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 <linux/slab.h>
  32 #include <net/sock.h>
  33 #include <net/netfilter/nf_log.h>
  34 #include <net/netfilter/nfnetlink_log.h>
  35
  36 #include <linux/atomic.h>
  37
  38 #ifdef CONFIG_BRIDGE_NETFILTER
  39 #include "../bridge/br_private.h"
  40 #endif
  41
  42 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  43 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  44 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  45 #define NFULNL_COPY_RANGE_MAX   0xFFFF  /* max packet size is limited by 16-bit struct nfattr nfa_len field */
  46
  47 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
  48                                      printk(x, ## args); } while (0);
  49
  50 struct nfulnl_instance {
  51         struct hlist_node hlist;        /* global list of instances */
  52         spinlock_t lock;
  53         atomic_t use;                   /* use count */
  54
  55         unsigned int qlen;              /* number of nlmsgs in skb */
  56         struct sk_buff *skb;            /* pre-allocatd skb */
  57         struct timer_list timer;
  58         int peer_pid;                   /* PID of the peer process */
  59
  60         /* configurable parameters */
  61         unsigned int flushtimeout;      /* timeout until queue flush */
  62         unsigned int nlbufsiz;          /* netlink buffer allocation size */
  63         unsigned int qthreshold;        /* threshold of the queue */
  64         u_int32_t copy_range;
  65         u_int32_t seq;                  /* instance-local sequential counter */
  66         u_int16_t group_num;            /* number of this queue */
  67         u_int16_t flags;
  68         u_int8_t copy_mode;
  69         struct rcu_head rcu;
  70 };
  71
  72 static DEFINE_SPINLOCK(instances_lock);
  73 static atomic_t global_seq;
  74
  75 #define INSTANCE_BUCKETS        16
  76 static struct hlist_head instance_table[INSTANCE_BUCKETS];
  77 static unsigned int hash_init;
  78
  79 static inline u_int8_t instance_hashfn(u_int16_t group_num)
  80 {
  81         return ((group_num & 0xff) % INSTANCE_BUCKETS);
  82 }
  83
  84 static struct nfulnl_instance *
  85 __instance_lookup(u_int16_t group_num)
  86 {
  87         struct hlist_head *head;
  88         struct hlist_node *pos;
  89         struct nfulnl_instance *inst;
  90
  91         head = &instance_table[instance_hashfn(group_num)];
  92         hlist_for_each_entry_rcu(inst, pos, head, hlist) {
  93                 if (inst->group_num == group_num)
  94                         return inst;
  95         }
  96         return NULL;
  97 }
  98
  99 static inline void
 100 instance_get(struct nfulnl_instance *inst)
 101 {
 102         atomic_inc(&inst->use);
 103 }
 104
 105 static struct nfulnl_instance *
 106 instance_lookup_get(u_int16_t group_num)
 107 {
 108         struct nfulnl_instance *inst;
 109
 110         rcu_read_lock_bh();
 111         inst = __instance_lookup(group_num);
 112         if (inst && !atomic_inc_not_zero(&inst->use))
 113                 inst = NULL;
 114         rcu_read_unlock_bh();
 115
 116         return inst;
 117 }
 118
 119 static void nfulnl_instance_free_rcu(struct rcu_head *head)
 120 {
 121         kfree(container_of(head, struct nfulnl_instance, rcu));
 122         module_put(THIS_MODULE);
 123 }
 124
 125 static void
 126 instance_put(struct nfulnl_instance *inst)
 127 {
 128         if (inst && atomic_dec_and_test(&inst->use))
 129                 call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
 130 }
 131
 132 static void nfulnl_timer(unsigned long data);
 133
 134 static struct nfulnl_instance *
 135 instance_create(u_int16_t group_num, int pid)
 136 {
 137         struct nfulnl_instance *inst;
 138         int err;
 139
 140         spin_lock_bh(&instances_lock);
 141         if (__instance_lookup(group_num)) {
 142                 err = -EEXIST;
 143                 goto out_unlock;
 144         }
 145
 146         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 147         if (!inst) {
 148                 err = -ENOMEM;
 149                 goto out_unlock;
 150         }
 151
 152         if (!try_module_get(THIS_MODULE)) {
 153                 kfree(inst);
 154                 err = -EAGAIN;
 155                 goto out_unlock;
 156         }
 157
 158         INIT_HLIST_NODE(&inst->hlist);
 159         spin_lock_init(&inst->lock);
 160         /* needs to be two, since we _put() after creation */
 161         atomic_set(&inst->use, 2);
 162
