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

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

Version: ~ [ linux-5.12-rc1 ] ~ [ linux-5.11.2 ] ~ [ linux-5.10.19 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.101 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.177 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.222 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.258 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.258 ] ~ [ 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 #include "br_private_tunnel.h"
 25 
 26 /* Hook for brouter */
 27 br_should_route_hook_t __rcu *br_should_route_hook __read_mostly;
 28 EXPORT_SYMBOL(br_should_route_hook);
 29 
 30 static int
 31 br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb)
 32 {
 33         br_drop_fake_rtable(skb);
 34         return netif_receive_skb(skb);
 35 }
 36 
 37 static int br_pass_frame_up(struct sk_buff *skb)
 38 {
 39         struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
 40         struct net_bridge *br = netdev_priv(brdev);
 41         struct net_bridge_vlan_group *vg;
 42         struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
 43 
 44         u64_stats_update_begin(&brstats->syncp);
 45         brstats->rx_packets++;
 46         brstats->rx_bytes += skb->len;
 47         u64_stats_update_end(&brstats->syncp);
 48 
 49         vg = br_vlan_group_rcu(br);
 50         /* Bridge is just like any other port.  Make sure the
 51          * packet is allowed except in promisc modue when someone
 52          * may be running packet capture.
 53          */
 54         if (!(brdev->flags & IFF_PROMISC) &&
 55             !br_allowed_egress(vg, skb)) {
 56                 kfree_skb(skb);
 57                 return NET_RX_DROP;
 58         }
 59 
 60         indev = skb->dev;
 61         skb->dev = brdev;
 62         skb = br_handle_vlan(br, NULL, vg, skb);
 63         if (!skb)
 64                 return NET_RX_DROP;
 65         /* update the multicast stats if the packet is IGMP/MLD */
 66         br_multicast_count(br, NULL, skb, br_multicast_igmp_type(skb),
 67                            BR_MCAST_DIR_TX);
 68 
 69         return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
 70                        dev_net(indev), NULL, skb, indev, NULL,
 71                        br_netif_receive_skb);
 72 }
 73 
 74 /* note: already called with rcu_read_lock */
 75 int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 76 {
 77         struct net_bridge_port *p = br_port_get_rcu(skb->dev);
 78         enum br_pkt_type pkt_type = BR_PKT_UNICAST;
 79         struct net_bridge_fdb_entry *dst = NULL;
 80         struct net_bridge_mdb_entry *mdst;
 81         bool local_rcv, mcast_hit = false;
 82         const unsigned char *dest;
 83         struct net_bridge *br;
 84         u16 vid = 0;
 85 
 86         if (!p || p->state == BR_STATE_DISABLED)
 87                 goto drop;
 88 
 89         if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid))
 90                 goto out;
 91 
 92         nbp_switchdev_frame_mark(p, skb);
 93 
 94         /* insert into forwarding database after filtering to avoid spoofing */
 95         br = p->br;
 96         if (p->flags & BR_LEARNING)
 97                 br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
 98 
 99         local_rcv = !!(br->dev->flags & IFF_PROMISC);
100         dest = eth_hdr(skb)->h_dest;
101         if (is_multicast_ether_addr(dest)) {
102                 /* by definition the broadcast is also a multicast address */
103                 if (is_broadcast_ether_addr(dest)) {
104                         pkt_type = BR_PKT_BROADCAST;
105                         local_rcv = true;
106                 } else {
107                         pkt_type = BR_PKT_MULTICAST;
108                         if (br_multicast_rcv(br, p, skb, vid))
109                                 goto drop;
110                 }
111         }
112 
113         if (p->state == BR_STATE_LEARNING)
114                 goto drop;
115 
116         BR_INPUT_SKB_CB(skb)->brdev = br->dev;
117 
118         if (IS_ENABLED(CONFIG_INET) &&
119             (skb->protocol == htons(ETH_P_ARP) ||
120              skb->protocol == htons(ETH_P_RARP))) {
121                 br_do_proxy_suppress_arp(skb, br, vid, p);
122         } else if (IS_ENABLED(CONFIG_IPV6) &&
123                    skb->protocol == htons(ETH_P_IPV6) &&
124                    br->neigh_suppress_enabled &&
125                    pskb_may_pull(skb, sizeof(struct ipv6hdr) +
126                                  sizeof(struct nd_msg)) &&
127                    ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
128                         struct nd_msg *msg, _msg;
129 
130                         msg = br_is_nd_neigh_msg(skb, &_msg);
131                         if (msg)
132                                 br_do_suppress_nd(skb, br, vid, p, msg);
133         }
134 
135         switch (pkt_type) {
136         case BR_PKT_MULTICAST:
137                 mdst = br_mdb_get(br, skb, vid);
138                 if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
139                     br_multicast_querier_exists(br, eth_hdr(skb))) {
140                         if ((mdst && mdst->host_joined) ||
141                             br_multicast_is_router(br)) {
142                                 local_rcv = true;
143                                 br->dev->stats.multicast++;
144                         }
145                         mcast_hit = true;
146                 } else {
147                         local_rcv = true;
148                         br->dev->stats.multicast++;
149                 }
150                 break;
151         case BR_PKT_UNICAST:
152                 dst = br_fdb_find_rcu(br, dest, vid);
153         default:
