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TMXR: Add support for tcp port listen backlog

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The system default of no extra backlog has generally worked well for
simulated mux devices for a long time since reasonable arrival of
new tcp connections is usually expected to have gaps of minutes.

If, for some reason, connection arrivals in a particular case can
happen multiple times per second, a backlog might be useful.
This commit is contained in:
Mark Pizzolato 2023-06-30 03:35:54 -10:00
parent f9a4b8c6b9
commit 49902b830e
2 changed files with 55 additions and 11 deletions
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63
sim_tmxr.c
View File

@ -79,6 +79,7 @@
tmxr_clear_modem_control_passthru - disable modem control on a multiplexer
tmxr_set_port_speed_control - Declare that tmxr_set_config_line is used
tmxr_clear_port_speed_control - Declare that tmxr_set_config_line is not used
tmxr_set_backlog - set listen backlog
tmxr_set_line_port_speed_control - Declare that tmxr_set_config_line is used for line
tmxr_clear_line_port_speed_control - Declare that tmxr_set_config_line is not used for line
tmxr_set_get_modem_bits - set and/or get a line modem bits
@ -243,15 +244,15 @@
The command syntax for a single line device (MX) is:
sim> attach MX port{;notelnet}|{;nomessage}
sim> attach MX port{;backlog=n}{;notelnet}|{;nomessage}
sim> attach MX Connect=serN{;config}
sim> attach MX Connect=COM9{;config}
sim> attach MX Connect=host:port{;notelnet}|{;nomessage}
The command syntax for ANY multi-line device is:
sim> attach MX port{;notelnet}|{;nomessage} ; Defines the master listening port for the mux and optionally allows non-telnet (i.e. raw socket) operation for all lines.
sim> attach MX Line=n,port{;notelnet}|{;nomessage} ; Defines a line specific listen port for a particular line. Each line can have a separate listen port and the mux can have its own as well. Optionally disable telnet wire protocol (i.e. raw socket)
sim> attach MX port{;backlog=n}{;notelnet}|{;nomessage} ; Defines the master listening port for the mux and optionally allows non-telnet (i.e. raw socket) operation for all lines.
sim> attach MX Line=n,port{;backlog=n}{;notelnet}|{;nomessage} ; Defines a line specific listen port for a particular line. Each line can have a separate listen port and the mux can have its own as well. Optionally disable telnet wire protocol (i.e. raw socket)
sim> attach MX Line=n,Connect=serN{;config} ; Connects line n to simh generic serial port N (port list visible with the sim> SHOW SERIAL command), the optional ";config" data specifies the speed, parity and stop bits for the connection
; DTR (and RTS) will be raised at attach time and will drop at detach/disconnect time
sim> attach MX Line=n,Connect=host:port{;notelnet} ; Causes a connection to be established to the designated host:port. The actual connection will happen in a non-blocking fashion and will be completed and/or re-established by the normal tmxr_poll_conn activities
@ -915,7 +916,11 @@ if (tptr == NULL) /* no more mem? */
return tptr;
if (mp->port) { /* copy port */
sprintf (growstring(&tptr, 33 + strlen (mp->port)), "%s%s", mp->port,
char backlog[32] = "";
if (mp->backlog != 0)
snprintf (backlog, sizeof (backlog), ";backlog=%u", mp->backlog);
sprintf (growstring(&tptr, 33 + strlen (mp->port)), "%s%s%s", mp->port, backlog,
mp->notelnet ? ";notelnet" :
(mp->nomessage ? ";nomessage" :
""));
@ -998,7 +1003,11 @@ if (lp->destination || lp->port || lp->txlogname || (lp->conn == TMXR_LINE_DISAB
if (lp->mp->packet != lp->packet)
sprintf (growstring(&tptr, 8), ",Packet");
if (lp->port) {
sprintf (growstring(&tptr, 32 + strlen (lp->port)), ",%s%s%s", lp->port,
char backlog[32] = "";
if (lp->backlog != 0)
snprintf (backlog, sizeof (backlog), ";backlog=%u", lp->backlog);
sprintf (growstring(&tptr, 64 + strlen (lp->port)), ",%s%s%s%s", lp->port, backlog,
((lp->mp->notelnet != lp->notelnet) && (!lp->datagram)) ? (lp->notelnet ? ";notelnet" : ";telnet") : "",
((lp->mp->nomessage != lp->nomessage) && (!lp->datagram)) ? (lp->nomessage ? ";nomessage" : ";message") : "");
if (lp->acl) { /* copy acl in pieces */
@ -1216,6 +1225,8 @@ if (mp->master) {
lp = mp->ldsc + i; /* get line desc */
lp->conn = TRUE; /* record connection */
lp->sock = newsock; /* save socket */
free (address);
sim_getnames_sock (lp->sock, NULL, &address);
lp->ipad = address; /* ip address */
tmxr_init_line (lp); /* init line */
lp->notelnet = mp->notelnet; /* apply mux default telnet setting */
@ -1712,6 +1723,16 @@ sim_debug (TMXR_DBG_CFG, mp->dptr, "Speed Mode: Disabled\n");
return SCPE_OK;
}
