SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/netfilter/nfnetlink_log.c

   1 /*
   2  * This is a module which is used for logging packets to userspace via
   3  * nfetlink.
   4  *
   5  * (C) 2005 by Harald Welte <laforge@netfilter.org>
   6  *
   7  * Based on the old ipv4-only ipt_ULOG.c:
   8  * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14 #include <linux/module.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/init.h>
  17 #include <linux/ip.h>
  18 #include <linux/ipv6.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/netfilter.h>
  21 #include <linux/netlink.h>
  22 #include <linux/netfilter/nfnetlink.h>
  23 #include <linux/netfilter/nfnetlink_log.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/sysctl.h>
  26 #include <linux/proc_fs.h>
  27 #include <linux/security.h>
  28 #include <linux/list.h>
  29 #include <linux/jhash.h>
  30 #include <linux/random.h>
  31 #include <net/sock.h>
  32
  33 #include <asm/atomic.h>
  34
  35 #ifdef CONFIG_BRIDGE_NETFILTER
  36 #include "../bridge/br_private.h"
  37 #endif
  38
  39 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  40 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  41 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  42
  43 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
  44                                      printk(x, ## args); } while (0);
  45
  46 #if 0
  47 #define UDEBUG(x, args ...)     printk(KERN_DEBUG "%s(%d):%s(): " x,       \
  48                                         __FILE__, __LINE__, __FUNCTION__,  \
  49                                         ## args)
  50 #else
  51 #define UDEBUG(x, ...)
  52 #endif
  53
  54 struct nfulnl_instance {
  55         struct hlist_node hlist;        /* global list of instances */
  56         spinlock_t lock;
  57         atomic_t use;                   /* use count */
  58
  59         unsigned int qlen;              /* number of nlmsgs in skb */
  60         struct sk_buff *skb;            /* pre-allocatd skb */
  61         struct nlmsghdr *lastnlh;       /* netlink header of last msg in skb */
  62         struct timer_list timer;
  63         int peer_pid;                   /* PID of the peer process */
  64
  65         /* configurable parameters */
  66         unsigned int flushtimeout;      /* timeout until queue flush */
  67         unsigned int nlbufsiz;          /* netlink buffer allocation size */
  68         unsigned int qthreshold;        /* threshold of the queue */
  69         u_int32_t copy_range;
  70         u_int32_t seq;                  /* instance-local sequential counter */
  71         u_int16_t group_num;            /* number of this queue */
  72         u_int16_t flags;
  73         u_int8_t copy_mode;
  74 };
  75
  76 static DEFINE_RWLOCK(instances_lock);
  77 static atomic_t global_seq;
  78
  79 #define INSTANCE_BUCKETS        16
  80 static struct hlist_head instance_table[INSTANCE_BUCKETS];
  81 static unsigned int hash_init;
  82
  83 static inline u_int8_t instance_hashfn(u_int16_t group_num)
  84 {
  85         return ((group_num & 0xff) % INSTANCE_BUCKETS);
  86 }
  87
  88 static struct nfulnl_instance *
  89 __instance_lookup(u_int16_t group_num)
  90 {
  91         struct hlist_head *head;
  92         struct hlist_node *pos;
  93         struct nfulnl_instance *inst;
  94
  95         UDEBUG("entering (group_num=%u)\n", group_num);
  96
  97         head = &instance_table[instance_hashfn(group_num)];
  98         hlist_for_each_entry(inst, pos, head, hlist) {
  99                 if (inst->group_num == group_num)
 100                         return inst;
 101         }
 102         return NULL;
 103 }
 104
 105 static inline void
 106 instance_get(struct nfulnl_instance *inst)
 107 {
 108         atomic_inc(&inst->use);
 109 }
 110
 111 static struct nfulnl_instance *
 112 instance_lookup_get(u_int16_t group_num)
 113 {
 114         struct nfulnl_instance *inst;
 115
 116         read_lock_bh(&instances_lock);
 117         inst = __instance_lookup(group_num);
 118         if (inst)
 119                 instance_get(inst);
 120         read_unlock_bh(&instances_lock);
 121
 122         return inst;
 123 }
 124
 125 static void
 126 instance_put(struct nfulnl_instance *inst)
 127 {
 128         if (inst && atomic_dec_and_test(&inst->use)) {
 129                 UDEBUG("kfree(inst=%p)\n", inst);
 130                 kfree(inst);
 131                 module_put(THIS_MODULE);
 132         }
 133 }
 134
 135 static void nfulnl_timer(unsigned long data);
 136
 137 static struct nfulnl_instance *
 138 instance_create(u_int16_t group_num, int pid)
 139 {
 140         struct nfulnl_instance *inst;
 141
 142         UDEBUG("entering (group_num=%u, pid=%d)\n", group_num,
 143                 pid);
 144
 145         write_lock_bh(&instances_lock);
 146         if (__instance_lookup(group_num)) {
 147                 inst = NULL;
 148                 UDEBUG("aborting, instance already exists\n");
