netfilter: xtables: add struct xt_mtdtor_param::net
[linux-2.6.git] / net / bridge / br_forward.c
1 /*
2  *      Forwarding decision
3  *      Linux ethernet bridge
4  *
5  *      Authors:
6  *      Lennert Buytenhek               <buytenh@gnu.org>
7  *
8  *      This program is free software; you can redistribute it and/or
9  *      modify it under the terms of the GNU General Public License
10  *      as published by the Free Software Foundation; either version
11  *      2 of the License, or (at your option) any later version.
12  */
13
14 #include <linux/kernel.h>
15 #include <linux/netdevice.h>
16 #include <linux/skbuff.h>
17 #include <linux/if_vlan.h>
18 #include <linux/netfilter_bridge.h>
19 #include "br_private.h"
20
21 /* Don't forward packets to originating port or forwarding diasabled */
22 static inline int should_deliver(const struct net_bridge_port *p,
23                                  const struct sk_buff *skb)
24 {
25         return (((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
26                 p->state == BR_STATE_FORWARDING);
27 }
28
29 static inline unsigned packet_length(const struct sk_buff *skb)
30 {
31         return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
32 }
33
34 int br_dev_queue_push_xmit(struct sk_buff *skb)
35 {
36         /* drop mtu oversized packets except gso */
37         if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
38                 kfree_skb(skb);
39         else {
40                 /* ip_refrag calls ip_fragment, doesn't copy the MAC header. */
41                 if (nf_bridge_maybe_copy_header(skb))
42                         kfree_skb(skb);
43                 else {
44                         skb_push(skb, ETH_HLEN);
45
46                         dev_queue_xmit(skb);
47                 }
48         }
49
50         return 0;
51 }
52
53 int br_forward_finish(struct sk_buff *skb)
54 {
55         return NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
56                        br_dev_queue_push_xmit);
57
58 }
59
60 static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
61 {
62         skb->dev = to->dev;
63         NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
64                         br_forward_finish);
65 }
66
67 static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
68 {
69         struct net_device *indev;
70
71         if (skb_warn_if_lro(skb)) {
72                 kfree_skb(skb);
73                 return;
74         }
75
76         indev = skb->dev;
77         skb->dev = to->dev;
78         skb_forward_csum(skb);
79
80         NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
81                         br_forward_finish);
82 }
83
84 /* called with rcu_read_lock */
85 void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
86 {
87         if (should_deliver(to, skb)) {
88                 __br_deliver(to, skb);
89                 return;
90         }
91
92         kfree_skb(skb);
93 }
94
95 /* called with rcu_read_lock */
96 void br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
97 {
98         if (should_deliver(to, skb)) {
99                 __br_forward(to, skb);
100                 return;
101         }
102
103         kfree_skb(skb);
104 }
105
106 /* called under bridge lock */
107 static void br_flood(struct net_bridge *br, struct sk_buff *skb,
108         void (*__packet_hook)(const struct net_bridge_port *p,
109                               struct sk_buff *skb))
110 {
111         struct net_bridge_port *p;
112         struct net_bridge_port *prev;
113
114         prev = NULL;
115
116         list_for_each_entry_rcu(p, &br->port_list, list) {
117                 if (should_deliver(p, skb)) {
118                         if (prev != NULL) {
119                                 struct sk_buff *skb2;
120
121                                 if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
122                                         br->dev->stats.tx_dropped++;
123                                         kfree_skb(skb);
124                                         return;
125                                 }
126
127                                 __packet_hook(prev, skb2);
128                         }
129
130                         prev = p;
131                 }
132         }
133
134         if (prev != NULL) {
135                 __packet_hook(prev, skb);
136                 return;
137         }
138
139         kfree_skb(skb);
140 }
141
142
143 /* called with rcu_read_lock */
144 void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb)
145 {
146         br_flood(br, skb, __br_deliver);
147 }
148
149 /* called under bridge lock */
150 void br_flood_forward(struct net_bridge *br, struct sk_buff *skb)
151 {
152         br_flood(br, skb, __br_forward);
153 }