/**
 * @file
 * Sockets BSD-Like API module
 *
 */

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 * Improved by Marc Boucher <marc@mbsi.ca> and David Haas <dhaas@alum.rpi.edu>
 *
 */

#include "lwip/opt.h"

#if LWIP_SOCKET /* don't build if not configured for use in lwipopts.h */

#include "lwip/sockets.h"
#include "lwip/api.h"
#include "lwip/sys.h"
#include "lwip/igmp.h"
#include "lwip/inet.h"
#include "lwip/tcp.h"
#include "lwip/raw.h"
#include "lwip/udp.h"
#include "lwip/tcpip.h"

#include <string.h>

#define NUM_SOCKETS MEMP_NUM_NETCONN

/** Contains all internal pointers and states used for a socket */
struct lwip_socket {
  /** sockets currently are built on netconns, each socket has one netconn */
  struct netconn *conn;
  /** data that was left from the previous read */
  struct netbuf *lastdata;
  /** offset in the data that was left from the previous read */
  u16_t lastoffset;
  /** number of times data was received, set by event_callback(),
      tested by the receive and select functions */
  s16_t rcvevent;
  /** number of times data was received, set by event_callback(),
      tested by select */
  u16_t sendevent;
  /** socket flags (currently, only used for O_NONBLOCK) */
  u16_t flags;
  /** last error that occurred on this socket */
  int err;
};

/** Description for a task waiting in select */
struct lwip_select_cb {
  /** Pointer to the next waiting task */
  struct lwip_select_cb *next;
  /** readset passed to select */
  fd_set *readset;
  /** writeset passed to select */
  fd_set *writeset;
  /** unimplemented: exceptset passed to select */
  fd_set *exceptset;
  /** don't signal the same semaphore twice: set to 1 when signalled */
  int sem_signalled;
  /** semaphore to wake up a task waiting for select */
  sys_sem_t sem;
};

/** This struct is used to pass data to the set/getsockopt_internal
 * functions running in tcpip_thread context (only a void* is allowed) */
struct lwip_setgetsockopt_data {
  /** socket struct for which to change options */
  struct lwip_socket *sock;
  /** socket index for which to change options */
  int s;
  /** level of the option to process */
  int level;
  /** name of the option to process */
  int optname;
  /** set: value to set the option to
    * get: value of the option is stored here */
  void *optval;
  /** size of *optval */
  socklen_t *optlen;
  /** if an error occures, it is temporarily stored here */
  err_t err;
};

/** The global array of available sockets */
static struct lwip_socket sockets[NUM_SOCKETS];
/** The global list of tasks waiting for select */
static struct lwip_select_cb *select_cb_list;

/** Semaphore protecting the sockets array */
static sys_sem_t socksem;
/** Semaphore protecting select_cb_list */
static sys_sem_t selectsem;

/** Table to quickly map an lwIP error (err_t) to a socket error
  * by using -err as an index */
static const int err_to_errno_table[] = {
  0,             /* ERR_OK          0      No error, everything OK. */
  ENOMEM,        /* ERR_MEM        -1      Out of memory error.     */
  ENOBUFS,       /* ERR_BUF        -2      Buffer error.            */
  ETIMEDOUT,     /* ERR_TIMEOUT    -3      Timeout                  */
  EHOSTUNREACH,  /* ERR_RTE        -4      Routing problem.         */
  ECONNABORTED,  /* ERR_ABRT       -5      Connection aborted.      */
  ECONNRESET,    /* ERR_RST        -6      Connection reset.        */
  ESHUTDOWN,     /* ERR_CLSD       -7      Connection closed.       */
  ENOTCONN,      /* ERR_CONN       -8      Not connected.           */
  EINVAL,        /* ERR_VAL        -9      Illegal value.           */
  EIO,           /* ERR_ARG        -10     Illegal argument.        */
  EADDRINUSE,    /* ERR_USE        -11     Address in use.          */
  -1,            /* ERR_IF         -12     Low-level netif error    */
  -1,            /* ERR_ISCONN     -13     Already connected.       */
  EINPROGRESS    /* ERR_INPROGRESS -14     Operation in progress    */
};

#define ERR_TO_ERRNO_TABLE_SIZE \
  (sizeof(err_to_errno_table)/sizeof(err_to_errno_table[0]))

#define err_to_errno(err) \
  ((unsigned)(-(err)) < ERR_TO_ERRNO_TABLE_SIZE ? \
    err_to_errno_table[-(err)] : EIO)

#ifdef ERRNO
#ifndef set_errno
#define set_errno(err) errno = (err)
#endif
#else
#define set_errno(err)
#endif

#define sock_set_errno(sk, e) do { \
  sk->err = (e); \
  set_errno(sk->err); \
} while (0)