 163         setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
 164
 165         inst->peer_pid = pid;
 166         inst->group_num = group_num;
 167
 168         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 169         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 170         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 171         inst->copy_mode         = NFULNL_COPY_PACKET;
 172         inst->copy_range        = NFULNL_COPY_RANGE_MAX;
 173
 174         hlist_add_head_rcu(&inst->hlist,
 175                        &instance_table[instance_hashfn(group_num)]);
 176
 177         spin_unlock_bh(&instances_lock);
 178
 179         return inst;
 180
 181 out_unlock:
 182         spin_unlock_bh(&instances_lock);
 183         return ERR_PTR(err);
 184 }
 185
 186 static void __nfulnl_flush(struct nfulnl_instance *inst);
 187
 188 /* called with BH disabled */
 189 static void
 190 __instance_destroy(struct nfulnl_instance *inst)
 191 {
 192         /* first pull it out of the global list */
 193         hlist_del_rcu(&inst->hlist);
 194
 195         /* then flush all pending packets from skb */
 196
 197         spin_lock(&inst->lock);
 198
 199         /* lockless readers wont be able to use us */
 200         inst->copy_mode = NFULNL_COPY_DISABLED;
 201
 202         if (inst->skb)
 203                 __nfulnl_flush(inst);
 204         spin_unlock(&inst->lock);
 205
 206         /* and finally put the refcount */
 207         instance_put(inst);
 208 }
 209
 210 static inline void
 211 instance_destroy(struct nfulnl_instance *inst)
 212 {
 213         spin_lock_bh(&instances_lock);
 214         __instance_destroy(inst);
 215         spin_unlock_bh(&instances_lock);
 216 }
 217
 218 static int
 219 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 220                   unsigned int range)
 221 {
 222         int status = 0;
 223
 224         spin_lock_bh(&inst->lock);
 225
 226         switch (mode) {
 227         case NFULNL_COPY_NONE:
 228         case NFULNL_COPY_META:
 229                 inst->copy_mode = mode;
 230                 inst->copy_range = 0;
 231                 break;
 232
 233         case NFULNL_COPY_PACKET:
 234                 inst->copy_mode = mode;
 235                 inst->copy_range = min_t(unsigned int,
 236                                          range, NFULNL_COPY_RANGE_MAX);
 237                 break;
 238
 239         default:
 240                 status = -EINVAL;
 241                 break;
 242         }
 243
 244         spin_unlock_bh(&inst->lock);
 245
 246         return status;
 247 }
 248
 249 static int
 250 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 251 {
 252         int status;
 253
 254         spin_lock_bh(&inst->lock);
 255         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 256                 status = -ERANGE;
 257         else if (nlbufsiz > 131072)
 258                 status = -ERANGE;
 259         else {
 260                 inst->nlbufsiz = nlbufsiz;
 261                 status = 0;
 262         }
 263         spin_unlock_bh(&inst->lock);
 264
 265         return status;
 266 }
 267
 268 static int
 269 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 270 {
 271         spin_lock_bh(&inst->lock);
 272         inst->flushtimeout = timeout;
 273         spin_unlock_bh(&inst->lock);
 274
 275         return 0;
 276 }
 277
 278 static int
 279 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 280 {
 281         spin_lock_bh(&inst->lock);
 282         inst->qthreshold = qthresh;
 283         spin_unlock_bh(&inst->lock);
 284
 285         return 0;
 286 }
 287
 288 static int
 289 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 290 {
 291         spin_lock_bh(&inst->lock);
 292         inst->flags = flags;
 293         spin_unlock_bh(&inst->lock);
 294
 295         return 0;
 296 }
 297
 298 static struct sk_buff *
 299 nfulnl_alloc_skb(unsigned int inst_size, unsigned int pkt_size)
 300 {
 301         struct sk_buff *skb;
 302         unsigned int n;
 303
 304         /* alloc skb which should be big enough for a whole multipart
 305          * message.  WARNING: has to be <= 128k due to slab restrictions */
 306
 307         n = max(inst_size, pkt_size);
 308         skb = alloc_skb(n, GFP_ATOMIC);
 309         if (!skb) {
 310                 pr_notice("nfnetlink_log: can't alloc whole buffer (%u bytes)\n",
 311                         inst_size);
 312
 313                 if (n > pkt_size) {
 314                         /* try to allocate only as much as we need for current
