/*

 * connect.c - handles connections to ssh servers

 *

 * This file is part of the SSH Library

 *

 * Copyright (c) 2003-2013 by Aris Adamantiadis

 *

 * The SSH Library is free software; you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as published by

 * the Free Software Foundation; either version 2.1 of the License, or (at your

 * option) any later version.

 *

 * The SSH Library is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public

 * License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with the SSH Library; see the file COPYING.  If not, write to

 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,

 * MA 02111-1307, USA.

 */

#include "config.h"

#include <errno.h>

#include <fcntl.h>

#include <stdbool.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#ifdef HAVE_SYS_TIME_H

#include <sys/time.h>

#endif /* HAVE_SYS_TIME_H */

#include "libssh/libssh.h"

#include "libssh/misc.h"

#ifdef _WIN32

/*

 * Only use Windows API functions available on Windows 2000 SP4 or later.

 * The available constants are in <sdkddkver.h>.

 *  http://msdn.microsoft.com/en-us/library/aa383745.aspx

 *  http://blogs.msdn.com/oldnewthing/archive/2007/04/11/2079137.aspx

 */

#undef _WIN32_WINNT

#ifdef HAVE_WSPIAPI_H

#define _WIN32_WINNT 0x0500 /* _WIN32_WINNT_WIN2K */

#undef NTDDI_VERSION

#define NTDDI_VERSION 0x05000400 /* NTDDI_WIN2KSP4 */

#else

#define _WIN32_WINNT 0x0501 /* _WIN32_WINNT_WINXP */

#undef NTDDI_VERSION

#define NTDDI_VERSION 0x05010000 /* NTDDI_WINXP */

#endif

#include <winsock2.h>

#include <ws2tcpip.h>

/* <wspiapi.h> is necessary for getaddrinfo before Windows XP, but it isn't

 * available on some platforms like MinGW. */

#ifdef HAVE_WSPIAPI_H

#include <wspiapi.h>

#endif

#ifndef EINPROGRESS

#define EINPROGRESS WSAEINPROGRESS

#endif

#else /* _WIN32 */

#include <netdb.h>

#include <sys/socket.h>

#include <sys/select.h>

#include <netinet/in.h>

#include <netinet/tcp.h>

#endif /* _WIN32 */

#include "libssh/priv.h"

#include "libssh/socket.h"

#include "libssh/channels.h"

#include "libssh/session.h"

#include "libssh/poll.h"

#ifndef HAVE_GETADDRINFO

#error "Your system must have getaddrinfo()"

#endif

#ifdef _WIN32

#ifndef gai_strerror

char WSAAPI *gai_strerrorA(int code)

{

    static char buf[256];

    snprintf(buf, sizeof(buf), "Undetermined error code (%d)", code);

    return buf;

}

#endif /* gai_strerror */

#endif /* _WIN32 */

static int ssh_connect_socket_close(socket_t s)

{

#ifdef _WIN32

    return closesocket(s);

#else

    return close(s);

#endif

}

static int

getai(const char *host, int port, int ai_family, struct addrinfo **ai)

{

    const char *service = NULL;

    struct addrinfo hints;

    char s_port[10];

    ZERO_STRUCT(hints);

    hints.ai_protocol = IPPROTO_TCP;

    hints.ai_family = ai_family;

    hints.ai_socktype = SOCK_STREAM;

    if (port == 0) {

        hints.ai_flags = AI_PASSIVE;

    } else {

        snprintf(s_port, sizeof(s_port), "%hu", (unsigned short)port);

        service = s_port;

#ifdef AI_NUMERICSERV

        hints.ai_flags = AI_NUMERICSERV;

#endif

    }

    if (ssh_is_ipaddr(host) == 1) {

        /* this is an IP address */

        SSH_LOG(SSH_LOG_PACKET, "host %s matches an IP address", host);

        hints.ai_flags |= AI_NUMERICHOST;

    }

    return getaddrinfo(host, service, &hints, ai);

}

static int set_tcp_nodelay(socket_t socket)

{

    int opt = 1;

    return setsockopt(socket,

                      IPPROTO_TCP,

                      TCP_NODELAY,

                      (void *)&opt,

                      sizeof(opt));

}

/**

 * @internal

 *

 * @brief Launches a nonblocking connect to an IPv4 or IPv6 host

 * specified by its IP address or hostname.

 *

 * @returns A file descriptor, < 0 on error.

 * @warning very ugly !!!

