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  * 2006-01-26 Harald Welte <laforge@netfilter.org>
  15  *      - Add optional local and global sequence number to detect lost
  16  *        events from userspace
  17  *
  18  */
  19 #include <linux/module.h>
  20 #include <linux/skbuff.h>
  21 #include <linux/init.h>
  22 #include <linux/ip.h>
  23 #include <linux/ipv6.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/netfilter.h>
  26 #include <linux/netlink.h>
  27 #include <linux/netfilter/nfnetlink.h>
  28 #include <linux/netfilter/nfnetlink_log.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/sysctl.h>
  31 #include <linux/proc_fs.h>
  32 #include <linux/security.h>
  33 #include <linux/list.h>
  34 #include <linux/jhash.h>
  35 #include <linux/random.h>
  36 #include <net/sock.h>
  37
  38 #include <asm/atomic.h>
  39
  40 #ifdef CONFIG_BRIDGE_NETFILTER
  41 #include "../bridge/br_private.h"
  42 #endif
  43
  44 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  45 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  46 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  47
  48 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
  49                                      printk(x, ## args); } while (0);
  50
  51 #if 0
  52 #define UDEBUG(x, args ...)     printk(KERN_DEBUG "%s(%d):%s(): " x,       \
  53                                         __FILE__, __LINE__, __FUNCTION__,  \
  54                                         ## args)
  55 #else
  56 #define UDEBUG(x, ...)
  57 #endif
  58
  59 struct nfulnl_instance {
  60         struct hlist_node hlist;        /* global list of instances */
  61         spinlock_t lock;
  62         atomic_t use;                   /* use count */
  63
  64         unsigned int qlen;              /* number of nlmsgs in skb */
  65         struct sk_buff *skb;            /* pre-allocatd skb */
  66         struct nlmsghdr *lastnlh;       /* netlink header of last msg in skb */
  67         struct timer_list timer;
  68         int peer_pid;                   /* PID of the peer process */
  69
  70         /* configurable parameters */
  71         unsigned int flushtimeout;      /* timeout until queue flush */
  72         unsigned int nlbufsiz;          /* netlink buffer allocation size */
  73         unsigned int qthreshold;        /* threshold of the queue */
  74         u_int32_t copy_range;
  75         u_int32_t seq;                  /* instance-local sequential counter */
  76         u_int16_t group_num;            /* number of this queue */
  77         u_int16_t flags;
  78         u_int8_t copy_mode;
  79 };
  80
  81 static DEFINE_RWLOCK(instances_lock);
  82 static atomic_t global_seq;
  83
  84 #define INSTANCE_BUCKETS        16
  85 static struct hlist_head instance_table[INSTANCE_BUCKETS];
  86 static unsigned int hash_init;
  87
  88 static inline u_int8_t instance_hashfn(u_int16_t group_num)
  89 {
  90         return ((group_num & 0xff) % INSTANCE_BUCKETS);
  91 }
  92
  93 static struct nfulnl_instance *
  94 __instance_lookup(u_int16_t group_num)
  95 {
  96         struct hlist_head *head;
  97         struct hlist_node *pos;
  98         struct nfulnl_instance *inst;
  99
 100         UDEBUG("entering (group_num=%u)\n", group_num);
 101
 102         head = &instance_table[instance_hashfn(group_num)];
 103         hlist_for_each_entry(inst, pos, head, hlist) {
 104                 if (inst->group_num == group_num)
 105                         return inst;
 106         }
 107         return NULL;
 108 }
 109
 110 static inline void
 111 instance_get(struct nfulnl_instance *inst)
 112 {
 113         atomic_inc(&inst->use);
 114 }
 115
 116 static struct nfulnl_instance *
 117 instance_lookup_get(u_int16_t group_num)
 118 {
 119         struct nfulnl_instance *inst;
 120
 121         read_lock_bh(&instances_lock);
 122         inst = __instance_lookup(group_num);
 123         if (inst)
 124                 instance_get(inst);
 125         read_unlock_bh(&instances_lock);
 126
 127         return inst;
 128 }
 129
 130 static void
 131 instance_put(struct nfulnl_instance *inst)
 132 {
 133         if (inst && atomic_dec_and_test(&inst->use)) {
 134                 UDEBUG("kfree(inst=%p)\n", inst);
 135                 kfree(inst);
 136                 module_put(THIS_MODULE);
 137         }
 138 }
 139
 140 static void nfulnl_timer(unsigned long data);
 141
 142 static struct nfulnl_instance *
 143 instance_create(u_int16_t group_num, int pid)
 144 {
 145         struct nfulnl_instance *inst;
 146
 147         UDEBUG("entering (group_num=%u, pid=%d)\n", group_num,
 148                 pid);
 149
 150         write_lock_bh(&instances_lock);
 151         if (__instance_lookup(group_num)) {
 152                 inst = NULL;
 153                 UDEBUG("aborting, instance already exists\n");
 154                 goto out_unlock;
 155         }
 156
 157         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 158         if (!inst)
 159                 goto out_unlock;
