1 /*
2 * Forwarding decision
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
8 * $Id: br_forward.c,v 1.4 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/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
should_deliver(struct net_bridge_port * p,struct sk_buff * skb)24 static 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
__dev_queue_push_xmit(struct sk_buff * skb)33 static 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
__br_forward_finish(struct sk_buff * skb)41 static 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
__br_deliver(struct net_bridge_port * to,struct sk_buff * skb)49 static 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
__br_forward(struct net_bridge_port * to,struct sk_buff * skb)56 static 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 skb->ip_summed = CHECKSUM_NONE;
63
64 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
65 __br_forward_finish);
66 }
67
68 /* called under bridge lock */
br_deliver(struct net_bridge_port * to,struct sk_buff * skb)69 void br_deliver(struct net_bridge_port *to, struct sk_buff *skb)
70 {
71 if (should_deliver(to, skb)) {
72 __br_deliver(to, skb);
73 return;
74 }
75
76 kfree_skb(skb);
77 }
78
79 /* called under bridge lock */
br_forward(struct net_bridge_port * to,struct sk_buff * skb)80 void br_forward(struct net_bridge_port *to, struct sk_buff *skb)
81 {
82 if (should_deliver(to, skb)) {
83 __br_forward(to, skb);
84 return;
85 }
86
87 kfree_skb(skb);
88 }
89
90 /* called under bridge lock */
br_flood(struct net_bridge * br,struct sk_buff * skb,int clone,void (* __packet_hook)(struct net_bridge_port * p,struct sk_buff * skb))91 static void br_flood(struct net_bridge *br, struct sk_buff *skb, int clone,
92 void (*__packet_hook)(struct net_bridge_port *p, struct sk_buff *skb))
93 {
94 struct net_bridge_port *p;
95 struct net_bridge_port *prev;
96
97 if (clone) {
98 struct sk_buff *skb2;
99
100 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
101 br->statistics.tx_dropped++;
102 return;
103 }
104
105 skb = skb2;
106 }
107
108 prev = NULL;
109
110 p = br->port_list;
111 while (p != NULL) {
112 if (should_deliver(p, skb)) {
113 if (prev != NULL) {
114 struct sk_buff *skb2;
115
116 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
117 br->statistics.tx_dropped++;
118 kfree_skb(skb);
119 return;
120 }
121
122 __packet_hook(prev, skb2);
123 }
124
125 prev = p;
126 }
127
128 p = p->next;
129 }
130
131 if (prev != NULL) {
132 __packet_hook(prev, skb);
133 return;
134 }
135
136 kfree_skb(skb);
137 }
138
139 /* called under bridge lock */
br_flood_deliver(struct net_bridge * br,struct sk_buff * skb,int clone)140 void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, int clone)
141 {
142 br_flood(br, skb, clone, __br_deliver);
143 }
144
145 /* called under bridge lock */
br_flood_forward(struct net_bridge * br,struct sk_buff * skb,int clone)146 void br_flood_forward(struct net_bridge *br, struct sk_buff *skb, int clone)
147 {
148 br_flood(br, skb, clone, __br_forward);
149 }
150