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/*
* lbcd load module to check HTTP server.
*
* Written by Larry Schwimmer
* Copyright 1997, 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>
#ifdef HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif
#include <sys/time.h>
#include <server/internal.h>
#include <modules/modules.h>
#include <util/macros.h>
/* The most basic HTTP query that we can perform. */
#define QUERY "GET / HTTP/1.0\r\n\r\n"
/*
* Probe an HTTP server. Takes the hostname, the timeout, and an optional
* port as a string which is taken to be a port number. If host is NULL,
* localhost is used. If the port is not given, probes port 80. Returns
* success (0) if and only if the HTTP server returns a status code of 200, so
* cannot be used with a server that returns a redirect for /. Returns -1 on
* failure.
*/
static int
probe_http(const char *host, int timeout, const char *portarg)
{
socket_type sd;
int retval = 0;
short port = 80;
const char *service = "http";
if (portarg != NULL) {
port = (short) atoi(portarg);
if (port < 1)
port = 80;
else
service = NULL; /* Force use of supplied port number. */
}
sd = tcp_connect(host ? host : "localhost", service, port);
if (sd == INVALID_SOCKET)
return -1;
else {
struct timeval tv = { 0, 0 };
fd_set rset;
char buf[17];
char *p;
tv.tv_sec = timeout;
if (socket_write(sd, QUERY, sizeof(QUERY)) < (ssize_t) sizeof(QUERY)) {
socket_close(sd);
return -1;
}
FD_ZERO(&rset);
FD_SET(sd, &rset);
retval = -1;
if (select(sd + 1, &rset, NULL, NULL, &tv) > 0) {
buf[sizeof(buf) - 1] = '\0';
/* Look for a response starting with 20x or 30x. */
if (socket_read(sd, buf, sizeof(buf) - 1) > 0) {
p = strstr(buf, "20");
if (p == NULL)
p = strstr(buf, "30");
if (p != NULL && isdigit((int) p[2]))
retval = 0;
}
}
socket_close(sd);
}
return retval;
}
/*
* The module interface with the rest of lbcd. Only supports probing
* localhost.
*/
int
lbcd_http_weight(uint32_t *weight_val, uint32_t *incr_val UNUSED,
int timeout, const char *portarg,
struct lbcd_reply *lb UNUSED)
{
return *weight_val = probe_http("localhost", timeout, portarg);
}
/*
* Test routine.
*/
#ifdef MAIN
int
main(int argc, char *argv[])
{
int status;
status = probe_http(argv[1], 5, NULL);
printf("http service %savailable\n", status ? "not " : "");
return status;
}
#endif
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