linux/net/netfilter/nfnetlink_log.c
<<
>>
Prefs
   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
  50struct 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
  72static DEFINE_SPINLOCK(instances_lock);
  73static atomic_t global_seq;
  74
  75#define INSTANCE_BUCKETS        16
  76static struct hlist_head instance_table[INSTANCE_BUCKETS];
  77static unsigned int hash_init;
  78
  79static inline u_int8_t instance_hashfn(u_int16_t group_num)
  80{
  81        return ((group_num & 0xff) % INSTANCE_BUCKETS);
  82}
  83
  84static 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
  99static inline void
 100instance_get(struct nfulnl_instance *inst)
 101{
 102        atomic_inc(&inst->use);
 103}
 104
 105static struct nfulnl_instance *
 106instance_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
 119static 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
 125static void
 126instance_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
 132static void nfulnl_timer(unsigned long data);
 133
 134static struct nfulnl_instance *
 135instance_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
 181out_unlock:
 182        spin_unlock_bh(&instances_lock);
 183        return ERR_PTR(err);
 184}
 185
 186static void __nfulnl_flush(struct nfulnl_instance *inst);
 187
 188/* called with BH disabled */
 189static 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
 210static inline void
 211instance_destroy(struct nfulnl_instance *inst)
 212{
 213        spin_lock_bh(&instances_lock);
 214        __instance_destroy(inst);
 215        spin_unlock_bh(&instances_lock);
 216}
 217
 218static int
 219nfulnl_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
 249static int
 250nfulnl_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
 268static int
 269nfulnl_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
 278static int
 279nfulnl_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
 288static int
 289nfulnl_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
 298static struct sk_buff *
 299nfulnl_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                if (n > pkt_size) {
 311                        /* try to allocate only as much as we need for current
 312                         * packet */
 313
 314                        skb = alloc_skb(pkt_size, GFP_ATOMIC);
 315                        if (!skb)
 316                                pr_err("nfnetlink_log: can't even alloc %u bytes\n",
 317                                       pkt_size);
 318                }
 319        }
 320
 321        return skb;
 322}
 323
 324static int
 325__nfulnl_send(struct nfulnl_instance *inst)
 326{
 327        int status = -1;
 328
 329        if (inst->qlen > 1) {
 330                struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
 331                                                 NLMSG_DONE,
 332                                                 sizeof(struct nfgenmsg),
 333                                                 0);
 334                if (!nlh)
 335                        goto out;
 336        }
 337        status = nfnetlink_unicast(inst->skb, &init_net, inst->peer_pid,
 338                                   MSG_DONTWAIT);
 339
 340        inst->qlen = 0;
 341        inst->skb = NULL;
 342out:
 343        return status;
 344}
 345
 346static void
 347__nfulnl_flush(struct nfulnl_instance *inst)
 348{
 349        /* timer holds a reference */
 350        if (del_timer(&inst->timer))
 351                instance_put(inst);
 352        if (inst->skb)
 353                __nfulnl_send(inst);
 354}
 355
 356static void
 357nfulnl_timer(unsigned long data)
 358{
 359        struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 360
 361        spin_lock_bh(&inst->lock);
 362        if (inst->skb)
 363                __nfulnl_send(inst);
 364        spin_unlock_bh(&inst->lock);
 365        instance_put(inst);
 366}
 367
 368/* This is an inline function, we don't really care about a long
 369 * list of arguments */
 370static inline int
 371__build_packet_message(struct nfulnl_instance *inst,
 372                        const struct sk_buff *skb,
 373                        unsigned int data_len,
 374                        u_int8_t pf,
 375                        unsigned int hooknum,
 376                        const struct net_device *indev,
 377                        const struct net_device *outdev,
 378                        const char *prefix, unsigned int plen)
 379{
 380        struct nfulnl_msg_packet_hdr pmsg;
 381        struct nlmsghdr *nlh;
 382        struct nfgenmsg *nfmsg;
 383        sk_buff_data_t old_tail = inst->skb->tail;
 384        struct sock *sk;
 385
 386        nlh = nlmsg_put(inst->skb, 0, 0,
 387                        NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 388                        sizeof(struct nfgenmsg), 0);
 389        if (!nlh)
 390                return -1;
 391        nfmsg = nlmsg_data(nlh);
