linux/net/ipv6/netfilter/nf_log_ipv6.c
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   1/* (C) 1999-2001 Paul `Rusty' Russell
   2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   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
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/spinlock.h>
  14#include <linux/skbuff.h>
  15#include <linux/if_arp.h>
  16#include <linux/ip.h>
  17#include <net/ipv6.h>
  18#include <net/icmp.h>
  19#include <net/udp.h>
  20#include <net/tcp.h>
  21#include <net/route.h>
  22
  23#include <linux/netfilter.h>
  24#include <linux/netfilter_ipv6/ip6_tables.h>
  25#include <linux/netfilter/xt_LOG.h>
  26#include <net/netfilter/nf_log.h>
  27
  28static struct nf_loginfo default_loginfo = {
  29        .type   = NF_LOG_TYPE_LOG,
  30        .u = {
  31                .log = {
  32                        .level    = LOGLEVEL_NOTICE,
  33                        .logflags = NF_LOG_MASK,
  34                },
  35        },
  36};
  37
  38/* One level of recursion won't kill us */
  39static void dump_ipv6_packet(struct nf_log_buf *m,
  40                             const struct nf_loginfo *info,
  41                             const struct sk_buff *skb, unsigned int ip6hoff,
  42                             int recurse)
  43{
  44        u_int8_t currenthdr;
  45        int fragment;
  46        struct ipv6hdr _ip6h;
  47        const struct ipv6hdr *ih;
  48        unsigned int ptr;
  49        unsigned int hdrlen = 0;
  50        unsigned int logflags;
  51
  52        if (info->type == NF_LOG_TYPE_LOG)
  53                logflags = info->u.log.logflags;
  54        else
  55                logflags = NF_LOG_MASK;
  56
  57        ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
  58        if (ih == NULL) {
  59                nf_log_buf_add(m, "TRUNCATED");
  60                return;
  61        }
  62
  63        /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
  64        nf_log_buf_add(m, "SRC=%pI6 DST=%pI6 ", &ih->saddr, &ih->daddr);
  65
  66        /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
  67        nf_log_buf_add(m, "LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
  68               ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
  69               (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
  70               ih->hop_limit,
  71               (ntohl(*(__be32 *)ih) & 0x000fffff));
  72
  73        fragment = 0;
  74        ptr = ip6hoff + sizeof(struct ipv6hdr);
  75        currenthdr = ih->nexthdr;
  76        while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
  77                struct ipv6_opt_hdr _hdr;
  78                const struct ipv6_opt_hdr *hp;
  79
  80                hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
  81                if (hp == NULL) {
  82                        nf_log_buf_add(m, "TRUNCATED");
  83                        return;
  84                }
  85
  86                /* Max length: 48 "OPT (...) " */
  87                if (logflags & XT_LOG_IPOPT)
  88                        nf_log_buf_add(m, "OPT ( ");
  89
  90                switch (currenthdr) {
  91                case IPPROTO_FRAGMENT: {
  92                        struct frag_hdr _fhdr;
  93                        const struct frag_hdr *fh;
  94
  95                        nf_log_buf_add(m, "FRAG:");
  96                        fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
  97                                                &_fhdr);
  98                        if (fh == NULL) {
  99                                nf_log_buf_add(m, "TRUNCATED ");
 100                                return;
 101                        }
 102
 103                        /* Max length: 6 "65535 " */
 104                        nf_log_buf_add(m, "%u ", ntohs(fh->frag_off) & 0xFFF8);
 105
 106                        /* Max length: 11 "INCOMPLETE " */
 107                        if (fh->frag_off & htons(0x0001))
 108                                nf_log_buf_add(m, "INCOMPLETE ");
 109
 110                        nf_log_buf_add(m, "ID:%08x ",
 111                                       ntohl(fh->identification));
 112
