Added randomization to the checking for success of outgoing connections and the arrival of incoming connections
This commit is contained in:
Mark Pizzolato
parent
7edcf5f36e
commit
e8e751c2fd
1 changed files with 96 additions and 82 deletions
178
sim_tmxr.c
178
sim_tmxr.c
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@ -807,6 +807,7 @@ if (mp->last_poll_time == 0) { /* first poll initializa
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if ((poll_time - mp->last_poll_time) < TMXR_CONNECT_POLL_INTERVAL)
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return -1; /* too soon to try */
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srand((unsigned int)poll_time);
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tmxr_debug_trace (mp, "tmxr_poll_conn()");
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mp->last_poll_time = poll_time;
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@ -862,95 +863,108 @@ if (mp->master) {
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/* Look for per line listeners or outbound connecting sockets */
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for (i = 0; i < mp->lines; i++) { /* check each line in sequence */
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int j, r = rand();
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lp = mp->ldsc + i; /* get pointer to line descriptor */
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if (lp->connecting) { /* connecting? */
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char *sockname, *peername;
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/* If two simulators are configured with symmetric virtual null modem
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cables pointing at each other, there may be a problem establishing
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a connection if both systems happen to be checking for the success
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of their connections in the exact same order. They can each observe
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success in their respective outgoing connections, which haven't
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actually been 'accept'ed on the peer end of the connection.
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We address this issue by checking for the success of an outgoing
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connection and the arrival of an incoming one in a random order.
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*/
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for (j=0; j<2; j++)
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switch ((j+r)&1) {
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case 0:
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if (lp->connecting) { /* connecting? */
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char *sockname, *peername;
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switch (sim_check_conn(lp->connecting, FALSE))
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{
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case 1: /* successful connection */
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lp->conn = TRUE; /* record connection */
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lp->sock = lp->connecting; /* it now looks normal */
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lp->connecting = 0;
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lp->ipad = realloc (lp->ipad, 1+strlen (lp->destination));
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strcpy (lp->ipad, lp->destination);
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lp->cnms = sim_os_msec ();
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sim_getnames_sock (lp->sock, &sockname, &peername);
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sprintf (msg, "tmxr_poll_conn() - Outgoing Line Connection to %s (%s->%s) established", lp->destination, sockname, peername);
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tmxr_debug_connect_line (lp, msg);
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free (sockname);
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free (peername);
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break;
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case -1: /* failed connection */
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sprintf (msg, "tmxr_poll_conn() - Outgoing Line Connection to %s failed", lp->destination);
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tmxr_debug_connect_line (lp, msg);
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tmxr_reset_ln (lp); /* retry */
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break;
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}
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}
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/* Check for a pending Telnet/tcp connection */
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if (lp->master) {
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while (INVALID_SOCKET != (newsock = sim_accept_conn (lp->master, &address))) {/* got a live one? */
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char *sockname, *peername;
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sim_getnames_sock (newsock, &sockname, &peername);
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sprintf (msg, "tmxr_poll_conn() - Incoming Line Connection from %s (%s->%s)", address, peername, sockname);
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tmxr_debug_connect_line (lp, msg);
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free (sockname);
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free (peername);
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++mp->sessions; /* count the new session */
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if (lp->destination) { /* Virtual Null Modem Cable? */
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char host[CBUFSIZE];
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if (sim_parse_addr (lp->destination, host, sizeof(host), NULL, NULL, 0, NULL, address)) {
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tmxr_msg (newsock, "Rejecting connection from unexpected source\r\n");
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sprintf (msg, "tmxr_poll_conn() - Rejecting line connection from: %s, Expected: %s", address, host);
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tmxr_debug_connect_line (lp, msg);
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sim_close_sock (newsock, 0);
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free (address);
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continue; /* Try for another connection */
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}
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if (lp->connecting) {
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sprintf (msg, "tmxr_poll_conn() - aborting outgoing line connection attempt to: %s", lp->destination);
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tmxr_debug_connect_line (lp, msg);
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sim_close_sock (lp->connecting, 0); /* abort our as yet unconnnected socket */
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lp->connecting = 0;
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}
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}
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if (lp->conn == FALSE) { /* is the line available? */
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if ((!lp->modem_control) || (lp->modembits & TMXR_MDM_DTR)) {
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tmxr_init_line (lp); /* init line */
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lp->conn = TRUE; /* record connection */
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lp->sock = newsock; /* save socket */
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lp->ipad = address; /* ip address */
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if (!lp->notelnet) {
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sim_write_sock (newsock, (char *)mantra, sizeof(mantra));
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tmxr_debug (TMXR_DBG_XMT, lp, "Sending", (char *)mantra, sizeof(mantra));
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switch (sim_check_conn(lp->connecting, FALSE))
