/*
 * Copyright (C) 1996-2021 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.
 */

/* DEBUG: section 33    Client-side Routines */

#ifndef SQUID_CLIENTSIDE_H
#define SQUID_CLIENTSIDE_H

#include "base/RunnersRegistry.h"
#include "clientStreamForward.h"
#include "comm.h"
#include "helper/forward.h"
#include "http/forward.h"
#include "HttpControlMsg.h"
#include "ipc/FdNotes.h"
#include "sbuf/SBuf.h"
#include "servers/Server.h"
#if USE_AUTH
#include "auth/UserRequest.h"
#endif
#if USE_OPENSSL
#include "security/Handshake.h"
#include "ssl/support.h"
#endif

#include <iosfwd>

class ClientHttpRequest;
class HttpHdrRangeSpec;

class MasterXaction;
typedef RefCount<MasterXaction> MasterXactionPointer;

#if USE_OPENSSL
namespace Ssl
{
class ServerBump;
}
#endif

/**
 * Legacy Server code managing a connection to a client.
 *
 * NP: presents AsyncJob API but does not operate autonomously as a Job.
 *     So Must() is not safe to use.
 *
 * Multiple requests (up to pipeline_prefetch) can be pipelined.
 * This object is responsible for managing which one is currently being
 * fulfilled and what happens to the queue if the current one causes the client
 * connection to be closed early.
 *
 * Act as a manager for the client connection and passes data in buffer to a
 * Parser relevant to the state (message headers vs body) that is being
 * processed.
 *
 * Performs HTTP message processing to kick off the actual HTTP request
 * handling objects (Http::Stream, ClientHttpRequest, HttpRequest).
 *
 * Performs SSL-Bump processing for switching between HTTP and HTTPS protocols.
 *
 * To terminate a ConnStateData close() the client Comm::Connection it is
 * managing, or for graceful half-close use the stopReceiving() or
 * stopSending() methods.
 */
class ConnStateData : public Server, public HttpControlMsgSink, private IndependentRunner
{

public:
    explicit ConnStateData(const MasterXactionPointer &xact);
    virtual ~ConnStateData();

    /* ::Server API */
    virtual void receivedFirstByte();
    virtual bool handleReadData();
    virtual void afterClientRead();
    virtual void afterClientWrite(size_t);

    /* HttpControlMsgSink API */
    virtual void sendControlMsg(HttpControlMsg);
    virtual void doneWithControlMsg();

    /// Traffic parsing
    bool clientParseRequests();
    void readNextRequest();

    /// try to make progress on a transaction or read more I/O
    void kick();

    bool isOpen() const;

    Http1::TeChunkedParser *bodyParser; ///< parses HTTP/1.1 chunked request body

    /** number of body bytes we need to comm_read for the "current" request
     *
     * \retval 0         We do not need to read any [more] body bytes
     * \retval negative  May need more but do not know how many; could be zero!
     * \retval positive  Need to read exactly that many more body bytes
     */
    int64_t mayNeedToReadMoreBody() const;

#if USE_AUTH
    /**
     * Fetch the user details for connection based authentication
     * NOTE: this is ONLY connection based because NTLM and Negotiate is against HTTP spec.
     */
    const Auth::UserRequest::Pointer &getAuth() const { return auth_; }

    /**
     * Set the user details for connection-based authentication to use from now until connection closure.
     *
     * Any change to existing credentials shows that something invalid has happened. Such as:
     * - NTLM/Negotiate auth was violated by the per-request headers missing a revalidation token
     * - NTLM/Negotiate auth was violated by the per-request headers being for another user
     * - SSL-Bump CONNECT tunnel with persistent credentials has ended
     */
    void setAuth(const Auth::UserRequest::Pointer &aur, const char *cause);
#endif

    Ip::Address log_addr;

    struct {
        bool readMore; ///< needs comm_read (for this request or new requests)
        bool swanSang; // XXX: temporary flag to check proper cleanup
    } flags;
    struct {
        Comm::ConnectionPointer serverConnection; /* pinned server side connection */
        char *host;             /* host name of pinned connection */
        int port;               /* port of pinned connection */
        bool pinned;             /* this connection was pinned */
        bool auth;               /* pinned for www authentication */
        bool reading;   ///< we are monitoring for peer connection closure
        bool zeroReply; ///< server closed w/o response (ERR_ZERO_SIZE_OBJECT)
        CachePeer *peer;             /* CachePeer the connection goes via */
        AsyncCall::Pointer readHandler; ///< detects serverConnection closure
        AsyncCall::Pointer closeHandler; /*The close handler for pinned server side connection*/
    } pinning;

    bool transparent() const;

