2 * Handle incoming frames
3 * Linux ethernet bridge
6 * Lennert Buytenhek <buytenh@gnu.org>
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.
14 #include <linux/kernel.h>
15 #include <linux/netdevice.h>
16 #include <linux/etherdevice.h>
17 #include <linux/netfilter_bridge.h>
18 #include "br_private.h"
20 /* Bridge group multicast address 802.1d (pg 51). */
21 const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
23 static int br_pass_frame_up(struct sk_buff *skb)
25 struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
26 struct net_bridge *br = netdev_priv(brdev);
27 struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats);
29 brstats->rx_packets++;
30 brstats->rx_bytes += skb->len;
35 return NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
39 /* note: already called with rcu_read_lock (preempt_disabled) */
40 int br_handle_frame_finish(struct sk_buff *skb)
42 const unsigned char *dest = eth_hdr(skb)->h_dest;
43 struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
44 struct net_bridge *br;
45 struct net_bridge_fdb_entry *dst;
46 struct net_bridge_mdb_entry *mdst;
49 if (!p || p->state == BR_STATE_DISABLED)
52 /* insert into forwarding database after filtering to avoid spoofing */
54 br_fdb_update(br, p, eth_hdr(skb)->h_source);
56 if (is_multicast_ether_addr(dest) &&
57 br_multicast_rcv(br, p, skb))
60 if (p->state == BR_STATE_LEARNING)
63 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
65 /* The packet skb2 goes to the local host (NULL to skip). */
68 if (br->dev->flags & IFF_PROMISC)
73 if (is_multicast_ether_addr(dest)) {
74 mdst = br_mdb_get(br, skb);
75 if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) {
76 if ((mdst && !hlist_unhashed(&mdst->mglist)) ||
77 br_multicast_is_router(br))
79 br_multicast_forward(mdst, skb, skb2);
86 br->dev->stats.multicast++;
87 } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) {
89 /* Do not forward the packet since it's local. */
95 br_forward(dst->dst, skb, skb2);
97 br_flood_forward(br, skb, skb2);
101 return br_pass_frame_up(skb2);
110 /* note: already called with rcu_read_lock (preempt_disabled) */
111 static int br_handle_local_finish(struct sk_buff *skb)
113 struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
116 br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
117 return 0; /* process further */
120 /* Does address match the link local multicast address.
123 static inline int is_link_local(const unsigned char *dest)
125 __be16 *a = (__be16 *)dest;
126 static const __be16 *b = (const __be16 *)br_group_address;
127 static const __be16 m = cpu_to_be16(0xfff0);
129 return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
133 * Called via br_handle_frame_hook.
134 * Return NULL if skb is handled
135 * note: already called with rcu_read_lock (preempt_disabled)
137 struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb)
139 const unsigned char *dest = eth_hdr(skb)->h_dest;
140 int (*rhook)(struct sk_buff *skb);
142 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
145 skb = skb_share_check(skb, GFP_ATOMIC);
149 if (unlikely(is_link_local(dest))) {
150 /* Pause frames shouldn't be passed up by driver anyway */
151 if (skb->protocol == htons(ETH_P_PAUSE))
154 /* If STP is turned off, then forward */
155 if (p->br->stp_enabled == BR_NO_STP && dest[5] == 0)
158 if (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
159 NULL, br_handle_local_finish))
160 return NULL; /* frame consumed by filter */
162 return skb; /* continue processing */
167 case BR_STATE_FORWARDING:
168 rhook = rcu_dereference(br_should_route_hook);
172 dest = eth_hdr(skb)->h_dest;
175 case BR_STATE_LEARNING:
176 if (!compare_ether_addr(p->br->dev->dev_addr, dest))
177 skb->pkt_type = PACKET_HOST;
179 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
180 br_handle_frame_finish);