Patrick McHardy | f229f6c | 2013-04-06 15:24:29 +0200 | [diff] [blame] | 1 | /* |
| 2 | * IPv4 specific functions of netfilter core |
| 3 | * |
| 4 | * Rusty Russell (C) 2000 -- This code is GPL. |
| 5 | * Patrick McHardy (C) 2006-2012 |
| 6 | */ |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 7 | #include <linux/kernel.h> |
| 8 | #include <linux/netfilter.h> |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 9 | #include <linux/netfilter_ipv4.h> |
Patrick McHardy | 3e3850e | 2006-01-06 23:04:54 -0800 | [diff] [blame] | 10 | #include <linux/ip.h> |
Herbert Xu | 2ca7b0a | 2007-10-14 00:39:55 -0700 | [diff] [blame] | 11 | #include <linux/skbuff.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 12 | #include <linux/gfp.h> |
Paul Gortmaker | bc3b2d7 | 2011-07-15 11:47:34 -0400 | [diff] [blame] | 13 | #include <linux/export.h> |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 14 | #include <net/route.h> |
Patrick McHardy | 3e3850e | 2006-01-06 23:04:54 -0800 | [diff] [blame] | 15 | #include <net/xfrm.h> |
| 16 | #include <net/ip.h> |
Patrick McHardy | c01cd42 | 2007-12-05 01:24:48 -0800 | [diff] [blame] | 17 | #include <net/netfilter/nf_queue.h> |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 18 | |
| 19 | /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */ |
Eric W. Biederman | e45f506 | 2015-09-25 15:07:30 -0500 | [diff] [blame] | 20 | int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned int addr_type) |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 21 | { |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 22 | const struct iphdr *iph = ip_hdr(skb); |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 23 | struct rtable *rt; |
David S. Miller | 9d6ec93 | 2011-03-12 01:12:47 -0500 | [diff] [blame] | 24 | struct flowi4 fl4 = {}; |
Julian Anastasov | ed6e4ef | 2011-06-18 07:53:59 +0000 | [diff] [blame] | 25 | __be32 saddr = iph->saddr; |
Florian Westphal | 4211442 | 2017-02-17 08:39:28 +0100 | [diff] [blame] | 26 | const struct sock *sk = skb_to_full_sk(skb); |
| 27 | __u8 flags = sk ? inet_sk_flowi_flags(sk) : 0; |
David Ahern | 6d8b49c | 2016-11-09 10:24:40 -0800 | [diff] [blame] | 28 | struct net_device *dev = skb_dst(skb)->dev; |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 29 | unsigned int hh_len; |
| 30 | |
Julian Anastasov | 797fd39 | 2011-08-07 09:11:00 +0000 | [diff] [blame] | 31 | if (addr_type == RTN_UNSPEC) |
David Ahern | 6d8b49c | 2016-11-09 10:24:40 -0800 | [diff] [blame] | 32 | addr_type = inet_addr_type_dev_table(net, dev, saddr); |
Julian Anastasov | 797fd39 | 2011-08-07 09:11:00 +0000 | [diff] [blame] | 33 | if (addr_type == RTN_LOCAL || addr_type == RTN_UNICAST) |
| 34 | flags |= FLOWI_FLAG_ANYSRC; |
| 35 | else |
| 36 | saddr = 0; |
Simon Horman | b4c4ed1 | 2006-10-02 16:11:13 -0700 | [diff] [blame] | 37 | |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 38 | /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause |
Patrick McHardy | 6e23ae2 | 2007-11-19 18:53:30 -0800 | [diff] [blame] | 39 | * 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] | 40 | */ |
Julian Anastasov | ed6e4ef | 2011-06-18 07:53:59 +0000 | [diff] [blame] | 41 | fl4.daddr = iph->daddr; |
| 42 | fl4.saddr = saddr; |
| 43 | fl4.flowi4_tos = RT_TOS(iph->tos); |
Florian Westphal | 4211442 | 2017-02-17 08:39:28 +0100 | [diff] [blame] | 44 | fl4.flowi4_oif = sk ? sk->sk_bound_dev_if : 0; |
