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Diffstat (limited to 'libssh/src/connect.c')
-rw-r--r-- | libssh/src/connect.c | 484 |
1 files changed, 484 insertions, 0 deletions
diff --git a/libssh/src/connect.c b/libssh/src/connect.c new file mode 100644 index 00000000..ae55b140 --- /dev/null +++ b/libssh/src/connect.c @@ -0,0 +1,484 @@ +/* + * connect.c - handles connections to ssh servers + * + * This file is part of the SSH Library + * + * Copyright (c) 2003-2009 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 <stdio.h> +#include <stdlib.h> +#include <string.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 + +#if _MSC_VER >= 1400 +#include <io.h> +#undef close +#define close _close +#endif /* _MSC_VER */ +#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 + +#else /* _WIN32 */ + +#include <netdb.h> +#include <sys/socket.h> +#include <sys/select.h> +#include <netinet/in.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(ssh_session session, const char *host, int port, 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 = PF_UNSPEC; + 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)) { + /* this is an IP address */ + ssh_log(session,SSH_LOG_PACKET,"host %s matches an IP address",host); + hints.ai_flags |= AI_NUMERICHOST; + } + + return getaddrinfo(host, service, &hints, ai); +} + +static int ssh_connect_ai_timeout(ssh_session session, const char *host, + int port, struct addrinfo *ai, long timeout, long usec, socket_t s) { + int timeout_ms; + ssh_pollfd_t fds; + int rc = 0; + socklen_t len = sizeof(rc); + + enter_function(); + + /* I know we're losing some precision. But it's not like poll-like family + * type of mechanisms are precise up to the microsecond. + */ + timeout_ms=timeout * 1000 + usec / 1000; + + ssh_socket_set_nonblocking(s); + + ssh_log(session, SSH_LOG_RARE, "Trying to connect to host: %s:%d with " + "timeout %d ms", host, port, timeout_ms); + + /* The return value is checked later */ + connect(s, ai->ai_addr, ai->ai_addrlen); + freeaddrinfo(ai); + + fds.fd=s; + fds.revents=0; + fds.events=POLLOUT; +#ifdef _WIN32 + fds.events |= POLLWRNORM; +#endif + rc = ssh_poll(&fds,1,timeout_ms); + + if (rc == 0) { + /* timeout */ + ssh_set_error(session, SSH_FATAL, + "Timeout while connecting to %s:%d", host, port); + ssh_connect_socket_close(s); + leave_function(); + return -1; + } + + if (rc < 0) { + ssh_set_error(session, SSH_FATAL, + "poll error: %s", strerror(errno)); + ssh_connect_socket_close(s); + leave_function(); + return -1; + } + rc = 0; + + /* Get connect(2) return code. Zero means no error */ + getsockopt(s, SOL_SOCKET, SO_ERROR,(char *) &rc, &len); + if (rc != 0) { + ssh_set_error(session, SSH_FATAL, + "Connect to %s:%d failed: %s", host, port, strerror(rc)); + ssh_connect_socket_close(s); + leave_function(); + return -1; + } + + /* s is connected ? */ + ssh_log(session, SSH_LOG_PACKET, "Socket connected with timeout\n"); + ssh_socket_set_blocking(s); + + leave_function(); + return s; +} + +/** + * @internal + * + * @brief Connect to an IPv4 or IPv6 host specified by its IP address or + * hostname. + * + * @returns A file descriptor, < 0 on error. + */ +socket_t ssh_connect_host(ssh_session session, const char *host, + const char *bind_addr, int port, long timeout, long usec) { + socket_t s = -1; + int rc; + struct addrinfo *ai; + struct addrinfo *itr; + + enter_function(); + + rc = getai(session,host, port, &ai); + if (rc != 0) { + ssh_set_error(session, SSH_FATAL, + "Failed to resolve hostname %s (%s)", host, gai_strerror(rc)); + leave_function(); + return -1; + } + + for (itr = ai; itr != NULL; itr = itr->ai_next){ + /* 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", strerror(errno)); + continue; + } + + if (bind_addr) { + struct addrinfo *bind_ai; + struct addrinfo *bind_itr; + + ssh_log(session, SSH_LOG_PACKET, "Resolving %s\n", bind_addr); + + rc = getai(session,bind_addr, 0, &bind_ai); + if (rc != 0) { + ssh_set_error(session, SSH_FATAL, + "Failed to resolve bind address %s (%s)", + bind_addr, + gai_strerror(rc)); + freeaddrinfo(ai); + close(s); + leave_function(); + return -1; + } + + for (bind_itr = bind_ai; bind_itr != NULL; bind_itr = bind_itr->ai_next) { + if (bind(s, bind_itr->ai_addr, bind_itr->ai_addrlen) < 0) { + ssh_set_error(session, SSH_FATAL, + "Binding local address: %s", strerror(errno)); + continue; + } else { + break; + } + } + freeaddrinfo(bind_ai); + + /* Cannot bind to any local addresses */ + if (bind_itr == NULL) { + ssh_connect_socket_close(s); + s = -1; + continue; + } + } + + if (timeout || usec) { + socket_t ret = ssh_connect_ai_timeout(session, host, port, itr, + timeout, usec, s); + leave_function(); + return ret; + } + + if (connect(s, itr->ai_addr, itr->ai_addrlen) < 0) { + ssh_set_error(session, SSH_FATAL, "Connect failed: %s", strerror(errno)); + ssh_connect_socket_close(s); + s = -1; + leave_function(); + continue; + } else { + /* We are connected */ + break; + } + } + + freeaddrinfo(ai); + leave_function(); + + return s; +} + +/** + * @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; + int rc; + struct addrinfo *ai; + struct addrinfo *itr; + + enter_function(); + + rc = getai(session,host, port, &ai); + if (rc != 0) { + ssh_set_error(session, SSH_FATAL, + "Failed to resolve hostname %s (%s)", host, gai_strerror(rc)); + leave_function(); + return -1; + } + + for (itr = ai; itr != NULL; itr = itr->ai_next){ + /* 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", strerror(errno)); + continue; + } + + if (bind_addr) { + struct addrinfo *bind_ai; + struct addrinfo *bind_itr; + + ssh_log(session, SSH_LOG_PACKET, "Resolving %s\n", bind_addr); + + rc = getai(session,bind_addr, 0, &bind_ai); + if (rc != 0) { + ssh_set_error(session, SSH_FATAL, + "Failed to resolve bind address %s (%s)", + bind_addr, + gai_strerror(rc)); + close(s); + s=-1; + break; + } + + for (bind_itr = bind_ai; bind_itr != NULL; bind_itr = bind_itr->ai_next) { + if (bind(s, bind_itr->ai_addr, bind_itr->ai_addrlen) < 0) { + ssh_set_error(session, SSH_FATAL, + "Binding local address: %s", strerror(errno)); + continue; + } else { + break; + } + } + freeaddrinfo(bind_ai); + + /* Cannot bind to any local addresses */ + if (bind_itr == NULL) { + ssh_connect_socket_close(s); + s = -1; + continue; + } + } + ssh_socket_set_nonblocking(s); + + connect(s, itr->ai_addr, itr->ai_addrlen); + break; + } + + freeaddrinfo(ai); + leave_function(); + + 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 functions 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 same size that "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 A timeout for the select. + * + * @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) { + int 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); + } + for (i=0; i<maxfd ; ++i){ + if(FD_ISSET(i, readfds)){ + ssh_event_add_fd(event, i, POLLIN, ssh_select_cb, readfds); + } + } + outchannels[0] = NULL; + FD_ZERO(readfds); + ssh_timestamp_init(&ts); + do { + /* Poll every channel */ + j = 0; + for (i = 0; channels[i]; i++) { + if(ssh_channel_poll(channels[i], 0) != 0) { + outchannels[j] = channels[i]; + j++; + } else if(ssh_channel_poll(channels[i], 1) != 0) { + outchannels[j] = channels[i]; + j++; + } + } + outchannels[j] = NULL; + if(j != 0) + break; + /* watch if a user socket was triggered */ + for(i = 0;i<maxfd;++i) + if(FD_ISSET(i, 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){ + ssh_event_free(event); + return SSH_ERROR; + } + tm = ssh_timeout_update(&ts, base_tm); + firstround=0; + } while (1); +out: + ssh_event_free(event); + return SSH_OK; +} + +/** @} */ + +/* vim: set ts=4 sw=4 et cindent: */ |