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-rw-r--r--networking/Makefile.in1
-rw-r--r--networking/config.in1
-rw-r--r--networking/telnetd.c538
3 files changed, 540 insertions, 0 deletions
diff --git a/networking/Makefile.in b/networking/Makefile.in
index 425b5d3..510c811 100644
--- a/networking/Makefile.in
+++ b/networking/Makefile.in
@@ -32,6 +32,7 @@ NETWORKING-$(CONFIG_PING) += ping.o
NETWORKING-$(CONFIG_PING6) += ping6.o
NETWORKING-$(CONFIG_ROUTE) += route.o
NETWORKING-$(CONFIG_TELNET) += telnet.o
+NETWORKING-$(CONFIG_TELNETD) += telnetd.o
NETWORKING-$(CONFIG_TFTP) += tftp.o
NETWORKING-$(CONFIG_TRACEROUTE) += traceroute.o
NETWORKING-$(CONFIG_UDHCPC) += udhcpc.o
diff --git a/networking/config.in b/networking/config.in
index bc11d83..4438a8c 100644
--- a/networking/config.in
+++ b/networking/config.in
@@ -34,6 +34,7 @@ bool 'telnet' CONFIG_TELNET
if [ "$CONFIG_TELNET" = "y" ]; then
bool ' Pass TERM type to remote host' CONFIG_FEATURE_TELNET_TTYPE
fi
+bool 'telnetd' CONFIG_TELNETD
bool 'tftp' CONFIG_TFTP
if [ "$CONFIG_TFTP" = "y" ]; then
bool ' Enable "get" command' CONFIG_FEATURE_TFTP_GET
diff --git a/networking/telnetd.c b/networking/telnetd.c
new file mode 100644
index 0000000..edc018a
--- /dev/null
+++ b/networking/telnetd.c
@@ -0,0 +1,538 @@
+/* $Id: telnetd.c,v 1.1 2002/09/30 20:52:04 andersen Exp $
+ *
+ * Simple telnet server
+ * Bjorn Wesen, Axis Communications AB (bjornw@axis.com)
+ *
+ * This file is distributed under the Gnu Public License (GPL),
+ * please see the file LICENSE for further information.
+ *
+ * ---------------------------------------------------------------------------
+ * (C) Copyright 2000, Axis Communications AB, LUND, SWEDEN
+ ****************************************************************************
+ *
+ * The telnetd manpage says it all:
+ *
+ * Telnetd operates by allocating a pseudo-terminal device (see pty(4)) for
+ * a client, then creating a login process which has the slave side of the
+ * pseudo-terminal as stdin, stdout, and stderr. Telnetd manipulates the
+ * master side of the pseudo-terminal, implementing the telnet protocol and
+ * passing characters between the remote client and the login process.
+ *
+ * Vladimir Oleynik <dzo@simtreas.ru> 2001
+ * Set process group corrections, initial busybox port
+ */
+
+/*#define DEBUG 1 */
+
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <netinet/in.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <signal.h>
+#include <termios.h>
+#ifdef DEBUG
+#define TELCMDS
+#define TELOPTS
+#endif
+#include <arpa/telnet.h>
+#include <ctype.h>
+#include <sys/syslog.h>
+
+#include "busybox.h"
+
+#define BUFSIZE 4000
+
+static const char *loginpath = "/bin/sh";
+
+/* shell name and arguments */
+
+static const char *argv_init[] = {NULL, NULL};
+
+/* structure that describes a session */
+
+struct tsession {
+ struct tsession *next;
+ int sockfd, ptyfd;
+ int shell_pid;
+ /* two circular buffers */
+ char *buf1, *buf2;
+ int rdidx1, wridx1, size1;
+ int rdidx2, wridx2, size2;
+};
+
+/*
+
+ This is how the buffers are used. The arrows indicate the movement
+ of data.
+
+ +-------+ wridx1++ +------+ rdidx1++ +----------+
+ | | <-------------- | buf1 | <-------------- | |
+ | | size1-- +------+ size1++ | |
+ | pty | | socket |
+ | | rdidx2++ +------+ wridx2++ | |
+ | | --------------> | buf2 | --------------> | |
+ +-------+ size2++ +------+ size2-- +----------+
+
+ Each session has got two buffers.
+
+*/
+
+static int maxfd;
+
+static struct tsession *sessions;
+
+
+/*
+
+ Remove all IAC's from the buffer pointed to by bf (recieved IACs are ignored
+ and must be removed so as to not be interpreted by the terminal). Make an
+ uninterrupted string of characters fit for the terminal. Do this by packing
+ all characters meant for the terminal sequentially towards the end of bf.
