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Commit | Line | Data |
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f229f6ce PM |
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 | */ | |
020b4c12 HW |
7 | #include <linux/kernel.h> |
8 | #include <linux/netfilter.h> | |
2cc7d573 | 9 | #include <linux/netfilter_ipv4.h> |
3e3850e9 | 10 | #include <linux/ip.h> |
2ca7b0ac | 11 | #include <linux/skbuff.h> |
5a0e3ad6 | 12 | #include <linux/gfp.h> |
bc3b2d7f | 13 | #include <linux/export.h> |
020b4c12 | 14 | #include <net/route.h> |
3e3850e9 PM |
15 | #include <net/xfrm.h> |
16 | #include <net/ip.h> | |
c01cd429 | 17 | #include <net/netfilter/nf_queue.h> |
020b4c12 HW |
18 | |
19 | /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */ | |
e45f5066 | 20 | int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned int addr_type) |
020b4c12 | 21 | { |
3db05fea | 22 | const struct iphdr *iph = ip_hdr(skb); |
020b4c12 | 23 | struct rtable *rt; |
9d6ec938 | 24 | struct flowi4 fl4 = {}; |
ed6e4ef8 | 25 | __be32 saddr = iph->saddr; |
29e09229 FW |
26 | const struct sock *sk = skb_to_full_sk(skb); |
27 | __u8 flags = sk ? inet_sk_flowi_flags(sk) : 0; | |
6d8b49c3 | 28 | struct net_device *dev = skb_dst(skb)->dev; |
020b4c12 HW |
29 | unsigned int hh_len; |
30 | ||
797fd391 | 31 | if (addr_type == RTN_UNSPEC) |
6d8b49c3 | 32 | addr_type = inet_addr_type_dev_table(net, dev, saddr); |
797fd391 JA |
33 | if (addr_type == RTN_LOCAL || addr_type == RTN_UNICAST) |
34 | flags |= FLOWI_FLAG_ANYSRC; | |
35 | else | |
36 | saddr = 0; | |
b4c4ed17 | 37 | |
020b4c12 | 38 | /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause |
6e23ae2a | 39 | * packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook. |
020b4c12 | 40 | */ |
ed6e4ef8 JA |
41 | fl4.daddr = iph->daddr; |
42 | fl4.saddr = saddr; | |
43 | fl4.flowi4_tos = RT_TOS(iph->tos); | |
29e09229 | 44 | fl4.flowi4_oif = sk ? sk->sk_bound_dev_if : 0; |
6d8b49c3 DA |
45 | if (!fl4.flowi4_oif) |
46 | fl4.flowi4_oif = l3mdev_master_ifindex(dev); | |
ed6e4ef8 | 47 | fl4.flowi4_mark = skb->mark; |
797fd391 | 48 | fl4.flowi4_flags = flags; |
ed6e4ef8 JA |
49 | rt = ip_route_output_key(net, &fl4); |
50 | if (IS_ERR(rt)) | |
c9e1673a | 51 | return PTR_ERR(rt); |
020b4c12 | 52 | |
ed6e4ef8 JA |
53 | /* Drop old route. */ |
54 | skb_dst_drop(skb); | |
55 | skb_dst_set(skb, &rt->dst); | |
e905a9ed | 56 | |
adf30907 | 57 | if (skb_dst(skb)->error) |
c9e1673a | 58 | return skb_dst(skb)->error; |
020b4c12 | 59 | |
3e3850e9 | 60 | #ifdef CONFIG_XFRM |
3db05fea | 61 | if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) && |
9d6ec938 | 62 | xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) { |
adf30907 ED |
63 | struct dst_entry *dst = skb_dst(skb); |
64 | skb_dst_set(skb, NULL); | |
29e09229 | 65 | dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), sk, 0); |
452edd59 | 66 | if (IS_ERR(dst)) |
3d0a0620 | 67 | return PTR_ERR(dst); |
adf30907 ED |
68 | skb_dst_set(skb, dst); |
69 | } | |
3e3850e9 PM |
70 | #endif |
71 | ||
020b4c12 | 72 | /* Change in oif may mean change in hh_len. */ |
adf30907 | 73 | hh_len = skb_dst(skb)->dev->hard_header_len; |
3db05fea | 74 | if (skb_headroom(skb) < hh_len && |
5e2afba4 PG |
75 | pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)), |
76 | 0, GFP_ATOMIC)) | |
