Get the client side of receiving an IPv6 address to work

This makes it so we can handle getting an IPv6 in the 3 different
formats we specified it for in RESOLVED cells,
END_STREAM_REASON_EXITPOLICY cells, and CONNECTED cells.

We don't cache IPv6 addresses yet, since proposal 205 isn't
implemented.

There's a refactored function for parsing connected cells; it has unit
tests.

1 files changed, 104 insertions, 30 deletions

diff --git a/src/or/relay.c b/src/or/relay.c
index 76e9d2550b..a05e955ecd 100644
--- a/src/or/relay.c
+++ b/src/or/relay.c
@@ -705,21 +705,37 @@ connection_ap_process_end_not_open(
     switch (reason) {
       case END_STREAM_REASON_EXITPOLICY:
         if (rh->length >= 5) {
-          uint32_t addr = ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+1));
-          int ttl;
-          if (!addr) {
+          tor_addr_t addr;
+          int ttl = -1;
+          tor_addr_make_unspec(&addr);
+          if (rh->length == 5 || rh->length == 9) {
+            tor_addr_from_ipv4n(&addr,
+                                get_uint32(cell->payload+RELAY_HEADER_SIZE+1));
+            if (rh->length == 9)
+              ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+5));
+          } else if (rh->length == 17 || rh->length == 21) {
+            tor_addr_from_ipv6_bytes(&addr,
+                                (char*)(cell->payload+RELAY_HEADER_SIZE+1));
+            if (rh->length == 21)
+              ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+17));
+          }
+          if (tor_addr_is_null(&addr)) {
             log_info(LD_APP,"Address '%s' resolved to 0.0.0.0. Closing,",
                      safe_str(conn->socks_request->address));
             connection_mark_unattached_ap(conn, END_STREAM_REASON_TORPROTOCOL);
             return 0;
           }
-          if (rh->length >= 9)
-            ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+5));
-          else
-            ttl = -1;
 
+          if ((tor_addr_family(&addr) == AF_INET && !conn->ipv4_traffic_ok) ||
+              (tor_addr_family(&addr) == AF_INET6 && !conn->ipv6_traffic_ok)) {
+            log_fn(LOG_PROTOCOL_WARN, LD_APP,
+                   "Got an EXITPOLICY failure on a connection with a "
+                   "mismatched family. Closing.");
+            connection_mark_unattached_ap(conn, END_STREAM_REASON_TORPROTOCOL);
+            return 0;
+          }
           if (get_options()->ClientDNSRejectInternalAddresses &&
-              is_internal_IP(addr, 0)) {
+              tor_addr_is_internal(&addr, 0)) {
             log_info(LD_APP,"Address '%s' resolved to internal. Closing,",
                      safe_str(conn->socks_request->address));
             connection_mark_unattached_ap(conn, END_STREAM_REASON_TORPROTOCOL);
@@ -727,7 +743,7 @@ connection_ap_process_end_not_open(
           }
 
           client_dns_set_addressmap(circ,
-                                    conn->socks_request->address, addr,
+                                    conn->socks_request->address, &addr,
                                     conn->chosen_exit_name, ttl);
         }
         /* check if he *ought* to have allowed it */
@@ -830,20 +846,56 @@ connection_ap_process_end_not_open(
 }
 
 /** Helper: change the socks_request->address field on conn to the
- * dotted-quad representation of <b>new_addr</b> (given in host order),
+ * dotted-quad representation of <b>new_addr</b>,
  * and send an appropriate REMAP event. */
 static void
-remap_event_helper(entry_connection_t *conn, uint32_t new_addr)
+remap_event_helper(entry_connection_t *conn, const tor_addr_t *new_addr)
 {
-  struct in_addr in;
-
-  in.s_addr = htonl(new_addr);
-  tor_inet_ntoa(&in, conn->socks_request->address,
-                sizeof(conn->socks_request->address));
+  tor_addr_to_str(conn->socks_request->address, new_addr,
+                  sizeof(conn->socks_request->address),
+                  0); /* XXXXX Should decorate be 1? */
   control_event_stream_status(conn, STREAM_EVENT_REMAP,
                               REMAP_STREAM_SOURCE_EXIT);
 }
 
