xref: /linux/net/ipv6/xfrm6_input.c (revision 95db3b255fde4e830e5f8cc011eb404023f669d4)
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_SPI_SKB_CB(skb)->family = AF_INET6;
27 	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
28 	return xfrm_input(skb, nexthdr, spi, 0);
29 }
30 EXPORT_SYMBOL(xfrm6_rcv_spi);
31 
32 int xfrm6_transport_finish(struct sk_buff *skb, int async)
33 {
34 	skb_network_header(skb)[IP6CB(skb)->nhoff] =
35 		XFRM_MODE_SKB_CB(skb)->protocol;
36 
37 #ifndef CONFIG_NETFILTER
38 	if (!async)
39 		return 1;
40 #endif
41 
42 	ipv6_hdr(skb)->payload_len = htons(skb->len);
43 	__skb_push(skb, skb->data - skb_network_header(skb));
44 
45 	NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
46 		dev_net(skb->dev), NULL, skb, skb->dev, NULL,
47 		ip6_rcv_finish);
48 	return -1;
49 }
50 
51 int xfrm6_rcv(struct sk_buff *skb)
52 {
53 	return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
54 			     0);
55 }
56 EXPORT_SYMBOL(xfrm6_rcv);
57 
58 int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
59 		     xfrm_address_t *saddr, u8 proto)
60 {
61 	struct net *net = dev_net(skb->dev);
62 	struct xfrm_state *x = NULL;
63 	int i = 0;
64 
65 	/* Allocate new secpath or COW existing one. */
66 	if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
67 		struct sec_path *sp;
68 
69 		sp = secpath_dup(skb->sp);
70 		if (!sp) {
71 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
72 			goto drop;
73 		}
74 		if (skb->sp)
75 			secpath_put(skb->sp);
76 		skb->sp = sp;
77 	}
78 
79 	if (1 + skb->sp->len == XFRM_MAX_DEPTH) {
80 		XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
81 		goto drop;
82 	}
83 
84 	for (i = 0; i < 3; i++) {
85 		xfrm_address_t *dst, *src;
86 
87 		switch (i) {
88 		case 0:
89 			dst = daddr;
90 			src = saddr;
91 			break;
92 		case 1:
93 			/* lookup state with wild-card source address */
94 			dst = daddr;
95 			src = (xfrm_address_t *)&in6addr_any;
96 			break;
97 		default:
98 			/* lookup state with wild-card addresses */
99 			dst = (xfrm_address_t *)&in6addr_any;
100 			src = (xfrm_address_t *)&in6addr_any;
101 			break;
102 		}
103 
104 		x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6);
105 		if (!x)
106 			continue;
107 
108 		spin_lock(&x->lock);
109 
110 		if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) &&
111 		    likely(x->km.state == XFRM_STATE_VALID) &&
112 		    !xfrm_state_check_expire(x)) {
113 			spin_unlock(&x->lock);
114 			if (x->type->input(x, skb) > 0) {
115 				/* found a valid state */
116 				break;
117 			}
118 		} else
119 			spin_unlock(&x->lock);
120 
121 		xfrm_state_put(x);
122 		x = NULL;
123 	}
124 
125 	if (!x) {
126 		XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
127 		xfrm_audit_state_notfound_simple(skb, AF_INET6);
128 		goto drop;
129 	}
130 
131 	skb->sp->xvec[skb->sp->len++] = x;
132 
133 	spin_lock(&x->lock);
134 
135 	x->curlft.bytes += skb->len;
136 	x->curlft.packets++;
137 
138 	spin_unlock(&x->lock);
139 
140 	return 1;
141 
142 drop:
143 	return -1;
144 }
145 EXPORT_SYMBOL(xfrm6_input_addr);
146