 160
 161         INIT_HLIST_NODE(&inst->hlist);
 162         spin_lock_init(&inst->lock);
 163         /* needs to be two, since we _put() after creation */
 164         atomic_set(&inst->use, 2);
 165
 166         init_timer(&inst->timer);
 167         inst->timer.function = nfulnl_timer;
 168         inst->timer.data = (unsigned long)inst;
 169         /* don't start timer yet. (re)start it  with every packet */
 170
 171         inst->peer_pid = pid;
 172         inst->group_num = group_num;
 173
 174         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 175         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 176         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 177         inst->copy_mode         = NFULNL_COPY_PACKET;
 178         inst->copy_range        = 0xffff;
 179
 180         if (!try_module_get(THIS_MODULE))
 181                 goto out_free;
 182
 183         hlist_add_head(&inst->hlist,
 184                        &instance_table[instance_hashfn(group_num)]);
 185
 186         UDEBUG("newly added node: %p, next=%p\n", &inst->hlist,
 187                 inst->hlist.next);
 188
 189         write_unlock_bh(&instances_lock);
 190
 191         return inst;
 192
 193 out_free:
 194         instance_put(inst);
 195 out_unlock:
 196         write_unlock_bh(&instances_lock);
 197         return NULL;
 198 }
 199
 200 static int __nfulnl_send(struct nfulnl_instance *inst);
 201
 202 static void
 203 _instance_destroy2(struct nfulnl_instance *inst, int lock)
 204 {
 205         /* first pull it out of the global list */
 206         if (lock)
 207                 write_lock_bh(&instances_lock);
 208
 209         UDEBUG("removing instance %p (queuenum=%u) from hash\n",
 210                 inst, inst->group_num);
 211
 212         hlist_del(&inst->hlist);
 213
 214         if (lock)
 215                 write_unlock_bh(&instances_lock);
 216
 217         /* then flush all pending packets from skb */
 218
 219         spin_lock_bh(&inst->lock);
 220         if (inst->skb) {
 221                 if (inst->qlen)
 222                         __nfulnl_send(inst);
 223                 if (inst->skb) {
 224                         kfree_skb(inst->skb);
 225                         inst->skb = NULL;
 226                 }
 227         }
 228         spin_unlock_bh(&inst->lock);
 229
 230         /* and finally put the refcount */
 231         instance_put(inst);
 232 }
 233
 234 static inline void
 235 __instance_destroy(struct nfulnl_instance *inst)
 236 {
 237         _instance_destroy2(inst, 0);
 238 }
 239
 240 static inline void
 241 instance_destroy(struct nfulnl_instance *inst)
 242 {
 243         _instance_destroy2(inst, 1);
 244 }
 245
 246 static int
 247 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 248                   unsigned int range)
 249 {
 250         int status = 0;
 251
 252         spin_lock_bh(&inst->lock);
 253
 254         switch (mode) {
 255         case NFULNL_COPY_NONE:
 256         case NFULNL_COPY_META:
 257                 inst->copy_mode = mode;
 258                 inst->copy_range = 0;
 259                 break;
 260
 261         case NFULNL_COPY_PACKET:
 262                 inst->copy_mode = mode;
 263                 /* we're using struct nfattr which has 16bit nfa_len */
 264                 if (range > 0xffff)
 265                         inst->copy_range = 0xffff;
 266                 else
 267                         inst->copy_range = range;
 268                 break;
 269
 270         default:
 271                 status = -EINVAL;
 272                 break;
 273         }
 274
 275         spin_unlock_bh(&inst->lock);
 276
 277         return status;
 278 }
 279
 280 static int
 281 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 282 {
 283         int status;
 284
 285         spin_lock_bh(&inst->lock);
 286         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 287                 status = -ERANGE;
 288         else if (nlbufsiz > 131072)
 289                 status = -ERANGE;
 290         else {
 291                 inst->nlbufsiz = nlbufsiz;
 292                 status = 0;
 293         }
 294         spin_unlock_bh(&inst->lock);
 295
 296         return status;
 297 }
 298
 299 static int
 300 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 301 {
 302         spin_lock_bh(&inst->lock);
 303         inst->flushtimeout = timeout;
 304         spin_unlock_bh(&inst->lock);
 305
 306         return 0;
 307 }
 308
 309 static int
 310 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 311 {
 312         spin_lock_bh(&inst->lock);
 313         inst->qthreshold = qthresh;
 314         spin_unlock_bh(&inst->lock);
 315
 316         return 0;
 317 }
 318
 319 static int
 320 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 321 {
 322         spin_lock_bh(&inst->lock);
 323         inst->flags = flags;
 324         spin_unlock_bh(&inst->lock);
 325
 326         return 0;
 327 }
 328
 329 static struct sk_buff *nfulnl_alloc_skb(unsigned int inst_size,
