networkconfig.c

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/*******************************************************************************
 * Copyright (c) 2018, Rockwell Automation, Inc.
 * All rights reserved.
 *
 ******************************************************************************/
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

#include "ciptcpipinterface.h"
#include "networkconfig.h"
#include "cipcommon.h"
#include "ciperror.h"
#include "trace.h"
#include "opener_api.h"

#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/if.h>
#include <net/if.h>
#include <netinet/in.h>

#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <arpa/inet.h>
#include <unistd.h>

#define LOOPBACK_BINARY 0x7f000001

void ConfigureMacAddress(const char *interface) {
  struct ifreq ifr;
  size_t if_name_len = strlen(interface);
  if(if_name_len < sizeof(ifr.ifr_name) ) {
    memcpy(ifr.ifr_name, interface, if_name_len);
    ifr.ifr_name[if_name_len] = 0;
  }
  else{
    OPENER_TRACE_INFO("interface name is too long");
  }

  int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);

  if(ioctl(fd, SIOCGIFHWADDR, &ifr) == 0) {
    memcpy(&(g_ethernet_link.physical_address), &ifr.ifr_hwaddr.sa_data,
           sizeof(g_ethernet_link.physical_address) );
  }
  CloseSocket(fd);
}

EipStatus ConfigureNetworkInterface(const char *const network_interface) {

  struct ifreq ifr;
  size_t if_name_len = strlen(network_interface);
  if(if_name_len < sizeof(ifr.ifr_name) ) {
    memcpy(ifr.ifr_name, network_interface, if_name_len);
    ifr.ifr_name[if_name_len] = 0;
  }
  else{
    OPENER_TRACE_INFO("interface name is too long\n");
  }

  int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
  int ipaddr = 0;
  int netaddr = 0;
  if(ioctl(fd, SIOCGIFADDR, &ifr) == 0) {
    ipaddr = ( (struct sockaddr_in *) &ifr.ifr_addr )->sin_addr.s_addr;
  }
  else{
    return kEipStatusError;
  }

  if(ioctl(fd, SIOCGIFNETMASK, &ifr) == 0) {
    netaddr = ( (struct sockaddr_in *) &ifr.ifr_netmask )->sin_addr.s_addr;
  }
  else{
    return kEipStatusError;
  }

  interface_configuration_.ip_address = ipaddr;
  interface_configuration_.network_mask = netaddr;

  char route_location[] = "/proc/net/route";

  FILE *file_handle = fopen(route_location, "r");
  char file_buffer[100] = { 0 };
  char *gateway_string = NULL;
  CipUdint gateway = 0;

  if(file_handle) {
    char *needle_start = NULL;
    while(NULL ==
          (needle_start =
             strstr(file_buffer,
                    network_interface) ) &&
          fgets(file_buffer, sizeof(file_buffer), file_handle) ) {
    }

    if(NULL != needle_start) {
      char *strtok_save = NULL;
      strtok_r(needle_start, " \t", &strtok_save);
      strtok_r(needle_start, " \t", &strtok_save);
      gateway_string = strtok_r(needle_start, "\t", &strtok_save);
    }
    else{
      OPENER_TRACE_ERR("network interface: %s not found", network_interface);
      fclose(file_handle);
      exit(1);
    }
  }

  if(inet_pton(AF_INET, gateway_string, &gateway) == 1) {
    if(LOOPBACK_BINARY != gateway) {
      interface_configuration_.gateway = gateway;
    }
    else{
      interface_configuration_.gateway = 0;
    }
  }
  else{
    interface_configuration_.gateway = 0;
  }

  /* calculate the CIP multicast address. The multicast address is calculated, not input*/
  EipUint32 host_id = ntohl(interface_configuration_.ip_address) & ~ntohl(
    interface_configuration_.network_mask);                                                                       /* see CIP spec 3-5.3 for multicast address algorithm*/
  host_id -= 1;
  host_id &= 0x3ff;

  g_multicast_configuration.starting_multicast_address =
    htonl(ntohl(inet_addr("239.192.1.0") ) + (host_id << 5) );

  CloseSocket(fd);
  fclose(file_handle);

  return kEipStatusOk;
}

void ConfigureDomainName() {
  char resolv_conf_file[] = "/etc/resolv.conf";
  FILE *file_handle = fopen(resolv_conf_file, "r");
  char *file_buffer = NULL;
  size_t file_length;
  char *domain_name_string = NULL;
  char *dns1_string = NULL;
  char *dns2_string = NULL;

  if(file_handle) {
    fseek(file_handle, 0, SEEK_END);
    file_length = ftell(file_handle);
    fseek(file_handle, 0, SEEK_SET);
    file_buffer = malloc(file_length);
    if(file_buffer) {
      fread(file_buffer, 1, file_length, file_handle);
      fclose(file_handle);
    }
    else{
      OPENER_TRACE_ERR("Could not allocate memory for reading file %s\n",
                       resolv_conf_file);
      fclose(file_handle);
      exit(1);
    }
  } else {
    OPENER_TRACE_ERR("Could not open file %s\n", resolv_conf_file);
    exit(1);
  }

  if(strstr(file_buffer, "domain") ) {
    char *strtok_save = NULL;
    strtok_r(file_buffer, " ", &strtok_save);
    domain_name_string = strtok_r(file_buffer, "\n", &strtok_save);

    if(NULL != interface_configuration_.domain_name.string) {
      /* if the string is already set to a value we have to free the resources
       * before we can set the new value in order to avoid memory leaks.
       */
      CipFree(interface_configuration_.domain_name.string);
    }
    interface_configuration_.domain_name.length = strlen(domain_name_string);

    if(interface_configuration_.domain_name.length) {
      interface_configuration_.domain_name.string = (EipByte *) CipCalloc(
        interface_configuration_.domain_name.length + 1,
        sizeof(EipByte) );
      snprintf(interface_configuration_.domain_name.string,
               (interface_configuration_.domain_name.length + 1) *
               sizeof(EipByte),
               "%s",
               domain_name_string);
    }
    else{
      interface_configuration_.domain_name.string = NULL;
    }
  }

  if(strstr(file_buffer, "nameserver") ) {
    char *strtok_save = NULL;
    strtok_r(file_buffer, " ", &strtok_save);
    dns1_string = strtok_r(NULL, "\n", &strtok_save);

    inet_pton(AF_INET, dns1_string, &interface_configuration_.name_server);
  }

  if(strstr(file_buffer, "nameserver ") ) {
    char *strtok_save = NULL;
    strtok_r(file_buffer, " ", &strtok_save);
    dns2_string = strtok_r(file_buffer, "\n", &strtok_save);

    inet_pton(AF_INET, dns2_string, &interface_configuration_.name_server_2);
  }

  free(file_buffer);
}

void ConfigureHostName() {
  char name[1024] = { 0 };
  gethostname(name, sizeof(name) );

  if(NULL != hostname_.string) {
    /* if the string is already set to a value we have to free the resources
     * before we can set the new value in order to avoid memory leaks.
     */
    CipFree(hostname_.string);
  }
  hostname_.length = strlen(name);
  if(hostname_.length) {
    hostname_.string =
      (EipByte *) CipCalloc(hostname_.length + 1, sizeof(EipByte) );
    snprintf( (char *)hostname_.string,
              (hostname_.length + 1) * sizeof(EipByte), "%s", name );
  }
  else{
    hostname_.string = NULL;
  }
}