 113                        if (ntohs(fh->frag_off) & 0xFFF8)
 114                                fragment = 1;
 115
 116                        hdrlen = 8;
 117
 118                        break;
 119                }
 120                case IPPROTO_DSTOPTS:
 121                case IPPROTO_ROUTING:
 122                case IPPROTO_HOPOPTS:
 123                        if (fragment) {
 124                                if (logflags & XT_LOG_IPOPT)
 125                                        nf_log_buf_add(m, ")");
 126                                return;
 127                        }
 128                        hdrlen = ipv6_optlen(hp);
 129                        break;
 130                /* Max Length */
 131                case IPPROTO_AH:
 132                        if (logflags & XT_LOG_IPOPT) {
 133                                struct ip_auth_hdr _ahdr;
 134                                const struct ip_auth_hdr *ah;
 135
 136                                /* Max length: 3 "AH " */
 137                                nf_log_buf_add(m, "AH ");
 138
 139                                if (fragment) {
 140                                        nf_log_buf_add(m, ")");
 141                                        return;
 142                                }
 143
 144                                ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
 145                                                        &_ahdr);
 146                                if (ah == NULL) {
 147                                        /*
 148                                         * Max length: 26 "INCOMPLETE [65535
 149                                         *  bytes] )"
 150                                         */
 151                                        nf_log_buf_add(m, "INCOMPLETE [%u bytes] )",
 152                                                       skb->len - ptr);
 153                                        return;
 154                                }
 155
 156                                /* Length: 15 "SPI=0xF1234567 */
 157                                nf_log_buf_add(m, "SPI=0x%x ", ntohl(ah->spi));
 158
 159                        }
 160
 161                        hdrlen = (hp->hdrlen+2)<<2;
 162                        break;
 163                case IPPROTO_ESP:
 164                        if (logflags & XT_LOG_IPOPT) {
 165                                struct ip_esp_hdr _esph;
 166                                const struct ip_esp_hdr *eh;
 167
 168                                /* Max length: 4 "ESP " */
 169                                nf_log_buf_add(m, "ESP ");
 170
 171                                if (fragment) {
 172                                        nf_log_buf_add(m, ")");
 173                                        return;
 174                                }
 175
 176                                /*
 177                                 * Max length: 26 "INCOMPLETE [65535 bytes] )"
 178                                 */
 179                                eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 180                                                        &_esph);
 181                                if (eh == NULL) {
 182                                        nf_log_buf_add(m, "INCOMPLETE [%u bytes] )",
 183                                                       skb->len - ptr);
 184                                        return;
 185                                }
 186
 187                                /* Length: 16 "SPI=0xF1234567 )" */
 188                                nf_log_buf_add(m, "SPI=0x%x )",
 189                                               ntohl(eh->spi));
 190                        }
 191                        return;
 192                default:
 193                        /* Max length: 20 "Unknown Ext Hdr 255" */
 194                        nf_log_buf_add(m, "Unknown Ext Hdr %u", currenthdr);
 195                        return;
 196                }
 197                if (logflags & XT_LOG_IPOPT)
 198                        nf_log_buf_add(m, ") ");
 199
 200                currenthdr = hp->nexthdr;
 201                ptr += hdrlen;
 202        }
 203
 204        switch (currenthdr) {
