/* $Id: simple_server.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 encoder */
#define OF_USE_ENCODER

#include "simple_client_server.h"

/* Prototypes */

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

/**
 * Shuffles the array randomly.
 */
static void randomize_array(UINT32 **array, UINT32 arrayLen);

/**
 * 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 **enc_symbols_tab = NULL; /* table containing pointers to the encoding
                                    (i.e. source + repair) symbols buffers */
  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 */
  UINT32 i;
  UINT32 *rand_order = NULL; /* table used to determine a random transmission
                              * order. This randomization process is essential
                              * for LDPC-Staircase optimal performance */
  SOCKET so =
      INVALID_SOCKET; /* UDP socket for server => client communications */
  char *pkt_with_fpi = NULL; /* buffer containing a fixed size packet plus a
                                header consisting only of the FPI */
  fec_oti_t
      fec_oti; /* FEC Object Transmission Information as sent to the client */
  INT32 lost_after_index = -1; /* all the packets to send after this index are
                                  considered as lost during transmission */
  SOCKADDR_IN dst_host;
  UINT32 ret = -1;

  if (argc == 1) {
    /* k value is ommited, so use default */
    k = DEFAULT_K;
  } else {
    k = atoi(argv[1]);
  }
  n = (UINT32)floor((double)k / (double)CODE_RATE);
  /* Choose which codec is the most appropriate. If small enough, choose
   * Reed-Solomon (with m=8), otherwise LDPC-Staircase. Then finish the openfec
   * session initialization accordingly */
  if (n <= 255) {
    /* 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);
    codec_id = OF_CODEC_REED_SOLOMON_GF_2_M_STABLE;
    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;
  } else {
    /* 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);
    codec_id = OF_CODEC_LDPC_STAIRCASE_STABLE;
    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;
  }
  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 session now... */
  if ((ret = of_create_codec_instance(&ses, codec_id, OF_ENCODER, 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;
  }

  /* Allocate and initialize our source symbols...
   * In case of a file transmission, the opposite takes place: the file is read
   * and partitionned into a set of k source symbols. At the end, it's just
   * equivalent since there is a set of k source symbols that need to be sent
   * reliably thanks to an FEC encoding. */
  printf("\nFilling source symbols...\n");
  if ((enc_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;
  }
  /* In order to detect corruption, the first symbol is filled with 0x1111...,
   * the second with 0x2222..., etc. NB: the 0x0 value is avoided since it is a
   * neutral element in the target finite fields, i.e. it prevents the detection
   * of symbol corruption */
  for (esi = 0; esi < k; esi++) {
    if ((enc_symbols_tab[esi] = calloc(symb_sz_32, sizeof(UINT32))) == NULL) {
      OF_PRINT_ERROR(
          ("no memory (calloc failed for enc_symbols_tab[%d])\n", esi))
      ret = -1;
      goto end;
    }
    memset(enc_symbols_tab[esi], (char)(esi + 1), SYMBOL_SIZE);
    if (VERBOSITY > 1) {
      printf("src[%03d]= ", esi);
      dump_buffer_32(enc_symbols_tab[esi], 1);
    }
  }

  /* Now build the n-k repair symbols... */
  printf("\nBuilding repair symbols...\n");
  for (esi = k; esi < n; esi++) {
    if ((enc_symbols_tab[esi] = (char *)calloc(symb_sz_32, sizeof(UINT32))) ==
        NULL) {
      OF_PRINT_ERROR(
          ("no memory (calloc failed for enc_symbols_tab[%d])\n", esi))
      ret = -1;
      goto end;
    }
    if (of_build_repair_symbol(ses, enc_symbols_tab, esi) != OF_STATUS_OK) {
      OF_PRINT_ERROR(
          ("ERROR: of_build_repair_symbol() failed for esi=%u\n", esi))
      ret = -1;
      goto end;
    }
    if (VERBOSITY > 1) {
      printf("repair[%03d]= ", esi);
      dump_buffer_32(enc_symbols_tab[esi], 4);
    }
  }

  /* Randomize the packet order, it's important for LDPC-Staircase codes for
   * instance... */
  printf("\nRandomizing transmit order...\n");
  if ((rand_order = (UINT32 *)calloc(n, sizeof(UINT32))) == NULL) {
    OF_PRINT_ERROR(("no memory (calloc failed for rand_order)\n"))
    ret = -1;
    goto end;
  }
  randomize_array(&rand_order, n);