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{
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case 1: /* successful connection */
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lp->conn = TRUE; /* record connection */
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lp->sock = lp->connecting; /* it now looks normal */
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lp->connecting = 0;
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lp->ipad = realloc (lp->ipad, 1+strlen (lp->destination));
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strcpy (lp->ipad, lp->destination);
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lp->cnms = sim_os_msec ();
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sim_getnames_sock (lp->sock, &sockname, &peername);
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sprintf (msg, "tmxr_poll_conn() - Outgoing Line Connection to %s (%s->%s) established", lp->destination, sockname, peername);
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tmxr_debug_connect_line (lp, msg);
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free (sockname);
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free (peername);
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break;
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case -1: /* failed connection */
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sprintf (msg, "tmxr_poll_conn() - Outgoing Line Connection to %s failed", lp->destination);
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tmxr_debug_connect_line (lp, msg);
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tmxr_reset_ln (lp); /* retry */
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break;
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}
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tmxr_report_connection (mp, lp);
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lp->cnms = sim_os_msec (); /* time of connection */
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return i;
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}
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else {
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tmxr_msg (newsock, "Line connection not available\r\n");
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tmxr_debug_connect_line (lp, "tmxr_poll_conn() - Line connection not available");
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sim_close_sock (newsock, 0);
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free (address);
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break;
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case 1:
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if (lp->master) { /* Check for a pending Telnet/tcp connection */
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while (INVALID_SOCKET != (newsock = sim_accept_conn (lp->master, &address))) {/* got a live one? */
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char *sockname, *peername;
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sim_getnames_sock (newsock, &sockname, &peername);
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sprintf (msg, "tmxr_poll_conn() - Incoming Line Connection from %s (%s->%s)", address, peername, sockname);
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tmxr_debug_connect_line (lp, msg);
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free (sockname);
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free (peername);
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++mp->sessions; /* count the new session */
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if (lp->destination) { /* Virtual Null Modem Cable? */
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char host[CBUFSIZE];
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if (sim_parse_addr (lp->destination, host, sizeof(host), NULL, NULL, 0, NULL, address)) {
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tmxr_msg (newsock, "Rejecting connection from unexpected source\r\n");
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sprintf (msg, "tmxr_poll_conn() - Rejecting line connection from: %s, Expected: %s", address, host);
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tmxr_debug_connect_line (lp, msg);
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sim_close_sock (newsock, 0);
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free (address);
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continue; /* Try for another connection */
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}
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if (lp->connecting) {
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sprintf (msg, "tmxr_poll_conn() - aborting outgoing line connection attempt to: %s", lp->destination);
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tmxr_debug_connect_line (lp, msg);
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sim_close_sock (lp->connecting, 0); /* abort our as yet unconnnected socket */
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lp->connecting = 0;
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}
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}
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if (lp->conn == FALSE) { /* is the line available? */
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if ((!lp->modem_control) || (lp->modembits & TMXR_MDM_DTR)) {
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tmxr_init_line (lp); /* init line */
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lp->conn = TRUE; /* record connection */
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lp->sock = newsock; /* save socket */
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lp->ipad = address; /* ip address */
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if (!lp->notelnet) {
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sim_write_sock (newsock, (char *)mantra, sizeof(mantra));
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tmxr_debug (TMXR_DBG_XMT, lp, "Sending", (char *)mantra, sizeof(mantra));
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}
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tmxr_report_connection (mp, lp);
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lp->cnms = sim_os_msec (); /* time of connection */
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return i;
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}
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else {
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tmxr_msg (newsock, "Line connection not available\r\n");
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tmxr_debug_connect_line (lp, "tmxr_poll_conn() - Line connection not available");
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sim_close_sock (newsock, 0);
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free (address);
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}
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}
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else {
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tmxr_msg (newsock, "Line connection busy\r\n");
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tmxr_debug_connect_line (lp, "tmxr_poll_conn() - Line connection busy");
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sim_close_sock (newsock, 0);
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free (address);
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}
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}
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}
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}
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else {
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tmxr_msg (newsock, "Line connection busy\r\n");
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tmxr_debug_connect_line (lp, "tmxr_poll_conn() - Line connection busy");
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sim_close_sock (newsock, 0);
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free (address);
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}
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break;
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}
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}
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/* Check for pending serial port connection notification */
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