 149                 goto out_unlock;
 150         }
 151
 152         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 153         if (!inst)
 154                 goto out_unlock;
 155
 156         INIT_HLIST_NODE(&inst->hlist);
 157         spin_lock_init(&inst->lock);
 158         /* needs to be two, since we _put() after creation */
 159         atomic_set(&inst->use, 2);
 160
 161         init_timer(&inst->timer);
 162         inst->timer.function = nfulnl_timer;
 163         inst->timer.data = (unsigned long)inst;
 164         /* don't start timer yet. (re)start it  with every packet */
 165
 166         inst->peer_pid = pid;
 167         inst->group_num = group_num;
 168
 169         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 170         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 171         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 172         inst->copy_mode         = NFULNL_COPY_PACKET;
 173         inst->copy_range        = 0xffff;
 174
 175         if (!try_module_get(THIS_MODULE))
 176                 goto out_free;
 177
 178         hlist_add_head(&inst->hlist,
 179                        &instance_table[instance_hashfn(group_num)]);
 180
 181         UDEBUG("newly added node: %p, next=%p\n", &inst->hlist,
 182                 inst->hlist.next);
 183
 184         write_unlock_bh(&instances_lock);
 185
 186         return inst;
 187
 188 out_free:
 189         instance_put(inst);
 190 out_unlock:
 191         write_unlock_bh(&instances_lock);
 192         return NULL;
 193 }
 194
 195 static int __nfulnl_send(struct nfulnl_instance *inst);
 196
 197 static void
 198 __instance_destroy(struct nfulnl_instance *inst)
 199 {
 200         /* first pull it out of the global list */
 201         UDEBUG("removing instance %p (queuenum=%u) from hash\n",
 202                 inst, inst->group_num);
 203
 204         hlist_del(&inst->hlist);
 205
 206         /* then flush all pending packets from skb */
 207
 208         spin_lock_bh(&inst->lock);
 209         if (inst->skb) {
 210                 /* timer "holds" one reference (we have one more) */
 211                 if (del_timer(&inst->timer))
 212                         instance_put(inst);
 213                 if (inst->qlen)
 214                         __nfulnl_send(inst);
 215                 if (inst->skb) {
 216                         kfree_skb(inst->skb);
 217                         inst->skb = NULL;
 218                 }
 219         }
 220         spin_unlock_bh(&inst->lock);
 221
 222         /* and finally put the refcount */
 223         instance_put(inst);
 224 }
 225
 226 static inline void
 227 instance_destroy(struct nfulnl_instance *inst)
 228 {
 229         write_lock_bh(&instances_lock);
 230         __instance_destroy(inst);
 231         write_unlock_bh(&instances_lock);
 232 }
 233
 234 static int
 235 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 236                   unsigned int range)
 237 {
 238         int status = 0;
 239
 240         spin_lock_bh(&inst->lock);
 241
 242         switch (mode) {
 243         case NFULNL_COPY_NONE:
 244         case NFULNL_COPY_META:
 245                 inst->copy_mode = mode;
 246                 inst->copy_range = 0;
 247                 break;
 248
 249         case NFULNL_COPY_PACKET:
 250                 inst->copy_mode = mode;
 251                 /* we're using struct nfattr which has 16bit nfa_len */
 252                 if (range > 0xffff)
 253                         inst->copy_range = 0xffff;
 254                 else
 255                         inst->copy_range = range;
 256                 break;
 257
 258         default:
 259                 status = -EINVAL;
 260                 break;
 261         }
 262
 263         spin_unlock_bh(&inst->lock);
 264
 265         return status;
 266 }
 267
 268 static int
 269 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 270 {
 271         int status;
 272
 273         spin_lock_bh(&inst->lock);
 274         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 275                 status = -ERANGE;
 276         else if (nlbufsiz > 131072)
 277                 status = -ERANGE;
 278         else {
 279                 inst->nlbufsiz = nlbufsiz;
 280                 status = 0;
 281         }
 282         spin_unlock_bh(&inst->lock);
 283
 284         return status;
 285 }
 286
 287 static int
 288 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 289 {
 290         spin_lock_bh(&inst->lock);
 291         inst->flushtimeout = timeout;
 292         spin_unlock_bh(&inst->lock);
 293
 294         return 0;
 295 }
 296
 297 static int
 298 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 299 {
 300         spin_lock_bh(&inst->lock);
 301         inst->qthreshold = qthresh;
 302         spin_unlock_bh(&inst->lock);
 303
 304         return 0;
 305 }
 306
 307 static int
 308 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 309 {
