Move in-addr.arpa parsing and generation into address.c, and simplify the code that does it elsewhere. Incidentally, this lets exit servers answer requests for ip6.arpa addresses.

svn:r17707

9 files changed, 258 insertions, 95 deletions

diff --git a/ChangeLog b/ChangeLog
index c867738432..7e0fe2325f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -46,6 +46,7 @@ Changes in version 0.2.1.9-alpha - 2008-12-2?
     - Optimize out calls to time(NULL) that occur for every IO operation, or
       for every cell. On systems where time() is a slow syscalls, this will
       be slightly helpful.
+    - Exit servers can now answer resolve requests for ip6.arpa addresses.
 
   o Minor features (controller):
     - New CONSENSUS_ARRIVED event to note when a new consensus has
diff --git a/src/common/address.c b/src/common/address.c
index 9c7da1af2a..efbc79c2be 100644
--- a/src/common/address.c
+++ b/src/common/address.c
@@ -344,6 +344,139 @@ tor_addr_to_str(char *dest, const tor_addr_t *addr, int len, int decorate)
   return ptr;
 }
 
+/** Parse an .in-addr.arpa or .ip6.arpa address from <b>address</b>.  Return 0
+ * if this is not an .in-addr.arpa address or an .ip6.arpa address.  Return -1
+ * if this is an ill-formed .in-addr.arpa address or an .ip6.arpa address.
+ * Also return -1 if <b>family</b> is not AF_UNSPEC, and the parsed address
+ * family does not match <b>family</b>.  On success, return 1, and store the
+ * result, if any, into <b>result</b>, if provided.
+ *
+ * If <b>accept_regular</b> is set and the address is in neither recognized
+ * reverse lookup hostname format, try parsing the address as a regular
+ * IPv4 or IPv6 address too.
+ */
+int
+tor_addr_parse_reverse_lookup_name(tor_addr_t *result, const char *address,
+                                   int family, int accept_regular)
+{
+  if (!strcasecmpend(address, ".in-addr.arpa")) {
+    /* We have an in-addr.arpa address. */
+    char buf[INET_NTOA_BUF_LEN];
+    size_t len;
+    struct in_addr inaddr;
+    if (family == AF_INET6)
+      return -1;
+
+    len = strlen(address) - strlen(".in-addr.arpa");
+    if (len >= INET_NTOA_BUF_LEN)
+      return -1; /* Too long. */
+
+    memcpy(buf, address, len);
+    buf[len] = '\0';
+    if (tor_inet_aton(buf, &inaddr) == 0)
+      return -1; /* malformed. */
+
+    /* reverse the bytes */
+    inaddr.s_addr = (((inaddr.s_addr & 0x000000fful) << 24)
+                     |((inaddr.s_addr & 0x0000ff00ul) << 8)
+                     |((inaddr.s_addr & 0x00ff0000ul) >> 8)
+                     |((inaddr.s_addr & 0xff000000ul) >> 24));
+
+    if (result) {
+      memset(result, 0, sizeof(tor_addr_t));
+      result->family = AF_INET;
+      result->addr.in_addr.s_addr = inaddr.s_addr;
+    }
+    return 1;
+  }
+
+  if (!strcasecmpend(address, ".ip6.arpa")) {
+    const char *cp;
+    int i;
+    int n0, n1;
+    struct in6_addr in6;
+
+    if (family == AF_INET)
+      return -1;
+
+    cp = address;
+    for (i = 0; i < 16; ++i) {
+      n0 = hex_decode_digit(*cp++); /* The low-order nybble appears first. */
+      if (*cp++ != '.') return -1;  /* Then a dot. */
+      n1 = hex_decode_digit(*cp++); /* The high-order nybble appears first. */
+      if (*cp++ != '.') return -1;  /* Then another dot. */
+      if (n0<0 || n1 < 0) /* Both nybbles must be hex. */
+        return -1;
+
+      /* We don't check the length of the string in here.  But that's okay,
+       * since we already know that the string ends with ".ip6.arpa", and
+       * there is no way to frameshift .ip6.arpa so it fits into the pattern
+       * of hexdigit, period, hexdigit, period that we enforce above.
+       */
+
+      /* Assign from low-byte to high-byte. */
+      in6.s6_addr[15-i] = n0 | (n1 << 4);
+    }
+    if (strcasecmp(cp, "ip6.arpa"))
+      return -1;
+
+    if (result) {
+      result->family = AF_INET6;
+      memcpy(&result->addr.in6_addr, &in6, sizeof(in6));
+    }
+    return 1;
+  }
+
+  if (accept_regular) {
+    tor_addr_t tmp;
+    int r = tor_addr_from_str(&tmp, address);
+    if (r < 0)
+      return 0;
+    if (r != family && family != AF_UNSPEC)
+      return -1;
+
+    if (result)
+      memcpy(result, &tmp, sizeof(tor_addr_t));
+
+    return 1;
+  }
+
+  return 0;
+}
+
+/** Convert <b>addr</b> to an in-addr.arpa name or a .ip6.arpa name, and store
+ * the result in the <b>outlen</b>-byte buffer at <b>out</b>.  Return 0 on
+ * success, -1 on failure. */
+int
+tor_addr_to_reverse_lookup_name(char *out, size_t outlen,
+                                const tor_addr_t *addr)
+{
+  if (addr->family == AF_INET) {
+    uint32_t a = tor_addr_to_ipv4h(addr);
+
+    return tor_snprintf(out, outlen, "%d.%d.%d.%d.in-addr.arpa",
+                        (int)(uint8_t)((a    )&0xff),
+                        (int)(uint8_t)((a>>8 )&0xff),
+                        (int)(uint8_t)((a>>16)&0xff),
+                        (int)(uint8_t)((a>>24)&0xff));
+  } else if (addr->family == AF_INET6) {
+    int i;
+    char *cp = out;
+    if (outlen < REVERSE_LOOKUP_NAME_BUF_LEN)
+      return -1;
+    for (i = 15; i >= 0; --i) {
+      uint8_t byte = addr->addr.in6_addr.s6_addr[i];
+      *cp++ = "0123456789abcdef"[byte & 0x0f];
+      *cp++ = '.';
+      *cp++ = "0123456789abcdef"[byte >> 4];
+      *cp++ = '.';
+    }
+    memcpy(cp, "ip6.arpa", 9); /* 8 characters plus nul */
+    return 0;
+  }
+  return -1;
+}
+
 /** Parse a string <b>s</b> containing an IPv4/IPv6 address, and possibly
  *  a mask and port or port range.  Store the parsed address in
  *  <b>addr_out</b>, a mask (if any) in <b>mask_out</b>, and port(s) (if any)
@@ -831,6 +964,13 @@ tor_dup_addr(const tor_addr_t *addr)
   return tor_strdup(buf);
 }
 