+
+ Return a pointer to the beginning of the characters meant for the terminal.
+ and make *num_totty the number of characters that should be sent to
+ the terminal.
+
+ Note - If an IAC (3 byte quantity) starts before (bf + len) but extends
+ past (bf + len) then that IAC will be left unprocessed and *processed will be
+ less than len.
+
+ FIXME - if we mean to send 0xFF to the terminal then it will be escaped,
+ what is the escape character? We aren't handling that situation here.
+
+ */
+static char *
+remove_iacs(struct tsession *ts, int *pnum_totty) {
+ unsigned char *ptr0 = ts->buf1 + ts->wridx1;
+ unsigned char *ptr = ptr0;
+ unsigned char *totty = ptr;
+ unsigned char *end = ptr + MIN(BUFSIZE - ts->wridx1, ts->size1);
+ int processed;
+ int num_totty;
+
+ while (ptr < end) {
+ if (*ptr != IAC) {
+ *totty++ = *ptr++;
+ }
+ else {
+ if ((ptr+2) < end) {
+ /* the entire IAC is contained in the buffer
+ we were asked to process. */
+#ifdef DEBUG
+ fprintf(stderr, "Ignoring IAC %s,%s\n",
+ *ptr, TELCMD(*(ptr+1)), TELOPT(*(ptr+2)));
+#endif
+ ptr += 3;
+ } else {
+ /* only the beginning of the IAC is in the
+ buffer we were asked to process, we can't
+ process this char. */
+ break;
+ }
+ }
+ }
+
+ processed = ptr - ptr0;
+ num_totty = totty - ptr0;
+ /* the difference between processed and num_to tty
+ is all the iacs we removed from the stream.
+ Adjust buf1 accordingly. */
+ ts->wridx1 += processed - num_totty;
+ ts->size1 -= processed - num_totty;
+ *pnum_totty = num_totty;
+ /* move the chars meant for the terminal towards the end of the
+ buffer. */
+ return memmove(ptr - num_totty, ptr0, num_totty);
+}
+
+
+static int
+getpty(char *line)
+{
+ int p;
+#ifdef HAVE_DEVPTS_FS
+ p = open("/dev/ptmx", 2);
+ if (p > 0) {
+ grantpt(p);
+ unlockpt(p);
+ strcpy(line, ptsname(p));
+ return(p);
+ }
+#else
+ struct stat stb;
+ int i;
+ int j;
+
+ strcpy(line, "/dev/ptyXX");
+
+ for (i = 0; i < 16; i++) {
+ line[8] = "pqrstuvwxyzabcde"[i];
+ line[9] = '0';
+ if (stat(line, &stb) < 0) {
+ continue;
+ }
+ for (j = 0; j < 16; j++) {
+ line[9] = j < 10 ? j + '0' : j - 10 + 'a';
+ if ((p = open(line, O_RDWR | O_NOCTTY)) >= 0) {
+ line[5] = 't';
+ return p;
+ }
+ }
+ }
+#endif /* HAVE_DEVPTS_FS */
+ return -1;
+}
+
+
+static void
+send_iac(struct tsession *ts, unsigned char command, int option)
+{
+ /* We rely on that there is space in the buffer for now. */
+ char *b = ts->buf2 + ts->rdidx2;
+ *b++ = IAC;
+ *b++ = command;
+ *b++ = option;
+ ts->rdidx2 += 3;
+ ts->size2 += 3;
+}
+
+
+static struct tsession *
+make_new_session(int sockfd)
+{
+ struct termios termbuf;
+ int pty, pid;
+ char tty_name[32];
+ struct tsession *ts = malloc(sizeof(struct tsession) + BUFSIZE * 2);
+
+ ts->buf1 = (char *)(&ts[1]);
+ ts->buf2 = ts->buf1 + BUFSIZE;
+
+ ts->sockfd = sockfd;
+
+ ts->rdidx1 = ts->wridx1 = ts->size1 = 0;
+ ts->rdidx2 = ts->wridx2 = ts->size2 = 0;
+
+ /* Got a new connection, set up a tty and spawn a shell. */
+
+ pty = getpty(tty_name);
+
+ if (pty < 0) {
+ syslog_msg(LOG_USER, LOG_ERR, "All network ports in use!");
+ return 0;
+ }
+
+ if (pty > maxfd)
+ maxfd = pty;
+
+ ts->ptyfd = pty;
+
+ /* Make the telnet client understand we will echo characters so it
+ * should not do it locally. We don't tell the client to run linemode,
+ * because we want to handle line editing and tab completion and other
+ * stuff that requires char-by-char support.
