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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IP Payload Compression Protocol (IPComp) - RFC3173.
4 *
5 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
6 *
7 * Todo:
8 * - Tunable compression parameters.
9 * - Compression stats.
10 * - Adaptive compression.
11 */
12#include <linux/module.h>
13#include <linux/err.h>
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>
19#include <net/protocol.h>
20#include <net/sock.h>
21
22static int ipcomp4_err(struct sk_buff *skb, u32 info)
23{
24 struct net *net = dev_net(skb->dev);
25 __be32 spi;
26 const struct iphdr *iph = (const struct iphdr *)skb->data;
27 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
28 struct xfrm_state *x;
29
30 switch (icmp_hdr(skb)->type) {
31 case ICMP_DEST_UNREACH:
32 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
33 return 0;
34 case ICMP_REDIRECT:
35 break;
36 default:
37 return 0;
38 }
39
40 spi = htonl(ntohs(ipch->cpi));
41 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
42 spi, IPPROTO_COMP, AF_INET);
43 if (!x)
44 return 0;
45
46 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
47 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_COMP);
48 else
49 ipv4_redirect(skb, net, 0, IPPROTO_COMP);
50 xfrm_state_put(x);
51
52 return 0;
53}
54
55/* We always hold one tunnel user reference to indicate a tunnel */
56static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
57{
58 struct net *net = xs_net(x);
59 struct xfrm_state *t;
60
61 t = xfrm_state_alloc(net);
62 if (!t)
63 goto out;
64
65 t->id.proto = IPPROTO_IPIP;
66 t->id.spi = x->props.saddr.a4;
67 t->id.daddr.a4 = x->id.daddr.a4;
68 memcpy(&t->sel, &x->sel, sizeof(t->sel));
69 t->props.family = AF_INET;
70 t->props.mode = x->props.mode;
71 t->props.saddr.a4 = x->props.saddr.a4;
72 t->props.flags = x->props.flags;
73 t->props.extra_flags = x->props.extra_flags;
74 memcpy(&t->mark, &x->mark, sizeof(t->mark));
75
76 if (xfrm_init_state(t))
77 goto error;
78
79 atomic_set(&t->tunnel_users, 1);
80out:
81 return t;
82
83error:
84 t->km.state = XFRM_STATE_DEAD;
85 xfrm_state_put(t);
86 t = NULL;
87 goto out;
88}
89
90/*
91 * Must be protected by xfrm_cfg_mutex. State and tunnel user references are
92 * always incremented on success.
93 */
94static int ipcomp_tunnel_attach(struct xfrm_state *x)
95{
96 struct net *net = xs_net(x);
97 int err = 0;
98 struct xfrm_state *t;
99 u32 mark = x->mark.v & x->mark.m;
100
101 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
102 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
103 if (!t) {
104 t = ipcomp_tunnel_create(x);
105 if (!t) {
106 err = -EINVAL;
107 goto out;
108 }
109 xfrm_state_insert(t);
110 xfrm_state_hold(t);
111 }
112 x->tunnel = t;
113 atomic_inc(&t->tunnel_users);
114out:
115 return err;
116}
117
118static int ipcomp4_init_state(struct xfrm_state *x)
119{
120 int err = -EINVAL;
121
122 x->props.header_len = 0;
123 switch (x->props.mode) {
124 case XFRM_MODE_TRANSPORT:
125 break;
126 case XFRM_MODE_TUNNEL:
127 x->props.header_len += sizeof(struct iphdr);
128 break;
129 default:
130 goto out;
131 }
132
133 err = ipcomp_init_state(x);
134 if (err)
135 goto out;
136
137 if (x->props.mode == XFRM_MODE_TUNNEL) {
138 err = ipcomp_tunnel_attach(x);
139 if (err)
140 goto out;
141 }
142
143 err = 0;
144out:
145 return err;
146}
147
148static int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
149{
150 return 0;
151}
152
153static const struct xfrm_type ipcomp_type = {
154 .description = "IPCOMP4",
155 .owner = THIS_MODULE,
156 .proto = IPPROTO_COMP,
157 .init_state = ipcomp4_init_state,
158 .destructor = ipcomp_destroy,
159 .input = ipcomp_input,
160 .output = ipcomp_output
161};
162
163static struct xfrm4_protocol ipcomp4_protocol = {
164 .handler = xfrm4_rcv,
165 .input_handler = xfrm_input,
166 .cb_handler = ipcomp4_rcv_cb,
167 .err_handler = ipcomp4_err,
168 .priority = 0,
169};
170
171static int __init ipcomp4_init(void)
172{
173 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
174 pr_info("%s: can't add xfrm type\n", __func__);
175 return -EAGAIN;
176 }
177 if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
178 pr_info("%s: can't add protocol\n", __func__);
179 xfrm_unregister_type(&ipcomp_type, AF_INET);
180 return -EAGAIN;
181 }
182 return 0;
183}
184
185static void __exit ipcomp4_fini(void)
186{
187 if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0)
188 pr_info("%s: can't remove protocol\n", __func__);
189 xfrm_unregister_type(&ipcomp_type, AF_INET);
190}
191
192module_init(ipcomp4_init);
193module_exit(ipcomp4_fini);
194
195MODULE_LICENSE("GPL");
196MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
197MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
198
199MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IP Payload Compression Protocol (IPComp) - RFC3173.
