xref: /linux/net/ipv6/xfrm6_input.c (revision 161db5d165123a72792e2687ecfd8de146dbae1a)
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 {
26 	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
27 	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
28 	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
29 	return xfrm_input(skb, nexthdr, spi, 0);
30 }
31 EXPORT_SYMBOL(xfrm6_rcv_spi);
32 
33 int xfrm6_transport_finish(struct sk_buff *skb, int async)
34 {
35 	skb_network_header(skb)[IP6CB(skb)->nhoff] =
36 		XFRM_MODE_SKB_CB(skb)->protocol;
37 
38 #ifndef CONFIG_NETFILTER
39 	if (!async)
40 		return 1;
41 #endif
42 
43 	ipv6_hdr(skb)->payload_len = htons(skb->len);
44 	__skb_push(skb, skb->data - skb_network_header(skb));
45 
46 	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
47 		dev_net(skb->dev), NULL, skb, skb->dev, NULL,
48 		ip6_rcv_finish);
49 	return -1;
50 }
51 
52 int xfrm6_rcv(struct sk_buff *skb)
53 {
54 	return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
55 			     0);
56 }
57 EXPORT_SYMBOL(xfrm6_rcv);
58 
59 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
60 		     xfrm_address_t *saddr, u8 proto)
61 {
62 	struct net *net = dev_net(skb->dev);
63 	struct xfrm_state *x = NULL;
64 	int i = 0;
65 
66 	/* Allocate new secpath or COW existing one. */
67 	if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
68 		struct sec_path *sp;
69 
70 		sp = secpath_dup(skb->sp);
71 		if (!sp) {
72 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
73 			goto drop;
74 		}
75 		if (skb->sp)
76 			secpath_put(skb->sp);
77 		skb->sp = sp;
78 	}
79 
80 	if (1 + skb->sp->len == XFRM_MAX_DEPTH) {
81 		XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
82 		goto drop;
83 	}
84 
85 	for (i = 0; i < 3; i++) {
86 		xfrm_address_t *dst, *src;
87 
88 		switch (i) {
89 		case 0:
90 			dst = daddr;
91 			src = saddr;
92 			break;
93 		case 1:
94 			/* lookup state with wild-card source address */
95 			dst = daddr;
96 			src = (xfrm_address_t *)&in6addr_any;
97 			break;
98 		default:
99 			/* lookup state with wild-card addresses */
100 			dst = (xfrm_address_t *)&in6addr_any;
101 			src = (xfrm_address_t *)&in6addr_any;
102 			break;
103 		}
104 
105 		x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6);
106 		if (!x)
107 			continue;
108 
109 		spin_lock(&x->lock);
110 
111 		if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) &&
112 		    likely(x->km.state == XFRM_STATE_VALID) &&
113 		    !xfrm_state_check_expire(x)) {
114 			spin_unlock(&x->lock);
115 			if (x->type->input(x, skb) > 0) {
116 				/* found a valid state */
117 				break;
118 			}
119 		} else
120 			spin_unlock(&x->lock);
121 
122 		xfrm_state_put(x);
123 		x = NULL;
124 	}
125 
126 	if (!x) {
127 		XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
128 		xfrm_audit_state_notfound_simple(skb, AF_INET6);
129 		goto drop;
130 	}
131 
132 	skb->sp->xvec[skb->sp->len++] = x;
133 
134 	spin_lock(&x->lock);
135 
136 	x->curlft.bytes += skb->len;
137 	x->curlft.packets++;
138 
139 	spin_unlock(&x->lock);
140 
141 	return 1;
142 
143 drop:
144 	return -1;
145 }
146 EXPORT_SYMBOL(xfrm6_input_addr);
147