tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 */
22static inline int should_deliver(const struct net_bridge_port *p,
23 const struct sk_buff *skb)
24{
25 return (skb->dev != p->dev && p->state == BR_STATE_FORWARDING);
26}
27
28static inline unsigned packet_length(const struct sk_buff *skb)
29{
30 return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
31}
32
33int br_dev_queue_push_xmit(struct sk_buff *skb)
34{
35 /* drop mtu oversized packets except gso */
36 if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
37 kfree_skb(skb);
38 else {
39 /* ip_refrag calls ip_fragment, doesn't copy the MAC header. */
40 if (nf_bridge_maybe_copy_header(skb))
41 kfree_skb(skb);
42 else {
43 skb_push(skb, ETH_HLEN);
44
45 dev_queue_xmit(skb);
46 }
47 }
48
49 return 0;
50}
51
52int br_forward_finish(struct sk_buff *skb)
53{
54 return NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
55 br_dev_queue_push_xmit);
56
57}
58
59static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
60{
61 skb->dev = to->dev;
62 NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
63 br_forward_finish);
64}
65
66static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
67{
68 struct net_device *indev;
69
70 indev = skb->dev;
71 skb->dev = to->dev;
72 skb_forward_csum(skb);
73
74 NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
75 br_forward_finish);
76}
77
78/* called with rcu_read_lock */
79void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
80{
81 if (should_deliver(to, skb)) {
82 __br_deliver(to, skb);
83 return;
84 }
85
86 kfree_skb(skb);
87}
88
89/* called with rcu_read_lock */
90void br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
91{
92 if (!skb_warn_if_lro(skb) && should_deliver(to, skb)) {
93 __br_forward(to, skb);
94 return;
95 }
96
97 kfree_skb(skb);
98}
99
100/* called under bridge lock */
101static void br_flood(struct net_bridge *br, struct sk_buff *skb,
102 void (*__packet_hook)(const struct net_bridge_port *p,
103 struct sk_buff *skb))
104{
105 struct net_bridge_port *p;
106 struct net_bridge_port *prev;
107
108 prev = NULL;
109
110 list_for_each_entry_rcu(p, &br->port_list, list) {
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->dev->stats.tx_dropped++;
117 kfree_skb(skb);
118 return;
119 }
120
121 __packet_hook(prev, skb2);
122 }
123
124 prev = p;
125 }
126 }
127
128 if (prev != NULL) {
129 __packet_hook(prev, skb);
130 return;
131 }
132
133 kfree_skb(skb);
134}
135
136
137/* called with rcu_read_lock */
138void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb)
139{
140 br_flood(br, skb, __br_deliver);
141}
142
143/* called under bridge lock */
144void br_flood_forward(struct net_bridge *br, struct sk_buff *skb)
145{
146 br_flood(br, skb, __br_forward);
147}