/* $Id: simple_client.c 216 2014-12-13 13:21:07Z roca $ */
/*
 * OpenFEC.org AL-FEC Library.
 * (c) Copyright 2009-2014 INRIA - All rights reserved
 * Contact: vincent.roca@inria.fr
 *
 * This software is governed by the CeCILL-C license under French law and
 * abiding by the rules of distribution of free software.  You can  use,
 * modify and/ or redistribute the software under the terms of the CeCILL-C
 * license as circulated by CEA, CNRS and INRIA at the following URL
 * "http://www.cecill.info".
 *
 * As a counterpart to the access to the source code and  rights to copy,
 * modify and redistribute granted by the license, users are provided only
 * with a limited warranty  and the software's author,  the holder of the
 * economic rights,  and the successive licensors  have only  limited
 * liability.
 *
 * In this respect, the user's attention is drawn to the risks associated
 * with loading,  using,  modifying and/or developing or reproducing the
 * software by the user in light of its specific status of free software,
 * that may mean  that it is complicated to manipulate,  and  that  also
 * therefore means  that it is reserved for developers  and  experienced
 * professionals having in-depth computer knowledge. Users are therefore
 * encouraged to load and test the software's suitability as regards their
 * requirements in conditions enabling the security of their systems and/or
 * data to be ensured and,  more generally, to use and operate it in the
 * same conditions as regards security.
 *
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL-C license and that you accept its terms.
 */

/* this is the decoder */
#define OF_USE_DECODER

#include "simple_client_server.h"

/*
 * Chose which decoding method to use... Both should be equivalent.
 */
#define USE_DECODE_WITH_NEW_SYMBOL

/* Prototypes */

/**
 * Opens and initializes a UDP socket, ready for receptions.
 */
static SOCKET init_socket(void);

/**
 * This function receives packets on the incoming UDP socket.
 * It allocates a buffer of size *len and updates the pkt/len arguments with
 * what has been actually received. It works in blocking mode the first time
 * it's called (as the client can be launched a few seconds before the server),
 * and after that in non blocking (i.e. polling) mode. If no packet is received
 * even after having waited a certain time (0.2s), it return OF_STATUS_FAILURE
 * to indicate that the sender probably stopped all transmissions.
 */
static of_status_t get_next_pkt(SOCKET so, void **pkt, INT32 *len);

/**
 * Dumps len32 32-bit words of a buffer (typically a symbol).
 */
static void dump_buffer_32(void *buf, UINT32 len32);

/*************************************************************************************************/

int main(int argc, char *argv[]) {
  of_codec_id_t codec_id;   /* identifier of the codec to use */
  of_session_t *ses = NULL; /* openfec codec instance identifier */
  of_parameters_t *params =
      NULL; /* structure used to initialize the openfec session */
  void **recvd_symbols_tab =
      NULL; /* table containing pointers to received symbols (no FPI here).
             * The allocated buffer start 4 bytes (i.e., sizeof(FPI)) before...
             */
  void **src_symbols_tab = NULL; /* table containing pointers to the source
                                    symbol buffers (no FPI here) */
  UINT32 symb_sz_32 =
      SYMBOL_SIZE / 4; /* symbol size in units of 32 bit words */
  UINT32 k;            /* number of source symbols in the block */
  UINT32 n; /* number of encoding symbols (i.e. source + repair) in the block */
  UINT32 esi; /* Encoding Symbol ID, used to identify each encoding symbol */
  SOCKET so =
      INVALID_SOCKET; /* UDP socket for server => client communications */
  void *pkt_with_fpi = NULL; /* pointer to a buffer containing the FPI followed
                                by the fixed size packet */
  fec_oti_t *fec_oti = NULL; /* FEC Object Transmission Information as received
                                from the server */
  INT32 len;                 /* len of the received packet */
  SOCKADDR_IN dst_host;
  UINT32 n_received =
      0;             /* number of symbols (source or repair) received so far */
  bool done = false; /* true as soon as all source symbols have been received or
                        recovered */
  UINT32 ret;

  /* First of all, initialize the UDP socket and wait for the FEC OTI to be
   * received. This is absolutely required to synchronize encoder and decoder.
   * We assume this first packet is NEVER lost otherwise decoding is not
   * possible. In practice the sender can transmit it periodically, or it is
   * sent through a separate reliable channel. */
  if ((so = init_socket()) == INVALID_SOCKET) {
    OF_PRINT_ERROR(("Error initializing socket!\n"))
    ret = -1;
    goto end;
  }
  len = sizeof(fec_oti_t); /* size of the expected packet */
  if ((ret = get_next_pkt(so, (void **)&fec_oti, &len)) != OF_STATUS_OK) {
    OF_PRINT_ERROR(("get_next_pkt failed (FEC OTI reception)\n"))
    ret = -1;
    goto end;
  }
  if (len != sizeof(fec_oti_t)) {
    OF_PRINT_ERROR(
        ("FEC OTI reception failed: bad size, expected %lu but received %d "
         "instead\n",
         sizeof(fec_oti_t), ret))
    ret = -1;
    goto end;
  }
  /* convert back to host endianess */
  codec_id = (of_codec_id_t)ntohl(fec_oti->codec_id);
  fec_oti->codec_id = ntohl(fec_oti->codec_id);
  k = fec_oti->k = ntohl(fec_oti->k);
  n = fec_oti->n = ntohl(fec_oti->n);

