net: wireless: bcmdhd: Put p2p_dev_addr under DHD_P2P_DEV_ADDR_FROM_SYSFS
[linux-2.6.git] / net / ipv4 / ip_forward.c
1 /*
2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
3  *              operating system.  INET is implemented using the  BSD Socket
4  *              interface as the means of communication with the user level.
5  *
6  *              The IP forwarding functionality.
7  *
8  * Authors:     see ip.c
9  *
10  * Fixes:
11  *              Many            :       Split from ip.c , see ip_input.c for
12  *                                      history.
13  *              Dave Gregorich  :       NULL ip_rt_put fix for multicast
14  *                                      routing.
15  *              Jos Vos         :       Add call_out_firewall before sending,
16  *                                      use output device for accounting.
17  *              Jos Vos         :       Call forward firewall after routing
18  *                                      (always use output device).
19  *              Mike McLagan    :       Routing by source
20  */
21
22 #include <linux/types.h>
23 #include <linux/mm.h>
24 #include <linux/skbuff.h>
25 #include <linux/ip.h>
26 #include <linux/icmp.h>
27 #include <linux/netdevice.h>
28 #include <linux/slab.h>
29 #include <net/sock.h>
30 #include <net/ip.h>
31 #include <net/tcp.h>
32 #include <net/udp.h>
33 #include <net/icmp.h>
34 #include <linux/tcp.h>
35 #include <linux/udp.h>
36 #include <linux/netfilter_ipv4.h>
37 #include <net/checksum.h>
38 #include <linux/route.h>
39 #include <net/route.h>
40 #include <net/xfrm.h>
41
42 static int ip_forward_finish(struct sk_buff *skb)
43 {
44         struct ip_options * opt = &(IPCB(skb)->opt);
45
46         IP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), IPSTATS_MIB_OUTFORWDATAGRAMS);
47
48         if (unlikely(opt->optlen))
49                 ip_forward_options(skb);
50
51         return dst_output(skb);
52 }
53
54 int ip_forward(struct sk_buff *skb)
55 {
56         struct iphdr *iph;      /* Our header */
57         struct rtable *rt;      /* Route we use */
58         struct ip_options * opt = &(IPCB(skb)->opt);
59
60         if (skb_warn_if_lro(skb))
61                 goto drop;
62
63         if (!xfrm4_policy_check(NULL, XFRM_POLICY_FWD, skb))
64                 goto drop;
65
66         if (IPCB(skb)->opt.router_alert && ip_call_ra_chain(skb))
67                 return NET_RX_SUCCESS;
68
69         if (skb->pkt_type != PACKET_HOST)
70                 goto drop;
71
72         skb_forward_csum(skb);
73
74         /*
75          *      According to the RFC, we must first decrease the TTL field. If
76          *      that reaches zero, we must reply an ICMP control message telling
77          *      that the packet's lifetime expired.
78          */
79         if (ip_hdr(skb)->ttl <= 1)
80                 goto too_many_hops;
81
82         if (!xfrm4_route_forward(skb))
83                 goto drop;
84
85         rt = skb_rtable(skb);
86
87         if (opt->is_strictroute && ip_hdr(skb)->daddr != rt->rt_gateway)
88                 goto sr_failed;
89
90         if (unlikely(skb->len > dst_mtu(&rt->dst) && !skb_is_gso(skb) &&
91                      (ip_hdr(skb)->frag_off & htons(IP_DF))) && !skb->local_df) {
92                 IP_INC_STATS(dev_net(rt->dst.dev), IPSTATS_MIB_FRAGFAILS);
93                 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
94                           htonl(dst_mtu(&rt->dst)));
95                 goto drop;
96         }
97
98         /* We are about to mangle packet. Copy it! */
99         if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+rt->dst.header_len))
100                 goto drop;
101         iph = ip_hdr(skb);
102
103         /* Decrease ttl after skb cow done */
104         ip_decrease_ttl(iph);
105
106         /*
107          *      We now generate an ICMP HOST REDIRECT giving the route
108          *      we calculated.
109          */
110         if (rt->rt_flags&RTCF_DOREDIRECT && !opt->srr && !skb_sec_path(skb))
111                 ip_rt_send_redirect(skb);
112
113         skb->priority = rt_tos2priority(iph->tos);
114
115         return NF_HOOK(NFPROTO_IPV4, NF_INET_FORWARD, skb, skb->dev,
116                        rt->dst.dev, ip_forward_finish);
117
118 sr_failed:
119         /*
120          *      Strict routing permits no gatewaying
121          */
122          icmp_send(skb, ICMP_DEST_UNREACH, ICMP_SR_FAILED, 0);
123          goto drop;
124
125 too_many_hops:
126         /* Tell the sender its packet died... */
127         IP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), IPSTATS_MIB_INHDRERRORS);
128         icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0);
129 drop:
130         kfree_skb(skb);
131         return NET_RX_DROP;
132 }