1/*
2 *	Handle incoming frames
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/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"
20
21/* Bridge group multicast address 802.1d (pg 51). */
22const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
23
24int qos_enable = 0;		/* Foxconn added pling 03/13/2007 */
25static int br_pass_frame_up(struct sk_buff *skb)
26{
27	struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
28	struct net_bridge *br = netdev_priv(brdev);
29	struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats);
30
31	u64_stats_update_begin(&brstats->syncp);
32	brstats->rx_packets++;
33	brstats->rx_bytes += skb->len;
34	u64_stats_update_end(&brstats->syncp);
35
36	indev = skb->dev;
37	/* foxconn wklin added, 2010/06/15 @attach_dev */
38	if (htons(ETH_P_ARP) == eth_hdr(skb)->h_proto)
39	    *(pp_bridge_indev(skb)) = indev;/*backup incoming port to be used in arp.c */
40	skb->dev = brdev;
41
42	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
43		       netif_receive_skb);
44}
45
46/* note: already called with rcu_read_lock */
47int br_handle_frame_finish(struct sk_buff *skb)
48{
49	const unsigned char *dest = eth_hdr(skb)->h_dest;
50	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
51	struct net_bridge *br;
52	struct net_bridge_fdb_entry *dst;
53	struct net_bridge_mdb_entry *mdst;
54	struct sk_buff *skb2;
55
56	if (!p || p->state == BR_STATE_DISABLED)
57		goto drop;
58
59	/* insert into forwarding database after filtering to avoid spoofing */
60	br = p->br;
61#ifdef HNDCTF
62	br_fdb_update(br, p, eth_hdr(skb)->h_source, skb);
63#else
64	br_fdb_update(br, p, eth_hdr(skb)->h_source);
65#endif
66
67	if (is_multicast_ether_addr(dest) &&
68	    br_multicast_rcv(br, p, skb))
69		goto drop;
70
71	if (p->state == BR_STATE_LEARNING)
72		goto drop;
73
74	BR_INPUT_SKB_CB(skb)->brdev = br->dev;
75
76	/* The packet skb2 goes to the local host (NULL to skip). */
77	skb2 = NULL;
78
79	if (br->dev->flags & IFF_PROMISC)
80		skb2 = skb;
81
82	dst = NULL;
83
84	if (is_multicast_ether_addr(dest)) {
85		mdst = br_mdb_get(br, skb);
86		if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) {
87			if ((mdst && mdst->mglist) ||
88			    br_multicast_is_router(br))
89				skb2 = skb;
90			br_multicast_forward(mdst, skb, skb2);
91			skb = NULL;
92			if (!skb2)
93				goto out;
94		} else
95			skb2 = skb;
96
97		br->dev->stats.multicast++;
98	} else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) {
99		skb2 = skb;
100		/* Do not forward the packet since it's local. */
101		skb = NULL;
102	}
103
104	if (skb) {
105		if (dst)
106			br_forward(dst->dst, skb, skb2);
107		else
108			br_flood_forward(br, skb, skb2);
109	}
110
111	if (skb2)
112		return br_pass_frame_up(skb2);
113
114out:
115	return 0;
116drop:
117	kfree_skb(skb);
118	goto out;
119}
120
121/* note: already called with rcu_read_lock */
122static int br_handle_local_finish(struct sk_buff *skb)
123{
124	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
125
126#ifdef HNDCTF
127	br_fdb_update(p->br, p, eth_hdr(skb)->h_source, skb);
128#else
129	br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
130#endif
131	return 0;	 /* process further */
132}
133
134/* Does address match the link local multicast address.
135 * 01:80:c2:00:00:0X
136 */
137static inline int is_link_local(const unsigned char *dest)
138{
139	__be16 *a = (__be16 *)dest;
140	static const __be16 *b = (const __be16 *)br_group_address;
141	static const __be16 m = cpu_to_be16(0xfff0);
142
143	return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
144}
145
146/*
147 * Return NULL if skb is handled
148 * note: already called with rcu_read_lock
149 */
150struct sk_buff *br_handle_frame(struct sk_buff *skb)
151{
152	struct net_bridge_port *p;
153	const unsigned char *dest = eth_hdr(skb)->h_dest;
154	int (*rhook)(struct sk_buff *skb);
155
156	if (skb->pkt_type == PACKET_LOOPBACK)
157		return skb;
158
159	if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
160		goto drop;
161
162	skb = skb_share_check(skb, GFP_ATOMIC);
163	if (!skb)
164		return NULL;
165
166	p = br_port_get_rcu(skb->dev);
167
168	if (unlikely(is_link_local(dest))) {
169		/* Pause frames shouldn't be passed up by driver anyway */
170		if (skb->protocol == htons(ETH_P_PAUSE))
171			goto drop;
172
173		/* If STP is turned off, then forward */
174		if (p->br->stp_enabled == BR_NO_STP && dest[5] == 0)
175			goto forward;
176
177		if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
178			    NULL, br_handle_local_finish))
179			return NULL;	/* frame consumed by filter */
180		else
181			return skb;	/* continue processing */
182	}
183
184forward:
185	switch (p->state) {
186	case BR_STATE_FORWARDING:
187		rhook = rcu_dereference(br_should_route_hook);
188		if (rhook != NULL) {
189			if (rhook(skb))
190				return skb;
191			dest = eth_hdr(skb)->h_dest;
192		}
193		/* fall through */
194	case BR_STATE_LEARNING:
195		if (!compare_ether_addr(p->br->dev->dev_addr, dest))
196			skb->pkt_type = PACKET_HOST;
197
198		NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
199			br_handle_frame_finish);
200		break;
201	default:
202drop:
203		kfree_skb(skb);
204	}
205	return NULL;
206}
207