+/** Copy the address in <b>src</b> to <b>dest</b> */
+void
+tor_addr_assign(tor_addr_t *dest, const tor_addr_t *src)
+{
+  memcpy(dest, src, sizeof(tor_addr_t));
+}
+
 /** Return a string representing the address <b>addr</b>.  This string is
  * statically allocated, and must not be freed.  Each call to
  * <b>fmt_addr</b> invalidates the last result of the function.  This
diff --git a/src/common/address.h b/src/common/address.h
index 5f9e01910a..fa2ac1b5bc 100644
--- a/src/common/address.h
+++ b/src/common/address.h
@@ -90,6 +90,7 @@ tor_addr_eq_ipv4h(const tor_addr_t *a, uint32_t u)
 
 int tor_addr_lookup(const char *name, uint16_t family, tor_addr_t *addr_out);
 char *tor_dup_addr(const tor_addr_t *addr) ATTR_MALLOC;
+void tor_addr_assign(tor_addr_t *dest, const tor_addr_t *src);
 const char *fmt_addr(const tor_addr_t *addr);
 int get_interface_address6(int severity, sa_family_t family, tor_addr_t *addr);
 
@@ -113,6 +114,15 @@ int tor_addr_compare_masked(const tor_addr_t *addr1, const tor_addr_t *addr2,
 unsigned int tor_addr_hash(const tor_addr_t *addr);
 int tor_addr_is_v4(const tor_addr_t *addr);
 int tor_addr_is_internal(const tor_addr_t *ip, int for_listening) ATTR_PURE;
+
+/** Longest length that can be required for a reverse lookup name. */
+/* 32 nybbles, 32 dots, 8 characters of "ip6.arpa", 1 NUL: 73 characters. */
+#define REVERSE_LOOKUP_NAME_BUF_LEN 73
+int tor_addr_to_reverse_lookup_name(char *out, size_t outlen,
+                                    const tor_addr_t *addr);
+int tor_addr_parse_reverse_lookup_name(tor_addr_t *result, const char *address,
+                                       int family, int accept_regular);
+
 int tor_addr_port_parse(const char *s, tor_addr_t *addr_out,
                         uint16_t *port_out);
 int tor_addr_parse_mask_ports(const char *s,
diff --git a/src/or/connection_edge.c b/src/or/connection_edge.c
index 620db73a62..9b192b5565 100644
--- a/src/or/connection_edge.c
+++ b/src/or/connection_edge.c
@@ -1436,17 +1436,10 @@ connection_ap_handshake_rewrite_and_attach(edge_connection_t *conn,
     if (options->ClientDNSRejectInternalAddresses) {
       /* Don't let people try to do a reverse lookup on 10.0.0.1. */
       tor_addr_t addr;
-      struct in_addr in;
       int ok;
-      if (!strcasecmpend(socks->address, ".in-addr.arpa"))
-        ok = !parse_inaddr_arpa_address(socks->address, &in);
-      else
-        ok = tor_inet_aton(socks->address, &in);
-      /*XXXX021 make this a function. */
-      addr.family = AF_INET;
-      memcpy(&addr.addr.in_addr, &in, sizeof(struct in_addr));
-
-      if (ok && tor_addr_is_internal(&addr, 0)) {
+      ok = tor_addr_parse_reverse_lookup_name(
+                               &addr, socks->address, AF_UNSPEC, 1);
+      if (ok == 1 && tor_addr_is_internal(&addr, 0)) {
         connection_ap_handshake_socks_resolved(conn, RESOLVED_TYPE_ERROR,
                                                0, NULL, -1, TIME_MAX);
         connection_mark_unattached_ap(conn,
@@ -2130,7 +2123,7 @@ connection_ap_handshake_send_resolve(edge_connection_t *ap_conn)