 315                          * packet */
 316
 317                         skb = alloc_skb(pkt_size, GFP_ATOMIC);
 318                         if (!skb)
 319                                 pr_err("nfnetlink_log: can't even alloc %u "
 320                                        "bytes\n", pkt_size);
 321                 }
 322         }
 323
 324         return skb;
 325 }
 326
 327 static int
 328 __nfulnl_send(struct nfulnl_instance *inst)
 329 {
 330         int status = -1;
 331
 332         if (inst->qlen > 1)
 333                 NLMSG_PUT(inst->skb, 0, 0,
 334                           NLMSG_DONE,
 335                           sizeof(struct nfgenmsg));
 336
 337         status = nfnetlink_unicast(inst->skb, &init_net, inst->peer_pid,
 338                                    MSG_DONTWAIT);
 339
 340         inst->qlen = 0;
 341         inst->skb = NULL;
 342
 343 nlmsg_failure:
 344         return status;
 345 }
 346
 347 static void
 348 __nfulnl_flush(struct nfulnl_instance *inst)
 349 {
 350         /* timer holds a reference */
 351         if (del_timer(&inst->timer))
 352                 instance_put(inst);
 353         if (inst->skb)
 354                 __nfulnl_send(inst);
 355 }
 356
 357 static void
 358 nfulnl_timer(unsigned long data)
 359 {
 360         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 361
 362         spin_lock_bh(&inst->lock);
 363         if (inst->skb)
 364                 __nfulnl_send(inst);
 365         spin_unlock_bh(&inst->lock);
 366         instance_put(inst);
 367 }
 368
 369 /* This is an inline function, we don't really care about a long
 370  * list of arguments */
 371 static inline int
 372 __build_packet_message(struct nfulnl_instance *inst,
 373                         const struct sk_buff *skb,
 374                         unsigned int data_len,
 375                         u_int8_t pf,
 376                         unsigned int hooknum,
 377                         const struct net_device *indev,
 378                         const struct net_device *outdev,
 379                         const char *prefix, unsigned int plen)
 380 {
 381         struct nfulnl_msg_packet_hdr pmsg;
 382         struct nlmsghdr *nlh;
 383         struct nfgenmsg *nfmsg;
 384         sk_buff_data_t old_tail = inst->skb->tail;
 385
 386         nlh = NLMSG_PUT(inst->skb, 0, 0,
 387                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 388                         sizeof(struct nfgenmsg));
 389         nfmsg = NLMSG_DATA(nlh);
 390         nfmsg->nfgen_family = pf;
 391         nfmsg->version = NFNETLINK_V0;
 392         nfmsg->res_id = htons(inst->group_num);
 393
 394         pmsg.hw_protocol        = skb->protocol;
 395         pmsg.hook               = hooknum;
 396
 397         NLA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
 398
 399         if (prefix)
 400                 NLA_PUT(inst->skb, NFULA_PREFIX, plen, prefix);
 401
 402         if (indev) {
 403 #ifndef CONFIG_BRIDGE_NETFILTER
 404                 NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_INDEV,
 405                              htonl(indev->ifindex));
 406 #else
 407                 if (pf == PF_BRIDGE) {
 408                         /* Case 1: outdev is physical input device, we need to
 409                          * look for bridge group (when called from
 410                          * netfilter_bridge) */
 411                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 412                                      htonl(indev->ifindex));
 413                         /* this is the bridge group "brX" */
 414                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 415                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_INDEV,
 416                                      htonl(br_port_get_rcu(indev)->br->dev->ifindex));
 417                 } else {
 418                         /* Case 2: indev is bridge group, we need to look for
 419                          * physical device (when called from ipv4) */
 420                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_INDEV,
 421                                      htonl(indev->ifindex));
 422                         if (skb->nf_bridge && skb->nf_bridge->physindev)
 423                                 NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 424                                              htonl(skb->nf_bridge->physindev->ifindex));
 425                 }
 426 #endif
 427         }
 428
 429         if (outdev) {
