/*

 * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson

 * Copyright (c) 2002-2006 Niels Provos <provos@citi.umich.edu>

 * 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.

 */

#include "event2/event-config.h"

#include "evconfig-private.h"

#include <sys/types.h>

#ifdef EVENT__HAVE_SYS_TIME_H

#include <sys/time.h>

#endif

#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#ifdef EVENT__HAVE_STDARG_H

#include <stdarg.h>

#endif

#ifdef EVENT__HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef _WIN32

#include <winsock2.h>

#include <ws2tcpip.h>

#endif

#ifdef EVENT__HAVE_SYS_SOCKET_H

#include <sys/socket.h>

#endif

#ifdef EVENT__HAVE_NETINET_IN_H

#include <netinet/in.h>

#endif

#ifdef EVENT__HAVE_NETINET_IN6_H

#include <netinet/in6.h>

#endif

#include "event2/util.h"

#include "event2/bufferevent.h"

#include "event2/buffer.h"

#include "event2/bufferevent_struct.h"

#include "event2/bufferevent_compat.h"

#include "event2/event.h"

#include "log-internal.h"

#include "mm-internal.h"

#include "bufferevent-internal.h"

#include "util-internal.h"

#ifdef _WIN32

#include "iocp-internal.h"

#endif

/* prototypes */

static int be_socket_enable(struct bufferevent *, short);

static int be_socket_disable(struct bufferevent *, short);

static void be_socket_destruct(struct bufferevent *);

static int be_socket_flush(struct bufferevent *, short, enum bufferevent_flush_mode);

static int be_socket_ctrl(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *);

static void be_socket_setfd(struct bufferevent *, evutil_socket_t);

const struct bufferevent_ops bufferevent_ops_socket = {

  "socket",

  evutil_offsetof(struct bufferevent_private, bev),

  be_socket_enable,

  be_socket_disable,

  NULL, /* unlink */

  be_socket_destruct,

  bufferevent_generic_adj_existing_timeouts_,

  be_socket_flush,

  be_socket_ctrl,

};

const struct sockaddr*

bufferevent_socket_get_conn_address_(struct bufferevent *bev)

{

  struct bufferevent_private *bev_p = BEV_UPCAST(bev);

  return (struct sockaddr *)&bev_p->conn_address;

}

void

bufferevent_socket_set_conn_address_fd_(struct bufferevent *bev,

  evutil_socket_t fd)

{

  struct bufferevent_private *bev_p = BEV_UPCAST(bev);

  socklen_t len = sizeof(bev_p->conn_address);

  struct sockaddr *addr = (struct sockaddr *)&bev_p->conn_address;

  if (addr->sa_family != AF_UNSPEC)

    getpeername(fd, addr, &len);

}

void

bufferevent_socket_set_conn_address_(struct bufferevent *bev,

  struct sockaddr *addr, size_t addrlen)

{

  struct bufferevent_private *bev_p = BEV_UPCAST(bev);

  EVUTIL_ASSERT(addrlen <= sizeof(bev_p->conn_address));

  memcpy(&bev_p->conn_address, addr, addrlen);

}

static void

bufferevent_socket_outbuf_cb(struct evbuffer *buf,

    const struct evbuffer_cb_info *cbinfo,

    void *arg)

{

  struct bufferevent *bufev = arg;

  struct bufferevent_private *bufev_p = BEV_UPCAST(bufev);

  if (cbinfo->n_added &&

      (bufev->enabled & EV_WRITE) &&

      !event_pending(&bufev->ev_write, EV_WRITE, NULL) &&

      !bufev_p->write_suspended) {

    /* Somebody added data to the buffer, and we would like to

     * write, and we were not writing.  So, start writing. */

    if (bufferevent_add_event_(&bufev->ev_write, &bufev->timeout_write) == -1) {

        /* Should we log this? */

    }

  }

}

static void

bufferevent_readcb(evutil_socket_t fd, short event, void *arg)

{

  struct bufferevent *bufev = arg;

  struct bufferevent_private *bufev_p = BEV_UPCAST(bufev);

  struct evbuffer *input;

  int res = 0;

  short what = BEV_EVENT_READING;

  ev_ssize_t howmuch = -1, readmax=-1;

  bufferevent_incref_and_lock_(bufev);

  if (event == EV_TIMEOUT) {

    /* Note that we only check for event==EV_TIMEOUT. If

     * event==EV_TIMEOUT|EV_READ, we can safely ignore the

     * timeout, since a read has occurred */

    what |= BEV_EVENT_TIMEOUT;

    goto error;

  }

  input = bufev->input;

  /*

   * If we have a high watermark configured then we don't want to

   * read more data than would make us reach the watermark.

