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_ipv6/ip6_tables.h>
  25
  26 MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
  27 MODULE_DESCRIPTION("IP6 tables LOG target module");
  28 MODULE_LICENSE("GPL");
  29
  30 struct in_device;
  31 #include <net/route.h>
  32 #include <linux/netfilter_ipv6/ip6t_LOG.h>
  33
  34 #if 0
  35 #define DEBUGP printk
  36 #else
  37 #define DEBUGP(format, args...)
  38 #endif
  39
  40 /* Use lock to serialize, so printks don't overlap */
  41 static DEFINE_SPINLOCK(log_lock);
  42
  43 /* One level of recursion won't kill us */
  44 static void dump_packet(const struct nf_loginfo *info,
  45                         const struct sk_buff *skb, unsigned int ip6hoff,
  46                         int recurse)
  47 {
  48         u_int8_t currenthdr;
  49         int fragment;
  50         struct ipv6hdr _ip6h, *ih;
  51         unsigned int ptr;
  52         unsigned int hdrlen = 0;
  53         unsigned int logflags;
  54
  55         if (info->type == NF_LOG_TYPE_LOG)
  56                 logflags = info->u.log.logflags;
  57         else
  58                 logflags = NF_LOG_MASK;
  59
  60         ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
  61         if (ih == NULL) {
  62                 printk("TRUNCATED");
  63                 return;
  64         }
  65
  66         /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000" */
  67         printk("SRC=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x ", NIP6(ih->saddr));
  68         printk("DST=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x ", 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(*(u_int32_t *)ih) & 0x0ff00000) >> 20,
  74                ih->hop_limit,
  75                (ntohl(*(u_int32_t *)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                 struct udphdr _udph, *uh;
 276
 277                 /* Max length: 10 "PROTO=UDP " */
 278                 printk("PROTO=UDP ");
 279
 280                 if (fragment)
 281                         break;
 282
 283                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 284                 uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
 285                 if (uh == NULL) {
 286                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 287                         return;
 288                 }
 289
 290                 /* Max length: 20 "SPT=65535 DPT=65535 " */
 291                 printk("SPT=%u DPT=%u LEN=%u ",
 292                        ntohs(uh->source), ntohs(uh->dest),
 293                        ntohs(uh->len));
 294                 break;
 295         }
 296         case IPPROTO_ICMPV6: {
 297                 struct icmp6hdr _icmp6h, *ic;
 298
 299                 /* Max length: 13 "PROTO=ICMPv6 " */
 300                 printk("PROTO=ICMPv6 ");
 301
 302                 if (fragment)
 303                         break;
 304
 305                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 306                 ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 307                 if (ic == NULL) {
 308                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 309                         return;
 310                 }
 311
 312                 /* Max length: 18 "TYPE=255 CODE=255 " */
 313                 printk("TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
 314
 315                 switch (ic->icmp6_type) {
 316                 case ICMPV6_ECHO_REQUEST:
 317                 case ICMPV6_ECHO_REPLY:
 318                         /* Max length: 19 "ID=65535 SEQ=65535 " */
 319                         printk("ID=%u SEQ=%u ",
 320                                 ntohs(ic->icmp6_identifier),
 321                                 ntohs(ic->icmp6_sequence));
 322                         break;
 323                 case ICMPV6_MGM_QUERY:
 324                 case ICMPV6_MGM_REPORT:
 325                 case ICMPV6_MGM_REDUCTION:
 326                         break;
 327
 328                 case ICMPV6_PARAMPROB:
 329                         /* Max length: 17 "POINTER=ffffffff " */
 330                         printk("POINTER=%08x ", ntohl(ic->icmp6_pointer));
 331                         /* Fall through */
 332                 case ICMPV6_DEST_UNREACH:
 333                 case ICMPV6_PKT_TOOBIG:
 334                 case ICMPV6_TIME_EXCEED:
 335                         /* Max length: 3+maxlen */
 336                         if (recurse) {
 337                                 printk("[");
 338                                 dump_packet(info, skb, ptr + sizeof(_icmp6h),
 339                                             0);
 340                                 printk("] ");
 341                         }
 342
 343                         /* Max length: 10 "MTU=65535 " */
 344                         if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
 345                                 printk("MTU=%u ", ntohl(ic->icmp6_mtu));
 346                 }
 347                 break;
 348         }
 349         /* Max length: 10 "PROTO=255 " */
 350         default:
 351                 printk("PROTO=%u ", currenthdr);
 352         }
 353
 354         /* Max length: 15 "UID=4294967295 " */
 355         if ((logflags & IP6T_LOG_UID) && recurse && skb->sk) {
 356                 read_lock_bh(&skb->sk->sk_callback_lock);
 357                 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
 358                         printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
