src/nf-monitor.c

   1 /*
   2  * src/nf-monitor.c     Monitor netfilter events
   3  *
   4  *      This library is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU Lesser General Public
   6  *      License as published by the Free Software Foundation version 2.1
   7  *      of the License.
   8  *
   9  * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
  10  * Copyright (c) 2007 Philip Craig <philipc@snapgear.com>
  11  * Copyright (c) 2007 Secure Computing Corporation
  12  */
  13
  14 #include <netlink/cli/utils.h>
  15 #include <netlink/netfilter/nfnl.h>
  16
  17 static void obj_input(struct nl_object *obj, void *arg)
  18 {
  19         struct nl_dump_params dp = {
  20                 .dp_type = NL_DUMP_STATS,
  21                 .dp_fd = stdout,
  22                 .dp_dump_msgtype = 1,
  23         };
  24
  25         nl_object_dump(obj, &dp);
  26 }
  27
  28 static int event_input(struct nl_msg *msg, void *arg)
  29 {
  30         if (nl_msg_parse(msg, &obj_input, NULL) < 0)
  31                 fprintf(stderr, "<<EVENT>> Unknown message type\n");
  32
  33         /* Exit nl_recvmsgs_def() and return to the main select() */
  34         return NL_STOP;
  35 }
  36
  37 int main(int argc, char *argv[])
  38 {
  39         struct nl_sock *sock;
  40         int err;
  41         int i, idx;
  42
  43         static const struct {
  44                 enum nfnetlink_groups gr_id;
  45                 const char* gr_name;
  46         } groups[] = {
  47                 { NFNLGRP_CONNTRACK_NEW, "ct-new" },
  48                 { NFNLGRP_CONNTRACK_UPDATE, "ct-update" },
  49                 { NFNLGRP_CONNTRACK_DESTROY, "ct-destroy" },
  50                 { NFNLGRP_NONE, NULL }
  51         };
  52
  53         sock = nl_cli_alloc_socket();
  54         nl_socket_disable_seq_check(sock);
  55         nl_socket_modify_cb(sock, NL_CB_VALID, NL_CB_CUSTOM, event_input, NULL);
  56
  57         if (argc > 1 && !strcasecmp(argv[1], "-h")) {
  58                 printf("Usage: nf-monitor [<groups>]\n");
  59
  60                 printf("Known groups:");
  61                 for (i = 0; groups[i].gr_id != NFNLGRP_NONE; i++)
  62                         printf(" %s", groups[i].gr_name);
  63                 printf("\n");
  64                 return 2;
  65         }
  66
  67         nl_cli_connect(sock, NETLINK_NETFILTER);
  68
  69         for (idx = 1; argc > idx; idx++) {
  70                 for (i = 0; groups[i].gr_id != NFNLGRP_NONE; i++) {
  71                         if (strcmp(argv[idx], groups[i].gr_name))
  72                                 continue;
  73
  74                         err = nl_socket_add_membership(sock, groups[i].gr_id);
  75                         if (err < 0)
  76                                 nl_cli_fatal(err,
  77                                              "Unable to add membership: %s",
  78                                              nl_geterror(err));
  79                         break;
  80                 }
  81
  82                 if (groups[i].gr_id == NFNLGRP_NONE)
  83                         nl_cli_fatal(NLE_OBJ_NOTFOUND, "Unknown group: \"%s\"",
  84                                      argv[idx]);
  85         }
  86
  87         while (1) {
  88                 fd_set rfds;
  89                 int fd, retval;
  90
  91                 fd = nl_socket_get_fd(sock);
  92
  93                 FD_ZERO(&rfds);
  94                 FD_SET(fd, &rfds);
  95                 /* wait for an incoming message on the netlink socket */
  96                 retval = select(fd+1, &rfds, NULL, NULL, NULL);
  97
  98                 if (retval) {
  99                         /* FD_ISSET(fd, &rfds) will be true */
 100                         nl_recvmsgs_default(sock);
 101                 }
 102         }
 103
 104         return 0;
 105 }