 430 #ifndef CONFIG_BRIDGE_NETFILTER
 431                 NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_OUTDEV,
 432                              htonl(outdev->ifindex));
 433 #else
 434                 if (pf == PF_BRIDGE) {
 435                         /* Case 1: outdev is physical output device, we need to
 436                          * look for bridge group (when called from
 437                          * netfilter_bridge) */
 438                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 439                                      htonl(outdev->ifindex));
 440                         /* this is the bridge group "brX" */
 441                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 442                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_OUTDEV,
 443                                      htonl(br_port_get_rcu(outdev)->br->dev->ifindex));
 444                 } else {
 445                         /* Case 2: indev is a bridge group, we need to look
 446                          * for physical device (when called from ipv4) */
 447                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_OUTDEV,
 448                                      htonl(outdev->ifindex));
 449                         if (skb->nf_bridge && skb->nf_bridge->physoutdev)
 450                                 NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 451                                              htonl(skb->nf_bridge->physoutdev->ifindex));
 452                 }
 453 #endif
 454         }
 455
 456         if (skb->mark)
 457                 NLA_PUT_BE32(inst->skb, NFULA_MARK, htonl(skb->mark));
 458
 459         if (indev && skb->dev &&
 460             skb->mac_header != skb->network_header) {
 461                 struct nfulnl_msg_packet_hw phw;
 462                 int len = dev_parse_header(skb, phw.hw_addr);
 463                 if (len > 0) {
 464                         phw.hw_addrlen = htons(len);
 465                         NLA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
 466                 }
 467         }
 468
 469         if (indev && skb_mac_header_was_set(skb)) {
 470                 NLA_PUT_BE16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type));
 471                 NLA_PUT_BE16(inst->skb, NFULA_HWLEN,
 472                              htons(skb->dev->hard_header_len));
 473                 NLA_PUT(inst->skb, NFULA_HWHEADER, skb->dev->hard_header_len,
 474                         skb_mac_header(skb));
 475         }
 476
 477         if (skb->tstamp.tv64) {
 478                 struct nfulnl_msg_packet_timestamp ts;
 479                 struct timeval tv = ktime_to_timeval(skb->tstamp);
 480                 ts.sec = cpu_to_be64(tv.tv_sec);
 481                 ts.usec = cpu_to_be64(tv.tv_usec);
 482
 483                 NLA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
 484         }
 485
 486         /* UID */
 487         if (skb->sk) {
 488                 read_lock_bh(&skb->sk->sk_callback_lock);
 489                 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
 490                         struct file *file = skb->sk->sk_socket->file;
 491                         __be32 uid = htonl(file->f_cred->fsuid);
 492                         __be32 gid = htonl(file->f_cred->fsgid);
 493                         /* need to unlock here since NLA_PUT may goto */
 494                         read_unlock_bh(&skb->sk->sk_callback_lock);
 495                         NLA_PUT_BE32(inst->skb, NFULA_UID, uid);
 496                         NLA_PUT_BE32(inst->skb, NFULA_GID, gid);
 497                 } else
 498                         read_unlock_bh(&skb->sk->sk_callback_lock);
 499         }
 500
 501         /* local sequence number */
 502         if (inst->flags & NFULNL_CFG_F_SEQ)
 503                 NLA_PUT_BE32(inst->skb, NFULA_SEQ, htonl(inst->seq++));
 504
 505         /* global sequence number */
 506         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 507                 NLA_PUT_BE32(inst->skb, NFULA_SEQ_GLOBAL,
 508                              htonl(atomic_inc_return(&global_seq)));
 509
 510         if (data_len) {
 511                 struct nlattr *nla;
 512                 int size = nla_attr_size(data_len);
 513
 514                 if (skb_tailroom(inst->skb) < nla_total_size(data_len)) {
 515                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
 516                         goto nlmsg_failure;
 517                 }
 518
 519                 nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