/* Specify a non-default listen backlog.
The default listen backlog is 0. This API overrides that default.
*/
t_stat tmxr_set_backlog (TMXR *mp, int32 backlog)
{
mp->backlog = backlog;
return SCPE_OK;
}
/* Declare that tmxr_set_config_line is used for line.
This would best be called in a device reset routine and left set.
@ -2899,6 +2920,7 @@ SOCKET sock;
SERHANDLE serport;
CONST char *tptr = cptr;
t_bool nolog, notelnet, listennotelnet, nomessage, listennomessage, modem_control, loopback, datagram, packet, disabled;
int32 listenbacklog;
TMLN *lp;
t_stat r = SCPE_OK;
@ -2914,6 +2936,7 @@ for (i = 0; i < mp->lines; i++) { /* initialize lines */
}
notelnet = listennotelnet = mp->notelnet;
nomessage = listennomessage = mp->nomessage;
listenbacklog = mp->backlog;
mp->ring_sock = INVALID_SOCKET;
free (mp->ring_ipad);
mp->ring_ipad = NULL;
@ -3099,7 +3122,7 @@ while (*tptr) {
cptr = init_cptr;
}
cptr = get_glyph_nc (cptr, port, ';');
sock = sim_master_sock (port, &r); /* make master socket to validate port */
sock = sim_master_sock (port, &r); /* make master socket to validate port */
if (r)
return sim_messagef (SCPE_ARG, "Invalid Port Specifier: %s\n", port);
if (sock == INVALID_SOCKET) /* open error */
@ -3140,7 +3163,13 @@ while (*tptr) {
strlcat (acl, option + 7, sizeof (acl));
}
else
return sim_messagef (SCPE_ARG, "Invalid Specifier: %s\n", option);
if (0 == memcmp (option, "BACKLOG=", 8)) {
listenbacklog = (int32) get_uint (option + 8, 10, SOMAXCONN, &r);
if (r)
return sim_messagef (SCPE_ARG, "Invalid Listen Backlog: %s\n", option + 8);
}
else
return sim_messagef (SCPE_ARG, "Invalid Specifier: %s\n", option);
cptr = get_glyph (cptr, option, ';');
}
}
@ -3298,7 +3327,11 @@ while (*tptr) {
if (lp->framer)
continue; /* skip framer lines */
if ((listen[0]) && (!datagram)) {
sock = sim_master_sock (listen, &r); /* make master socket */
sock = sim_master_sock_ex (listen, &r, /* make master socket */
((sim_switches & SWMASK ('U')) ? SIM_SOCK_OPT_REUSEADDR : 0) |
(mp->packet ? SIM_SOCK_OPT_NODELAY : 0) |
SIM_SOCK_OPT_SET_BACKLOG(listenbacklog));
if (r)
return sim_messagef (SCPE_ARG, "Invalid network listen port: %s\n", listen);
if (sock == INVALID_SOCKET) /* open error */
@ -3319,6 +3352,7 @@ while (*tptr) {
mp->ring_start_time = 0;
mp->notelnet = listennotelnet; /* save desired telnet behavior flag */
mp->nomessage = listennomessage; /* save desired telnet behavior flag */
mp->backlog = listenbacklog; /* save desired listening port backlog */
if (acl[0])
mp->acl = strdup (acl); /* save specified access control list */
for (i = 0; i < mp->lines; i++) { /* initialize lines */
@ -3517,7 +3551,14 @@ while (*tptr) {
if ((listen[0]) && (!datagram)) {
if ((mp->lines == 1) && (mp->master))
return sim_messagef (SCPE_ARG, "Single Line MUX can have either line specific OR MUX listener but NOT both\n");
sock = sim_master_sock (listen, &r); /* make master socket */
if (listenbacklog != mp->backlog)
lp->backlog = listenbacklog;
else
lp->backlog = mp->backlog;
sock = sim_master_sock_ex (listen, &r, /* make master socket */
((sim_switches & SWMASK ('U')) ? SIM_SOCK_OPT_REUSEADDR : 0) |
(lp->packet ? SIM_SOCK_OPT_NODELAY : 0) |
SIM_SOCK_OPT_SET_BACKLOG(lp->backlog));
if (r)
return sim_messagef (SCPE_ARG, "Invalid Listen Specification: %s\n", listen);
if (sock == INVALID_SOCKET) /* open error */
@ -4326,7 +4367,7 @@ if (single_line) { /* Single Line Multiplexer */
fprintf (st, "passing port configuration information and modem signals.\n");
}
fprintf (st, "A Telnet listening port can be configured with:\n\n");
fprintf (st, " sim> ATTACH %s {interface:}port\n\n", dptr->name);
fprintf (st, " sim> ATTACH %s {interface:}port{;backlog=n}\n\n", dptr->name);
fprintf (st, "Connections to the specified port, by default, will be unrestricted.\n");
fprintf (st, "Connections from particular IPv4 or IPv6 addresses can be restricted\n");
fprintf (st, "or allowed based on rules you can add to the \"{interface:}port\"\n");
@ -4502,7 +4543,7 @@ else {
fprintf (st, " sim> ATTACH -V %s Line=n,Connect=SerN\n\n", dptr->name);
fprintf (st, "Line specific tcp listening ports are supported. These are configured\n");
fprintf (st, "using commands of the form:\n\n");
fprintf (st, " sim> ATTACH %s Line=n,{interface:}port{;notelnet}|{;nomessage}\n\n", dptr->name);
fprintf (st, " sim> ATTACH %s Line=n,{interface:}port{;notelnet}{;nomessage}{;backlog=n}\n\n", dptr->name);
fprintf (st, "Connections to the specified port, by default, will be unrestricted.\n");
fprintf (st, "Connections from particular IPv4 or IPv6 addresses can be restricted\n");
fprintf (st, "or allowed based on rules you can add to the \"{interface:}port\"\n");

3
sim_tmxr.h
View File

@ -136,6 +136,7 @@ struct tmln {
SOCKET master; /* line specific master socket */
char *port; /* line specific listening port */
char *acl; /* Access control list (CIDR) to accept or reject connects from */
uint32 backlog; /* line specific listening backlog */
int32 acl_accepted_sessions; /* count of ACL accepted tcp connections */
int32 acl_rejected_sessions; /* count of ACL rejected tcp connections */
int32 sessions; /* count of tcp connections received */
@ -218,6 +219,7 @@ struct tmxr {
char *acl; /* Access control list (CIDR) to accept or reject connects from */
int32 acl_accepted_sessions; /* count of ACL accepted tcp connections */
int32 acl_rejected_sessions; /* count of ACL rejected tcp connections */
uint32 backlog; /* listen backlog */
UNIT *uptr; /* polling unit (connection) */
char logfiletmpl[FILENAME_MAX]; /* template logfile name */
int32 txcount; /* count of transmit bytes */
@ -265,6 +267,7 @@ t_stat tmxr_set_nomessage (TMXR *mp);
t_stat tmxr_clear_nomessage (TMXR *mp);
t_stat tmxr_set_port_speed_control (TMXR *mp);
t_stat tmxr_clear_port_speed_control (TMXR *mp);
t_stat tmxr_set_backlog (TMXR *mp, int32 backlog);
t_stat tmxr_set_line_port_speed_control (TMXR *mp, int line);
t_stat tmxr_clear_line_port_speed_control (TMXR *mp, int line);
t_stat tmxr_set_get_modem_bits (TMLN *lp, int32 bits_to_set, int32 bits_to_clear, int32 *incoming_bits);