 392        nfmsg->nfgen_family = pf;
 393        nfmsg->version = NFNETLINK_V0;
 394        nfmsg->res_id = htons(inst->group_num);
 395
 396        pmsg.hw_protocol        = skb->protocol;
 397        pmsg.hook               = hooknum;
 398
 399        if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
 400                goto nla_put_failure;
 401
 402        if (prefix &&
 403            nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
 404                goto nla_put_failure;
 405
 406        if (indev) {
 407#ifndef CONFIG_BRIDGE_NETFILTER
 408                if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 409                                 htonl(indev->ifindex)))
 410                        goto nla_put_failure;
 411#else
 412                if (pf == PF_BRIDGE) {
 413                        /* Case 1: outdev is physical input device, we need to
 414                         * look for bridge group (when called from
 415                         * netfilter_bridge) */
 416                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 417                                         htonl(indev->ifindex)) ||
 418                        /* this is the bridge group "brX" */
 419                        /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 420                            nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 421                                         htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
 422                                goto nla_put_failure;
 423                } else {
 424                        /* Case 2: indev is bridge group, we need to look for
 425                         * physical device (when called from ipv4) */
 426                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 427                                         htonl(indev->ifindex)))
 428                                goto nla_put_failure;
 429                        if (skb->nf_bridge && skb->nf_bridge->physindev &&
 430                            nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 431                                         htonl(skb->nf_bridge->physindev->ifindex)))
 432                                goto nla_put_failure;
 433                }
 434#endif
 435        }
 436
 437        if (outdev) {
 438#ifndef CONFIG_BRIDGE_NETFILTER
 439                if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 440                                 htonl(outdev->ifindex)))
 441                        goto nla_put_failure;
 442#else
 443                if (pf == PF_BRIDGE) {
 444                        /* Case 1: outdev is physical output device, we need to
 445                         * look for bridge group (when called from
 446                         * netfilter_bridge) */
 447                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 448                                         htonl(outdev->ifindex)) ||
 449                        /* this is the bridge group "brX" */
 450                        /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 451                            nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 452                                         htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
 453                                goto nla_put_failure;
 454                } else {
 455                        /* Case 2: indev is a bridge group, we need to look
 456                         * for physical device (when called from ipv4) */
 457                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 458                                         htonl(outdev->ifindex)))
 459                                goto nla_put_failure;
 460                        if (skb->nf_bridge && skb->nf_bridge->physoutdev &&
 461                            nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 462                                         htonl(skb->nf_bridge->physoutdev->ifindex)))
 463                                goto nla_put_failure;
 464                }
 465#endif
 466        }
 467
 468        if (skb->mark &&
 469            nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
 470                goto nla_put_failure;
 471
 472        if (indev && skb->dev &&
 473            skb->mac_header != skb->network_header) {
 474                struct nfulnl_msg_packet_hw phw;
 475                int len = dev_parse_header(skb, phw.hw_addr);
 476                if (len > 0) {
 477                        phw.hw_addrlen = htons(len);
 478                        if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
 479                                goto nla_put_failure;
 480                }
 481        }
 482
 483        if (indev && skb_mac_header_was_set(skb)) {
 484                if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 485                    nla_put_be16(inst->skb, NFULA_HWLEN,