 330                                         unsigned int pkt_size)
 331 {
 332         struct sk_buff *skb;
 333         unsigned int n;
 334
 335         UDEBUG("entered (%u, %u)\n", inst_size, pkt_size);
 336
 337         /* alloc skb which should be big enough for a whole multipart
 338          * message.  WARNING: has to be <= 128k due to slab restrictions */
 339
 340         n = max(inst_size, pkt_size);
 341         skb = alloc_skb(n, GFP_ATOMIC);
 342         if (!skb) {
 343                 PRINTR("nfnetlink_log: can't alloc whole buffer (%u bytes)\n",
 344                         inst_size);
 345
 346                 if (n > pkt_size) {
 347                         /* try to allocate only as much as we need for current
 348                          * packet */
 349
 350                         skb = alloc_skb(pkt_size, GFP_ATOMIC);
 351                         if (!skb)
 352                                 PRINTR("nfnetlink_log: can't even alloc %u "
 353                                        "bytes\n", pkt_size);
 354                 }
 355         }
 356
 357         return skb;
 358 }
 359
 360 static int
 361 __nfulnl_send(struct nfulnl_instance *inst)
 362 {
 363         int status;
 364
 365         if (timer_pending(&inst->timer))
 366                 del_timer(&inst->timer);
 367
 368         if (!inst->skb)
 369                 return 0;
 370
 371         if (inst->qlen > 1)
 372                 inst->lastnlh->nlmsg_type = NLMSG_DONE;
 373
 374         status = nfnetlink_unicast(inst->skb, inst->peer_pid, MSG_DONTWAIT);
 375         if (status < 0) {
 376                 UDEBUG("netlink_unicast() failed\n");
 377                 /* FIXME: statistics */
 378         }
 379
 380         inst->qlen = 0;
 381         inst->skb = NULL;
 382         inst->lastnlh = NULL;
 383
 384         return status;
 385 }
 386
 387 static void nfulnl_timer(unsigned long data)
 388 {
 389         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 390
 391         UDEBUG("timer function called, flushing buffer\n");
 392
 393         spin_lock_bh(&inst->lock);
 394         __nfulnl_send(inst);
 395         spin_unlock_bh(&inst->lock);
 396         instance_put(inst);
 397 }
 398
 399 /* This is an inline function, we don't really care about a long
 400  * list of arguments */
 401 static inline int
 402 __build_packet_message(struct nfulnl_instance *inst,
 403                         const struct sk_buff *skb,
 404                         unsigned int data_len,
 405                         unsigned int pf,
 406                         unsigned int hooknum,
 407                         const struct net_device *indev,
 408                         const struct net_device *outdev,
 409                         const struct nf_loginfo *li,
 410                         const char *prefix, unsigned int plen)
 411 {
 412         unsigned char *old_tail;
 413         struct nfulnl_msg_packet_hdr pmsg;
 414         struct nlmsghdr *nlh;
 415         struct nfgenmsg *nfmsg;
 416         __be32 tmp_uint;
 417
 418         UDEBUG("entered\n");
 419
 420         old_tail = inst->skb->tail;
 421         nlh = NLMSG_PUT(inst->skb, 0, 0,
 422                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 423                         sizeof(struct nfgenmsg));
 424         nfmsg = NLMSG_DATA(nlh);
 425         nfmsg->nfgen_family = pf;
 426         nfmsg->version = NFNETLINK_V0;
 427         nfmsg->res_id = htons(inst->group_num);
 428
 429         pmsg.hw_protocol        = skb->protocol;
 430         pmsg.hook               = hooknum;
 431
 432         NFA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
 433
 434         if (prefix)
 435                 NFA_PUT(inst->skb, NFULA_PREFIX, plen, prefix);
 436
 437         if (indev) {
 438                 tmp_uint = htonl(indev->ifindex);
 439 #ifndef CONFIG_BRIDGE_NETFILTER
 440                 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV, sizeof(tmp_uint),
 441                         &tmp_uint);
 442 #else
 443                 if (pf == PF_BRIDGE) {
 444                         /* Case 1: outdev is physical input device, we need to
 445                          * look for bridge group (when called from
 446                          * netfilter_bridge) */
 447                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 448                                 sizeof(tmp_uint), &tmp_uint);
 449                         /* this is the bridge group "brX" */
 450                         tmp_uint = htonl(indev->br_port->br->dev->ifindex);
 451                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
 452                                 sizeof(tmp_uint), &tmp_uint);
 453                 } else {
 454                         /* Case 2: indev is bridge group, we need to look for
 455                          * physical device (when called from ipv4) */
 456                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
 457                                 sizeof(tmp_uint), &tmp_uint);