 {
   int payload_len, command;
   const char *string_addr;
-  char inaddr_buf[32];
+  char inaddr_buf[REVERSE_LOOKUP_NAME_BUF_LEN];
   origin_circuit_t *circ;
   tor_assert(ap_conn->on_circuit);
   circ = TO_ORIGIN_CIRCUIT(ap_conn->on_circuit);
@@ -2155,36 +2148,29 @@ connection_ap_handshake_send_resolve(edge_connection_t *ap_conn)
     payload_len = (int)strlen(string_addr)+1;
     tor_assert(payload_len <= RELAY_PAYLOAD_SIZE);
   } else {
-    struct in_addr in;
-    uint32_t a;
-    size_t len = strlen(ap_conn->socks_request->address);
-    char c = 0;
-    /* XXXX This logic is a little ugly: we check for an in-addr.arpa ending
-     * on the address.  If we have one, the address is already in the right
-     * order, so we'll leave it alone later.  Otherwise, we reverse it and
-     * turn it into an in-addr.arpa address. */
-    if (!strcasecmpend(ap_conn->socks_request->address, ".in-addr.arpa")) {
-      /* Temporarily truncate the address, so we can give it to inet_aton. */
-      c = ap_conn->socks_request->address[len-13];
-      ap_conn->socks_request->address[len-13] = '\0';
-    }
-    if (tor_inet_aton(ap_conn->socks_request->address, &in) == 0) {
+    /* command == SOCKS_COMMAND_RESOLVE_PTR */
+    const char *a = ap_conn->socks_request->address;
+    tor_addr_t addr;
+    int r;
+
+    /* We're doing a reverse lookup.  The input could be an IP address, or
+     * could be an .in-addr.arpa or .ip6.arpa address */
+    r = tor_addr_parse_reverse_lookup_name(&addr, a, AF_INET, 1);
+    if (r <= 0) {
+      log_warn(LD_APP, "Rejecting ill-formed reverse lookup of %s",
+               safe_str(a));
       connection_mark_unattached_ap(ap_conn, END_STREAM_REASON_INTERNAL);
       return -1;
     }
-    if (c) {
-      /* this path happens on DNS. Can we unify? XXXX021 */
-      ap_conn->socks_request->address[len-13] = c;
-      strlcpy(inaddr_buf, ap_conn->socks_request->address, sizeof(inaddr_buf));
-    } else {
-      /* this path happens on tor-resolve. Can we unify? XXXX021 */
-      a = ntohl(in.s_addr);
-      tor_snprintf(inaddr_buf, sizeof(inaddr_buf), "%d.%d.%d.%d.in-addr.arpa",
-                   (int)(uint8_t)((a    )&0xff),
-                   (int)(uint8_t)((a>>8 )&0xff),
-                   (int)(uint8_t)((a>>16)&0xff),
-                   (int)(uint8_t)((a>>24)&0xff));
+
+    r = tor_addr_to_reverse_lookup_name(inaddr_buf, sizeof(inaddr_buf), &addr);
+    if (r < 0) {
+      log_warn(LD_BUG, "Couldn't generate reverse lookup hostname of %s",
+               safe_str(a));
+      connection_mark_unattached_ap(ap_conn, END_STREAM_REASON_INTERNAL);
+      return -1;
     }
+
     string_addr = inaddr_buf;
     payload_len = (int)strlen(inaddr_buf)+1;
     tor_assert(payload_len <= RELAY_PAYLOAD_SIZE);
diff --git a/src/or/dns.c b/src/or/dns.c
index a83c48981d..191fd068c1 100644
--- a/src/or/dns.c
+++ b/src/or/dns.c
@@ -494,49 +494,6 @@ send_resolved_hostname_cell(edge_connection_t *conn, const char *hostname)
   // log_notice(LD_EXIT, "Sent");
 }
 