   */

  if (bufev->wm_read.high != 0) {

    howmuch = bufev->wm_read.high - evbuffer_get_length(input);

    /* we somehow lowered the watermark, stop reading */

    if (howmuch <= 0) {

      bufferevent_wm_suspend_read(bufev);

      goto done;

    }

  }

  readmax = bufferevent_get_read_max_(bufev_p);

  if (howmuch < 0 || howmuch > readmax) /* The use of -1 for "unlimited"

                 * uglifies this code. XXXX */

    howmuch = readmax;

  if (bufev_p->read_suspended)

    goto done;

  evbuffer_unfreeze(input, 0);

  res = evbuffer_read(input, fd, (int)howmuch); /* XXXX evbuffer_read would do better to take and return ev_ssize_t */

  evbuffer_freeze(input, 0);

  if (res == -1) {

    int err = evutil_socket_geterror(fd);

    if (EVUTIL_ERR_RW_RETRIABLE(err))

      goto reschedule;

    if (EVUTIL_ERR_CONNECT_REFUSED(err)) {

      bufev_p->connection_refused = 1;

      goto done;

    }

    /* error case */

    what |= BEV_EVENT_ERROR;

  } else if (res == 0) {

    /* eof case */

    what |= BEV_EVENT_EOF;

  }

  if (res <= 0)

    goto error;

  bufferevent_decrement_read_buckets_(bufev_p, res);

  /* Invoke the user callback - must always be called last */

  bufferevent_trigger_nolock_(bufev, EV_READ, 0);

  goto done;

 reschedule:

  goto done;

 error:

  bufferevent_disable(bufev, EV_READ);

  bufferevent_run_eventcb_(bufev, what, 0);

 done:

  bufferevent_decref_and_unlock_(bufev);

}

static void

bufferevent_writecb(evutil_socket_t fd, short event, void *arg)

{

  struct bufferevent *bufev = arg;

  struct bufferevent_private *bufev_p = BEV_UPCAST(bufev);

  int res = 0;

  short what = BEV_EVENT_WRITING;

  int connected = 0;

  ev_ssize_t atmost = -1;

  bufferevent_incref_and_lock_(bufev);

  if (event == EV_TIMEOUT) {

    /* Note that we only check for event==EV_TIMEOUT. If

     * event==EV_TIMEOUT|EV_WRITE, we can safely ignore the

     * timeout, since a read has occurred */

    what |= BEV_EVENT_TIMEOUT;

    goto error;

  }

  if (bufev_p->connecting) {

    int c = evutil_socket_finished_connecting_(fd);

    /* we need to fake the error if the connection was refused

     * immediately - usually connection to localhost on BSD */

    if (bufev_p->connection_refused) {

      bufev_p->connection_refused = 0;

      c = -1;

    }

    if (c == 0)

      goto done;

    bufev_p->connecting = 0;

    if (c < 0) {

      event_del(&bufev->ev_write);

      event_del(&bufev->ev_read);

      bufferevent_run_eventcb_(bufev, BEV_EVENT_ERROR, 0);

      goto done;

    } else {

      connected = 1;

      bufferevent_socket_set_conn_address_fd_(bufev, fd);

#ifdef _WIN32

      if (BEV_IS_ASYNC(bufev)) {

        event_del(&bufev->ev_write);

        bufferevent_async_set_connected_(bufev);

        bufferevent_run_eventcb_(bufev,

            BEV_EVENT_CONNECTED, 0);

        goto done;

      }

#endif

      bufferevent_run_eventcb_(bufev,

          BEV_EVENT_CONNECTED, 0);

      if (!(bufev->enabled & EV_WRITE) ||

          bufev_p->write_suspended) {

        event_del(&bufev->ev_write);

        goto done;

      }

    }

  }

  atmost = bufferevent_get_write_max_(bufev_p);

  if (bufev_p->write_suspended)

    goto done;

  if (evbuffer_get_length(bufev->output)) {

    evbuffer_unfreeze(bufev->output, 1);

    res = evbuffer_write_atmost(bufev->output, fd, atmost);

    evbuffer_freeze(bufev->output, 1);

    if (res == -1) {

      int err = evutil_socket_geterror(fd);

      if (EVUTIL_ERR_RW_RETRIABLE(err))

        goto reschedule;

      what |= BEV_EVENT_ERROR;

    } else if (res == 0) {

      /* eof case

         XXXX Actually, a 0 on write doesn't indicate

         an EOF. An ECONNRESET might be more typical.