 */

socket_t ssh_connect_host_nonblocking(ssh_session session, const char *host,

                                      const char *bind_addr, int port)

{

    socket_t s = -1, first = -1;

    int rc;

    int ai_family;

    static const char *ai_family_str = NULL;

    struct addrinfo *ai = NULL;

    struct addrinfo *itr = NULL;

    char addrname[NI_MAXHOST], portname[NI_MAXSERV];

    switch (session->opts.address_family) {

    case SSH_ADDRESS_FAMILY_INET:

        ai_family = PF_INET;

        ai_family_str = "inet";

        break;

    case SSH_ADDRESS_FAMILY_INET6:

        ai_family = PF_INET6;

        ai_family_str = "inet6";

        break;

    case SSH_ADDRESS_FAMILY_ANY:

    default:

        ai_family = PF_UNSPEC;

        ai_family_str = "any";

    }

    SSH_LOG(SSH_LOG_PACKET,

            "Resolve target hostname %s port %d (%s)",

            host,

            port,

            ai_family_str);

    rc = getai(host, port, ai_family, &ai);

    if (rc != 0) {

        ssh_set_error(session,

                      SSH_FATAL,

                      "Failed to resolve hostname %s (%s): %s",

                      host,

                      ai_family_str,

                      gai_strerror(rc));

        return -1;

    }

    for (itr = ai; itr != NULL; itr = itr->ai_next) {

        char err_msg[SSH_ERRNO_MSG_MAX] = {0};

        /* create socket */

        s = socket(itr->ai_family, itr->ai_socktype, itr->ai_protocol);

        if (s < 0) {

            ssh_set_error(session, SSH_FATAL,

                          "Socket create failed: %s",

                          ssh_strerror(errno, err_msg, SSH_ERRNO_MSG_MAX));

            continue;

        }

        if (bind_addr) {

            struct addrinfo *bind_ai = NULL;

            struct addrinfo *bind_itr = NULL;

            SSH_LOG(SSH_LOG_PACKET,

                    "Resolving bind address %s (%s)",

                    bind_addr,

                    ai_family_str);

            rc = getai(bind_addr, 0, ai_family, &bind_ai);

            if (rc != 0) {

                ssh_set_error(session,

                              SSH_FATAL,

                              "Failed to resolve bind address %s (%s): %s",

                              bind_addr,

                              ai_family_str,

                              gai_strerror(rc));

                ssh_connect_socket_close(s);

                s = -1;

                break;

            }

            for (bind_itr = bind_ai;

                 bind_itr != NULL;

                 bind_itr = bind_itr->ai_next)

            {

                rc = bind(s, bind_itr->ai_addr, bind_itr->ai_addrlen);

                if (rc < 0) {

                    ssh_set_error(session, SSH_FATAL,

                                  "Binding local address: %s",

                                  ssh_strerror(errno, err_msg, SSH_ERRNO_MSG_MAX));

                    continue;

                } else {

                    break;

                }

            }

            freeaddrinfo(bind_ai);

            /* Cannot bind to any local addresses */

            if (bind_itr == NULL) {

                ssh_connect_socket_close(s);

                s = -1;

                continue;

            }

        }

        rc = ssh_socket_set_nonblocking(s);

        if (rc < 0) {

            ssh_set_error(session, SSH_FATAL,

                          "Failed to set socket non-blocking for %s:%d",

                          host, port);

            ssh_connect_socket_close(s);

            s = -1;

            continue;

        }

        if (session->opts.nodelay) {

            /* For winsock, socket options are only effective before connect */

            rc = set_tcp_nodelay(s);

            if (rc < 0) {

                ssh_set_error(session, SSH_FATAL,

                              "Failed to set TCP_NODELAY on socket: %s",

                              ssh_strerror(errno, err_msg, SSH_ERRNO_MSG_MAX));

                ssh_connect_socket_close(s);

                s = -1;

                continue;

            }

        }

        rc = getnameinfo(itr->ai_addr,

                         itr->ai_addrlen,

                         addrname,

                         sizeof(addrname),

                         portname,

                         sizeof(portname),

                         NI_NUMERICHOST | NI_NUMERICSERV);

        if (rc != 0) {

            ssh_set_error(session, SSH_FATAL,

                          "getnameinfo failed: %s",

                          ssh_strerror(errno, err_msg, SSH_ERRNO_MSG_MAX));

            ssh_connect_socket_close(s);

            s = -1;

            continue;

        }

        errno = 0;

        SSH_LOG(SSH_LOG_PACKET,

                "Connecting to host %s [%s] port %s",

                host,

                addrname,

                portname);

        rc = connect(s, itr->ai_addr, itr->ai_addrlen);

        if (rc == -1) {

            if ((errno != 0) && (errno != EINPROGRESS)) {

                ssh_set_error(session, SSH_FATAL,

                              "Failed to connect: %s",

                              ssh_strerror(errno, err_msg, SSH_ERRNO_MSG_MAX));

                ssh_connect_socket_close(s);

                s = -1;