 486                                 htons(skb->dev->hard_header_len)) ||
 487                    nla_put(inst->skb, NFULA_HWHEADER, skb->dev->hard_header_len,
 488                            skb_mac_header(skb)))
 489                        goto nla_put_failure;
 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                if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
 499                        goto nla_put_failure;
 500        }
 501
 502        /* UID */
 503        sk = skb->sk;
 504        if (sk && sk->sk_state != TCP_TIME_WAIT) {
 505                read_lock_bh(&sk->sk_callback_lock);
 506                if (sk->sk_socket && sk->sk_socket->file) {
 507                        struct file *file = sk->sk_socket->file;
 508                        __be32 uid = htonl(file->f_cred->fsuid);
 509                        __be32 gid = htonl(file->f_cred->fsgid);
 510                        read_unlock_bh(&sk->sk_callback_lock);
 511                        if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
 512                            nla_put_be32(inst->skb, NFULA_GID, gid))
 513                                goto nla_put_failure;
 514                } else
 515                        read_unlock_bh(&sk->sk_callback_lock);
 516        }
 517
 518        /* local sequence number */
 519        if ((inst->flags & NFULNL_CFG_F_SEQ) &&
 520            nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
 521                goto nla_put_failure;
 522
 523        /* global sequence number */
 524        if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
 525            nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
 526                         htonl(atomic_inc_return(&global_seq))))
 527                goto nla_put_failure;
 528
 529        if (data_len) {
 530                struct nlattr *nla;
 531                int size = nla_attr_size(data_len);
 532
 533                if (skb_tailroom(inst->skb) < nla_total_size(data_len)) {
 534                        printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
 535                        return -1;
 536                }
 537
 538                nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
 539                nla->nla_type = NFULA_PAYLOAD;
 540                nla->nla_len = size;
 541
 542                if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 543                        BUG();
 544        }
 545
 546        nlh->nlmsg_len = inst->skb->tail - old_tail;
 547        return 0;
 548
 549nla_put_failure:
 550        PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 551        return -1;
 552}
 553
 554#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 555
 556static struct nf_loginfo default_loginfo = {
 557        .type =         NF_LOG_TYPE_ULOG,
 558        .u = {
 559                .ulog = {
 560                        .copy_len       = 0xffff,
 561                        .group          = 0,
 562                        .qthreshold     = 1,
 563                },
 564        },
 565};
 566
 567/* log handler for internal netfilter logging api */
 568void
 569nfulnl_log_packet(u_int8_t pf,
 570                  unsigned int hooknum,
 571                  const struct sk_buff *skb,
 572                  const struct net_device *in,
 573                  const struct net_device *out,
 574                  const struct nf_loginfo *li_user,
 575                  const char *prefix)
 576{
 577        unsigned int size, data_len;
 578        struct nfulnl_instance *inst;
 579        const struct nf_loginfo *li;
 580        unsigned int qthreshold;
 581        unsigned int plen;
 582
 583        if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 584                li = li_user;
 585        else
 586                li = &default_loginfo;
 587
 588        inst = instance_lookup_get(li->u.ulog.group);
 589        if (!inst)
 590                return;
 591
 592        plen = 0;
 593        if (prefix)
 594                plen = strlen(prefix) + 1;
 595
 596        /* FIXME: do we want to make the size calculation conditional based on
 597         * what is actually present?  way more branches and checks, but more
 598         * memory efficient... */
 599        size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
 600                + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 601                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 602                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 603#ifdef CONFIG_BRIDGE_NETFILTER
 604                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 605                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 606#endif
 607                + nla_total_size(sizeof(u_int32_t))     /* mark */
 608                + nla_total_size(sizeof(u_int32_t))     /* uid */
 609                + nla_total_size(sizeof(u_int32_t))     /* gid */
 610                + nla_total_size(plen)                  /* prefix */
