From 49ff374f565b46d63678d1ea92eba436eacaa8cc Mon Sep 17 00:00:00 2001
From: Jeffrey Hutzelman <jhutz@cmu.edu>
Date: Sat, 5 Jan 2013 15:29:16 -0500
Subject: Abstract realm server usability test

Whether a particular server is usable currently depends only on whether we
have successfully obtained its IP address.  However, eventually it will also
depend on additional factors such as whether the server has been deleted from
the realm.list.  To ease that transition, replace the 'usable' flag with a
'got_addr' flag (which is set when the address lookup succeeds), and add a
new function to test whether a server is usable.
---
 server/realm.c   | 16 +++++++++++-----
 server/zserver.h |  2 +-
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/server/realm.c b/server/realm.c
index d4eeff6..60b2783 100644
--- a/server/realm.c
+++ b/server/realm.c
@@ -76,6 +76,12 @@ static Code_t ticket_retrieve(ZRealm *realm);
 static int ticket_lookup(char *realm);
 #endif
 
+static int
+is_usable(ZRealm_server *srvr)
+{
+    return srvr->got_addr;
+}
+
 static int
 realm_get_idx_by_addr(ZRealm *realm,
 		      struct sockaddr_in *who)
@@ -85,7 +91,7 @@ realm_get_idx_by_addr(ZRealm *realm,
 
     /* loop through the realms */
     for (srvr = realm->srvrs, b = 0; b < realm->count; b++, srvr++) {
-	if (!srvr->usable)
+	if (!is_usable(srvr))
 	    continue;
 	if (srvr->addr.sin_addr.s_addr == who->sin_addr.s_addr)
 	    return(b);
@@ -107,7 +113,7 @@ realm_next_idx_by_idx(realm, idx)
     while (a > 0) { a--; srvr++; }
 
     for (srvr, b = idx; b < realm->count; b++, srvr++) {
-	if (!srvr->usable)
+	if (!is_usable(srvr))
 	    continue;
 	if (!srvr->dontsend)
 	    return(b);
@@ -116,7 +122,7 @@ realm_next_idx_by_idx(realm, idx)
     /* recycle */
     if (idx != 0)
 	for (srvr = realm->srvrs, b = 0; b < idx; b++, srvr++) {
-	    if (!srvr->usable)
+	    if (!is_usable(srvr))
 		continue;
 	    if (!srvr->dontsend)
 		return(b);
@@ -335,7 +341,7 @@ realm_which_realm(struct sockaddr_in *who)
 	for (srvr = otherrealms[a]->srvrs, b = 0;
 	     b < otherrealms[a]->count;
 	     b++, srvr++) {
-	    if (!srvr->usable)
+	    if (!is_usable(srvr))
 		continue;
 	    if (srvr->addr.sin_addr.s_addr == who->sin_addr.s_addr)
 		return(otherrealms[a]);
@@ -586,7 +592,7 @@ realm_init(void)
 		/* use the server port */
 		srvr->addr.sin_port = srv_addr.sin_port;
 		srvr->addr.sin_family = AF_INET;
-		srvr->usable = 1;
+		srvr->got_addr = 1;
 	    } else
 		syslog(LOG_WARNING, "hostname failed, %s", srvr->name->string);
 	}
diff --git a/server/zserver.h b/server/zserver.h
index fc6f847..ecdd06e 100644
--- a/server/zserver.h
+++ b/server/zserver.h
@@ -114,8 +114,8 @@ struct _Destlist {
 struct _ZRealm_server {
     String *name;			/* server's hostname */
     struct sockaddr_in addr;		/* server's address */
-    unsigned int usable :1;             /* set once entry is usable */
     unsigned int dontsend :1;		/* private server, do not send */
+    unsigned int got_addr :1;		/* IP address is valid */
 };
 
 struct _ZRealm {
-- 
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