 205        case IPPROTO_TCP:
 206                if (nf_log_dump_tcp_header(m, skb, currenthdr, fragment,
 207                                           ptr, logflags))
 208                        return;
 209                break;
 210        case IPPROTO_UDP:
 211        case IPPROTO_UDPLITE:
 212                if (nf_log_dump_udp_header(m, skb, currenthdr, fragment, ptr))
 213                        return;
 214                break;
 215        case IPPROTO_ICMPV6: {
 216                struct icmp6hdr _icmp6h;
 217                const struct icmp6hdr *ic;
 218
 219                /* Max length: 13 "PROTO=ICMPv6 " */
 220                nf_log_buf_add(m, "PROTO=ICMPv6 ");
 221
 222                if (fragment)
 223                        break;
 224
 225                /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 226                ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 227                if (ic == NULL) {
 228                        nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
 229                                       skb->len - ptr);
 230                        return;
 231                }
 232
 233                /* Max length: 18 "TYPE=255 CODE=255 " */
 234                nf_log_buf_add(m, "TYPE=%u CODE=%u ",
 235                               ic->icmp6_type, ic->icmp6_code);
 236
 237                switch (ic->icmp6_type) {
 238                case ICMPV6_ECHO_REQUEST:
 239                case ICMPV6_ECHO_REPLY:
 240                        /* Max length: 19 "ID=65535 SEQ=65535 " */
 241                        nf_log_buf_add(m, "ID=%u SEQ=%u ",
 242                                ntohs(ic->icmp6_identifier),
 243                                ntohs(ic->icmp6_sequence));
 244                        break;
 245                case ICMPV6_MGM_QUERY:
 246                case ICMPV6_MGM_REPORT:
 247                case ICMPV6_MGM_REDUCTION:
 248                        break;
 249
 250                case ICMPV6_PARAMPROB:
 251                        /* Max length: 17 "POINTER=ffffffff " */
 252                        nf_log_buf_add(m, "POINTER=%08x ",
 253                                       ntohl(ic->icmp6_pointer));
 254                        /* Fall through */
 255                case ICMPV6_DEST_UNREACH:
 256                case ICMPV6_PKT_TOOBIG:
 257                case ICMPV6_TIME_EXCEED:
 258                        /* Max length: 3+maxlen */
 259                        if (recurse) {
 260                                nf_log_buf_add(m, "[");
 261                                dump_ipv6_packet(m, info, skb,
 262                                                 ptr + sizeof(_icmp6h), 0);
 263                                nf_log_buf_add(m, "] ");
 264                        }
 265
 266                        /* Max length: 10 "MTU=65535 " */
 267                        if (ic->icmp6_type == ICMPV6_PKT_TOOBIG) {
 268                                nf_log_buf_add(m, "MTU=%u ",
 269                                               ntohl(ic->icmp6_mtu));
 270                        }
 271                }
 272                break;
 273        }
 274        /* Max length: 10 "PROTO=255 " */
 275        default:
 276                nf_log_buf_add(m, "PROTO=%u ", currenthdr);
 277        }
 278
 279        /* Max length: 15 "UID=4294967295 " */
 280        if ((logflags & XT_LOG_UID) && recurse)
 281                nf_log_dump_sk_uid_gid(m, skb->sk);
 282
 283        /* Max length: 16 "MARK=0xFFFFFFFF " */
 284        if (recurse && skb->mark)
 285                nf_log_buf_add(m, "MARK=0x%x ", skb->mark);
 286}
 287
 288static void dump_ipv6_mac_header(struct nf_log_buf *m,
 289                                 const struct nf_loginfo *info,
 290                                 const struct sk_buff *skb)
 291{
 292        struct net_device *dev = skb->dev;
 293        unsigned int logflags = 0;
 294
 295        if (info->type == NF_LOG_TYPE_LOG)
 296                logflags = info->u.log.logflags;
 297
 298        if (!(logflags & XT_LOG_MACDECODE))
 299                goto fallback;
 300
 301        switch (dev->type) {
 302        case ARPHRD_ETHER:
 303                nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