 611                + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 612                + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp));
 613
 614        if (in && skb_mac_header_was_set(skb)) {
 615                size +=   nla_total_size(skb->dev->hard_header_len)
 616                        + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 617                        + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 618        }
 619
 620        spin_lock_bh(&inst->lock);
 621
 622        if (inst->flags & NFULNL_CFG_F_SEQ)
 623                size += nla_total_size(sizeof(u_int32_t));
 624        if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 625                size += nla_total_size(sizeof(u_int32_t));
 626
 627        qthreshold = inst->qthreshold;
 628        /* per-rule qthreshold overrides per-instance */
 629        if (li->u.ulog.qthreshold)
 630                if (qthreshold > li->u.ulog.qthreshold)
 631                        qthreshold = li->u.ulog.qthreshold;
 632
 633
 634        switch (inst->copy_mode) {
 635        case NFULNL_COPY_META:
 636        case NFULNL_COPY_NONE:
 637                data_len = 0;
 638                break;
 639
 640        case NFULNL_COPY_PACKET:
 641                if (inst->copy_range == 0
 642                    || inst->copy_range > skb->len)
 643                        data_len = skb->len;
 644                else
 645                        data_len = inst->copy_range;
 646
 647                size += nla_total_size(data_len);
 648                break;
 649
 650        case NFULNL_COPY_DISABLED:
 651        default:
 652                goto unlock_and_release;
 653        }
 654
 655        if (inst->skb &&
 656            size > skb_tailroom(inst->skb) - sizeof(struct nfgenmsg)) {
 657                /* either the queue len is too high or we don't have
 658                 * enough room in the skb left. flush to userspace. */
 659                __nfulnl_flush(inst);
 660        }
 661
 662        if (!inst->skb) {
 663                inst->skb = nfulnl_alloc_skb(inst->nlbufsiz, size);
 664                if (!inst->skb)
 665                        goto alloc_failure;
 666        }
 667
 668        inst->qlen++;
 669
 670        __build_packet_message(inst, skb, data_len, pf,
 671                                hooknum, in, out, prefix, plen);
 672
 673        if (inst->qlen >= qthreshold)
 674                __nfulnl_flush(inst);
 675        /* timer_pending always called within inst->lock, so there
 676         * is no chance of a race here */
 677        else 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
 683unlock_and_release:
 684        spin_unlock_bh(&inst->lock);
 685        instance_put(inst);
 686        return;
 687
 688alloc_failure:
 689        /* FIXME: statistics */
 690        goto unlock_and_release;
 691}
 692EXPORT_SYMBOL_GPL(nfulnl_log_packet);
 693
 694static int
 695nfulnl_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 && n->protocol == NETLINK_NETFILTER) {
 701                int i;
 702
 703                /* destroy all instances for this pid */
 704                spin_lock_bh(&instances_lock);
 705                for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 706                        struct hlist_node *tmp, *t2;
 707                        struct nfulnl_instance *inst;
 708                        struct hlist_head *head = &instance_table[i];
 709
 710                        hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
 711                                if ((net_eq(n->net, &init_net)) &&
 712                                    (n->pid == inst->peer_pid))
 713                                        __instance_destroy(inst);
 714                        }
 715                }
 716                spin_unlock_bh(&instances_lock);
 717        }
 718        return NOTIFY_DONE;
 719}
 720
 721static struct notifier_block nfulnl_rtnl_notifier = {
 722        .notifier_call  = nfulnl_rcv_nl_event,
 723};
 724
 725static int
 726nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 727                   const struct nlmsghdr *nlh,
 728                   const struct nlattr * const nfqa[])
 729{
 730        return -ENOTSUPP;
 731}
 732
 733static struct nf_logger nfulnl_logger __read_mostly = {
 734        .name   = "nfnetlink_log",
 735        .logfn  = &nfulnl_log_packet,
 736        .me     = THIS_MODULE,
 737};
 738
 739static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 740        [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 741        [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 742        [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 743        [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 744        [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 745        [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 746};
 747
 748static int