/* Forward delcaration of some functions */
static void event_callback(struct netconn *conn, enum netconn_evt evt, u16_t len);
static void lwip_getsockopt_internal(void *arg);
static void lwip_setsockopt_internal(void *arg);

/**
 * Initialize this module. This function has to be called before any other
 * functions in this module!
 */
void
lwip_socket_init(void)
{
  socksem   = sys_sem_new(1);
  selectsem = sys_sem_new(1);
}

/**
 * Map a externally used socket index to the internal socket representation.
 *
 * @param s externally used socket index
 * @return struct lwip_socket for the socket or NULL if not found
 */
static struct lwip_socket *
get_socket(int s)
{
  struct lwip_socket *sock;

  if ((s < 0) || (s >= NUM_SOCKETS)) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("get_socket(%d): invalid\n", s));
    set_errno(EBADF);
    return NULL;
  }

  sock = &sockets[s];

  if (!sock->conn) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("get_socket(%d): not active\n", s));
    set_errno(EBADF);
    return NULL;
  }

  return sock;
}

/**
 * Allocate a new socket for a given netconn.
 *
 * @param newconn the netconn for which to allocate a socket
 * @return the index of the new socket; -1 on error
 */
static int
alloc_socket(struct netconn *newconn)
{
  int i;

  /* Protect socket array */
  sys_sem_wait(socksem);

  /* allocate a new socket identifier */
  for (i = 0; i < NUM_SOCKETS; ++i) {
    if (!sockets[i].conn) {
      sockets[i].conn       = newconn;
      sockets[i].lastdata   = NULL;
      sockets[i].lastoffset = 0;
      sockets[i].rcvevent   = 0;
      sockets[i].sendevent  = 1; /* TCP send buf is empty */
      sockets[i].flags      = 0;
      sockets[i].err        = 0;
      sys_sem_signal(socksem);
      return i;
    }
  }
  sys_sem_signal(socksem);
  return -1;
}

/* Below this, the well-known socket functions are implemented.
 * Use google.com or opengroup.org to get a good description :-)
 *
 * Exceptions are documented!
 */

int
lwip_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
{
  struct lwip_socket *sock, *nsock;
  struct netconn *newconn;
  struct ip_addr naddr;
  u16_t port;
  int newsock;
  struct sockaddr_in sin;
  err_t err;

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d)...\n", s));
  sock = get_socket(s);
  if (!sock)
    return -1;

  if ((sock->flags & O_NONBLOCK) && (sock->rcvevent <= 0)) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): returning EWOULDBLOCK\n", s));
    sock_set_errno(sock, EWOULDBLOCK);
    return -1;
  }

  newconn = netconn_accept(sock->conn);
  if (!newconn) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d) failed, err=%d\n", s, sock->conn->err));
    sock_set_errno(sock, err_to_errno(sock->conn->err));
    return -1;
  }

  /* get the IP address and port of the remote host */
  err = netconn_peer(newconn, &naddr, &port);
  if (err != ERR_OK) {
    netconn_delete(newconn);
    sock_set_errno(sock, err_to_errno(err));
    return -1;
  }

  /* Note that POSIX only requires us to check addr is non-NULL. addrlen must
   * not be NULL if addr is valid.
   */
  if (NULL != addr) {
    LWIP_ASSERT("addr valid but addrlen NULL", addrlen != NULL);
    memset(&sin, 0, sizeof(sin));
    sin.sin_len = sizeof(sin);
    sin.sin_family = AF_INET;
    sin.sin_port = htons(port);
    sin.sin_addr.s_addr = naddr.addr;

    if (*addrlen > sizeof(sin))
      *addrlen = sizeof(sin);

    MEMCPY(addr, &sin, *addrlen);
  }

  newsock = alloc_socket(newconn);
  if (newsock == -1) {
    netconn_delete(newconn);
    sock_set_errno(sock, ENFILE);
    return -1;
  }
  LWIP_ASSERT("invalid socket index", (newsock >= 0) && (newsock < NUM_SOCKETS));
  newconn->callback = event_callback;
  nsock = &sockets[newsock];
  LWIP_ASSERT("invalid socket pointer", nsock != NULL);

  sys_sem_wait(socksem);
  /* See event_callback: If data comes in right away after an accept, even
   * though the server task might not have created a new socket yet.
   * In that case, newconn->socket is counted down (newconn->socket--),
   * so nsock->rcvevent is >= 1 here!
   */
  nsock->rcvevent += -1 - newconn->socket;
  newconn->socket = newsock;
  sys_sem_signal(socksem);