       */

      what |= BEV_EVENT_EOF;

    }

    if (res <= 0)

      goto error;

    bufferevent_decrement_write_buckets_(bufev_p, res);

  }

  if (evbuffer_get_length(bufev->output) == 0) {

    event_del(&bufev->ev_write);

  }

  /*

   * Invoke the user callback if our buffer is drained or below the

   * low watermark.

   */

  if (res || !connected) {

    bufferevent_trigger_nolock_(bufev, EV_WRITE, 0);

  }

  goto done;

 reschedule:

  if (evbuffer_get_length(bufev->output) == 0) {

    event_del(&bufev->ev_write);

  }

  goto done;

 error:

  bufferevent_disable(bufev, EV_WRITE);

  bufferevent_run_eventcb_(bufev, what, 0);

 done:

  bufferevent_decref_and_unlock_(bufev);

}

struct bufferevent *

bufferevent_socket_new(struct event_base *base, evutil_socket_t fd,

    int options)

{

  struct bufferevent_private *bufev_p;

  struct bufferevent *bufev;

#ifdef _WIN32

  if (base && event_base_get_iocp_(base))

    return bufferevent_async_new_(base, fd, options);

#endif

  if ((bufev_p = mm_calloc(1, sizeof(struct bufferevent_private)))== NULL)

    return NULL;

  if (bufferevent_init_common_(bufev_p, base, &bufferevent_ops_socket,

            options) < 0) {

    mm_free(bufev_p);

    return NULL;

  }

  bufev = &bufev_p->bev;

  evbuffer_set_flags(bufev->output, EVBUFFER_FLAG_DRAINS_TO_FD);

  event_assign(&bufev->ev_read, bufev->ev_base, fd,

      EV_READ|EV_PERSIST|EV_FINALIZE, bufferevent_readcb, bufev);

  event_assign(&bufev->ev_write, bufev->ev_base, fd,

      EV_WRITE|EV_PERSIST|EV_FINALIZE, bufferevent_writecb, bufev);

  evbuffer_add_cb(bufev->output, bufferevent_socket_outbuf_cb, bufev);

  evbuffer_freeze(bufev->input, 0);

  evbuffer_freeze(bufev->output, 1);

  return bufev;

}

int

bufferevent_socket_connect(struct bufferevent *bev,

    const struct sockaddr *sa, int socklen)

{

  struct bufferevent_private *bufev_p = BEV_UPCAST(bev);

  evutil_socket_t fd;

  int r = 0;

  int result=-1;

  int ownfd = 0;

  bufferevent_incref_and_lock_(bev);

  fd = bufferevent_getfd(bev);

  if (fd < 0) {

    if (!sa)

      goto done;

    fd = evutil_socket_(sa->sa_family,

        SOCK_STREAM|EVUTIL_SOCK_NONBLOCK, 0);

    if (fd < 0)

      goto freesock;

    ownfd = 1;

  }

  if (sa) {

#ifdef _WIN32

    if (bufferevent_async_can_connect_(bev)) {

      bufferevent_setfd(bev, fd);

      r = bufferevent_async_connect_(bev, fd, sa, socklen);

      if (r < 0)

        goto freesock;

      bufev_p->connecting = 1;

      result = 0;

      goto done;

    } else

#endif

    r = evutil_socket_connect_(&fd, sa, socklen);

    if (r < 0)

      goto freesock;

  }

#ifdef _WIN32

  /* ConnectEx() isn't always around, even when IOCP is enabled.

   * Here, we borrow the socket object's write handler to fall back

   * on a non-blocking connect() when ConnectEx() is unavailable. */

  if (BEV_IS_ASYNC(bev)) {

    event_assign(&bev->ev_write, bev->ev_base, fd,

        EV_WRITE|EV_PERSIST|EV_FINALIZE, bufferevent_writecb, bev);

  }

#endif

  bufferevent_setfd(bev, fd);

  if (r == 0) {

    if (! be_socket_enable(bev, EV_WRITE)) {

      bufev_p->connecting = 1;

      result = 0;

      goto done;

