1/* 2 * Copyright (C)2003,2004 USAGI/WIDE Project 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * Author: 9 * Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp> 10 */ 11 12#include <linux/types.h> 13#include <linux/timer.h> 14#include <linux/module.h> 15#include <linux/netfilter.h> 16#include <linux/in6.h> 17#include <linux/icmpv6.h> 18#include <linux/ipv6.h> 19#include <net/ipv6.h> 20#include <net/ip6_checksum.h> 21#include <linux/seq_file.h> 22#include <linux/netfilter_ipv6.h> 23#include <net/netfilter/nf_conntrack_tuple.h> 24#include <net/netfilter/nf_conntrack_l4proto.h> 25#include <net/netfilter/nf_conntrack_core.h> 26#include <net/netfilter/nf_conntrack_zones.h> 27#include <net/netfilter/ipv6/nf_conntrack_icmpv6.h> 28#include <net/netfilter/nf_log.h> 29 30static unsigned int nf_ct_icmpv6_timeout __read_mostly = 30*HZ; 31 32static bool icmpv6_pkt_to_tuple(const struct sk_buff *skb, 33 unsigned int dataoff, 34 struct nf_conntrack_tuple *tuple) 35{ 36 const struct icmp6hdr *hp; 37 struct icmp6hdr _hdr; 38 39 hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); 40 if (hp == NULL) 41 return false; 42 tuple->dst.u.icmp.type = hp->icmp6_type; 43 tuple->src.u.icmp.id = hp->icmp6_identifier; 44 tuple->dst.u.icmp.code = hp->icmp6_code; 45 46 return true; 47} 48 49/* Add 1; spaces filled with 0. */ 50static const u_int8_t invmap[] = { 51 [ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1, 52 [ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1, 53 [ICMPV6_NI_QUERY - 128] = ICMPV6_NI_REPLY + 1, 54 [ICMPV6_NI_REPLY - 128] = ICMPV6_NI_QUERY +1 55}; 56 57static const u_int8_t noct_valid_new[] = { 58 [ICMPV6_MGM_QUERY - 130] = 1, 59 [ICMPV6_MGM_REPORT -130] = 1, 60 [ICMPV6_MGM_REDUCTION - 130] = 1, 61 [NDISC_ROUTER_SOLICITATION - 130] = 1, 62 [NDISC_ROUTER_ADVERTISEMENT - 130] = 1, 63 [NDISC_NEIGHBOUR_SOLICITATION - 130] = 1, 64 [NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1, 65 [ICMPV6_MLD2_REPORT - 130] = 1 66}; 67 68static bool icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple, 69 const struct nf_conntrack_tuple *orig) 70{ 71 int type = orig->dst.u.icmp.type - 128; 72 if (type < 0 || type >= sizeof(invmap) || !invmap[type]) 73 return false; 74 75 tuple->src.u.icmp.id = orig->src.u.icmp.id; 76 tuple->dst.u.icmp.type = invmap[type] - 1; 77 tuple->dst.u.icmp.code = orig->dst.u.icmp.code; 78 return true; 79} 80 81/* Print out the per-protocol part of the tuple. */ 82static int icmpv6_print_tuple(struct seq_file *s, 83 const struct nf_conntrack_tuple *tuple) 84{ 85 return seq_printf(s, "type=%u code=%u id=%u ", 86 tuple->dst.u.icmp.type, 87 tuple->dst.u.icmp.code, 88 ntohs(tuple->src.u.icmp.id)); 89} 90 91/* Returns verdict for packet, or -1 for invalid. */ 92static int icmpv6_packet(struct nf_conn *ct, 93 const struct sk_buff *skb, 94 unsigned int dataoff, 95 enum ip_conntrack_info ctinfo, 96 u_int8_t pf, 97 unsigned int hooknum) 98{ 99 /* Do not immediately delete the connection after the first 100 successful reply to avoid excessive conntrackd traffic 101 and also to handle correctly ICMP echo reply duplicates. */ 102 nf_ct_refresh_acct(ct, ctinfo, skb, nf_ct_icmpv6_timeout); 103 104 return NF_ACCEPT; 105} 106 107/* Called when a new connection for this protocol found. */ 108static bool icmpv6_new(struct nf_conn *ct, const struct sk_buff *skb, 109 unsigned int dataoff) 110{ 111 static const u_int8_t valid_new[] = { 112 [ICMPV6_ECHO_REQUEST - 128] = 1, 113 [ICMPV6_NI_QUERY - 128] = 1 114 }; 115 int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128; 116 117 if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) { 118 /* Can't create a new ICMPv6 `conn' with this. */ 119 pr_debug("icmpv6: can't create new conn with type %u\n", 120 type + 128); 121 nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple); 122 if (LOG_INVALID(nf_ct_net(ct), IPPROTO_ICMPV6)) 123 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL, 124 "nf_ct_icmpv6: invalid new with type %d ", 125 type + 128); 126 return false; 127 } 128 return true; 129} 130 131static int 132icmpv6_error_message(struct net *net, struct nf_conn *tmpl, 133 struct sk_buff *skb, 134 unsigned int icmp6off, 135 enum ip_conntrack_info *ctinfo, 136 unsigned int hooknum) 137{ 138 struct nf_conntrack_tuple intuple, origtuple; 139 const struct nf_conntrack_tuple_hash *h; 140 const struct nf_conntrack_l4proto *inproto; 141 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 142 143 NF_CT_ASSERT(skb->nfct == NULL); 144 145 /* Are they talking about one of our connections? */ 146 if (!nf_ct_get_tuplepr(skb, 147 skb_network_offset(skb) 148 + sizeof(struct ipv6hdr) 149 + sizeof(struct icmp6hdr), 150 PF_INET6, &origtuple)) { 151 pr_debug("icmpv6_error: Can't get tuple\n"); 152 return -NF_ACCEPT; 153 } 154 155 /* rcu_read_lock()ed by nf_hook_slow */ 156 inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum); 157 158 /* Ordinarily, we'd expect the inverted tupleproto, but it's 159 been preserved inside the ICMP. */ 160 if (!nf_ct_invert_tuple(&intuple, &origtuple, 161 &nf_conntrack_l3proto_ipv6, inproto)) { 162 pr_debug("icmpv6_error: Can't invert tuple\n"); 163 return -NF_ACCEPT; 164 } 165 166 *ctinfo = IP_CT_RELATED; 167 168 h = nf_conntrack_find_get(net, zone, &intuple); 169 if (!h) { 170 pr_debug("icmpv6_error: no match\n"); 171 return -NF_ACCEPT; 172 } else { 173 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) 174 *ctinfo += IP_CT_IS_REPLY; 175 } 176 177 /* Update skb to refer to this connection */ 178 skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general; 179 skb->nfctinfo = *ctinfo; 180 return -NF_ACCEPT; 181} 182 183static int 184icmpv6_error(struct net *net, struct nf_conn *tmpl, 185 struct sk_buff *skb, unsigned int dataoff, 186 enum ip_conntrack_info *ctinfo, u_int8_t pf, unsigned int hooknum) 187{ 188 const struct icmp6hdr *icmp6h; 189 struct icmp6hdr _ih; 190 int type; 191 192 icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih); 193 if (icmp6h == NULL) { 194 if (LOG_INVALID(net, IPPROTO_ICMPV6)) 195 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL, 196 "nf_ct_icmpv6: short packet "); 197 return -NF_ACCEPT; 198 } 199 200 if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING && 201 nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) { 202 if (LOG_INVALID(net, IPPROTO_ICMPV6)) 203 nf_log_packet(PF_INET6, 0, skb, NULL, NULL, NULL, 204 "nf_ct_icmpv6: ICMPv6 checksum failed "); 205 return -NF_ACCEPT; 206 } 207 208 type = icmp6h->icmp6_type - 130; 209 if (type >= 0 && type < sizeof(noct_valid_new) && 210 noct_valid_new[type]) { 211 skb->nfct = &nf_ct_untracked_get()->ct_general; 212 skb->nfctinfo = IP_CT_NEW; 213 nf_conntrack_get(skb->nfct); 214 return NF_ACCEPT; 215 } 216 217 /* is not error message ? */ 218 if (icmp6h->icmp6_type >= 128) 219 return NF_ACCEPT; 220 221 return icmpv6_error_message(net, tmpl, skb, dataoff, ctinfo, hooknum); 222} 223 224#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) 225 226#include <linux/netfilter/nfnetlink.h> 227#include <linux/netfilter/nfnetlink_conntrack.h> 228static int icmpv6_tuple_to_nlattr(struct sk_buff *skb, 229 const struct nf_conntrack_tuple *t) 230{ 231 NLA_PUT_BE16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id); 232 NLA_PUT_U8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type); 233 NLA_PUT_U8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code); 234 235 return 0; 236 237nla_put_failure: 238 return -1; 239} 240 241static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = { 242 [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 }, 243 [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 }, 244 [CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 }, 245}; 246 247static int icmpv6_nlattr_to_tuple(struct nlattr *tb[], 248 struct nf_conntrack_tuple *tuple) 249{ 250 if (!tb[CTA_PROTO_ICMPV6_TYPE] || 251 !tb[CTA_PROTO_ICMPV6_CODE] || 252 !tb[CTA_PROTO_ICMPV6_ID]) 253 return -EINVAL; 254 255 tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]); 256 tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]); 257 tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]); 258 259 if (tuple->dst.u.icmp.type < 128 || 260 tuple->dst.u.icmp.type - 128 >= sizeof(invmap) || 261 !invmap[tuple->dst.u.icmp.type - 128]) 262 return -EINVAL; 263 264 return 0; 265} 266 267static int icmpv6_nlattr_tuple_size(void) 268{ 269 return nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1); 270} 271#endif 272 273#ifdef CONFIG_SYSCTL 274static struct ctl_table_header *icmpv6_sysctl_header; 275static struct ctl_table icmpv6_sysctl_table[] = { 276 { 277 .procname = "nf_conntrack_icmpv6_timeout", 278 .data = &nf_ct_icmpv6_timeout, 279 .maxlen = sizeof(unsigned int), 280 .mode = 0644, 281 .proc_handler = proc_dointvec_jiffies, 282 }, 283 { } 284}; 285#endif /* CONFIG_SYSCTL */ 286 287struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 __read_mostly = 288{ 289 .l3proto = PF_INET6, 290 .l4proto = IPPROTO_ICMPV6, 291 .name = "icmpv6", 292 .pkt_to_tuple = icmpv6_pkt_to_tuple, 293 .invert_tuple = icmpv6_invert_tuple, 294 .print_tuple = icmpv6_print_tuple, 295 .packet = icmpv6_packet, 296 .new = icmpv6_new, 297 .error = icmpv6_error, 298#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) 299 .tuple_to_nlattr = icmpv6_tuple_to_nlattr, 300 .nlattr_tuple_size = icmpv6_nlattr_tuple_size, 301 .nlattr_to_tuple = icmpv6_nlattr_to_tuple, 302 .nla_policy = icmpv6_nla_policy, 303#endif 304#ifdef CONFIG_SYSCTL 305 .ctl_table_header = &icmpv6_sysctl_header, 306 .ctl_table = icmpv6_sysctl_table, 307#endif 308}; 309