net/ipv6/netfilter/ip6t_LOG.c

   1 /*
   2  * This is a module which is used for logging packets.
   3  */
   4
   5 /* (C) 2001 Jan Rekorajski <baggins@pld.org.pl>
   6  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.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 version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/if_arp.h>
  17 #include <linux/ip.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/icmpv6.h>
  20 #include <net/udp.h>
  21 #include <net/tcp.h>
  22 #include <net/ipv6.h>
  23 #include <linux/netfilter.h>
  24 #include <linux/netfilter/x_tables.h>
  25 #include <linux/netfilter_ipv6/ip6_tables.h>
  26
  27 MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
  28 MODULE_DESCRIPTION("IP6 tables LOG target module");
  29 MODULE_LICENSE("GPL");
  30
  31 struct in_device;
  32 #include <net/route.h>
  33 #include <linux/netfilter_ipv6/ip6t_LOG.h>
  34
  35 #if 0
  36 #define DEBUGP printk
  37 #else
  38 #define DEBUGP(format, args...)
  39 #endif
  40
  41 /* Use lock to serialize, so printks don't overlap */
  42 static DEFINE_SPINLOCK(log_lock);
  43
  44 /* One level of recursion won't kill us */
  45 static void dump_packet(const struct nf_loginfo *info,
  46                         const struct sk_buff *skb, unsigned int ip6hoff,
  47                         int recurse)
  48 {
  49         u_int8_t currenthdr;
  50         int fragment;
  51         struct ipv6hdr _ip6h, *ih;
  52         unsigned int ptr;
  53         unsigned int hdrlen = 0;
  54         unsigned int logflags;
  55
  56         if (info->type == NF_LOG_TYPE_LOG)
  57                 logflags = info->u.log.logflags;
  58         else
  59                 logflags = NF_LOG_MASK;
  60
  61         ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
  62         if (ih == NULL) {
  63                 printk("TRUNCATED");
  64                 return;
  65         }
  66
  67         /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
  68         printk("SRC=" NIP6_FMT " DST=" NIP6_FMT " ", NIP6(ih->saddr), NIP6(ih->daddr));
  69
  70         /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
  71         printk("LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
  72                ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
  73                (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
  74                ih->hop_limit,
  75                (ntohl(*(__be32 *)ih) & 0x000fffff));
  76
  77         fragment = 0;
  78         ptr = ip6hoff + sizeof(struct ipv6hdr);
  79         currenthdr = ih->nexthdr;
  80         while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
  81                 struct ipv6_opt_hdr _hdr, *hp;
  82
  83                 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
  84                 if (hp == NULL) {
  85                         printk("TRUNCATED");
  86                         return;
  87                 }
  88
  89                 /* Max length: 48 "OPT (...) " */
  90                 if (logflags & IP6T_LOG_IPOPT)
  91                         printk("OPT ( ");
  92
  93                 switch (currenthdr) {
  94                 case IPPROTO_FRAGMENT: {
  95                         struct frag_hdr _fhdr, *fh;
  96
  97                         printk("FRAG:");
  98                         fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
  99                                                 &_fhdr);
 100                         if (fh == NULL) {
 101                                 printk("TRUNCATED ");
 102                                 return;
 103                         }
 104
 105                         /* Max length: 6 "65535 " */
 106                         printk("%u ", ntohs(fh->frag_off) & 0xFFF8);
 107
 108                         /* Max length: 11 "INCOMPLETE " */
 109                         if (fh->frag_off & htons(0x0001))
 110                                 printk("INCOMPLETE ");
 111
 112                         printk("ID:%08x ", ntohl(fh->identification));
 113
 114                         if (ntohs(fh->frag_off) & 0xFFF8)
 115                                 fragment = 1;
 116
 117                         hdrlen = 8;
 118
 119                         break;
 120                 }
 121                 case IPPROTO_DSTOPTS:
 122                 case IPPROTO_ROUTING:
 123                 case IPPROTO_HOPOPTS:
 124                         if (fragment) {
 125                                 if (logflags & IP6T_LOG_IPOPT)
 126                                         printk(")");
 127                                 return;
 128                         }
 129                         hdrlen = ipv6_optlen(hp);
 130                         break;
 131                 /* Max Length */
 132                 case IPPROTO_AH:
 133                         if (logflags & IP6T_LOG_IPOPT) {
 134                                 struct ip_auth_hdr _ahdr, *ah;
 135
 136                                 /* Max length: 3 "AH " */
 137                                 printk("AH ");
 138
