linux/net/netfilter/nfnetlink_log.c
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   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 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
   7 *
   8 * Based on the old ipv4-only ipt_ULOG.c:
   9 * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License version 2 as
  13 * published by the Free Software Foundation.
  14 */
  15
  16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18#include <linux/module.h>
  19#include <linux/skbuff.h>
  20#include <linux/if_arp.h>
  21#include <linux/init.h>
  22#include <linux/ip.h>
  23#include <linux/ipv6.h>
  24#include <linux/netdevice.h>
  25#include <linux/netfilter.h>
  26#include <linux/netfilter_bridge.h>
  27#include <net/netlink.h>
  28#include <linux/netfilter/nfnetlink.h>
  29#include <linux/netfilter/nfnetlink_log.h>
  30#include <linux/spinlock.h>
  31#include <linux/sysctl.h>
  32#include <linux/proc_fs.h>
  33#include <linux/security.h>
  34#include <linux/list.h>
  35#include <linux/slab.h>
  36#include <net/sock.h>
  37#include <net/netfilter/nf_log.h>
  38#include <net/netns/generic.h>
  39#include <net/netfilter/nfnetlink_log.h>
  40
  41#include <linux/atomic.h>
  42
  43#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
  44#include "../bridge/br_private.h"
  45#endif
  46
  47#define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  48#define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  49#define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  50/* max packet size is limited by 16-bit struct nfattr nfa_len field */
  51#define NFULNL_COPY_RANGE_MAX   (0xFFFF - NLA_HDRLEN)
  52
  53#define PRINTR(x, args...)      do { if (net_ratelimit()) \
  54                                     printk(x, ## args); } while (0);
  55
  56struct nfulnl_instance {
  57        struct hlist_node hlist;        /* global list of instances */
  58        spinlock_t lock;
  59        atomic_t use;                   /* use count */
  60
  61        unsigned int qlen;              /* number of nlmsgs in skb */
  62        struct sk_buff *skb;            /* pre-allocatd skb */
  63        struct timer_list timer;
  64        struct net *net;
  65        struct user_namespace *peer_user_ns;    /* User namespace of the peer process */
  66        u32 peer_portid;                /* PORTID of the peer process */
  67
  68        /* configurable parameters */
  69        unsigned int flushtimeout;      /* timeout until queue flush */
  70        unsigned int nlbufsiz;          /* netlink buffer allocation size */
  71        unsigned int qthreshold;        /* threshold of the queue */
  72        u_int32_t copy_range;
  73        u_int32_t seq;                  /* instance-local sequential counter */
  74        u_int16_t group_num;            /* number of this queue */
  75        u_int16_t flags;
  76        u_int8_t copy_mode;
  77        struct rcu_head rcu;
  78};
  79
  80#define INSTANCE_BUCKETS        16
  81
  82static int nfnl_log_net_id __read_mostly;
  83
  84struct nfnl_log_net {
  85        spinlock_t instances_lock;
  86        struct hlist_head instance_table[INSTANCE_BUCKETS];
  87        atomic_t global_seq;
  88};
  89
  90static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
  91{
  92        return net_generic(net, nfnl_log_net_id);
  93}
  94
  95static inline u_int8_t instance_hashfn(u_int16_t group_num)
  96{
  97        return ((group_num & 0xff) % INSTANCE_BUCKETS);
  98}
  99
 100static struct nfulnl_instance *
 101__instance_lookup(struct nfnl_log_net *log, u_int16_t group_num)
 102{
 103        struct hlist_head *head;
 104        struct nfulnl_instance *inst;
 105
 106        head = &log->instance_table[instance_hashfn(group_num)];
 107        hlist_for_each_entry_rcu(inst, head, hlist) {
 108                if (inst->group_num == group_num)
 109                        return inst;
 110        }
 111        return NULL;
 112}
 113
 114static inline void
 115instance_get(struct nfulnl_instance *inst)
 116{
 117        atomic_inc(&inst->use);
 118}
 119
 120static struct nfulnl_instance *
 121instance_lookup_get(struct nfnl_log_net *log, u_int16_t group_num)
 122{
 123        struct nfulnl_instance *inst;
 124
 125        rcu_read_lock_bh();
 126        inst = __instance_lookup(log, group_num);
 127        if (inst && !atomic_inc_not_zero(&inst->use))
 128                inst = NULL;
 129        rcu_read_unlock_bh();
 130
 131        return inst;
 132}
 133
 134static void nfulnl_instance_free_rcu(struct rcu_head *head)
 135{
 136        struct nfulnl_instance *inst =
 137                container_of(head, struct nfulnl_instance, rcu);
 138
 139        put_net(inst->net);
 140        kfree(inst);
 141        module_put(THIS_MODULE);
 142}
 143
 144static void
 145instance_put(struct nfulnl_instance *inst)
 146{
 147        if (inst && atomic_dec_and_test(&inst->use))
 148                call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
 149}
 150
 151static void nfulnl_timer(unsigned long data);
 152
 153static struct nfulnl_instance *
 154instance_create(struct net *net, u_int16_t group_num,
