netlink-notify/netlink-notify.c

   1 /*
   2  * (C) 2011 by Christian Hesse <mail@eworm.de>
   3  *
   4  * This software may be used and distributed according to the terms
   5  * of the GNU General Public License, incorporated herein by reference.
   6  */
   7
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11 #include <string.h>
  12
  13 #include <libnotify/notify.h>
  14
  15 #include <libmnl/libmnl.h>
  16 #include <linux/if.h>
  17 #include <linux/if_link.h>
  18 #include <linux/rtnetlink.h>
  19
  20 #define NOTIFICATION_TIMEOUT    10000
  21
  22 #define NOTIFICATION_TEXT       "Interface %s is %s."
  23 #define NOTIFICATION_TEXT_DEBUG "%s: Interface %s (index %d) is %s.\n"
  24
  25 unsigned int netlinksize = 0;
  26 NotifyNotification ** netlinkref;
  27 char * program;
  28
  29 static int data_attr_cb(const struct nlattr * attr, void * data) {
  30         const struct nlattr ** tb = data;
  31         int type = mnl_attr_get_type(attr);
  32
  33         if (mnl_attr_type_valid(attr, IFLA_MAX) < 0)
  34                 return MNL_CB_OK;
  35
  36         switch(type) {
  37                 case IFLA_MTU:
  38                         if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
  39                                 fprintf(stderr, "%s: Invalid netlink attribute.\n", program);
  40                                 return MNL_CB_ERROR;
  41                         }
  42                         break;
  43                 case IFLA_IFNAME:
  44                         if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
  45                                 fprintf(stderr, "%s: Invalid netlink attribute.\n", program);
  46                                 return MNL_CB_ERROR;
  47                         }
  48                         break;
  49         }
  50         tb[type] = attr;
  51         return MNL_CB_OK;
  52 }
  53
  54 static int data_cb(const struct nlmsghdr * nlh, void * data) {
  55         struct nlattr * tb[IFLA_MAX + 1] = {};
  56         struct ifinfomsg * ifm = mnl_nlmsg_get_payload(nlh);
  57
  58         char * notification = NULL;
  59         char * interface = NULL;
  60         NotifyNotification * netlink;
  61         unsigned int i;
  62
  63         gboolean res = FALSE;
  64         GError * error = NULL;
  65
  66         mnl_attr_parse(nlh, sizeof(* ifm), data_attr_cb, tb);
  67
  68         interface = (char *) mnl_attr_get_str(tb[IFLA_IFNAME]);
  69         notification = (char *) malloc(strlen(interface) + strlen(NOTIFICATION_TEXT));
  70         sprintf(notification, NOTIFICATION_TEXT, interface, (ifm->ifi_flags & IFF_RUNNING ? "up" : "down"));
  71         printf(NOTIFICATION_TEXT_DEBUG, program, interface, ifm->ifi_index, (ifm->ifi_flags & IFF_RUNNING ? "up" : "down"));
  72
  73         if (netlinksize < ifm->ifi_index) {
  74                 netlinkref = realloc(netlinkref, (ifm->ifi_index + 1) * sizeof(size_t));
  75                 for(i = netlinksize; i < ifm->ifi_index; i++) {
  76                         netlinkref[i + 1] = NULL;
  77                 }
  78                 netlinksize = ifm->ifi_index;
  79         }
  80
  81         if (netlinkref[ifm->ifi_index] == NULL) {
  82                 netlink = notify_notification_new("Netlink", notification, (ifm->ifi_flags & IFF_RUNNING ? "network-transmit-receive" : "network-error"));
  83                 netlinkref[ifm->ifi_index] = netlink;
  84         } else {
  85                 netlink = netlinkref[ifm->ifi_index];
  86                 notify_notification_update(netlink, "Netlink", notification, (ifm->ifi_flags & IFF_RUNNING ? "network-transmit-receive" : "network-error"));
  87         }
  88
  89         notify_notification_set_timeout(netlink, NOTIFICATION_TIMEOUT);
  90         notify_notification_set_category(netlink, "Netlink");
  91         notify_notification_set_urgency (netlink, NOTIFY_URGENCY_NORMAL);
  92
  93         while(!notify_notification_show(netlink, &error)) {
  94                 g_printerr("%s: Error \"%s\" while trying to show notification. Trying to reconnect.\n", program, error->message);
  95                 g_error_free(error);
  96                 error = NULL;
  97
  98                 notify_uninit();
  99                 if(!notify_init("Udev-Net-Notification")) {
 100                         fprintf(stderr, "%s: Can't create notify.\n", program);
 101                         exit(EXIT_FAILURE);
 102                 }
 103         }
 104
 105         free(notification);
 106
 107         return MNL_CB_OK;
 108 }
 109
 110 int main(int argc, char ** argv) {
 111         struct mnl_socket * nl;
 112         char buf[MNL_SOCKET_BUFFER_SIZE];
 113         int ret;
 114
 115         program = argv[0];
 116
 117         printf("%s: %s v%s (compiled: %s)\n", argv[0], PROGNAME, VERSION, DATE);
 118
 119         if(!notify_init("Netlink-Notification")) {
 120                 fprintf(stderr, "%s: Can't create notify.\n", argv[0]);
 121                 exit(EXIT_FAILURE);
 122         }
 123
 124         nl = mnl_socket_open(NETLINK_ROUTE);
 125         if (!nl) {
 126                 fprintf(stderr, "%s: Can't create netlink socket.\n", argv[0]);
 127                 exit(EXIT_FAILURE);
 128         }
 129
 130         if (mnl_socket_bind(nl, RTMGRP_LINK, MNL_SOCKET_AUTOPID) < 0) {
 131                 fprintf(stderr, "%s: Can't bind netlink socket.\n", argv[0]);
 132                 exit(EXIT_FAILURE);
 133         }
 134
 135         ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
 136         while (ret > 0) {
 137                 ret = mnl_cb_run(buf, ret, 0, 0, data_cb, NULL);
 138                 if (ret <= 0)
 139                         break;
 140                 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
 141         }
 142         if (ret == -1) {
 143                 fprintf(stderr, "%s: An error occured reading from netlink socket.\n", argv[0]);
 144                 exit(EXIT_FAILURE);
 145         }
 146
 147         mnl_socket_close(nl);
 148
 149         return 0;
 150 }