 458                         if (skb->nf_bridge && skb->nf_bridge->physindev) {
 459                                 tmp_uint =
 460                                     htonl(skb->nf_bridge->physindev->ifindex);
 461                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 462                                         sizeof(tmp_uint), &tmp_uint);
 463                         }
 464                 }
 465 #endif
 466         }
 467
 468         if (outdev) {
 469                 tmp_uint = htonl(outdev->ifindex);
 470 #ifndef CONFIG_BRIDGE_NETFILTER
 471                 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV, sizeof(tmp_uint),
 472                         &tmp_uint);
 473 #else
 474                 if (pf == PF_BRIDGE) {
 475                         /* Case 1: outdev is physical output device, we need to
 476                          * look for bridge group (when called from
 477                          * netfilter_bridge) */
 478                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 479                                 sizeof(tmp_uint), &tmp_uint);
 480                         /* this is the bridge group "brX" */
 481                         tmp_uint = htonl(outdev->br_port->br->dev->ifindex);
 482                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
 483                                 sizeof(tmp_uint), &tmp_uint);
 484                 } else {
 485                         /* Case 2: indev is a bridge group, we need to look
 486                          * for physical device (when called from ipv4) */
 487                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
 488                                 sizeof(tmp_uint), &tmp_uint);
 489                         if (skb->nf_bridge) {
 490                                 tmp_uint =
 491                                     htonl(skb->nf_bridge->physoutdev->ifindex);
 492                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 493                                         sizeof(tmp_uint), &tmp_uint);
 494                         }
 495                 }
 496 #endif
 497         }
 498
 499         if (skb->mark) {
 500                 tmp_uint = htonl(skb->mark);
 501                 NFA_PUT(inst->skb, NFULA_MARK, sizeof(tmp_uint), &tmp_uint);
 502         }
 503
 504         if (indev && skb->dev && skb->dev->hard_header_parse) {
 505                 struct nfulnl_msg_packet_hw phw;
 506                 int len = skb->dev->hard_header_parse((struct sk_buff *)skb,
 507                                                     phw.hw_addr);
 508                 phw.hw_addrlen = htons(len);
 509                 NFA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
 510         }
 511
 512         if (skb->tstamp.off_sec) {
 513                 struct nfulnl_msg_packet_timestamp ts;
 514
 515                 ts.sec = cpu_to_be64(skb->tstamp.off_sec);
 516                 ts.usec = cpu_to_be64(skb->tstamp.off_usec);
 517
 518                 NFA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
 519         }
 520
 521         /* UID */
 522         if (skb->sk) {
 523                 read_lock_bh(&skb->sk->sk_callback_lock);
 524                 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
 525                         __be32 uid = htonl(skb->sk->sk_socket->file->f_uid);
 526                         /* need to unlock here since NFA_PUT may goto */
 527                         read_unlock_bh(&skb->sk->sk_callback_lock);
 528                         NFA_PUT(inst->skb, NFULA_UID, sizeof(uid), &uid);
 529                 } else
 530                         read_unlock_bh(&skb->sk->sk_callback_lock);
 531         }
 532
 533         /* local sequence number */
 534         if (inst->flags & NFULNL_CFG_F_SEQ) {
 535                 tmp_uint = htonl(inst->seq++);
 536                 NFA_PUT(inst->skb, NFULA_SEQ, sizeof(tmp_uint), &tmp_uint);
 537         }
 538         /* global sequence number */
 539         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) {
 540                 tmp_uint = htonl(atomic_inc_return(&global_seq));
 541                 NFA_PUT(inst->skb, NFULA_SEQ_GLOBAL, sizeof(tmp_uint), &tmp_uint);
 542         }
 543
 544         if (data_len) {
 545                 struct nfattr *nfa;
 546                 int size = NFA_LENGTH(data_len);
 547
 548                 if (skb_tailroom(inst->skb) < (int)NFA_SPACE(data_len)) {
 549                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
 550                         goto nlmsg_failure;
 551                 }
 552
 553                 nfa = (struct nfattr *)skb_put(inst->skb, NFA_ALIGN(size));
 554                 nfa->nfa_type = NFULA_PAYLOAD;
 555                 nfa->nfa_len = size;
 556
 557                 if (skb_copy_bits(skb, 0, NFA_DATA(nfa), data_len))
 558                         BUG();
 559         }
 560
 561         nlh->nlmsg_len = inst->skb->tail - old_tail;
 562         inst->lastnlh = nlh;
 563         return 0;
 564
 565 nlmsg_failure:
 566         UDEBUG("nlmsg_failure\n");
 567 nfattr_failure:
 568         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 569         return -1;
 570 }
 571
 572 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 573
 574 static struct nf_loginfo default_loginfo = {
 575         .type =         NF_LOG_TYPE_ULOG,
 576         .u = {
 577                 .ulog = {
 578                         .copy_len       = 0xffff,
 579                         .group          = 0,
 580                         .qthreshold     = 1,
 581                 },
 582         },
 583 };
 584
 585 /* log handler for internal netfilter logging api */
 586 static void
 587 nfulnl_log_packet(unsigned int pf,
 588                   unsigned int hooknum,
 589                   const struct sk_buff *skb,
 590                   const struct net_device *in,
 591                   const struct net_device *out,
 592                   const struct nf_loginfo *li_user,
 593                   const char *prefix)
 594 {
 595         unsigned int size, data_len;
 596         struct nfulnl_instance *inst;
 597         const struct nf_loginfo *li;
 598         unsigned int qthreshold;
 599         unsigned int nlbufsiz;
 600         unsigned int plen;
 601
 602         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 603                 li = li_user;
 604         else
 605                 li = &default_loginfo;
 606
 607         inst = instance_lookup_get(li->u.ulog.group);
 608         if (!inst)
 609                 inst = instance_lookup_get(0);
 610         if (!inst) {
 611                 PRINTR("nfnetlink_log: trying to log packet, "
 612                         "but no instance for group %u\n", li->u.ulog.group);
 613                 return;
 614         }
 615
 616         plen = 0;
 617         if (prefix)
 618                 plen = strlen(prefix);
 619
 620         /* all macros expand to constant values at compile time */
 621         /* FIXME: do we want to make the size calculation conditional based on
 622          * what is actually present?  way more branches and checks, but more
 623          * memory efficient... */
 624         size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
 625                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hdr))
 626                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 627                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 628 #ifdef CONFIG_BRIDGE_NETFILTER
 629                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 630                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 631 #endif
 632                 + NFA_SPACE(sizeof(u_int32_t))  /* mark */
 633                 + NFA_SPACE(sizeof(u_int32_t))  /* uid */
 634                 + NFA_SPACE(plen)               /* prefix */
 635                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hw))
 636                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_timestamp));
 637
 638         UDEBUG("initial size=%u\n", size);
 639
 640         spin_lock_bh(&inst->lock);
 641
 642         if (inst->flags & NFULNL_CFG_F_SEQ)
 643                 size += NFA_SPACE(sizeof(u_int32_t));
 644         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 645                 size += NFA_SPACE(sizeof(u_int32_t));
 646
 647         qthreshold = inst->qthreshold;
 648         /* per-rule qthreshold overrides per-instance */
 649         if (qthreshold > li->u.ulog.qthreshold)
 650                 qthreshold = li->u.ulog.qthreshold;
 651
 652         switch (inst->copy_mode) {
 653         case NFULNL_COPY_META:
 654         case NFULNL_COPY_NONE:
 655                 data_len = 0;
 656                 break;
 657
 658         case NFULNL_COPY_PACKET:
 659                 if (inst->copy_range == 0
 660                     || inst->copy_range > skb->len)
 661                         data_len = skb->len;
 662                 else
 663                         data_len = inst->copy_range;
 664
 665                 size += NFA_SPACE(data_len);
 666                 UDEBUG("copy_packet, therefore size now %u\n", size);
 667                 break;
 668
 669         default:
 670                 spin_unlock_bh(&inst->lock);
 671                 instance_put(inst);
 672                 return;
 673         }
 674
 675         if (size > inst->nlbufsiz)
 676                 nlbufsiz = size;
 677         else
 678                 nlbufsiz = inst->nlbufsiz;
 679
 680         if (!inst->skb) {
 681                 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
 682                         UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
 683                                 inst->nlbufsiz, size);
 684                         goto alloc_failure;
 685                 }
 686         } else if (inst->qlen >= qthreshold ||
 687                    size > skb_tailroom(inst->skb)) {
 688                 /* either the queue len is too high or we don't have
 689                  * enough room in the skb left. flush to userspace. */