 310         spin_lock_bh(&inst->lock);
 311         inst->flags = flags;
 312         spin_unlock_bh(&inst->lock);
 313
 314         return 0;
 315 }
 316
 317 static struct sk_buff *nfulnl_alloc_skb(unsigned int inst_size,
 318                                         unsigned int pkt_size)
 319 {
 320         struct sk_buff *skb;
 321         unsigned int n;
 322
 323         UDEBUG("entered (%u, %u)\n", inst_size, pkt_size);
 324
 325         /* alloc skb which should be big enough for a whole multipart
 326          * message.  WARNING: has to be <= 128k due to slab restrictions */
 327
 328         n = max(inst_size, pkt_size);
 329         skb = alloc_skb(n, GFP_ATOMIC);
 330         if (!skb) {
 331                 PRINTR("nfnetlink_log: can't alloc whole buffer (%u bytes)\n",
 332                         inst_size);
 333
 334                 if (n > pkt_size) {
 335                         /* try to allocate only as much as we need for current
 336                          * packet */
 337
 338                         skb = alloc_skb(pkt_size, GFP_ATOMIC);
 339                         if (!skb)
 340                                 PRINTR("nfnetlink_log: can't even alloc %u "
 341                                        "bytes\n", pkt_size);
 342                 }
 343         }
 344
 345         return skb;
 346 }
 347
 348 static int
 349 __nfulnl_send(struct nfulnl_instance *inst)
 350 {
 351         int status;
 352
 353         if (inst->qlen > 1)
 354                 inst->lastnlh->nlmsg_type = NLMSG_DONE;
 355
 356         status = nfnetlink_unicast(inst->skb, inst->peer_pid, MSG_DONTWAIT);
 357         if (status < 0) {
 358                 UDEBUG("netlink_unicast() failed\n");
 359                 /* FIXME: statistics */
 360         }
 361
 362         inst->qlen = 0;
 363         inst->skb = NULL;
 364         inst->lastnlh = NULL;
 365
 366         return status;
 367 }
 368
 369 static void nfulnl_timer(unsigned long data)
 370 {
 371         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 372
 373         UDEBUG("timer function called, flushing buffer\n");
 374
 375         spin_lock_bh(&inst->lock);
 376         if (inst->skb)
 377                 __nfulnl_send(inst);
 378         spin_unlock_bh(&inst->lock);
 379         instance_put(inst);
 380 }
 381
 382 /* This is an inline function, we don't really care about a long
 383  * list of arguments */
 384 static inline int
 385 __build_packet_message(struct nfulnl_instance *inst,
 386                         const struct sk_buff *skb,
 387                         unsigned int data_len,
 388                         unsigned int pf,
 389                         unsigned int hooknum,
 390                         const struct net_device *indev,
 391                         const struct net_device *outdev,
 392                         const struct nf_loginfo *li,
 393                         const char *prefix, unsigned int plen)
 394 {
 395         struct nfulnl_msg_packet_hdr pmsg;
 396         struct nlmsghdr *nlh;
 397         struct nfgenmsg *nfmsg;
 398         __be32 tmp_uint;
 399         sk_buff_data_t old_tail = inst->skb->tail;
 400
 401         UDEBUG("entered\n");
 402
 403         nlh = NLMSG_PUT(inst->skb, 0, 0,
 404                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 405                         sizeof(struct nfgenmsg));
 406         nfmsg = NLMSG_DATA(nlh);
 407         nfmsg->nfgen_family = pf;
 408         nfmsg->version = NFNETLINK_V0;
 409         nfmsg->res_id = htons(inst->group_num);
 410
 411         pmsg.hw_protocol        = skb->protocol;
 412         pmsg.hook               = hooknum;
 413
 414         NFA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
 415
 416         if (prefix)
 417                 NFA_PUT(inst->skb, NFULA_PREFIX, plen, prefix);
 418
 419         if (indev) {
 420                 tmp_uint = htonl(indev->ifindex);
 421 #ifndef CONFIG_BRIDGE_NETFILTER
 422                 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV, sizeof(tmp_uint),
 423                         &tmp_uint);
 424 #else
 425                 if (pf == PF_BRIDGE) {
 426                         /* Case 1: outdev is physical input device, we need to
 427                          * look for bridge group (when called from
 428                          * netfilter_bridge) */
 429                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 430                                 sizeof(tmp_uint), &tmp_uint);
 431                         /* this is the bridge group "brX" */
 432                         tmp_uint = htonl(indev->br_port->br->dev->ifindex);
 433                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
 434                                 sizeof(tmp_uint), &tmp_uint);
 435                 } else {
 436                         /* Case 2: indev is bridge group, we need to look for
 437                          * physical device (when called from ipv4) */
