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