1 // SPDX-License-Identifier: GPL-2.0-or-later
4 * Linux ethernet bridge
7 * Lennert Buytenhek <buytenh@gnu.org>
8 * Bart De Schuymer <bdschuym@pandora.be>
10 * Lennert dedicates this file to Kerstin Wurdinger.
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
17 #include <linux/netdevice.h>
18 #include <linux/skbuff.h>
19 #include <linux/if_arp.h>
20 #include <linux/if_ether.h>
21 #include <linux/if_vlan.h>
22 #include <linux/if_pppox.h>
23 #include <linux/ppp_defs.h>
24 #include <linux/netfilter_bridge.h>
25 #include <linux/netfilter_ipv4.h>
26 #include <linux/netfilter_ipv6.h>
27 #include <linux/netfilter_arp.h>
28 #include <linux/in_route.h>
29 #include <linux/inetdevice.h>
33 #include <net/addrconf.h>
34 #include <net/route.h>
35 #include <net/netfilter/br_netfilter.h>
37 #include <linux/uaccess.h>
38 #include "br_private.h"
40 #include <linux/sysctl.h>
43 /* We only check the length. A bridge shouldn't do any hop-by-hop stuff
46 static int br_nf_check_hbh_len(struct sk_buff
*skb
)
48 unsigned char *raw
= (u8
*)(ipv6_hdr(skb
) + 1);
50 const unsigned char *nh
= skb_network_header(skb
);
52 int len
= (raw
[1] + 1) << 3;
54 if ((raw
+ len
) - skb
->data
> skb_headlen(skb
))
61 int optlen
= nh
[off
+ 1] + 2;
72 if (nh
[off
+ 1] != 4 || (off
& 3) != 2)
74 pkt_len
= ntohl(*(__be32
*)(nh
+ off
+ 2));
75 if (pkt_len
<= IPV6_MAXPLEN
||
76 ipv6_hdr(skb
)->payload_len
)
78 if (pkt_len
> skb
->len
- sizeof(struct ipv6hdr
))
80 if (pskb_trim_rcsum(skb
,
81 pkt_len
+ sizeof(struct ipv6hdr
)))
83 nh
= skb_network_header(skb
);
99 int br_validate_ipv6(struct net
*net
, struct sk_buff
*skb
)
101 const struct ipv6hdr
*hdr
;
102 struct inet6_dev
*idev
= __in6_dev_get(skb
->dev
);
104 u8 ip6h_len
= sizeof(struct ipv6hdr
);
106 if (!pskb_may_pull(skb
, ip6h_len
))
109 if (skb
->len
< ip6h_len
)
114 if (hdr
->version
!= 6)
117 pkt_len
= ntohs(hdr
->payload_len
);
119 if (pkt_len
|| hdr
->nexthdr
!= NEXTHDR_HOP
) {
120 if (pkt_len
+ ip6h_len
> skb
->len
) {
121 __IP6_INC_STATS(net
, idev
,
122 IPSTATS_MIB_INTRUNCATEDPKTS
);
125 if (pskb_trim_rcsum(skb
, pkt_len
+ ip6h_len
)) {
126 __IP6_INC_STATS(net
, idev
,
127 IPSTATS_MIB_INDISCARDS
);
132 if (hdr
->nexthdr
== NEXTHDR_HOP
&& br_nf_check_hbh_len(skb
))
135 memset(IP6CB(skb
), 0, sizeof(struct inet6_skb_parm
));
136 /* No IP options in IPv6 header; however it should be
137 * checked if some next headers need special treatment
142 __IP6_INC_STATS(net
, idev
, IPSTATS_MIB_INHDRERRORS
);
148 br_nf_ipv6_daddr_was_changed(const struct sk_buff
*skb
,
149 const struct nf_bridge_info
*nf_bridge
)
151 return memcmp(&nf_bridge
->ipv6_daddr
, &ipv6_hdr(skb
)->daddr
,
152 sizeof(ipv6_hdr(skb
)->daddr
)) != 0;
155 /* PF_BRIDGE/PRE_ROUTING: Undo the changes made for ip6tables
156 * PREROUTING and continue the bridge PRE_ROUTING hook. See comment
157 * for br_nf_pre_routing_finish(), same logic is used here but
158 * equivalent IPv6 function ip6_route_input() called indirectly.
160 static int br_nf_pre_routing_finish_ipv6(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
162 struct nf_bridge_info
*nf_bridge
= nf_bridge_info_get(skb
);
164 struct net_device
*dev
= skb
->dev
;
165 const struct nf_ipv6_ops
*v6ops
= nf_get_ipv6_ops();
167 nf_bridge
->frag_max_size
= IP6CB(skb
)->frag_max_size
;
169 if (nf_bridge
->pkt_otherhost
) {
170 skb
->pkt_type
= PACKET_OTHERHOST
;
171 nf_bridge
->pkt_otherhost
= false;
173 nf_bridge
->in_prerouting
= 0;
174 if (br_nf_ipv6_daddr_was_changed(skb
, nf_bridge
)) {
176 v6ops
->route_input(skb
);
178 if (skb_dst(skb
)->error
) {
183 if (skb_dst(skb
)->dev
== dev
) {
184 skb
->dev
= nf_bridge
->physindev
;
185 nf_bridge_update_protocol(skb
);
186 nf_bridge_push_encap_header(skb
);
187 br_nf_hook_thresh(NF_BR_PRE_ROUTING
,
188 net
, sk
, skb
, skb
->dev
, NULL
,
189 br_nf_pre_routing_finish_bridge
);
192 ether_addr_copy(eth_hdr(skb
)->h_dest
, dev
->dev_addr
);
193 skb
->pkt_type
= PACKET_HOST
;
195 rt
= bridge_parent_rtable(nf_bridge
->physindev
);
200 skb_dst_set_noref(skb
, &rt
->dst
);
203 skb
->dev
= nf_bridge
->physindev
;
204 nf_bridge_update_protocol(skb
);
205 nf_bridge_push_encap_header(skb
);
206 br_nf_hook_thresh(NF_BR_PRE_ROUTING
, net
, sk
, skb
,
207 skb
->dev
, NULL
, br_handle_frame_finish
);
212 /* Replicate the checks that IPv6 does on packet reception and pass the packet
215 unsigned int br_nf_pre_routing_ipv6(void *priv
,
217 const struct nf_hook_state
*state
)
219 struct nf_bridge_info
*nf_bridge
;
221 if (br_validate_ipv6(state
->net
, skb
))
224 nf_bridge
= nf_bridge_alloc(skb
);
227 if (!setup_pre_routing(skb
, state
->net
))
230 nf_bridge
= nf_bridge_info_get(skb
);
231 nf_bridge
->ipv6_daddr
= ipv6_hdr(skb
)->daddr
;
233 skb
->protocol
= htons(ETH_P_IPV6
);
234 skb
->transport_header
= skb
->network_header
+ sizeof(struct ipv6hdr
);
236 NF_HOOK(NFPROTO_IPV6
, NF_INET_PRE_ROUTING
, state
->net
, state
->sk
, skb
,
238 br_nf_pre_routing_finish_ipv6
);