    /// true if we stopped receiving the request
    const char *stoppedReceiving() const { return stoppedReceiving_; }
    /// true if we stopped sending the response
    const char *stoppedSending() const { return stoppedSending_; }
    /// note request receiving error and close as soon as we write the response
    void stopReceiving(const char *error);
    /// note response sending error and close as soon as we read the request
    void stopSending(const char *error);

    void expectNoForwarding(); ///< cleans up virgin request [body] forwarding state

    /* BodyPipe API */
    BodyPipe::Pointer expectRequestBody(int64_t size);
    virtual void noteMoreBodySpaceAvailable(BodyPipe::Pointer) = 0;
    virtual void noteBodyConsumerAborted(BodyPipe::Pointer) = 0;

    bool handleRequestBodyData();

    /// parameters for the async notePinnedConnectionBecameIdle() call
    class PinnedIdleContext
    {
    public:
        PinnedIdleContext(const Comm::ConnectionPointer &conn, const HttpRequest::Pointer &req): connection(conn), request(req) {}

        Comm::ConnectionPointer connection; ///< to-server connection to be pinned
        HttpRequest::Pointer request; ///< to-server request that initiated serverConnection
    };

    /// Called when a pinned connection becomes available for forwarding the next request.
    void notePinnedConnectionBecameIdle(PinnedIdleContext pic);
    /// Forward future client requests using the given to-server connection.
    /// The connection is still being used by the current client request.
    void pinBusyConnection(const Comm::ConnectionPointer &pinServerConn, const HttpRequest::Pointer &request);
    /// Undo pinConnection() and, optionally, close the pinned connection.
    void unpinConnection(const bool andClose);
    /// Returns validated pinnned server connection (and stops its monitoring).
    Comm::ConnectionPointer borrowPinnedConnection(HttpRequest *request, const CachePeer *aPeer);
    /**
     * Checks if there is pinning info if it is valid. It can close the server side connection
     * if pinned info is not valid.
     \param request   if it is not NULL also checks if the pinning info refers to the request client side HttpRequest
     \param CachePeer      if it is not NULL also check if the CachePeer is the pinning CachePeer
     \return          The details of the server side connection (may be closed if failures were present).
     */
    const Comm::ConnectionPointer validatePinnedConnection(HttpRequest *request, const CachePeer *peer);
    /**
     * returts the pinned CachePeer if exists, NULL otherwise
     */
    CachePeer *pinnedPeer() const {return pinning.peer;}
    bool pinnedAuth() const {return pinning.auth;}

    /// called just before a FwdState-dispatched job starts using connection
    virtual void notePeerConnection(Comm::ConnectionPointer) {}

    // pining related comm callbacks
    virtual void clientPinnedConnectionClosed(const CommCloseCbParams &io);

    // comm callbacks
    void clientReadFtpData(const CommIoCbParams &io);
    void connStateClosed(const CommCloseCbParams &io);
    void requestTimeout(const CommTimeoutCbParams &params);

    // AsyncJob API
    virtual void start();
    virtual bool doneAll() const { return BodyProducer::doneAll() && false;}
    virtual void swanSong();

    /// Changes state so that we close the connection and quit after serving
    /// the client-side-detected error response instead of getting stuck.
    void quitAfterError(HttpRequest *request); // meant to be private

    /// The caller assumes responsibility for connection closure detection.
    void stopPinnedConnectionMonitoring();

    /// the second part of old httpsAccept, waiting for future HttpsServer home
    void postHttpsAccept();

#if USE_OPENSSL
    /// Initializes and starts a peek-and-splice negotiation with the SSL client
    void startPeekAndSplice();

    /// Called when a peek-and-splice step finished. For example after
    /// server SSL certificates received and fake server SSL certificates
    /// generated
    void doPeekAndSpliceStep();
    /// called by FwdState when it is done bumping the server
    void httpsPeeked(PinnedIdleContext pic);

    /// Splice a bumped client connection on peek-and-splice mode
    bool splice();

    /// Start to create dynamic Security::ContextPointer for host or uses static port SSL context.
    void getSslContextStart();

    /// finish configuring the newly created SSL context"
    void getSslContextDone(Security::ContextPointer &);

