Add options to turn DNS cache use on or off per client port.

(This is part 1 of making DNS cache use enabled/disabled on a
per-client port basis.  These options are shuffled around correctly,
but don't do anything yet.)

src/or/config.c

@@ -4790,6 +4790,7 @@ parse_port_config(smartlist_t *out,
         cfg->isolation_flags = ISO_DEFAULT;
         cfg->no_advertise = 1;
         cfg->ipv4_traffic = 1;
+        cfg->cache_ipv4_answers = cfg->use_cached_ipv4_answers = 1;
         smartlist_add(out, cfg);
       }
     }
@@ -4814,6 +4815,7 @@ parse_port_config(smartlist_t *out,
        cfg->session_group = SESSION_GROUP_UNSET;
        cfg->isolation_flags = ISO_DEFAULT;
        cfg->ipv4_traffic = 1;
+       cfg->cache_ipv4_answers = cfg->use_cached_ipv4_answers = 1;
        smartlist_add(out, cfg);
     }
     return 0;
@@ -4834,7 +4836,9 @@ parse_port_config(smartlist_t *out,
     int ok;
     int no_listen = 0, no_advertise = 0, all_addrs = 0,
       bind_ipv4_only = 0, bind_ipv6_only = 0,
-      ipv4_traffic = 1, ipv6_traffic = 0, prefer_ipv6 = 0;
+      ipv4_traffic = 1, ipv6_traffic = 0, prefer_ipv6 = 0,
+      cache_ipv4 = 1, use_cached_ipv4 = 1,
+      cache_ipv6 = 0, use_cached_ipv6 = 0;
 
     smartlist_split_string(elts, ports->value, NULL,
                            SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
@@ -4971,6 +4975,25 @@ parse_port_config(smartlist_t *out,
             continue;
           }
         }
+        if (!strcasecmp(elt, "CacheIPv4DNS")) {
+          cache_ipv4 = ! no;
+          continue;
+        } else if (!strcasecmp(elt, "CacheIPv6DNS")) {
+          cache_ipv6 = ! no;
+          continue;
+        } else if (!strcasecmp(elt, "CacheDNS")) {
+          cache_ipv4 = cache_ipv6 = ! no;
+          continue;
+        } else if (!strcasecmp(elt, "UseIPv4Cache")) {
+          use_cached_ipv4 = ! no;
+          continue;
+        } else if (!strcasecmp(elt, "UseIPv6Cache")) {
+          use_cached_ipv6 = ! no;
+          continue;
+        } else if (!strcasecmp(elt, "UseDNSCache")) {
+          use_cached_ipv4 = use_cached_ipv6 = ! no;
+          continue;
+        }
 
         if (!strcasecmpend(elt, "s"))
           elt[strlen(elt)-1] = '\0'; /* kill plurals. */
@@ -5024,6 +5047,10 @@ parse_port_config(smartlist_t *out,
       cfg->ipv4_traffic = ipv4_traffic;
       cfg->ipv6_traffic = ipv6_traffic;
       cfg->prefer_ipv6 = prefer_ipv6;
+      cfg->cache_ipv4_answers = cache_ipv4;
+      cfg->cache_ipv6_answers = cache_ipv6;
+      cfg->use_cached_ipv4_answers = use_cached_ipv4;
+      cfg->use_cached_ipv6_answers = use_cached_ipv6;
 
       smartlist_add(out, cfg);
     }

src/or/connection.c

@@ -1130,6 +1130,10 @@ connection_listener_new(const struct sockaddr *listensockaddr,
     lis_conn->socks_ipv4_traffic = 1;
     lis_conn->socks_ipv6_traffic = 1;
   }
+  lis_conn->cache_ipv4_answers = port_cfg->cache_ipv4_answers;
+  lis_conn->cache_ipv6_answers = port_cfg->cache_ipv6_answers;
+  lis_conn->use_cached_ipv4_answers = port_cfg->use_cached_ipv4_answers;
+  lis_conn->use_cached_ipv6_answers = port_cfg->use_cached_ipv6_answers;
 
   if (connection_add(conn) < 0) { /* no space, forget it */
     log_warn(LD_NET,"connection_add for listener failed. Giving up.");
@@ -1366,6 +1370,13 @@ connection_init_accepted_conn(connection_t *conn,
       TO_ENTRY_CONN(conn)->ipv4_traffic_ok = listener->socks_ipv4_traffic;
       TO_ENTRY_CONN(conn)->ipv6_traffic_ok = listener->socks_ipv6_traffic;
       TO_ENTRY_CONN(conn)->prefer_ipv6_traffic = listener->socks_prefer_ipv6;
+      TO_ENTRY_CONN(conn)->cache_ipv4_answers = listener->cache_ipv4_answers;
+      TO_ENTRY_CONN(conn)->cache_ipv6_answers = listener->cache_ipv6_answers;
+      TO_ENTRY_CONN(conn)->use_cached_ipv4_answers =
+        listener->use_cached_ipv4_answers;
+      TO_ENTRY_CONN(conn)->use_cached_ipv6_answers =
+        listener->use_cached_ipv6_answers;
+
       switch (TO_CONN(listener)->type) {
         case CONN_TYPE_AP_LISTENER:
           conn->state = AP_CONN_STATE_SOCKS_WAIT;

src/or/or.h

@@ -1237,6 +1237,12 @@ typedef struct listener_connection_t {
    * addresses? */
   unsigned int socks_prefer_ipv6 : 1;
 
+  /*DOCDOC*/
+  unsigned int cache_ipv4_answers : 1;
+  unsigned int cache_ipv6_answers : 1;
+  unsigned int use_cached_ipv4_answers : 1;
+  unsigned int use_cached_ipv6_answers : 1;
+
 } listener_connection_t;
 
 /** Minimum length of the random part of an AUTH_CHALLENGE cell. */
@@ -1545,6 +1551,12 @@ typedef struct entry_connection_t {
   /** Should we say we prefer IPv6 traffic? */
   unsigned int prefer_ipv6_traffic : 1;
 
+  /* DOCDOC*/
+  unsigned int cache_ipv4_answers : 1;
+  unsigned int cache_ipv6_answers : 1;
+  unsigned int use_cached_ipv4_answers : 1;
+  unsigned int use_cached_ipv6_answers : 1;
+
 } entry_connection_t;
 
 /** Subtype of connection_t for an "directory connection" -- that is, an HTTP
@@ -3084,10 +3096,18 @@ typedef struct port_cfg_t {
   unsigned int all_addrs : 1;
   unsigned int bind_ipv4_only : 1;
   unsigned int bind_ipv6_only : 1;
+
+  /* Client port types only: */
   unsigned int ipv4_traffic : 1;
   unsigned int ipv6_traffic : 1;
   unsigned int prefer_ipv6 : 1;
 
+  /* DOCDOC */
+  unsigned int cache_ipv4_answers : 1;
+  unsigned int cache_ipv6_answers : 1;
+  unsigned int use_cached_ipv4_answers : 1;
+  unsigned int use_cached_ipv6_answers : 1;
+
   /* Unix sockets only: */
   /** Path for an AF_UNIX address */
   char unix_addr[FLEXIBLE_ARRAY_MEMBER];