Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf
[linux-2.6-microblaze.git] / net / ipv4 / ipcomp.c
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
22 static 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 */
56 static 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         t->if_id = x->if_id;
76
77         if (xfrm_init_state(t))
78                 goto error;
79
80         atomic_set(&t->tunnel_users, 1);
81 out:
82         return t;
83
84 error:
85         t->km.state = XFRM_STATE_DEAD;
86         xfrm_state_put(t);
87         t = NULL;
88         goto out;
89 }
90
91 /*
92  * Must be protected by xfrm_cfg_mutex.  State and tunnel user references are
93  * always incremented on success.
94  */
95 static int ipcomp_tunnel_attach(struct xfrm_state *x)
96 {
97         struct net *net = xs_net(x);
98         int err = 0;
99         struct xfrm_state *t;
100         u32 mark = x->mark.v & x->mark.m;
101
102         t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
103                               x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
104         if (!t) {
105                 t = ipcomp_tunnel_create(x);
106                 if (!t) {
107                         err = -EINVAL;
108                         goto out;
109                 }
110                 xfrm_state_insert(t);
111                 xfrm_state_hold(t);
112         }
113         x->tunnel = t;
114         atomic_inc(&t->tunnel_users);
115 out:
116         return err;
117 }
118
119 static int ipcomp4_init_state(struct xfrm_state *x)
120 {
121         int err = -EINVAL;
122
123         x->props.header_len = 0;
124         switch (x->props.mode) {
125         case XFRM_MODE_TRANSPORT:
126                 break;
127         case XFRM_MODE_TUNNEL:
128                 x->props.header_len += sizeof(struct iphdr);
129                 break;
130         default:
131                 goto out;
132         }
133
134         err = ipcomp_init_state(x);
135         if (err)
136                 goto out;
137
138         if (x->props.mode == XFRM_MODE_TUNNEL) {
139                 err = ipcomp_tunnel_attach(x);
140                 if (err)
141                         goto out;
142         }
143
144         err = 0;
145 out:
146         return err;
147 }
148
149 static int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
150 {
151         return 0;
152 }
153
154 static const struct xfrm_type ipcomp_type = {
155         .description    = "IPCOMP4",
156         .owner          = THIS_MODULE,
157         .proto          = IPPROTO_COMP,
158         .init_state     = ipcomp4_init_state,
159         .destructor     = ipcomp_destroy,
160         .input          = ipcomp_input,
161         .output         = ipcomp_output
162 };
163
164 static struct xfrm4_protocol ipcomp4_protocol = {
165         .handler        =       xfrm4_rcv,
166         .input_handler  =       xfrm_input,
167         .cb_handler     =       ipcomp4_rcv_cb,
168         .err_handler    =       ipcomp4_err,
169         .priority       =       0,
170 };
171
172 static int __init ipcomp4_init(void)
173 {
174         if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
175                 pr_info("%s: can't add xfrm type\n", __func__);
176                 return -EAGAIN;
177         }
178         if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
179                 pr_info("%s: can't add protocol\n", __func__);
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 {
188         if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0)
189                 pr_info("%s: can't remove protocol\n", __func__);
190         xfrm_unregister_type(&ipcomp_type, AF_INET);
191 }
192
193 module_init(ipcomp4_init);
194 module_exit(ipcomp4_fini);
195
196 MODULE_LICENSE("GPL");
197 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
198 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
199
200 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);