1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173 4 * 5 * Copyright (C)2003 USAGI/WIDE Project 6 * 7 * Author Mitsuru KANDA <mk@linux-ipv6.org> 8 */ 9 /* 10 * [Memo] 11 * 12 * Outbound: 13 * The compression of IP datagram MUST be done before AH/ESP processing, 14 * fragmentation, and the addition of Hop-by-Hop/Routing header. 15 * 16 * Inbound: 17 * The decompression of IP datagram MUST be done after the reassembly, 18 * AH/ESP processing. 19 */ 20 21 #define pr_fmt(fmt) "IPv6: " fmt 22 23 #include <linux/module.h> 24 #include <net/ip.h> 25 #include <net/xfrm.h> 26 #include <net/ipcomp.h> 27 #include <linux/crypto.h> 28 #include <linux/err.h> 29 #include <linux/pfkeyv2.h> 30 #include <linux/random.h> 31 #include <linux/percpu.h> 32 #include <linux/smp.h> 33 #include <linux/list.h> 34 #include <linux/vmalloc.h> 35 #include <linux/rtnetlink.h> 36 #include <net/ip6_route.h> 37 #include <net/icmp.h> 38 #include <net/ipv6.h> 39 #include <net/protocol.h> 40 #include <linux/ipv6.h> 41 #include <linux/icmpv6.h> 42 #include <linux/mutex.h> 43 44 static int ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 45 u8 type, u8 code, int offset, __be32 info) 46 { 47 struct net *net = dev_net(skb->dev); 48 __be32 spi; 49 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 50 struct ip_comp_hdr *ipcomph = 51 (struct ip_comp_hdr *)(skb->data + offset); 52 struct xfrm_state *x; 53 54 if (type != ICMPV6_PKT_TOOBIG && 55 type != NDISC_REDIRECT) 56 return 0; 57 58 spi = htonl(ntohs(ipcomph->cpi)); 59 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 60 spi, IPPROTO_COMP, AF_INET6); 61 if (!x) 62 return 0; 63 64 if (type == NDISC_REDIRECT) 65 ip6_redirect(skb, net, skb->dev->ifindex, 0, 66 sock_net_uid(net, NULL)); 67 else 68 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 69 xfrm_state_put(x); 70 71 return 0; 72 } 73 74 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) 75 { 76 struct net *net = xs_net(x); 77 struct xfrm_state *t = NULL; 78 79 t = xfrm_state_alloc(net); 80 if (!t) 81 goto out; 82 83 t->id.proto = IPPROTO_IPV6; 84 t->id.spi = xfrm6_tunnel_alloc_spi(net, (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 memcpy(&t->mark, &x->mark, sizeof(t->mark)); 94 t->if_id = x->if_id; 95 96 if (xfrm_init_state(t)) 97 goto error; 98 99 atomic_set(&t->tunnel_users, 1); 100 101 out: 102 return t; 103 104 error: 105 t->km.state = XFRM_STATE_DEAD; 106 xfrm_state_put(t); 107 t = NULL; 108 goto out; 109 } 110 111 static int ipcomp6_tunnel_attach(struct xfrm_state *x) 112 { 113 struct net *net = xs_net(x); 114 int err = 0; 115 struct xfrm_state *t = NULL; 116 __be32 spi; 117 u32 mark = x->mark.m & x->mark.v; 118 119 spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr); 120 if (spi) 121 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr, 122 spi, IPPROTO_IPV6, AF_INET6); 123 if (!t) { 124 t = ipcomp6_tunnel_create(x); 125 if (!t) { 126 err = -EINVAL; 127 goto out; 128 } 129 xfrm_state_insert(t); 130 xfrm_state_hold(t); 131 } 132 x->tunnel = t; 133 atomic_inc(&t->tunnel_users); 134 135 out: 136 return err; 137 } 138 139 static int ipcomp6_init_state(struct xfrm_state *x, 140 struct netlink_ext_ack *extack) 141 { 142 int err = -EINVAL; 143 144 x->props.header_len = 0; 145 switch (x->props.mode) { 146 case XFRM_MODE_TRANSPORT: 147 break; 148 case XFRM_MODE_TUNNEL: 149 x->props.header_len += sizeof(struct ipv6hdr); 150 break; 151 default: 152 NL_SET_ERR_MSG(extack, "Unsupported XFRM mode for IPcomp"); 153 goto out; 154 } 155 156 err = ipcomp_init_state(x, extack); 157 if (err) 158 goto out; 159 160 if (x->props.mode == XFRM_MODE_TUNNEL) { 161 err = ipcomp6_tunnel_attach(x); 162 if (err) { 163 NL_SET_ERR_MSG(extack, "Kernel error: failed to initialize the associated state"); 164 goto out; 165 } 166 } 167 168 err = 0; 169 out: 170 return err; 171 } 172 173 static int ipcomp6_rcv_cb(struct sk_buff *skb, int err) 174 { 175 return 0; 176 } 177 178 static const struct xfrm_type ipcomp6_type = { 179 .owner = THIS_MODULE, 180 .proto = IPPROTO_COMP, 181 .init_state = ipcomp6_init_state, 182 .destructor = ipcomp_destroy, 183 .input = ipcomp_input, 184 .output = ipcomp_output, 185 }; 186 187 static struct xfrm6_protocol ipcomp6_protocol = { 188 .handler = xfrm6_rcv, 189 .input_handler = xfrm_input, 190 .cb_handler = ipcomp6_rcv_cb, 191 .err_handler = ipcomp6_err, 192 .priority = 0, 193 }; 194 195 static int __init ipcomp6_init(void) 196 { 197 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { 198 pr_info("%s: can't add xfrm type\n", __func__); 199 return -EAGAIN; 200 } 201 if (xfrm6_protocol_register(&ipcomp6_protocol, IPPROTO_COMP) < 0) { 202 pr_info("%s: can't add protocol\n", __func__); 203 xfrm_unregister_type(&ipcomp6_type, AF_INET6); 204 return -EAGAIN; 205 } 206 return 0; 207 } 208 209 static void __exit ipcomp6_fini(void) 210 { 211 if (xfrm6_protocol_deregister(&ipcomp6_protocol, IPPROTO_COMP) < 0) 212 pr_info("%s: can't remove protocol\n", __func__); 213 xfrm_unregister_type(&ipcomp6_type, AF_INET6); 214 } 215 216 module_init(ipcomp6_init); 217 module_exit(ipcomp6_fini); 218 MODULE_LICENSE("GPL"); 219 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); 220 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); 221 222 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP); 223