 139                                 if (fragment) {
 140                                         printk(")");
 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                                         printk("INCOMPLETE [%u bytes] )",
 152                                                skb->len - ptr);
 153                                         return;
 154                                 }
 155
 156                                 /* Length: 15 "SPI=0xF1234567 */
 157                                 printk("SPI=0x%x ", ntohl(ah->spi));
 158
 159                         }
 160
 161                         hdrlen = (hp->hdrlen+2)<<2;
 162                         break;
 163                 case IPPROTO_ESP:
 164                         if (logflags & IP6T_LOG_IPOPT) {
 165                                 struct ip_esp_hdr _esph, *eh;
 166
 167                                 /* Max length: 4 "ESP " */
 168                                 printk("ESP ");
 169
 170                                 if (fragment) {
 171                                         printk(")");
 172                                         return;
 173                                 }
 174
 175                                 /*
 176                                  * Max length: 26 "INCOMPLETE [65535 bytes] )"
 177                                  */
 178                                 eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 179                                                         &_esph);
 180                                 if (eh == NULL) {
 181                                         printk("INCOMPLETE [%u bytes] )",
 182                                                skb->len - ptr);
 183                                         return;
 184                                 }
 185
 186                                 /* Length: 16 "SPI=0xF1234567 )" */
 187                                 printk("SPI=0x%x )", ntohl(eh->spi) );
 188
 189                         }
 190                         return;
 191                 default:
 192                         /* Max length: 20 "Unknown Ext Hdr 255" */
 193                         printk("Unknown Ext Hdr %u", currenthdr);
 194                         return;
 195                 }
 196                 if (logflags & IP6T_LOG_IPOPT)
 197                         printk(") ");
 198
 199                 currenthdr = hp->nexthdr;
 200                 ptr += hdrlen;
 201         }
 202
 203         switch (currenthdr) {
 204         case IPPROTO_TCP: {
 205                 struct tcphdr _tcph, *th;
 206
 207                 /* Max length: 10 "PROTO=TCP " */
 208                 printk("PROTO=TCP ");
 209
 210                 if (fragment)
 211                         break;
 212
 213                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 214                 th = skb_header_pointer(skb, ptr, sizeof(_tcph), &_tcph);
 215                 if (th == NULL) {
 216                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 217                         return;
 218                 }
 219
 220                 /* Max length: 20 "SPT=65535 DPT=65535 " */
 221                 printk("SPT=%u DPT=%u ",
 222                        ntohs(th->source), ntohs(th->dest));
 223                 /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
 224                 if (logflags & IP6T_LOG_TCPSEQ)
 225                         printk("SEQ=%u ACK=%u ",
 226                                ntohl(th->seq), ntohl(th->ack_seq));
 227                 /* Max length: 13 "WINDOW=65535 " */
 228                 printk("WINDOW=%u ", ntohs(th->window));
 229                 /* Max length: 9 "RES=0x3C " */
 230                 printk("RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
 231                 /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
 232                 if (th->cwr)
 233                         printk("CWR ");
 234                 if (th->ece)
 235                         printk("ECE ");
 236                 if (th->urg)
 237                         printk("URG ");
 238                 if (th->ack)
 239                         printk("ACK ");
 240                 if (th->psh)
 241                         printk("PSH ");
 242                 if (th->rst)
 243                         printk("RST ");
 244                 if (th->syn)
 245                         printk("SYN ");
 246                 if (th->fin)
 247                         printk("FIN ");
 248                 /* Max length: 11 "URGP=65535 " */
 249                 printk("URGP=%u ", ntohs(th->urg_ptr));
 250
 251                 if ((logflags & IP6T_LOG_TCPOPT)
 252                     && th->doff * 4 > sizeof(struct tcphdr)) {
 253                         u_int8_t _opt[60 - sizeof(struct tcphdr)], *op;
 254                         unsigned int i;
 255                         unsigned int optsize = th->doff * 4
 256                                                - sizeof(struct tcphdr);
 257
 258                         op = skb_header_pointer(skb,