4 *
5 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
6 *
7 * Todo:
8 * - Tunable compression parameters.
9 * - Compression stats.
10 * - Adaptive compression.
11 */
12#include <linux/module.h>
13#include <linux/err.h>
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>
19#include <net/protocol.h>
20#include <net/sock.h>
21
22static int ipcomp4_err(struct sk_buff *skb, u32 info)
23{
24 struct net *net = dev_net(skb->dev);
25 __be32 spi;
26 const struct iphdr *iph = (const struct iphdr *)skb->data;
27 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
28 struct xfrm_state *x;
29
30 switch (icmp_hdr(skb)->type) {
31 case ICMP_DEST_UNREACH:
32 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
33 return 0;
34 break;
35 case ICMP_REDIRECT:
36 break;
37 default:
38 return 0;
39 }
40
41 spi = htonl(ntohs(ipch->cpi));
42 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
43 spi, IPPROTO_COMP, AF_INET);
44 if (!x)
45 return 0;
46
47 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
48 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_COMP);
49 else
50 ipv4_redirect(skb, net, 0, IPPROTO_COMP);
51 xfrm_state_put(x);
52
53 return 0;
54}
55
56/* We always hold one tunnel user reference to indicate a tunnel */
57static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
58{
59 struct net *net = xs_net(x);
60 struct xfrm_state *t;
61
62 t = xfrm_state_alloc(net);
63 if (!t)
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;
71 t->props.mode = x->props.mode;
72 t->props.saddr.a4 = x->props.saddr.a4;
73 t->props.flags = x->props.flags;
74 t->props.extra_flags = x->props.extra_flags;
75 memcpy(&t->mark, &x->mark, sizeof(t->mark));
76 t->if_id = x->if_id;
77
78 if (xfrm_init_state(t))
79 goto error;
80
81 atomic_set(&t->tunnel_users, 1);
82out:
83 return t;
84
85error:
86 t->km.state = XFRM_STATE_DEAD;
87 xfrm_state_put(t);
88 t = NULL;
89 goto out;
90}
91
92/*
93 * Must be protected by xfrm_cfg_mutex. State and tunnel user references are
94 * always incremented on success.
95 */
96static int ipcomp_tunnel_attach(struct xfrm_state *x)
97{
98 struct net *net = xs_net(x);
99 int err = 0;
100 struct xfrm_state *t;
101 u32 mark = x->mark.v & x->mark.m;
102
103 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
104 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
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);
116out:
117 return err;
118}
119
120static int ipcomp4_init_state(struct xfrm_state *x,
121 struct netlink_ext_ack *extack)
122{
123 int err = -EINVAL;
124
125 x->props.header_len = 0;
126 switch (x->props.mode) {
127 case XFRM_MODE_TRANSPORT:
128 break;
129 case XFRM_MODE_TUNNEL:
130 x->props.header_len += sizeof(struct iphdr);
131 break;
132 default:
133 NL_SET_ERR_MSG(extack, "Unsupported XFRM mode for IPcomp");
134 goto out;
135 }
136
137 err = ipcomp_init_state(x, extack);
138 if (err)
139 goto out;
140
141 if (x->props.mode == XFRM_MODE_TUNNEL) {
142 err = ipcomp_tunnel_attach(x);
143 if (err) {
144 NL_SET_ERR_MSG(extack, "Kernel error: failed to initialize the associated state");
145 goto out;
146 }
147 }
148
149 err = 0;
150out:
151 return err;
152}
153
154static int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
155{
156 return 0;
157}
158
159static const struct xfrm_type ipcomp_type = {
160 .owner = THIS_MODULE,
161 .proto = IPPROTO_COMP,
162 .init_state = ipcomp4_init_state,
163 .destructor = ipcomp_destroy,
164 .input = ipcomp_input,
165 .output = ipcomp_output
166};
167
168static struct xfrm4_protocol ipcomp4_protocol = {
169 .handler = xfrm4_rcv,
170 .input_handler = xfrm_input,
171 .cb_handler = ipcomp4_rcv_cb,
172 .err_handler = ipcomp4_err,
173 .priority = 0,
174};
175
176static int __init ipcomp4_init(void)
177{
178 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
179 pr_info("%s: can't add xfrm type\n", __func__);
180 return -EAGAIN;
181 }
182 if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
183 pr_info("%s: can't add protocol\n", __func__);
184 xfrm_unregister_type(&ipcomp_type, AF_INET);
185 return -EAGAIN;
186 }
187 return 0;
188}
189
190static void __exit ipcomp4_fini(void)
191{
192 if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0)
193 pr_info("%s: can't remove protocol\n", __func__);
194 xfrm_unregister_type(&ipcomp_type, AF_INET);
195}
196
197module_init(ipcomp4_init);
198module_exit(ipcomp4_fini);
199
200MODULE_LICENSE("GPL");
201MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
202MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
203
204MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);