summaryrefslogtreecommitdiffstats
path: root/net/bridge/br_input.c
blob: 4eef837553153df523fc1053d04ac07e55cfd4e3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
/*
 *	Handle incoming frames
 *	Linux ethernet bridge
 *
 *	Authors:
 *	Lennert Buytenhek		<buytenh@gnu.org>
 *
 *	$Id: br_input.c,v 1.10 2001/12/24 04:50:20 davem Exp $
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/netfilter_bridge.h>
#include "br_private.h"

const unsigned char bridge_ula[6] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };

static int br_pass_frame_up_finish(struct sk_buff *skb)
{
	netif_receive_skb(skb);
	return 0;
}

static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb)
{
	struct net_device *indev;

	br->statistics.rx_packets++;
	br->statistics.rx_bytes += skb->len;

	indev = skb->dev;
	skb->dev = br->dev;

	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
			br_pass_frame_up_finish);
}

/* note: already called with rcu_read_lock (preempt_disabled) */
int br_handle_frame_finish(struct sk_buff *skb)
{
	const unsigned char *dest = eth_hdr(skb)->h_dest;
	struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
	struct net_bridge *br;
	struct net_bridge_fdb_entry *dst;
	int passedup = 0;

	if (!p || p->state == BR_STATE_DISABLED)
		goto drop;

	/* insert into forwarding database after filtering to avoid spoofing */
	br = p->br;
	br_fdb_update(br, p, eth_hdr(skb)->h_source);

	if (p->state == BR_STATE_LEARNING)
		goto drop;

	if (br->dev->flags & IFF_PROMISC) {
		struct sk_buff *skb2;

		skb2 = skb_clone(skb, GFP_ATOMIC);
		if (skb2 != NULL) {
			passedup = 1;
			br_pass_frame_up(br, skb2);
		}
	}

	if (is_multicast_ether_addr(dest)) {
		br_flood_forward(br, skb, !passedup);
		if (!passedup)
			br_pass_frame_up(br, skb);
		goto out;
	}

	dst = __br_fdb_get(br, dest);
	if (dst != NULL && dst->is_local) {
		if (!passedup)
			br_pass_frame_up(br, skb);
		else
			kfree_skb(skb);
		goto out;
	}

	if (dst != NULL) {
		br_forward(dst->dst, skb);
		goto out;
	}

	br_flood_forward(br, skb, 0);

out:
	return 0;
drop:
	kfree_skb(skb);
	goto out;
}

/*
 * Called via br_handle_frame_hook.
 * Return 0 if *pskb should be processed furthur
 *	  1 if *pskb is handled
 * note: already called with rcu_read_lock (preempt_disabled) 
 */
int br_handle_frame(struct net_bridge_port *p, struct sk_buff **pskb)
{
	struct sk_buff *skb = *pskb;
	const unsigned char *dest = eth_hdr(skb)->h_dest;

	if (p->state == BR_STATE_DISABLED)
		goto err;

	if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
		goto err;

	if (p->br->stp_enabled &&
	    !memcmp(dest, bridge_ula, 5) &&
	    !(dest[5] & 0xF0)) {
		if (!dest[5]) {
			NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, 
				NULL, br_stp_handle_bpdu);
			return 1;
		}
		goto err;
	}

	if (p->state == BR_STATE_FORWARDING || p->state == BR_STATE_LEARNING) {
		if (br_should_route_hook) {
			if (br_should_route_hook(pskb)) 
				return 0;
			skb = *pskb;
			dest = eth_hdr(skb)->h_dest;
		}

		if (!compare_ether_addr(p->br->dev->dev_addr, dest))
			skb->pkt_type = PACKET_HOST;

		NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
			br_handle_frame_finish);
		return 1;
	}

err:
	kfree_skb(skb);
	return 1;
}