 520                 nla->nla_type = NFULA_PAYLOAD;
 521                 nla->nla_len = size;
 522
 523                 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 524                         BUG();
 525         }
 526
 527         nlh->nlmsg_len = inst->skb->tail - old_tail;
 528         return 0;
 529
 530 nlmsg_failure:
 531 nla_put_failure:
 532         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 533         return -1;
 534 }
 535
 536 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 537
 538 static struct nf_loginfo default_loginfo = {
 539         .type =         NF_LOG_TYPE_ULOG,
 540         .u = {
 541                 .ulog = {
 542                         .copy_len       = 0xffff,
 543                         .group          = 0,
 544                         .qthreshold     = 1,
 545                 },
 546         },
 547 };
 548
 549 /* log handler for internal netfilter logging api */
 550 void
 551 nfulnl_log_packet(u_int8_t pf,
 552                   unsigned int hooknum,
 553                   const struct sk_buff *skb,
 554                   const struct net_device *in,
 555                   const struct net_device *out,
 556                   const struct nf_loginfo *li_user,
 557                   const char *prefix)
 558 {
 559         unsigned int size, data_len;
 560         struct nfulnl_instance *inst;
 561         const struct nf_loginfo *li;
 562         unsigned int qthreshold;
 563         unsigned int plen;
 564
 565         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 566                 li = li_user;
 567         else
 568                 li = &default_loginfo;
 569
 570         inst = instance_lookup_get(li->u.ulog.group);
 571         if (!inst)
 572                 return;
 573
 574         plen = 0;
 575         if (prefix)
 576                 plen = strlen(prefix) + 1;
 577
 578         /* FIXME: do we want to make the size calculation conditional based on
 579          * what is actually present?  way more branches and checks, but more
 580          * memory efficient... */
 581         size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
 582                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 583                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 584                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 585 #ifdef CONFIG_BRIDGE_NETFILTER
 586                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 587                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 588 #endif
 589                 + nla_total_size(sizeof(u_int32_t))     /* mark */
 590                 + nla_total_size(sizeof(u_int32_t))     /* uid */
 591                 + nla_total_size(sizeof(u_int32_t))     /* gid */
 592                 + nla_total_size(plen)                  /* prefix */
 593                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 594                 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp));
 595
 596         if (in && skb_mac_header_was_set(skb)) {
 597                 size +=   nla_total_size(skb->dev->hard_header_len)
 598                         + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 599                         + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 600         }
 601
 602         spin_lock_bh(&inst->lock);
 603
 604         if (inst->flags & NFULNL_CFG_F_SEQ)
 605                 size += nla_total_size(sizeof(u_int32_t));
 606         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 607                 size += nla_total_size(sizeof(u_int32_t));
 608
 609         qthreshold = inst->qthreshold;
 610         /* per-rule qthreshold overrides per-instance */
 611         if (li->u.ulog.qthreshold)
 612                 if (qthreshold > li->u.ulog.qthreshold)
 613                         qthreshold = li->u.ulog.qthreshold;
 614
 615
 616         switch (inst->copy_mode) {
 617         case NFULNL_COPY_META:
 618         case NFULNL_COPY_NONE:
 619                 data_len = 0;
 620                 break;
 621
 622         case NFULNL_COPY_PACKET:
 623                 if (inst->copy_range == 0
 624                     || inst->copy_range > skb->len)
 625                         data_len = skb->len;
 626                 else
 627                         data_len = inst->copy_range;
 628
 629                 size += nla_total_size(data_len);
 630                 break;
 631
 632         case NFULNL_COPY_DISABLED:
 633         default:
 634                 goto unlock_and_release;
