/*
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * network.c
 * Network code for libartnet
 * Copyright (C) 2004-2007 Simon Newton
 *
 */

#include <errno.h>

#ifndef WIN32
#include <sys/socket.h> // socket before net/if.h for mac
#include <net/if.h>
#include <sys/ioctl.h>
#else
typedef int socklen_t;
#include <winsock2.h>
#include <Lm.h>
#include <iphlpapi.h>
#endif

#include <unistd.h>

#include "private.h"

#ifdef HAVE_GETIFADDRS
 #ifdef HAVE_LINUX_IF_PACKET_H
   #define USE_GETIFADDRS
 #endif
#endif

#ifdef USE_GETIFADDRS
  #include <ifaddrs.h>
  #include <linux/types.h> // required by if_packet
  #include <linux/if_packet.h>
#endif


enum { INITIAL_IFACE_COUNT = 10 };
enum { IFACE_COUNT_INC = 5 };
enum { IFNAME_SIZE = 32 }; // 32 sounds a reasonable size

typedef struct iface_s {
  struct sockaddr_in ip_addr;
  struct sockaddr_in bcast_addr;
  int8_t hw_addr[ARTNET_MAC_SIZE];
  char   if_name[IFNAME_SIZE];
  struct iface_s *next;
} iface_t;

unsigned long LOOPBACK_IP = 0x7F000001;


/*
 * Free memory used by the iface's list
 * @param head a pointer to the head of the list
 */
static void free_ifaces(iface_t *head) {
  iface_t *ift, *ift_next;

  for (ift = head; ift != NULL; ift = ift_next) {
    ift_next = ift->next;
    free(ift);
  }
}


/*
 * Add a new interface to an interface list
 * @param head pointer to the head of the list
 * @param tail pointer to the end of the list
 * @return a new iface_t or void
 */
static iface_t *new_iface(iface_t **head, iface_t **tail) {
  iface_t *iface = (iface_t*) calloc(1, sizeof(iface_t));

  if (!iface) {
    artnet_error("%s: calloc error %s" , __FUNCTION__, strerror(errno));
    return NULL;
  }
  memset(iface, 0, sizeof(iface_t));

  if (!*head) {
    *head = *tail = iface;
  } else {
    (*tail)->next = iface;
    *tail = iface;
  }
  return iface;
}


#ifdef WIN32

/*
 * Set if_head to point to a list of iface_t structures which represent the
 * interfaces on this machine
 * @param ift_head the address of the pointer to the head of the list
 */
static int get_ifaces(iface_t **if_head) {
  iface_t *if_tail, *iface;
  PIP_ADAPTER_INFO pAdapter = NULL;
  PIP_ADAPTER_INFO pAdapterInfo;
  IP_ADDR_STRING *ipAddress;
  ULONG ulOutBufLen = sizeof(IP_ADAPTER_INFO);
  unsigned long net, mask;
  if_tail = NULL;

  while (1) {
    pAdapterInfo = (IP_ADAPTER_INFO*) malloc(ulOutBufLen);
    if (!pAdapterInfo) {
      artnet_error("Error allocating memory needed for GetAdaptersinfo");
      return ARTNET_EMEM;
    }

    DWORD status = GetAdaptersInfo(pAdapterInfo, &ulOutBufLen);
    if (status == NO_ERROR)
      break;

    free(pAdapterInfo);
    if (status != ERROR_BUFFER_OVERFLOW) {
      printf("GetAdaptersInfo failed with error: %d\n", (int) status);
      return ARTNET_ENET;
    }
  }

  for (pAdapter = pAdapterInfo;
       pAdapter && pAdapter < pAdapterInfo + ulOutBufLen;
       pAdapter = pAdapter->Next) {

    if(pAdapter->Type != MIB_IF_TYPE_ETHERNET)
      continue;

    for (ipAddress = &pAdapter->IpAddressList; ipAddress;
         ipAddress = ipAddress->Next) {

      net = inet_addr(ipAddress->IpAddress.String);
      if (net) {
        // Windows doesn't seem to have the notion of an interface being 'up'
        // so we check if this interface has an address assigned.
        iface = new_iface(if_head, &if_tail);
        if (!iface)
          continue;

        mask = inet_addr(ipAddress->IpMask.String);
        strncpy(iface->if_name, pAdapter->AdapterName, IFNAME_SIZE);
        memcpy(iface->hw_addr, pAdapter->Address, ARTNET_MAC_SIZE);
        iface->ip_addr.sin_addr.s_addr = net;
        iface->bcast_addr.sin_addr.s_addr = (
            (net & mask) | (0xFFFFFFFF ^ mask));
      }
    }
  }

  free(pAdapterInfo);
  return (ARTNET_EOK);
}

# else // not WIN32

#ifdef USE_GETIFADDRS

/*
 * Check if we are interested in this interface
 * @param ifa a pointer to a ifaddr struct
 */
static void add_iface_if_needed(iface_t **head, iface_t **tail,
                                struct ifaddrs *ifa) {

