HttpUpgradeProtocolAccess.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_SRC_HTTPUPGRADEPROTOCOLACCESS_H
#define SQUID_SRC_HTTPUPGRADEPROTOCOLACCESS_H
 
#include "acl/forward.h"
#include "sbuf/SBuf.h"
 
#include <deque>
#include <map>
 
class ProtocolView
{
public:
    ProtocolView(const char * const start, const size_t len);
    explicit ProtocolView(const SBuf &proto);
 
    SBuf name; 
    SBuf version; 
};
 
std::ostream &operator <<(std::ostream &, const ProtocolView &);
 
// HTTP is not explicit about case sensitivity of Upgrade protocol strings, but
// there are bug reports showing different case variants used for WebSocket. We
// conservatively preserve the received case and compare case-sensitively.
 
inline bool
vAinB(const ProtocolView &a, const ProtocolView &b)
{
    // Optimization: Do not assert(a.name == b.name).
    return b.version.isEmpty() || (a.version == b.version);
}
 
class ConfigParser;
 
class HttpUpgradeProtocolAccess
{
public:
    HttpUpgradeProtocolAccess() = default;
    ~HttpUpgradeProtocolAccess();
    HttpUpgradeProtocolAccess(HttpUpgradeProtocolAccess &&) = delete; // no copying of any kind
 
    const acl_access *findGuard(const SBuf &proto) const;
 
    void configureGuard(ConfigParser&);
 
    template <typename Visitor> inline void forEach(const Visitor &) const;
 
    template <typename Visitor> inline void forApplicable(const ProtocolView &, const Visitor &) const;
 
private:
    class NamedGuard
    {
    public:
        NamedGuard(const char *rawProtocol, acl_access*);
        NamedGuard(const NamedGuard &&) = delete; // no copying of any kind
        ~NamedGuard();
 
        const SBuf protocol; 
        const ProtocolView proto; 
        acl_access *guard = nullptr; 
    };
 
    typedef std::deque<NamedGuard> NamedGuards;
 
    inline static const SBuf &ProtoOther();
 
    NamedGuards namedGuards;
 
    acl_access *other = nullptr;
};
 
template <typename Visitor>
inline void
HttpUpgradeProtocolAccess::forEach(const Visitor &visitor) const
{
    for (const auto &namedGuard: namedGuards)
        visitor(namedGuard.protocol, namedGuard.guard);
    if (other)
        visitor(ProtoOther(), other);
}
 
template <typename Visitor>
inline void
HttpUpgradeProtocolAccess::forApplicable(const ProtocolView &offer, const Visitor &visitor) const
{
    auto seenApplicable = false;
    for (const auto &namedGuard: namedGuards) {
        if (offer.name != namedGuard.proto.name)
            continue;
        if (vAinB(offer, namedGuard.proto) && visitor(namedGuard.protocol, namedGuard.guard))
            return;
        seenApplicable = true; // may already be true
    }
    if (!seenApplicable && other) // OTHER is applicable if named rules were not
        (void)visitor(ProtoOther(), other);
}
 
inline const SBuf &
HttpUpgradeProtocolAccess::ProtoOther()
{
    static const auto proto = new SBuf("OTHER");
    return *proto;
}
 
#endif /* SQUID_SRC_HTTPUPGRADEPROTOCOLACCESS_H */