    }

  } else if (r == 1) {

    /* The connect succeeded already. How very BSD of it. */

    result = 0;

    bufev_p->connecting = 1;

    bufferevent_trigger_nolock_(bev, EV_WRITE, BEV_OPT_DEFER_CALLBACKS);

  } else {

    /* The connect failed already.  How very BSD of it. */

    result = 0;

    bufferevent_run_eventcb_(bev, BEV_EVENT_ERROR, BEV_OPT_DEFER_CALLBACKS);

    bufferevent_disable(bev, EV_WRITE|EV_READ);

  }

  goto done;

freesock:

  if (ownfd)

    evutil_closesocket(fd);

done:

  bufferevent_decref_and_unlock_(bev);

  return result;

}

static void

bufferevent_connect_getaddrinfo_cb(int result, struct evutil_addrinfo *ai,

    void *arg)

{

  struct bufferevent *bev = arg;

  struct bufferevent_private *bev_p = BEV_UPCAST(bev);

  int r;

  BEV_LOCK(bev);

  bufferevent_unsuspend_write_(bev, BEV_SUSPEND_LOOKUP);

  bufferevent_unsuspend_read_(bev, BEV_SUSPEND_LOOKUP);

  bev_p->dns_request = NULL;

  if (result == EVUTIL_EAI_CANCEL) {

    bev_p->dns_error = result;

    bufferevent_decref_and_unlock_(bev);

    return;

  }

  if (result != 0) {

    bev_p->dns_error = result;

    bufferevent_run_eventcb_(bev, BEV_EVENT_ERROR, 0);

    bufferevent_decref_and_unlock_(bev);

    if (ai)

      evutil_freeaddrinfo(ai);

    return;

  }

  /* XXX use the other addrinfos? */

  bufferevent_socket_set_conn_address_(bev, ai->ai_addr, (int)ai->ai_addrlen);

  r = bufferevent_socket_connect(bev, ai->ai_addr, (int)ai->ai_addrlen);

  if (r < 0)

    bufferevent_run_eventcb_(bev, BEV_EVENT_ERROR, 0);

  bufferevent_decref_and_unlock_(bev);

  evutil_freeaddrinfo(ai);

}

int

bufferevent_socket_connect_hostname(struct bufferevent *bev,

    struct evdns_base *evdns_base, int family, const char *hostname, int port)

{

  char portbuf[10];

  struct evutil_addrinfo hint;

  struct bufferevent_private *bev_p = BEV_UPCAST(bev);

  if (family != AF_INET && family != AF_INET6 && family != AF_UNSPEC)

    return -1;

  if (port < 1 || port > 65535)

    return -1;

  memset(&hint, 0, sizeof(hint));

  hint.ai_family = family;

  hint.ai_protocol = IPPROTO_TCP;

  hint.ai_socktype = SOCK_STREAM;

  evutil_snprintf(portbuf, sizeof(portbuf), "%d", port);

  BEV_LOCK(bev);

  bev_p->dns_error = 0;

  bufferevent_suspend_write_(bev, BEV_SUSPEND_LOOKUP);

  bufferevent_suspend_read_(bev, BEV_SUSPEND_LOOKUP);

  bufferevent_incref_(bev);

  bev_p->dns_request = evutil_getaddrinfo_async_(evdns_base, hostname,

      portbuf, &hint, bufferevent_connect_getaddrinfo_cb, bev);

  BEV_UNLOCK(bev);

  return 0;

}

int

bufferevent_socket_get_dns_error(struct bufferevent *bev)

{

  int rv;

  struct bufferevent_private *bev_p = BEV_UPCAST(bev);

  BEV_LOCK(bev);

  rv = bev_p->dns_error;

  BEV_UNLOCK(bev);

  return rv;

}

/*

 * Create a new buffered event object.

 *

 * The read callback is invoked whenever we read new data.

 * The write callback is invoked whenever the output buffer is drained.

 * The error callback is invoked on a write/read error or on EOF.

 *

 * Both read and write callbacks maybe NULL.  The error callback is not

 * allowed to be NULL and have to be provided always.

