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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * IP Payload Compression Protocol (IPComp) - RFC3173. | |
4 | * | |
5 | * Copyright (c) 2003 James Morris <jmorris@intercode.com.au> | |
6 | * | |
1da177e4 LT |
7 | * Todo: |
8 | * - Tunable compression parameters. | |
9 | * - Compression stats. | |
10 | * - Adaptive compression. | |
11 | */ | |
1da177e4 | 12 | #include <linux/module.h> |
4999f362 | 13 | #include <linux/err.h> |
1da177e4 LT |
14 | #include <linux/rtnetlink.h> |
15 | #include <net/ip.h> | |
16 | #include <net/xfrm.h> | |
17 | #include <net/icmp.h> | |
18 | #include <net/ipcomp.h> | |
14c85021 | 19 | #include <net/protocol.h> |
6fccab67 | 20 | #include <net/sock.h> |
1da177e4 | 21 | |
d099160e | 22 | static int ipcomp4_err(struct sk_buff *skb, u32 info) |
1da177e4 | 23 | { |
a92df254 | 24 | struct net *net = dev_net(skb->dev); |
a94cfd19 | 25 | __be32 spi; |
b71d1d42 | 26 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
1da177e4 LT |
27 | struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); |
28 | struct xfrm_state *x; | |
29 | ||
55be7a9c DM |
30 | switch (icmp_hdr(skb)->type) { |
31 | case ICMP_DEST_UNREACH: | |
32 | if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) | |
d099160e | 33 | return 0; |
79121184 | 34 | break; |
55be7a9c DM |
35 | case ICMP_REDIRECT: |
36 | break; | |
37 | default: | |
d099160e | 38 | return 0; |
55be7a9c | 39 | } |
1da177e4 | 40 | |
4195f814 | 41 | spi = htonl(ntohs(ipch->cpi)); |
b71d1d42 | 42 | x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, |
e905a9ed | 43 | spi, IPPROTO_COMP, AF_INET); |
1da177e4 | 44 | if (!x) |
d099160e | 45 | return 0; |
55be7a9c | 46 | |
387aa65a | 47 | if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) |
d888f396 | 48 | ipv4_update_pmtu(skb, net, info, 0, IPPROTO_COMP); |
387aa65a | 49 | else |
1042caa7 | 50 | ipv4_redirect(skb, net, 0, IPPROTO_COMP); |
1da177e4 | 51 | xfrm_state_put(x); |
d099160e SK |
52 | |
53 | return 0; | |
1da177e4 LT |
54 | } |
55 | ||
e905a9ed | 56 | /* We always hold one tunnel user reference to indicate a tunnel */ |
1da177e4 LT |
57 | static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x) |
58 | { | |
a92df254 | 59 | struct net *net = xs_net(x); |
1da177e4 | 60 | struct xfrm_state *t; |
e905a9ed | 61 | |
a92df254 | 62 | t = xfrm_state_alloc(net); |
51456b29 | 63 | if (!t) |
1da177e4 LT |
64 | goto out; |
65 | ||
66 | t->id.proto = IPPROTO_IPIP; | |
67 | t->id.spi = x->props.saddr.a4; | |
68 | t->id.daddr.a4 = x->id.daddr.a4; | |
69 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
70 | t->props.family = AF_INET; | |
e40b3286 | 71 | t->props.mode = x->props.mode; |
1da177e4 LT |
72 | t->props.saddr.a4 = x->props.saddr.a4; |
73 | t->props.flags = x->props.flags; | |
a947b0a9 | 74 | t->props.extra_flags = x->props.extra_flags; |
bd55775c | 75 | memcpy(&t->mark, &x->mark, sizeof(t->mark)); |
d5a7a505 | 76 | t->if_id = x->if_id; |
72cb6962 HX |
77 | |
78 | if (xfrm_init_state(t)) | |
1da177e4 LT |
79 | goto error; |
80 | ||
1da177e4 LT |
81 | atomic_set(&t->tunnel_users, 1); |
82 | out: | |
83 | return t; | |
84 | ||
85 | error: | |
86 | t->km.state = XFRM_STATE_DEAD; | |
87 | xfrm_state_put(t); | |
88 | t = NULL; | |
89 | goto out; | |
90 | } | |
91 | ||
92 | /* | |
4a3e2f71 | 93 | * Must be protected by xfrm_cfg_mutex. State and tunnel user references are |
1da177e4 LT |
94 | * always incremented on success. |
95 | */ | |
96 | static int ipcomp_tunnel_attach(struct xfrm_state *x) | |