 359                 read_unlock_bh(&skb->sk->sk_callback_lock);
 360         }
 361 }
 362
 363 static struct nf_loginfo default_loginfo = {
 364         .type   = NF_LOG_TYPE_LOG,
 365         .u = {
 366                 .log = {
 367                         .level    = 0,
 368                         .logflags = NF_LOG_MASK,
 369                 },
 370         },
 371 };
 372
 373 static void
 374 ip6t_log_packet(unsigned int pf,
 375                 unsigned int hooknum,
 376                 const struct sk_buff *skb,
 377                 const struct net_device *in,
 378                 const struct net_device *out,
 379                 const struct nf_loginfo *loginfo,
 380                 const char *prefix)
 381 {
 382         if (!loginfo)
 383                 loginfo = &default_loginfo;
 384
 385         spin_lock_bh(&log_lock);
 386         printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
 387                 prefix,
 388                 in ? in->name : "",
 389                 out ? out->name : "");
 390         if (in && !out) {
 391                 unsigned int len;
 392                 /* MAC logging for input chain only. */
 393                 printk("MAC=");
 394                 if (skb->dev && (len = skb->dev->hard_header_len) &&
 395                     skb->mac.raw != skb->nh.raw) {
 396                         unsigned char *p = skb->mac.raw;
 397                         int i;
 398
 399                         if (skb->dev->type == ARPHRD_SIT &&
 400                             (p -= ETH_HLEN) < skb->head)
 401                                 p = NULL;
 402
 403                         if (p != NULL) {
 404                                 for (i = 0; i < len; i++)
 405                                         printk("%02x%s", p[i],
 406                                                i == len - 1 ? "" : ":");
 407                         }
 408                         printk(" ");
 409
 410                         if (skb->dev->type == ARPHRD_SIT) {
 411                                 struct iphdr *iph = (struct iphdr *)skb->mac.raw;
 412                                 printk("TUNNEL=%u.%u.%u.%u->%u.%u.%u.%u ",
 413                                        NIPQUAD(iph->saddr),
 414                                        NIPQUAD(iph->daddr));
 415                         }
 416                 } else
 417                         printk(" ");
 418         }
 419
 420         dump_packet(loginfo, skb, (u8*)skb->nh.ipv6h - skb->data, 1);
 421         printk("\n");
 422         spin_unlock_bh(&log_lock);
 423 }
 424
 425 static unsigned int
 426 ip6t_log_target(struct sk_buff **pskb,
 427                 const struct net_device *in,
 428                 const struct net_device *out,
 429                 unsigned int hooknum,
 430                 const void *targinfo,
 431                 void *userinfo)
 432 {
 433         const struct ip6t_log_info *loginfo = targinfo;
 434         struct nf_loginfo li;
 435
 436         li.type = NF_LOG_TYPE_LOG;
 437         li.u.log.level = loginfo->level;
 438         li.u.log.logflags = loginfo->logflags;
 439
 440         nf_log_packet(PF_INET6, hooknum, *pskb, in, out, &li, loginfo->prefix);
 441
 442         return IP6T_CONTINUE;
 443 }
 444
 445
 446 static int ip6t_log_checkentry(const char *tablename,
 447                                const struct ip6t_entry *e,
 448                                void *targinfo,
 449                                unsigned int targinfosize,
 450                                unsigned int hook_mask)
 451 {
 452         const struct ip6t_log_info *loginfo = targinfo;
 453
 454         if (targinfosize != IP6T_ALIGN(sizeof(struct ip6t_log_info))) {
 455                 DEBUGP("LOG: targinfosize %u != %u\n",
 456                        targinfosize, IP6T_ALIGN(sizeof(struct ip6t_log_info)));
 457                 return 0;
 458         }
 459
 460         if (loginfo->level >= 8) {
 461                 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
 462                 return 0;
 463         }
 464
 465         if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
 466                 DEBUGP("LOG: prefix term %i\n",
 467                        loginfo->prefix[sizeof(loginfo->prefix)-1]);
 468                 return 0;
 469         }
 470
 471         return 1;
 472 }
 473
 474 static struct ip6t_target ip6t_log_reg = {
 475         .name           = "LOG",
 476         .target         = ip6t_log_target,
 477         .checkentry     = ip6t_log_checkentry,
 478         .me             = THIS_MODULE,
 479 };
 480
 481 static struct nf_logger ip6t_logger = {
 482         .name           = "ip6t_LOG",
 483         .logfn          = &ip6t_log_packet,
 484         .me             = THIS_MODULE,
 485 };
 486
 487 static int __init init(void)
 488 {
 489         if (ip6t_register_target(&ip6t_log_reg))
 490                 return -EINVAL;
 491         if (nf_log_register(PF_INET6, &ip6t_logger) < 0) {
 492                 printk(KERN_WARNING "ip6t_LOG: not logging via system console "
 493                        "since somebody else already registered for PF_INET6\n");
 494                 /* we cannot make module load fail here, since otherwise
 495                  * ip6tables userspace would abort */
 496         }
 497
 498         return 0;
 499 }
 500
 501 static void __exit fini(void)
 502 {
 503         nf_log_unregister_logger(&ip6t_logger);
 504         ip6t_unregister_target(&ip6t_log_reg);
 505 }
 506
 507 module_init(init);
 508 module_exit(fini);