From 7c8c096a729dc3489172eca45f931902c1563b4e Mon Sep 17 00:00:00 2001
From: Pavel Abalihin <abalihin@selectel.ru>
Date: Wed, 20 Aug 2014 13:01:36 +0400
Subject: [PATCH] IPv6 support

---
 include/emysql.hrl  |  5 ++++-
 src/emysql_conn.erl | 18 +++++++++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/include/emysql.hrl b/include/emysql.hrl
index 1320289f..c50a8b78 100644
--- a/include/emysql.hrl
+++ b/include/emysql.hrl
@@ -125,7 +125,10 @@
 -define(CONNECT_WITH_DB, 8).
 -define(CONN_TEST_PERIOD, 28000).
 -define(TCP_RECV_BUFFER, 8192).
-
+-define(SOCKET_OPTIONS, [binary,
+                         {packet, raw},
+                         {active, false},
+                         {recbuf, ?TCP_RECV_BUFFER}]).
 
 %% MYSQL TYPES
 -define(FIELD_TYPE_DECIMAL, 16#00).
diff --git a/src/emysql_conn.erl b/src/emysql_conn.erl
index 01a5c74b..edf7626f 100644
--- a/src/emysql_conn.erl
+++ b/src/emysql_conn.erl
@@ -187,7 +187,8 @@ open_connection(#pool{pool_id=PoolId, host=Host, port=Port, user=User,
                       start_cmds=StartCmds, connect_timeout=ConnectTimeout} = Pool) ->
      %-% io:format("~p open connection for pool ~p host ~p port ~p user ~p base ~p~n", [self(), PoolId, Host, Port, User, Database]),
      %-% io:format("~p open connection: ... connect ... ~n", [self()]),
-    case gen_tcp:connect(Host, Port, [binary, {packet, raw}, {active, false}, {recbuf, ?TCP_RECV_BUFFER}], ConnectTimeout) of
+    IpFamily = host_ipfamily(Host),
+    case gen_tcp:connect(Host, Port, [IpFamily | ?SOCKET_OPTIONS], ConnectTimeout) of
         {ok, Sock} ->
             #greeting {
                server_version = Version,
@@ -220,6 +221,21 @@ open_connection(#pool{pool_id=PoolId, host=Host, port=Port, user=User,
             exit({failed_to_connect_to_database, Reason})
     end.
 
+host_ipfamily(Host) ->
+    case inet_parse:address(Host) of
+        {ok, {_, _, _, _, _, _, _, _}} -> inet6;
+        {ok, {_, _, _, _}}             -> inet;
+        _ ->
+            case inet:getaddr(Host, inet6) of
+                {ok, _} -> inet6;
+                _ ->
+                    case inet:getaddr(Host, inet) of
+                        {ok, _}         -> inet;
+                        {error, Reason} -> exit(Reason)
+                    end
+            end
+    end.
+
 handshake(Sock, User, Password) ->
    case emysql_auth:handshake(Sock, User, Password) of
        {ok, #greeting{} = G} -> G;