97 | { | |
a92df254 | 98 | struct net *net = xs_net(x); |
1da177e4 LT |
99 | int err = 0; |
100 | struct xfrm_state *t; | |
bd55775c | 101 | u32 mark = x->mark.v & x->mark.m; |
1da177e4 | 102 | |
bd55775c | 103 | t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4, |
e905a9ed | 104 | x->props.saddr.a4, IPPROTO_IPIP, AF_INET); |
1da177e4 LT |
105 | if (!t) { |
106 | t = ipcomp_tunnel_create(x); | |
107 | if (!t) { | |
108 | err = -EINVAL; | |
109 | goto out; | |
110 | } | |
111 | xfrm_state_insert(t); | |
112 | xfrm_state_hold(t); | |
113 | } | |
114 | x->tunnel = t; | |
115 | atomic_inc(&t->tunnel_users); | |
116 | out: | |
117 | return err; | |
118 | } | |
119 | ||
6fccab67 | 120 | static int ipcomp4_init_state(struct xfrm_state *x) |
1da177e4 | 121 | { |
2c3abab7 | 122 | int err = -EINVAL; |
1da177e4 | 123 | |
e40b3286 HX |
124 | x->props.header_len = 0; |
125 | switch (x->props.mode) { | |
126 | case XFRM_MODE_TRANSPORT: | |
127 | break; | |
128 | case XFRM_MODE_TUNNEL: | |
129 | x->props.header_len += sizeof(struct iphdr); | |
130 | break; | |
131 | default: | |
132 | goto out; | |
133 | } | |
134 | ||
6fccab67 HX |
135 | err = ipcomp_init_state(x); |
136 | if (err) | |
1da177e4 LT |
137 | goto out; |
138 | ||
7e49e6de | 139 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
1da177e4 LT |
140 | err = ipcomp_tunnel_attach(x); |
141 | if (err) | |
10e7454e | 142 | goto out; |
1da177e4 LT |
143 | } |
144 | ||
1da177e4 LT |
145 | err = 0; |
146 | out: | |
147 | return err; | |
1da177e4 LT |
148 | } |
149 | ||
d099160e SK |
150 | static int ipcomp4_rcv_cb(struct sk_buff *skb, int err) |
151 | { | |
152 | return 0; | |
153 | } | |
154 | ||
533cb5b0 | 155 | static const struct xfrm_type ipcomp_type = { |
1da177e4 LT |
156 | .owner = THIS_MODULE, |
157 | .proto = IPPROTO_COMP, | |
6fccab67 | 158 | .init_state = ipcomp4_init_state, |
1da177e4 LT |
159 | .destructor = ipcomp_destroy, |
160 | .input = ipcomp_input, | |
161 | .output = ipcomp_output | |
162 | }; | |
163 | ||
d099160e | 164 | static struct xfrm4_protocol ipcomp4_protocol = { |
1da177e4 | 165 | .handler = xfrm4_rcv, |
d099160e SK |
166 | .input_handler = xfrm_input, |
167 | .cb_handler = ipcomp4_rcv_cb, | |
1da177e4 | 168 | .err_handler = ipcomp4_err, |
d099160e | 169 | .priority = 0, |
1da177e4 LT |
170 | }; |
171 | ||
172 | static int __init ipcomp4_init(void) | |
173 | { | |
174 | if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) { | |
058bd4d2 | 175 | pr_info("%s: can't add xfrm type\n", __func__); |
1da177e4 LT |
176 | return -EAGAIN; |
177 | } | |
d099160e | 178 | if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) { |
058bd4d2 | 179 | pr_info("%s: can't add protocol\n", __func__); |
1da177e4 LT |
180 | xfrm_unregister_type(&ipcomp_type, AF_INET); |
181 | return -EAGAIN; | |
182 | } | |
183 | return 0; | |
184 | } | |
185 | ||
186 | static void __exit ipcomp4_fini(void) | |
187 | { | |
d099160e | 188 | if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0) |
058bd4d2 | 189 | pr_info("%s: can't remove protocol\n", __func__); |
4f518e80 | 190 | xfrm_unregister_type(&ipcomp_type, AF_INET); |
1da177e4 LT |
191 | } |
192 | ||
193 | module_init(ipcomp4_init); | |
194 | module_exit(ipcomp4_fini); | |
195 | ||
196 | MODULE_LICENSE("GPL"); | |
6fccab67 | 197 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173"); |
1da177e4 LT |
198 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); |
199 | ||
d3d6dd3a | 200 | MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP); |