2 * Handle incoming frames
3 * Linux ethernet bridge
6 * Lennert Buytenhek <buytenh@gnu.org>
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.
14 #include <linux/slab.h>
15 #include <linux/kernel.h>
16 #include <linux/netdevice.h>
17 #include <linux/etherdevice.h>
18 #include <linux/netfilter_bridge.h>
19 #include "br_private.h"
21 /* Bridge group multicast address 802.1d (pg 51). */
22 const u8 br_group_address
[ETH_ALEN
] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
24 static int br_pass_frame_up(struct sk_buff
*skb
)
26 struct net_device
*indev
, *brdev
= BR_INPUT_SKB_CB(skb
)->brdev
;
28 brdev
->stats
.rx_packets
++;
29 brdev
->stats
.rx_bytes
+= skb
->len
;
34 return NF_HOOK(PF_BRIDGE
, NF_BR_LOCAL_IN
, skb
, indev
, NULL
,
38 /* note: already called with rcu_read_lock (preempt_disabled) */
39 int br_handle_frame_finish(struct sk_buff
*skb
)
41 const unsigned char *dest
= eth_hdr(skb
)->h_dest
;
42 struct net_bridge_port
*p
= rcu_dereference(skb
->dev
->br_port
);
43 struct net_bridge
*br
;
44 struct net_bridge_fdb_entry
*dst
;
45 struct net_bridge_mdb_entry
*mdst
;
48 if (!p
|| p
->state
== BR_STATE_DISABLED
)
51 /* insert into forwarding database after filtering to avoid spoofing */
53 br_fdb_update(br
, p
, eth_hdr(skb
)->h_source
);
55 if (is_multicast_ether_addr(dest
) &&
56 br_multicast_rcv(br
, p
, skb
))
59 if (p
->state
== BR_STATE_LEARNING
)
62 BR_INPUT_SKB_CB(skb
)->brdev
= br
->dev
;
64 /* The packet skb2 goes to the local host (NULL to skip). */
67 if (br
->dev
->flags
& IFF_PROMISC
)
72 if (is_multicast_ether_addr(dest
)) {
73 mdst
= br_mdb_get(br
, skb
);
74 if (mdst
|| BR_INPUT_SKB_CB_MROUTERS_ONLY(skb
)) {
75 if ((mdst
&& !hlist_unhashed(&mdst
->mglist
)) ||
76 br_multicast_is_router(br
))
78 br_multicast_forward(mdst
, skb
, skb2
);
85 br
->dev
->stats
.multicast
++;
86 } else if ((dst
= __br_fdb_get(br
, dest
)) && dst
->is_local
) {
88 /* Do not forward the packet since it's local. */
94 br_forward(dst
->dst
, skb
, skb2
);
96 br_flood_forward(br
, skb
, skb2
);
100 return br_pass_frame_up(skb2
);
109 /* note: already called with rcu_read_lock (preempt_disabled) */
110 static int br_handle_local_finish(struct sk_buff
*skb
)
112 struct net_bridge_port
*p
= rcu_dereference(skb
->dev
->br_port
);
115 br_fdb_update(p
->br
, p
, eth_hdr(skb
)->h_source
);
116 return 0; /* process further */
119 /* Does address match the link local multicast address.
122 static inline int is_link_local(const unsigned char *dest
)
124 __be16
*a
= (__be16
*)dest
;
125 static const __be16
*b
= (const __be16
*)br_group_address
;
126 static const __be16 m
= cpu_to_be16(0xfff0);
128 return ((a
[0] ^ b
[0]) | (a
[1] ^ b
[1]) | ((a
[2] ^ b
[2]) & m
)) == 0;
132 * Called via br_handle_frame_hook.
133 * Return NULL if skb is handled
134 * note: already called with rcu_read_lock (preempt_disabled)
136 struct sk_buff
*br_handle_frame(struct net_bridge_port
*p
, struct sk_buff
*skb
)
138 const unsigned char *dest
= eth_hdr(skb
)->h_dest
;
139 int (*rhook
)(struct sk_buff
*skb
);
141 if (!is_valid_ether_addr(eth_hdr(skb
)->h_source
))
144 skb
= skb_share_check(skb
, GFP_ATOMIC
);
148 if (unlikely(is_link_local(dest
))) {
149 /* Pause frames shouldn't be passed up by driver anyway */
150 if (skb
->protocol
== htons(ETH_P_PAUSE
))
153 /* If STP is turned off, then forward */
154 if (p
->br
->stp_enabled
== BR_NO_STP
&& dest
[5] == 0)
157 if (NF_HOOK(PF_BRIDGE
, NF_BR_LOCAL_IN
, skb
, skb
->dev
,
158 NULL
, br_handle_local_finish
))
159 return NULL
; /* frame consumed by filter */
161 return skb
; /* continue processing */
166 case BR_STATE_FORWARDING
:
167 rhook
= rcu_dereference(br_should_route_hook
);
171 dest
= eth_hdr(skb
)->h_dest
;
174 case BR_STATE_LEARNING
:
175 if (!compare_ether_addr(p
->br
->dev
->dev_addr
, dest
))
176 skb
->pkt_type
= PACKET_HOST
;
178 NF_HOOK(PF_BRIDGE
, NF_BR_PRE_ROUTING
, skb
, skb
->dev
, NULL
,
179 br_handle_frame_finish
);