 635         }
 636
 637         if (inst->skb &&
 638             size > skb_tailroom(inst->skb) - sizeof(struct nfgenmsg)) {
 639                 /* either the queue len is too high or we don't have
 640                  * enough room in the skb left. flush to userspace. */
 641                 __nfulnl_flush(inst);
 642         }
 643
 644         if (!inst->skb) {
 645                 inst->skb = nfulnl_alloc_skb(inst->nlbufsiz, size);
 646                 if (!inst->skb)
 647                         goto alloc_failure;
 648         }
 649
 650         inst->qlen++;
 651
 652         __build_packet_message(inst, skb, data_len, pf,
 653                                 hooknum, in, out, prefix, plen);
 654
 655         if (inst->qlen >= qthreshold)
 656                 __nfulnl_flush(inst);
 657         /* timer_pending always called within inst->lock, so there
 658          * is no chance of a race here */
 659         else if (!timer_pending(&inst->timer)) {
 660                 instance_get(inst);
 661                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 662                 add_timer(&inst->timer);
 663         }
 664
 665 unlock_and_release:
 666         spin_unlock_bh(&inst->lock);
 667         instance_put(inst);
 668         return;
 669
 670 alloc_failure:
 671         /* FIXME: statistics */
 672         goto unlock_and_release;
 673 }
 674 EXPORT_SYMBOL_GPL(nfulnl_log_packet);
 675
 676 static int
 677 nfulnl_rcv_nl_event(struct notifier_block *this,
 678                    unsigned long event, void *ptr)
 679 {
 680         struct netlink_notify *n = ptr;
 681
 682         if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 683                 int i;
 684
 685                 /* destroy all instances for this pid */
 686                 spin_lock_bh(&instances_lock);
 687                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 688                         struct hlist_node *tmp, *t2;
 689                         struct nfulnl_instance *inst;
 690                         struct hlist_head *head = &instance_table[i];
 691
 692                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
 693                                 if ((net_eq(n->net, &init_net)) &&
 694                                     (n->pid == inst->peer_pid))
 695                                         __instance_destroy(inst);
 696                         }
 697                 }
 698                 spin_unlock_bh(&instances_lock);
 699         }
 700         return NOTIFY_DONE;
 701 }
 702
 703 static struct notifier_block nfulnl_rtnl_notifier = {
 704         .notifier_call  = nfulnl_rcv_nl_event,
 705 };
 706
 707 static int
 708 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 709                    const struct nlmsghdr *nlh,
 710                    const struct nlattr * const nfqa[])
 711 {
 712         return -ENOTSUPP;
 713 }
 714
 715 static struct nf_logger nfulnl_logger __read_mostly = {
 716         .name   = "nfnetlink_log",
 717         .logfn  = &nfulnl_log_packet,
 718         .me     = THIS_MODULE,
 719 };
 720
 721 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 722         [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 723         [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 724         [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 725         [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 726         [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 727         [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 728 };
 729
 730 static int
 731 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 732                    const struct nlmsghdr *nlh,
 733                    const struct nlattr * const nfula[])
 734 {
 735         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 736         u_int16_t group_num = ntohs(nfmsg->res_id);
 737         struct nfulnl_instance *inst;
 738         struct nfulnl_msg_config_cmd *cmd = NULL;
 739         int ret = 0;
 740
 741         if (nfula[NFULA_CFG_CMD]) {
 742                 u_int8_t pf = nfmsg->nfgen_family;
 743                 cmd = nla_data(nfula[NFULA_CFG_CMD]);
 744
 745                 /* Commands without queue context */
 746                 switch (cmd->command) {
 747                 case NFULNL_CFG_CMD_PF_BIND:
 748                         return nf_log_bind_pf(pf, &nfulnl_logger);
 749                 case NFULNL_CFG_CMD_PF_UNBIND:
 750                         nf_log_unbind_pf(pf);
 751                         return 0;
