1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Handle bridge arp/nd proxy/suppress
4 *
5 * Copyright (C) 2017 Cumulus Networks
6 * Copyright (c) 2017 Roopa Prabhu <roopa@cumulusnetworks.com>
7 *
8 * Authors:
9 * Roopa Prabhu <roopa@cumulusnetworks.com>
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/netdevice.h>
14 #include <linux/etherdevice.h>
15 #include <linux/neighbour.h>
16 #include <net/arp.h>
17 #include <linux/if_vlan.h>
18 #include <linux/inetdevice.h>
19 #include <net/addrconf.h>
20 #include <net/ipv6_stubs.h>
21 #if IS_ENABLED(CONFIG_IPV6)
22 #include <net/ip6_checksum.h>
23 #endif
24
25 #include "br_private.h"
26
br_recalculate_neigh_suppress_enabled(struct net_bridge * br)27 void br_recalculate_neigh_suppress_enabled(struct net_bridge *br)
28 {
29 struct net_bridge_port *p;
30 bool neigh_suppress = false;
31
32 list_for_each_entry(p, &br->port_list, list) {
33 if (p->flags & (BR_NEIGH_SUPPRESS | BR_NEIGH_VLAN_SUPPRESS)) {
34 neigh_suppress = true;
35 break;
36 }
37 }
38
39 br_opt_toggle(br, BROPT_NEIGH_SUPPRESS_ENABLED, neigh_suppress);
40 }
41
42 #if IS_ENABLED(CONFIG_INET)
br_arp_send(struct net_bridge * br,struct net_bridge_port * p,struct net_device * dev,__be32 dest_ip,__be32 src_ip,const unsigned char * dest_hw,const unsigned char * src_hw,const unsigned char * target_hw,__be16 vlan_proto,u16 vlan_tci)43 static void br_arp_send(struct net_bridge *br, struct net_bridge_port *p,
44 struct net_device *dev, __be32 dest_ip, __be32 src_ip,
45 const unsigned char *dest_hw,
46 const unsigned char *src_hw,
47 const unsigned char *target_hw,
48 __be16 vlan_proto, u16 vlan_tci)
49 {
50 struct net_bridge_vlan_group *vg;
51 struct sk_buff *skb;
52 u16 pvid;
53
54 netdev_dbg(dev, "arp send dev %s dst %pI4 dst_hw %pM src %pI4 src_hw %pM\n",
55 dev->name, &dest_ip, dest_hw, &src_ip, src_hw);
56
57 if (!vlan_tci) {
58 arp_send(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip,
59 dest_hw, src_hw, target_hw);
60 return;
61 }
62
63 skb = arp_create(ARPOP_REPLY, ETH_P_ARP, dest_ip, dev, src_ip,
64 dest_hw, src_hw, target_hw);
65 if (!skb)
66 return;
67
68 if (p)
69 vg = nbp_vlan_group_rcu(p);
70 else
71 vg = br_vlan_group_rcu(br);
72 pvid = br_get_pvid(vg);
73 if (pvid == (vlan_tci & VLAN_VID_MASK))
74 vlan_tci = 0;
75
76 if (vlan_tci)
77 __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
78
79 if (p) {
80 arp_xmit(skb);
81 } else {
82 skb_reset_mac_header(skb);
83 __skb_pull(skb, skb_network_offset(skb));
84 skb->ip_summed = CHECKSUM_UNNECESSARY;
85 skb->pkt_type = PACKET_HOST;
86
87 netif_rx(skb);
88 }
89 }
90
br_chk_addr_ip(struct net_device * dev,struct netdev_nested_priv * priv)91 static int br_chk_addr_ip(struct net_device *dev,
92 struct netdev_nested_priv *priv)
93 {
94 __be32 ip = *(__be32 *)priv->data;
95 struct in_device *in_dev;
96 __be32 addr = 0;
97
98 in_dev = __in_dev_get_rcu(dev);
99 if (in_dev)
100 addr = inet_confirm_addr(dev_net(dev), in_dev, 0, ip,
101 RT_SCOPE_HOST);
102
103 if (addr == ip)
104 return 1;
105
106 return 0;
107 }
108
br_is_local_ip(struct net_device * dev,__be32 ip)109 static bool br_is_local_ip(struct net_device *dev, __be32 ip)
110 {
111 struct netdev_nested_priv priv = {
112 .data = (void *)&ip,
113 };
114
115 if (br_chk_addr_ip(dev, &priv))
116 return true;
117
118 /* check if ip is configured on upper dev */
119 if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip, &priv))
120 return true;
121
122 return false;
123 }
124
br_do_proxy_suppress_arp(struct sk_buff * skb,struct net_bridge * br,u16 vid,struct net_bridge_port * p)125 void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br,
126 u16 vid, struct net_bridge_port *p)
127 {
