Add a direct-tcpip example which shows local port forwarding
This commit is contained in:
Peter Stuge
parent
f70dbfa3e6
commit
bd0505d6b9
1
example/.gitignore
vendored
1
example/.gitignore
vendored
@ -2,6 +2,7 @@ Makefile
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Makefile.in
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*.gcno
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*.gcda
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direct_tcpip
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scp
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scp_nonblock
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scp_write
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@ -1,7 +1,7 @@
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AUTOMAKE_OPTIONS = foreign nostdinc
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# samples
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noinst_PROGRAMS = ssh2 \
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noinst_PROGRAMS = direct_tcpip ssh2 \
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scp scp_nonblock \
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scp_write scp_write_nonblock \
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sftp sftp_nonblock \
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274
example/direct_tcpip.c
Normal file
274
example/direct_tcpip.c
Normal file
@ -0,0 +1,274 @@
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#include <libssh2.h>
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#ifdef HAVE_WINSOCK2_H
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# include <winsock2.h>
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#endif
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#ifdef HAVE_SYS_SOCKET_H
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# include <sys/socket.h>
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#endif
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#ifdef HAVE_NETINET_IN_H
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# include <netinet/in.h>
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#endif
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# ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#ifdef HAVE_ARPA_INET_H
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# include <arpa/inet.h>
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#endif
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#ifdef HAVE_SYS_TIME_H
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# include <sys/time.h>
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#endif
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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const char *keyfile1 = "/home/username/.ssh/id_rsa.pub";
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const char *keyfile2 = "/home/username/.ssh/id_rsa";
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const char *username = "username";
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const char *password = "";
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const char *server_ip = "127.0.0.1";
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const char *local_listenip = "127.0.0.1";
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unsigned int local_listenport = 2222;
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const char *remote_desthost = "localhost"; /* resolved by the server */
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unsigned int remote_destport = 22;
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enum {
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AUTH_NONE = 0,
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AUTH_PASSWORD,
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AUTH_PUBLICKEY
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};
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int main(int argc, char *argv[])
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{
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int rc, sock = -1, listensock = -1, forwardsock = -1, i, auth = AUTH_NONE;
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struct sockaddr_in sin;
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socklen_t sinlen;
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const char *fingerprint;
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char *userauthlist;
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LIBSSH2_SESSION *session;
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LIBSSH2_CHANNEL *channel = NULL;
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const char *shost;
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unsigned int sport;
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fd_set fds;
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struct timeval tv;
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ssize_t len, wr;
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char buf[16384];
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#ifdef WIN32
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WSADATA wsadata;
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WSAStartup(MAKEWORD(2,0), &wsadata);
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#endif
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if (argc > 1)
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server_ip = argv[1];
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if (argc > 2)
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username = argv[2];
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if (argc > 3)
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password = argv[3];
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if (argc > 4)
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local_listenip = argv[4];
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if (argc > 5)
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local_listenport = atoi(argv[5]);
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if (argc > 6)
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remote_desthost = argv[6];
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if (argc > 7)
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remote_destport = atoi(argv[7]);
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/* Connect to SSH server */
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sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
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sin.sin_family = AF_INET;
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if (-1 == inet_aton(server_ip, &sin.sin_addr)) {
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perror("inet_aton");
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return -1;
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}
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sin.sin_port = htons(22);
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if (connect(sock, (struct sockaddr*)(&sin),
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sizeof(struct sockaddr_in)) != 0) {
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fprintf(stderr, "failed to connect!\n");
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return -1;
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}
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/* Create a session instance */
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session = libssh2_session_init();
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if(!session) {
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fprintf(stderr, "Could not initialize SSH session!\n");
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return -1;
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}
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/* ... start it up. This will trade welcome banners, exchange keys,
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* and setup crypto, compression, and MAC layers
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*/
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rc = libssh2_session_startup(session, sock);
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if(rc) {
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fprintf(stderr, "Error when starting up SSH session: %d\n", rc);
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return -1;
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}
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/* At this point we havn't yet authenticated. The first thing to do
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* is check the hostkey's fingerprint against our known hosts Your app
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* may have it hard coded, may go to a file, may present it to the
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* user, that's your call
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*/
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fingerprint = libssh2_hostkey_hash(session, LIBSSH2_HOSTKEY_HASH_MD5);
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fprintf(stderr, "Fingerprint: ");
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for(i = 0; i < 16; i++)
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fprintf(stderr, "%02X ", (unsigned char)fingerprint[i]);
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fprintf(stderr, "\n");
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/* check what authentication methods are available */
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userauthlist = libssh2_userauth_list(session, username, strlen(username));
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printf("Authentication methods: %s\n", userauthlist);
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if (strstr(userauthlist, "password"))
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auth |= AUTH_PASSWORD;
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if (strstr(userauthlist, "publickey"))
