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 1.9.2.1 2001/12/24 04:50:05 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
br_pass_frame_up_finish(struct sk_buff * skb)25 static int br_pass_frame_up_finish(struct sk_buff *skb)
26 {
27 netif_rx(skb);
28
29 return 0;
30 }
31
br_pass_frame_up(struct net_bridge * br,struct sk_buff * skb)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
br_handle_frame_finish(struct sk_buff * skb)49 static int br_handle_frame_finish(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 if (p == NULL)
61 goto err_nolock;
62
63 br = p->br;
64 read_lock(&br->lock);
65 if (skb->dev->br_port == NULL)
66 goto err;
67
68 passedup = 0;
69 if (br->dev.flags & IFF_PROMISC) {
70 struct sk_buff *skb2;
71
72 skb2 = skb_clone(skb, GFP_ATOMIC);
73 if (skb2 != NULL) {
74 passedup = 1;
75 br_pass_frame_up(br, skb2);
76 }
77 }
78
79 if (dest[0] & 1) {
80 br_flood_forward(br, skb, !passedup);
81 if (!passedup)
82 br_pass_frame_up(br, skb);
83 goto out;
84 }
85
86 dst = br_fdb_get(br, dest);
87 if (dst != NULL && dst->is_local) {
88 if (!passedup)
89 br_pass_frame_up(br, skb);
90 else
91 kfree_skb(skb);
92 br_fdb_put(dst);
93 goto out;
94 }
95
96 if (dst != NULL) {
97 br_forward(dst->dst, skb);
98 br_fdb_put(dst);
99 goto out;
100 }
101
102 br_flood_forward(br, skb, 0);
103
104 out:
105 read_unlock(&br->lock);
106 return 0;
107
108 err:
109 read_unlock(&br->lock);
110 err_nolock:
111 kfree_skb(skb);
112 return 0;
113 }
114
br_handle_frame(struct sk_buff * skb)115 void br_handle_frame(struct sk_buff *skb)
116 {
117 struct net_bridge *br;
118 unsigned char *dest;
119 struct net_bridge_port *p;
120
121 dest = skb->mac.ethernet->h_dest;
122
123 p = skb->dev->br_port;
124 if (p == NULL)
125 goto err_nolock;
126
127 br = p->br;
128 read_lock(&br->lock);
129 if (skb->dev->br_port == NULL)
130 goto err;
131
132 if (!(br->dev.flags & IFF_UP) ||
133 p->state == BR_STATE_DISABLED)
134 goto err;
135
136 if (skb->mac.ethernet->h_source[0] & 1)
137 goto err;
138
139 if (p->state == BR_STATE_LEARNING ||
140 p->state == BR_STATE_FORWARDING)
141 br_fdb_insert(br, p, skb->mac.ethernet->h_source, 0);
142
143 if (br->stp_enabled &&
144 !memcmp(dest, bridge_ula, 5) &&
145 !(dest[5] & 0xF0))
146 goto handle_special_frame;
147
148 if (p->state == BR_STATE_FORWARDING) {
149 NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
150 br_handle_frame_finish);
151 read_unlock(&br->lock);
152 return;
153 }
154
155 err:
156 read_unlock(&br->lock);
157 err_nolock:
158 kfree_skb(skb);
159 return;
160
161 handle_special_frame:
162 if (!dest[5]) {
163 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,NULL,
164 br_stp_handle_bpdu);
165 read_unlock(&br->lock);
166 return;
167 }
168
169 read_unlock(&br->lock);
170 kfree_skb(skb);
171 }
172