David Ahern | 6d8b49c | 2016-11-09 10:24:40 -0800 | [diff] [blame] | 45 | if (!fl4.flowi4_oif) |
| 46 | fl4.flowi4_oif = l3mdev_master_ifindex(dev); |
Julian Anastasov | ed6e4ef | 2011-06-18 07:53:59 +0000 | [diff] [blame] | 47 | fl4.flowi4_mark = skb->mark; |
Julian Anastasov | 797fd39 | 2011-08-07 09:11:00 +0000 | [diff] [blame] | 48 | fl4.flowi4_flags = flags; |
Julian Anastasov | ed6e4ef | 2011-06-18 07:53:59 +0000 | [diff] [blame] | 49 | rt = ip_route_output_key(net, &fl4); |
| 50 | if (IS_ERR(rt)) |
Patrick McHardy | c9e1673 | 2013-04-05 06:41:10 +0000 | [diff] [blame] | 51 | return PTR_ERR(rt); |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 52 | |
Julian Anastasov | ed6e4ef | 2011-06-18 07:53:59 +0000 | [diff] [blame] | 53 | /* Drop old route. */ |
| 54 | skb_dst_drop(skb); |
| 55 | skb_dst_set(skb, &rt->dst); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 56 | |
Eric Dumazet | adf3090 | 2009-06-02 05:19:30 +0000 | [diff] [blame] | 57 | if (skb_dst(skb)->error) |
Patrick McHardy | c9e1673 | 2013-04-05 06:41:10 +0000 | [diff] [blame] | 58 | return skb_dst(skb)->error; |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 59 | |
Patrick McHardy | 3e3850e | 2006-01-06 23:04:54 -0800 | [diff] [blame] | 60 | #ifdef CONFIG_XFRM |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 61 | if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) && |
David S. Miller | 9d6ec93 | 2011-03-12 01:12:47 -0500 | [diff] [blame] | 62 | xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) { |
Eric Dumazet | adf3090 | 2009-06-02 05:19:30 +0000 | [diff] [blame] | 63 | struct dst_entry *dst = skb_dst(skb); |
| 64 | skb_dst_set(skb, NULL); |
Florian Westphal | 4211442 | 2017-02-17 08:39:28 +0100 | [diff] [blame] | 65 | dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), sk, 0); |
David S. Miller | 452edd5 | 2011-03-02 13:27:41 -0800 | [diff] [blame] | 66 | if (IS_ERR(dst)) |
stephen hemminger | 3d0a062 | 2014-01-15 08:12:50 -0800 | [diff] [blame] | 67 | return PTR_ERR(dst); |
Eric Dumazet | adf3090 | 2009-06-02 05:19:30 +0000 | [diff] [blame] | 68 | skb_dst_set(skb, dst); |
| 69 | } |
Patrick McHardy | 3e3850e | 2006-01-06 23:04:54 -0800 | [diff] [blame] | 70 | #endif |
| 71 | |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 72 | /* Change in oif may mean change in hh_len. */ |
Eric Dumazet | adf3090 | 2009-06-02 05:19:30 +0000 | [diff] [blame] | 73 | hh_len = skb_dst(skb)->dev->hard_header_len; |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 74 | if (skb_headroom(skb) < hh_len && |
Paul Guo | 5e2afba | 2011-11-14 19:00:54 +0800 | [diff] [blame] | 75 | pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)), |
| 76 | 0, GFP_ATOMIC)) |
Patrick McHardy | c9e1673 | 2013-04-05 06:41:10 +0000 | [diff] [blame] | 77 | return -ENOMEM; |
Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame] | 78 | |
| 79 | return 0; |
| 80 | } |
| 81 | EXPORT_SYMBOL(ip_route_me_harder); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 82 | |
| 83 | /* |
| 84 | * Extra routing may needed on local out, as the QUEUE target never |
| 85 | * returns control to the table. |
| 86 | */ |
| 87 | |
| 88 | struct ip_rt_info { |
Al Viro | 59b8bfd | 2006-09-28 14:21:07 -0700 | [diff] [blame] | 89 | __be32 daddr; |
| 90 | __be32 saddr; |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 91 | u_int8_t tos; |
Eric Leblond | 5f145e4 | 2008-11-25 12:15:16 +0100 | [diff] [blame] | 92 | u_int32_t mark; |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 93 | }; |