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auth |= AUTH_PUBLICKEY;
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/* check for options */
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if(argc > 8) {
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if ((auth & AUTH_PASSWORD) && !strcasecmp(argv[8], "-p"))
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auth = AUTH_PASSWORD;
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if ((auth & AUTH_PUBLICKEY) && !strcasecmp(argv[8], "-k"))
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auth = AUTH_PUBLICKEY;
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}
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if (auth & AUTH_PASSWORD) {
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if (libssh2_userauth_password(session, username, password)) {
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fprintf(stderr, "Authentication by password failed.\n");
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goto shutdown;
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}
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} else if (auth & AUTH_PUBLICKEY) {
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if (libssh2_userauth_publickey_fromfile(session, username, keyfile1, keyfile2, password)) {
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printf("\tAuthentication by public key failed!\n");
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goto shutdown;
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}
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printf("\tAuthentication by public key succeeded.\n");
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} else {
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printf("No supported authentication methods found!\n");
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goto shutdown;
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}
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listensock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
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sin.sin_family = AF_INET;
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sin.sin_port = htons(local_listenport);
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if (-1 == inet_aton(local_listenip, &sin.sin_addr)) {
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perror("inet_aton");
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goto shutdown;
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}
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i = 1;
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setsockopt(listensock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
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sinlen=sizeof(sin);
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if (-1 == bind(listensock, (struct sockaddr *)&sin, sinlen)) {
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perror("bind");
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goto shutdown;
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}
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if (-1 == listen(listensock, 2)) {
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perror("listen");
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goto shutdown;
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}
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printf("Waiting for TCP connection on %s:%d...\n",
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inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
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forwardsock = accept(listensock, (struct sockaddr *)&sin, &sinlen);
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if (-1 == forwardsock) {
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perror("accept");
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goto shutdown;
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}
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shost = inet_ntoa(sin.sin_addr);
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sport = ntohs(sin.sin_port);
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printf("Forwarding connection from %s:%d here to remote %s:%d\n", shost,
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sport, remote_desthost, remote_destport);
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channel = libssh2_channel_direct_tcpip_ex(session, remote_desthost,
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remote_destport, shost, sport);
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if (!channel) {
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fprintf(stderr, "Could not open the direct-tcpip channel!\n");
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fprintf(stderr, "(Note that this can be a problem at the server! Please review the server logs.)\n");
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goto shutdown;
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}
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/* Must use non-blocking IO hereafter due to the current libssh2 API */
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libssh2_session_set_blocking(session, 0);
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while (1) {
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FD_ZERO(&fds);
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FD_SET(forwardsock, &fds);
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tv.tv_sec = 0;
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tv.tv_usec = 100000;
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rc = select(forwardsock + 1, &fds, NULL, NULL, &tv);
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if (-1 == rc) {
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perror("select");
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goto shutdown;
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}
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if (rc && FD_ISSET(forwardsock, &fds)) {
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len = read(forwardsock, buf, sizeof(buf));
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if (len < 0) {
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perror("read");
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goto shutdown;
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} else if (0 == len) {
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printf("The client at %s:%d disconnected!\n", shost, sport);
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goto shutdown;
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}
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wr = 0;
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do {
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i = libssh2_channel_write(channel, buf, len);
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if (i < 0) {
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fprintf(stderr, "libssh2_channel_write: %d\n", i);
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goto shutdown;
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}
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wr += i;
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} while(i > 0 && wr < len);
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}
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while (1) {
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len = libssh2_channel_read(channel, buf, sizeof(buf));
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if (LIBSSH2_ERROR_EAGAIN == len)
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break;
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else if (len < 0) {
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fprintf(stderr, "libssh2_channel_read: %d", len);
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goto shutdown;
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}
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wr = 0;
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while (wr < len) {
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i = write(forwardsock, buf + wr, len - wr);
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if (i <= 0) {
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perror("write");
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goto shutdown;
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}
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wr += i;
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}
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}
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}
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shutdown:
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#ifdef WIN32
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closesocket(forwardsock);
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closesocket(listensock);
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#else
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close(forwardsock);
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close(listensock);
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#endif
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if (channel)
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libssh2_channel_free(channel);
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libssh2_session_disconnect(session, "Client disconnecting normally");
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libssh2_session_free(session);
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#ifdef WIN32
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closesocket(sock);
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#else
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close(sock);
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#endif
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return 0;
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}
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