Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 1 | /* IPv4 specific functions of netfilter core */ |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 2 | #include <linux/kernel.h> |
| 3 | #include <linux/netfilter.h> |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 4 | #include <linux/netfilter_ipv4.h> |
Patrick McHardy | 3e3850e | 2006-01-06 23:04:54 -0800 | [diff] [blame] | 5 | #include <linux/ip.h> |
Herbert Xu | 2ca7b0a | 2007-10-14 00:39:55 -0700 | [diff] [blame] | 6 | #include <linux/skbuff.h> |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 7 | #include <net/route.h> |
Patrick McHardy | 3e3850e | 2006-01-06 23:04:54 -0800 | [diff] [blame] | 8 | #include <net/xfrm.h> |
| 9 | #include <net/ip.h> |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 10 | |
| 11 | /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */ |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 12 | int ip_route_me_harder(struct sk_buff *skb, unsigned addr_type) |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 13 | { |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 14 | const struct iphdr *iph = ip_hdr(skb); |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 15 | struct rtable *rt; |
| 16 | struct flowi fl = {}; |
| 17 | struct dst_entry *odst; |
| 18 | unsigned int hh_len; |
Patrick McHardy | c68b8b6 | 2007-01-04 12:15:34 -0800 | [diff] [blame] | 19 | unsigned int type; |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 20 | |
Patrick McHardy | c68b8b6 | 2007-01-04 12:15:34 -0800 | [diff] [blame] | 21 | type = inet_addr_type(iph->saddr); |
Simon Horman | b4c4ed1 | 2006-10-02 16:11:13 -0700 | [diff] [blame] | 22 | if (addr_type == RTN_UNSPEC) |
Patrick McHardy | c68b8b6 | 2007-01-04 12:15:34 -0800 | [diff] [blame] | 23 | addr_type = type; |
Simon Horman | b4c4ed1 | 2006-10-02 16:11:13 -0700 | [diff] [blame] | 24 | |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 25 | /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause |
Patrick McHardy | 6e23ae2 | 2007-11-19 18:53:30 -0800 | [diff] [blame^] | 26 | * packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook. |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 27 | */ |
Simon Horman | b4c4ed1 | 2006-10-02 16:11:13 -0700 | [diff] [blame] | 28 | if (addr_type == RTN_LOCAL) { |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 29 | fl.nl_u.ip4_u.daddr = iph->daddr; |
Patrick McHardy | c68b8b6 | 2007-01-04 12:15:34 -0800 | [diff] [blame] | 30 | if (type == RTN_LOCAL) |
| 31 | fl.nl_u.ip4_u.saddr = iph->saddr; |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 32 | fl.nl_u.ip4_u.tos = RT_TOS(iph->tos); |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 33 | fl.oif = skb->sk ? skb->sk->sk_bound_dev_if : 0; |
| 34 | fl.mark = skb->mark; |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 35 | if (ip_route_output_key(&rt, &fl) != 0) |
| 36 | return -1; |
| 37 | |
| 38 | /* Drop old route. */ |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 39 | dst_release(skb->dst); |
| 40 | skb->dst = &rt->u.dst; |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 41 | } else { |
| 42 | /* non-local src, find valid iif to satisfy |
| 43 | * rp-filter when calling ip_route_input. */ |
| 44 | fl.nl_u.ip4_u.daddr = iph->saddr; |
| 45 | if (ip_route_output_key(&rt, &fl) != 0) |
| 46 | return -1; |
| 47 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 48 | odst = skb->dst; |
| 49 | if (ip_route_input(skb, iph->daddr, iph->saddr, |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 50 | RT_TOS(iph->tos), rt->u.dst.dev) != 0) { |
| 51 | dst_release(&rt->u.dst); |
| 52 | return -1; |
| 53 | } |
| 54 | dst_release(&rt->u.dst); |
| 55 | dst_release(odst); |
| 56 | } |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 57 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 58 | if (skb->dst->error) |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 59 | return -1; |
| 60 | |
Patrick McHardy | 3e3850e | 2006-01-06 23:04:54 -0800 | [diff] [blame] | 61 | #ifdef CONFIG_XFRM |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 62 | if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) && |
