File: /usr/src/linux/net/bridge/br_input.c
1 /*
2 * Handle incoming frames
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
8 * $Id: br_input.c,v 1.9 2001/08/14 22:05:57 davem Exp $
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/netdevice.h>
18 #include <linux/etherdevice.h>
19 #include <linux/if_bridge.h>
20 #include <linux/netfilter_bridge.h>
21 #include "br_private.h"
22
23 unsigned char bridge_ula[6] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
24
25 static int br_pass_frame_up_finish(struct sk_buff *skb)
26 {
27 netif_rx(skb);
28
29 return 0;
30 }
31
32 static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb)
33 {
34 struct net_device *indev;
35
36 br->statistics.rx_packets++;
37 br->statistics.rx_bytes += skb->len;
38
39 indev = skb->dev;
40 skb->dev = &br->dev;
41 skb->pkt_type = PACKET_HOST;
42 skb_push(skb, ETH_HLEN);
43 skb->protocol = eth_type_trans(skb, &br->dev);
44
45 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
46 br_pass_frame_up_finish);
47 }
48
49 static void __br_handle_frame(struct sk_buff *skb)
50 {
51 struct net_bridge *br;
52 unsigned char *dest;
53 struct net_bridge_fdb_entry *dst;
54 struct net_bridge_port *p;
55 int passedup;
56
57 dest = skb->mac.ethernet->h_dest;
58
59 p = skb->dev->br_port;
60 br = p->br;
61 passedup = 0;
62
63 if (!(br->dev.flags & IFF_UP) ||
64 p->state == BR_STATE_DISABLED)
65 goto freeandout;
66
67 if (br->dev.flags & IFF_PROMISC) {
68 struct sk_buff *skb2;
69
70 skb2 = skb_clone(skb, GFP_ATOMIC);
71 if (skb2) {
72 passedup = 1;
73 br_pass_frame_up(br, skb2);
74 }
75 }
76
77 if (skb->mac.ethernet->h_source[0] & 1)
78 goto freeandout;
79
80 if (!passedup &&
81 (dest[0] & 1) &&
82 (br->dev.flags & IFF_ALLMULTI || br->dev.mc_list != NULL)) {
83 struct sk_buff *skb2;
84
85 skb2 = skb_clone(skb, GFP_ATOMIC);
86 if (skb2) {
87 passedup = 1;
88 br_pass_frame_up(br, skb2);
89 }
90 }
91
92 if (br->stp_enabled &&
93 !memcmp(dest, bridge_ula, 5) &&
94 !(dest[5] & 0xF0))
95 goto handle_special_frame;
96
97 if (p->state == BR_STATE_LEARNING ||
98 p->state == BR_STATE_FORWARDING)
99 br_fdb_insert(br, p, skb->mac.ethernet->h_source, 0);
100
101 if (p->state != BR_STATE_FORWARDING)
102 goto freeandout;
103
104 if (dest[0] & 1) {
105 br_flood_forward(br, skb, 1);
106 if (!passedup)
107 br_pass_frame_up(br, skb);
108 else
109 kfree_skb(skb);
110 return;
111 }
112
113 dst = br_fdb_get(br, dest);
114
115 if (dst != NULL && dst->is_local) {
116 if (!passedup)
117 br_pass_frame_up(br, skb);
118 else
119 kfree_skb(skb);
120 br_fdb_put(dst);
121 return;
122 }
123
124 if (dst != NULL) {
125 br_forward(dst->dst, skb);
126 br_fdb_put(dst);
127 return;
128 }
129
130 br_flood_forward(br, skb, 0);
131 return;
132
133 handle_special_frame:
134 if (!dest[5]) {
135 br_stp_handle_bpdu(skb);
136 return;
137 }
138
139 freeandout:
140 kfree_skb(skb);
141 }
142
143 static int br_handle_frame_finish(struct sk_buff *skb)
144 {
145 struct net_bridge *br;
146
147 br = skb->dev->br_port->br;
148 read_lock(&br->lock);
149 __br_handle_frame(skb);
150 read_unlock(&br->lock);
151
152 return 0;
153 }
154
155 void br_handle_frame(struct sk_buff *skb)
156 {
157 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
158 br_handle_frame_finish);
159 }
160