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 34 #define pr_fmt(fmt) "IPv6: " fmt 35 36 #include <linux/module.h> 37 #include <net/ip.h> 38 #include <net/xfrm.h> 39 #include <net/ipcomp.h> 40 #include <linux/crypto.h> 41 #include <linux/err.h> 42 #include <linux/pfkeyv2.h> 43 #include <linux/random.h> 44 #include <linux/percpu.h> 45 #include <linux/smp.h> 46 #include <linux/list.h> 47 #include <linux/vmalloc.h> 48 #include <linux/rtnetlink.h> 49 #include <net/icmp.h> 50 #include <net/ipv6.h> 51 #include <net/protocol.h> 52 #include <linux/ipv6.h> 53 #include <linux/icmpv6.h> 54 #include <linux/mutex.h> 55 56 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 57 u8 type, u8 code, int offset, __be32 info) 58 { 59 struct net *net = dev_net(skb->dev); 60 __be32 spi; 61 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 62 struct ip_comp_hdr *ipcomph = 63 (struct ip_comp_hdr *)(skb->data + offset); 64 struct xfrm_state *x; 65 66 if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG) 67 return; 68 69 spi = htonl(ntohs(ipcomph->cpi)); 70 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 71 spi, IPPROTO_COMP, AF_INET6); 72 if (!x) 73 return; 74 75 pr_debug("pmtu discovery on SA IPCOMP/%08x/%pI6\n", 76 spi, &iph->daddr); 77 xfrm_state_put(x); 78 } 79 80 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) 81 { 82 struct net *net = xs_net(x); 83 struct xfrm_state *t = NULL; 84 85 t = xfrm_state_alloc(net); 86 if (!t) 87 goto out; 88 89 t->id.proto = IPPROTO_IPV6; 90 t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr); 91 if (!t->id.spi) 92 goto error; 93 94 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); 95 memcpy(&t->sel, &x->sel, sizeof(t->sel)); 96 t->props.family = AF_INET6; 97 t->props.mode = x->props.mode; 98 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); 99 memcpy(&t->mark, &x->mark, sizeof(t->mark)); 100 101 if (xfrm_init_state(t)) 102 goto error; 103 104 atomic_set(&t->tunnel_users, 1); 105 106 out: 107 return t; 108 109 error: 110 t->km.state = XFRM_STATE_DEAD; 111 xfrm_state_put(t); 112 t = NULL; 113 goto out; 114 } 115 116 static int ipcomp6_tunnel_attach(struct xfrm_state *x) 117 { 118 struct net *net = xs_net(x); 119 int err = 0; 120 struct xfrm_state *t = NULL; 121 __be32 spi; 122 u32 mark = x->mark.m & x->mark.v; 123 124 spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr); 125 if (spi) 126 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr, 127 spi, IPPROTO_IPV6, AF_INET6); 128 if (!t) { 129 t = ipcomp6_tunnel_create(x); 130 if (!t) { 131 err = -EINVAL; 132 goto out; 133 } 134 xfrm_state_insert(t); 135 xfrm_state_hold(t); 136 } 137 x->tunnel = t; 138 atomic_inc(&t->tunnel_users); 139 140 out: 141 return err; 142 } 143 144 static int ipcomp6_init_state(struct xfrm_state *x) 145 { 146 int err = -EINVAL; 147 148 x->props.header_len = 0; 149 switch (x->props.mode) { 150 case XFRM_MODE_TRANSPORT: 151 break; 152 case XFRM_MODE_TUNNEL: 153 x->props.header_len += sizeof(struct ipv6hdr); 154 break; 155 default: 156 goto out; 157 } 158 159 err = ipcomp_init_state(x); 160 if (err) 161 goto out; 162 163 if (x->props.mode == XFRM_MODE_TUNNEL) { 164 err = ipcomp6_tunnel_attach(x); 165 if (err) 166 goto out; 167 } 168 169 err = 0; 170 out: 171 return err; 172 } 173 174 static const struct xfrm_type ipcomp6_type = 175 { 176 .description = "IPCOMP6", 177 .owner = THIS_MODULE, 178 .proto = IPPROTO_COMP, 179 .init_state = ipcomp6_init_state, 180 .destructor = ipcomp_destroy, 181 .input = ipcomp_input, 182 .output = ipcomp_output, 183 .hdr_offset = xfrm6_find_1stfragopt, 184 }; 185 186 static const struct inet6_protocol ipcomp6_protocol = 187 { 188 .handler = xfrm6_rcv, 189 .err_handler = ipcomp6_err, 190 .flags = INET6_PROTO_NOPOLICY, 191 }; 192 193 static int __init ipcomp6_init(void) 194 { 195 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { 196 pr_info("%s: can't add xfrm type\n", __func__); 197 return -EAGAIN; 198 } 199 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) { 200 pr_info("%s: can't add protocol\n", __func__); 201 xfrm_unregister_type(&ipcomp6_type, AF_INET6); 202 return -EAGAIN; 203 } 204 return 0; 205 } 206 207 static void __exit ipcomp6_fini(void) 208 { 209 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) 210 pr_info("%s: can't remove protocol\n", __func__); 211 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) 212 pr_info("%s: can't remove xfrm type\n", __func__); 213 } 214 215 module_init(ipcomp6_init); 216 module_exit(ipcomp6_fini); 217 MODULE_LICENSE("GPL"); 218 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); 219 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); 220 221 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP); 222