+ */
+
+ send_iac(ts, DO, TELOPT_ECHO);
+ send_iac(ts, DO, TELOPT_LFLOW);
+ send_iac(ts, WILL, TELOPT_ECHO);
+ send_iac(ts, WILL, TELOPT_SGA);
+
+
+ if ((pid = fork()) < 0) {
+ syslog_msg(LOG_USER, LOG_ERR, "Can`t forking");
+ }
+ if (pid == 0) {
+ /* In child, open the child's side of the tty. */
+ int i;
+
+ for(i = 0; i <= maxfd; i++)
+ close(i);
+ /* make new process group */
+ setsid();
+
+ if (open(tty_name, O_RDWR /*| O_NOCTTY*/) < 0) {
+ syslog_msg(LOG_USER, LOG_ERR, "Could not open tty");
+ exit(1);
+ }
+ dup(0);
+ dup(0);
+
+ tcsetpgrp(0, getpid());
+
+ /* The pseudo-terminal allocated to the client is configured to operate in
+ * cooked mode, and with XTABS CRMOD enabled (see tty(4)).
+ */
+
+ tcgetattr(0, &termbuf);
+ termbuf.c_lflag |= ECHO; /* if we use readline we dont want this */
+ termbuf.c_oflag |= ONLCR|XTABS;
+ termbuf.c_iflag |= ICRNL;
+ termbuf.c_iflag &= ~IXOFF;
+ /*termbuf.c_lflag &= ~ICANON;*/
+ tcsetattr(0, TCSANOW, &termbuf);
+
+ /* exec shell, with correct argv and env */
+ execv(loginpath, (char *const *)argv_init);
+
+ /* NOT REACHED */
+ syslog_msg(LOG_USER, LOG_ERR, "execv error");
+ exit(1);
+ }
+
+ ts->shell_pid = pid;
+
+ return ts;
+}
+
+static void
+free_session(struct tsession *ts)
+{
+ struct tsession *t = sessions;
+
+ /* Unlink this telnet session from the session list. */
+ if(t == ts)
+ sessions = ts->next;
+ else {
+ while(t->next != ts)
+ t = t->next;
+ t->next = ts->next;
+ }
+
+ kill(ts->shell_pid, SIGKILL);
+
+ wait4(ts->shell_pid, NULL, 0, NULL);
+
+ close(ts->ptyfd);
+ close(ts->sockfd);
+
+ if(ts->ptyfd == maxfd || ts->sockfd == maxfd)
+ maxfd--;
+ if(ts->ptyfd == maxfd || ts->sockfd == maxfd)
+ maxfd--;
+
+ free(ts);
+}
+
+int
+telnetd_main(int argc, char **argv)
+{
+ struct sockaddr_in sa;
+ int master_fd;
+ fd_set rdfdset, wrfdset;
+ int selret;
+ int on = 1;
+ int portnbr = 23;
+ int c;
+
+ /* check if user supplied a port number */
+
+ for (;;) {
+ c = getopt( argc, argv, "p:l:");
+ if (c == EOF) break;
+ switch (c) {
+ case 'p':
+ portnbr = atoi(optarg);
+ break;
+ case 'l':
+ loginpath = strdup (optarg);
+ break;
+ default:
+ show_usage();
+ }
+ }
+
+ if (access(loginpath, X_OK) < 0) {
+ error_msg_and_die ("'%s' unavailable.", loginpath);
+ }
+
+ argv_init[0] = loginpath;
+ sessions = 0;
+
+ /* Grab a TCP socket. */
+
+ master_fd = socket(AF_INET, SOCK_STREAM, 0);
+ if (master_fd < 0) {
+ perror_msg_and_die("socket");
+ }
+ (void)setsockopt(master_fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+
+ /* Set it to listen to specified port. */
+
+ memset((void *)&sa, 0, sizeof(sa));
+ sa.sin_family = AF_INET;
+ sa.sin_port = htons(portnbr);
+
+ if (bind(master_fd, (struct sockaddr *) &sa, sizeof(sa)) < 0) {
+ perror_msg_and_die("bind");
+ }
+
+ if (listen(master_fd, 1) < 0) {
+ perror_msg_and_die("listen");
+ }
+
+ if (daemon(0, 0) < 0)
+ perror_msg_and_die("daemon");
+
+
+ maxfd = master_fd;
+
+ do {
+ struct tsession *ts;
+
+ FD_ZERO(&rdfdset);
+ FD_ZERO(&wrfdset);
+
+ /* select on the master socket, all telnet sockets and their
+ * ptys if there is room in their respective session buffers.
