ejabberd_router、ejabberd_router_multicast

ejabberd_router作为gen_server启动,作为系统的路由

对外提供注册路由、删除路由

初始化时创建route（mnesia）表，监控注册的路由进程

主要方法为do_route(OrigFrom, OrigTo, OrigPacket)方法

do_route(OrigFrom, OrigTo, OrigPacket) ->
    ?DEBUG("route~n\tfrom ~p~n\tto ~p~n\tpacket "
       "~p~n",
       [OrigFrom, OrigTo, OrigPacket]),
    case ejabberd_hooks:run_fold(filter_packet,
                 {OrigFrom, OrigTo, OrigPacket}, [])
    of
      {From, To, Packet} ->
      LDstDomain = To#jid.lserver,
      case mnesia:dirty_read(route, LDstDomain) of
        [] -> ejabberd_s2s:route(From, To, Packet);
        [R] ->
        Pid = R#route.pid,
        if node(Pid) == node() ->
               case R#route.local_hint of
             {apply, Module, Function} ->
                 Module:Function(From, To, Packet);
             _ -> Pid ! {route, From, To, Packet}
               end;
           is_pid(Pid) -> Pid ! {route, From, To, Packet};
           true -> drop
        end;
        Rs ->
        Value = case
              ejabberd_config:get_local_option({domain_balancing,
                                LDstDomain}, fun(D) when is_atom(D) -> D end)
                of
              undefined -> now();
              random -> now();
              source -> jid:tolower(From);
              destination -> jid:tolower(To);
              bare_source ->
                  jid:remove_resource(jid:tolower(From));
              bare_destination ->
                  jid:remove_resource(jid:tolower(To))
            end,
        case get_component_number(LDstDomain) of
          undefined ->
              case [R || R <- Rs, node(R#route.pid) == node()] of
            [] ->
                R = lists:nth(erlang:phash(Value, length(Rs)), Rs),
                Pid = R#route.pid,
                if is_pid(Pid) -> Pid ! {route, From, To, Packet};
                   true -> drop
                end;
            LRs ->
                R = lists:nth(erlang:phash(Value, length(LRs)),
                      LRs),
                Pid = R#route.pid,
                case R#route.local_hint of
                  {apply, Module, Function} ->
                  Module:Function(From, To, Packet);
                  _ -> Pid ! {route, From, To, Packet}
                end
              end;
          _ ->
              SRs = lists:ukeysort(#route.local_hint, Rs),
              R = lists:nth(erlang:phash(Value, length(SRs)), SRs),
              Pid = R#route.pid,
              if is_pid(Pid) -> Pid ! {route, From, To, Packet};
             true -> drop
              end
        end
      end;
      drop -> ok
    end.

在route表里面查找要发送域的路由信息，如果没有找到则利用ejabberd_s2s发送到别的节点查找，如果找到则：

调用进程注册的函数

-module(ejabberd_local).
ejabberd_router:register_route(Host,
                             {apply, ?MODULE,
                              route}),

或者直接发送信息到注册的进程

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ejabberd_router_multicast作为gen_server启动，多播路由

对外提供注册删除路由

主要为do_route(From, Domain, Destinations, Packet)方法

首先到route_multicast（mnesia）表里面查找

若果找到则直接往注册的进程pid里面发送信息Pid ! {route_trusted, From, Destinations, Packet}

否则走普通的路由

do_route_normal(From, Destinations, Packet) ->
    [ejabberd_router:route(From, To, Packet) || To <- Destinations].