  printf("\nReceiving packets from %s/%d\n", DEST_IP, DEST_PORT);

  /* and check the correctness of data received */
  if (k > n || k > 40000 || n > 40000) {
    OF_PRINT_ERROR(
        ("Invalid FEC OTI received: k=%u or n=%u received are probably out of "
         "range\n",
         k, n))
    ret = -1;
    goto end;
  }
  /* now we know which codec the sender has used along with the codec
   * parameters, we can prepar the params structure accordingly */
  switch (codec_id) {
    case OF_CODEC_REED_SOLOMON_GF_2_M_STABLE: {
      /* fill in the code specific part of the of_..._parameters_t structure */
      of_rs_2_m_parameters_t *my_params;

      printf(
          "\nInitialize a Reed-Solomon over GF(2^m) codec instance, (n, "
          "k)=(%u, %u)...\n",
          n, k);
      if ((my_params = (of_rs_2_m_parameters_t *)calloc(
               1, sizeof(*my_params))) == NULL) {
        OF_PRINT_ERROR(("no memory for codec %d\n", codec_id))
        ret = -1;
        goto end;
      }
      my_params->m = 8;
      params = (of_parameters_t *)my_params;
      break;
    }

    case OF_CODEC_LDPC_STAIRCASE_STABLE: {
      /* fill in the code specific part of the of_..._parameters_t structure */
      of_ldpc_parameters_t *my_params;

      printf(
          "\nInitialize an LDPC-Staircase codec instance, (n, k)=(%u, %u)...\n",
          n, k);
      if ((my_params = (of_ldpc_parameters_t *)calloc(1, sizeof(*my_params))) ==
          NULL) {
        OF_PRINT_ERROR(("no memory for codec %d\n", codec_id))
        ret = -1;
        goto end;
      }
      my_params->prng_seed = rand();
      my_params->N1 = 7;
      params = (of_parameters_t *)my_params;
      break;
    }

    default:
      OF_PRINT_ERROR(
          ("Invalid FEC OTI received: codec_id=%u received is not valid\n",
           codec_id))
      ret = -1;
      goto end;
  }
  params->nb_source_symbols =
      k; /* fill in the generic part of the of_parameters_t structure */
  params->nb_repair_symbols = n - k;
  params->encoding_symbol_length = SYMBOL_SIZE;

  /* Open and initialize the openfec decoding session now that we know the
   * various parameters used by the sender/encoder... */
  if ((ret = of_create_codec_instance(&ses, codec_id, OF_DECODER, VERBOSITY)) !=
      OF_STATUS_OK) {
    OF_PRINT_ERROR(("of_create_codec_instance() failed\n"))
    ret = -1;
    goto end;
  }
  if (of_set_fec_parameters(ses, params) != OF_STATUS_OK) {
    OF_PRINT_ERROR(
        ("of_set_fec_parameters() failed for codec_id %d\n", codec_id))
    ret = -1;
    goto end;
  }

  printf("\nDecoding in progress. Waiting for new packets...\n");

  /* allocate a table for the received encoding symbol buffers. We'll update it
   * progressively */
  if (((recvd_symbols_tab = (void **)calloc(n, sizeof(void *))) == NULL) ||
      ((src_symbols_tab = (void **)calloc(n, sizeof(void *))) == NULL)) {
    OF_PRINT_ERROR(("no memory (calloc failed for enc_symbols_tab, n=%u)\n", n))
    ret = -1;
    goto end;
  }