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d) returning new sock=%d addr=", s, newsock));
  ip_addr_debug_print(SOCKETS_DEBUG, &naddr);
  LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F"\n", port));

  sock_set_errno(sock, 0);
  return newsock;
}

int
lwip_bind(int s, const struct sockaddr *name, socklen_t namelen)
{
  struct lwip_socket *sock;
  struct ip_addr local_addr;
  u16_t local_port;
  err_t err;

  sock = get_socket(s);
  if (!sock)
    return -1;

  LWIP_ERROR("lwip_bind: invalid address", ((namelen == sizeof(struct sockaddr_in)) &&
             ((((const struct sockaddr_in *)name)->sin_family) == AF_INET)),
             sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);

  local_addr.addr = ((const struct sockaddr_in *)name)->sin_addr.s_addr;
  local_port = ((const struct sockaddr_in *)name)->sin_port;

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_bind(%d, addr=", s));
  ip_addr_debug_print(SOCKETS_DEBUG, &local_addr);
  LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F")\n", ntohs(local_port)));

  err = netconn_bind(sock->conn, &local_addr, ntohs(local_port));

  if (err != ERR_OK) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_bind(%d) failed, err=%d\n", s, err));
    sock_set_errno(sock, err_to_errno(err));
    return -1;
  }

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_bind(%d) succeeded\n", s));
  sock_set_errno(sock, 0);
  return 0;
}

int
lwip_close(int s)
{
  struct lwip_socket *sock;

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_close(%d)\n", s));

  sock = get_socket(s);
  if (!sock) {
    return -1;
  }

  netconn_delete(sock->conn);

  sys_sem_wait(socksem);
  if (sock->lastdata) {
    netbuf_delete(sock->lastdata);
  }
  sock->lastdata   = NULL;
  sock->lastoffset = 0;
  sock->conn       = NULL;
  sock_set_errno(sock, 0);
  sys_sem_signal(socksem);
  return 0;
}

int
lwip_connect(int s, const struct sockaddr *name, socklen_t namelen)
{
  struct lwip_socket *sock;
  err_t err;

  sock = get_socket(s);
  if (!sock)
    return -1;

  LWIP_ERROR("lwip_connect: invalid address", ((namelen == sizeof(struct sockaddr_in)) &&
             ((((const struct sockaddr_in *)name)->sin_family) == AF_INET)),
             sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);

  if (((const struct sockaddr_in *)name)->sin_family == AF_UNSPEC) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d, AF_UNSPEC)\n", s));
    err = netconn_disconnect(sock->conn);
  } else {
    struct ip_addr remote_addr;
    u16_t remote_port;

    remote_addr.addr = ((const struct sockaddr_in *)name)->sin_addr.s_addr;
    remote_port = ((const struct sockaddr_in *)name)->sin_port;

    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d, addr=", s));
    ip_addr_debug_print(SOCKETS_DEBUG, &remote_addr);
    LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F")\n", ntohs(remote_port)));

    err = netconn_connect(sock->conn, &remote_addr, ntohs(remote_port));
  }

  if (err != ERR_OK) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d) failed, err=%d\n", s, err));
    sock_set_errno(sock, err_to_errno(err));
    return -1;
  }

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d) succeeded\n", s));
  sock_set_errno(sock, 0);
  return 0;
}

/**
 * Set a socket into listen mode.
 * The socket may not have been used for another connection previously.
 *
 * @param s the socket to set to listening mode
 * @param backlog (ATTENTION: need TCP_LISTEN_BACKLOG=1)
 * @return 0 on success, non-zero on failure
 */
int
lwip_listen(int s, int backlog)
{
  struct lwip_socket *sock;
  err_t err;

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_listen(%d, backlog=%d)\n", s, backlog));

  sock = get_socket(s);
  if (!sock)
    return -1;

  /* limit the "backlog" parameter to fit in an u8_t */
  if (backlog < 0) {
    backlog = 0;
  }
  if (backlog > 0xff) {
    backlog = 0xff;
  }

  err = netconn_listen_with_backlog(sock->conn, backlog);

  if (err != ERR_OK) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_listen(%d) failed, err=%d\n", s, err));
    sock_set_errno(sock, err_to_errno(err));
    return -1;
  }

  sock_set_errno(sock, 0);
  return 0;
}

int
lwip_recvfrom(int s, void *mem, size_t len, int flags,
        struct sockaddr *from, socklen_t *fromlen)
{
  struct lwip_socket *sock;
  struct netbuf      *buf;
  u16_t               buflen, copylen, off = 0;
  struct ip_addr     *addr;
  u16_t               port;
  u8_t                done = 0;

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d, %p, %"SZT_F", 0x%x, ..)\n", s, mem, len, flags));
  sock = get_socket(s);
  if (!sock)
    return -1;

  do {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: top while sock->lastdata=%p\n", (void*)sock->lastdata));
    /* Check if there is data left from the last recv operation. */
    if (sock->lastdata) {