~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/bridge/br_input.c

Version: ~ [ linux-5.12-rc7 ] ~ [ linux-5.11.13 ] ~ [ linux-5.10.29 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.111 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.186 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.230 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.266 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.266 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  *      Handle incoming frames
  3  *      Linux ethernet bridge
  4  *
  5  *      Authors:
  6  *      Lennert Buytenhek               <buytenh@gnu.org>
  7  *
  8  *      This program is free software; you can redistribute it and/or
  9  *      modify it under the terms of the GNU General Public License
 10  *      as published by the Free Software Foundation; either version
 11  *      2 of the License, or (at your option) any later version.
 12  */
 13 
 14 #include <linux/slab.h>
 15 #include <linux/kernel.h>
 16 #include <linux/netdevice.h>
 17 #include <linux/etherdevice.h>
 18 #include <linux/netfilter_bridge.h>
 19 #include <linux/neighbour.h>
 20 #include <net/arp.h>
 21 #include <linux/export.h>
 22 #include <linux/rculist.h>
 23 #include "br_private.h"
 24 
 25 /* Hook for brouter */
 26 br_should_route_hook_t __rcu *br_should_route_hook __read_mostly;
 27 EXPORT_SYMBOL(br_should_route_hook);
 28 
 29 static int br_pass_frame_up(struct sk_buff *skb)
 30 {
 31         struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
 32         struct net_bridge *br = netdev_priv(brdev);
 33         struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
 34         struct net_port_vlans *pv;
 35 
 36         u64_stats_update_begin(&brstats->syncp);
 37         brstats->rx_packets++;
 38         brstats->rx_bytes += skb->len;
 39         u64_stats_update_end(&brstats->syncp);
 40 
 41         /* Bridge is just like any other port.  Make sure the
 42          * packet is allowed except in promisc modue when someone
 43          * may be running packet capture.
 44          */
 45         pv = br_get_vlan_info(br);
 46         if (!(brdev->flags & IFF_PROMISC) &&
 47             !br_allowed_egress(br, pv, skb)) {
 48                 kfree_skb(skb);
 49                 return NET_RX_DROP;
 50         }
 51 
 52         indev = skb->dev;
 53         skb->dev = brdev;
 54         skb = br_handle_vlan(br, pv, skb);
 55         if (!skb)
 56                 return NET_RX_DROP;
 57 
 58         return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, NULL, skb,
 59                        indev, NULL,
 60                        netif_receive_skb_sk);
 61 }
 62 
 63 static void br_do_proxy_arp(struct sk_buff *skb, struct net_bridge *br,
 64                             u16 vid, struct net_bridge_port *p)
 65 {
 66         struct net_device *dev = br->dev;
 67         struct neighbour *n;
 68         struct arphdr *parp;
 69         u8 *arpptr, *sha;
 70         __be32 sip, tip;
 71 
 72         BR_INPUT_SKB_CB(skb)->proxyarp_replied = false;
 73 
 74         if (dev->flags & IFF_NOARP)
 75                 return;
 76 
 77         if (!pskb_may_pull(skb, arp_hdr_len(dev))) {
 78                 dev->stats.tx_dropped++;
 79                 return;
 80         }
 81         parp = arp_hdr(skb);
 82 
 83         if (parp->ar_pro != htons(ETH_P_IP) ||
 84             parp->ar_op != htons(ARPOP_REQUEST) ||
 85             parp->ar_hln != dev->addr_len ||
 86             parp->ar_pln != 4)
 87                 return;
 88 
 89         arpptr = (u8 *)parp + sizeof(struct arphdr);
 90         sha = arpptr;
 91         arpptr += dev->addr_len;        /* sha */
 92         memcpy(&sip, arpptr, sizeof(sip));
 93         arpptr += sizeof(sip);
 94         arpptr += dev->addr_len;        /* tha */
 95         memcpy(&tip, arpptr, sizeof(tip));
 96 
 97         if (ipv4_is_loopback(tip) ||
 98             ipv4_is_multicast(tip))
 99                 return;
100 
101         n = neigh_lookup(&arp_tbl, &tip, dev);
102         if (n) {
103                 struct net_bridge_fdb_entry *f;
104 
105                 if (!(n->nud_state & NUD_VALID)) {
106                         neigh_release(n);
107                         return;
108                 }
109 
110                 f = __br_fdb_get(br, n->ha, vid);
111                 if (f && ((p->flags & BR_PROXYARP) ||
112                           (f->dst && (f->dst->flags & BR_PROXYARP_WIFI)))) {
113                         arp_send(ARPOP_REPLY, ETH_P_ARP, sip, skb->dev, tip,
114                                  sha, n->ha, sha);
115                         BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
116                 }
117 
118                 neigh_release(n);
119         }
120 }
121 
122 /* note: already called with rcu_read_lock */
123 int br_handle_frame_finish(struct sock *sk, struct sk_buff *skb)
124 {
125         const unsigned char *dest = eth_hdr(skb)->h_dest;
126         struct net_bridge_port *p = br_port_get_rcu(skb->dev);
127         struct net_bridge *br;
128         struct net_bridge_fdb_entry *dst;
129         struct net_bridge_mdb_entry *mdst;
130         struct sk_buff *skb2;
131         bool unicast = true;
132         u16 vid = 0;
133 
134         if (!p || p->state == BR_STATE_DISABLED)
135                 goto drop;
136 
137         if (!br_allowed_ingress(p->br, nbp_get_vlan_info(p), skb, &vid))
138                 goto out;
139 
140         /* insert into forwarding database after filtering to avoid spoofing */
141         br = p->br;
142         if (p->flags & BR_LEARNING)
143                 br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
144 
145         if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) &&
146             br_multicast_rcv(br, p, skb, vid))
147                 goto drop;
148 
149         if (p->state == BR_STATE_LEARNING)
150                 goto drop;
151 
152         BR_INPUT_SKB_CB(skb)->brdev = br->dev;
153 
154         /* The packet skb2 goes to the local host (NULL to skip). */
155         skb2 = NULL;
156 
157         if (br->dev->flags & IFF_PROMISC)
158                 skb2 = skb;
159 
160         dst = NULL;
161 