 438                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
 439                                 sizeof(tmp_uint), &tmp_uint);
 440                         if (skb->nf_bridge && skb->nf_bridge->physindev) {
 441                                 tmp_uint =
 442                                     htonl(skb->nf_bridge->physindev->ifindex);
 443                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 444                                         sizeof(tmp_uint), &tmp_uint);
 445                         }
 446                 }
 447 #endif
 448         }
 449
 450         if (outdev) {
 451                 tmp_uint = htonl(outdev->ifindex);
 452 #ifndef CONFIG_BRIDGE_NETFILTER
 453                 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV, sizeof(tmp_uint),
 454                         &tmp_uint);
 455 #else
 456                 if (pf == PF_BRIDGE) {
 457                         /* Case 1: outdev is physical output device, we need to
 458                          * look for bridge group (when called from
 459                          * netfilter_bridge) */
 460                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 461                                 sizeof(tmp_uint), &tmp_uint);
 462                         /* this is the bridge group "brX" */
 463                         tmp_uint = htonl(outdev->br_port->br->dev->ifindex);
 464                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
 465                                 sizeof(tmp_uint), &tmp_uint);
 466                 } else {
 467                         /* Case 2: indev is a bridge group, we need to look
 468                          * for physical device (when called from ipv4) */
 469                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
 470                                 sizeof(tmp_uint), &tmp_uint);
 471                         if (skb->nf_bridge && skb->nf_bridge->physoutdev) {
 472                                 tmp_uint =
 473                                     htonl(skb->nf_bridge->physoutdev->ifindex);
 474                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 475                                         sizeof(tmp_uint), &tmp_uint);
 476                         }
 477                 }
 478 #endif
 479         }
 480
 481         if (skb->mark) {
 482                 tmp_uint = htonl(skb->mark);
 483                 NFA_PUT(inst->skb, NFULA_MARK, sizeof(tmp_uint), &tmp_uint);
 484         }
 485
 486         if (indev && skb->dev && skb->dev->hard_header_parse) {
 487                 struct nfulnl_msg_packet_hw phw;
 488                 int len = skb->dev->hard_header_parse((struct sk_buff *)skb,
 489                                                     phw.hw_addr);
 490                 phw.hw_addrlen = htons(len);
 491                 NFA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
 492         }
 493
 494         if (skb->tstamp.tv64) {
 495                 struct nfulnl_msg_packet_timestamp ts;
 496                 struct timeval tv = ktime_to_timeval(skb->tstamp);
 497                 ts.sec = cpu_to_be64(tv.tv_sec);
 498                 ts.usec = cpu_to_be64(tv.tv_usec);
 499
 500                 NFA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
 501         }
 502
 503         /* UID */
 504         if (skb->sk) {
 505                 read_lock_bh(&skb->sk->sk_callback_lock);
 506                 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
 507                         __be32 uid = htonl(skb->sk->sk_socket->file->f_uid);
 508                         /* need to unlock here since NFA_PUT may goto */
 509                         read_unlock_bh(&skb->sk->sk_callback_lock);
 510                         NFA_PUT(inst->skb, NFULA_UID, sizeof(uid), &uid);
 511                 } else
 512                         read_unlock_bh(&skb->sk->sk_callback_lock);
 513         }
 514
 515         /* local sequence number */
 516         if (inst->flags & NFULNL_CFG_F_SEQ) {
 517                 tmp_uint = htonl(inst->seq++);
 518                 NFA_PUT(inst->skb, NFULA_SEQ, sizeof(tmp_uint), &tmp_uint);
 519         }
 520         /* global sequence number */
 521         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) {
 522                 tmp_uint = htonl(atomic_inc_return(&global_seq));
 523                 NFA_PUT(inst->skb, NFULA_SEQ_GLOBAL, sizeof(tmp_uint), &tmp_uint);
 524         }
 525
 526         if (data_len) {
 527                 struct nfattr *nfa;
 528                 int size = NFA_LENGTH(data_len);
 529
 530                 if (skb_tailroom(inst->skb) < (int)NFA_SPACE(data_len)) {
 531                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
 532                         goto nlmsg_failure;
 533                 }
 534
 535                 nfa = (struct nfattr *)skb_put(inst->skb, NFA_ALIGN(size));
 536                 nfa->nfa_type = NFULA_PAYLOAD;
 537                 nfa->nfa_len = size;