+/**DOCDOC*/
+int
+connected_cell_parse(const relay_header_t *rh, const cell_t *cell,
+                     tor_addr_t *addr_out, int *ttl_out)
+{
+  uint32_t bytes;
+  const uint8_t *payload = cell->payload + RELAY_HEADER_SIZE;
+
+  tor_addr_make_unspec(addr_out);
+  *ttl_out = -1;
+  if (rh->length == 0)
+    return 0;
+  if (rh->length < 4)
+    return -1;
+  bytes = ntohl(get_uint32(payload));
+
+  /* If bytes is 0, this is maybe a v6 address. Otherwise it's a v4 address */
+  if (bytes != 0) {
+    /* v4 address */
+    tor_addr_from_ipv4h(addr_out, bytes);
+    if (rh->length >= 8) {
+      bytes = ntohl(get_uint32(payload + 4));
+      if (bytes <= INT32_MAX)
+        *ttl_out = bytes;
+    }
+  } else {
+    if (rh->length < 25) /* 4 bytes of 0s, 1 addr, 16 ipv4, 4 ttl. */
+      return -1;
+    if (get_uint8(payload + 4) != 6)
+      return -1;
+    tor_addr_from_ipv6_bytes(addr_out, (char*)(payload + 5));
+    bytes = ntohl(get_uint32(payload + 21));
+    if (bytes <= INT32_MAX)
+      *ttl_out = (int) bytes;
+  }
+  return 0;
+}
+
 /** An incoming relay cell has arrived from circuit <b>circ</b> to
  * stream <b>conn</b>.
  *
@@ -874,6 +926,8 @@ connection_edge_process_relay_cell_not_open(
 
   if (conn->base_.type == CONN_TYPE_AP &&
       rh->command == RELAY_COMMAND_CONNECTED) {
+    tor_addr_t addr;
+    int ttl;
     entry_connection_t *entry_conn = EDGE_TO_ENTRY_CONN(conn);
     tor_assert(CIRCUIT_IS_ORIGIN(circ));
     if (conn->base_.state != AP_CONN_STATE_CONNECT_WAIT) {
@@ -884,27 +938,41 @@ connection_edge_process_relay_cell_not_open(
     conn->base_.state = AP_CONN_STATE_OPEN;
     log_info(LD_APP,"'connected' received after %d seconds.",
              (int)(time(NULL) - conn->base_.timestamp_lastread));
-    if (rh->length >= 4) {
-      uint32_t addr = ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE));
-      int ttl;
-      if (!addr || (get_options()->ClientDNSRejectInternalAddresses &&
-                    is_internal_IP(addr, 0))) {
+    if (connected_cell_parse(rh, cell, &addr, &ttl) < 0) {
+      log_fn(LOG_PROTOCOL_WARN, LD_APP,
+             "Got a badly formatted connected cell. Closing.");
+      connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL);
+      connection_mark_unattached_ap(entry_conn, END_STREAM_REASON_TORPROTOCOL);
+    }
+    if (tor_addr_family(&addr) != AF_UNSPEC) {
+      const sa_family_t family = tor_addr_family(&addr);
+      if (tor_addr_is_null(&addr) ||
+          (get_options()->ClientDNSRejectInternalAddresses &&
+           tor_addr_is_internal(&addr, 0))) {
         log_info(LD_APP, "...but it claims the IP address was %s. Closing.",
-                 fmt_addr32(addr));
+                 fmt_addr(&addr));
+        connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL);
+        connection_mark_unattached_ap(entry_conn,
+                                      END_STREAM_REASON_TORPROTOCOL);
+        return 0;
+      }
+
+      if ((family == AF_INET && ! entry_conn->ipv4_traffic_ok) ||
+          (family == AF_INET6 && ! entry_conn->ipv6_traffic_ok)) {
+        log_fn(LOG_PROTOCOL_WARN, LD_APP,
+               "Got a connected cell to %s with unsupported address family."
+               " Closing.", fmt_addr(&addr));
         connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL);
         connection_mark_unattached_ap(entry_conn,
                                       END_STREAM_REASON_TORPROTOCOL);
         return 0;
       }
-      if (rh->length >= 8)
-        ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+4));
-      else
-        ttl = -1;
+
       client_dns_set_addressmap(TO_ORIGIN_CIRCUIT(circ),
-                                entry_conn->socks_request->address, addr,
+                                entry_conn->socks_request->address, &addr,
                                 entry_conn->chosen_exit_name, ttl);
 
-      remap_event_helper(entry_conn, addr);
+      remap_event_helper(entry_conn, &addr);
     }
     circuit_log_path(LOG_INFO,LD_APP,TO_ORIGIN_CIRCUIT(circ));
     /* don't send a socks reply to transparent conns */
@@ -994,8 +1062,14 @@ connection_edge_process_relay_cell_not_open(
                    ttl,
                    -1);
     if (answer_type == RESOLVED_TYPE_IPV4 && answer_len == 4) {
-      uint32_t addr = ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+2));
-      remap_event_helper(entry_conn, addr);
+      tor_addr_t addr;
+      tor_addr_from_ipv4n(&addr, get_uint32(cell->payload+RELAY_HEADER_SIZE+2));
+      remap_event_helper(entry_conn, &addr);
+    } else if (answer_type == RESOLVED_TYPE_IPV6 && answer_len == 16) {
+      tor_addr_t addr;
+      tor_addr_from_ipv6_bytes(&addr,
+                               (char*)(cell->payload+RELAY_HEADER_SIZE+2));
+      remap_event_helper(entry_conn, &addr);
     }
     connection_mark_unattached_ap(entry_conn,
                               END_STREAM_REASON_DONE |