 690                 UDEBUG("flushing old skb\n");
 691
 692                 __nfulnl_send(inst);
 693
 694                 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
 695                         UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
 696                                 inst->nlbufsiz, size);
 697                         goto alloc_failure;
 698                 }
 699         }
 700
 701         UDEBUG("qlen %d, qthreshold %d\n", inst->qlen, qthreshold);
 702         inst->qlen++;
 703
 704         __build_packet_message(inst, skb, data_len, pf,
 705                                 hooknum, in, out, li, prefix, plen);
 706
 707         /* timer_pending always called within inst->lock, so there
 708          * is no chance of a race here */
 709         if (!timer_pending(&inst->timer)) {
 710                 instance_get(inst);
 711                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 712                 add_timer(&inst->timer);
 713         }
 714
 715 unlock_and_release:
 716         spin_unlock_bh(&inst->lock);
 717         instance_put(inst);
 718         return;
 719
 720 alloc_failure:
 721         UDEBUG("error allocating skb\n");
 722         /* FIXME: statistics */
 723         goto unlock_and_release;
 724 }
 725
 726 static int
 727 nfulnl_rcv_nl_event(struct notifier_block *this,
 728                    unsigned long event, void *ptr)
 729 {
 730         struct netlink_notify *n = ptr;
 731
 732         if (event == NETLINK_URELEASE &&
 733             n->protocol == NETLINK_NETFILTER && n->pid) {
 734                 int i;
 735
 736                 /* destroy all instances for this pid */
 737                 write_lock_bh(&instances_lock);
 738                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 739                         struct hlist_node *tmp, *t2;
 740                         struct nfulnl_instance *inst;
 741                         struct hlist_head *head = &instance_table[i];
 742
 743                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
 744                                 UDEBUG("node = %p\n", inst);
 745                                 if (n->pid == inst->peer_pid)
 746                                         __instance_destroy(inst);
 747                         }
 748                 }
 749                 write_unlock_bh(&instances_lock);
 750         }
 751         return NOTIFY_DONE;
 752 }
 753
 754 static struct notifier_block nfulnl_rtnl_notifier = {
 755         .notifier_call  = nfulnl_rcv_nl_event,
 756 };
 757
 758 static int
 759 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 760                   struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
 761 {
 762         return -ENOTSUPP;
 763 }
 764
 765 static struct nf_logger nfulnl_logger = {
 766         .name   = "nfnetlink_log",
 767         .logfn  = &nfulnl_log_packet,
 768         .me     = THIS_MODULE,
 769 };
 770
 771 static const int nfula_min[NFULA_MAX] = {
 772         [NFULA_PACKET_HDR-1]    = sizeof(struct nfulnl_msg_packet_hdr),
 773         [NFULA_MARK-1]          = sizeof(u_int32_t),
 774         [NFULA_TIMESTAMP-1]     = sizeof(struct nfulnl_msg_packet_timestamp),
 775         [NFULA_IFINDEX_INDEV-1] = sizeof(u_int32_t),
 776         [NFULA_IFINDEX_OUTDEV-1]= sizeof(u_int32_t),
 777         [NFULA_IFINDEX_PHYSINDEV-1]     = sizeof(u_int32_t),
 778         [NFULA_IFINDEX_PHYSOUTDEV-1]    = sizeof(u_int32_t),
 779         [NFULA_HWADDR-1]        = sizeof(struct nfulnl_msg_packet_hw),
 780         [NFULA_PAYLOAD-1]       = 0,
 781         [NFULA_PREFIX-1]        = 0,
 782         [NFULA_UID-1]           = sizeof(u_int32_t),
 783         [NFULA_SEQ-1]           = sizeof(u_int32_t),
 784         [NFULA_SEQ_GLOBAL-1]    = sizeof(u_int32_t),
 785 };
 786
 787 static const int nfula_cfg_min[NFULA_CFG_MAX] = {
 788         [NFULA_CFG_CMD-1]       = sizeof(struct nfulnl_msg_config_cmd),
 789         [NFULA_CFG_MODE-1]      = sizeof(struct nfulnl_msg_config_mode),
 790         [NFULA_CFG_TIMEOUT-1]   = sizeof(u_int32_t),
 791         [NFULA_CFG_QTHRESH-1]   = sizeof(u_int32_t),
 792         [NFULA_CFG_NLBUFSIZ-1]  = sizeof(u_int32_t),
 793         [NFULA_CFG_FLAGS-1]     = sizeof(u_int16_t),
 794 };
 795
 796 static int
 797 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 798                    struct nlmsghdr *nlh, struct nfattr *nfula[], int *errp)
 799 {
 800         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 801         u_int16_t group_num = ntohs(nfmsg->res_id);
 802         struct nfulnl_instance *inst;
 803         int ret = 0;
 804
 805         UDEBUG("entering for msg %u\n", NFNL_MSG_TYPE(nlh->nlmsg_type));
 806
 807         if (nfattr_bad_size(nfula, NFULA_CFG_MAX, nfula_cfg_min)) {
 808                 UDEBUG("bad attribute size\n");
 809                 return -EINVAL;
 810         }
 811
 812         inst = instance_lookup_get(group_num);
 813         if (nfula[NFULA_CFG_CMD-1]) {
 814                 u_int8_t pf = nfmsg->nfgen_family;