 538
 539                 if (skb_copy_bits(skb, 0, NFA_DATA(nfa), data_len))
 540                         BUG();
 541         }
 542
 543         nlh->nlmsg_len = inst->skb->tail - old_tail;
 544         inst->lastnlh = nlh;
 545         return 0;
 546
 547 nlmsg_failure:
 548         UDEBUG("nlmsg_failure\n");
 549 nfattr_failure:
 550         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 551         return -1;
 552 }
 553
 554 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 555
 556 static struct nf_loginfo default_loginfo = {
 557         .type =         NF_LOG_TYPE_ULOG,
 558         .u = {
 559                 .ulog = {
 560                         .copy_len       = 0xffff,
 561                         .group          = 0,
 562                         .qthreshold     = 1,
 563                 },
 564         },
 565 };
 566
 567 /* log handler for internal netfilter logging api */
 568 static void
 569 nfulnl_log_packet(unsigned int pf,
 570                   unsigned int hooknum,
 571                   const struct sk_buff *skb,
 572                   const struct net_device *in,
 573                   const struct net_device *out,
 574                   const struct nf_loginfo *li_user,
 575                   const char *prefix)
 576 {
 577         unsigned int size, data_len;
 578         struct nfulnl_instance *inst;
 579         const struct nf_loginfo *li;
 580         unsigned int qthreshold;
 581         unsigned int plen;
 582
 583         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 584                 li = li_user;
 585         else
 586                 li = &default_loginfo;
 587
 588         inst = instance_lookup_get(li->u.ulog.group);
 589         if (!inst)
 590                 inst = instance_lookup_get(0);
 591         if (!inst) {
 592                 PRINTR("nfnetlink_log: trying to log packet, "
 593                         "but no instance for group %u\n", li->u.ulog.group);
 594                 return;
 595         }
 596
 597         plen = 0;
 598         if (prefix)
 599                 plen = strlen(prefix) + 1;
 600
 601         /* all macros expand to constant values at compile time */
 602         /* FIXME: do we want to make the size calculation conditional based on
 603          * what is actually present?  way more branches and checks, but more
 604          * memory efficient... */
 605         size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
 606                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hdr))
 607                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 608                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 609 #ifdef CONFIG_BRIDGE_NETFILTER
 610                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 611                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 612 #endif
 613                 + NFA_SPACE(sizeof(u_int32_t))  /* mark */
 614                 + NFA_SPACE(sizeof(u_int32_t))  /* uid */
 615                 + NFA_SPACE(plen)               /* prefix */
 616                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hw))
 617                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_timestamp));
 618
 619         UDEBUG("initial size=%u\n", size);
 620
 621         spin_lock_bh(&inst->lock);
 622
 623         if (inst->flags & NFULNL_CFG_F_SEQ)
 624                 size += NFA_SPACE(sizeof(u_int32_t));
 625         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 626                 size += NFA_SPACE(sizeof(u_int32_t));
 627
 628         qthreshold = inst->qthreshold;
 629         /* per-rule qthreshold overrides per-instance */
 630         if (qthreshold > li->u.ulog.qthreshold)
 631                 qthreshold = li->u.ulog.qthreshold;
 632
 633         switch (inst->copy_mode) {
 634         case NFULNL_COPY_META:
 635         case NFULNL_COPY_NONE:
 636                 data_len = 0;
 637                 break;
 638
 639         case NFULNL_COPY_PACKET:
 640                 if (inst->copy_range == 0
 641                     || inst->copy_range > skb->len)
 642                         data_len = skb->len;
 643                 else
 644                         data_len = inst->copy_range;
 645
 646                 size += NFA_SPACE(data_len);
 647                 UDEBUG("copy_packet, therefore size now %u\n", size);
 648                 break;
 649
 650         default:
 651                 goto unlock_and_release;
 652         }
 653
 654         if (inst->qlen >= qthreshold ||
 655             (inst->skb && size > skb_tailroom(inst->skb))) {
 656                 /* either the queue len is too high or we don't have
 657                  * enough room in the skb left. flush to userspace. */
 658                 UDEBUG("flushing old skb\n");
 659
 660                 /* timer "holds" one reference (we have another one) */
 661                 if (del_timer(&inst->timer))
 662                         instance_put(inst);