+ */
+
+ FD_SET(master_fd, &rdfdset);
+
+ ts = sessions;
+ while (ts) {
+ /* buf1 is used from socket to pty
+ * buf2 is used from pty to socket
+ */
+ if (ts->size1 > 0) {
+ FD_SET(ts->ptyfd, &wrfdset); /* can write to pty */
+ }
+ if (ts->size1 < BUFSIZE) {
+ FD_SET(ts->sockfd, &rdfdset); /* can read from socket */
+ }
+ if (ts->size2 > 0) {
+ FD_SET(ts->sockfd, &wrfdset); /* can write to socket */
+ }
+ if (ts->size2 < BUFSIZE) {
+ FD_SET(ts->ptyfd, &rdfdset); /* can read from pty */
+ }
+ ts = ts->next;
+ }
+
+ selret = select(maxfd + 1, &rdfdset, &wrfdset, 0, 0);
+
+ if (!selret)
+ break;
+
+ /* First check for and accept new sessions. */
+ if (FD_ISSET(master_fd, &rdfdset)) {
+ int fd, salen;
+
+ salen = sizeof(sa);
+ if ((fd = accept(master_fd, (struct sockaddr *)&sa,
+ &salen)) < 0) {
+ continue;
+ } else {
+ /* Create a new session and link it into
+ our active list. */
+ struct tsession *new_ts = make_new_session(fd);
+ if (new_ts) {
+ new_ts->next = sessions;
+ sessions = new_ts;
+ if (fd > maxfd)
+ maxfd = fd;
+ } else {
+ close(fd);
+ }
+ }
+ }
+
+ /* Then check for data tunneling. */
+
+ ts = sessions;
+ while (ts) { /* For all sessions... */
+ int maxlen, w, r;
+ struct tsession *next = ts->next; /* in case we free ts. */
+
+ if (ts->size1 && FD_ISSET(ts->ptyfd, &wrfdset)) {
+ int num_totty;
+ char *ptr;
+ /* Write to pty from buffer 1. */
+
+ ptr = remove_iacs(ts, &num_totty);
+
+ w = write(ts->ptyfd, ptr, num_totty);
+ if (w < 0) {
+ free_session(ts);
+ ts = next;
+ continue;
+ }
+ ts->wridx1 += w;
+ ts->size1 -= w;
+ if (ts->wridx1 == BUFSIZE)
+ ts->wridx1 = 0;
+ }
+
+ if (ts->size2 && FD_ISSET(ts->sockfd, &wrfdset)) {
+ /* Write to socket from buffer 2. */
+ maxlen = MIN(BUFSIZE - ts->wridx2, ts->size2);
+ w = write(ts->sockfd, ts->buf2 + ts->wridx2, maxlen);
+ if (w < 0) {
+ free_session(ts);
+ ts = next;
+ continue;
+ }
+ ts->wridx2 += w;
+ ts->size2 -= w;
+ if (ts->wridx2 == BUFSIZE)
+ ts->wridx2 = 0;
+ }
+
+ if (ts->size1 < BUFSIZE && FD_ISSET(ts->sockfd, &rdfdset)) {
+ /* Read from socket to buffer 1. */
+ maxlen = MIN(BUFSIZE - ts->rdidx1,
+ BUFSIZE - ts->size1);
+ r = read(ts->sockfd, ts->buf1 + ts->rdidx1, maxlen);
+ if (!r || (r < 0 && errno != EINTR)) {
+ free_session(ts);
+ ts = next;
+ continue;
+ }
+ if(!*(ts->buf1 + ts->rdidx1 + r - 1)) {
+ r--;
+ if(!r)
+ continue;
+ }
+ ts->rdidx1 += r;
+ ts->size1 += r;
+ if (ts->rdidx1 == BUFSIZE)
+ ts->rdidx1 = 0;
+ }
+
+ if (ts->size2 < BUFSIZE && FD_ISSET(ts->ptyfd, &rdfdset)) {
+ /* Read from pty to buffer 2. */
+ maxlen = MIN(BUFSIZE - ts->rdidx2,
+ BUFSIZE - ts->size2);
+ r = read(ts->ptyfd, ts->buf2 + ts->rdidx2, maxlen);
+ if (!r || (r < 0 && errno != EINTR)) {
+ free_session(ts);
+ ts = next;
+ continue;
+ }
+ ts->rdidx2 += r;
+ ts->size2 += r;
+ if (ts->rdidx2 == BUFSIZE)
+ ts->rdidx2 = 0;
+ }
+
+ if (ts->size1 == 0) {
+ ts->rdidx1 = 0;
+ ts->wridx1 = 0;
+ }
+ if (ts->size2 == 0) {
+ ts->rdidx2 = 0;
+ ts->wridx2 = 0;
+ }
+ ts = next;
+ }
+
+ } while (1);
+
+ return 0;
+}