154                 break;
155         }
156 
157         if (dst) {
158                 unsigned long now = jiffies;
159 
160                 if (dst->is_local)
161                         return br_pass_frame_up(skb);
162 
163                 if (now != dst->used)
164                         dst->used = now;
165                 br_forward(dst->dst, skb, local_rcv, false);
166         } else {
167                 if (!mcast_hit)
168                         br_flood(br, skb, pkt_type, local_rcv, false);
169                 else
170                         br_multicast_flood(mdst, skb, local_rcv, false);
171         }
172 
173         if (local_rcv)
174                 return br_pass_frame_up(skb);
175 
176 out:
177         return 0;
178 drop:
179         kfree_skb(skb);
180         goto out;
181 }
182 EXPORT_SYMBOL_GPL(br_handle_frame_finish);
183 
184 static void __br_handle_local_finish(struct sk_buff *skb)
185 {
186         struct net_bridge_port *p = br_port_get_rcu(skb->dev);
187         u16 vid = 0;
188 
189         /* check if vlan is allowed, to avoid spoofing */
190         if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
191                 br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
192 }
193 
194 /* note: already called with rcu_read_lock */
195 static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
196 {
197         struct net_bridge_port *p = br_port_get_rcu(skb->dev);
198 
199         __br_handle_local_finish(skb);
200 
201         BR_INPUT_SKB_CB(skb)->brdev = p->br->dev;
202         br_pass_frame_up(skb);
203         return 0;
204 }
205 
206 /*
207  * Return NULL if skb is handled
208  * note: already called with rcu_read_lock
209  */
210 rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
211 {
212         struct net_bridge_port *p;
213         struct sk_buff *skb = *pskb;
214         const unsigned char *dest = eth_hdr(skb)->h_dest;
215         br_should_route_hook_t *rhook;
216 
217         if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
218                 return RX_HANDLER_PASS;
219 
220         if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
221                 goto drop;
222 
223         skb = skb_share_check(skb, GFP_ATOMIC);
224         if (!skb)
225                 return RX_HANDLER_CONSUMED;
226 
227         p = br_port_get_rcu(skb->dev);
228         if (p->flags & BR_VLAN_TUNNEL) {
229                 if (br_handle_ingress_vlan_tunnel(skb, p,
230                                                   nbp_vlan_group_rcu(p)))
231                         goto drop;
232         }
233 
234         if (unlikely(is_link_local_ether_addr(dest))) {
235                 u16 fwd_mask = p->br->group_fwd_mask_required;
236 
237                 /*
238                  * See IEEE 802.1D Table 7-10 Reserved addresses
239                  *
240                  * Assignment                           Value
241                  * Bridge Group Address         01-80-C2-00-00-00
242                  * (MAC Control) 802.3          01-80-C2-00-00-01
243                  * (Link Aggregation) 802.3     01-80-C2-00-00-02
244                  * 802.1X PAE address           01-80-C2-00-00-03
245                  *
246                  * 802.1AB LLDP                 01-80-C2-00-00-0E
247                  *
248                  * Others reserved for future standardization
249                  */
250                 fwd_mask |= p->group_fwd_mask;
251                 switch (dest[5]) {
252                 case 0x00:      /* Bridge Group Address */
253                         /* If STP is turned off,
254                            then must forward to keep loop detection */
255                         if (p->br->stp_enabled == BR_NO_STP ||
256                             fwd_mask & (1u << dest[5]))
257                                 goto forward;
258                         *pskb = skb;
259                         __br_handle_local_finish(skb);
260                         return RX_HANDLER_PASS;
261 
262                 case 0x01:      /* IEEE MAC (Pause) */
263                         goto drop;
264 
265                 case 0x0E:      /* 802.1AB LLDP */
266                         fwd_mask |= p->br->group_fwd_mask;
267                         if (fwd_mask & (1u << dest[5]))
268                                 goto forward;
269                         *pskb = skb;
270                         __br_handle_local_finish(skb);
271                         return RX_HANDLER_PASS;
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                 NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev),
282                         NULL, skb, skb->dev, NULL, br_handle_local_finish);
283                 return RX_HANDLER_CONSUMED;
284         }
285 
286 forward:
287         switch (p->state) {
288         case BR_STATE_FORWARDING:
289                 rhook = rcu_dereference(br_should_route_hook);
290                 if (rhook) {
291                         if ((*rhook)(skb)) {
292                                 *pskb = skb;
293                                 return RX_HANDLER_PASS;
294                         }
295                         dest = eth_hdr(skb)->h_dest;
296                 }
297                 /* fall through */
298         case BR_STATE_LEARNING:
299                 if (ether_addr_equal(p->br->dev->dev_addr, dest))
300                         skb->pkt_type = PACKET_HOST;
301 
302                 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
303                         dev_net(skb->dev), NULL, skb, skb->dev, NULL,
304                         br_handle_frame_finish);
305                 break;
306         default:
307 drop:
308                 kfree_skb(skb);
309         }
310         return RX_HANDLER_CONSUMED;
311 }
312 

~ [ 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