1 /* 2 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173 3 * 4 * Copyright (C)2003 USAGI/WIDE Project 5 * 6 * Author Mitsuru KANDA <mk@linux-ipv6.org> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21 */ 22 /* 23 * [Memo] 24 * 25 * Outbound: 26 * The compression of IP datagram MUST be done before AH/ESP processing, 27 * fragmentation, and the addition of Hop-by-Hop/Routing header. 28 * 29 * Inbound: 30 * The decompression of IP datagram MUST be done after the reassembly, 31 * AH/ESP processing. 32 */ 33 #include <linux/module.h> 34 #include <net/ip.h> 35 #include <net/xfrm.h> 36 #include <net/ipcomp.h> 37 #include <linux/crypto.h> 38 #include <linux/err.h> 39 #include <linux/pfkeyv2.h> 40 #include <linux/random.h> 41 #include <linux/percpu.h> 42 #include <linux/smp.h> 43 #include <linux/list.h> 44 #include <linux/vmalloc.h> 45 #include <linux/rtnetlink.h> 46 #include <net/icmp.h> 47 #include <net/ipv6.h> 48 #include <net/protocol.h> 49 #include <linux/ipv6.h> 50 #include <linux/icmpv6.h> 51 #include <linux/mutex.h> 52 53 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 54 int type, int code, int offset, __be32 info) 55 { 56 __be32 spi; 57 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; 58 struct ip_comp_hdr *ipcomph = 59 (struct ip_comp_hdr *)(skb->data + offset); 60 struct xfrm_state *x; 61 62 if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG) 63 return; 64 65 spi = htonl(ntohs(ipcomph->cpi)); 66 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6); 67 if (!x) 68 return; 69 70 printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n", 71 spi, NIP6(iph->daddr)); 72 xfrm_state_put(x); 73 } 74 75 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) 76 { 77 struct xfrm_state *t = NULL; 78 79 t = xfrm_state_alloc(); 80 if (!t) 81 goto out; 82 83 t->id.proto = IPPROTO_IPV6; 84 t->id.spi = xfrm6_tunnel_alloc_spi((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 94 if (xfrm_init_state(t)) 95 goto error; 96 97 atomic_set(&t->tunnel_users, 1); 98 99 out: 100 return t; 101 102 error: 103 t->km.state = XFRM_STATE_DEAD; 104 xfrm_state_put(t); 105 t = NULL; 106 goto out; 107 } 108 109 static int ipcomp6_tunnel_attach(struct xfrm_state *x) 110 { 111 int err = 0; 112 struct xfrm_state *t = NULL; 113 __be32 spi; 114 115 spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr); 116 if (spi) 117 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr, 118 spi, IPPROTO_IPV6, AF_INET6); 119 if (!t) { 120 t = ipcomp6_tunnel_create(x); 121 if (!t) { 122 err = -EINVAL; 123 goto out; 124 } 125 xfrm_state_insert(t); 126 xfrm_state_hold(t); 127 } 128 x->tunnel = t; 129 atomic_inc(&t->tunnel_users); 130 131 out: 132 return err; 133 } 134 135 static int ipcomp6_init_state(struct xfrm_state *x) 136 { 137 int err = -EINVAL; 138 139 x->props.header_len = 0; 140 switch (x->props.mode) { 141 case XFRM_MODE_TRANSPORT: 142 break; 143 case XFRM_MODE_TUNNEL: 144 x->props.header_len += sizeof(struct ipv6hdr); 145 break; 146 default: 147 goto out; 148 } 149 150 err = ipcomp_init_state(x); 151 if (err) 152 goto out; 153 154 if (x->props.mode == XFRM_MODE_TUNNEL) { 155 err = ipcomp6_tunnel_attach(x); 156 if (err) 157 goto error_tunnel; 158 } 159 160 err = 0; 161 out: 162 return err; 163 error_tunnel: 164 ipcomp_destroy(x); 165 166 goto out; 167 } 168 169 static const struct xfrm_type ipcomp6_type = 170 { 171 .description = "IPCOMP6", 172 .owner = THIS_MODULE, 173 .proto = IPPROTO_COMP, 174 .init_state = ipcomp6_init_state, 175 .destructor = ipcomp_destroy, 176 .input = ipcomp_input, 177 .output = ipcomp_output, 178 .hdr_offset = xfrm6_find_1stfragopt, 179 }; 180 181 static struct inet6_protocol ipcomp6_protocol = 182 { 183 .handler = xfrm6_rcv, 184 .err_handler = ipcomp6_err, 185 .flags = INET6_PROTO_NOPOLICY, 186 }; 187 188 static int __init ipcomp6_init(void) 189 { 190 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { 191 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n"); 192 return -EAGAIN; 193 } 194 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) { 195 printk(KERN_INFO "ipcomp6 init: can't add protocol\n"); 196 xfrm_unregister_type(&ipcomp6_type, AF_INET6); 197 return -EAGAIN; 198 } 199 return 0; 200 } 201 202 static void __exit ipcomp6_fini(void) 203 { 204 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) 205 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n"); 206 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) 207 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n"); 208 } 209 210 module_init(ipcomp6_init); 211 module_exit(ipcomp6_fini); 212 MODULE_LICENSE("GPL"); 213 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); 214 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); 215 216 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP); 217