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8a7232be6108245bf4b49dba4b74d4a063bdf8bc
libssh2/example/tcpip-forward.c
Alexander Lamaison 6bf8983368 CMake build system. 
Tested:
 - Windows:
    - Visual C++ 2005/2008/2010/2012/2013/MinGW-w64
    - static/shared
    - 32/64-bit
    - OpenSSL/WinCNG
    - Without zlib
 - Linux:
    - GCC 4.6.3/Clang 3.4
    - static/shared
    - 32/64-bit
    - OpenSSL/Libgcrypt
    - With/Without zlib
 - MacOS X
    - AppleClang 6.0.0
    - static
    - 64-bit
    - OpenSSL
    - Without zlib

Conflicts:
	README
2015-03-12 22:48:38 +00:00

324 lines
9.1 KiB
C
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#include "libssh2_config.h"
#include <libssh2.h>
#ifdef WIN32
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#else
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#endif
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <sys/types.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#ifndef INADDR_NONE
#define INADDR_NONE (in_addr_t)-1
#endif
const char *keyfile1 = "/home/username/.ssh/id_rsa.pub";
const char *keyfile2 = "/home/username/.ssh/id_rsa";
const char *username = "username";
const char *password = "";
const char *server_ip = "127.0.0.1";
const char *remote_listenhost = "localhost"; /* resolved by the server */
int remote_wantport = 2222;
int remote_listenport;
const char *local_destip = "127.0.0.1";
int local_destport = 22;
enum {
AUTH_NONE = 0,
AUTH_PASSWORD,
AUTH_PUBLICKEY
};
int main(int argc, char *argv[])
{
int rc, i, auth = AUTH_NONE;
struct sockaddr_in sin;
socklen_t sinlen = sizeof(sin);
const char *fingerprint;
char *userauthlist;
LIBSSH2_SESSION *session;
LIBSSH2_LISTENER *listener = NULL;
LIBSSH2_CHANNEL *channel = NULL;
fd_set fds;
struct timeval tv;
ssize_t len, wr;
char buf[16384];
#ifdef WIN32
SOCKET sock = INVALID_SOCKET, forwardsock = INVALID_SOCKET;
WSADATA wsadata;
int err;
err = WSAStartup(MAKEWORD(2,0), &wsadata);
if (err != 0) {
fprintf(stderr, "WSAStartup failed with error: %d\n", err);
return 1;
}
#else
int sock = -1, forwardsock = -1;
#endif
if (argc > 1)
server_ip = argv[1];
if (argc > 2)
username = argv[2];
if (argc > 3)
password = argv[3];
if (argc > 4)
remote_listenhost = argv[4];
if (argc > 5)
remote_wantport = atoi(argv[5]);
if (argc > 6)
local_destip = argv[6];
if (argc > 7)
local_destport = atoi(argv[7]);
rc = libssh2_init (0);
if (rc != 0) {
fprintf (stderr, "libssh2 initialization failed (%d)\n", rc);
return 1;
}
/* Connect to SSH server */
sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
#ifdef WIN32
if (sock == INVALID_SOCKET) {
fprintf(stderr, "failed to open socket!\n");
return -1;
}
#else
if (sock == -1) {
perror("socket");
return -1;
}
#endif
sin.sin_family = AF_INET;
if (INADDR_NONE == (sin.sin_addr.s_addr = inet_addr(server_ip))) {
perror("inet_addr");
return -1;
}
sin.sin_port = htons(22);
if (connect(sock, (struct sockaddr*)(&sin),
sizeof(struct sockaddr_in)) != 0) {
fprintf(stderr, "failed to connect!\n");
return -1;
}
/* Create a session instance */
session = libssh2_session_init();
if(!session) {
fprintf(stderr, "Could not initialize SSH session!\n");
return -1;
}
/* ... start it up. This will trade welcome banners, exchange keys,
* and setup crypto, compression, and MAC layers
*/
rc = libssh2_session_handshake(session, sock);
if(rc) {
fprintf(stderr, "Error when starting up SSH session: %d\n", rc);
return -1;
}
/* At this point we havn't yet authenticated. The first thing to do
* is check the hostkey's fingerprint against our known hosts Your app
* may have it hard coded, may go to a file, may present it to the
* user, that's your call
*/
fingerprint = libssh2_hostkey_hash(session, LIBSSH2_HOSTKEY_HASH_SHA1);
fprintf(stderr, "Fingerprint: ");
for(i = 0; i < 20; i++)
fprintf(stderr, "%02X ", (unsigned char)fingerprint[i]);
fprintf(stderr, "\n");
/* check what authentication methods are available */
userauthlist = libssh2_userauth_list(session, username, strlen(username));
fprintf(stderr, "Authentication methods: %s\n", userauthlist);
if (strstr(userauthlist, "password"))
auth |= AUTH_PASSWORD;
if (strstr(userauthlist, "publickey"))
auth |= AUTH_PUBLICKEY;
/* check for options */
if(argc > 8) {
if ((auth & AUTH_PASSWORD) && !strcasecmp(argv[8], "-p"))
auth = AUTH_PASSWORD;
if ((auth & AUTH_PUBLICKEY) && !strcasecmp(argv[8], "-k"))
auth = AUTH_PUBLICKEY;
}
if (auth & AUTH_PASSWORD) {
if (libssh2_userauth_password(session, username, password)) {
fprintf(stderr, "Authentication by password failed.\n");
goto shutdown;
}
} else if (auth & AUTH_PUBLICKEY) {
if (libssh2_userauth_publickey_fromfile(session, username, keyfile1,
keyfile2, password)) {
fprintf(stderr, "\tAuthentication by public key failed!\n");
goto shutdown;
}
fprintf(stderr, "\tAuthentication by public key succeeded.\n");
} else {
fprintf(stderr, "No supported authentication methods found!\n");
goto shutdown;
}
fprintf(stderr, "Asking server to listen on remote %s:%d\n",
remote_listenhost, remote_wantport);
listener = libssh2_channel_forward_listen_ex(session, remote_listenhost,
remote_wantport, &remote_listenport, 1);
if (!listener) {
fprintf(stderr, "Could not start the tcpip-forward listener!\n"
"(Note that this can be a problem at the server!"