| 63 | xfrm_decode_session(skb, &fl, AF_INET) == 0) |
| 64 | if (xfrm_lookup(&skb->dst, &fl, skb->sk, 0)) |
Patrick McHardy | 3e3850e | 2006-01-06 23:04:54 -0800 | [diff] [blame] | 65 | return -1; |
| 66 | #endif |
| 67 | |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 68 | /* Change in oif may mean change in hh_len. */ |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 69 | hh_len = skb->dst->dev->hard_header_len; |
| 70 | if (skb_headroom(skb) < hh_len && |
| 71 | pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC)) |
Herbert Xu | 2ca7b0a | 2007-10-14 00:39:55 -0700 | [diff] [blame] | 72 | return -1; |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 73 | |
| 74 | return 0; |
| 75 | } |
| 76 | EXPORT_SYMBOL(ip_route_me_harder); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 77 | |
Patrick McHardy | ee68cea | 2006-02-15 01:34:23 -0800 | [diff] [blame] | 78 | #ifdef CONFIG_XFRM |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 79 | int ip_xfrm_me_harder(struct sk_buff *skb) |
Patrick McHardy | ee68cea | 2006-02-15 01:34:23 -0800 | [diff] [blame] | 80 | { |
| 81 | struct flowi fl; |
| 82 | unsigned int hh_len; |
| 83 | struct dst_entry *dst; |
| 84 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 85 | if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) |
Patrick McHardy | ee68cea | 2006-02-15 01:34:23 -0800 | [diff] [blame] | 86 | return 0; |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 87 | if (xfrm_decode_session(skb, &fl, AF_INET) < 0) |
Patrick McHardy | ee68cea | 2006-02-15 01:34:23 -0800 | [diff] [blame] | 88 | return -1; |
| 89 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 90 | dst = skb->dst; |
Patrick McHardy | ee68cea | 2006-02-15 01:34:23 -0800 | [diff] [blame] | 91 | if (dst->xfrm) |
| 92 | dst = ((struct xfrm_dst *)dst)->route; |
| 93 | dst_hold(dst); |
| 94 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 95 | if (xfrm_lookup(&dst, &fl, skb->sk, 0) < 0) |
Patrick McHardy | ee68cea | 2006-02-15 01:34:23 -0800 | [diff] [blame] | 96 | return -1; |
| 97 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 98 | dst_release(skb->dst); |
| 99 | skb->dst = dst; |
Patrick McHardy | ee68cea | 2006-02-15 01:34:23 -0800 | [diff] [blame] | 100 | |
| 101 | /* Change in oif may mean change in hh_len. */ |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 102 | hh_len = skb->dst->dev->hard_header_len; |
| 103 | if (skb_headroom(skb) < hh_len && |
| 104 | pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC)) |
Herbert Xu | 2ca7b0a | 2007-10-14 00:39:55 -0700 | [diff] [blame] | 105 | return -1; |
Patrick McHardy | ee68cea | 2006-02-15 01:34:23 -0800 | [diff] [blame] | 106 | return 0; |
| 107 | } |
| 108 | EXPORT_SYMBOL(ip_xfrm_me_harder); |
| 109 | #endif |
| 110 | |
Patrick McHardy | eb9c7eb | 2006-01-06 23:06:30 -0800 | [diff] [blame] | 111 | void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); |
| 112 | EXPORT_SYMBOL(ip_nat_decode_session); |
| 113 | |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 114 | /* |
| 115 | * Extra routing may needed on local out, as the QUEUE target never |
| 116 | * returns control to the table. |
| 117 | */ |
| 118 | |
| 119 | struct ip_rt_info { |
Al Viro | 59b8bfd | 2006-09-28 14:21:07 -0700 | [diff] [blame] | 120 | __be32 daddr; |
| 121 | __be32 saddr; |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 122 | u_int8_t tos; |
| 123 | }; |
| 124 | |
Patrick McHardy | bce8032 | 2006-04-06 14:18:09 -0700 | [diff] [blame] | 125 | static void nf_ip_saveroute(const struct sk_buff *skb, struct nf_info *info) |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 126 | { |
| 127 | struct ip_rt_info *rt_info = nf_info_reroute(info); |
| 128 | |
Patrick McHardy | 6e23ae2 | 2007-11-19 18:53:30 -0800 | [diff] [blame^] | 129 | if (info->hook == NF_INET_LOCAL_OUT) { |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 130 | const struct iphdr *iph = ip_hdr(skb); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 131 | |
| 132 | rt_info->tos = iph->tos; |
