From da268e3b508fb5f9ab3b930deded331c387f7243 Mon Sep 17 00:00:00 2001
From: Neel Chauhan <neel@neelc.org>
Date: Tue, 31 Jul 2018 08:17:59 -0400
Subject: [PATCH] Add function fascist_firewall_choose_address_ls()

---
 src/core/or/policies.c | 55 ++++++++++++++++++++++++++++++++++++++++++
 src/core/or/policies.h |  3 +++
 2 files changed, 58 insertions(+)

diff --git a/src/core/or/policies.c b/src/core/or/policies.c
index f59894ea8f..26a053821a 100644
--- a/src/core/or/policies.c
+++ b/src/core/or/policies.c
@@ -31,6 +31,7 @@
 #include "ht.h"
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/encoding/confline.h"
+#include "trunnel/ed25519_cert.h"
 
 #include "core/or/addr_policy_st.h"
 #include "feature/dirclient/dir_server_st.h"
@@ -1015,6 +1016,60 @@ fascist_firewall_choose_address_rs(const routerstatus_t *rs,
   }
 }
 
+/** Like fascist_firewall_choose_address_base(), but takes in a smartlist
+ * <b>lspecs</b> consisting of one or more link specifiers.
+ */
+void
+fascist_firewall_choose_address_ls(const smartlist_t *lspecs,
+                                   int pref_only, tor_addr_port_t* ap,
+                                   int direct_conn)
+{
+  int have_v4 = 0, have_v6 = 0;
+  uint16_t port_v4 = 0, port_v6 = 0;
+  tor_addr_t addr_v4, addr_v6;
+
+  SMARTLIST_FOREACH_BEGIN(lspecs, const link_specifier_t *, ls) {
+    switch (link_specifier_get_ls_type(ls)) {
+    case LS_IPV4:
+      /* Skip if we already seen a v4. */
+      if (have_v4) continue;
+      tor_addr_from_ipv4h(&addr_v4,
+                          link_specifier_get_un_ipv4_addr(ls));
+      port_v4 = link_specifier_get_un_ipv4_port(ls);
+      have_v4 = 1;
+      break;
+    case LS_IPV6:
+      /* Skip if we already seen a v6, or deliberately skip it if we're not a
+       * direct connection. */
+      if (have_v6 || !direct_conn) continue;
+      tor_addr_from_ipv6_bytes(&addr_v6,
+          (const char *) link_specifier_getconstarray_un_ipv6_addr(ls));
+      port_v6 = link_specifier_get_un_ipv6_port(ls);
+      have_v6 = 1;
+      break;
+    default:
+      /* Ignore unknown. */
+      break;
+    }
+  } SMARTLIST_FOREACH_END(ls);
+
+  tor_assert(ap);
+
+  tor_addr_make_null(&ap->addr, AF_UNSPEC);
+  ap->port = 0;
+
+  /* Here, don't check for DirPorts as link specifiers are only used for
+   * ORPorts. */
+  const or_options_t *options = get_options();
+  int pref_ipv6 = fascist_firewall_prefer_ipv6_orport(options);
+  /* Assume that the DirPorts are zero as link specifiers only use ORPorts. */
+  fascist_firewall_choose_address_base(&addr_v4, port_v4, 0,
+                                       &addr_v6, port_v6, 0,
+                                       FIREWALL_OR_CONNECTION,
+                                       pref_only, pref_ipv6,
+                                       ap);
+}
+
 /** Like fascist_firewall_choose_address_base(), but takes <b>node</b>, and
  * looks up the node's IPv6 preference rather than taking an argument
  * for pref_ipv6. */
diff --git a/src/core/or/policies.h b/src/core/or/policies.h
index 324c1c2dd1..f4c68fd952 100644
--- a/src/core/or/policies.h
+++ b/src/core/or/policies.h
@@ -92,6 +92,9 @@ int fascist_firewall_allows_dir_server(const dir_server_t *ds,
 void fascist_firewall_choose_address_rs(const routerstatus_t *rs,
                                         firewall_connection_t fw_connection,
                                         int pref_only, tor_addr_port_t* ap);
+void fascist_firewall_choose_address_ls(const smartlist_t *lspecs,
+                                        int pref_only, tor_addr_port_t* ap,
+                                        int direct_conn);
 void fascist_firewall_choose_address_node(const node_t *node,
                                           firewall_connection_t fw_connection,
                                           int pref_only, tor_addr_port_t* ap);