" Please review the server logs.)\n");
goto shutdown;
}
fprintf(stderr, "Server is listening on %s:%d\n", remote_listenhost,
remote_listenport);
fprintf(stderr, "Waiting for remote connection\n");
channel = libssh2_channel_forward_accept(listener);
if (!channel) {
fprintf(stderr, "Could not accept connection!\n"
"(Note that this can be a problem at the server!"
" Please review the server logs.)\n");
goto shutdown;
}
fprintf(stderr,
"Accepted remote connection. Connecting to local server %s:%d\n",
local_destip, local_destport);
forwardsock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
#ifdef WIN32
if (forwardsock == INVALID_SOCKET) {
fprintf(stderr, "failed to open forward socket!\n");
goto shutdown;
}
#else
if (forwardsock == -1) {
perror("socket");
goto shutdown;
}
#endif
sin.sin_family = AF_INET;
sin.sin_port = htons(local_destport);
if (INADDR_NONE == (sin.sin_addr.s_addr = inet_addr(local_destip))) {
perror("inet_addr");
goto shutdown;
}
if (-1 == connect(forwardsock, (struct sockaddr *)&sin, sinlen)) {
perror("connect");
goto shutdown;
}
fprintf(stderr, "Forwarding connection from remote %s:%d to local %s:%d\n",
remote_listenhost, remote_listenport, local_destip, local_destport);
/* Must use non-blocking IO hereafter due to the current libssh2 API */
libssh2_session_set_blocking(session, 0);
while (1) {
FD_ZERO(&fds);
FD_SET(forwardsock, &fds);
tv.tv_sec = 0;
tv.tv_usec = 100000;
rc = select(forwardsock + 1, &fds, NULL, NULL, &tv);
if (-1 == rc) {
perror("select");
goto shutdown;
}
if (rc && FD_ISSET(forwardsock, &fds)) {
len = recv(forwardsock, buf, sizeof(buf), 0);
if (len < 0) {
perror("read");
goto shutdown;
} else if (0 == len) {
fprintf(stderr, "The local server at %s:%d disconnected!\n",
local_destip, local_destport);
goto shutdown;
}
wr = 0;
do {
i = libssh2_channel_write(channel, buf, len);
if (i < 0) {
fprintf(stderr, "libssh2_channel_write: %d\n", i);
goto shutdown;
}
wr += i;
} while(i > 0 && wr < len);
}
while (1) {
len = libssh2_channel_read(channel, buf, sizeof(buf));
if (LIBSSH2_ERROR_EAGAIN == len)
break;
else if (len < 0) {
fprintf(stderr, "libssh2_channel_read: %d", (int)len);
goto shutdown;
}
wr = 0;
while (wr < len) {
i = send(forwardsock, buf + wr, len - wr, 0);
if (i <= 0) {
perror("write");
goto shutdown;
}
wr += i;
}
if (libssh2_channel_eof(channel)) {
fprintf(stderr, "The remote client at %s:%d disconnected!\n",
remote_listenhost, remote_listenport);
goto shutdown;
}
}
}
shutdown:
#ifdef WIN32
closesocket(forwardsock);
#else
close(forwardsock);
#endif
if (channel)
libssh2_channel_free(channel);
if (listener)
libssh2_channel_forward_cancel(listener);
libssh2_session_disconnect(session, "Client disconnecting normally");
libssh2_session_free(session);
#ifdef WIN32
closesocket(sock);
#else
close(sock);
#endif
libssh2_exit();
return 0;
}
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