 259                                                 ptr + sizeof(struct tcphdr),
 260                                                 optsize, _opt);
 261                         if (op == NULL) {
 262                                 printk("OPT (TRUNCATED)");
 263                                 return;
 264                         }
 265
 266                         /* Max length: 127 "OPT (" 15*4*2chars ") " */
 267                         printk("OPT (");
 268                         for (i =0; i < optsize; i++)
 269                                 printk("%02X", op[i]);
 270                         printk(") ");
 271                 }
 272                 break;
 273         }
 274         case IPPROTO_UDP:
 275         case IPPROTO_UDPLITE: {
 276                 struct udphdr _udph, *uh;
 277
 278                 if (currenthdr == IPPROTO_UDP)
 279                         /* Max length: 10 "PROTO=UDP "     */
 280                         printk("PROTO=UDP " );
 281                 else    /* Max length: 14 "PROTO=UDPLITE " */
 282                         printk("PROTO=UDPLITE ");
 283
 284                 if (fragment)
 285                         break;
 286
 287                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 288                 uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
 289                 if (uh == NULL) {
 290                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 291                         return;
 292                 }
 293
 294                 /* Max length: 20 "SPT=65535 DPT=65535 " */
 295                 printk("SPT=%u DPT=%u LEN=%u ",
 296                        ntohs(uh->source), ntohs(uh->dest),
 297                        ntohs(uh->len));
 298                 break;
 299         }
 300         case IPPROTO_ICMPV6: {
 301                 struct icmp6hdr _icmp6h, *ic;
 302
 303                 /* Max length: 13 "PROTO=ICMPv6 " */
 304                 printk("PROTO=ICMPv6 ");
 305
 306                 if (fragment)
 307                         break;
 308
 309                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 310                 ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 311                 if (ic == NULL) {
 312                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 313                         return;
 314                 }
 315
 316                 /* Max length: 18 "TYPE=255 CODE=255 " */
 317                 printk("TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
 318
 319                 switch (ic->icmp6_type) {
 320                 case ICMPV6_ECHO_REQUEST:
 321                 case ICMPV6_ECHO_REPLY:
 322                         /* Max length: 19 "ID=65535 SEQ=65535 " */
 323                         printk("ID=%u SEQ=%u ",
 324                                 ntohs(ic->icmp6_identifier),
 325                                 ntohs(ic->icmp6_sequence));
 326                         break;
 327                 case ICMPV6_MGM_QUERY:
 328                 case ICMPV6_MGM_REPORT:
 329                 case ICMPV6_MGM_REDUCTION:
 330                         break;
 331
 332                 case ICMPV6_PARAMPROB:
 333                         /* Max length: 17 "POINTER=ffffffff " */
 334                         printk("POINTER=%08x ", ntohl(ic->icmp6_pointer));
 335                         /* Fall through */
 336                 case ICMPV6_DEST_UNREACH:
 337                 case ICMPV6_PKT_TOOBIG:
 338                 case ICMPV6_TIME_EXCEED:
 339                         /* Max length: 3+maxlen */
 340                         if (recurse) {
 341                                 printk("[");
 342                                 dump_packet(info, skb, ptr + sizeof(_icmp6h),
 343                                             0);
 344                                 printk("] ");
 345                         }
 346
 347                         /* Max length: 10 "MTU=65535 " */
 348                         if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
 349                                 printk("MTU=%u ", ntohl(ic->icmp6_mtu));
 350                 }
 351                 break;
 352         }
 353         /* Max length: 10 "PROTO=255 " */
 354         default:
 355                 printk("PROTO=%u ", currenthdr);
 356         }
 357
 358         /* Max length: 15 "UID=4294967295 " */
 359         if ((logflags & IP6T_LOG_UID) && recurse && skb->sk) {
 360                 read_lock_bh(&skb->sk->sk_callback_lock);
 361                 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
 362                         printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
 363                 read_unlock_bh(&skb->sk->sk_callback_lock);
 364         }
 365 }
 366
 367 static struct nf_loginfo default_loginfo = {
 368         .type   = NF_LOG_TYPE_LOG,
 369         .u = {
 370                 .log = {
 371                         .level    = 0,
 372                         .logflags = NF_LOG_MASK,
 373                 },
 374         },
 375 };
 376
 377 static void
 378 ip6t_log_packet(unsigned int pf,