    /// Callback function. It is called when squid receive message from ssl_crtd.
    static void sslCrtdHandleReplyWrapper(void *data, const Helper::Reply &reply);
    /// Proccess response from ssl_crtd.
    void sslCrtdHandleReply(const Helper::Reply &reply);

    void switchToHttps(HttpRequest *request, Ssl::BumpMode bumpServerMode);
    void parseTlsHandshake();
    bool switchedToHttps() const { return switchedToHttps_; }
    Ssl::ServerBump *serverBump() {return sslServerBump;}
    inline void setServerBump(Ssl::ServerBump *srvBump) {
        if (!sslServerBump)
            sslServerBump = srvBump;
        else
            assert(sslServerBump == srvBump);
    }
    const SBuf &sslCommonName() const {return sslCommonName_;}
    void resetSslCommonName(const char *name) {sslCommonName_ = name;}
    const SBuf &tlsClientSni() const { return tlsClientSni_; }
    /// Fill the certAdaptParams with the required data for certificate adaptation
    /// and create the key for storing/retrieve the certificate to/from the cache
    void buildSslCertGenerationParams(Ssl::CertificateProperties &certProperties);
    /// Called when the client sends the first request on a bumped connection.
    /// Returns false if no [delayed] error should be written to the client.
    /// Otherwise, writes the error to the client and returns true. Also checks
    /// for SQUID_X509_V_ERR_DOMAIN_MISMATCH on bumped requests.
    bool serveDelayedError(Http::Stream *);

    Ssl::BumpMode sslBumpMode; ///< ssl_bump decision (Ssl::bumpEnd if n/a).

    /// Tls parser to use for client HELLO messages parsing on bumped
    /// connections.
    Security::HandshakeParser tlsParser;
#else
    bool switchedToHttps() const { return false; }
#endif
    char *prepareTlsSwitchingURL(const Http1::RequestParserPointer &hp);

    /* clt_conn_tag=tag annotation access */
    const SBuf &connectionTag() const { return connectionTag_; }
    void connectionTag(const char *aTag) { connectionTag_ = aTag; }

    /// handle a control message received by context from a peer and call back
    virtual bool writeControlMsgAndCall(HttpReply *rep, AsyncCall::Pointer &call) = 0;

    /// ClientStream calls this to supply response header (once) and data
    /// for the current Http::Stream.
    virtual void handleReply(HttpReply *header, StoreIOBuffer receivedData) = 0;

    /// remove no longer needed leading bytes from the input buffer
    void consumeInput(const size_t byteCount);

    /* TODO: Make the methods below (at least) non-public when possible. */

    /// stop parsing the request and create context for relaying error info
    Http::Stream *abortRequestParsing(const char *const errUri);

    /// generate a fake CONNECT request with the given payload
    /// at the beginning of the client I/O buffer
    bool fakeAConnectRequest(const char *reason, const SBuf &payload);

    /// generates and sends to tunnel.cc a fake request with a given payload
    bool initiateTunneledRequest(HttpRequest::Pointer const &cause, Http::MethodType const method, const char *reason, const SBuf &payload);

    /// whether we should start saving inBuf client bytes in anticipation of
    /// tunneling them to the server later (on_unsupported_protocol)
    bool shouldPreserveClientData() const;

    // TODO: move to the protected section when removing clientTunnelOnError()
    bool tunnelOnError(const HttpRequestMethod &, const err_type);

    /// build a fake http request
    ClientHttpRequest *buildFakeRequest(Http::MethodType const method, SBuf &useHost, unsigned short usePort, const SBuf &payload);

    /// From-client handshake bytes (including bytes at the beginning of a
    /// CONNECT tunnel) which we may need to forward as-is if their syntax does
    /// not match the expected TLS or HTTP protocol (on_unsupported_protocol).
    SBuf preservedClientData;

    /* Registered Runner API */
    virtual void startShutdown();
    virtual void endingShutdown();

protected:
    void startDechunkingRequest();
    void finishDechunkingRequest(bool withSuccess);
    void abortChunkedRequestBody(const err_type error);
    err_type handleChunkedRequestBody();

    void startPinnedConnectionMonitoring();
    void clientPinnedConnectionRead(const CommIoCbParams &io);
#if USE_OPENSSL
    /// Handles a ready-for-reading TLS squid-to-server connection that
    /// we thought was idle.
    /// \return false if and only if the connection should be closed.
    bool handleIdleClientPinnedTlsRead();
#endif

    /// Parse an HTTP request
    /// \note Sets result->flags.parsed_ok to 0 if failed to parse the request,
    ///       to 1 if the request was correctly parsed
    /// \param[in] hp an Http1::RequestParser
    /// \return NULL on incomplete requests,
    ///         a Http::Stream on success or failure.
    /// TODO: Move to HttpServer. Warning: Move requires large code nonchanges!
    Http::Stream *parseHttpRequest(const Http1::RequestParserPointer &);

    /// parse input buffer prefix into a single transfer protocol request
    /// return NULL to request more header bytes (after checking any limits)
    /// use abortRequestParsing() to handle parsing errors w/o creating request
    virtual Http::Stream *parseOneRequest() = 0;

    /// start processing a freshly parsed request
    virtual void processParsedRequest(Http::StreamPointer &) = 0;

