mm, fs, dax: handle layout changes to pinned dax mappings
[linux-block.git] / net / ipv4 / netfilter.c
CommitLineData
f229f6ce
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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>
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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 20int 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;
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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
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68 skb_dst_set(skb, dst);
69 }
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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
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78
79 return 0;
80}
81EXPORT_SYMBOL(ip_route_me_harder);
2cc7d573 82
ce388f45 83int nf_ip_reroute(struct sk_buff *skb, const struct nf_queue_entry *entry)
2cc7d573 84{
02f014d8 85 const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
2cc7d573 86
1d1de89b 87 if (entry->state.hook == NF_INET_LOCAL_OUT) {
3db05fea 88 const struct iphdr *iph = ip_hdr(skb);
2cc7d573 89
f64f9e71
JP
90 if (!(iph->tos == rt_info->tos &&
91 skb->mark == rt_info->mark &&
92 iph->daddr == rt_info->daddr &&
93 iph->saddr == rt_info->saddr))
ce388f45
PNA
94 return ip_route_me_harder(entry->state.net, skb,
95 RTN_UNSPEC);
2cc7d573
HW
96 }
97 return 0;
98}
ce388f45 99EXPORT_SYMBOL_GPL(nf_ip_reroute);
2cc7d573 100
b51655b9 101__sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
422c346f
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102 unsigned int dataoff, u_int8_t protocol)
103{
eddc9ec5 104 const struct iphdr *iph = ip_hdr(skb);
b51655b9 105 __sum16 csum = 0;
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106
107 switch (skb->ip_summed) {
84fa7933 108 case CHECKSUM_COMPLETE:
6e23ae2a 109 if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN)
422c346f 110 break;
d3bc23e7 111 if ((protocol == 0 && !csum_fold(skb->csum)) ||
422c346f 112 !csum_tcpudp_magic(iph->saddr, iph->daddr,
e905a9ed 113 skb->len - dataoff, protocol,
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114 skb->csum)) {
115 skb->ip_summed = CHECKSUM_UNNECESSARY;
116 break;
117 }
118 /* fall through */
119 case CHECKSUM_NONE:
120 if (protocol == 0)
121 skb->csum = 0;
122 else
123 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
124 skb->len - dataoff,
125 protocol, 0);
126 csum = __skb_checksum_complete(skb);
127 }
128 return csum;
129}
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130EXPORT_SYMBOL(nf_ip_checksum);
131
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132__sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook,
133 unsigned int dataoff, unsigned int len,
134 u_int8_t protocol)
d63a6507
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135{
136 const struct iphdr *iph = ip_hdr(skb);
137 __sum16 csum = 0;
138
139 switch (skb->ip_summed) {
140 case CHECKSUM_COMPLETE:
141 if (len == skb->len - dataoff)
142 return nf_ip_checksum(skb, hook, dataoff, protocol);
143 /* fall through */
144 case CHECKSUM_NONE:
145 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, protocol,
146 skb->len - dataoff, 0);
147 skb->ip_summed = CHECKSUM_NONE;
c86ee67c 148 return __skb_checksum_complete_head(skb, dataoff + len);
d63a6507
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149 }
150 return csum;
151}
f7dcbe2f 152EXPORT_SYMBOL_GPL(nf_ip_checksum_partial);
d63a6507 153
3f87c08c
PNA
154int nf_ip_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
155 bool strict __always_unused)
1841a4c7 156{
31ad3dd6 157 struct rtable *rt = ip_route_output_key(net, &fl->u.ip4);
b23dd4fe
DM
158 if (IS_ERR(rt))
159 return PTR_ERR(rt);
160 *dst = &rt->dst;
161 return 0;
1841a4c7 162}
3f87c08c 163EXPORT_SYMBOL_GPL(nf_ip_route);