  len = SYMBOL_SIZE + 4; /* size of the expected packet */
#ifdef USE_DECODE_WITH_NEW_SYMBOL
  /*
   * this is the standard method: submit each fresh symbol to the library ASAP,
   * upon reception (or later, but using the standard
   * of_decode_with_new_symbol() function).
   */
  while ((ret = get_next_pkt(so, &pkt_with_fpi, &len)) == OF_STATUS_OK) {
    /* OK, new packet received... */
    n_received++;
    esi = ntohl(*(UINT32 *)pkt_with_fpi);
    if (esi > n) /* a sanity check, in case... */
    {
      OF_PRINT_ERROR(("invalid esi=%u received in a packet's FPI\n", esi))
      ret = -1;
      goto end;
    }
    recvd_symbols_tab[esi] = (char *)pkt_with_fpi + 4; /* remember */
    printf("%05d => receiving symbol esi=%u (%s)\n", n_received, esi,
           (esi < k) ? "src" : "repair");
    if (of_decode_with_new_symbol(ses, (char *)pkt_with_fpi + 4, esi) ==
        OF_STATUS_ERROR) {
      OF_PRINT_ERROR(("of_decode_with_new_symbol() failed\n"))
      ret = -1;
      goto end;
    }
    /* check if completed in case we received k packets or more */
    if ((n_received >= k) && (of_is_decoding_complete(ses) == true)) {
      /* done, we recovered everything, no need to continue reception */
      done = true;
      break;
    }
    len = SYMBOL_SIZE +
          4; /* make sure len contains the size of the expected packet */
  }
#else
  /*
   * this is the alternative method: wait to receive all the symbols, then
   * submit them all to the library using the of_set_available_symbols()
   * function. In that case decoding will occur during the of_finish_decoding()
   * call.
   */
  while ((ret = get_next_pkt(so, &pkt_with_fpi, &len)) == OF_STATUS_OK) {
    /* OK, new packet received... */
    n_received++;
    esi = ntohl(*(UINT32 *)pkt_with_fpi);
    if (esi > n) /* a sanity check, in case... */
    {
      OF_PRINT_ERROR(("invalid esi=%u received in a packet's FPI\n", esi))
      ret = -1;
      goto end;
    }
    recvd_symbols_tab[esi] = (char *)pkt_with_fpi + 4; /* remember */
    printf("%05d => receiving symbol esi=%u (%s)\n", n_received, esi,
           (esi < k) ? "src" : "repair");
    len = SYMBOL_SIZE +
          4; /* make sure len contains the size of the expected packet */
  }
  /* now we received everything, submit them all to the codec if we received a
   * sufficiently high number of symbols (i.e. >= k) */
  if (n_received >= k &&
      (of_set_available_symbols(ses, recvd_symbols_tab) != OF_STATUS_OK)) {
    OF_PRINT_ERROR(("of_set_available_symbols() failed with error (%d)\n", ret))
    ret = -1;
    goto end;
  }
#endif
  if (!done && (ret == OF_STATUS_FAILURE) && (n_received >= k)) {
    /* there's no packet any more but we received at least k, and the use of
     * of_decode_with_new_symbol() didn't succedd to decode, so try with
     * of_finish_decoding. NB: this is useless with MDS codes (e.g.
     * Reed-Solomon), but it is essential with LDPC-Staircase as
     * of_decode_with_new_symbol performs ITerative decoding, whereas
     * of_finish_decoding performs ML decoding */
    ret = of_finish_decoding(ses);
    if (ret == OF_STATUS_ERROR || ret == OF_STATUS_FATAL_ERROR) {
      OF_PRINT_ERROR(("of_finish_decoding() failed with error (%d)\n", ret))
      ret = -1;
      goto end;
    } else if (ret == OF_STATUS_OK) {
      done = true;
    }
    /* else ret == OF_STATUS_FAILURE, meaning of_finish_decoding didn't manage
     * to recover all source symbols */
  }
  if (done) {
    /* finally, get a copy of the pointers to all the source symbols, those
     * received (that we already know) and those decoded. In case of received
     * symbols, the library does not change the pointers (same value). */
    if (of_get_source_symbols_tab(ses, src_symbols_tab) != OF_STATUS_OK) {
      OF_PRINT_ERROR(("of_get_source_symbols_tab() failed\n"))
      ret = -1;
      goto end;
    }
    printf("\nDone! All source symbols rebuilt after receiving %u packets\n",
           n_received);
    if (VERBOSITY > 1) {
      for (esi = 0; esi < k; esi++) {
        printf("src[%u]= ", esi);
        dump_buffer_32(src_symbols_tab[esi], 1);
      }
    }
  } else {
    printf(
        "\nFailed to recover all erased source symbols even after receiving %u "
        "packets\n",
        n_received);
  }

end:
  /* Cleanup everything... */
  if (so != INVALID_SOCKET) {
    close(so);
  }
  if (ses) {
    of_release_codec_instance(ses);
  }
  if (params) {
    free(params);
  }
  if (fec_oti) {
    free(fec_oti);
  }
  if (recvd_symbols_tab && src_symbols_tab) {
    for (esi = 0; esi < n; esi++) {
      if (recvd_symbols_tab[esi]) {
        /* this is a symbol received from the network, without its FPI that
         * starts 4 bytes before */
        free((char *)recvd_symbols_tab[esi] - 4);
      } else if (esi < k && src_symbols_tab[esi]) {
        /* this is a source symbol decoded by the openfec codec, so free it */
        ASSERT(recvd_symbols_tab[esi] == NULL);
        free(src_symbols_tab[esi]);
      }
    }
    free(recvd_symbols_tab);
    free(src_symbols_tab);
  }
  return ret;
}

