Broken SetLinkDNS() in c

update-dns.c

#include <stdio.h>
#include <stdlib.h>
#include <systemd/sd-bus.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>

int SetLinkDNSv4(sd_bus *bus, int if_index, struct in_addr ns1, struct in_addr ns2) {
  sd_bus_error error = SD_BUS_ERROR_NULL;
  sd_bus_message *m = NULL;
  int r;
  struct dns_address {
    int32_t sin_family;
    struct in_addr ip_addr;
  };
  struct dns_address addresses[2];


  addresses[0].sin_family = AF_INET;
  addresses[0].ip_addr = ns1;
  addresses[1].sin_family = AF_INET;
  addresses[1].ip_addr = ns2;

  r = sd_bus_call_method(bus,
                         "org.freedesktop.resolve1",           /* service to contact */
                         "/org/freedesktop/resolve1",          /* object path */
                         "org.freedesktop.resolve1.Manager",   /* interface name */
                         "SetLinkDNS",                         /* method name */
                         &error,                               /* object to return error in */
                         &m,                                   /* return message on success */
                         "ia(iay)",                            /* input signature */
                         if_index,
                         2,
                         addresses);
  if (r < 0) {
    fprintf(stderr, "Failed to issue method call: %s\n", error.message);
    goto finish;
  }

  /* Parse the response message */
  /*
  r = sd_bus_message_read(m, "o", &path);
  if (r < 0) {
    fprintf(stderr, "Failed to parse response message: %s\n", strerror(-r));
    goto finish;
  }
  */


finish:
  sd_bus_error_free(&error);
  sd_bus_message_unref(m);
}

int main(int argc, char *argv[]) {
  sd_bus *bus = NULL;
  int r;

  /* Connect to the system bus */
  r = sd_bus_open_system(&bus);
  if (r < 0) {
    fprintf(stderr, "Failed to connect to system bus: %s\n", strerror(-r));
    goto finish;
  }
  struct in_addr ns1;
  struct in_addr ns2;

  inet_aton("10.0.0.1", &ns1);
  inet_aton("10.0.0.2", &ns2);


  r = SetLinkDNSv4(bus, 16, ns1, ns2) ;

finish:
    sd_bus_unref(bus);

  return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}