Add AI_FQDN flag to getaddrinfo(3). Prompted by discussions with djm@

about cert checking in OpenSSH.  Man page wording tweaks thanks to
jmc@.

ok henning@, jmc@; positive feedback from djm@, ajacoutat@

Committing now to reuse guenther@'s libc minor bump instead of
cranking it again, as suggested by deraadt@.

2 files changed, 46 insertions, 22 deletions

diff --git a/src/lib/libc/net/getaddrinfo.3 b/src/lib/libc/net/getaddrinfo.3
index 7250407d65..da6e64683f 100644
--- a/src/lib/libc/net/getaddrinfo.3
+++ b/src/lib/libc/net/getaddrinfo.3
@@ -1,4 +1,4 @@
-.\"     $OpenBSD: getaddrinfo.3,v 1.47 2009/07/09 10:14:41 eric Exp $
+.\"     $OpenBSD: getaddrinfo.3,v 1.48 2011/04/05 00:46:06 matthew Exp $
 .\"     $KAME: getaddrinfo.3,v 1.36 2005/01/05 03:23:05 itojun Exp $
 .\"
 .\" Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
@@ -16,7 +16,7 @@
 .\" OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 .\" PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: July 9 2009 $
+.Dd $Mdocdate: April 5 2011 $
 .Dt GETADDRINFO 3
 .Os
 .Sh NAME
@@ -126,11 +126,33 @@ If the
 bit is set, a successful call to
 .Fn getaddrinfo
 will return a NUL-terminated string containing the canonical name
-of the specified hostname in the
+of the specified host name in the
 .Fa ai_canonname
 element of the first
 .Li addrinfo
 structure returned.
+.It Dv AI_FQDN
+If the
+.Dv AI_FQDN
+bit is set, a successful call to
+.Fn getaddrinfo
+will return a NUL-terminated string containing the fully qualified domain name
+of the specified host name in the
+.Fa ai_canonname
+element of the first
+.Li addrinfo
+structure returned.
+.Pp
+This is different from the
+.Dv AI_CANONNAME
+bit flag that returns the canonical name registered in DNS,
+which may be different from the fully qualified domain name
+that the host name resolved to.
+Only one of the
+.Dv AI_FQDN
+and
+.Dv AI_CANONNAME
+bits can be set.
 .It Dv AI_NUMERICHOST
 If the
 .Dv AI_NUMERICHOST
@@ -438,6 +460,10 @@ function is defined by the
 draft specification and documented in
 .Dv "RFC 3493" ,
 .Dq Basic Socket Interface Extensions for IPv6 .
+.Pp
+The
+.Dv AI_FQDN
+flag bit first appeared in Windows 7.
 .Sh BUGS
 The implementation of
 .Fn getaddrinfo
diff --git a/src/lib/libc/net/getaddrinfo.c b/src/lib/libc/net/getaddrinfo.c
index 7040fa7c37..29cc1f463e 100644
--- a/src/lib/libc/net/getaddrinfo.c
+++ b/src/lib/libc/net/getaddrinfo.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: getaddrinfo.c,v 1.71 2009/11/18 07:43:22 guenther Exp $       */
+/*      $OpenBSD: getaddrinfo.c,v 1.72 2011/04/05 00:46:06 matthew Exp $        */
 /*      $KAME: getaddrinfo.c,v 1.31 2000/08/31 17:36:43 itojun Exp $    */
 
 /*
@@ -309,7 +309,9 @@ getaddrinfo(const char *hostname, const char *servname,
                 if (hints->ai_addrlen || hints->ai_canonname ||
                     hints->ai_addr || hints->ai_next)
                         ERR(EAI_BADHINTS); /* xxx */
-                if (hints->ai_flags & ~AI_MASK)
+                if ((hints->ai_flags & ~AI_MASK) != 0 ||
+                    (hints->ai_flags & (AI_CANONNAME | AI_FQDN)) ==
+                    (AI_CANONNAME | AI_FQDN))
                         ERR(EAI_BADFLAGS);
                 switch (hints->ai_family) {
                 case PF_UNSPEC:
@@ -671,14 +673,13 @@ explore_numeric(const struct addrinfo *pai, const char *hostname,
                     pai->ai_family == PF_UNSPEC /*?*/) {
                         GET_AI(cur->ai_next, afd, pton);
                         GET_PORT(cur->ai_next, servname);
-                        if ((pai->ai_flags & AI_CANONNAME)) {
-                                /*
-                                 * Set the numeric address itself as
-                                 * the canonical name, based on a
-                                 * clarification in rfc2553bis-03.
-                                 */
-                                GET_CANONNAME(cur->ai_next, canonname);
-                        }
+                        /*
+                         * Set the numeric address itself as
+                         * the canonical name, based on a
+                         * clarification in rfc2553bis-03.
+                         */
+                        GET_CANONNAME(cur->ai_next, canonname);
+
                         while (cur && cur->ai_next)
                                 cur = cur->ai_next;
                 } else
@@ -764,7 +765,7 @@ explore_numeric_scope(const struct addrinfo *pai, const char *hostname,
 static int
 get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str)
 {
-        if ((pai->ai_flags & AI_CANONNAME) != 0) {
+        if ((pai->ai_flags & (AI_CANONNAME | AI_FQDN)) != 0) {
                 ai->ai_canonname = strdup(str);
                 if (ai->ai_canonname == NULL)
                         return EAI_MEMORY;
@@ -1129,7 +1130,7 @@ getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
                         haveanswer++;
         }
         if (haveanswer) {
-                if (!canonname)
+                if (!canonname || (pai->ai_flags & AI_FQDN) != 0)
                         (void)get_canonname(pai, sentinel.ai_next, qname);
                 else
                         (void)get_canonname(pai, sentinel.ai_next, canonname);
@@ -1275,11 +1276,9 @@ found:
                 /* cover it up */
                 res->ai_flags = pai->ai_flags;
 
-                if (pai->ai_flags & AI_CANONNAME) {
-                        if (get_canonname(pai, res, cname) != 0) {
-                                freeaddrinfo(res0);
-                                goto again;
-                        }
+                if (get_canonname(pai, res, cname) != 0) {
+                        freeaddrinfo(res0);
+                        goto again;
                 }
         }
         return res0;
@@ -1369,8 +1368,7 @@ nextline:
                         /* cover it up */
                         res->ai_flags = pai->ai_flags;
 
-                        if (pai->ai_flags & AI_CANONNAME)
-                                (void)get_canonname(pai, res, canonname);
+                        (void)get_canonname(pai, res, canonname);
                 }
         } else
                 res0 = NULL;