 304                       eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
 305                       ntohs(eth_hdr(skb)->h_proto));
 306                return;
 307        default:
 308                break;
 309        }
 310
 311fallback:
 312        nf_log_buf_add(m, "MAC=");
 313        if (dev->hard_header_len &&
 314            skb->mac_header != skb->network_header) {
 315                const unsigned char *p = skb_mac_header(skb);
 316                unsigned int len = dev->hard_header_len;
 317                unsigned int i;
 318
 319                if (dev->type == ARPHRD_SIT) {
 320                        p -= ETH_HLEN;
 321
 322                        if (p < skb->head)
 323                                p = NULL;
 324                }
 325
 326                if (p != NULL) {
 327                        nf_log_buf_add(m, "%02x", *p++);
 328                        for (i = 1; i < len; i++)
 329                                nf_log_buf_add(m, ":%02x", *p++);
 330                }
 331                nf_log_buf_add(m, " ");
 332
 333                if (dev->type == ARPHRD_SIT) {
 334                        const struct iphdr *iph =
 335                                (struct iphdr *)skb_mac_header(skb);
 336                        nf_log_buf_add(m, "TUNNEL=%pI4->%pI4 ", &iph->saddr,
 337                                       &iph->daddr);
 338                }
 339        } else {
 340                nf_log_buf_add(m, " ");
 341        }
 342}
 343
 344static void nf_log_ip6_packet(struct net *net, u_int8_t pf,
 345                              unsigned int hooknum, const struct sk_buff *skb,
 346                              const struct net_device *in,
 347                              const struct net_device *out,
 348                              const struct nf_loginfo *loginfo,
 349                              const char *prefix)
 350{
 351        struct nf_log_buf *m;
 352
 353        /* FIXME: Disabled from containers until syslog ns is supported */
 354        if (!net_eq(net, &init_net))
 355                return;
 356
 357        m = nf_log_buf_open();
 358
 359        if (!loginfo)
 360                loginfo = &default_loginfo;
 361
 362        nf_log_dump_packet_common(m, pf, hooknum, skb, in, out,
 363                                  loginfo, prefix);
 364
 365        if (in != NULL)
 366                dump_ipv6_mac_header(m, loginfo, skb);
 367
 368        dump_ipv6_packet(m, loginfo, skb, skb_network_offset(skb), 1);
 369
 370        nf_log_buf_close(m);
 371}
 372
 373static struct nf_logger nf_ip6_logger __read_mostly = {
 374        .name           = "nf_log_ipv6",
 375        .type           = NF_LOG_TYPE_LOG,
 376        .logfn          = nf_log_ip6_packet,
 377        .me             = THIS_MODULE,
 378};
 379
 380static int __net_init nf_log_ipv6_net_init(struct net *net)
 381{
 382        nf_log_set(net, NFPROTO_IPV6, &nf_ip6_logger);
 383        return 0;
 384}
 385
 386static void __net_exit nf_log_ipv6_net_exit(struct net *net)
 387{
 388        nf_log_unset(net, &nf_ip6_logger);
 389}
 390
 391static struct pernet_operations nf_log_ipv6_net_ops = {
 392        .init = nf_log_ipv6_net_init,
 393        .exit = nf_log_ipv6_net_exit,
 394};
 395
 396static int __init nf_log_ipv6_init(void)
 397{
 398        int ret;
 399
 400        ret = register_pernet_subsys(&nf_log_ipv6_net_ops);
 401        if (ret < 0)
 402                return ret;
 403
 404        ret = nf_log_register(NFPROTO_IPV6, &nf_ip6_logger);
 405        if (ret < 0) {
 406                pr_err("failed to register logger\n");
 407                goto err1;
 408        }
 409
 410        return 0;
 411
 412err1:
 413        unregister_pernet_subsys(&nf_log_ipv6_net_ops);
 414        return ret;
 415}
 416
 417static void __exit nf_log_ipv6_exit(void)
 418{
 419        unregister_pernet_subsys(&nf_log_ipv6_net_ops);
 420        nf_log_unregister(&nf_ip6_logger);
 421}
 422
 423module_init(nf_log_ipv6_init);
 424module_exit(nf_log_ipv6_exit);
 425
 426MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
 427MODULE_DESCRIPTION("Netfilter IPv6 packet logging");
 428MODULE_LICENSE("GPL");
 429MODULE_ALIAS_NF_LOGGER(AF_INET6, 0);
 430