-/** Given a lower-case <b>address</b>, check to see whether it's a
- * 1.2.3.4.in-addr.arpa address used for reverse lookups.  If so,
- * parse it and place the address in <b>in</b> if present. Return 1 on success;
- * 0 if the address is not in in-addr.arpa format, and -1 if the address is
- * malformed. */
-/* XXXX021 move this to address.c; unify with logic in connection_edge.c */
-int
-parse_inaddr_arpa_address(const char *address, struct in_addr *in)
-{
-  char buf[INET_NTOA_BUF_LEN];
-  char *cp;
-  size_t len;
-  struct in_addr inaddr;
-
-  cp = strstr(address, ".in-addr.arpa");
-  if (!cp || *(cp+strlen(".in-addr.arpa")))
-    return 0; /* not an .in-addr.arpa address  */
-
-  len = cp - address;
-
-  if (len >= INET_NTOA_BUF_LEN)
-    return -1; /* Too long. */
-
-  memcpy(buf, address, len);
-  buf[len] = '\0';
-  if (tor_inet_aton(buf, &inaddr) == 0)
-    return -1; /* malformed. */
-
-  if (in) {
-    uint32_t a;
-    /* reverse the bytes */
-    a = (uint32_t) (  ((inaddr.s_addr & 0x000000fful) << 24)
-                     |((inaddr.s_addr & 0x0000ff00ul) << 8)
-                     |((inaddr.s_addr & 0x00ff0000ul) >> 8)
-                     |((inaddr.s_addr & 0xff000000ul) >> 24));
-    inaddr.s_addr = a;
-
-    memcpy(in, &inaddr, sizeof(inaddr));
-  }
-
-  return 1;
-}
-
 /** See if we have a cache entry for <b>exitconn</b>-\>address. if so,
  * if resolve valid, put it into <b>exitconn</b>-\>addr and return 1.
  * If resolve failed, free exitconn and return -1.
@@ -646,7 +603,7 @@ dns_resolve_impl(edge_connection_t *exitconn, int is_resolve,
   cached_resolve_t search;
   pending_connection_t *pending_connection;
   routerinfo_t *me;
-  struct in_addr in;
+  tor_addr_t addr;
   time_t now = time(NULL);
   uint8_t is_reverse = 0;
   int r;
@@ -657,8 +614,8 @@ dns_resolve_impl(edge_connection_t *exitconn, int is_resolve,
 
   /* first check if exitconn->_base.address is an IP. If so, we already
    * know the answer. */
-  if (tor_inet_aton(exitconn->_base.address, &in) != 0) {
-    tor_addr_from_ipv4n(&exitconn->_base.addr, in.s_addr);
+  if (tor_addr_from_str(&addr, exitconn->_base.address)<0) {
+    tor_addr_assign(&exitconn->_base.addr, &addr);
     exitconn->address_ttl = DEFAULT_DNS_TTL;
     return 1;
   }
@@ -685,11 +642,12 @@ dns_resolve_impl(edge_connection_t *exitconn, int is_resolve,
    * .in-addr.arpa address but this isn't a resolve request, kill the
    * connection.
    */
-  if ((r = parse_inaddr_arpa_address(exitconn->_base.address, &in)) != 0) {
+  if ((r = tor_addr_parse_reverse_lookup_name(&addr, exitconn->_base.address,
+                                              AF_UNSPEC, 0)) != 0) {
     if (r == 1) {
       is_reverse = 1;
-         if (is_internal_IP(ntohl(in.s_addr), 0)) /* internal address */
-           return -1;
+      if (tor_addr_is_internal(&addr, 0)) /* internal address? */
+        return -1;
     }
 
