xref: /linux/net/ipv6/xfrm6_input.c (revision f3a8b6645dc2e60d11f20c1c23afd964ff4e55ae)
1 /*
2  * xfrm6_input.c: based on net/ipv4/xfrm4_input.c
3  *
4  * Authors:
5  *	Mitsuru KANDA @USAGI
6  *	Kazunori MIYAZAWA @USAGI
7  *	Kunihiro Ishiguro <kunihiro@ipinfusion.com>
8  *	YOSHIFUJI Hideaki @USAGI
9  *		IPv6 support
10  */
11 
12 #include <linux/module.h>
13 #include <linux/string.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter_ipv6.h>
16 #include <net/ipv6.h>
17 #include <net/xfrm.h>
18 
19 int xfrm6_extract_input(struct xfrm_state *x, struct sk_buff *skb)
20 {
21 	return xfrm6_extract_header(skb);
22 }
23 
24 int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi,
25 		  struct ip6_tnl *t)
26 {
27 	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = t;
28 	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
29 	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
30 	return xfrm_input(skb, nexthdr, spi, 0);
31 }
32 EXPORT_SYMBOL(xfrm6_rcv_spi);
33 
34 int xfrm6_transport_finish(struct sk_buff *skb, int async)
35 {
36 	skb_network_header(skb)[IP6CB(skb)->nhoff] =
37 		XFRM_MODE_SKB_CB(skb)->protocol;
38 
39 #ifndef CONFIG_NETFILTER
40 	if (!async)
41 		return 1;
42 #endif
43 
44 	ipv6_hdr(skb)->payload_len = htons(skb->len);
45 	__skb_push(skb, skb->data - skb_network_header(skb));
46 
47 	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
48 		dev_net(skb->dev), NULL, skb, skb->dev, NULL,
49 		ip6_rcv_finish);
50 	return -1;
51 }
52 
53 int xfrm6_rcv_tnl(struct sk_buff *skb, struct ip6_tnl *t)
54 {
55 	return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
56 			     0, t);
57 }
58 EXPORT_SYMBOL(xfrm6_rcv_tnl);
59 
60 int xfrm6_rcv(struct sk_buff *skb)
61 {
62 	return xfrm6_rcv_tnl(skb, NULL);
63 }
64 EXPORT_SYMBOL(xfrm6_rcv);
65 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
66 		     xfrm_address_t *saddr, u8 proto)
67 {
68 	struct net *net = dev_net(skb->dev);
69 	struct xfrm_state *x = NULL;
70 	int i = 0;
71 
72 	/* Allocate new secpath or COW existing one. */
73 	if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
74 		struct sec_path *sp;
75 
76 		sp = secpath_dup(skb->sp);
77 		if (!sp) {
78 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
79 			goto drop;
80 		}
81 		if (skb->sp)
82 			secpath_put(skb->sp);
83 		skb->sp = sp;
84 	}
85 
86 	if (1 + skb->sp->len == XFRM_MAX_DEPTH) {
87 		XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
88 		goto drop;
89 	}
90 
91 	for (i = 0; i < 3; i++) {
92 		xfrm_address_t *dst, *src;
93 
94 		switch (i) {
95 		case 0:
96 			dst = daddr;
97 			src = saddr;
98 			break;
99 		case 1:
100 			/* lookup state with wild-card source address */
101 			dst = daddr;
102 			src = (xfrm_address_t *)&in6addr_any;
103 			break;
104 		default:
105 			/* lookup state with wild-card addresses */
106 			dst = (xfrm_address_t *)&in6addr_any;
107 			src = (xfrm_address_t *)&in6addr_any;
108 			break;
109 		}
110 
111 		x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6);
112 		if (!x)
113 			continue;
114 
115 		spin_lock(&x->lock);
116 
117 		if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) &&
118 		    likely(x->km.state == XFRM_STATE_VALID) &&
119 		    !xfrm_state_check_expire(x)) {
120 			spin_unlock(&x->lock);
121 			if (x->type->input(x, skb) > 0) {
122 				/* found a valid state */
123 				break;
124 			}
125 		} else
126 			spin_unlock(&x->lock);
127 
128 		xfrm_state_put(x);
129 		x = NULL;
130 	}
131 
132 	if (!x) {
133 		XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
134 		xfrm_audit_state_notfound_simple(skb, AF_INET6);
135 		goto drop;
136 	}
137 
138 	skb->sp->xvec[skb->sp->len++] = x;
139 
140 	spin_lock(&x->lock);
141 
142 	x->curlft.bytes += skb->len;
143 	x->curlft.packets++;
144 
145 	spin_unlock(&x->lock);
146 
147 	return 1;
148 
149 drop:
150 	return -1;
151 }
152 EXPORT_SYMBOL(xfrm6_input_addr);
153