  // skip down, loopback and non inet interfaces
  if (!ifa || !ifa->ifa_addr) return;
  if (!(ifa->ifa_flags & IFF_UP)) return;
  if (ifa->ifa_flags & IFF_LOOPBACK) return;
  if (ifa->ifa_addr->sa_family != AF_INET) return;

  iface_t *iface = new_iface(head, tail);
  struct sockaddr_in *sin = (struct sockaddr_in*) ifa->ifa_addr;
  iface->ip_addr.sin_addr = sin->sin_addr;
  strncpy(iface->if_name, ifa->ifa_name, IFNAME_SIZE - 1);

  if (ifa->ifa_flags & IFF_BROADCAST) {
    sin = (struct sockaddr_in *) ifa->ifa_broadaddr;
    iface->bcast_addr.sin_addr = sin->sin_addr;
  }
}


/*
 * Set if_head to point to a list of iface_t structures which represent the
 * interfaces on this machine
 * @param ift_head the address of the pointer to the head of the list
 */
static int get_ifaces(iface_t **if_head) {
  struct ifaddrs *ifa_list, *ifa_iter;
  iface_t *if_tail, *if_iter;
  struct sockaddr_ll *sll;
  char *if_name, *cptr;
  *if_head = if_tail = NULL;

  if (getifaddrs(&ifa_list) != 0) {
    artnet_error("Error getting interfaces: %s", strerror(errno));
    return ARTNET_ENET;
  }

  for (ifa_iter = ifa_list; ifa_iter; ifa_iter = ifa_iter->ifa_next)
    add_iface_if_needed(if_head, &if_tail, ifa_iter);

  // Match up the interfaces with the corrosponding AF_PACKET interface
  // to fetch the hw addresses
  //
  // TODO: Will probably not work on OS X, it should
  //      return AF_LINK -type sockaddr
  for (if_iter = *if_head; if_iter; if_iter = if_iter->next) {
    if_name = strdup(if_iter->if_name);

    // if this is an alias, get mac of real interface
    if ((cptr = strchr(if_name, ':')))
      *cptr = 0;

    // Find corresponding iface_t structure
    for (ifa_iter = ifa_list; ifa_iter; ifa_iter = ifa_iter->ifa_next) {
      if ((!ifa_iter->ifa_addr) || ifa_iter->ifa_addr->sa_family != AF_PACKET)
        continue;

      if (strncmp(if_name, ifa_iter->ifa_name, IFNAME_SIZE) == 0) {
        // Found matching hw-address
        sll = (struct sockaddr_ll*) ifa_iter->ifa_addr;
        memcpy(if_iter->hw_addr, sll->sll_addr, ARTNET_MAC_SIZE);
        break;
      }
    }
    free(if_name);
  }
  freeifaddrs(ifa_list);
  return 0;
}

#else // no GETIFADDRS

/*
 * Set if_head to point to a list of iface_t structures which represent the
 * interfaces on this machine
 * @param ift_head the address of the pointer to the head of the list
 */
static int get_ifaces(iface_t **if_head) {
  struct ifconf ifc;
  struct ifreq *ifr, ifrcopy;
  struct sockaddr_in *sin;
  int len, lastlen, flags;
  char *buf, *ptr;
  iface_t *if_tail, *iface;
  int ret = ARTNET_EOK;
  int sd;

  *if_head = if_tail = NULL;

  // create socket to get iface config
  sd = socket(PF_INET, SOCK_DGRAM, 0);

  if (sd < 0) {
    artnet_error("%s : Could not create socket %s", __FUNCTION__, strerror(errno));
    ret = ARTNET_ENET;
    goto e_return;
  }

  // first use ioctl to get a listing of interfaces
  lastlen = 0;
  len = INITIAL_IFACE_COUNT * sizeof(struct ifreq);

  for (;;) {
    buf = malloc(len);

    if (buf == NULL) {
      artnet_error_malloc();
      ret = ARTNET_EMEM;
      goto e_free;
    }

    ifc.ifc_len = len;
    ifc.ifc_buf = buf;
    if (ioctl(sd, SIOCGIFCONF, &ifc) < 0) {
      if (errno != EINVAL || lastlen != 0) {
        artnet_error("%s : ioctl error %s", __FUNCTION__, strerror(errno));
        ret = ARTNET_ENET;
        goto e_free;
      }
    } else {
      if (ifc.ifc_len == lastlen)
        break;
      lastlen = ifc.ifc_len;
    }
    len += IFACE_COUNT_INC * sizeof(struct ifreq);
    free(buf);
  }

