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fix_options.c revision 1.2 
      1  /*
      2   * Routine to disable IP-level socket options. This code was taken from 4.4BSD
      3   * rlogind source, but all mistakes in it are my fault.
      4   *
      5   * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
      6   */
      7 
      8 #ifndef lint
      9 static char sccsid[] = "@(#) fix_options.c 1.3 94/12/28 17:42:22";
     10 #endif
     11 
     12 #include <sys/types.h>
     13 #include <sys/param.h>
     14 #include <netinet/in.h>
     15 #include <netdb.h>
     16 #include <stdio.h>
     17 #include <syslog.h>
     18 
     19 #include "tcpd.h"
     20 
     21 /* fix_options - get rid of IP-level socket options */
     22 
     23 fix_options(request)
     24 struct request_info *request;
     25 {
     26 #ifdef IP_OPTIONS
     27     unsigned char optbuf[BUFSIZ / 3], *cp;
     28     char    lbuf[BUFSIZ], *lp;
     29     int     optsize = sizeof(optbuf), ipproto;
     30     struct protoent *ip;
     31     int     fd = request->fd;
     32     int     len = sizeof lbuf;
     33 
     34     if ((ip = getprotobyname("ip")) != 0)
     35 	ipproto = ip->p_proto;
     36     else
     37 	ipproto = IPPROTO_IP;
     38 
     39     if (getsockopt(fd, ipproto, IP_OPTIONS, (char *) optbuf, &optsize) == 0
     40 	&& optsize != 0) {
     41 	lp = lbuf;
     42 	for (cp = optbuf; optsize > 0; cp++, optsize--, lp += 3)
     43 	    len -= snprintf(lp, len, " %2.2x", *cp);
     44 	syslog(LOG_NOTICE,
     45 	       "connect from %s with IP options (ignored):%s",
     46 	       eval_client(request), lbuf);
     47 	if (setsockopt(fd, ipproto, IP_OPTIONS, (char *) 0, optsize) != 0) {
     48 	    syslog(LOG_ERR, "setsockopt IP_OPTIONS NULL: %m");
     49 	    clean_exit(request);
     50 	}
     51     }
     52 #endif
     53 }
     54