 155                u32 portid, struct user_namespace *user_ns)
 156{
 157        struct nfulnl_instance *inst;
 158        struct nfnl_log_net *log = nfnl_log_pernet(net);
 159        int err;
 160
 161        spin_lock_bh(&log->instances_lock);
 162        if (__instance_lookup(log, group_num)) {
 163                err = -EEXIST;
 164                goto out_unlock;
 165        }
 166
 167        inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 168        if (!inst) {
 169                err = -ENOMEM;
 170                goto out_unlock;
 171        }
 172
 173        if (!try_module_get(THIS_MODULE)) {
 174                kfree(inst);
 175                err = -EAGAIN;
 176                goto out_unlock;
 177        }
 178
 179        INIT_HLIST_NODE(&inst->hlist);
 180        spin_lock_init(&inst->lock);
 181        /* needs to be two, since we _put() after creation */
 182        atomic_set(&inst->use, 2);
 183
 184        setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
 185
 186        inst->net = get_net(net);
 187        inst->peer_user_ns = user_ns;
 188        inst->peer_portid = portid;
 189        inst->group_num = group_num;
 190
 191        inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 192        inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 193        inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 194        inst->copy_mode         = NFULNL_COPY_PACKET;
 195        inst->copy_range        = NFULNL_COPY_RANGE_MAX;
 196
 197        hlist_add_head_rcu(&inst->hlist,
 198                       &log->instance_table[instance_hashfn(group_num)]);
 199
 200
 201        spin_unlock_bh(&log->instances_lock);
 202
 203        return inst;
 204
 205out_unlock:
 206        spin_unlock_bh(&log->instances_lock);
 207        return ERR_PTR(err);
 208}
 209
 210static void __nfulnl_flush(struct nfulnl_instance *inst);
 211
 212/* called with BH disabled */
 213static void
 214__instance_destroy(struct nfulnl_instance *inst)
 215{
 216        /* first pull it out of the global list */
 217        hlist_del_rcu(&inst->hlist);
 218
 219        /* then flush all pending packets from skb */
 220
 221        spin_lock(&inst->lock);
 222
 223        /* lockless readers wont be able to use us */
 224        inst->copy_mode = NFULNL_COPY_DISABLED;
 225
 226        if (inst->skb)
 227                __nfulnl_flush(inst);
 228        spin_unlock(&inst->lock);
 229
 230        /* and finally put the refcount */
 231        instance_put(inst);
 232}
 233
 234static inline void
 235instance_destroy(struct nfnl_log_net *log,
 236                 struct nfulnl_instance *inst)
 237{
 238        spin_lock_bh(&log->instances_lock);
 239        __instance_destroy(inst);
 240        spin_unlock_bh(&log->instances_lock);
 241}
 242
 243static int
 244nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 245                  unsigned int range)
 246{
 247        int status = 0;
 248
 249        spin_lock_bh(&inst->lock);
 250
 251        switch (mode) {
 252        case NFULNL_COPY_NONE:
 253        case NFULNL_COPY_META:
 254                inst->copy_mode = mode;
 255                inst->copy_range = 0;
 256                break;
 257
 258        case NFULNL_COPY_PACKET:
 259                inst->copy_mode = mode;
 260                if (range == 0)
 261                        range = NFULNL_COPY_RANGE_MAX;
 262                inst->copy_range = min_t(unsigned int,
 263                                         range, NFULNL_COPY_RANGE_MAX);
 264                break;
 265
 266        default:
 267                status = -EINVAL;
 268                break;
 269        }
 270
 271        spin_unlock_bh(&inst->lock);
 272
 273        return status;
 274}
 275
 276static int
 277nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 278{
 279        int status;
 280
 281        spin_lock_bh(&inst->lock);
 282        if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 283                status = -ERANGE;
 284        else if (nlbufsiz > 131072)
 285                status = -ERANGE;
 286        else {
 287                inst->nlbufsiz = nlbufsiz;
 288                status = 0;
 289        }
 290        spin_unlock_bh(&inst->lock);
 291
 292        return status;
 293}
 294
 295static int
 296nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 297{
 298        spin_lock_bh(&inst->lock);
 299        inst->flushtimeout = timeout;
 300        spin_unlock_bh(&inst->lock);
 301
 302        return 0;
 303}
 304
 305static int
 306nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 307{
 308        spin_lock_bh(&inst->lock);
 309        inst->qthreshold = qthresh;
 310        spin_unlock_bh(&inst->lock);
 311
 312        return 0;
 313}
 314
 315static int
 316nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 317{
 318        spin_lock_bh(&inst->lock);
 319        inst->flags = flags;
 320        spin_unlock_bh(&inst->lock);
 321
 322        return 0;
 323}
 324
 325static struct sk_buff *
 326nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size,
 327                 unsigned int pkt_size)
 328{
 329        struct sk_buff *skb;