128 struct net_device *dev = br->dev;
129 struct net_device *vlandev = dev;
130 struct neighbour *n;
131 struct arphdr *parp;
132 u8 *arpptr, *sha;
133 __be32 sip, tip;
134
135 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0;
136
137 if ((dev->flags & IFF_NOARP) ||
138 !pskb_may_pull(skb, arp_hdr_len(dev)))
139 return;
140
141 parp = arp_hdr(skb);
142
143 if (parp->ar_pro != htons(ETH_P_IP) ||
144 parp->ar_hln != dev->addr_len ||
145 parp->ar_pln != 4)
146 return;
147
148 arpptr = (u8 *)parp + sizeof(struct arphdr);
149 sha = arpptr;
150 arpptr += dev->addr_len; /* sha */
151 memcpy(&sip, arpptr, sizeof(sip));
152 arpptr += sizeof(sip);
153 arpptr += dev->addr_len; /* tha */
154 memcpy(&tip, arpptr, sizeof(tip));
155
156 if (ipv4_is_loopback(tip) ||
157 ipv4_is_multicast(tip))
158 return;
159
160 if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED)) {
161 if (br_is_neigh_suppress_enabled(p, vid))
162 return;
163 if (is_unicast_ether_addr(eth_hdr(skb)->h_dest) &&
164 parp->ar_op == htons(ARPOP_REQUEST))
165 return;
166 if (parp->ar_op != htons(ARPOP_RREQUEST) &&
167 parp->ar_op != htons(ARPOP_RREPLY) &&
168 (ipv4_is_zeronet(sip) || sip == tip)) {
169 /* prevent flooding to neigh suppress ports */
170 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
171 return;
172 }
173 }
174
175 if (parp->ar_op != htons(ARPOP_REQUEST))
176 return;
177
178 if (vid != 0) {
179 vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto,
180 vid);
181 if (!vlandev)
182 return;
183 }
184
185 if (br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
186 br_is_local_ip(vlandev, tip)) {
187 /* its our local ip, so don't proxy reply
188 * and don't forward to neigh suppress ports
189 */
190 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
191 return;
192 }
193
194 n = neigh_lookup(&arp_tbl, &tip, vlandev);
195 if (n) {
196 struct net_bridge_fdb_entry *f;
197
198 if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
199 neigh_release(n);
200 return;
201 }
202
203 f = br_fdb_find_rcu(br, n->ha, vid);
204 if (f) {
205 bool replied = false;
206
207 if ((p && (p->flags & BR_PROXYARP)) ||
208 (f->dst && (f->dst->flags & BR_PROXYARP_WIFI)) ||
209 br_is_neigh_suppress_enabled(f->dst, vid)) {
210 if (!vid)
211 br_arp_send(br, p, skb->dev, sip, tip,
212 sha, n->ha, sha, 0, 0);
213 else
214 br_arp_send(br, p, skb->dev, sip, tip,
215 sha, n->ha, sha,
216 skb->vlan_proto,
217 skb_vlan_tag_get(skb));
218 replied = true;
219 }
220
221 /* If we have replied or as long as we know the
222 * mac, indicate to arp replied
223 */
224 if (replied ||
225 br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED))
226 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
227 }
228
229 neigh_release(n);
230 }
231 }
232 #endif
233
234 #if IS_ENABLED(CONFIG_IPV6)
br_is_nd_neigh_msg(const struct sk_buff * skb,struct nd_msg * msg)235 struct nd_msg *br_is_nd_neigh_msg(const struct sk_buff *skb, struct nd_msg *msg)
236 {
237 struct nd_msg *m;
238
239 m = skb_header_pointer(skb, skb_network_offset(skb) +
240 sizeof(struct ipv6hdr), sizeof(*msg), msg);
241 if (!m)
242 return NULL;
243
244 if (m->icmph.icmp6_code != 0 ||
245 (m->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION &&
246 m->icmph.icmp6_type != NDISC_NEIGHBOUR_ADVERTISEMENT))
247 return NULL;
248
249 return m;
250 }
251
br_nd_send(struct net_bridge * br,struct net_bridge_port * p,struct sk_buff * request,struct neighbour * n,__be16 vlan_proto,u16 vlan_tci,struct nd_msg * ns)252 static void br_nd_send(struct net_bridge *br, struct net_bridge_port *p,
253 struct sk_buff *request, struct neighbour *n,
254 __be16 vlan_proto, u16 vlan_tci, struct nd_msg *ns)
255 {
256 struct net_device *dev = request->dev;