 379                 unsigned int hooknum,
 380                 const struct sk_buff *skb,
 381                 const struct net_device *in,
 382                 const struct net_device *out,
 383                 const struct nf_loginfo *loginfo,
 384                 const char *prefix)
 385 {
 386         if (!loginfo)
 387                 loginfo = &default_loginfo;
 388
 389         spin_lock_bh(&log_lock);
 390         printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
 391                 prefix,
 392                 in ? in->name : "",
 393                 out ? out->name : "");
 394         if (in && !out) {
 395                 unsigned int len;
 396                 /* MAC logging for input chain only. */
 397                 printk("MAC=");
 398                 if (skb->dev && (len = skb->dev->hard_header_len) &&
 399                     skb->mac.raw != skb->nh.raw) {
 400                         unsigned char *p = skb->mac.raw;
 401                         int i;
 402
 403                         if (skb->dev->type == ARPHRD_SIT &&
 404                             (p -= ETH_HLEN) < skb->head)
 405                                 p = NULL;
 406
 407                         if (p != NULL) {
 408                                 for (i = 0; i < len; i++)
 409                                         printk("%02x%s", p[i],
 410                                                i == len - 1 ? "" : ":");
 411                         }
 412                         printk(" ");
 413
 414                         if (skb->dev->type == ARPHRD_SIT) {
 415                                 struct iphdr *iph = (struct iphdr *)skb->mac.raw;
 416                                 printk("TUNNEL=%u.%u.%u.%u->%u.%u.%u.%u ",
 417                                        NIPQUAD(iph->saddr),
 418                                        NIPQUAD(iph->daddr));
 419                         }
 420                 } else
 421                         printk(" ");
 422         }
 423
 424         dump_packet(loginfo, skb, (u8*)skb->nh.ipv6h - skb->data, 1);
 425         printk("\n");
 426         spin_unlock_bh(&log_lock);
 427 }
 428
 429 static unsigned int
 430 ip6t_log_target(struct sk_buff **pskb,
 431                 const struct net_device *in,
 432                 const struct net_device *out,
 433                 unsigned int hooknum,
 434                 const struct xt_target *target,
 435                 const void *targinfo)
 436 {
 437         const struct ip6t_log_info *loginfo = targinfo;
 438         struct nf_loginfo li;
 439
 440         li.type = NF_LOG_TYPE_LOG;
 441         li.u.log.level = loginfo->level;
 442         li.u.log.logflags = loginfo->logflags;
 443
 444         ip6t_log_packet(PF_INET6, hooknum, *pskb, in, out, &li,
 445                         loginfo->prefix);
 446         return XT_CONTINUE;
 447 }
 448
 449
 450 static int ip6t_log_checkentry(const char *tablename,
 451                                const void *entry,
 452                                const struct xt_target *target,
 453                                void *targinfo,
 454                                unsigned int hook_mask)
 455 {
 456         const struct ip6t_log_info *loginfo = targinfo;
 457
 458         if (loginfo->level >= 8) {
 459                 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
 460                 return 0;
 461         }
 462         if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
 463                 DEBUGP("LOG: prefix term %i\n",
 464                        loginfo->prefix[sizeof(loginfo->prefix)-1]);
 465                 return 0;
 466         }
 467         return 1;
 468 }
 469
 470 static struct xt_target ip6t_log_reg = {
 471         .name           = "LOG",
 472         .family         = AF_INET6,
 473         .target         = ip6t_log_target,
 474         .targetsize     = sizeof(struct ip6t_log_info),
 475         .checkentry     = ip6t_log_checkentry,
 476         .me             = THIS_MODULE,
 477 };
 478
 479 static struct nf_logger ip6t_logger = {
 480         .name           = "ip6t_LOG",
 481         .logfn          = &ip6t_log_packet,
 482         .me             = THIS_MODULE,
 483 };
 484
 485 static int __init ip6t_log_init(void)
 486 {
 487         int ret;
 488
 489         ret = xt_register_target(&ip6t_log_reg);
 490         if (ret < 0)
 491                 return ret;
 492         if (nf_log_register(PF_INET6, &ip6t_logger) < 0) {
 493                 printk(KERN_WARNING "ip6t_LOG: not logging via system console "
 494                        "since somebody else already registered for PF_INET6\n");
 495                 /* we cannot make module load fail here, since otherwise
 496                  * ip6tables userspace would abort */
 497         }
 498
 499         return 0;
 500 }
 501
 502 static void __exit ip6t_log_fini(void)
 503 {
 504         nf_log_unregister_logger(&ip6t_logger);
 505         xt_unregister_target(&ip6t_log_reg);
 506 }
 507
 508 module_init(ip6t_log_init);
 509 module_exit(ip6t_log_fini);