  // loop through each iface
  for (ptr = buf; ptr < buf + ifc.ifc_len;) {
    ifr = (struct ifreq*) ptr;

    // work out length here
#ifdef HAVE_SOCKADDR_SA_LEN
    len = max(sizeof(struct sockaddr), ifr->ifr_addr.sa_len);
#else
    switch (ifr->ifr_addr.sa_family) {
#ifdef  IPV6
      case AF_INET6:
        len = sizeof(struct sockaddr_in6);
        break;
#endif
      case AF_INET:
      default:
        len = sizeof(SA);
        break;
    }
#endif

    ptr += sizeof(ifr->ifr_name) + len;

    // look for AF_INET interfaces
    if (ifr->ifr_addr.sa_family == AF_INET) {
      ifrcopy = *ifr;
      if (ioctl(sd, SIOCGIFFLAGS, &ifrcopy) < 0) {
        artnet_error("%s : ioctl error %s" , __FUNCTION__, strerror(errno));
        ret = ARTNET_ENET;
        goto e_free_list;
      }

      flags = ifrcopy.ifr_flags;
      if ((flags & IFF_UP) == 0)
        continue; //skip down interfaces

      if ((flags & IFF_LOOPBACK))
        continue; //skip lookback

      iface = new_iface(if_head, &if_tail);
      if (!iface)
        goto e_free_list;

      sin = (struct sockaddr_in *) &ifr->ifr_addr;
      iface->ip_addr.sin_addr = sin->sin_addr;

      // fetch bcast address
#ifdef SIOCGIFBRDADDR
      if (flags & IFF_BROADCAST) {
        if (ioctl(sd, SIOCGIFBRDADDR, &ifrcopy) < 0) {
          artnet_error("%s : ioctl error %s" , __FUNCTION__, strerror(errno));
          ret = ARTNET_ENET;
          goto e_free_list;
        }

        sin = (struct sockaddr_in *) &ifrcopy.ifr_broadaddr;
        iface->bcast_addr.sin_addr = sin->sin_addr;
      }
#endif
      // fetch hardware address
#ifdef SIOCGIFHWADDR
      if (flags & SIOCGIFHWADDR) {
        if (ioctl(sd, SIOCGIFHWADDR, &ifrcopy) < 0) {
          artnet_error("%s : ioctl error %s", __FUNCTION__, strerror(errno));
          ret = ARTNET_ENET;
          goto e_free_list;
        }
        memcpy(&iface->hw_addr, ifrcopy.ifr_hwaddr.sa_data, ARTNET_MAC_SIZE);
      }
#endif

    /* ok, if that all failed we should prob try and use sysctl to work out the bcast
     * and hware addresses
     * i'll leave that for another day
     */
    }
  }
  free(buf);
  return ARTNET_EOK;

e_free_list:
  free_ifaces(*if_head);
e_free:
  free(buf);
  close(sd);
e_return:
  return ret;
}

#endif // GETIFADDRS
#endif // not WIN32


/*
 * Scan for interfaces, and work out which one the user wanted to use.
 */
int artnet_net_init(node n, const char *preferred_ip) {
  iface_t *ift, *ift_head = NULL;
  struct in_addr wanted_ip;

  int found = FALSE;
  int i;
  int ret = ARTNET_EOK;

  if ((ret = get_ifaces(&ift_head)))
    goto e_return;

  if (n->state.verbose) {
    printf("#### INTERFACES FOUND ####\n");
    for (ift = ift_head; ift != NULL; ift = ift->next) {
      printf("IP: %s\n", inet_ntoa(ift->ip_addr.sin_addr));
      printf("  bcast: %s\n" , inet_ntoa(ift->bcast_addr.sin_addr));
      printf("  hwaddr: ");
      for (i = 0; i < ARTNET_MAC_SIZE; i++) {
        if (i)
          printf(":");
        printf("%02x", (uint8_t) ift->hw_addr[i]);
      }
      printf("\n");
    }
    printf("#########################\n");
  }

  if (preferred_ip) {
    // search through list of interfaces for one with the correct address
    ret = artnet_net_inet_aton(preferred_ip, &wanted_ip);
    if (ret)
      goto e_cleanup;