 663                 __nfulnl_send(inst);
 664         }
 665
 666         if (!inst->skb) {
 667                 inst->skb = nfulnl_alloc_skb(inst->nlbufsiz, size);
 668                 if (!inst->skb)
 669                         goto alloc_failure;
 670         }
 671
 672         UDEBUG("qlen %d, qthreshold %d\n", inst->qlen, qthreshold);
 673         inst->qlen++;
 674
 675         __build_packet_message(inst, skb, data_len, pf,
 676                                 hooknum, in, out, li, prefix, plen);
 677
 678         /* timer_pending always called within inst->lock, so there
 679          * is no chance of a race here */
 680         if (!timer_pending(&inst->timer)) {
 681                 instance_get(inst);
 682                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 683                 add_timer(&inst->timer);
 684         }
 685
 686 unlock_and_release:
 687         spin_unlock_bh(&inst->lock);
 688         instance_put(inst);
 689         return;
 690
 691 alloc_failure:
 692         UDEBUG("error allocating skb\n");
 693         /* FIXME: statistics */
 694         goto unlock_and_release;
 695 }
 696
 697 static int
 698 nfulnl_rcv_nl_event(struct notifier_block *this,
 699                    unsigned long event, void *ptr)
 700 {
 701         struct netlink_notify *n = ptr;
 702
 703         if (event == NETLINK_URELEASE &&
 704             n->protocol == NETLINK_NETFILTER && n->pid) {
 705                 int i;
 706
 707                 /* destroy all instances for this pid */
 708                 write_lock_bh(&instances_lock);
 709                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 710                         struct hlist_node *tmp, *t2;
 711                         struct nfulnl_instance *inst;
 712                         struct hlist_head *head = &instance_table[i];
 713
 714                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
 715                                 UDEBUG("node = %p\n", inst);
 716                                 if (n->pid == inst->peer_pid)
 717                                         __instance_destroy(inst);
 718                         }
 719                 }
 720                 write_unlock_bh(&instances_lock);
 721         }
 722         return NOTIFY_DONE;
 723 }
 724
 725 static struct notifier_block nfulnl_rtnl_notifier = {
 726         .notifier_call  = nfulnl_rcv_nl_event,
 727 };
 728
 729 static int
 730 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 731                   struct nlmsghdr *nlh, struct nfattr *nfqa[])
 732 {
 733         return -ENOTSUPP;
 734 }
 735
 736 static struct nf_logger nfulnl_logger = {
 737         .name   = "nfnetlink_log",
 738         .logfn  = &nfulnl_log_packet,
 739         .me     = THIS_MODULE,
 740 };
 741
 742 static const int nfula_min[NFULA_MAX] = {
 743         [NFULA_PACKET_HDR-1]    = sizeof(struct nfulnl_msg_packet_hdr),
 744         [NFULA_MARK-1]          = sizeof(u_int32_t),
 745         [NFULA_TIMESTAMP-1]     = sizeof(struct nfulnl_msg_packet_timestamp),
 746         [NFULA_IFINDEX_INDEV-1] = sizeof(u_int32_t),
 747         [NFULA_IFINDEX_OUTDEV-1]= sizeof(u_int32_t),
 748         [NFULA_IFINDEX_PHYSINDEV-1]     = sizeof(u_int32_t),
 749         [NFULA_IFINDEX_PHYSOUTDEV-1]    = sizeof(u_int32_t),
 750         [NFULA_HWADDR-1]        = sizeof(struct nfulnl_msg_packet_hw),
 751         [NFULA_PAYLOAD-1]       = 0,
 752         [NFULA_PREFIX-1]        = 0,
 753         [NFULA_UID-1]           = sizeof(u_int32_t),
 754         [NFULA_SEQ-1]           = sizeof(u_int32_t),
 755         [NFULA_SEQ_GLOBAL-1]    = sizeof(u_int32_t),
 756 };
 757
 758 static const int nfula_cfg_min[NFULA_CFG_MAX] = {
 759         [NFULA_CFG_CMD-1]       = sizeof(struct nfulnl_msg_config_cmd),
 760         [NFULA_CFG_MODE-1]      = sizeof(struct nfulnl_msg_config_mode),
 761         [NFULA_CFG_TIMEOUT-1]   = sizeof(u_int32_t),
 762         [NFULA_CFG_QTHRESH-1]   = sizeof(u_int32_t),
 763         [NFULA_CFG_NLBUFSIZ-1]  = sizeof(u_int32_t),
 764         [NFULA_CFG_FLAGS-1]     = sizeof(u_int16_t),
 765 };
 766
 767 static int
 768 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 769                    struct nlmsghdr *nlh, struct nfattr *nfula[])
 770 {
 771         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 772         u_int16_t group_num = ntohs(nfmsg->res_id);
 773         struct nfulnl_instance *inst;
 774         int ret = 0;
 775
 776         UDEBUG("entering for msg %u\n", NFNL_MSG_TYPE(nlh->nlmsg_type));
 777
 778         if (nfattr_bad_size(nfula, NFULA_CFG_MAX, nfula_cfg_min)) {
 779                 UDEBUG("bad attribute size\n");
 780                 return -EINVAL;
 781         }
 782
 783         inst = instance_lookup_get(group_num);
 784         if (nfula[NFULA_CFG_CMD-1]) {
 785                 u_int8_t pf = nfmsg->nfgen_family;
 786                 struct nfulnl_msg_config_cmd *cmd;