 330        unsigned int n;
 331
 332        /* alloc skb which should be big enough for a whole multipart
 333         * message.  WARNING: has to be <= 128k due to slab restrictions */
 334
 335        n = max(inst_size, pkt_size);
 336        skb = nfnetlink_alloc_skb(net, n, peer_portid, GFP_ATOMIC);
 337        if (!skb) {
 338                if (n > pkt_size) {
 339                        /* try to allocate only as much as we need for current
 340                         * packet */
 341
 342                        skb = nfnetlink_alloc_skb(net, pkt_size,
 343                                                  peer_portid, GFP_ATOMIC);
 344                }
 345        }
 346
 347        return skb;
 348}
 349
 350static void
 351__nfulnl_send(struct nfulnl_instance *inst)
 352{
 353        if (inst->qlen > 1) {
 354                struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
 355                                                 NLMSG_DONE,
 356                                                 sizeof(struct nfgenmsg),
 357                                                 0);
 358                if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n",
 359                              inst->skb->len, skb_tailroom(inst->skb))) {
 360                        kfree_skb(inst->skb);
 361                        goto out;
 362                }
 363        }
 364        nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
 365                          MSG_DONTWAIT);
 366out:
 367        inst->qlen = 0;
 368        inst->skb = NULL;
 369}
 370
 371static void
 372__nfulnl_flush(struct nfulnl_instance *inst)
 373{
 374        /* timer holds a reference */
 375        if (del_timer(&inst->timer))
 376                instance_put(inst);
 377        if (inst->skb)
 378                __nfulnl_send(inst);
 379}
 380
 381static void
 382nfulnl_timer(unsigned long data)
 383{
 384        struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 385
 386        spin_lock_bh(&inst->lock);
 387        if (inst->skb)
 388                __nfulnl_send(inst);
 389        spin_unlock_bh(&inst->lock);
 390        instance_put(inst);
 391}
 392
 393/* This is an inline function, we don't really care about a long
 394 * list of arguments */
 395static inline int
 396__build_packet_message(struct nfnl_log_net *log,
 397                        struct nfulnl_instance *inst,
 398                        const struct sk_buff *skb,
 399                        unsigned int data_len,
 400                        u_int8_t pf,
 401                        unsigned int hooknum,
 402                        const struct net_device *indev,
 403                        const struct net_device *outdev,
 404                        const char *prefix, unsigned int plen)
 405{
 406        struct nfulnl_msg_packet_hdr pmsg;
 407        struct nlmsghdr *nlh;
 408        struct nfgenmsg *nfmsg;
 409        sk_buff_data_t old_tail = inst->skb->tail;
 410        struct sock *sk;
 411        const unsigned char *hwhdrp;
 412
 413        nlh = nlmsg_put(inst->skb, 0, 0,
 414                        NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 415                        sizeof(struct nfgenmsg), 0);
 416        if (!nlh)
 417                return -1;
 418        nfmsg = nlmsg_data(nlh);
 419        nfmsg->nfgen_family = pf;
 420        nfmsg->version = NFNETLINK_V0;
 421        nfmsg->res_id = htons(inst->group_num);
 422
 423        memset(&pmsg, 0, sizeof(pmsg));
 424        pmsg.hw_protocol        = skb->protocol;
 425        pmsg.hook               = hooknum;
 426
 427        if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
 428                goto nla_put_failure;
 429
 430        if (prefix &&
 431            nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
 432                goto nla_put_failure;
 433
 434        if (indev) {
 435#if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 436                if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 437                                 htonl(indev->ifindex)))
 438                        goto nla_put_failure;
 439#else
 440                if (pf == PF_BRIDGE) {
 441                        /* Case 1: outdev is physical input device, we need to
 442                         * look for bridge group (when called from
 443                         * netfilter_bridge) */
 444                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 445                                         htonl(indev->ifindex)) ||
 446                        /* this is the bridge group "brX" */
 447                        /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 448                            nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 449                                         htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
 450                                goto nla_put_failure;
 451                } else {
 452                        struct net_device *physindev;
 453
 454                        /* Case 2: indev is bridge group, we need to look for
 455                         * physical device (when called from ipv4) */