c9e1673a | 77 | return -ENOMEM; |
020b4c12 HW |
78 | |
79 | return 0; | |
80 | } | |
81 | EXPORT_SYMBOL(ip_route_me_harder); | |
2cc7d573 HW |
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 { | |
59b8bfd8 AV |
89 | __be32 daddr; |
90 | __be32 saddr; | |
2cc7d573 | 91 | u_int8_t tos; |
5f145e44 | 92 | u_int32_t mark; |
2cc7d573 HW |
93 | }; |
94 | ||
02f014d8 PM |
95 | static void nf_ip_saveroute(const struct sk_buff *skb, |
96 | struct nf_queue_entry *entry) | |
2cc7d573 | 97 | { |
02f014d8 | 98 | struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry); |
2cc7d573 | 99 | |
1d1de89b | 100 | if (entry->state.hook == NF_INET_LOCAL_OUT) { |
eddc9ec5 | 101 | const struct iphdr *iph = ip_hdr(skb); |
2cc7d573 HW |
102 | |
103 | rt_info->tos = iph->tos; | |
104 | rt_info->daddr = iph->daddr; | |
105 | rt_info->saddr = iph->saddr; | |
5f145e44 | 106 | rt_info->mark = skb->mark; |
2cc7d573 HW |
107 | } |
108 | } | |
109 | ||
d815d90b | 110 | static int nf_ip_reroute(struct net *net, struct sk_buff *skb, |
02f014d8 | 111 | const struct nf_queue_entry *entry) |
2cc7d573 | 112 | { |
02f014d8 | 113 | const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry); |
2cc7d573 | 114 | |
1d1de89b | 115 | if (entry->state.hook == NF_INET_LOCAL_OUT) { |
3db05fea | 116 | const struct iphdr *iph = ip_hdr(skb); |
2cc7d573 | 117 | |
f64f9e71 JP |
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)) | |
e45f5066 | 122 | return ip_route_me_harder(net, skb, RTN_UNSPEC); |
2cc7d573 HW |
123 | } |
124 | return 0; | |
125 | } | |
126 | ||
b51655b9 | 127 | __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook, |
422c346f PM |
128 | unsigned int dataoff, u_int8_t protocol) |
129 | { | |
eddc9ec5 | 130 | const struct iphdr *iph = ip_hdr(skb); |
b51655b9 | 131 | __sum16 csum = 0; |
422c346f PM |
132 | |
133 | switch (skb->ip_summed) { | |
84fa7933 | 134 | case CHECKSUM_COMPLETE: |
6e23ae2a | 135 | if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN) |
422c346f | 136 | break; |
d3bc23e7 | 137 | if ((protocol == 0 && !csum_fold(skb->csum)) || |
422c346f | 138 | !csum_tcpudp_magic(iph->saddr, iph->daddr, |
e905a9ed | 139 | skb->len - dataoff, protocol, |
422c346f PM |
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 | } | |
422c346f PM |
156 | EXPORT_SYMBOL(nf_ip_checksum); |
157 | ||
d63a6507 PM |
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; | |
c86ee67c | 174 | return __skb_checksum_complete_head(skb, dataoff + len); |
d63a6507 PM |
175 | } |
176 | return csum; | |
177 | } | |
178 | ||
31ad3dd6 | 179 | static int nf_ip_route(struct net *net, struct dst_entry **dst, |
0fae2e77 | 180 | struct flowi *fl, bool strict __always_unused) |
1841a4c7 | 181 | { |
31ad3dd6 | 182 | struct rtable *rt = ip_route_output_key(net, &fl->u.ip4); |
b23dd4fe DM |
183 | if (IS_ERR(rt)) |
184 | return PTR_ERR(rt); | |
185 | *dst = &rt->dst; | |
186 | return 0; | |
1841a4c7 PM |
187 | } |
188 | ||
1e796fda | 189 | static const struct nf_afinfo nf_ip_afinfo = { |
d63a6507 PM |
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), | |
2cc7d573 HW |
197 | }; |
198 | ||
ce9f3f31 | 199 | static int __init ipv4_netfilter_init(void) |
2cc7d573 | 200 | { |
bce8032e | 201 | return nf_register_afinfo(&nf_ip_afinfo); |
2cc7d573 | 202 | } |
55331060 | 203 | subsys_initcall(ipv4_netfilter_init); |