  /* Finally initialize the UDP socket and throw our packets... */
  if ((so = init_socket(&dst_host)) == INVALID_SOCKET) {
    OF_PRINT_ERROR(("Error initializing socket!\n"))
    ret = -1;
    goto end;
  }
  printf("First of all, send the FEC OTI for this object to %s/%d\n", DEST_IP,
         DEST_PORT);
  /* Initialize and send the FEC OTI to the client */
  /* convert back to host endianess */
  fec_oti.codec_id = htonl(codec_id);
  fec_oti.k = htonl(k);
  fec_oti.n = htonl(n);
  if ((ret = sendto(so, (void *)&fec_oti, sizeof(fec_oti), 0,
                    (SOCKADDR *)&dst_host, sizeof(dst_host))) !=
      sizeof(fec_oti)) {
    OF_PRINT_ERROR(("Error while sending the FEC OTI\n"))
    ret = -1;
    goto end;
  }

  lost_after_index = n * (1 - LOSS_RATE);
  if (lost_after_index < k) {
    OF_PRINT_ERROR(
        ("The loss rate %f is to high: only %u packets will be sent, whereas "
         "k=%u\n",
         LOSS_RATE, lost_after_index, k))
    ret = -1;
    goto end;
  }
  printf(
      "Sending %u source and repair packets to %s/%d. All packets sent at "
      "index %u and higher are considered as lost\n",
      n, DEST_IP, DEST_PORT, lost_after_index);
  /* Allocate a buffer where we'll copy each symbol plus its simplistif FPI (in
   * this example consisting only of the ESI). This needs to be fixed in real
   * applications, with the actual FPI required for this code. Also doing a
   * memcpy is rather suboptimal in terms of performance! */
  if ((pkt_with_fpi = (char *)malloc(4 + SYMBOL_SIZE)) == NULL) {
    OF_PRINT_ERROR(("no memory (malloc failed for pkt_with_fpi)\n"))
    ret = -1;
    goto end;
  }
  for (i = 0; i < n; i++) {
    if (i == lost_after_index) {
      /* the remaining packets are considered as lost, exit loop */
      break;
    }
    /* Add a pkt header wich only countains the ESI, i.e. a 32bits sequence
     * number, in network byte order in order to be portable regardless of the
     * local and remote byte endian representation (the receiver will do the
     * opposite with ntohl()...) */
    *(UINT32 *)pkt_with_fpi = htonl(rand_order[i]);
    memcpy(4 + pkt_with_fpi, enc_symbols_tab[rand_order[i]], SYMBOL_SIZE);
    printf("%05d => sending symbol %u (%s)\n", i + 1, rand_order[i],
           (rand_order[i] < k) ? "src" : "repair");
    if ((ret = sendto(so, pkt_with_fpi, SYMBOL_SIZE + 4, 0,
                      (SOCKADDR *)&dst_host, sizeof(dst_host))) ==
        SOCKET_ERROR) {
      OF_PRINT_ERROR(("sendto() failed!\n"))
      ret = -1;
      goto end;
    }
    /* Perform a short usleep() to slow down transmissions and avoid UDP socket
     * saturation at the receiver. Note that the true solution consists in
     * adding some rate control mechanism here, like a leaky or token bucket. */
    usleep(500);
  }
  printf("\nCompleted! %d packets sent successfully.\n", i);
  ret = 1;

end:
  /* Cleanup everything... */
  if (so != INVALID_SOCKET) {
    close(so);
  }
  if (ses) {
    of_release_codec_instance(ses);
  }
  if (params) {
    free(params);
  }
  if (rand_order) {
    free(rand_order);
  }
  if (enc_symbols_tab) {
    for (esi = 0; esi < n; esi++) {
      if (enc_symbols_tab[esi]) {
        free(enc_symbols_tab[esi]);
      }
    }
    free(enc_symbols_tab);
  }
  if (pkt_with_fpi) {
    free(pkt_with_fpi);
  }
  return ret;
}

/* Randomize an array of integers */
void randomize_array(UINT32 **array, UINT32 arrayLen) {
  UINT32 backup = 0;
  UINT32 randInd = 0;
  UINT32 seed; /* random seed for the srand() function */
  UINT32 i;

  struct timeval tv;
  if (gettimeofday(&tv, NULL) < 0) {
    OF_PRINT_ERROR(("gettimeofday() failed"))
    exit(-1);
  }
  seed = (int)tv.tv_usec;
  srand(seed);
  for (i = 0; i < arrayLen; i++) {
    (*array)[i] = i;
  }
  for (i = 0; i < arrayLen; i++) {
    backup = (*array)[i];
    randInd = rand() % arrayLen;
    (*array)[i] = (*array)[randInd];
    (*array)[randInd] = backup;
  }
}

/* Initialize our UDP socket */
static SOCKET init_socket(SOCKADDR_IN *dst_host) {
  SOCKET s;

  if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == INVALID_SOCKET) {
    printf("Error: call to socket() failed\n");
    return INVALID_SOCKET;
  }
  dst_host->sin_family = AF_INET;
  dst_host->sin_port = htons((short)DEST_PORT);
  dst_host->sin_addr.s_addr = inet_addr(DEST_IP);
  return s;
}

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");
}