 456                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 457                                         htonl(indev->ifindex)))
 458                                goto nla_put_failure;
 459
 460                        physindev = nf_bridge_get_physindev(skb);
 461                        if (physindev &&
 462                            nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 463                                         htonl(physindev->ifindex)))
 464                                goto nla_put_failure;
 465                }
 466#endif
 467        }
 468
 469        if (outdev) {
 470#if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 471                if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 472                                 htonl(outdev->ifindex)))
 473                        goto nla_put_failure;
 474#else
 475                if (pf == PF_BRIDGE) {
 476                        /* Case 1: outdev is physical output device, we need to
 477                         * look for bridge group (when called from
 478                         * netfilter_bridge) */
 479                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 480                                         htonl(outdev->ifindex)) ||
 481                        /* this is the bridge group "brX" */
 482                        /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 483                            nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 484                                         htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
 485                                goto nla_put_failure;
 486                } else {
 487                        struct net_device *physoutdev;
 488
 489                        /* Case 2: indev is a bridge group, we need to look
 490                         * for physical device (when called from ipv4) */
 491                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 492                                         htonl(outdev->ifindex)))
 493                                goto nla_put_failure;
 494
 495                        physoutdev = nf_bridge_get_physoutdev(skb);
 496                        if (physoutdev &&
 497                            nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 498                                         htonl(physoutdev->ifindex)))
 499                                goto nla_put_failure;
 500                }
 501#endif
 502        }
 503
 504        if (skb->mark &&
 505            nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
 506                goto nla_put_failure;
 507
 508        if (indev && skb->dev &&
 509            skb->mac_header != skb->network_header) {
 510                struct nfulnl_msg_packet_hw phw;
 511                int len;
 512
 513                memset(&phw, 0, sizeof(phw));
 514                len = dev_parse_header(skb, phw.hw_addr);
 515                if (len > 0) {
 516                        phw.hw_addrlen = htons(len);
 517                        if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
 518                                goto nla_put_failure;
 519                }
 520        }
 521
 522        if (indev && skb_mac_header_was_set(skb)) {
 523                if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 524                    nla_put_be16(inst->skb, NFULA_HWLEN,
 525                                 htons(skb->dev->hard_header_len)))
 526                        goto nla_put_failure;
 527
 528                hwhdrp = skb_mac_header(skb);
 529
 530                if (skb->dev->type == ARPHRD_SIT)
 531                        hwhdrp -= ETH_HLEN;
 532
 533                if (hwhdrp >= skb->head &&
 534                    nla_put(inst->skb, NFULA_HWHEADER,
 535                            skb->dev->hard_header_len, hwhdrp))
 536                        goto nla_put_failure;
 537        }
 538
 539        if (skb->tstamp.tv64) {
 540                struct nfulnl_msg_packet_timestamp ts;
 541                struct timeval tv = ktime_to_timeval(skb->tstamp);
 542                ts.sec = cpu_to_be64(tv.tv_sec);
 543                ts.usec = cpu_to_be64(tv.tv_usec);
 544
 545                if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
 546                        goto nla_put_failure;
 547        }
 548
 549        /* UID */
 550        sk = skb->sk;
 551        if (sk && sk_fullsock(sk)) {
 552                read_lock_bh(&sk->sk_callback_lock);
 553                if (sk->sk_socket && sk->sk_socket->file) {
 554                        struct file *file = sk->sk_socket->file;
 555                        const struct cred *cred = file->f_cred;
 556                        struct user_namespace *user_ns = inst->peer_user_ns;
 557                        __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
 558                        __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
 559                        read_unlock_bh(&sk->sk_callback_lock);
 560                        if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
