HttpControlMsg.h

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/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
#ifndef SQUID_HTTP_CONTROL_MSG_H
#define SQUID_HTTP_CONTROL_MSG_H
 
#include "base/AsyncCall.h"
#include "HttpReply.h"
 
class CommIoCbParams;
class HttpControlMsg;
 
/*
 * This API exists to throttle forwarding of 1xx messages from the server
 * side (Source == HttpStateData) to the client side (Sink == ConnStateData).
 *
 * Without throttling, Squid would have to drop some 1xx responses to
 * avoid DoS attacks that send many 1xx responses without reading them.
 * Dropping 1xx responses without violating HTTP is as complex as throttling.
 */
 
class HttpControlMsgSink: public virtual AsyncJob
{
public:
    HttpControlMsgSink(): AsyncJob("unused") {}
 
    virtual void sendControlMsg(HttpControlMsg msg) = 0;
 
    virtual void doneWithControlMsg();
 
    void wroteControlMsg(const CommIoCbParams &);
 
    AsyncCall::Pointer cbControlMsgSent;
};
 
class HttpControlMsg
{
public:
    typedef AsyncCall::Pointer Callback;
 
    HttpControlMsg(const HttpReply::Pointer &aReply, const Callback &aCallback):
        reply(aReply), cbSuccess(aCallback) {}
 
public:
    HttpReply::Pointer reply; 
    Callback cbSuccess; 
 
    // We could add an API to notify of send failures as well, but the
    // current Source and Sink are tied via Store anyway, so the Source
    // will know, eventually, if the Sink is gone or otherwise failed.
};
 
inline std::ostream &
operator <<(std::ostream &os, const HttpControlMsg &msg)
{
    return os << msg.reply << ", " << msg.cbSuccess;
}
 
#endif /* SQUID_HTTP_CONTROL_MSG_H */