[src/trunk]: src/usr.bin/telnet clarify reverse lookup and -N.

[itojun <itojun%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/5af4b1035d43
branches:  trunk
changeset: 481382:5af4b1035d43
user:      itojun <itojun%NetBSD.org@localhost>
date:      Thu Jan 27 19:20:49 2000 +0000

description:
clarify reverse lookup and -N.
getaddrinfo(AI_CANONNAME) does not imply reverse lookup.

diffstat:

 usr.bin/telnet/commands.c |  57 ++++++++++++++++++++++++----------------------
 1 files changed, 30 insertions(+), 27 deletions(-)

diffs (108 lines):

diff -r 96aaf20abd54 -r 5af4b1035d43 usr.bin/telnet/commands.c
--- a/usr.bin/telnet/commands.c Thu Jan 27 17:39:20 2000 +0000
+++ b/usr.bin/telnet/commands.c Thu Jan 27 19:20:49 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: commands.c,v 1.35 1999/12/13 04:52:20 itojun Exp $     */
+/*     $NetBSD: commands.c,v 1.36 2000/01/27 19:20:49 itojun Exp $     */
 
 /*
  * Copyright (C) 1997 and 1998 WIDE Project.
@@ -67,7 +67,7 @@
 #if 0
 static char sccsid[] = "@(#)commands.c 8.4 (Berkeley) 5/30/95";
 #else
-__RCSID("$NetBSD: commands.c,v 1.35 1999/12/13 04:52:20 itojun Exp $");
+__RCSID("$NetBSD: commands.c,v 1.36 2000/01/27 19:20:49 itojun Exp $");
 #endif
 #endif /* not lint */
 
@@ -2138,7 +2138,7 @@
        }
     }
     if (In3270 && transcom) {
-       printf("Transparent mode command is '%s'.\n", transcom);
+       printf("Transparent mode command is '%s'.\n", transcom);
     }
 #   endif /* defined(unix) */
     (void) fflush(stdout);
@@ -2263,45 +2263,49 @@
        hostname = hostp;
 
     if (!portp) {
-      telnetport = 1;
-      portp = "telnet";
+       telnetport = 1;
+       portp = "telnet";
     } else if (portp[0] == '-') {
-      /* use telnet negotiation if port number/name preceded by minus sign */
-      telnetport = 1;
-      portp++;
+       /* use telnet negotiation if port number/name preceded by minus sign */
+       telnetport = 1;
+       portp++;
     }
 
     memset(&hints, 0, sizeof(hints));
-    hints.ai_flags = AI_NUMERICHOST;
     hints.ai_family = AF_UNSPEC;
     hints.ai_socktype = SOCK_STREAM;
     hints.ai_protocol = 0;
+    hints.ai_flags = AI_NUMERICHOST;   /* avoid forward lookup */
     error = getaddrinfo(hostname, portp, &hints, &res0);
     if (!error) {
-       /*numeric*/
-       freeaddrinfo(res0);
-       memset(&hints, 0, sizeof(hints));
-       hints.ai_flags = doaddrlookup ? AI_CANONNAME : 0; /*reverse lookup*/
-       hints.ai_flags |= AI_NUMERICHOST;
-       hints.ai_family = AF_UNSPEC;
-       hints.ai_socktype = SOCK_STREAM;
-       hints.ai_protocol = 0;
-       error = getaddrinfo(hostname, portp, &hints, &res0);
+       /* numeric */
+       if (doaddrlookup &&
+           getnameinfo(res0->ai_addr, res0->ai_addrlen,
+               _hostname, sizeof(_hostname), NULL, 0, NI_NAMEREQD) == 0)
+           ; /* okay */
+       else {
+           strncpy(_hostname, hostname, sizeof(_hostname) - 1);
+           _hostname[sizeof(_hostname) - 1] = '\0';
+       }
     } else {
-       /*non-numeric*/
+       /* FQDN - try again with forward DNS lookup */
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_protocol = 0;
+       hints.ai_flags = AI_CANONNAME;
        error = getaddrinfo(hostname, portp, &hints, &res0);
+       if (error) {
+           fprintf(stderr, "%s: %s\n", hostname, gai_strerror(error));
+           return 0;
+       }
+       if (res0->ai_canonname) {
+           (void) strncpy(_hostname, res0->ai_canonname,
+               sizeof(_hostname) - 1);
+       } else
+           (void) strncpy(_hostname, hostname, sizeof(_hostname) - 1);
+       _hostname[sizeof(_hostname) - 1] = '\0';
     }
-    if (error) {
-      fprintf(stderr, "%s: %s\n", hostname, gai_strerror(error));
-      return 0;
-    }
-
-    if (res0->ai_canonname)
-       (void) strcpy(_hostname, res0->ai_canonname);
     hostname = _hostname;
 
     net = -1;
@@ -2878,7 +2882,6 @@
                        return -1;
                }
                if (ai->ai_family != res->ai_family) {
-                       fprintf(stderr, "%s: address family mismach\n", cp);
                        freeaddrinfo(res);
                        return -1;
                }