 561                            nla_put_be32(inst->skb, NFULA_GID, gid))
 562                                goto nla_put_failure;
 563                } else
 564                        read_unlock_bh(&sk->sk_callback_lock);
 565        }
 566
 567        /* local sequence number */
 568        if ((inst->flags & NFULNL_CFG_F_SEQ) &&
 569            nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
 570                goto nla_put_failure;
 571
 572        /* global sequence number */
 573        if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
 574            nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
 575                         htonl(atomic_inc_return(&log->global_seq))))
 576                goto nla_put_failure;
 577
 578        if (data_len) {
 579                struct nlattr *nla;
 580                int size = nla_attr_size(data_len);
 581
 582                if (skb_tailroom(inst->skb) < nla_total_size(data_len))
 583                        goto nla_put_failure;
 584
 585                nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
 586                nla->nla_type = NFULA_PAYLOAD;
 587                nla->nla_len = size;
 588
 589                if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 590                        BUG();
 591        }
 592
 593        nlh->nlmsg_len = inst->skb->tail - old_tail;
 594        return 0;
 595
 596nla_put_failure:
 597        PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 598        return -1;
 599}
 600
 601#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 602
 603static struct nf_loginfo default_loginfo = {
 604        .type =         NF_LOG_TYPE_ULOG,
 605        .u = {
 606                .ulog = {
 607                        .copy_len       = 0xffff,
 608                        .group          = 0,
 609                        .qthreshold     = 1,
 610                },
 611        },
 612};
 613
 614/* log handler for internal netfilter logging api */
 615void
 616nfulnl_log_packet(struct net *net,
 617                  u_int8_t pf,
 618                  unsigned int hooknum,
 619                  const struct sk_buff *skb,
 620                  const struct net_device *in,
 621                  const struct net_device *out,
 622                  const struct nf_loginfo *li_user,
 623                  const char *prefix)
 624{
 625        unsigned int size, data_len;
 626        struct nfulnl_instance *inst;
 627        const struct nf_loginfo *li;
 628        unsigned int qthreshold;
 629        unsigned int plen;
 630        struct nfnl_log_net *log = nfnl_log_pernet(net);
 631
 632        if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 633                li = li_user;
 634        else
 635                li = &default_loginfo;
 636
 637        inst = instance_lookup_get(log, li->u.ulog.group);
 638        if (!inst)
 639                return;
 640
 641        plen = 0;
 642        if (prefix)
 643                plen = strlen(prefix) + 1;
 644
 645        /* FIXME: do we want to make the size calculation conditional based on
 646         * what is actually present?  way more branches and checks, but more
 647         * memory efficient... */
 648        size =    nlmsg_total_size(sizeof(struct nfgenmsg))
 649                + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 650                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 651                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 652#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 653                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 654                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 655#endif
 656                + nla_total_size(sizeof(u_int32_t))     /* mark */
 657                + nla_total_size(sizeof(u_int32_t))     /* uid */
 658                + nla_total_size(sizeof(u_int32_t))     /* gid */
 659                + nla_total_size(plen)                  /* prefix */
 660                + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 661                + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
 662                + nla_total_size(sizeof(struct nfgenmsg));      /* NLMSG_DONE */
 663
 664        if (in && skb_mac_header_was_set(skb)) {
 665                size +=   nla_total_size(skb->dev->hard_header_len)
 666                        + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 667                        + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 668        }
 669
 670        spin_lock_bh(&inst->lock);
 671
 672        if (inst->flags & NFULNL_CFG_F_SEQ)
 673                size += nla_total_size(sizeof(u_int32_t));
 674        if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 675                size += nla_total_size(sizeof(u_int32_t));
 676
 677        qthreshold = inst->qthreshold;
 678        /* per-rule qthreshold overrides per-instance */
 679        if (li->u.ulog.qthreshold)
 680                if (qthreshold > li->u.ulog.qthreshold)
 681                        qthreshold = li->u.ulog.qthreshold;
 682
 683
 684        switch (inst->copy_mode) {
 685        case NFULNL_COPY_META:
 686        case NFULNL_COPY_NONE:
 687                data_len = 0;
 688                break;
 689
 690        case NFULNL_COPY_PACKET:
 691                if (inst->copy_range > skb->len)
 692                        data_len = skb->len;
 693                else
 694                        data_len = inst->copy_range;
 695
 696                size += nla_total_size(data_len);
 697                break;
 698
 699        case NFULNL_COPY_DISABLED:
 700        default:
 701                goto unlock_and_release;
 702        }
 703
 704        if (inst->skb && size > skb_tailroom(inst->skb)) {
 705                /* either the queue len is too high or we don't have
 706                 * enough room in the skb left. flush to userspace. */
 707                __nfulnl_flush(inst);
 708        }
 709
 710        if (!inst->skb) {
 711                inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
 712                                             inst->nlbufsiz, size);
 713                if (!inst->skb)
 714                        goto alloc_failure;
 715        }
 716
 717        inst->qlen++;
 718
 719        __build_packet_message(log, inst, skb, data_len, pf,
 720                                hooknum, in, out, prefix, plen);
 721
 722        if (inst->qlen >= qthreshold)
 723                __nfulnl_flush(inst);
 724        /* timer_pending always called within inst->lock, so there
 725         * is no chance of a race here */
 726        else if (!timer_pending(&inst->timer)) {
 727                instance_get(inst);
 728                inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 729                add_timer(&inst->timer);
 730        }
 731
 732unlock_and_release:
 733        spin_unlock_bh(&inst->lock);
 734        instance_put(inst);
 735        return;
 736
 737alloc_failure:
 738        /* FIXME: statistics */
 739        goto unlock_and_release;
 740}
 741EXPORT_SYMBOL_GPL(nfulnl_log_packet);
 742
 743static int
 744nfulnl_rcv_nl_event(struct notifier_block *this,
 745                   unsigned long event, void *ptr)
 746{
 747        struct netlink_notify *n = ptr;
 748        struct nfnl_log_net *log = nfnl_log_pernet(n->net);
 749
 750        if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 751                int i;
 752
 753                /* destroy all instances for this portid */
 754                spin_lock_bh(&log->instances_lock);
 755                for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 756                        struct hlist_node *t2;
 757                        struct nfulnl_instance *inst;
 758                        struct hlist_head *head = &log->instance_table[i];
 759
 760                        hlist_for_each_entry_safe(inst, t2, head, hlist) {
 761                                if (n->portid == inst->peer_portid)
 762                                        __instance_destroy(inst);
 763                        }
 764                }
 765                spin_unlock_bh(&log->instances_lock);
 766        }
 767        return NOTIFY_DONE;
 768}
 769
 770static struct notifier_block nfulnl_rtnl_notifier = {
 771        .notifier_call  = nfulnl_rcv_nl_event,
 772};
 773
 774static int
 775nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 776                   const struct nlmsghdr *nlh,
 777                   const struct nlattr * const nfqa[])
 778{
 779        return -ENOTSUPP;
 780}
 781
 782static struct nf_logger nfulnl_logger __read_mostly = {
 783        .name   = "nfnetlink_log",
 784        .type   = NF_LOG_TYPE_ULOG,
 785        .logfn  = &nfulnl_log_packet,
 786        .me     = THIS_MODULE,
 787};
 788
 789static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 790        [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 791        [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 792        [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 793        [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 794        [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 795        [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 796};
 797
 798static int
 799nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 800                   const struct nlmsghdr *nlh,
 801                   const struct nlattr * const nfula[])
 802{
 803        struct nfgenmsg *nfmsg = nlmsg_data(nlh);
 804        u_int16_t group_num = ntohs(nfmsg->res_id);
 805        struct nfulnl_instance *inst;
 806        struct nfulnl_msg_config_cmd *cmd = NULL;
 807        struct net *net = sock_net(ctnl);
 808        struct nfnl_log_net *log = nfnl_log_pernet(net);
 809        int ret = 0;
 810
 811        if (nfula[NFULA_CFG_CMD]) {
 812                u_int8_t pf = nfmsg->nfgen_family;
 813                cmd = nla_data(nfula[NFULA_CFG_CMD]);
 814
 815                /* Commands without queue context */
 816                switch (cmd->command) {
 817                case NFULNL_CFG_CMD_PF_BIND:
 818                        return nf_log_bind_pf(net, pf, &nfulnl_logger);
 819                case NFULNL_CFG_CMD_PF_UNBIND:
 820                        nf_log_unbind_pf(net, pf);