    for (ift = ift_head; ift != NULL; ift = ift->next) {
      if (ift->ip_addr.sin_addr.s_addr == wanted_ip.s_addr) {
        found = TRUE;
        n->state.ip_addr = ift->ip_addr.sin_addr;
        n->state.bcast_addr = ift->bcast_addr.sin_addr;
        memcpy(&n->state.hw_addr, &ift->hw_addr, ARTNET_MAC_SIZE);
        break;
      }
    }
    if (!found) {
      artnet_error("Cannot find ip %s", preferred_ip);
      ret = ARTNET_ENET;
      goto e_cleanup;
    }
  } else {
    if (ift_head) {
      // pick first address
      // copy ip address, bcast address and hardware address
      n->state.ip_addr = ift_head->ip_addr.sin_addr;
      n->state.bcast_addr = ift_head->bcast_addr.sin_addr;
      memcpy(&n->state.hw_addr, &ift_head->hw_addr, ARTNET_MAC_SIZE);
    } else {
      artnet_error("No interfaces found!");
      ret = ARTNET_ENET;
    }
  }

e_cleanup:
  free_ifaces(ift_head);
e_return :
  return ret;
}


/*
 * Start listening on the socket
 */
int artnet_net_start(node n) {
  int sock;
  struct sockaddr_in servAddr;
  int true_flag = TRUE;
  node tmp;

  // only attempt to bind if we are the group master
  if (n->peering.master == TRUE) {

#ifdef WIN32
    // check winsock version
    WSADATA wsaData;
    WORD wVersionRequested = MAKEWORD(2, 2);
    if (WSAStartup(wVersionRequested, &wsaData) != 0)
      return (-1);
    if (wsaData.wVersion != wVersionRequested)
      return (-2);
#endif

    // create socket
    sock = socket(PF_INET, SOCK_DGRAM, 0);

    if (sock < 0) {
      artnet_error("Could not create socket %s", artnet_net_last_error());
      return ARTNET_ENET;
    }

    memset(&servAddr, 0x00, sizeof(servAddr));
    servAddr.sin_family = AF_INET;
    servAddr.sin_port = htons(ARTNET_PORT);
    servAddr.sin_addr.s_addr = htonl(INADDR_ANY);

    if (n->state.verbose)
      printf("Binding to %s \n", inet_ntoa(servAddr.sin_addr));

    // bind sockets
    if (bind(sock, (SA *) &servAddr, sizeof(servAddr)) == -1) {
      artnet_error("Failed to bind to socket %s", artnet_net_last_error());
      artnet_net_close(sock);
      return ARTNET_ENET;
    }

    // allow bcasting
    if (setsockopt(sock,
                   SOL_SOCKET,
                   SO_BROADCAST,
                   (char*) &true_flag, // char* for win32
                   sizeof(int)) == -1) {
      artnet_error("Failed to bind to socket %s", artnet_net_last_error());
      artnet_net_close(sock);
      return ARTNET_ENET;
    }

#ifdef WIN32
    // ### LH - 22.08.2008
    // make it possible to reuse port, if SO_REUSEADDR
    // exists on operating system

    // NEVER USE SO_EXCLUSIVEADDRUSE, as that freezes the application
    // on WinXP, if port is in use !
    if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *) &true_flag,
        sizeof(true_flag)) < 0) {

      artnet_error("Set reuse failed", artnet_net_last_error());
      artnet_net_close(sock);
      return ARTNET_ENET;
    }

    u_long true = 1;
    if (SOCKET_ERROR == ioctlsocket(sock, FIONBIO, &true)) {

      artnet_error("ioctlsocket", artnet_net_last_error());
      artnet_net_close(sock);
      return ARTNET_ENET;
    }
#endif

    n->sd = sock;
    // Propagate the socket to all our peers
    for (tmp = n->peering.peer; tmp && tmp != n; tmp = tmp->peering.peer)
      tmp->sd = sock;
  }
  return ARTNET_EOK;
}


/*
 * Receive a packet.
 */
int artnet_net_recv(node n, artnet_packet p, int delay) {
  ssize_t len;
  struct sockaddr_in cliAddr;
  socklen_t cliLen = sizeof(cliAddr);
  fd_set rset;
  struct timeval tv;
  int maxfdp1 = n->sd + 1;