| 94 | |
Patrick McHardy | 02f014d | 2007-12-05 01:26:33 -0800 | [diff] [blame] | 95 | static void nf_ip_saveroute(const struct sk_buff *skb, |
| 96 | struct nf_queue_entry *entry) |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 97 | { |
Patrick McHardy | 02f014d | 2007-12-05 01:26:33 -0800 | [diff] [blame] | 98 | struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 99 | |
David S. Miller | 1d1de89 | 2015-04-03 16:31:01 -0400 | [diff] [blame] | 100 | if (entry->state.hook == NF_INET_LOCAL_OUT) { |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 101 | const struct iphdr *iph = ip_hdr(skb); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 102 | |
| 103 | rt_info->tos = iph->tos; |
| 104 | rt_info->daddr = iph->daddr; |
| 105 | rt_info->saddr = iph->saddr; |
Eric Leblond | 5f145e4 | 2008-11-25 12:15:16 +0100 | [diff] [blame] | 106 | rt_info->mark = skb->mark; |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 107 | } |
| 108 | } |
| 109 | |
Eric W. Biederman | d815d90 | 2015-09-25 15:07:28 -0500 | [diff] [blame] | 110 | static int nf_ip_reroute(struct net *net, struct sk_buff *skb, |
Patrick McHardy | 02f014d | 2007-12-05 01:26:33 -0800 | [diff] [blame] | 111 | const struct nf_queue_entry *entry) |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 112 | { |
Patrick McHardy | 02f014d | 2007-12-05 01:26:33 -0800 | [diff] [blame] | 113 | const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 114 | |
David S. Miller | 1d1de89 | 2015-04-03 16:31:01 -0400 | [diff] [blame] | 115 | if (entry->state.hook == NF_INET_LOCAL_OUT) { |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 116 | const struct iphdr *iph = ip_hdr(skb); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 117 | |
Joe Perches | f64f9e7 | 2009-11-29 16:55:45 -0800 | [diff] [blame] | 118 | if (!(iph->tos == rt_info->tos && |
| 119 | skb->mark == rt_info->mark && |
| 120 | iph->daddr == rt_info->daddr && |
| 121 | iph->saddr == rt_info->saddr)) |
Eric W. Biederman | e45f506 | 2015-09-25 15:07:30 -0500 | [diff] [blame] | 122 | return ip_route_me_harder(net, skb, RTN_UNSPEC); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 123 | } |
| 124 | return 0; |
| 125 | } |
| 126 | |
Al Viro | b51655b | 2006-11-14 21:40:42 -0800 | [diff] [blame] | 127 | __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook, |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 128 | unsigned int dataoff, u_int8_t protocol) |
| 129 | { |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 130 | const struct iphdr *iph = ip_hdr(skb); |
Al Viro | b51655b | 2006-11-14 21:40:42 -0800 | [diff] [blame] | 131 | __sum16 csum = 0; |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 132 | |
| 133 | switch (skb->ip_summed) { |
Patrick McHardy | 84fa793 | 2006-08-29 16:44:56 -0700 | [diff] [blame] | 134 | case CHECKSUM_COMPLETE: |
Patrick McHardy | 6e23ae2 | 2007-11-19 18:53:30 -0800 | [diff] [blame] | 135 | if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN) |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 136 | break; |
Al Viro | d3bc23e | 2006-11-14 21:24:49 -0800 | [diff] [blame] | 137 | if ((protocol == 0 && !csum_fold(skb->csum)) || |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 138 | !csum_tcpudp_magic(iph->saddr, iph->daddr, |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 139 | skb->len - dataoff, protocol, |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 140 | skb->csum)) { |