 815                 struct nfulnl_msg_config_cmd *cmd;
 816                 cmd = NFA_DATA(nfula[NFULA_CFG_CMD-1]);
 817                 UDEBUG("found CFG_CMD for\n");
 818
 819                 switch (cmd->command) {
 820                 case NFULNL_CFG_CMD_BIND:
 821                         if (inst) {
 822                                 ret = -EBUSY;
 823                                 goto out_put;
 824                         }
 825
 826                         inst = instance_create(group_num,
 827                                                NETLINK_CB(skb).pid);
 828                         if (!inst) {
 829                                 ret = -EINVAL;
 830                                 goto out_put;
 831                         }
 832                         break;
 833                 case NFULNL_CFG_CMD_UNBIND:
 834                         if (!inst) {
 835                                 ret = -ENODEV;
 836                                 goto out_put;
 837                         }
 838
 839                         if (inst->peer_pid != NETLINK_CB(skb).pid) {
 840                                 ret = -EPERM;
 841                                 goto out_put;
 842                         }
 843
 844                         instance_destroy(inst);
 845                         break;
 846                 case NFULNL_CFG_CMD_PF_BIND:
 847                         UDEBUG("registering log handler for pf=%u\n", pf);
 848                         ret = nf_log_register(pf, &nfulnl_logger);
 849                         break;
 850                 case NFULNL_CFG_CMD_PF_UNBIND:
 851                         UDEBUG("unregistering log handler for pf=%u\n", pf);
 852                         /* This is a bug and a feature.  We cannot unregister
 853                          * other handlers, like nfnetlink_inst can */
 854                         nf_log_unregister_pf(pf);
 855                         break;
 856                 default:
 857                         ret = -EINVAL;
 858                         break;
 859                 }
 860
 861                 if (!inst)
 862                         goto out;
 863         } else {
 864                 if (!inst) {
 865                         UDEBUG("no config command, and no instance for "
 866                                 "group=%u pid=%u =>ENOENT\n",
 867                                 group_num, NETLINK_CB(skb).pid);
 868                         ret = -ENOENT;
 869                         goto out_put;
 870                 }
 871
 872                 if (inst->peer_pid != NETLINK_CB(skb).pid) {
 873                         UDEBUG("no config command, and wrong pid\n");
 874                         ret = -EPERM;
 875                         goto out_put;
 876                 }
 877         }
 878
 879         if (nfula[NFULA_CFG_MODE-1]) {
 880                 struct nfulnl_msg_config_mode *params;
 881                 params = NFA_DATA(nfula[NFULA_CFG_MODE-1]);
 882
 883                 nfulnl_set_mode(inst, params->copy_mode,
 884                                 ntohl(params->copy_range));
 885         }
 886
 887         if (nfula[NFULA_CFG_TIMEOUT-1]) {
 888                 __be32 timeout =
 889                         *(__be32 *)NFA_DATA(nfula[NFULA_CFG_TIMEOUT-1]);
 890
 891                 nfulnl_set_timeout(inst, ntohl(timeout));
 892         }
 893
 894         if (nfula[NFULA_CFG_NLBUFSIZ-1]) {
 895                 __be32 nlbufsiz =
 896                         *(__be32 *)NFA_DATA(nfula[NFULA_CFG_NLBUFSIZ-1]);
 897
 898                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 899         }
 900
 901         if (nfula[NFULA_CFG_QTHRESH-1]) {
 902                 __be32 qthresh =
 903                         *(__be32 *)NFA_DATA(nfula[NFULA_CFG_QTHRESH-1]);
 904
 905                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 906         }
 907
 908         if (nfula[NFULA_CFG_FLAGS-1]) {
 909                 __be16 flags =
 910                         *(__be16 *)NFA_DATA(nfula[NFULA_CFG_FLAGS-1]);
 911                 nfulnl_set_flags(inst, ntohs(flags));
 912         }
 913
 914 out_put:
 915         instance_put(inst);
 916 out:
 917         return ret;
 918 }
 919
 920 static struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 921         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 922                                     .attr_count = NFULA_MAX, },
 923         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 924                                     .attr_count = NFULA_CFG_MAX, },
 925 };
 926
 927 static struct nfnetlink_subsystem nfulnl_subsys = {
 928         .name           = "log",
 929         .subsys_id      = NFNL_SUBSYS_ULOG,
 930         .cb_count       = NFULNL_MSG_MAX,
 931         .cb             = nfulnl_cb,
 932 };
 933
 934 #ifdef CONFIG_PROC_FS
 935 struct iter_state {
 936         unsigned int bucket;
 937 };
 938
 939 static struct hlist_node *get_first(struct seq_file *seq)
 940 {
 941         struct iter_state *st = seq->private;