 787                 cmd = NFA_DATA(nfula[NFULA_CFG_CMD-1]);
 788                 UDEBUG("found CFG_CMD for\n");
 789
 790                 switch (cmd->command) {
 791                 case NFULNL_CFG_CMD_BIND:
 792                         if (inst) {
 793                                 ret = -EBUSY;
 794                                 goto out_put;
 795                         }
 796
 797                         inst = instance_create(group_num,
 798                                                NETLINK_CB(skb).pid);
 799                         if (!inst) {
 800                                 ret = -EINVAL;
 801                                 goto out;
 802                         }
 803                         break;
 804                 case NFULNL_CFG_CMD_UNBIND:
 805                         if (!inst) {
 806                                 ret = -ENODEV;
 807                                 goto out;
 808                         }
 809
 810                         if (inst->peer_pid != NETLINK_CB(skb).pid) {
 811                                 ret = -EPERM;
 812                                 goto out_put;
 813                         }
 814
 815                         instance_destroy(inst);
 816                         goto out;
 817                 case NFULNL_CFG_CMD_PF_BIND:
 818                         UDEBUG("registering log handler for pf=%u\n", pf);
 819                         ret = nf_log_register(pf, &nfulnl_logger);
 820                         break;
 821                 case NFULNL_CFG_CMD_PF_UNBIND:
 822                         UDEBUG("unregistering log handler for pf=%u\n", pf);
 823                         /* This is a bug and a feature.  We cannot unregister
 824                          * other handlers, like nfnetlink_inst can */
 825                         nf_log_unregister_pf(pf);
 826                         break;
 827                 default:
 828                         ret = -EINVAL;
 829                         break;
 830                 }
 831
 832                 if (!inst)
 833                         goto out;
 834         } else {
 835                 if (!inst) {
 836                         UDEBUG("no config command, and no instance for "
 837                                 "group=%u pid=%u =>ENOENT\n",
 838                                 group_num, NETLINK_CB(skb).pid);
 839                         ret = -ENOENT;
 840                         goto out;
 841                 }
 842
 843                 if (inst->peer_pid != NETLINK_CB(skb).pid) {
 844                         UDEBUG("no config command, and wrong pid\n");
 845                         ret = -EPERM;
 846                         goto out_put;
 847                 }
 848         }
 849
 850         if (nfula[NFULA_CFG_MODE-1]) {
 851                 struct nfulnl_msg_config_mode *params;
 852                 params = NFA_DATA(nfula[NFULA_CFG_MODE-1]);
 853
 854                 nfulnl_set_mode(inst, params->copy_mode,
 855                                 ntohl(params->copy_range));
 856         }
 857
 858         if (nfula[NFULA_CFG_TIMEOUT-1]) {
 859                 __be32 timeout =
 860                         *(__be32 *)NFA_DATA(nfula[NFULA_CFG_TIMEOUT-1]);
 861
 862                 nfulnl_set_timeout(inst, ntohl(timeout));
 863         }
 864
 865         if (nfula[NFULA_CFG_NLBUFSIZ-1]) {
 866                 __be32 nlbufsiz =
 867                         *(__be32 *)NFA_DATA(nfula[NFULA_CFG_NLBUFSIZ-1]);
 868
 869                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 870         }
 871
 872         if (nfula[NFULA_CFG_QTHRESH-1]) {
 873                 __be32 qthresh =
 874                         *(__be32 *)NFA_DATA(nfula[NFULA_CFG_QTHRESH-1]);
 875
 876                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 877         }
 878
 879         if (nfula[NFULA_CFG_FLAGS-1]) {
 880                 __be16 flags =
 881                         *(__be16 *)NFA_DATA(nfula[NFULA_CFG_FLAGS-1]);
 882                 nfulnl_set_flags(inst, ntohs(flags));
 883         }
 884
 885 out_put:
 886         instance_put(inst);
 887 out:
 888         return ret;
 889 }
 890
 891 static struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 892         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 893                                     .attr_count = NFULA_MAX, },
 894         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 895                                     .attr_count = NFULA_CFG_MAX, },
 896 };
 897
 898 static struct nfnetlink_subsystem nfulnl_subsys = {
 899         .name           = "log",
 900         .subsys_id      = NFNL_SUBSYS_ULOG,
 901         .cb_count       = NFULNL_MSG_MAX,
 902         .cb             = nfulnl_cb,
 903 };
 904
 905 #ifdef CONFIG_PROC_FS
 906 struct iter_state {
 907         unsigned int bucket;
 908 };
 909
 910 static struct hlist_node *get_first(struct iter_state *st)
 911 {
 912         if (!st)
 913                 return NULL;
