1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173 |
4 | * |
5 | * Copyright (C)2003 USAGI/WIDE Project |
6 | * |
7 | * Author Mitsuru KANDA <mk@linux-ipv6.org> |
8 | */ |
9 | /* |
10 | * [Memo] |
11 | * |
12 | * Outbound: |
13 | * The compression of IP datagram MUST be done before AH/ESP processing, |
14 | * fragmentation, and the addition of Hop-by-Hop/Routing header. |
15 | * |
16 | * Inbound: |
17 | * The decompression of IP datagram MUST be done after the reassembly, |
18 | * AH/ESP processing. |
19 | */ |
20 | |
21 | #define pr_fmt(fmt) "IPv6: " fmt |
22 | |
23 | #include <linux/module.h> |
24 | #include <net/ip.h> |
25 | #include <net/xfrm.h> |
26 | #include <net/ipcomp.h> |
27 | #include <linux/crypto.h> |
28 | #include <linux/err.h> |
29 | #include <linux/pfkeyv2.h> |
30 | #include <linux/random.h> |
31 | #include <linux/percpu.h> |
32 | #include <linux/smp.h> |
33 | #include <linux/list.h> |
34 | #include <linux/vmalloc.h> |
35 | #include <linux/rtnetlink.h> |
36 | #include <net/ip6_route.h> |
37 | #include <net/icmp.h> |
38 | #include <net/ipv6.h> |
39 | #include <net/protocol.h> |
40 | #include <linux/ipv6.h> |
41 | #include <linux/icmpv6.h> |
42 | #include <linux/mutex.h> |
43 | |
44 | static int ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, |
45 | u8 type, u8 code, int offset, __be32 info) |
46 | { |
47 | struct net *net = dev_net(dev: skb->dev); |
48 | __be32 spi; |
49 | const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; |
50 | struct ip_comp_hdr *ipcomph = |
51 | (struct ip_comp_hdr *)(skb->data + offset); |
52 | struct xfrm_state *x; |
53 | |
54 | if (type != ICMPV6_PKT_TOOBIG && |
55 | type != NDISC_REDIRECT) |
56 | return 0; |
57 | |
58 | spi = htonl(ntohs(ipcomph->cpi)); |
59 | x = xfrm_state_lookup(net, mark: skb->mark, daddr: (const xfrm_address_t *)&iph->daddr, |
60 | spi, IPPROTO_COMP, AF_INET6); |
61 | if (!x) |
62 | return 0; |
63 | |
64 | if (type == NDISC_REDIRECT) |
65 | ip6_redirect(skb, net, oif: skb->dev->ifindex, mark: 0, |
66 | uid: sock_net_uid(net, NULL)); |
67 | else |
68 | ip6_update_pmtu(skb, net, mtu: info, oif: 0, mark: 0, uid: sock_net_uid(net, NULL)); |
69 | xfrm_state_put(x); |
70 | |
71 | return 0; |
72 | } |
73 | |
74 | static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) |
75 | { |
76 | struct net *net = xs_net(x); |
77 | struct xfrm_state *t = NULL; |
78 | |
79 | t = xfrm_state_alloc(net); |
80 | if (!t) |
81 | goto out; |
82 | |
83 | t->id.proto = IPPROTO_IPV6; |
84 | t->id.spi = xfrm6_tunnel_alloc_spi(net, saddr: (xfrm_address_t *)&x->props.saddr); |
85 | if (!t->id.spi) |
86 | goto error; |
87 | |
88 | memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); |
89 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); |
90 | t->props.family = AF_INET6; |
91 | t->props.mode = x->props.mode; |
92 | memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); |
93 | memcpy(&t->mark, &x->mark, sizeof(t->mark)); |
94 | t->if_id = x->if_id; |
95 | |
96 | if (xfrm_init_state(x: t)) |
97 | goto error; |
98 | |
99 | atomic_set(v: &t->tunnel_users, i: 1); |
100 | |
101 | out: |
102 | return t; |
103 | |
104 | error: |
105 | t->km.state = XFRM_STATE_DEAD; |
106 | xfrm_state_put(x: t); |
107 | t = NULL; |
108 | goto out; |
109 | } |
110 | |
111 | static int ipcomp6_tunnel_attach(struct xfrm_state *x) |
