[or-cvs] authorities do not replace server descriptors where nothing...

[Nick Mathewson]

Update of /home/or/cvsroot/tor/src/or
In directory moria:/tmp/cvs-serv17903/src/or

Modified Files:
	directory.c dirserv.c routerlist.c 
Log Message:
authorities do not replace server descriptors where nothing semantically relevant has changed since the last upload.

Index: directory.c
===================================================================
RCS file: /home/or/cvsroot/tor/src/or/directory.c,v
retrieving revision 1.303
retrieving revision 1.304
diff -u -d -r1.303 -r1.304
--- directory.c	5 Oct 2005 20:45:18 -0000	1.303
+++ directory.c	12 Oct 2005 18:25:25 -0000	1.304
@@ -1441,7 +1441,7 @@
   if (!authdir_mode(get_options())) {
     /* we just provide cached directories; we don't want to
      * receive anything. */
-    write_http_status_line(conn, 400, "Nonauthoritative directory does not not store server descriptors.");
+    write_http_status_line(conn, 400, "Nonauthoritative directory does not accept posted server descriptors.");
     return 0;
   }
 

Index: dirserv.c
===================================================================
RCS file: /home/or/cvsroot/tor/src/or/dirserv.c,v
retrieving revision 1.247
retrieving revision 1.248
diff -u -d -r1.247 -r1.248
--- dirserv.c	8 Oct 2005 06:02:41 -0000	1.247
+++ dirserv.c	12 Oct 2005 18:25:25 -0000	1.248
@@ -439,7 +439,7 @@
 dirserv_add_descriptor(const char *desc, const char **msg)
 {
   int r;
-  routerinfo_t *ri = NULL;
+  routerinfo_t *ri = NULL, *ri_old = NULL;
   tor_assert(msg);
   *msg = NULL;
 
@@ -450,6 +450,19 @@
     *msg = "Rejected: Couldn't parse server descriptor.";
     return -2;
   }
+  /* Check whether this descriptor is semantically identical to the last one
+   * from this server.  (We do this here and not in router_add_to_routerlist
+   * because we want to be able to accept the newest router descriptor that
+   * another authority has, so we all converge on the same one.) */
+  ri_old = router_get_by_digest(ri->identity_digest);
+  if (ri_old && ri_old->published_on < ri->published_on &&
+      router_differences_are_cosmetic(ri_old, ri)) {
+    log_fn(LOG_INFO,
+           "Not replacing descriptor from '%s'; differences are cosmetic.",
+           ri->nickname);
+    *msg = "Not replacing router descriptor; no information has changed since the last one with this identity.";
+    return 0;
+  }
   if ((r = router_add_to_routerlist(ri, msg, 0))<0) {
     return r == -1 ? 0 : -1;
   } else {

Index: routerlist.c
===================================================================
RCS file: /home/or/cvsroot/tor/src/or/routerlist.c,v
retrieving revision 1.338
retrieving revision 1.339
diff -u -d -r1.338 -r1.339
--- routerlist.c	12 Oct 2005 17:16:25 -0000	1.338
+++ routerlist.c	12 Oct 2005 18:25:25 -0000	1.339
@@ -2533,8 +2533,6 @@
   if (!routerstatus_list)
     return;
 
-  log_fn(LOG_NOTICE, "Here, %d %d", reset_failures, assume_recognized);
-
   SMARTLIST_FOREACH(routers, routerinfo_t *, router,
   {
     rs = router_get_combined_status_by_digest(router->identity_digest);
@@ -2864,11 +2862,19 @@
 int
 router_differences_are_cosmetic(routerinfo_t *r1, routerinfo_t *r2)
 {
+  tor_assert(r1 && r2);
+
   /* post-0.1.1.6 servers know what they're doing. */
   if (tor_version_as_new_as(r1->platform, "0.1.1.6-alpha") ||
       tor_version_as_new_as(r1->platform, "0.1.1.6-alpha"))
     return 0;
 
+  if (r1->published_on > r2->published_on) {
+    routerinfo_t *ri_tmp = r2;
+    r2 = r1;
+    r1 = ri_tmp;
+  }
+
   /* If any key fields differ, they're different. */
   if (strcasecmp(r1->address, r2->address) ||
       strcasecmp(r1->nickname, r2->nickname) ||
@@ -2901,8 +2907,12 @@
     return 0;
 
   /* Did more than 6 hours pass? */
-  if (r1->published_on + 6*60*60 < r2->published_on ||
-      r2->published_on + 6*60*60 < r1->published_on)
+  if (r1->published_on + 6*60*60 < r2->published_on)
+    return 0;
+
+  /* Did uptime fail to increase by approximately the amount we would think,
+   * give or take 30 minutes? */
+  if (abs(r2->uptime - (r1->uptime + (r2->published_on-r1->published_on)))>30*60)
     return 0;
 
   /* Otherwise, the difference is cosmetic. */