 914
 915         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 916                 if (!hlist_empty(&instance_table[st->bucket]))
 917                         return instance_table[st->bucket].first;
 918         }
 919         return NULL;
 920 }
 921
 922 static struct hlist_node *get_next(struct iter_state *st, struct hlist_node *h)
 923 {
 924         h = h->next;
 925         while (!h) {
 926                 if (++st->bucket >= INSTANCE_BUCKETS)
 927                         return NULL;
 928
 929                 h = instance_table[st->bucket].first;
 930         }
 931         return h;
 932 }
 933
 934 static struct hlist_node *get_idx(struct iter_state *st, loff_t pos)
 935 {
 936         struct hlist_node *head;
 937         head = get_first(st);
 938
 939         if (head)
 940                 while (pos && (head = get_next(st, head)))
 941                         pos--;
 942         return pos ? NULL : head;
 943 }
 944
 945 static void *seq_start(struct seq_file *seq, loff_t *pos)
 946 {
 947         read_lock_bh(&instances_lock);
 948         return get_idx(seq->private, *pos);
 949 }
 950
 951 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 952 {
 953         (*pos)++;
 954         return get_next(s->private, v);
 955 }
 956
 957 static void seq_stop(struct seq_file *s, void *v)
 958 {
 959         read_unlock_bh(&instances_lock);
 960 }
 961
 962 static int seq_show(struct seq_file *s, void *v)
 963 {
 964         const struct nfulnl_instance *inst = v;
 965
 966         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
 967                           inst->group_num,
 968                           inst->peer_pid, inst->qlen,
 969                           inst->copy_mode, inst->copy_range,
 970                           inst->flushtimeout, atomic_read(&inst->use));
 971 }
 972
 973 static struct seq_operations nful_seq_ops = {
 974         .start  = seq_start,
 975         .next   = seq_next,
 976         .stop   = seq_stop,
 977         .show   = seq_show,
 978 };
 979
 980 static int nful_open(struct inode *inode, struct file *file)
 981 {
 982         struct seq_file *seq;
 983         struct iter_state *is;
 984         int ret;
 985
 986         is = kzalloc(sizeof(*is), GFP_KERNEL);
 987         if (!is)
 988                 return -ENOMEM;
 989         ret = seq_open(file, &nful_seq_ops);
 990         if (ret < 0)
 991                 goto out_free;
 992         seq = file->private_data;
 993         seq->private = is;
 994         return ret;
 995 out_free:
 996         kfree(is);
 997         return ret;
 998 }
 999
1000 static const struct file_operations nful_file_ops = {
1001         .owner   = THIS_MODULE,
1002         .open    = nful_open,
1003         .read    = seq_read,
1004         .llseek  = seq_lseek,
1005         .release = seq_release_private,
1006 };
1007
1008 #endif /* PROC_FS */
1009
1010 static int __init nfnetlink_log_init(void)
1011 {
1012         int i, status = -ENOMEM;
1013 #ifdef CONFIG_PROC_FS
1014         struct proc_dir_entry *proc_nful;
1015 #endif
1016
1017         for (i = 0; i < INSTANCE_BUCKETS; i++)
1018                 INIT_HLIST_HEAD(&instance_table[i]);
1019
1020         /* it's not really all that important to have a random value, so
1021          * we can do this from the init function, even if there hasn't
1022          * been that much entropy yet */
1023         get_random_bytes(&hash_init, sizeof(hash_init));
1024
1025         netlink_register_notifier(&nfulnl_rtnl_notifier);
1026         status = nfnetlink_subsys_register(&nfulnl_subsys);
1027         if (status < 0) {
1028                 printk(KERN_ERR "log: failed to create netlink socket\n");
1029                 goto cleanup_netlink_notifier;
1030         }
1031
1032 #ifdef CONFIG_PROC_FS
1033         proc_nful = create_proc_entry("nfnetlink_log", 0440,
1034                                       proc_net_netfilter);
1035         if (!proc_nful)
1036                 goto cleanup_subsys;
1037         proc_nful->proc_fops = &nful_file_ops;
1038 #endif
1039         return status;
1040
1041 #ifdef CONFIG_PROC_FS
1042 cleanup_subsys:
1043         nfnetlink_subsys_unregister(&nfulnl_subsys);
1044 #endif
1045 cleanup_netlink_notifier:
1046         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1047         return status;
1048 }
1049
1050 static void __exit nfnetlink_log_fini(void)
1051 {
1052         nf_log_unregister(&nfulnl_logger);
1053 #ifdef CONFIG_PROC_FS
1054         remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1055 #endif
1056         nfnetlink_subsys_unregister(&nfulnl_subsys);
1057         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1058 }
1059
1060 MODULE_DESCRIPTION("netfilter userspace logging");
1061 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1062 MODULE_LICENSE("GPL");
1063 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1064
1065 module_init(nfnetlink_log_init);
1066 module_exit(nfnetlink_log_fini);