     if (!is_reverse || !is_resolve) {
@@ -1298,7 +1256,7 @@ static int
 launch_resolve(edge_connection_t *exitconn)
 {
   char *addr = tor_strdup(exitconn->_base.address);
-  struct in_addr in;
+  tor_addr_t a;
   int r;
   int options = get_options()->ServerDNSSearchDomains ? 0
     : DNS_QUERY_NO_SEARCH;
@@ -1311,7 +1269,8 @@ launch_resolve(edge_connection_t *exitconn)
     }
   }
 
-  r = parse_inaddr_arpa_address(exitconn->_base.address, &in);
+  r = tor_addr_parse_reverse_lookup_name(
+                            &a, exitconn->_base.address, AF_UNSPEC, 0);
   if (r == 0) {
     log_info(LD_EXIT, "Launching eventdns request for %s",
              escaped_safe_str(exitconn->_base.address));
@@ -1320,8 +1279,12 @@ launch_resolve(edge_connection_t *exitconn)
   } else if (r == 1) {
     log_info(LD_EXIT, "Launching eventdns reverse request for %s",
              escaped_safe_str(exitconn->_base.address));
-    r = evdns_resolve_reverse(&in, DNS_QUERY_NO_SEARCH,
-                                 evdns_callback, addr);
+    if (tor_addr_family(&a) == AF_INET)
+      r = evdns_resolve_reverse(tor_addr_to_in(&a), DNS_QUERY_NO_SEARCH,
+                                evdns_callback, addr);
+    else
+      r = evdns_resolve_reverse_ipv6(tor_addr_to_in6(&a), DNS_QUERY_NO_SEARCH,
+                                     evdns_callback, addr);
   } else if (r == -1) {
     log_warn(LD_BUG, "Somehow a malformed in-addr.arpa address reached here.");
   }
diff --git a/src/or/eventdns.c b/src/or/eventdns.c
index 2b28b2bf94..cd486caaa1 100644
--- a/src/or/eventdns.c
+++ b/src/or/eventdns.c
@@ -2534,7 +2534,7 @@ int evdns_resolve_ipv6(const char *name, int flags,
 	}
 }
 
-int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
+int evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
 	char buf[32];
 	struct request *req;
 	u32 a;
@@ -2552,7 +2552,7 @@ int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type cal
 	return 0;
 }
 
-int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
+int evdns_resolve_reverse_ipv6(const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
 	/* 32 nybbles, 32 periods, "ip6.arpa", NUL. */
 	char buf[73];
 	char *cp;
diff --git a/src/or/eventdns.h b/src/or/eventdns.h
index d1c34ade7c..df5b936923 100644
--- a/src/or/eventdns.h
+++ b/src/or/eventdns.h
@@ -268,8 +268,8 @@ int evdns_resolve_ipv4(const char *name, int flags, evdns_callback_type callback
 int evdns_resolve_ipv6(const char *name, int flags, evdns_callback_type callback, void *ptr);
 struct in_addr;
 struct in6_addr;
-int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
-int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
+int evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
+int evdns_resolve_reverse_ipv6(const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
 int evdns_set_option(const char *option, const char *val, int flags);
 int evdns_resolv_conf_parse(int flags, const char *);
 #ifdef MS_WINDOWS
diff --git a/src/or/or.h b/src/or/or.h
index b766083f44..9093127ee3 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -3541,7 +3541,6 @@ int dns_resolve(edge_connection_t *exitconn);
 void dns_launch_correctness_checks(void);
 int dns_seems_to_be_broken(void);
 void dns_reset_correctness_checks(void);
-int parse_inaddr_arpa_address(const char *address, struct in_addr *in);
 
 /********************************* dnsserv.c ************************/
 
diff --git a/src/or/test.c b/src/or/test.c
index 8b07ee536a..28bf46f952 100644
--- a/src/or/test.c
+++ b/src/or/test.c
@@ -1621,6 +1621,70 @@ test_util_ip6_helpers(void)
   p1 = tor_addr_to_str(buf, &t1, sizeof(buf), 1);
   test_streq(p1, "18.0.0.1");
 
