src/HttpControlMsg.h

   1 #ifndef SQUID_HTTP_CONTROL_MSG_H
   2 #define SQUID_HTTP_CONTROL_MSG_H
   3
   4 #include "HttpReply.h"
   5 #include "base/AsyncCall.h"
   6
   7 class HttpControlMsg;
   8
   9 /*
  10  * This API exists to throttle forwarding of 1xx messages from the server
  11  * side (Source == HttpStateData) to the client side (Sink == ConnStateData).
  12  *
  13  * Without throttling, Squid would have to drop some 1xx responses to
  14  * avoid DoS attacks that send many 1xx responses without reading them.
  15  * Dropping 1xx responses without violating HTTP is as complex as throttling.
  16  */
  17
  18 /// sends a single control message, notifying the Sink
  19 class HttpControlMsgSink: public virtual AsyncJob
  20 {
  21 public:
  22     HttpControlMsgSink(): AsyncJob("unused") {}
  23
  24     /// called to send the 1xx message and notify the Source
  25     virtual void sendControlMsg(HttpControlMsg msg) = 0;
  26 };
  27
  28 /// bundles HTTP 1xx reply and the "successfully forwarded" callback
  29 class HttpControlMsg
  30 {
  31 public:
  32     typedef HttpMsgPointerT<HttpReply> MsgPtr;
  33     typedef AsyncCall::Pointer Callback;
  34
  35     HttpControlMsg(const MsgPtr &aReply, const Callback &aCallback):
  36             reply(aReply), cbSuccess(aCallback) {}
  37
  38 public:
  39     MsgPtr reply; ///< the 1xx message being forwarded
  40     Callback cbSuccess; ///< called after successfully writing the 1xx message
  41
  42     // We could add an API to notify of send failures as well, but the
  43     // current Source and Sink are tied via Store anyway, so the Source
  44     // will know, eventually, if the Sink is gone or otherwise failed.
  45 };
  46
  47 inline std::ostream &
  48 operator <<(std::ostream &os, const HttpControlMsg &msg)
  49 {
  50     return os << msg.reply << ", " << msg.cbSuccess;
  51 }
  52
  53 #endif /* SQUID_HTTP_CONTROL_MSG_H */