 942
 943         if (!st)
 944                 return NULL;
 945
 946         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 947                 if (!hlist_empty(&instance_table[st->bucket]))
 948                         return instance_table[st->bucket].first;
 949         }
 950         return NULL;
 951 }
 952
 953 static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
 954 {
 955         struct iter_state *st = seq->private;
 956
 957         h = h->next;
 958         while (!h) {
 959                 if (++st->bucket >= INSTANCE_BUCKETS)
 960                         return NULL;
 961
 962                 h = instance_table[st->bucket].first;
 963         }
 964         return h;
 965 }
 966
 967 static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
 968 {
 969         struct hlist_node *head;
 970         head = get_first(seq);
 971
 972         if (head)
 973                 while (pos && (head = get_next(seq, head)))
 974                         pos--;
 975         return pos ? NULL : head;
 976 }
 977
 978 static void *seq_start(struct seq_file *seq, loff_t *pos)
 979 {
 980         read_lock_bh(&instances_lock);
 981         return get_idx(seq, *pos);
 982 }
 983
 984 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 985 {
 986         (*pos)++;
 987         return get_next(s, v);
 988 }
 989
 990 static void seq_stop(struct seq_file *s, void *v)
 991 {
 992         read_unlock_bh(&instances_lock);
 993 }
 994
 995 static int seq_show(struct seq_file *s, void *v)
 996 {
 997         const struct nfulnl_instance *inst = v;
 998
 999         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
1000                           inst->group_num,
1001                           inst->peer_pid, inst->qlen,
1002                           inst->copy_mode, inst->copy_range,
1003                           inst->flushtimeout, atomic_read(&inst->use));
1004 }
1005
1006 static struct seq_operations nful_seq_ops = {
1007         .start  = seq_start,
1008         .next   = seq_next,
1009         .stop   = seq_stop,
1010         .show   = seq_show,
1011 };
1012
1013 static int nful_open(struct inode *inode, struct file *file)
1014 {
1015         struct seq_file *seq;
1016         struct iter_state *is;
1017         int ret;
1018
1019         is = kzalloc(sizeof(*is), GFP_KERNEL);
1020         if (!is)
1021                 return -ENOMEM;
1022         ret = seq_open(file, &nful_seq_ops);
1023         if (ret < 0)
1024                 goto out_free;
1025         seq = file->private_data;
1026         seq->private = is;
1027         return ret;
1028 out_free:
1029         kfree(is);
1030         return ret;
1031 }
1032
1033 static const struct file_operations nful_file_ops = {
1034         .owner   = THIS_MODULE,
1035         .open    = nful_open,
1036         .read    = seq_read,
1037         .llseek  = seq_lseek,
1038         .release = seq_release_private,
1039 };
1040
1041 #endif /* PROC_FS */
1042
1043 static int __init nfnetlink_log_init(void)
1044 {
1045         int i, status = -ENOMEM;
1046 #ifdef CONFIG_PROC_FS
1047         struct proc_dir_entry *proc_nful;
1048 #endif
1049
1050         for (i = 0; i < INSTANCE_BUCKETS; i++)
1051                 INIT_HLIST_HEAD(&instance_table[i]);
1052
1053         /* it's not really all that important to have a random value, so
1054          * we can do this from the init function, even if there hasn't
1055          * been that much entropy yet */
1056         get_random_bytes(&hash_init, sizeof(hash_init));
1057
1058         netlink_register_notifier(&nfulnl_rtnl_notifier);
1059         status = nfnetlink_subsys_register(&nfulnl_subsys);
1060         if (status < 0) {
1061                 printk(KERN_ERR "log: failed to create netlink socket\n");
1062                 goto cleanup_netlink_notifier;
1063         }
1064
1065 #ifdef CONFIG_PROC_FS
1066         proc_nful = create_proc_entry("nfnetlink_log", 0440,
1067                                       proc_net_netfilter);
1068         if (!proc_nful)
1069                 goto cleanup_subsys;
1070         proc_nful->proc_fops = &nful_file_ops;
1071 #endif
1072         return status;
1073
1074 #ifdef CONFIG_PROC_FS
1075 cleanup_subsys:
1076         nfnetlink_subsys_unregister(&nfulnl_subsys);
1077 #endif
1078 cleanup_netlink_notifier:
1079         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1080         return status;
1081 }
1082
1083 static void __exit nfnetlink_log_fini(void)
1084 {
1085         nf_log_unregister(&nfulnl_logger);
1086 #ifdef CONFIG_PROC_FS
1087         remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1088 #endif
1089         nfnetlink_subsys_unregister(&nfulnl_subsys);
1090         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1091 }
1092
1093 MODULE_DESCRIPTION("netfilter userspace logging");
1094 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1095 MODULE_LICENSE("GPL");
1096 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1097
1098 module_init(nfnetlink_log_init);
1099 module_exit(nfnetlink_log_fini);