 752                 }
 753         }
 754
 755         inst = instance_lookup_get(group_num);
 756         if (inst && inst->peer_pid != NETLINK_CB(skb).pid) {
 757                 ret = -EPERM;
 758                 goto out_put;
 759         }
 760
 761         if (cmd != NULL) {
 762                 switch (cmd->command) {
 763                 case NFULNL_CFG_CMD_BIND:
 764                         if (inst) {
 765                                 ret = -EBUSY;
 766                                 goto out_put;
 767                         }
 768
 769                         inst = instance_create(group_num,
 770                                                NETLINK_CB(skb).pid);
 771                         if (IS_ERR(inst)) {
 772                                 ret = PTR_ERR(inst);
 773                                 goto out;
 774                         }
 775                         break;
 776                 case NFULNL_CFG_CMD_UNBIND:
 777                         if (!inst) {
 778                                 ret = -ENODEV;
 779                                 goto out;
 780                         }
 781
 782                         instance_destroy(inst);
 783                         goto out_put;
 784                 default:
 785                         ret = -ENOTSUPP;
 786                         break;
 787                 }
 788         }
 789
 790         if (nfula[NFULA_CFG_MODE]) {
 791                 struct nfulnl_msg_config_mode *params;
 792                 params = nla_data(nfula[NFULA_CFG_MODE]);
 793
 794                 if (!inst) {
 795                         ret = -ENODEV;
 796                         goto out;
 797                 }
 798                 nfulnl_set_mode(inst, params->copy_mode,
 799                                 ntohl(params->copy_range));
 800         }
 801
 802         if (nfula[NFULA_CFG_TIMEOUT]) {
 803                 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 804
 805                 if (!inst) {
 806                         ret = -ENODEV;
 807                         goto out;
 808                 }
 809                 nfulnl_set_timeout(inst, ntohl(timeout));
 810         }
 811
 812         if (nfula[NFULA_CFG_NLBUFSIZ]) {
 813                 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 814
 815                 if (!inst) {
 816                         ret = -ENODEV;
 817                         goto out;
 818                 }
 819                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 820         }
 821
 822         if (nfula[NFULA_CFG_QTHRESH]) {
 823                 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 824
 825                 if (!inst) {
 826                         ret = -ENODEV;
 827                         goto out;
 828                 }
 829                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 830         }
 831
 832         if (nfula[NFULA_CFG_FLAGS]) {
 833                 __be16 flags = nla_get_be16(nfula[NFULA_CFG_FLAGS]);
 834
 835                 if (!inst) {
 836                         ret = -ENODEV;
 837                         goto out;
 838                 }
 839                 nfulnl_set_flags(inst, ntohs(flags));
 840         }
 841
 842 out_put:
 843         instance_put(inst);
 844 out:
 845         return ret;
 846 }
 847
 848 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 849         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 850                                     .attr_count = NFULA_MAX, },
 851         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 852                                     .attr_count = NFULA_CFG_MAX,
 853                                     .policy = nfula_cfg_policy },
 854 };
 855
 856 static const struct nfnetlink_subsystem nfulnl_subsys = {
 857         .name           = "log",
 858         .subsys_id      = NFNL_SUBSYS_ULOG,
 859         .cb_count       = NFULNL_MSG_MAX,
 860         .cb             = nfulnl_cb,
 861 };
 862
 863 #ifdef CONFIG_PROC_FS
 864 struct iter_state {
 865         unsigned int bucket;
 866 };
 867
 868 static struct hlist_node *get_first(struct iter_state *st)
 869 {
 870         if (!st)
 871                 return NULL;
 872
 873         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 874                 if (!hlist_empty(&instance_table[st->bucket]))
 875                         return rcu_dereference_bh(hlist_first_rcu(&instance_table[st->bucket]));
 876         }
 877         return NULL;
 878 }
 879