  FD_ZERO(&rset);
  FD_SET((unsigned int) n->sd, &rset);

  tv.tv_usec = 0;
  tv.tv_sec = delay;
  p->length = 0;

  switch (select(maxfdp1, &rset, NULL, NULL, &tv)) {
    case 0:
      // timeout
      return RECV_NO_DATA;
      break;
    case -1:
      if ( errno != EINTR) {
        artnet_error("Select error %s", artnet_net_last_error());
        return ARTNET_ENET;
      }
      return ARTNET_EOK;
      break;
    default:
      break;
  }

  // need a check here for the amount of data read
  // should prob allow an extra byte after data, and pass the size as sizeof(Data) +1
  // then check the size read and if equal to size(data)+1 we have an error
  len = recvfrom(n->sd,
                 (char*) &(p->data), // char* for win32
                 sizeof(p->data),
                 0,
                 (SA*) &cliAddr,
                 &cliLen);
  if (len < 0) {
    artnet_error("Recvfrom error %s", artnet_net_last_error());
    return ARTNET_ENET;
  }

  if (cliAddr.sin_addr.s_addr == n->state.ip_addr.s_addr ||
      ntohl(cliAddr.sin_addr.s_addr) == LOOPBACK_IP) {
    p->length = 0;
    return ARTNET_EOK;
  }

  p->length = len;
  memcpy(&(p->from), &cliAddr.sin_addr, sizeof(struct in_addr));
  // should set to in here if we need it
  return ARTNET_EOK;
}


/*
 * Send a packet.
 */
int artnet_net_send(node n, artnet_packet p) {
  struct sockaddr_in addr;
  int ret;

  if (n->state.mode != ARTNET_ON)
    return ARTNET_EACTION;

  addr.sin_family = AF_INET;
  addr.sin_port = htons(ARTNET_PORT);
  addr.sin_addr = p->to;
  p->from = n->state.ip_addr;

  if (n->state.verbose)
    printf("sending to %s\n" , inet_ntoa(addr.sin_addr));

  ret = sendto(n->sd,
               (char*) &p->data, // char* required for win32
               p->length,
               0,
               (SA*) &addr,
               sizeof(addr));
  if (ret == -1) {
    artnet_error("Sendto failed: %s", artnet_net_last_error());
    n->state.report_code = ARTNET_RCUDPFAIL;
    return ARTNET_ENET;

  } else if (p->length != ret) {
    artnet_error("failed to send full datagram");
    n->state.report_code = ARTNET_RCSOCKETWR1;
    return ARTNET_ENET;
  }

  if (n->callbacks.send.fh) {
    get_type(p);
    n->callbacks.send.fh(n, p, n->callbacks.send.data);
  }
  return ARTNET_EOK;
}


/*
int artnet_net_reprogram(node n) {
  iface_t *ift_head, *ift;
  int i;

  ift_head = get_ifaces(n->sd[0]);

  for (ift = ift_head;ift != NULL; ift = ift->next ) {
    printf("IP: %s\n", inet_ntoa(ift->ip_addr.sin_addr) );
    printf("  bcast: %s\n" , inet_ntoa(ift->bcast_addr.sin_addr) );
    printf("  hwaddr: ");
      for(i = 0; i < 6; i++ ) {
        printf("%hhx:", ift->hw_addr[i] );
      }
    printf("\n");
  }

  free_ifaces(ift_head);

}*/


int artnet_net_set_fdset(node n, fd_set *fdset) {
  FD_SET((unsigned int) n->sd, fdset);
  return ARTNET_EOK;
}


/*
 * Close a socket
 */
int artnet_net_close(int sock) {
#ifdef WIN32
  shutdown(sock, SD_BOTH);
  closesocket(sock);
  //WSACancelBlockingCall();
  WSACleanup();
#else
  if (close(sock)) {
    artnet_error(artnet_net_last_error());
    return ARTNET_ENET;
  }
#endif
  return ARTNET_EOK;
}


/*
 * Convert a string to an in_addr
 */
int artnet_net_inet_aton(const char *ip_address, struct in_addr *address) {
#ifdef HAVE_INET_ATON
  if (!inet_aton(ip_address, address)) {
#else
  in_addr_t *addr = (in_addr_t*) address;
  if ((*addr = inet_addr(ip_address)) == INADDR_NONE) {
#endif
    artnet_error("IP conversion from %s failed", ip_address);
    return ARTNET_EARG;
  }
  return ARTNET_EOK;
}


/*
 *
 */
const char *artnet_net_last_error() {
#ifdef WIN32
  static char error_str[10];
  int error = WSAGetLastError();
  snprintf(error_str, sizeof(error_str), "%d", error);
  return error_str;
#else
  return strerror(errno);
#endif
}