sockets.c

lwip-1.4.0

/**
 * @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 <[e-mail]>
 *
 * Improved by Marc Boucher <[e-mail]> and David Haas <[e-mail]>
 *
 */

#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 "lwip/pbuf.h"
#if LWIP_CHECKSUM_ON_COPY
#include "lwip/inet_chksum.h"
#endif

#include <string.h>

#define NUM_SOCKETS MEMP_NUM_NETCONN

/** Contains all internal pointers and states used for a socket */
struct lwip_sock {
  /** sockets currently are built on netconns, each socket has one netconn */
  struct netconn *conn;
  /** data that was left from the previous read */
  void *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 ACKed (free send buffer), set by event_callback(),
      tested by select */
  u16_t sendevent;
  /** error happened for this socket, set by event_callback(), tested by select */
  u16_t errevent; 
  /** last error that occurred on this socket */
  int err;
  /** counter of how many threads are waiting for this socket using select */
  int select_waiting;
};

/** Description for a task waiting in select */
struct lwip_select_cb {
  /** Pointer to the next waiting task */
  struct lwip_select_cb *next;
  /** Pointer to the previous waiting task */
  struct lwip_select_cb *prev;
  /** 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_sock *sock;
#ifdef LWIP_DEBUG
  /** socket index for which to change options */
  int s;
#endif /* LWIP_DEBUG */
  /** 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_sock sockets[NUM_SOCKETS];
/** The global list of tasks waiting for select */
static struct lwip_select_cb *select_cb_list;
/** This counter is increased from lwip_select when the list is chagned
    and checked in event_callback to see if it has changed. */
static volatile int select_cb_ctr;

/** 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.            */
  EWOULDBLOCK,   /* ERR_TIMEOUT    -3      Timeout                  */
  EHOSTUNREACH,  /* ERR_RTE        -4      Routing problem.         */
  EINPROGRESS,   /* ERR_INPROGRESS -5      Operation in progress    */
  EINVAL,        /* ERR_VAL        -6      Illegal value.           */
  EWOULDBLOCK,   /* ERR_WOULDBLOCK -7      Operation would block.   */
  EADDRINUSE,    /* ERR_USE        -8      Address in use.          */
  EALREADY,      /* ERR_ISCONN     -9      Already connected.       */
  ECONNABORTED,  /* ERR_ABRT       -10     Connection aborted.      */
  ECONNRESET,    /* ERR_RST        -11     Connection reset.        */
  ENOTCONN,      /* ERR_CLSD       -12     Connection closed.       */
  ENOTCONN,      /* ERR_CONN       -13     Not connected.           */
  EIO,           /* ERR_ARG        -14     Illegal argument.        */
  -1,            /* ERR_IF         -15     Low-level netif error    */
};

#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 /* ERRNO */
#define set_errno(err)
#endif /* ERRNO */

#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)
{
}

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

/**
 * Same as get_socket but doesn't set errno
 *
 * @param s externally used socket index
 * @return struct lwip_sock for the socket or NULL if not found
 */
static struct lwip_sock *
tryget_socket(int s)
{
  if ((s < 0) || (s >= NUM_SOCKETS)) {
    return NULL;
  }
  if (!sockets[s].conn) {
    return NULL;
  }
  return &sockets[s];
}

/**
 * Allocate a new socket for a given netconn.
 *
 * @param newconn the netconn for which to allocate a socket
 * @param accepted 1 if socket has been created by accept(),
 *                 0 if socket has been created by socket()
 * @return the index of the new socket; -1 on error
 */
static int
alloc_socket(struct netconn *newconn, int accepted)
{
  int i;
  SYS_ARCH_DECL_PROTECT(lev);

  /* allocate a new socket identifier */
  for (i = 0; i < NUM_SOCKETS; ++i) {
    /* Protect socket array */
    SYS_ARCH_PROTECT(lev);
    if (!sockets[i].conn) {
      sockets[i].conn       = newconn;
      /* The socket is not yet known to anyone, so no need to protect
         after having marked it as used. */
      SYS_ARCH_UNPROTECT(lev);
      sockets[i].lastdata   = NULL;
      sockets[i].lastoffset = 0;
      sockets[i].rcvevent   = 0;
      /* TCP sendbuf is empty, but the socket is not yet writable until connected
       * (unless it has been created by accept()). */
      sockets[i].sendevent  = (newconn->type == NETCONN_TCP ? (accepted != 0) : 1);
      sockets[i].errevent   = 0;
      sockets[i].err        = 0;
      sockets[i].select_waiting = 0;
      return i;
    }
    SYS_ARCH_UNPROTECT(lev);
  }
  return -1;
}

/** Free a socket. The socket's netconn must have been
 * delete before!
 *
 * @param sock the socket to free
 * @param is_tcp != 0 for TCP sockets, used to free lastdata
 */
static void
free_socket(struct lwip_sock *sock, int is_tcp)
{
  void *lastdata;
  SYS_ARCH_DECL_PROTECT(lev);

  lastdata         = sock->lastdata;
  sock->lastdata   = NULL;
  sock->lastoffset = 0;
  sock->err        = 0;

  /* Protect socket array */
  SYS_ARCH_PROTECT(lev);
  sock->conn       = NULL;
  SYS_ARCH_UNPROTECT(lev);
  /* don't use 'sock' after this line, as another task might have allocated it */

  if (lastdata != NULL) {
    if (is_tcp) {
      pbuf_free((struct pbuf *)lastdata);
    } else {
      netbuf_delete((struct netbuf *)lastdata);
    }
  }
}

/* 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_sock *sock, *nsock;
  struct netconn *newconn;
  ip_addr_t naddr;
  u16_t port;
  int newsock;
  struct sockaddr_in sin;
  err_t err;
  SYS_ARCH_DECL_PROTECT(lev);

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

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

  /* wait for a new connection */
  err = netconn_accept(sock->conn, &newconn);
  if (err != ERR_OK) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): netconn_acept failed, err=%d\n", s, err));
    sock_set_errno(sock, err_to_errno(err));
    return -1;
  }
  LWIP_ASSERT("newconn != NULL", newconn != NULL);
  /* Prevent automatic window updates, we do this on our own! */
  netconn_set_noautorecved(newconn, 1);

  /* get the IP address and port of the remote host */
  err = netconn_peer(newconn, &naddr, &port);
  if (err != ERR_OK) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): netconn_peer failed, err=%d\n", s, err));
    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);
    inet_addr_from_ipaddr(&sin.sin_addr, &naddr);

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

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

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

  /* 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!
   */
  SYS_ARCH_PROTECT(lev);
  nsock->rcvevent += (s16_t)(-1 - newconn->socket);
  newconn->socket = newsock;
  SYS_ARCH_UNPROTECT(lev);

  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_sock *sock;
  ip_addr_t local_addr;
  u16_t local_port;
  err_t err;
  const struct sockaddr_in *name_in;

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

  /* check size, familiy and alignment of 'name' */
  LWIP_ERROR("lwip_bind: invalid address", ((namelen == sizeof(struct sockaddr_in)) &&
             ((name->sa_family) == AF_INET) && ((((mem_ptr_t)name) % 4) == 0)),
             sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);
  name_in = (const struct sockaddr_in *)(void*)name;

  inet_addr_to_ipaddr(&local_addr, &name_in->sin_addr);
  local_port = name_in->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)
{