+  /* Test tor_addr_parse_reverse_lookup_name */
+  i = tor_addr_parse_reverse_lookup_name(&t1, "Foobar.baz", AF_UNSPEC, 0);
+  test_eq(0, i);
+  i = tor_addr_parse_reverse_lookup_name(&t1, "Foobar.baz", AF_UNSPEC, 1);
+  test_eq(0, i);
+  i = tor_addr_parse_reverse_lookup_name(&t1, "1.0.168.192.in-addr.arpa",
+                                         AF_UNSPEC, 1);
+  test_eq(1, i);
+  test_eq(tor_addr_family(&t1), AF_INET);
+  p1 = tor_addr_to_str(buf, &t1, sizeof(buf), 1);
+  test_streq(p1, "192.168.0.1");
+  i = tor_addr_parse_reverse_lookup_name(&t1, "192.168.0.99", AF_UNSPEC, 0);
+  test_eq(0, i);
+  i = tor_addr_parse_reverse_lookup_name(&t1, "192.168.0.99", AF_UNSPEC, 1);
+  test_eq(1, i);
+  p1 = tor_addr_to_str(buf, &t1, sizeof(buf), 1);
+  test_streq(p1, "192.168.0.99");
+  memset(&t1, 0, sizeof(t1));
+  i = tor_addr_parse_reverse_lookup_name(&t1,
+                                         "0.1.2.3.4.5.6.7.8.9.a.b.c.d.e.f."
+                                         "f.e.e.b.1.e.b.e.e.f.f.e.e.e.d.9."
+                                         "ip6.ARPA",
+                                         AF_UNSPEC, 0);
+  test_eq(1, i);
+  p1 = tor_addr_to_str(buf, &t1, sizeof(buf), 1);
+  test_streq(p1, "[9dee:effe:ebe1:beef:fedc:ba98:7654:3210]");
+  /* Failing cases. */
+  i = tor_addr_parse_reverse_lookup_name(&t1,
+                                         "6.7.8.9.a.b.c.d.e.f."
+                                         "f.e.e.b.1.e.b.e.e.f.f.e.e.e.d.9."
+                                         "ip6.ARPA",
+                                         AF_UNSPEC, 0);
+  test_eq(i, -1);
+  i = tor_addr_parse_reverse_lookup_name(&t1,
+                                         "6.7.8.9.a.b.c.d.e.f.a.b.c.d.e.f.0."
+                                         "f.e.e.b.1.e.b.e.e.f.f.e.e.e.d.9."
+                                         "ip6.ARPA",
+                                         AF_UNSPEC, 0);
+  test_eq(i, -1);
+  i = tor_addr_parse_reverse_lookup_name(&t1,
+                                         "6.7.8.9.a.b.c.d.e.f.X.0.0.0.0.9."
+                                         "f.e.e.b.1.e.b.e.e.f.f.e.e.e.d.9."
+                                         "ip6.ARPA",
+                                         AF_UNSPEC, 0);
+  test_eq(i, -1);
+  i = tor_addr_parse_reverse_lookup_name(&t1, "32.1.1.in-addr.arpa",
+                                         AF_UNSPEC, 0);
+  /* test_eq(i, -1); XXXX021 Apparently '32.1.1' is a valid aton address. */
+  i = tor_addr_parse_reverse_lookup_name(&t1, ".in-addr.arpa",
+                                         AF_UNSPEC, 0);
+  test_eq(i, -1);
+  i = tor_addr_parse_reverse_lookup_name(&t1, "1.2.3.4.5.in-addr.arpa",
+                                         AF_UNSPEC, 0);
+  test_eq(i, -1);
+  i = tor_addr_parse_reverse_lookup_name(&t1, "1.2.3.4.5.in-addr.arpa",
+                                         AF_INET6, 0);
+  test_eq(i, -1);
+  i = tor_addr_parse_reverse_lookup_name(&t1,
+                                         "6.7.8.9.a.b.c.d.e.f.a.b.c.d.e.0."
+                                         "f.e.e.b.1.e.b.e.e.f.f.e.e.e.d.9."
+                                         "ip6.ARPA",
+                                         AF_INET, 0);
+  test_eq(i, -1);
+
   /* test tor_addr_parse_mask_ports */
   test_addr_mask_ports_parse("[::f]/17:47-95", AF_INET6,
                              0, 0, 0, 0x0000000f, 17, 47, 95);