 821                        return 0;
 822                }
 823        }
 824
 825        inst = instance_lookup_get(log, group_num);
 826        if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
 827                ret = -EPERM;
 828                goto out_put;
 829        }
 830
 831        if (cmd != NULL) {
 832                switch (cmd->command) {
 833                case NFULNL_CFG_CMD_BIND:
 834                        if (inst) {
 835                                ret = -EBUSY;
 836                                goto out_put;
 837                        }
 838
 839                        inst = instance_create(net, group_num,
 840                                               NETLINK_CB(skb).portid,
 841                                               sk_user_ns(NETLINK_CB(skb).sk));
 842                        if (IS_ERR(inst)) {
 843                                ret = PTR_ERR(inst);
 844                                goto out;
 845                        }
 846                        break;
 847                case NFULNL_CFG_CMD_UNBIND:
 848                        if (!inst) {
 849                                ret = -ENODEV;
 850                                goto out;
 851                        }
 852
 853                        instance_destroy(log, inst);
 854                        goto out_put;
 855                default:
 856                        ret = -ENOTSUPP;
 857                        break;
 858                }
 859        }
 860
 861        if (nfula[NFULA_CFG_MODE]) {
 862                struct nfulnl_msg_config_mode *params;
 863                params = nla_data(nfula[NFULA_CFG_MODE]);
 864
 865                if (!inst) {
 866                        ret = -ENODEV;
 867                        goto out;
 868                }
 869                nfulnl_set_mode(inst, params->copy_mode,
 870                                ntohl(params->copy_range));
 871        }
 872
 873        if (nfula[NFULA_CFG_TIMEOUT]) {
 874                __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 875
 876                if (!inst) {
 877                        ret = -ENODEV;
 878                        goto out;
 879                }
 880                nfulnl_set_timeout(inst, ntohl(timeout));
 881        }
 882
 883        if (nfula[NFULA_CFG_NLBUFSIZ]) {
 884                __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 885
 886                if (!inst) {
 887                        ret = -ENODEV;
 888                        goto out;
 889                }
 890                nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 891        }
 892
 893        if (nfula[NFULA_CFG_QTHRESH]) {
 894                __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 895
 896                if (!inst) {
 897                        ret = -ENODEV;
 898                        goto out;
 899                }
 900                nfulnl_set_qthresh(inst, ntohl(qthresh));
 901        }
 902
 903        if (nfula[NFULA_CFG_FLAGS]) {
 904                __be16 flags = nla_get_be16(nfula[NFULA_CFG_FLAGS]);
 905
 906                if (!inst) {
 907                        ret = -ENODEV;
 908                        goto out;
 909                }
 910                nfulnl_set_flags(inst, ntohs(flags));
 911        }
 912
 913out_put:
 914        instance_put(inst);
 915out:
 916        return ret;
 917}
 918
 919static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 920        [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 921                                    .attr_count = NFULA_MAX, },
 922        [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 923                                    .attr_count = NFULA_CFG_MAX,
 924                                    .policy = nfula_cfg_policy },
 925};
 926
 927static const struct nfnetlink_subsystem nfulnl_subsys = {
 928        .name           = "log",
 929        .subsys_id      = NFNL_SUBSYS_ULOG,
 930        .cb_count       = NFULNL_MSG_MAX,
 931        .cb             = nfulnl_cb,
 932};
 933
 934#ifdef CONFIG_PROC_FS
 935struct iter_state {
 936        struct seq_net_private p;
 937        unsigned int bucket;
 938};
 939
 940static struct hlist_node *get_first(struct net *net, struct iter_state *st)
 941{
 942        struct nfnl_log_net *log;
 943        if (!st)
 944                return NULL;
 945
 946        log = nfnl_log_pernet(net);
 947
 948        for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 949                struct hlist_head *head = &log->instance_table[st->bucket];
 950
 951                if (!hlist_empty(head))
 952                        return rcu_dereference_bh(hlist_first_rcu(head));
 953        }
 954        return NULL;
 955}
 956
 957static struct hlist_node *get_next(struct net *net, struct iter_state *st,
 958                                   struct hlist_node *h)
 959{
 960        h = rcu_dereference_bh(hlist_next_rcu(h));
 961        while (!h) {
 962                struct nfnl_log_net *log;
 963                struct hlist_head *head;
 964
 965                if (++st->bucket >= INSTANCE_BUCKETS)
