -214,6 +215,7 @@ static const struct brport_attribute *br
493 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
494 &brport_attr_multicast_router,
495 &brport_attr_multicast_fast_leave,
496 + &brport_attr_multicast_to_unicast,
498 &brport_attr_proxyarp,
499 &brport_attr_proxyarp_wifi,