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