 966                        return NULL;
 967
 968                log = nfnl_log_pernet(net);
 969                head = &log->instance_table[st->bucket];
 970                h = rcu_dereference_bh(hlist_first_rcu(head));
 971        }
 972        return h;
 973}
 974
 975static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
 976                                  loff_t pos)
 977{
 978        struct hlist_node *head;
 979        head = get_first(net, st);
 980
 981        if (head)
 982                while (pos && (head = get_next(net, st, head)))
 983                        pos--;
 984        return pos ? NULL : head;
 985}
 986
 987static void *seq_start(struct seq_file *s, loff_t *pos)
 988        __acquires(rcu_bh)
 989{
 990        rcu_read_lock_bh();
 991        return get_idx(seq_file_net(s), s->private, *pos);
 992}
 993
 994static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 995{
 996        (*pos)++;
 997        return get_next(seq_file_net(s), s->private, v);
 998}
 999
1000static void seq_stop(struct seq_file *s, void *v)
1001        __releases(rcu_bh)
1002{
1003        rcu_read_unlock_bh();
1004}
1005
1006static int seq_show(struct seq_file *s, void *v)
1007{
1008        const struct nfulnl_instance *inst = v;
1009
1010        seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u\n",
1011                   inst->group_num,
1012                   inst->peer_portid, inst->qlen,
1013                   inst->copy_mode, inst->copy_range,
1014                   inst->flushtimeout, atomic_read(&inst->use));
1015
1016        return 0;
1017}
1018
1019static const struct seq_operations nful_seq_ops = {
1020        .start  = seq_start,
1021        .next   = seq_next,
1022        .stop   = seq_stop,
1023        .show   = seq_show,
1024};
1025
1026static int nful_open(struct inode *inode, struct file *file)
1027{
1028        return seq_open_net(inode, file, &nful_seq_ops,
1029                            sizeof(struct iter_state));
1030}
1031
1032static const struct file_operations nful_file_ops = {
1033        .owner   = THIS_MODULE,
1034        .open    = nful_open,
1035        .read    = seq_read,
1036        .llseek  = seq_lseek,
1037        .release = seq_release_net,
1038};
1039
1040#endif /* PROC_FS */
1041
1042static int __net_init nfnl_log_net_init(struct net *net)
1043{
1044        unsigned int i;
1045        struct nfnl_log_net *log = nfnl_log_pernet(net);
1046
1047        for (i = 0; i < INSTANCE_BUCKETS; i++)
1048                INIT_HLIST_HEAD(&log->instance_table[i]);
1049        spin_lock_init(&log->instances_lock);
1050
1051#ifdef CONFIG_PROC_FS
1052        if (!proc_create("nfnetlink_log", 0440,
1053                         net->nf.proc_netfilter, &nful_file_ops))
1054                return -ENOMEM;
1055#endif
1056        return 0;
1057}
1058
1059static void __net_exit nfnl_log_net_exit(struct net *net)
1060{
1061#ifdef CONFIG_PROC_FS
1062        remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);
1063#endif
1064        nf_log_unset(net, &nfulnl_logger);
1065}
1066
1067static struct pernet_operations nfnl_log_net_ops = {
1068        .init   = nfnl_log_net_init,
1069        .exit   = nfnl_log_net_exit,
1070        .id     = &nfnl_log_net_id,
1071        .size   = sizeof(struct nfnl_log_net),
1072};
1073
1074static int __init nfnetlink_log_init(void)
1075{
1076        int status;
1077
1078        status = register_pernet_subsys(&nfnl_log_net_ops);
1079        if (status < 0) {
1080                pr_err("failed to register pernet ops\n");
1081                goto out;
1082        }
1083
1084        netlink_register_notifier(&nfulnl_rtnl_notifier);
1085        status = nfnetlink_subsys_register(&nfulnl_subsys);
1086        if (status < 0) {
1087                pr_err("failed to create netlink socket\n");
1088                goto cleanup_netlink_notifier;
1089        }
1090
1091        status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
1092        if (status < 0) {
1093                pr_err("failed to register logger\n");
1094                goto cleanup_subsys;
1095        }
1096
1097        return status;
1098
1099cleanup_subsys:
1100        nfnetlink_subsys_unregister(&nfulnl_subsys);
1101cleanup_netlink_notifier:
1102        netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1103        unregister_pernet_subsys(&nfnl_log_net_ops);
1104out:
1105        return status;
1106}
1107
1108static void __exit nfnetlink_log_fini(void)
1109{
1110        nf_log_unregister(&nfulnl_logger);
1111        nfnetlink_subsys_unregister(&nfulnl_subsys);
1112        netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1113        unregister_pernet_subsys(&nfnl_log_net_ops);
1114}
1115
1116MODULE_DESCRIPTION("netfilter userspace logging");
1117MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1118MODULE_LICENSE("GPL");
1119MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1120MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
1121MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
1122MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);
1123
1124module_init(nfnetlink_log_init);
1125module_exit(nfnetlink_log_fini);
1126