quick-and-dirty dir policy since the dirservers are getting hammered

nick, could you abstract this sometime so we don't repeat the
sockspolicy code twice?


svn:r2589

src/or/config.c

@@ -236,6 +236,7 @@ config_assign(or_options_t *options, struct config_line_t *list)
       config_compare(list, "DirPort",        CONFIG_TYPE_UINT, &options->DirPort) ||
       config_compare(list, "DirBindAddress", CONFIG_TYPE_LINELIST, &options->DirBindAddress) ||
       config_compare(list, "DirFetchPostPeriod",CONFIG_TYPE_UINT, &options->DirFetchPostPeriod) ||
+      config_compare(list, "DirPolicy",      CONFIG_TYPE_LINELIST, &options->DirPolicy) ||
       config_compare(list, "DirServer",      CONFIG_TYPE_LINELIST, &options->DirServers) ||
 
       config_compare(list, "ExitNodes",      CONFIG_TYPE_STRING, &options->ExitNodes) ||
@@ -479,6 +480,7 @@ free_options(or_options_t *options)
   config_free_lines(options->DirBindAddress);
   config_free_lines(options->ExitPolicy);
   config_free_lines(options->SocksPolicy);
+  config_free_lines(options->DirPolicy);
   config_free_lines(options->DirServers);
   config_free_lines(options->RecommendedVersions);
   config_free_lines(options->NodeFamilies);
@@ -487,7 +489,7 @@ free_options(or_options_t *options)
     SMARTLIST_FOREACH(options->RedirectExitList,
                       exit_redirect_t *, p, tor_free(p));
     smartlist_free(options->RedirectExitList);
-    options->RedirectExitList = NULL;                      
+    options->RedirectExitList = NULL;
   }
   if (options->FirewallPorts) {
     SMARTLIST_FOREACH(options->FirewallPorts, char *, cp, tor_free(cp));

src/or/connection.c

@@ -420,6 +420,15 @@ static int connection_handle_listener_read(connection_t *conn, int new_type) {
       return 0;
     }
   }
+  if(new_type == CONN_TYPE_DIR) {
+    /* check dirpolicy to see if we should accept it */
+    if(dir_policy_permits_address(ntohl(remote.sin_addr.s_addr)) == 0) {
+      log_fn(LOG_WARN,"Denying dir connection from address %s.",
+             inet_ntoa(remote.sin_addr));
+      tor_close_socket(news);
+      return 0;
+    }
+  }
 
   newconn = connection_new(new_type);
   newconn->s = news;

src/or/directory.c

@@ -48,6 +48,8 @@ static int directory_handle_command(connection_t *conn);
 
 extern or_options_t options; /* command-line and config-file options */
 
+static struct exit_policy_t *dir_policy = NULL;
+
 #if 0 /* commented out for now, since for now what clients send is
          different from what servers want to receive */
 /** URL for publishing rendezvous descriptors. */
@@ -63,6 +65,48 @@ char rend_fetch_url[] = "/tor/rendezvous/";
 
 /********* END VARIABLES ************/
 
+/** A helper function for dir_policy_permits_address() below.
+ *
+ * Parse options.DirPolicy in the same way that the exit policy
+ * is parsed, and put the processed version in &dir_policy.
+ * Ignore port specifiers.
+ */
+static void parse_dir_policy(void)
+{
+  struct exit_policy_t *n;
+  if (dir_policy) {
+    exit_policy_free(dir_policy);
+    dir_policy = NULL;
+  }
+  config_parse_exit_policy(options.DirPolicy, &dir_policy);
+  /* ports aren't used. */
+  for (n=dir_policy; n; n = n->next) {
+    n->prt_min = 1;
+    n->prt_max = 65535;
+  }
+}
+
+/** Return 1 if <b>addr</b> is permitted to connect to our dir port,
+ * based on <b>dir_policy</b>. Else return 0.
+ */
+int dir_policy_permits_address(uint32_t addr)
+{
+  int a;
+  if (options.DirPolicy && !dir_policy)
+    parse_dir_policy();
+
+  if(!dir_policy) /* 'no dir policy' means 'accept' */
+    return 1;
+  a = router_compare_addr_to_exit_policy(addr, 1, dir_policy);
+  if (a==-1)
+    return 0;
+  else if (a==0)
+    return 1;
+  tor_assert(a==1);
+  log_fn(LOG_WARN, "Got unexpected 'maybe' answer from dir policy");
+  return 0;
+}
+
 /** Start a connection to every known directory server, using
  * connection purpose 'purpose' and uploading the payload 'payload'
  * (length 'payload_len').  The purpose should be one of

src/or/or.h

@@ -860,6 +860,7 @@ typedef struct {
   int _AllowUnverified; /**< Bitmask; derived from AllowUnverifiedNodes; */
   struct config_line_t *ExitPolicy; /**< Lists of exit policy components. */
   struct config_line_t *SocksPolicy; /**< Lists of socks policy components */
+  struct config_line_t *DirPolicy; /**< Lists of dir policy components */
   /** Addresses to bind for listening for SOCKS connections. */
   struct config_line_t *SocksBindAddress;
   /** Addresses to bind for listening for OR connections. */
@@ -1191,6 +1192,7 @@ int assign_to_cpuworker(connection_t *cpuworker, unsigned char question_type,
 
 /********************************* directory.c ***************************/
 
+int dir_policy_permits_address(uint32_t addr);
 void directory_post_to_dirservers(uint8_t purpose, const char *payload,
                                   size_t payload_len);
 void directory_get_from_dirserver(uint8_t purpose, const char *payload,