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/*
* lbcd load module to check an arbitrary TCP service.
*
* Written by Larry Schwimmer
* Copyright 1998, 2008, 2012
* The Board of Trustees of the Leland Stanford Junior University
*
* See LICENSE for licensing terms.
*/
#include <config.h>
#include <portable/socket.h>
#include <portable/system.h>
#include <ctype.h>
#include <server/internal.h>
#include <modules/modules.h>
#include <util/macros.h>
/*
* Generic TCP service probe. Takes the host, the service name, the port,
* an optional string to look for in the reply, and a timeout. Returns 0 on
* success and -1 on failure.
*/
int
probe_tcp(const char *host, const char *service, short port,
const char *replycheck, int timeout)
{
socket_type sd;
int retval = 0;
sd = tcp_connect(host ? host : "localhost", service, port);
if (sd == INVALID_SOCKET)
return -1;
else {
if (replycheck) {
retval = lbcd_check_reply(sd, timeout, replycheck);
/* Only for clean shutdown, don't care about failure. */
if (socket_write(sd, "quit\r\n", 6) < 0) {}
}
socket_close(sd);
}
return retval;
}
/*
* The module interface with the rest of lbcd. Unlike many of the module
* interfaces, this requires the port argument to determine which TCP port to
* probe. Always probes localhost. Returns the weight or -1 on error.
*/
int
lbcd_tcp_weight(uint32_t *weight_val, uint32_t *incr_val UNUSED,
int timeout, const char *portarg, struct lbcd_reply *lb UNUSED)
{
const char *service = NULL;
short port = 0;
const char *cp;
/*
* Parse portarg. If it's all digits, treat it as a port number;
* otherwise, treat it as a service.
*/
if (portarg == NULL)
return -1;
for (cp = portarg; *cp != '\0'; cp++) {
if (!isdigit((int) *cp)) {
service = portarg;
break;
}
}
if (*cp == '\0') {
port = (short) atoi(portarg);
if (port < 1)
return -1;
}
/* Connect to the port, set weight, and return */
*weight_val = (uint32_t) probe_tcp("localhost", service, port, NULL,
timeout);
return *weight_val;
}
/*
* Test routine.
*/
#ifdef MAIN
int
main(int argc, char *argv[])
{
int status;
uint32_t i;
status = probe_tcp(argv[1], "smtp", 25, "220", 5);
printf("%s service %savailable\n", "smtp", status ? "not " : "");
if (lbcd_tcp_weight(&i, &i, 5, "smtp") == 0)
printf("service available\n");
else
printf("service not available\n");
return status;
}
#endif
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