| 141 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
| 142 | break; |
| 143 | } |
| 144 | /* fall through */ |
| 145 | case CHECKSUM_NONE: |
| 146 | if (protocol == 0) |
| 147 | skb->csum = 0; |
| 148 | else |
| 149 | skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, |
| 150 | skb->len - dataoff, |
| 151 | protocol, 0); |
| 152 | csum = __skb_checksum_complete(skb); |
| 153 | } |
| 154 | return csum; |
| 155 | } |
Patrick McHardy | 422c346 | 2006-04-06 14:18:43 -0700 | [diff] [blame] | 156 | EXPORT_SYMBOL(nf_ip_checksum); |
| 157 | |
Patrick McHardy | d63a650 | 2008-03-20 15:15:53 +0100 | [diff] [blame] | 158 | static __sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook, |
| 159 | unsigned int dataoff, unsigned int len, |
| 160 | u_int8_t protocol) |
| 161 | { |
| 162 | const struct iphdr *iph = ip_hdr(skb); |
| 163 | __sum16 csum = 0; |
| 164 | |
| 165 | switch (skb->ip_summed) { |
| 166 | case CHECKSUM_COMPLETE: |
| 167 | if (len == skb->len - dataoff) |
| 168 | return nf_ip_checksum(skb, hook, dataoff, protocol); |
| 169 | /* fall through */ |
| 170 | case CHECKSUM_NONE: |
| 171 | skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, protocol, |
| 172 | skb->len - dataoff, 0); |
| 173 | skb->ip_summed = CHECKSUM_NONE; |
Shan Wei | c86ee67 | 2010-06-14 16:20:02 +0200 | [diff] [blame] | 174 | return __skb_checksum_complete_head(skb, dataoff + len); |
Patrick McHardy | d63a650 | 2008-03-20 15:15:53 +0100 | [diff] [blame] | 175 | } |
| 176 | return csum; |
| 177 | } |
| 178 | |
Florian Westphal | 31ad3dd | 2011-04-04 16:56:29 +0200 | [diff] [blame] | 179 | static int nf_ip_route(struct net *net, struct dst_entry **dst, |
Florian Westphal | 0fae2e7 | 2011-04-04 17:00:54 +0200 | [diff] [blame] | 180 | struct flowi *fl, bool strict __always_unused) |
Patrick McHardy | 1841a4c | 2007-12-05 01:22:05 -0800 | [diff] [blame] | 181 | { |
Florian Westphal | 31ad3dd | 2011-04-04 16:56:29 +0200 | [diff] [blame] | 182 | struct rtable *rt = ip_route_output_key(net, &fl->u.ip4); |
David S. Miller | b23dd4f | 2011-03-02 14:31:35 -0800 | [diff] [blame] | 183 | if (IS_ERR(rt)) |
| 184 | return PTR_ERR(rt); |
| 185 | *dst = &rt->dst; |
| 186 | return 0; |
Patrick McHardy | 1841a4c | 2007-12-05 01:22:05 -0800 | [diff] [blame] | 187 | } |
| 188 | |
Patrick McHardy | 1e796fd | 2007-12-17 22:42:27 -0800 | [diff] [blame] | 189 | static const struct nf_afinfo nf_ip_afinfo = { |
Patrick McHardy | d63a650 | 2008-03-20 15:15:53 +0100 | [diff] [blame] | 190 | .family = AF_INET, |
| 191 | .checksum = nf_ip_checksum, |
| 192 | .checksum_partial = nf_ip_checksum_partial, |
| 193 | .route = nf_ip_route, |
| 194 | .saveroute = nf_ip_saveroute, |
| 195 | .reroute = nf_ip_reroute, |
| 196 | .route_key_size = sizeof(struct ip_rt_info), |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 197 | }; |
| 198 | |
Jan Beulich | ce9f3f3 | 2012-06-18 00:18:31 +0000 | [diff] [blame] | 199 | static int __init ipv4_netfilter_init(void) |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 200 | { |
Patrick McHardy | bce8032 | 2006-04-06 14:18:09 -0700 | [diff] [blame] | 201 | return nf_register_afinfo(&nf_ip_afinfo); |
Harald Welte | 2cc7d57 | 2005-08-09 19:42:34 -0700 | [diff] [blame] | 202 | } |
Paul Gortmaker | 5533106 | 2015-05-01 20:08:20 -0400 | [diff] [blame] | 203 | subsys_initcall(ipv4_netfilter_init); |