257 struct net_bridge_vlan_group *vg;
258 struct sk_buff *reply;
259 struct nd_msg *na;
260 struct ipv6hdr *pip6;
261 int na_olen = 8; /* opt hdr + ETH_ALEN for target */
262 int ns_olen;
263 int i, len;
264 u8 *daddr;
265 u16 pvid;
266
267 if (!dev)
268 return;
269
270 len = LL_RESERVED_SPACE(dev) + sizeof(struct ipv6hdr) +
271 sizeof(*na) + na_olen + dev->needed_tailroom;
272
273 reply = alloc_skb(len, GFP_ATOMIC);
274 if (!reply)
275 return;
276
277 reply->protocol = htons(ETH_P_IPV6);
278 reply->dev = dev;
279 skb_reserve(reply, LL_RESERVED_SPACE(dev));
280 skb_push(reply, sizeof(struct ethhdr));
281 skb_set_mac_header(reply, 0);
282
283 daddr = eth_hdr(request)->h_source;
284
285 /* Do we need option processing ? */
286 ns_olen = request->len - (skb_network_offset(request) +
287 sizeof(struct ipv6hdr)) - sizeof(*ns);
288 for (i = 0; i < ns_olen - 1; i += (ns->opt[i + 1] << 3)) {
289 if (!ns->opt[i + 1]) {
290 kfree_skb(reply);
291 return;
292 }
293 if (ns->opt[i] == ND_OPT_SOURCE_LL_ADDR) {
294 daddr = ns->opt + i + sizeof(struct nd_opt_hdr);
295 break;
296 }
297 }
298
299 /* Ethernet header */
300 ether_addr_copy(eth_hdr(reply)->h_dest, daddr);
301 ether_addr_copy(eth_hdr(reply)->h_source, n->ha);
302 eth_hdr(reply)->h_proto = htons(ETH_P_IPV6);
303 reply->protocol = htons(ETH_P_IPV6);
304
305 skb_pull(reply, sizeof(struct ethhdr));
306 skb_set_network_header(reply, 0);
307 skb_put(reply, sizeof(struct ipv6hdr));
308
309 /* IPv6 header */
310 pip6 = ipv6_hdr(reply);
311 memset(pip6, 0, sizeof(struct ipv6hdr));
312 pip6->version = 6;
313 pip6->priority = ipv6_hdr(request)->priority;
314 pip6->nexthdr = IPPROTO_ICMPV6;
315 pip6->hop_limit = 255;
316 pip6->daddr = ipv6_hdr(request)->saddr;
317 pip6->saddr = *(struct in6_addr *)n->primary_key;
318
319 skb_pull(reply, sizeof(struct ipv6hdr));
320 skb_set_transport_header(reply, 0);
321
322 na = (struct nd_msg *)skb_put(reply, sizeof(*na) + na_olen);
323
324 /* Neighbor Advertisement */
325 memset(na, 0, sizeof(*na) + na_olen);
326 na->icmph.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT;
327 na->icmph.icmp6_router = (n->flags & NTF_ROUTER) ? 1 : 0;
328 na->icmph.icmp6_override = 1;
329 na->icmph.icmp6_solicited = 1;
330 na->target = ns->target;
331 ether_addr_copy(&na->opt[2], n->ha);
332 na->opt[0] = ND_OPT_TARGET_LL_ADDR;
333 na->opt[1] = na_olen >> 3;
334
335 na->icmph.icmp6_cksum = csum_ipv6_magic(&pip6->saddr,
336 &pip6->daddr,
337 sizeof(*na) + na_olen,
338 IPPROTO_ICMPV6,
339 csum_partial(na, sizeof(*na) + na_olen, 0));
340
341 pip6->payload_len = htons(sizeof(*na) + na_olen);
342
343 skb_push(reply, sizeof(struct ipv6hdr));
344 skb_push(reply, sizeof(struct ethhdr));
345
346 reply->ip_summed = CHECKSUM_UNNECESSARY;
347
348 if (p)
349 vg = nbp_vlan_group_rcu(p);
350 else
351 vg = br_vlan_group_rcu(br);
352 pvid = br_get_pvid(vg);
353 if (pvid == (vlan_tci & VLAN_VID_MASK))
354 vlan_tci = 0;
355
356 if (vlan_tci)
357 __vlan_hwaccel_put_tag(reply, vlan_proto, vlan_tci);
358
359 netdev_dbg(dev, "nd send dev %s dst %pI6 dst_hw %pM src %pI6 src_hw %pM\n",
360 dev->name, &pip6->daddr, daddr, &pip6->saddr, n->ha);
361
362 if (p) {
363 dev_queue_xmit(reply);
364 } else {
365 skb_reset_mac_header(reply);
366 __skb_pull(reply, skb_network_offset(reply));
367 reply->ip_summed = CHECKSUM_UNNECESSARY;
368 reply->pkt_type = PACKET_HOST;
369
370 netif_rx(reply);
371 }
372 }
373
br_chk_addr_ip6(struct net_device * dev,struct netdev_nested_priv * priv)374 static int br_chk_addr_ip6(struct net_device *dev,
375 struct netdev_nested_priv *priv)
376 {
377 struct in6_addr *addr = (struct in6_addr *)priv->data;
378
379 if (ipv6_chk_addr(dev_net(dev), addr, dev, 0))