 */

struct bufferevent *

bufferevent_new(evutil_socket_t fd,

    bufferevent_data_cb readcb, bufferevent_data_cb writecb,

    bufferevent_event_cb eventcb, void *cbarg)

{

  struct bufferevent *bufev;

  if (!(bufev = bufferevent_socket_new(NULL, fd, 0)))

    return NULL;

  bufferevent_setcb(bufev, readcb, writecb, eventcb, cbarg);

  return bufev;

}

static int

be_socket_enable(struct bufferevent *bufev, short event)

{

  if (event & EV_READ &&

      bufferevent_add_event_(&bufev->ev_read, &bufev->timeout_read) == -1)

      return -1;

  if (event & EV_WRITE &&

      bufferevent_add_event_(&bufev->ev_write, &bufev->timeout_write) == -1)

      return -1;

  return 0;

}

static int

be_socket_disable(struct bufferevent *bufev, short event)

{

  struct bufferevent_private *bufev_p = BEV_UPCAST(bufev);

  if (event & EV_READ) {

    if (event_del(&bufev->ev_read) == -1)

      return -1;

  }

  /* Don't actually disable the write if we are trying to connect. */

  if ((event & EV_WRITE) && ! bufev_p->connecting) {

    if (event_del(&bufev->ev_write) == -1)

      return -1;

  }

  return 0;

}

static void

be_socket_destruct(struct bufferevent *bufev)

{

  struct bufferevent_private *bufev_p = BEV_UPCAST(bufev);

  evutil_socket_t fd;

  EVUTIL_ASSERT(BEV_IS_SOCKET(bufev));

  fd = event_get_fd(&bufev->ev_read);

  if ((bufev_p->options & BEV_OPT_CLOSE_ON_FREE) && fd >= 0)

    EVUTIL_CLOSESOCKET(fd);

  evutil_getaddrinfo_cancel_async_(bufev_p->dns_request);

}

static int

be_socket_flush(struct bufferevent *bev, short iotype,

    enum bufferevent_flush_mode mode)

{

  return 0;

}

static void

be_socket_setfd(struct bufferevent *bufev, evutil_socket_t fd)

{

  struct bufferevent_private *bufev_p = BEV_UPCAST(bufev);

  BEV_LOCK(bufev);

  EVUTIL_ASSERT(BEV_IS_SOCKET(bufev));

  event_del(&bufev->ev_read);

  event_del(&bufev->ev_write);

  evbuffer_unfreeze(bufev->input, 0);

  evbuffer_unfreeze(bufev->output, 1);

  event_assign(&bufev->ev_read, bufev->ev_base, fd,

      EV_READ|EV_PERSIST|EV_FINALIZE, bufferevent_readcb, bufev);

  event_assign(&bufev->ev_write, bufev->ev_base, fd,

      EV_WRITE|EV_PERSIST|EV_FINALIZE, bufferevent_writecb, bufev);

  if (fd >= 0)

    bufferevent_enable(bufev, bufev->enabled);

  evutil_getaddrinfo_cancel_async_(bufev_p->dns_request);

  BEV_UNLOCK(bufev);

}

/* XXXX Should non-socket bufferevents support this? */

int

bufferevent_priority_set(struct bufferevent *bufev, int priority)

{

  int r = -1;

  struct bufferevent_private *bufev_p = BEV_UPCAST(bufev);

  BEV_LOCK(bufev);

  if (BEV_IS_ASYNC(bufev) || BEV_IS_FILTER(bufev) || BEV_IS_PAIR(bufev))

    goto done;

  if (event_priority_set(&bufev->ev_read, priority) == -1)

    goto done;

  if (event_priority_set(&bufev->ev_write, priority) == -1)

    goto done;

  event_deferred_cb_set_priority_(&bufev_p->deferred, priority);

  r = 0;

done:

  BEV_UNLOCK(bufev);

  return r;

}

/* XXXX Should non-socket bufferevents support this? */

int

bufferevent_base_set(struct event_base *base, struct bufferevent *bufev)

{

  int res = -1;

  BEV_LOCK(bufev);

  if (!BEV_IS_SOCKET(bufev))

    goto done;

  bufev->ev_base = base;

  res = event_base_set(base, &bufev->ev_read);

  if (res == -1)

    goto done;

  res = event_base_set(base, &bufev->ev_write);

done:

  BEV_UNLOCK(bufev);

  return res;

}

static int

be_socket_ctrl(struct bufferevent *bev, enum bufferevent_ctrl_op op,

    union bufferevent_ctrl_data *data)

{

  switch (op) {

  case BEV_CTRL_SET_FD:

    be_socket_setfd(bev, data->fd);

    return 0;

  case BEV_CTRL_GET_FD:

    data->fd = event_get_fd(&bev->ev_read);

    return 0;

  case BEV_CTRL_GET_UNDERLYING:

  case BEV_CTRL_CANCEL_ALL:

  default:

    return -1;

  }

}