 880 static struct hlist_node *get_next(struct iter_state *st, struct hlist_node *h)
 881 {
 882         h = rcu_dereference_bh(hlist_next_rcu(h));
 883         while (!h) {
 884                 if (++st->bucket >= INSTANCE_BUCKETS)
 885                         return NULL;
 886
 887                 h = rcu_dereference_bh(hlist_first_rcu(&instance_table[st->bucket]));
 888         }
 889         return h;
 890 }
 891
 892 static struct hlist_node *get_idx(struct iter_state *st, loff_t pos)
 893 {
 894         struct hlist_node *head;
 895         head = get_first(st);
 896
 897         if (head)
 898                 while (pos && (head = get_next(st, head)))
 899                         pos--;
 900         return pos ? NULL : head;
 901 }
 902
 903 static void *seq_start(struct seq_file *seq, loff_t *pos)
 904         __acquires(rcu_bh)
 905 {
 906         rcu_read_lock_bh();
 907         return get_idx(seq->private, *pos);
 908 }
 909
 910 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 911 {
 912         (*pos)++;
 913         return get_next(s->private, v);
 914 }
 915
 916 static void seq_stop(struct seq_file *s, void *v)
 917         __releases(rcu_bh)
 918 {
 919         rcu_read_unlock_bh();
 920 }
 921
 922 static int seq_show(struct seq_file *s, void *v)
 923 {
 924         const struct nfulnl_instance *inst = v;
 925
 926         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
 927                           inst->group_num,
 928                           inst->peer_pid, inst->qlen,
 929                           inst->copy_mode, inst->copy_range,
 930                           inst->flushtimeout, atomic_read(&inst->use));
 931 }
 932
 933 static const struct seq_operations nful_seq_ops = {
 934         .start  = seq_start,
 935         .next   = seq_next,
 936         .stop   = seq_stop,
 937         .show   = seq_show,
 938 };
 939
 940 static int nful_open(struct inode *inode, struct file *file)
 941 {
 942         return seq_open_private(file, &nful_seq_ops,
 943                         sizeof(struct iter_state));
 944 }
 945
 946 static const struct file_operations nful_file_ops = {
 947         .owner   = THIS_MODULE,
 948         .open    = nful_open,
 949         .read    = seq_read,
 950         .llseek  = seq_lseek,
 951         .release = seq_release_private,
 952 };
 953
 954 #endif /* PROC_FS */
 955
 956 static int __init nfnetlink_log_init(void)
 957 {
 958         int i, status = -ENOMEM;
 959
 960         for (i = 0; i < INSTANCE_BUCKETS; i++)
 961                 INIT_HLIST_HEAD(&instance_table[i]);
 962
 963         /* it's not really all that important to have a random value, so
 964          * we can do this from the init function, even if there hasn't
 965          * been that much entropy yet */
 966         get_random_bytes(&hash_init, sizeof(hash_init));
 967
 968         netlink_register_notifier(&nfulnl_rtnl_notifier);
 969         status = nfnetlink_subsys_register(&nfulnl_subsys);
 970         if (status < 0) {
 971                 printk(KERN_ERR "log: failed to create netlink socket\n");
 972                 goto cleanup_netlink_notifier;
 973         }
 974
 975         status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
 976         if (status < 0) {
 977                 printk(KERN_ERR "log: failed to register logger\n");
 978                 goto cleanup_subsys;
 979         }
 980
 981 #ifdef CONFIG_PROC_FS
 982         if (!proc_create("nfnetlink_log", 0440,
 983                          proc_net_netfilter, &nful_file_ops))
 984                 goto cleanup_logger;
 985 #endif
 986         return status;
 987
 988 #ifdef CONFIG_PROC_FS
 989 cleanup_logger:
 990         nf_log_unregister(&nfulnl_logger);
 991 #endif
 992 cleanup_subsys:
 993         nfnetlink_subsys_unregister(&nfulnl_subsys);
 994 cleanup_netlink_notifier:
 995         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
 996         return status;
 997 }
 998
 999 static void __exit nfnetlink_log_fini(void)
1000 {
1001         nf_log_unregister(&nfulnl_logger);
1002 #ifdef CONFIG_PROC_FS
1003         remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1004 #endif
1005         nfnetlink_subsys_unregister(&nfulnl_subsys);
1006         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1007 }
1008
1009 MODULE_DESCRIPTION("netfilter userspace logging");
1010 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1011 MODULE_LICENSE("GPL");
1012 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1013
1014 module_init(nfnetlink_log_init);
1015 module_exit(nfnetlink_log_fini);