380 return 1;
381
382 return 0;
383 }
384
br_is_local_ip6(struct net_device * dev,struct in6_addr * addr)385 static bool br_is_local_ip6(struct net_device *dev, struct in6_addr *addr)
386
387 {
388 struct netdev_nested_priv priv = {
389 .data = (void *)addr,
390 };
391
392 if (br_chk_addr_ip6(dev, &priv))
393 return true;
394
395 /* check if ip is configured on upper dev */
396 if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip6, &priv))
397 return true;
398
399 return false;
400 }
401
br_do_suppress_nd(struct sk_buff * skb,struct net_bridge * br,u16 vid,struct net_bridge_port * p,struct nd_msg * msg)402 void br_do_suppress_nd(struct sk_buff *skb, struct net_bridge *br,
403 u16 vid, struct net_bridge_port *p, struct nd_msg *msg)
404 {
405 struct net_device *dev = br->dev;
406 struct net_device *vlandev = NULL;
407 struct in6_addr *saddr, *daddr;
408 struct ipv6hdr *iphdr;
409 struct neighbour *n;
410
411 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 0;
412
413 if (br_is_neigh_suppress_enabled(p, vid))
414 return;
415
416 if (is_unicast_ether_addr(eth_hdr(skb)->h_dest) &&
417 msg->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION)
418 return;
419
420 if (msg->icmph.icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT &&
421 !msg->icmph.icmp6_solicited) {
422 /* prevent flooding to neigh suppress ports */
423 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
424 return;
425 }
426
427 if (msg->icmph.icmp6_type != NDISC_NEIGHBOUR_SOLICITATION)
428 return;
429
430 iphdr = ipv6_hdr(skb);
431 saddr = &iphdr->saddr;
432 daddr = &iphdr->daddr;
433
434 if (ipv6_addr_any(saddr) || !ipv6_addr_cmp(saddr, daddr)) {
435 /* prevent flooding to neigh suppress ports */
436 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
437 return;
438 }
439
440 if (vid != 0) {
441 /* build neigh table lookup on the vlan device */
442 vlandev = __vlan_find_dev_deep_rcu(br->dev, skb->vlan_proto,
443 vid);
444 if (!vlandev)
445 return;
446 } else {
447 vlandev = dev;
448 }
449
450 if (br_is_local_ip6(vlandev, &msg->target)) {
451 /* its our own ip, so don't proxy reply
452 * and don't forward to arp suppress ports
453 */
454 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
455 return;
456 }
457
458 n = neigh_lookup(ipv6_stub->nd_tbl, &msg->target, vlandev);
459 if (n) {
460 struct net_bridge_fdb_entry *f;
461
462 if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
463 neigh_release(n);
464 return;
465 }
466
467 f = br_fdb_find_rcu(br, n->ha, vid);
468 if (f) {
469 bool replied = false;
470
471 if (br_is_neigh_suppress_enabled(f->dst, vid)) {
472 if (vid != 0)
473 br_nd_send(br, p, skb, n,
474 skb->vlan_proto,
475 skb_vlan_tag_get(skb), msg);
476 else
477 br_nd_send(br, p, skb, n, 0, 0, msg);
478 replied = true;
479 }
480
481 /* If we have replied or as long as we know the
482 * mac, indicate to NEIGH_SUPPRESS ports that we
483 * have replied
484 */
485 if (replied ||
486 br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED))
487 BR_INPUT_SKB_CB(skb)->proxyarp_replied = 1;
488 }
489 neigh_release(n);
490 }
491 }
492 #endif
493
br_is_neigh_suppress_enabled(const struct net_bridge_port * p,u16 vid)494 bool br_is_neigh_suppress_enabled(const struct net_bridge_port *p, u16 vid)
495 {
496 if (!p)
497 return false;
498
499 if (!vid)
500 return !!(p->flags & BR_NEIGH_SUPPRESS);
501
502 if (p->flags & BR_NEIGH_VLAN_SUPPRESS) {
503 struct net_bridge_vlan_group *vg = nbp_vlan_group_rcu(p);
504 struct net_bridge_vlan *v;
505
506 v = br_vlan_find(vg, vid);
507 if (!v)
508 return false;
509 return !!(v->priv_flags & BR_VLFLAG_NEIGH_SUPPRESS_ENABLED);
510 } else {
511 return !!(p->flags & BR_NEIGH_SUPPRESS);
512 }
513 }
514