* sendto_kdc.c (DEFAULT_UDP_PREF_LIMIT, HARD_UDP_LIMIT): New macros.

(debug_log_connect): Look up "udp_preference_limit" in libdefaults part of
profile; try TCP before UDP if the packet size is larger than specified.  Don't
try UDP at all if the packet is over about 32K.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@14732 dc483132-0cff-0310-8789-dd5450dbe970

diff --git a/src/lib/krb5/os/ChangeLog b/src/lib/krb5/os/ChangeLog
index e13daf397a482d9c5157d82b284b0264da601d06..2cd48383bf1ce488709b9c19576d7c5ab64d8f22 100644 (file)
--- a/src/lib/krb5/os/ChangeLog
+++ b/src/lib/krb5/os/ChangeLog
@@ -1,3 +1,12 @@
+2002-08-15  Ken Raeburn  <raeburn@mit.edu>
+
+       * sendto_kdc.c (DEFAULT_UDP_PREF_LIMIT, HARD_UDP_LIMIT): New
+       macros.
+       (debug_log_connect): Look up "udp_preference_limit" in libdefaults
+       part of profile; try TCP before UDP if the packet size is larger
+       than specified.  Don't try UDP at all if the packet is over about
+       32K.
+
 2002-07-23  Ezra Peisach  <epeisach@bu.edu>
 
        * localaddr.c (get_localaddrs): Add prototype before being used

diff --git a/src/lib/krb5/os/sendto_kdc.c b/src/lib/krb5/os/sendto_kdc.c
index 2d64ac3e3a268518d1144111b8cc06b6c14d85d0..4f22b4fa184204e295cade5c9bbbf5a47234dcef 100644 (file)
--- a/src/lib/krb5/os/sendto_kdc.c
+++ b/src/lib/krb5/os/sendto_kdc.c
@@ -55,6 +55,9 @@
 #endif
 #endif
 
+#define DEFAULT_UDP_PREF_LIMIT  1465
+#define HARD_UDP_LIMIT         32700
+
 /*
  * send the formatted request 'message' to a KDC for realm 'realm' and
  * return the response (if any) in 'reply'.
@@ -83,8 +86,10 @@ krb5_sendto_kdc (context, message, realm, reply, use_master, tcp_only)
      */
 
     /*
-     * DO NOT depend on this staying as two separate loops.  We may change
-     * the order, or we may integrate them into one loop.
+     * DO NOT depend on this staying as two separate loops.  We may
+     * change the order, or we may integrate them into one loop.
+     * Integration is preferred, since it would keep the total delay
+     * time down when a timeout occurs.
      *
      * BUG: This code won't return "interesting" errors (e.g., out of mem,
      * bad config file) from locate_kdc.  KRB5_REALM_CANT_RESOLVE can be
@@ -102,10 +107,28 @@ krb5_sendto_kdc (context, message, realm, reply, use_master, tcp_only)
     fprintf(stderr, "\", use_master=%d, tcp_only=%d)\n", use_master, tcp_only);
 #endif
 
+    if (!tcp_only && context->udp_pref_limit < 0) {
+       int tmp;
+       retval = profile_get_integer(context->profile,
+                                    "libdefaults", "udp_preference_limit", 0,
+                                    DEFAULT_UDP_PREF_LIMIT, &tmp);
+       if (retval)
+           return retval;
+       if (tmp < 0)
+           tmp = DEFAULT_UDP_PREF_LIMIT;
+       else if (tmp > HARD_UDP_LIMIT)
+           /* In the unlikely case that a *really* big value is
+              given, let 'em use as big as we think we can support.
+              Well, almost 64K is probably doable, but let's be, um,
+              a little conservative.  */
+           tmp = HARD_UDP_LIMIT;
+       context->udp_pref_limit = tmp;
+    }
+
     retval = (use_master ? KRB5_KDC_UNREACH : KRB5_REALM_UNKNOWN);
 
     if (!tcp_only
-       && message->length < 1500
+       && message->length <= context->udp_pref_limit
        && ! krb5_locate_kdc(context, realm, &addrs, use_master, SOCK_DGRAM)) {
        if (addrs.naddrs > 0) {
            retval = krb5int_sendto_udp (context, message, &addrs, reply,
@@ -123,6 +146,18 @@ krb5_sendto_kdc (context, message, realm, reply, use_master, tcp_only)
                return 0;
        }
     }
+    if (!tcp_only
+       && message->length > context->udp_pref_limit
+       && message->length <= HARD_UDP_LIMIT
+       && ! krb5_locate_kdc(context, realm, &addrs, use_master, SOCK_DGRAM)) {
+       if (addrs.naddrs > 0) {
+           retval = krb5int_sendto_udp (context, message, &addrs, reply,
+                                        0, 0);
+           krb5int_free_addrlist (&addrs);
+           if (retval == 0)
+               return 0;
+       }
+    }
 
     return retval;
 }