/**
 * Opens and initializes a UDP socket, ready for receptions.
 */
static SOCKET init_socket() {
  SOCKET s;
  SOCKADDR_IN bindAddr;
  UINT32 sz = 1024 * 1024;

  if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == INVALID_SOCKET) {
    printf("Error: call to socket() failed\n");
    return INVALID_SOCKET;
  }
  bindAddr.sin_family = AF_INET;
  bindAddr.sin_port = htons((short)DEST_PORT);
  bindAddr.sin_addr.s_addr = INADDR_ANY;
  if (bind(s, (SOCKADDR *)&bindAddr, sizeof(bindAddr)) == SOCKET_ERROR) {
    printf("bind() failed. Port %d may be already in use\n", DEST_PORT);
    return INVALID_SOCKET;
  }
  /* increase the reception socket size as the default value may lead to a high
   * datagram loss rate */
  if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, &sz, sizeof(sz)) == -1) {
    printf("setsockopt() failed to set new UDP socket size to %u\n", sz);
    return INVALID_SOCKET;
  }
  return s;
}

/**
 * Receives packets on the incoming UDP socket.
 */
static of_status_t get_next_pkt(SOCKET so, void **pkt, INT32 *len) {
  static bool first_call = true;
  INT32 saved_len =
      *len; /* save it, in case we need to do several calls to recvfrom */

  if ((*pkt = malloc(saved_len)) == NULL) {
    OF_PRINT_ERROR(("no memory (malloc failed for p)\n"))
    return OF_STATUS_ERROR;
  }
  if (first_call) {
    /* the first time we must be in blocking mode since the flow may be launched
     * after a few seconds... */
    first_call = false;
    *len = recvfrom(so, *pkt, saved_len, 0, NULL, NULL);
    if (*len < 0) {
      /* this is an anormal error, exit */
      perror("recvfrom");
      OF_PRINT_ERROR(("recvfrom failed\n"))
      free(*pkt); /* don't forget to free it, otherwise it will leak */
      return OF_STATUS_ERROR;
    }
    /* set the non blocking mode for this socket now that the flow has been
     * launched */
    if (fcntl(so, F_SETFL, O_NONBLOCK) < 0) {
      OF_PRINT_ERROR(("ERROR, fcntl failed to set non blocking mode\n"))
      exit(-1);
    }
    if (VERBOSITY > 1)
      printf("%s: pkt received 0, len=%u\n", __FUNCTION__, *len);
    return OF_STATUS_OK;
  }
  /* otherwise we are in non-blocking mode... */
  *len = recvfrom(so, *pkt, saved_len, 0, NULL, NULL);
  if (*len > 0) {
    if (VERBOSITY > 1)
      printf("%s: pkt received 1, len=%u\n", __FUNCTION__, *len);
    return OF_STATUS_OK;
  } else if (errno == EAGAIN || errno == EWOULDBLOCK) {
    /* no packet available, sleep a little bit and retry */
    SLEEP(200); /* (in milliseconds) */
    *len = recvfrom(so, *pkt, saved_len, 0, NULL, NULL);
    if (*len > 0) {
      if (VERBOSITY > 1)
        printf("%s: pkt received 2, len=%u\n", __FUNCTION__, *len);
      return OF_STATUS_OK;
    } else {
      /* that's the end of the test, no packet available any more, we're sure of
       * that now... */
      if (VERBOSITY > 1)
        printf("%s: end of test, no packet after the sleep\n", __FUNCTION__);
      free(*pkt); /* don't forget to free it, otherwise it will leak */
      return OF_STATUS_FAILURE;
    }
  } else {
    /* this is an anormal error, exit */
    perror("recvfrom");
    OF_PRINT_ERROR(("ERROR, recvfrom failed\n"))
    free(*pkt); /* don't forget to free it, otherwise it will leak */
    return OF_STATUS_ERROR;
  }
  return OF_STATUS_ERROR; /* never called */
}

/**
 * Dumps len32 32-bit words of a buffer (typically a symbol).
 */
static void dump_buffer_32(void *buf, UINT32 len32) {
  UINT32 *ptr;
  UINT32 j = 0;

  printf("0x");
  for (ptr = (UINT32 *)buf; len32 > 0; len32--, ptr++) {
    /* convert to big endian format to be sure of byte order */
    printf("%08X", htonl(*ptr));
    if (++j == 10) {
      j = 0;
      printf("\n");
    }
  }
  printf("\n");
}