    /// returning N allows a pipeline of 1+N requests (see pipeline_prefetch)
    virtual int pipelinePrefetchMax() const;

    /// timeout to use when waiting for the next request
    virtual time_t idleTimeout() const = 0;

    /// Perform client data lookups that depend on client src-IP.
    /// The PROXY protocol may require some data input first.
    void whenClientIpKnown();

    BodyPipe::Pointer bodyPipe; ///< set when we are reading request body

    /// whether preservedClientData is valid and should be kept up to date
    bool preservingClientData_;

private:
    /* ::Server API */
    virtual bool connFinishedWithConn(int size);
    virtual void checkLogging();

    void clientAfterReadingRequests();
    bool concurrentRequestQueueFilled() const;

    void pinConnection(const Comm::ConnectionPointer &pinServerConn, const HttpRequest &request);

    /* PROXY protocol functionality */
    bool proxyProtocolValidateClient();
    bool parseProxyProtocolHeader();
    bool parseProxy1p0();
    bool parseProxy2p0();
    bool proxyProtocolError(const char *reason);

#if USE_OPENSSL
    /// \returns a pointer to the matching cached TLS context or nil
    Security::ContextPointer getTlsContextFromCache(const SBuf &cacheKey, const Ssl::CertificateProperties &certProperties);

    /// Attempts to add a given TLS context to the cache, replacing the old
    /// same-key context, if any
    void storeTlsContextToCache(const SBuf &cacheKey, Security::ContextPointer &ctx);
#endif

    /// whether PROXY protocol header is still expected
    bool needProxyProtocolHeader_;

#if USE_AUTH
    /// some user details that can be used to perform authentication on this connection
    Auth::UserRequest::Pointer auth_;
#endif

#if USE_OPENSSL
    bool switchedToHttps_;
    bool parsingTlsHandshake; ///< whether we are getting/parsing TLS Hello bytes
    /// The number of parsed HTTP requests headers on a bumped client connection
    uint64_t parsedBumpedRequestCount;

    /// The TLS server host name appears in CONNECT request or the server ip address for the intercepted requests
    SBuf tlsConnectHostOrIp; ///< The TLS server host name as passed in the CONNECT request
    unsigned short tlsConnectPort; ///< The TLS server port number as passed in the CONNECT request
    SBuf sslCommonName_; ///< CN name for SSL certificate generation

    /// TLS client delivered SNI value. Empty string if none has been received.
    SBuf tlsClientSni_;
    SBuf sslBumpCertKey; ///< Key to use to store/retrieve generated certificate

    /// HTTPS server cert. fetching state for bump-ssl-server-first
    Ssl::ServerBump *sslServerBump;
    Ssl::CertSignAlgorithm signAlgorithm; ///< The signing algorithm to use
#endif

    /// the reason why we no longer write the response or nil
    const char *stoppedSending_;
    /// the reason why we no longer read the request or nil
    const char *stoppedReceiving_;

    SBuf connectionTag_; ///< clt_conn_tag=Tag annotation for client connection
};

const char *findTrailingHTTPVersion(const char *uriAndHTTPVersion, const char *end = NULL);

int varyEvaluateMatch(StoreEntry * entry, HttpRequest * req);

/// accept requests to a given port and inform subCall about them
void clientStartListeningOn(AnyP::PortCfgPointer &port, const RefCount< CommCbFunPtrCallT<CommAcceptCbPtrFun> > &subCall, const Ipc::FdNoteId noteId);

void clientOpenListenSockets(void);
void clientConnectionsClose(void);
void httpRequestFree(void *);

/// decide whether to expect multiple requests on the corresponding connection
void clientSetKeepaliveFlag(ClientHttpRequest *http);

/// append a "part" HTTP header (as in a multi-part/range reply) to the buffer
void clientPackRangeHdr(const HttpReply *, const HttpHdrRangeSpec *, String boundary, MemBuf *);

/// put terminating boundary for multiparts to the buffer
void clientPackTermBound(String boundary, MemBuf *);

/* misplaced declaratrions of Stream callbacks provided/used by client side */
SQUIDCEXTERN CSR clientGetMoreData;
SQUIDCEXTERN CSS clientReplyStatus;
SQUIDCEXTERN CSD clientReplyDetach;
CSCB clientSocketRecipient;
CSD clientSocketDetach;

void clientProcessRequest(ConnStateData *, const Http1::RequestParserPointer &, Http::Stream *);
void clientPostHttpsAccept(ConnStateData *);

std::ostream &operator <<(std::ostream &os, const ConnStateData::PinnedIdleContext &pic);

#endif /* SQUID_CLIENTSIDE_H */