            } else {

                if (first == -1) {

                    SSH_LOG(SSH_LOG_PACKET, "EINPROGRESS => Store for later.");

                    first = s;

                } else { /* errno == EINPROGRESS */

                    /* save only the first "working" socket */

                    ssh_connect_socket_close(s);

                    s = -1;

                }

            }

            continue;

        }

        break;

    }

    freeaddrinfo(ai);

    /* first let's go through all the addresses looking for immediate

     * connection, otherwise return the first address without error or error */

    if (s == -1) {

        s = first;

    } else if (s != first && first != -1) {

        /* Clean up the saved socket if any */

        ssh_connect_socket_close(first);

    }

    return s;

}

/**

 * @addtogroup libssh_session

 *

 * @{

 */

static int ssh_select_cb (socket_t fd, int revents, void *userdata)

{

    fd_set *set = (fd_set *)userdata;

    if (revents & POLLIN) {

        FD_SET(fd, set);

    }

    return 0;

}

/**

 * @brief A wrapper for the select syscall

 *

 * This function acts more or less like the select(2) syscall.\n

 * There is no support for writing or exceptions.\n

 *

 * @param[in]  channels Arrays of channels pointers terminated by a NULL.

 *                      It is never rewritten.

 *

 * @param[out] outchannels Arrays of the same size as "channels", there is no

 *                         need to initialize it.

 *

 * @param[in]  maxfd    Maximum +1 file descriptor from readfds.

 *

 * @param[in]  readfds  A fd_set of file descriptors to be select'ed for

 *                      reading.

 *

 * @param[in]  timeout  The timeout in milliseconds.

 *

 * @return              SSH_OK on success,

 *                      SSH_ERROR on error,

 *                      SSH_EINTR if it was interrupted. In that case,

 *                      just restart it.

 *

 * @warning libssh is not reentrant here. That means that if a signal is caught

 *          during the processing of this function, you cannot call libssh

 *          functions on sessions that are busy with ssh_select().

 *

 * @see select(2)

 */

int ssh_select(ssh_channel *channels, ssh_channel *outchannels, socket_t maxfd,

               fd_set *readfds, struct timeval *timeout)

{

    fd_set origfds;

    socket_t fd;

    size_t i, j;

    int rc;

    int base_tm, tm;

    struct ssh_timestamp ts;

    ssh_event event = ssh_event_new();

    int firstround = 1;

    base_tm = tm = (timeout->tv_sec * 1000) + (timeout->tv_usec / 1000);

    for (i = 0 ; channels[i] != NULL; ++i) {

        ssh_event_add_session(event, channels[i]->session);

    }

    ZERO_STRUCT(origfds);

    FD_ZERO(&origfds);

    for (fd = 0; fd < maxfd ; fd++) {

        if (FD_ISSET(fd, readfds)) {

            ssh_event_add_fd(event, fd, POLLIN, ssh_select_cb, readfds);

            FD_SET(fd, &origfds);

        }

    }

    outchannels[0] = NULL;

    FD_ZERO(readfds);

    ssh_timestamp_init(&ts);

    do {

        /* Poll every channel */

        j = 0;

        for (i = 0; channels[i]; i++) {

            rc = ssh_channel_poll(channels[i], 0);

            if (rc != 0) {

                outchannels[j] = channels[i];

                j++;

            } else {

                rc = ssh_channel_poll(channels[i], 1);

                if (rc != 0) {

                    outchannels[j] = channels[i];

                    j++;

                }

            }

        }

        outchannels[j] = NULL;

        if (j != 0) {

            break;

        }

        /* watch if a user socket was triggered */

        for (fd = 0; fd < maxfd; fd++) {

            if (FD_ISSET(fd, readfds)) {

                goto out;

            }

        }

        /* If the timeout is elapsed, we should go out */

        if (!firstround && ssh_timeout_elapsed(&ts, base_tm)) {

            goto out;

        }

        /* since there's nothing, let's fire the polling */

        rc = ssh_event_dopoll(event,tm);

        if (rc == SSH_ERROR) {

            goto out;

        }

        tm = ssh_timeout_update(&ts, base_tm);

        firstround = 0;

    } while (1);

out:

    for (fd = 0; fd < maxfd; fd++) {

        if (FD_ISSET(fd, &origfds)) {

            ssh_event_remove_fd(event, fd);

        }

    }

    ssh_event_free(event);

    return SSH_OK;

}

/** @} */