 749nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 750                   const struct nlmsghdr *nlh,
 751                   const struct nlattr * const nfula[])
 752{
 753        struct nfgenmsg *nfmsg = nlmsg_data(nlh);
 754        u_int16_t group_num = ntohs(nfmsg->res_id);
 755        struct nfulnl_instance *inst;
 756        struct nfulnl_msg_config_cmd *cmd = NULL;
 757        int ret = 0;
 758
 759        if (nfula[NFULA_CFG_CMD]) {
 760                u_int8_t pf = nfmsg->nfgen_family;
 761                cmd = nla_data(nfula[NFULA_CFG_CMD]);
 762
 763                /* Commands without queue context */
 764                switch (cmd->command) {
 765                case NFULNL_CFG_CMD_PF_BIND:
 766                        return nf_log_bind_pf(pf, &nfulnl_logger);
 767                case NFULNL_CFG_CMD_PF_UNBIND:
 768                        nf_log_unbind_pf(pf);
 769                        return 0;
 770                }
 771        }
 772
 773        inst = instance_lookup_get(group_num);
 774        if (inst && inst->peer_pid != NETLINK_CB(skb).pid) {
 775                ret = -EPERM;
 776                goto out_put;
 777        }
 778
 779        if (cmd != NULL) {
 780                switch (cmd->command) {
 781                case NFULNL_CFG_CMD_BIND:
 782                        if (inst) {
 783                                ret = -EBUSY;
 784                                goto out_put;
 785                        }
 786
 787                        inst = instance_create(group_num,
 788                                               NETLINK_CB(skb).pid);
 789                        if (IS_ERR(inst)) {
 790                                ret = PTR_ERR(inst);
 791                                goto out;
 792                        }
 793                        break;
 794                case NFULNL_CFG_CMD_UNBIND:
 795                        if (!inst) {
 796                                ret = -ENODEV;
 797                                goto out;
 798                        }
 799
 800                        instance_destroy(inst);
 801                        goto out_put;
 802                default:
 803                        ret = -ENOTSUPP;
 804                        break;
 805                }
 806        }
 807
 808        if (nfula[NFULA_CFG_MODE]) {
 809                struct nfulnl_msg_config_mode *params;
 810                params = nla_data(nfula[NFULA_CFG_MODE]);
 811
 812                if (!inst) {
 813                        ret = -ENODEV;
 814                        goto out;
 815                }
 816                nfulnl_set_mode(inst, params->copy_mode,
 817                                ntohl(params->copy_range));
 818        }
 819
 820        if (nfula[NFULA_CFG_TIMEOUT]) {
 821                __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 822
 823                if (!inst) {
 824                        ret = -ENODEV;
 825                        goto out;
 826                }
 827                nfulnl_set_timeout(inst, ntohl(timeout));
 828        }
 829
 830        if (nfula[NFULA_CFG_NLBUFSIZ]) {
 831                __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 832
 833                if (!inst) {
 834                        ret = -ENODEV;
 835                        goto out;
 836                }
 837                nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 838        }
 839
 840        if (nfula[NFULA_CFG_QTHRESH]) {
 841                __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 842
 843                if (!inst) {
 844                        ret = -ENODEV;
 845                        goto out;
 846                }
 847                nfulnl_set_qthresh(inst, ntohl(qthresh));
 848        }
 849
 850        if (nfula[NFULA_CFG_FLAGS]) {
 851                __be16 flags = nla_get_be16(nfula[NFULA_CFG_FLAGS]);
 852
 853                if (!inst) {
 854                        ret = -ENODEV;
 855                        goto out;
 856                }
 857                nfulnl_set_flags(inst, ntohs(flags));
 858        }
 859
 860out_put:
 861        instance_put(inst);
 862out:
 863        return ret;
 864}
 865
 866static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 867        [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 868                                    .attr_count = NFULA_MAX, },
 869        [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 870                                    .attr_count = NFULA_CFG_MAX,
 871                                    .policy = nfula_cfg_policy },
 872};
 873
 874static const struct nfnetlink_subsystem nfulnl_subsys = {
 875        .name           = "log",
 876        .subsys_id      = NFNL_SUBSYS_ULOG,
 877        .cb_count       = NFULNL_MSG_MAX,
 878        .cb             = nfulnl_cb,
 879};
 880
 881#ifdef CONFIG_PROC_FS
 882struct iter_state {
 883        unsigned int bucket;
 884};
 885
 886static struct hlist_node *get_first(struct iter_state *st)
