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) 2003-2006 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 "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_handle *nlh;
  40         int err = 1;
  41         int i, idx;
  42
  43         static const struct {
  44                 enum nfnetlink_groups gr_id;
  45                 const char* gr_name;
  46         } known_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         if (nltool_init(argc, argv) < 0)
  54                 return -1;
  55
  56         nlh = nltool_alloc_handle();
  57         if (nlh == NULL)
  58                 return -1;
  59
  60         nl_disable_sequence_check(nlh);
  61
  62         nl_socket_modify_cb(nlh, NL_CB_VALID, NL_CB_CUSTOM, event_input, NULL);
  63
  64         if (argc > 1 && !strcasecmp(argv[1], "-h")) {
  65                 printf("Usage: nf-monitor [<groups>]\n");
  66
  67                 printf("Known groups:");
  68                 for (i = 0; known_groups[i].gr_id != NFNLGRP_NONE; i++)
  69                         printf(" %s", known_groups[i].gr_name);
  70                 printf("\n");
  71                 return 2;
  72         }
  73
  74         if (nfnl_connect(nlh) < 0) {
  75                 fprintf(stderr, "%s\n", nl_geterror());
  76                 goto errout;
  77         }
  78
  79         for (idx = 1; argc > idx; idx++) {
  80                 for (i = 0; known_groups[i].gr_id != NFNLGRP_NONE; i++) {
  81                         if (!strcmp(argv[idx], known_groups[i].gr_name)) {
  82
  83                                 if (nl_socket_add_membership(nlh, known_groups[i].gr_id) < 0) {
  84                                         fprintf(stderr, "%s: %s\n", argv[idx], nl_geterror());
  85                                         goto errout;
  86                                 }
  87
  88                                 break;
  89                         }
  90                 }
  91                 if (known_groups[i].gr_id == NFNLGRP_NONE)
  92                         fprintf(stderr, "Warning: Unknown group: %s\n", argv[idx]);
  93         }
  94
  95         while (1) {
  96                 fd_set rfds;
  97                 int fd, retval;
  98
  99                 fd = nl_socket_get_fd(nlh);
 100
 101                 FD_ZERO(&rfds);
 102                 FD_SET(fd, &rfds);
 103                 /* wait for an incoming message on the netlink socket */
 104                 retval = select(fd+1, &rfds, NULL, NULL, NULL);
 105
 106                 if (retval) {
 107                         /* FD_ISSET(fd, &rfds) will be true */
 108                         nl_recvmsgs_default(nlh);
 109                 }
 110         }
 111
 112         nl_close(nlh);
 113 errout:
 114         return err;
 115 }