162         if (IS_ENABLED(CONFIG_INET) && skb->protocol == htons(ETH_P_ARP))
163                 br_do_proxy_arp(skb, br, vid, p);
164 
165         if (is_broadcast_ether_addr(dest)) {
166                 skb2 = skb;
167                 unicast = false;
168         } else if (is_multicast_ether_addr(dest)) {
169                 mdst = br_mdb_get(br, skb, vid);
170                 if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
171                     br_multicast_querier_exists(br, eth_hdr(skb))) {
172                         if ((mdst && mdst->mglist) ||
173                             br_multicast_is_router(br))
174                                 skb2 = skb;
175                         br_multicast_forward(mdst, skb, skb2);
176                         skb = NULL;
177                         if (!skb2)
178                                 goto out;
179                 } else
180                         skb2 = skb;
181 
182                 unicast = false;
183                 br->dev->stats.multicast++;
184         } else if ((dst = __br_fdb_get(br, dest, vid)) &&
185                         dst->is_local) {
186                 skb2 = skb;
187                 /* Do not forward the packet since it's local. */
188                 skb = NULL;
189         }
190 
191         if (skb) {
192                 if (dst) {
193                         dst->used = jiffies;
194                         br_forward(dst->dst, skb, skb2);
195                 } else
196                         br_flood_forward(br, skb, skb2, unicast);
197         }
198 
199         if (skb2)
200                 return br_pass_frame_up(skb2);
201 
202 out:
203         return 0;
204 drop:
205         kfree_skb(skb);
206         goto out;
207 }
208 EXPORT_SYMBOL_GPL(br_handle_frame_finish);
209 
210 /* note: already called with rcu_read_lock */
211 static int br_handle_local_finish(struct sock *sk, struct sk_buff *skb)
212 {
213         struct net_bridge_port *p = br_port_get_rcu(skb->dev);
214         u16 vid = 0;
215 
216         /* check if vlan is allowed, to avoid spoofing */
217         if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
218                 br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
219         return 0;        /* process further */
220 }
221 
222 /*
223  * Return NULL if skb is handled
224  * note: already called with rcu_read_lock
225  */
226 rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
227 {
228         struct net_bridge_port *p;
229         struct sk_buff *skb = *pskb;
230         const unsigned char *dest = eth_hdr(skb)->h_dest;
231         br_should_route_hook_t *rhook;
232 
233         if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
234                 return RX_HANDLER_PASS;
235 
236         if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
237                 goto drop;
238 
239         skb = skb_share_check(skb, GFP_ATOMIC);
240         if (!skb)
241                 return RX_HANDLER_CONSUMED;
242 
243         p = br_port_get_rcu(skb->dev);
244 
245         if (unlikely(is_link_local_ether_addr(dest))) {
246                 u16 fwd_mask = p->br->group_fwd_mask_required;
247 
248                 /*
249                  * See IEEE 802.1D Table 7-10 Reserved addresses
250                  *
251                  * Assignment                           Value
252                  * Bridge Group Address         01-80-C2-00-00-00
253                  * (MAC Control) 802.3          01-80-C2-00-00-01
254                  * (Link Aggregation) 802.3     01-80-C2-00-00-02
255                  * 802.1X PAE address           01-80-C2-00-00-03
256                  *
257                  * 802.1AB LLDP                 01-80-C2-00-00-0E
258                  *
259                  * Others reserved for future standardization
260                  */
261                 switch (dest[5]) {
262                 case 0x00:      /* Bridge Group Address */
263                         /* If STP is turned off,
264                            then must forward to keep loop detection */
265                         if (p->br->stp_enabled == BR_NO_STP ||
266                             fwd_mask & (1u << dest[5]))
267                                 goto forward;
268                         break;
269 
270                 case 0x01:      /* IEEE MAC (Pause) */
271                         goto drop;
272 
273                 default:
274                         /* Allow selective forwarding for most other protocols */
275                         fwd_mask |= p->br->group_fwd_mask;
276                         if (fwd_mask & (1u << dest[5]))
277                                 goto forward;
278                 }
279 
280                 /* Deliver packet to local host only */
281                 if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, NULL, skb,
282                             skb->dev, NULL, br_handle_local_finish)) {
283                         return RX_HANDLER_CONSUMED; /* consumed by filter */
284                 } else {
285                         *pskb = skb;
286                         return RX_HANDLER_PASS; /* continue processing */
287                 }
288         }
289 
290 forward:
291         switch (p->state) {
292         case BR_STATE_FORWARDING:
293                 rhook = rcu_dereference(br_should_route_hook);
294                 if (rhook) {
295                         if ((*rhook)(skb)) {
296                                 *pskb = skb;
297                                 return RX_HANDLER_PASS;
298                         }
299                         dest = eth_hdr(skb)->h_dest;
300                 }
301                 /* fall through */
302         case BR_STATE_LEARNING:
303                 if (ether_addr_equal(p->br->dev->dev_addr, dest))
304                         skb->pkt_type = PACKET_HOST;
305 
306                 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, NULL, skb,
307                         skb->dev, NULL,
308                         br_handle_frame_finish);
309                 break;
310         default:
311 drop:
312                 kfree_skb(skb);
313         }
314         return RX_HANDLER_CONSUMED;
315 }
316 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp