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/* $Id: proxylogger.c,v 1.4 2004/05/27 21:27:37 mjt Exp $
* A trivial program (should be invoked by inetd) that
* writes out a string "550 ESMTP_unwelcome [peer.ip.add.ress]"
* to the network and optionally waits for a string in form
* [junk]protocol:ip.add.re.ss:port\n
* from the remote system. May be used as a destination for
* proxycheck program. All connections (together with the
* information in the above form, if given) are optionally
* logged to a specified file.
* Options:
* -n - do not wait for a proxy connection info
* -t timeout - timeout in secs
* -l logfile - where to log proxy/connection info
* -s say - what to say
* -S saylast - what to say when correct proxy parameters are seen
*/
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifndef INADDR_NONE
# define INADDR_NONE ((in_addr_t)-1)
#endif
struct sockaddr_in peer;
struct in_addr pxyaddr;
unsigned short pxyport;
char *logfile;
char *say = "550 open proxy cheking service";
char *saylast = "550 ESMTP_unwelcome";
char buf[2048];
static struct proto {
const char *see;
int len;
const char *say;
} protos[] = {
{ "hc", 2, "hc" },
{ "http", 4, "hc" },
{ "http-connect", 12, "hc" },
/* { "hg", 2, "hg" },
{ "http-get", 8, "hg" },*/
{ "ho", 2, "ho" },
{ "http-post", 9, "ho" },
{ "hu", 2, "hu" },
{ "http-put", 8, "hu" },
{ "wg", 2, "wg" },
{ "wingate", 7, "wg" },
{ "s4", 2, "s4" },
{ "socks4", 6, "s4" },
{ "s5", 2, "s5" },
{ "socks5", 6, "s5" },
{ "fu", 2, "fu" },
{ "ftp", 3, "fu" },
{ NULL, 0, NULL }
};
void info(const char *proto) {
int logfd;
if (logfile && (logfd = open(logfile, O_CREAT|O_WRONLY|O_APPEND, 0644)) > 0) {
time_t t = time(NULL);
struct tm *tm = localtime(&t);
int l = sprintf(buf, "%04d-%02d-%02d %02d:%02d:%02d %s",
tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec,
inet_ntoa(peer.sin_addr));
if (proto)
l += sprintf(buf + l, " %s:%s:%d", proto, inet_ntoa(pxyaddr), pxyport);
buf[l++] = '\n';
write(logfd, buf, l);
close(logfd);
}
if (proto) {
int l = sprintf(buf, "%s [%s]\r\n", saylast, inet_ntoa(peer.sin_addr));
write(1, buf, l);
}
exit(0);
}
void timedout(int sig) {
sig = sig;
info(NULL);
}
void findproxyinfo(char *b, char *be) {
const struct proto *pr;
char *p;
*be = '\0';
while(b < be) {
for(pr = protos; pr->see; ++pr)
if (*b == pr->see[0] &&
b + pr->len < be &&
b[pr->len] == ':' &&
memcmp(pr->see, b, pr->len) == 0)
break;
if (!pr->see) {
++b;
continue;
}
b += pr->len + 1;
if ((p = strchr(b, ':')) == NULL) continue;
*p = '\0';
pxyaddr.s_addr = inet_addr(b);
*p++ = ':';
if (pxyaddr.s_addr == INADDR_NONE) continue;
b = p;
pxyport = 0;
while(*b >= '0' && *b <= '9' && b - p < 6)
pxyport = pxyport * 10 + (*b++ - '0');
if (!(*b >= 'a' && *b <= 'z') && !(*b >= 'A' && *b <= 'Z')
&& !(*b >= '0' && *b <= '9'))
info(pr->say);
}
}
int main(int argc, char **argv) {
int timeout = 30;
int nowait = 0;
int l, r, wl;
char *w;
while((l = getopt(argc, argv, "t:l:s:S:n")) != EOF)
switch(l) {
case 't': timeout = atoi(optarg); break;
case 'l': logfile = optarg; break;
case 's': say = optarg; break;
case 'S': saylast = optarg; break;
case 'n': nowait = 1; break;
default: return 1;
}
l = sizeof(peer);
if (getpeername(0, (struct sockaddr*)&peer, &l) < 0 ||
l != sizeof(peer) || peer.sin_family != AF_INET)
return 1;
signal(SIGALRM, timedout);
signal(SIGPIPE, SIG_IGN);
alarm(timeout);
/* print some easily recognizeable string */
wl = sprintf(buf, "%s [%s]\r\n", say, inet_ntoa(peer.sin_addr));
w = (char*)malloc(wl);
memcpy(w, buf, wl);
write(0, w, wl);
if (nowait || !logfile)
info(NULL);
/* read data from the network.
* try to recognize:
* junk space proto:ipaddr:port space
*/
l = 0;
while((r = read(0, buf + l, sizeof(buf) - l - 1)) > 0) {
char *e;
char *s = buf + l - 30;
if (s < buf) s = buf;
r += l;
e = buf + r;
findproxyinfo(s, e);
for(s = buf + l; s < e; ++s)
if (*s == '\n')
if (write(1, w, wl) < 0)
info(NULL);
}
info(NULL);
return 0;
}
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