 887{
 888        if (!st)
 889                return NULL;
 890
 891        for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 892                if (!hlist_empty(&instance_table[st->bucket]))
 893                        return rcu_dereference_bh(hlist_first_rcu(&instance_table[st->bucket]));
 894        }
 895        return NULL;
 896}
 897
 898static struct hlist_node *get_next(struct iter_state *st, struct hlist_node *h)
 899{
 900        h = rcu_dereference_bh(hlist_next_rcu(h));
 901        while (!h) {
 902                if (++st->bucket >= INSTANCE_BUCKETS)
 903                        return NULL;
 904
 905                h = rcu_dereference_bh(hlist_first_rcu(&instance_table[st->bucket]));
 906        }
 907        return h;
 908}
 909
 910static struct hlist_node *get_idx(struct iter_state *st, loff_t pos)
 911{
 912        struct hlist_node *head;
 913        head = get_first(st);
 914
 915        if (head)
 916                while (pos && (head = get_next(st, head)))
 917                        pos--;
 918        return pos ? NULL : head;
 919}
 920
 921static void *seq_start(struct seq_file *seq, loff_t *pos)
 922        __acquires(rcu_bh)
 923{
 924        rcu_read_lock_bh();
 925        return get_idx(seq->private, *pos);
 926}
 927
 928static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 929{
 930        (*pos)++;
 931        return get_next(s->private, v);
 932}
 933
 934static void seq_stop(struct seq_file *s, void *v)
 935        __releases(rcu_bh)
 936{
 937        rcu_read_unlock_bh();
 938}
 939
 940static int seq_show(struct seq_file *s, void *v)
 941{
 942        const struct nfulnl_instance *inst = v;
 943
 944        return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
 945                          inst->group_num,
 946                          inst->peer_pid, inst->qlen,
 947                          inst->copy_mode, inst->copy_range,
 948                          inst->flushtimeout, atomic_read(&inst->use));
 949}
 950
 951static const struct seq_operations nful_seq_ops = {
 952        .start  = seq_start,
 953        .next   = seq_next,
 954        .stop   = seq_stop,
 955        .show   = seq_show,
 956};
 957
 958static int nful_open(struct inode *inode, struct file *file)
 959{
 960        return seq_open_private(file, &nful_seq_ops,
 961                        sizeof(struct iter_state));
 962}
 963
 964static const struct file_operations nful_file_ops = {
 965        .owner   = THIS_MODULE,
 966        .open    = nful_open,
 967        .read    = seq_read,
 968        .llseek  = seq_lseek,
 969        .release = seq_release_private,
 970};
 971
 972#endif /* PROC_FS */
 973
 974static int __init nfnetlink_log_init(void)
 975{
 976        int i, status = -ENOMEM;
 977
 978        for (i = 0; i < INSTANCE_BUCKETS; i++)
 979                INIT_HLIST_HEAD(&instance_table[i]);
 980
 981        /* it's not really all that important to have a random value, so
 982         * we can do this from the init function, even if there hasn't
 983         * been that much entropy yet */
 984        get_random_bytes(&hash_init, sizeof(hash_init));
 985
 986        netlink_register_notifier(&nfulnl_rtnl_notifier);
 987        status = nfnetlink_subsys_register(&nfulnl_subsys);
 988        if (status < 0) {
 989                printk(KERN_ERR "log: failed to create netlink socket\n");
 990                goto cleanup_netlink_notifier;
 991        }
 992
 993        status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
 994        if (status < 0) {
 995                printk(KERN_ERR "log: failed to register logger\n");
 996                goto cleanup_subsys;
 997        }
 998
 999#ifdef CONFIG_PROC_FS
1000        if (!proc_create("nfnetlink_log", 0440,
1001                         proc_net_netfilter, &nful_file_ops)) {
1002                status = -ENOMEM;
1003                goto cleanup_logger;
1004        }
1005#endif
1006        return status;
1007
1008#ifdef CONFIG_PROC_FS
1009cleanup_logger:
1010        nf_log_unregister(&nfulnl_logger);
1011#endif
1012cleanup_subsys:
1013        nfnetlink_subsys_unregister(&nfulnl_subsys);
1014cleanup_netlink_notifier:
1015        netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1016        return status;
1017}
1018
1019static void __exit nfnetlink_log_fini(void)
1020{
1021        nf_log_unregister(&nfulnl_logger);
1022#ifdef CONFIG_PROC_FS
1023        remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1024#endif
1025        nfnetlink_subsys_unregister(&nfulnl_subsys);
1026        netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1027}
1028
1029MODULE_DESCRIPTION("netfilter userspace logging");
1030MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1031MODULE_LICENSE("GPL");
1032MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1033
1034module_init(nfnetlink_log_init);
1035module_exit(nfnetlink_log_fini);
1036
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.