112 | { |
113 | struct net *net = xs_net(x); |
114 | int err = 0; |
115 | struct xfrm_state *t = NULL; |
116 | __be32 spi; |
117 | u32 mark = x->mark.m & x->mark.v; |
118 | |
119 | spi = xfrm6_tunnel_spi_lookup(net, saddr: (xfrm_address_t *)&x->props.saddr); |
120 | if (spi) |
121 | t = xfrm_state_lookup(net, mark, daddr: (xfrm_address_t *)&x->id.daddr, |
122 | spi, IPPROTO_IPV6, AF_INET6); |
123 | if (!t) { |
124 | t = ipcomp6_tunnel_create(x); |
125 | if (!t) { |
126 | err = -EINVAL; |
127 | goto out; |
128 | } |
129 | xfrm_state_insert(x: t); |
130 | xfrm_state_hold(x: t); |
131 | } |
132 | x->tunnel = t; |
133 | atomic_inc(v: &t->tunnel_users); |
134 | |
135 | out: |
136 | return err; |
137 | } |
138 | |
139 | static int ipcomp6_init_state(struct xfrm_state *x, |
140 | struct netlink_ext_ack *extack) |
141 | { |
142 | int err = -EINVAL; |
143 | |
144 | x->props.header_len = 0; |
145 | switch (x->props.mode) { |
146 | case XFRM_MODE_TRANSPORT: |
147 | break; |
148 | case XFRM_MODE_TUNNEL: |
149 | x->props.header_len += sizeof(struct ipv6hdr); |
150 | break; |
151 | default: |
152 | NL_SET_ERR_MSG(extack, "Unsupported XFRM mode for IPcomp" ); |
153 | goto out; |
154 | } |
155 | |
156 | err = ipcomp_init_state(x, extack); |
157 | if (err) |
158 | goto out; |
159 | |
160 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
161 | err = ipcomp6_tunnel_attach(x); |
162 | if (err) { |
163 | NL_SET_ERR_MSG(extack, "Kernel error: failed to initialize the associated state" ); |
164 | goto out; |
165 | } |
166 | } |
167 | |
168 | err = 0; |
169 | out: |
170 | return err; |
171 | } |
172 | |
173 | static int ipcomp6_rcv_cb(struct sk_buff *skb, int err) |
174 | { |
175 | return 0; |
176 | } |
177 | |
178 | static const struct xfrm_type ipcomp6_type = { |
179 | .owner = THIS_MODULE, |
180 | .proto = IPPROTO_COMP, |
181 | .init_state = ipcomp6_init_state, |
182 | .destructor = ipcomp_destroy, |
183 | .input = ipcomp_input, |
184 | .output = ipcomp_output, |
185 | }; |
186 | |
187 | static struct xfrm6_protocol ipcomp6_protocol = { |
188 | .handler = xfrm6_rcv, |
189 | .input_handler = xfrm_input, |
190 | .cb_handler = ipcomp6_rcv_cb, |
191 | .err_handler = ipcomp6_err, |
192 | .priority = 0, |
193 | }; |
194 | |
195 | static int __init ipcomp6_init(void) |
196 | { |
197 | if (xfrm_register_type(type: &ipcomp6_type, AF_INET6) < 0) { |
198 | pr_info("%s: can't add xfrm type\n" , __func__); |
199 | return -EAGAIN; |
200 | } |
201 | if (xfrm6_protocol_register(handler: &ipcomp6_protocol, IPPROTO_COMP) < 0) { |
202 | pr_info("%s: can't add protocol\n" , __func__); |
203 | xfrm_unregister_type(type: &ipcomp6_type, AF_INET6); |
204 | return -EAGAIN; |
205 | } |
206 | return 0; |
207 | } |
208 | |
209 | static void __exit ipcomp6_fini(void) |
210 | { |
211 | if (xfrm6_protocol_deregister(handler: &ipcomp6_protocol, IPPROTO_COMP) < 0) |
212 | pr_info("%s: can't remove protocol\n" , __func__); |
213 | xfrm_unregister_type(type: &ipcomp6_type, AF_INET6); |
214 | } |
215 | |
216 | module_init(ipcomp6_init); |
217 | module_exit(ipcomp6_fini); |
218 | MODULE_LICENSE("GPL" ); |
219 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173" ); |
220 | MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>" ); |
221 | |
222 | MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP); |
223 | |