| 133 | rt_info->daddr = iph->daddr; |
| 134 | rt_info->saddr = iph->saddr; |
| 135 | } |
| 136 | } |
| 137 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 138 | static int nf_ip_reroute(struct sk_buff *skb, const struct nf_info *info) |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 139 | { |
| 140 | const struct ip_rt_info *rt_info = nf_info_reroute(info); |
| 141 | |
Patrick McHardy | 6e23ae2 | 2007-11-19 18:53:30 -0800 | [diff] [blame^] | 142 | if (info->hook == NF_INET_LOCAL_OUT) { |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 143 | const struct iphdr *iph = ip_hdr(skb); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 144 | |
| 145 | if (!(iph->tos == rt_info->tos |
| 146 | && iph->daddr == rt_info->daddr |
| 147 | && iph->saddr == rt_info->saddr)) |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 148 | return ip_route_me_harder(skb, RTN_UNSPEC); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 149 | } |
| 150 | return 0; |
| 151 | } |
| 152 | |
Al Viro | b51655b | 2006-11-14 21:40:42 -0800 | [diff] [blame] | 153 | __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook, |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 154 | unsigned int dataoff, u_int8_t protocol) |
| 155 | { |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 156 | const struct iphdr *iph = ip_hdr(skb); |
Al Viro | b51655b | 2006-11-14 21:40:42 -0800 | [diff] [blame] | 157 | __sum16 csum = 0; |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 158 | |
| 159 | switch (skb->ip_summed) { |
Patrick McHardy | 84fa793 | 2006-08-29 16:44:56 -0700 | [diff] [blame] | 160 | case CHECKSUM_COMPLETE: |
Patrick McHardy | 6e23ae2 | 2007-11-19 18:53:30 -0800 | [diff] [blame^] | 161 | if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN) |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 162 | break; |
Al Viro | d3bc23e | 2006-11-14 21:24:49 -0800 | [diff] [blame] | 163 | if ((protocol == 0 && !csum_fold(skb->csum)) || |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 164 | !csum_tcpudp_magic(iph->saddr, iph->daddr, |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 165 | skb->len - dataoff, protocol, |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 166 | skb->csum)) { |
| 167 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
| 168 | break; |
| 169 | } |
| 170 | /* fall through */ |
| 171 | case CHECKSUM_NONE: |
| 172 | if (protocol == 0) |
| 173 | skb->csum = 0; |
| 174 | else |
| 175 | skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, |
| 176 | skb->len - dataoff, |
| 177 | protocol, 0); |
| 178 | csum = __skb_checksum_complete(skb); |
| 179 | } |
| 180 | return csum; |
| 181 | } |
| 182 | |
| 183 | EXPORT_SYMBOL(nf_ip_checksum); |
| 184 | |
Patrick McHardy | bce8032 | 2006-04-06 14:18:09 -0700 | [diff] [blame] | 185 | static struct nf_afinfo nf_ip_afinfo = { |
| 186 | .family = AF_INET, |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 187 | .checksum = nf_ip_checksum, |
Patrick McHardy | bce8032 | 2006-04-06 14:18:09 -0700 | [diff] [blame] | 188 | .saveroute = nf_ip_saveroute, |
| 189 | .reroute = nf_ip_reroute, |
| 190 | .route_key_size = sizeof(struct ip_rt_info), |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 191 | }; |
| 192 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 193 | static int ipv4_netfilter_init(void) |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 194 | { |
Patrick McHardy | bce8032 | 2006-04-06 14:18:09 -0700 | [diff] [blame] | 195 | return nf_register_afinfo(&nf_ip_afinfo); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 196 | } |
| 197 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 198 | static void ipv4_netfilter_fini(void) |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 199 | { |
Patrick McHardy | bce8032 | 2006-04-06 14:18:09 -0700 | [diff] [blame] | 200 | nf_unregister_afinfo(&nf_ip_afinfo); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 201 | } |
| 202 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 203 | module_init(ipv4_netfilter_init); |
| 204 | module_exit(ipv4_netfilter_fini); |