1/*
2 *	Forwarding decision
3 *	Linux ethernet bridge
4 *
5 *	Authors:
6 *	Lennert Buytenhek		<buytenh@gnu.org>
7 *
8 *	$Id: br_forward.c,v 1.1.1.1 2008/10/15 03:27:33 james26_jang 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/inetdevice.h>
19#include <linux/skbuff.h>
20#include <linux/if_bridge.h>
21#include <linux/netfilter_bridge.h>
22#include "br_private.h"
23
24static inline int should_deliver(struct net_bridge_port *p, struct sk_buff *skb)
25{
26	if (skb->dev == p->dev ||
27	    p->state != BR_STATE_FORWARDING)
28		return 0;
29
30	return 1;
31}
32
33static int __dev_queue_push_xmit(struct sk_buff *skb)
34{
35	skb_push(skb, ETH_HLEN);
36	dev_queue_xmit(skb);
37
38	return 0;
39}
40
41static int __br_forward_finish(struct sk_buff *skb)
42{
43	NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
44			__dev_queue_push_xmit);
45
46	return 0;
47}
48
49static void __br_deliver(struct net_bridge_port *to, struct sk_buff *skb)
50{
51	skb->dev = to->dev;
52	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
53			__br_forward_finish);
54}
55
56static void __br_forward(struct net_bridge_port *to, struct sk_buff *skb)
57{
58	struct net_device *indev;
59
60	indev = skb->dev;
61	skb->dev = to->dev;
62
63	NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
64			__br_forward_finish);
65}
66
67/* called under bridge lock */
68void br_deliver(struct net_bridge_port *to, struct sk_buff *skb)
69{
70	if (should_deliver(to, skb)) {
71		__br_deliver(to, skb);
72		return;
73	}
74
75	kfree_skb(skb);
76}
77
78/* called under bridge lock */
79void br_forward(struct net_bridge_port *to, struct sk_buff *skb)
80{
81	if (should_deliver(to, skb)) {
82		__br_forward(to, skb);
83		return;
84	}
85
86	kfree_skb(skb);
87}
88
89/* called under bridge lock */
90static void br_flood(struct net_bridge *br, struct sk_buff *skb, int clone,
91	void (*__packet_hook)(struct net_bridge_port *p, struct sk_buff *skb))
92{
93	struct net_bridge_port *p;
94	struct net_bridge_port *prev;
95
96	if (clone) {
97		struct sk_buff *skb2;
98
99		if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
100			br->statistics.tx_dropped++;
101			return;
102		}
103
104		skb = skb2;
105	}
106
107	prev = NULL;
108
109	p = br->port_list;
110	while (p != NULL) {
111		if (should_deliver(p, skb)) {
112			if (prev != NULL) {
113				struct sk_buff *skb2;
114
115				if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
116					br->statistics.tx_dropped++;
117					kfree_skb(skb);
118					return;
119				}
120
121				__packet_hook(prev, skb2);
122			}
123
124			prev = p;
125		}
126
127		p = p->next;
128	}
129
130	if (prev != NULL) {
131		__packet_hook(prev, skb);
132		return;
133	}
134
135	kfree_skb(skb);
136}
137
138/* called under bridge lock */
139void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, int clone)
140{
141	br_flood(br, skb, clone, __br_deliver);
142}
143
144/* called under bridge lock */
145void br_flood_forward(struct net_bridge *br, struct sk_buff *skb, int clone)
146{
147	br_flood(br, skb, clone, __br_forward);
148}
149