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nf-queue.c

/*
 * src/nf-log.c     Monitor netfilter queue events
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation version 2.1
 *    of the License.
 *
 * Copyright (c) 2007, 2008 Patrick McHardy <kaber@trash.net>
 */


#include <netlink/cli/utils.h>
#include <netlink/cli/link.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink_queue.h>
#include <netlink/netfilter/nfnl.h>
#include <netlink/netfilter/queue.h>
#include <netlink/netfilter/queue_msg.h>

static struct nl_sock *nf_sock;

static struct nfnl_queue *alloc_queue(void)
{
      struct nfnl_queue *queue;

      queue = nfnl_queue_alloc();
      if (!queue)
            nl_cli_fatal(ENOMEM, "Unable to allocate queue object");

      return queue;
}


static void obj_input(struct nl_object *obj, void *arg)
{
      struct nfnl_queue_msg *msg = (struct nfnl_queue_msg *) obj;
      struct nl_dump_params dp = {
            .dp_type = NL_DUMP_STATS,
            .dp_fd = stdout,
            .dp_dump_msgtype = 1,
      };

      nfnl_queue_msg_set_verdict(msg, NF_ACCEPT);
      nl_object_dump(obj, &dp);
      nfnl_queue_msg_send_verdict(nf_sock, msg);
}

static int event_input(struct nl_msg *msg, void *arg)
{
      if (nl_msg_parse(msg, &obj_input, NULL) < 0)
            fprintf(stderr, "<<EVENT>> Unknown message type\n");

      /* Exit nl_recvmsgs_def() and return to the main select() */
      return NL_STOP;
}

int main(int argc, char *argv[])
{
      struct nl_sock *rt_sock;
      struct nl_cache *link_cache;
      struct nfnl_queue *queue;
      enum nfnl_queue_copy_mode copy_mode;
      uint32_t copy_range;
      int err = 1;
      int family;

      nf_sock = nfnl_queue_socket_alloc();
      if (nf_sock == NULL)
            nl_cli_fatal(ENOBUFS, "Unable to allocate netlink socket");

      nl_socket_disable_seq_check(nf_sock);
      nl_socket_modify_cb(nf_sock, NL_CB_VALID, NL_CB_CUSTOM, event_input, NULL);

      if ((argc > 1 && !strcasecmp(argv[1], "-h")) || argc < 3) {
            printf("Usage: nf-queue family group [ copy_mode ] "
                   "[ copy_range ]\n");
            return 2;
      }

      nl_cli_connect(nf_sock, NETLINK_NETFILTER);

      if ((family = nl_str2af(argv[1])) == AF_UNSPEC)
            nl_cli_fatal(NLE_INVAL, "Unknown family \"%s\"", argv[1]);

      nfnl_queue_pf_unbind(nf_sock, family);
      if ((err = nfnl_queue_pf_bind(nf_sock, family)) < 0)
            nl_cli_fatal(err, "Unable to bind logger: %s",
                       nl_geterror(err));

      queue = alloc_queue();
      nfnl_queue_set_group(queue, atoi(argv[2]));

      copy_mode = NFNL_QUEUE_COPY_PACKET;
      if (argc > 3) {
            copy_mode = nfnl_queue_str2copy_mode(argv[3]);
            if (copy_mode < 0)
                  nl_cli_fatal(copy_mode,
                             "Unable to parse copy mode \"%s\": %s",
                             argv[3], nl_geterror(copy_mode));
      }
      nfnl_queue_set_copy_mode(queue, copy_mode);

      copy_range = 0xFFFF;
      if (argc > 4)
            copy_range = atoi(argv[4]);
      nfnl_queue_set_copy_range(queue, copy_range);

      if ((err = nfnl_queue_create(nf_sock, queue)) < 0)
            nl_cli_fatal(err, "Unable to bind queue: %s", nl_geterror(err));

      rt_sock = nl_cli_alloc_socket();
      nl_cli_connect(rt_sock, NETLINK_ROUTE);
      link_cache = nl_cli_link_alloc_cache(rt_sock);

      while (1) {
            fd_set rfds;
            int nffd, rtfd, maxfd, retval;

            FD_ZERO(&rfds);

            maxfd = nffd = nl_socket_get_fd(nf_sock);
            FD_SET(nffd, &rfds);

            rtfd = nl_socket_get_fd(rt_sock);
            FD_SET(rtfd, &rfds);
            if (maxfd < rtfd)
                  maxfd = rtfd;

            /* wait for an incoming message on the netlink socket */
            retval = select(maxfd+1, &rfds, NULL, NULL, NULL);

            if (retval) {
                  if (FD_ISSET(nffd, &rfds))
                        nl_recvmsgs_default(nf_sock);
                  if (FD_ISSET(rtfd, &rfds))
                        nl_recvmsgs_default(rt_sock);
            }
      }

      return 0;
}

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