/*
 * br-json. Brigde list in JSON format.
 *
 * Based on Bridge Utils, see <http://www.linuxfoundation.org/en/Net:Bridge>
 *
 * Copyright (C) 2000 Lennert Buytenhek
 * Copyright (C) 2008 OpenRB.com
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <linux/if_bridge.h>

#define MAX_BRIDGES 32
#define MAX_PORTS  32

int print_ifnames(const char *);
int get_stp(const char *);

int br_socket_fd;

int main(void) {
  int i, num, first = 1;
  char brname[IFNAMSIZ];
  int brindices[MAX_BRIDGES];
  unsigned long brargs[3] = { BRCTL_GET_BRIDGES, (unsigned long) brindices, MAX_BRIDGES };

  if ((br_socket_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
    fprintf(stderr, "Cannot init: %s", strerror(errno));
    return errno;
  }

  num = ioctl(br_socket_fd, SIOCGIFBR, brargs);
  if (num < 0) {
    fprintf(stderr, "Get bridge indices failed: %s", strerror(errno));
    return -errno;
  }

  printf("{");

  for (i = 0; i < num; i++) {
    if (!if_indextoname(brindices[i], brname)) {
      fprintf(stderr, "Get find name for brindex %d failed", brindices[i]);
      return -errno;
    }

    printf("%s\"%s\": {\"stp\": %d, \"ifnames\": [", (first ? "" : ", "), brname, get_stp(brname) );
    print_ifnames(brname);
    printf("]}");
    first = 0;
  }

  printf("}");
  return 0;
}

int print_ifnames(const char *brname) {
  int i, err, first = 1;
  struct ifreq ifr;
  char ifname[IFNAMSIZ];
  int ifindices[MAX_PORTS];
  unsigned long args[4] = { BRCTL_GET_PORT_LIST, (unsigned long) ifindices, MAX_PORTS, 0 };

  memset(ifindices, 0, sizeof(ifindices));
  strncpy(ifr.ifr_name, brname, IFNAMSIZ);
  ifr.ifr_data = (char *) &args;

  err = ioctl(br_socket_fd, SIOCDEVPRIVATE, &ifr);
  if (err < 0) {
    fprintf(stderr, "List ports for bridge %s failed: %s", brname, strerror(errno));
    return -errno;
  }

  for (i = 0; i < MAX_PORTS; i++) {
    if (!ifindices[i] || !if_indextoname(ifindices[i], ifname)) {
      continue;
    }

    printf("%s\"%s\"", (first ? "" : ", "), ifname);
    first = 0;
  }

  return 0;
}

int get_stp(const char *bridge) {
  struct ifreq ifr;
  struct __bridge_info i;
  unsigned long args[4] = { BRCTL_GET_BRIDGE_INFO, (unsigned long) &i, 0, 0 };

  strncpy(ifr.ifr_name, bridge, IFNAMSIZ);
  ifr.ifr_data = (char *) &args;

  if (ioctl(br_socket_fd, SIOCDEVPRIVATE, &ifr) < 0) {
    fprintf(stderr, "Can't get stp info for %s", bridge);
    return 0;
  }

  return i.stp_enabled;
}