/*
 * 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_SECURITY_PEEROPTIONS_H
#define SQUID_SRC_SECURITY_PEEROPTIONS_H

#include "base/YesNoNone.h"
#include "ConfigParser.h"
#include "security/Context.h"
#include "security/forward.h"
#include "security/KeyData.h"
#include "security/Session.h"

class Packable;

namespace Security
{

/// TLS squid.conf settings for a remote server peer
class PeerOptions
{
public:
    PeerOptions();
    PeerOptions(const PeerOptions &) = default;
    PeerOptions &operator =(const PeerOptions &) = default;
    PeerOptions(PeerOptions &&) = default;
    PeerOptions &operator =(PeerOptions &&) = default;
    virtual ~PeerOptions() {}

    /// parse a TLS squid.conf option
    virtual void parse(const char *);

    /// parse and verify the [tls-]options= string in sslOptions
    void parseOptions();

    /// reset the configuration details to default
    virtual void clear() {*this = PeerOptions();}

    /// generate an unset security context object
    virtual Security::ContextPointer createBlankContext() const;

    /// generate a security client-context from these configured options
    Security::ContextPointer createClientContext(bool setOptions);

    /// sync the context options with tls-min-version=N configuration
    void updateTlsVersionLimits();

    /// Setup the library specific 'options=' parameters for the given context.
    void updateContextOptions(Security::ContextPointer &);

    /// setup the NPN extension details for the given context
    void updateContextNpn(Security::ContextPointer &);

    /// setup the CA details for the given context
    void updateContextCa(Security::ContextPointer &);

    /// setup the CRL details for the given context
    void updateContextCrl(Security::ContextPointer &);

    /// decide which CAs to trust
    void updateContextTrust(Security::ContextPointer &);

    /// setup any library-specific options that can be set for the given session
    void updateSessionOptions(Security::SessionPointer &);

    /// output squid.conf syntax with 'pfx' prefix on parameters for the stored settings
    virtual void dumpCfg(std::ostream &, const char *pfx) const;

private:
    ParsedPortFlags parseFlags();
    void loadCrlFile();
    void loadKeysFile();

public:
    SBuf sslOptions;     ///< library-specific options string
    SBuf caDir;          ///< path of directory containing a set of trusted Certificate Authorities
    SBuf crlFile;        ///< path of file containing Certificate Revoke List

    SBuf sslCipher;
    SBuf sslFlags;       ///< flags defining what TLS operations Squid performs
    SBuf sslDomain;

    SBuf tlsMinVersion;  ///< version label for minimum TLS version to permit

private:
    /// Library-specific options string generated from tlsMinVersion.
    /// Call updateTlsVersionLimits() to regenerate this string.
    SBuf tlsMinOptions;

    /// Parsed value of sslOptions + tlsMinOptions settings.
    /// Set optsReparse=true to have this re-parsed before next use.
    Security::ParsedOptions parsedOptions;

    /// whether parsedOptions content needs to be regenerated
    bool optsReparse = true;

public:
    ParsedPortFlags parsedFlags = 0; ///< parsed value of sslFlags

    std::list<Security::KeyData> certs; ///< details from the cert= and file= config parameters
    std::list<SBuf> caFiles;  ///< paths of files containing trusted Certificate Authority
    Security::CertRevokeList parsedCrl; ///< CRL to use when verifying the remote end certificate

protected:
    template<typename T>
    Security::ContextPointer convertContextFromRawPtr(T ctx) const {
#if USE_OPENSSL
        debugs(83, 5, "SSL_CTX construct, this=" << (void*)ctx);
        return ContextPointer(ctx, [](SSL_CTX *p) {
            debugs(83, 5, "SSL_CTX destruct, this=" << (void*)p);
            SSL_CTX_free(p);
        });
#elif HAVE_LIBGNUTLS
        debugs(83, 5, "gnutls_certificate_credentials construct, this=" << (void*)ctx);
        return Security::ContextPointer(ctx, [](gnutls_certificate_credentials_t p) {
            debugs(83, 5, "gnutls_certificate_credentials destruct, this=" << (void*)p);
            gnutls_certificate_free_credentials(p);
        });
#else
        assert(!ctx);
        return Security::ContextPointer();
#endif
    }

    int sslVersion = 0;

    /// flags governing Squid internal TLS operations
    struct flags_ {
        flags_() : tlsDefaultCa(true), tlsNpn(true) {}
        flags_(const flags_ &) = default;
        flags_ &operator =(const flags_ &) = default;

        /// whether to use the system default Trusted CA when verifying the remote end certificate
        YesNoNone tlsDefaultCa;

        /// whether to use the TLS NPN extension on these connections
        bool tlsNpn;
    } flags;

public:
    /// whether transport encryption (TLS/SSL) is to be used on connections to the peer
    bool encryptTransport = false;
};

// XXX: Remove this shim after upgrading legacy code to store PeerContext
// objects instead of disjoint PeerOptons and Context objects (where PeerContext
// is a class that creates and manages {PeerOptions, ContextPointer} pair).
/// A combination of PeerOptions and the corresponding Context.
class FuturePeerContext
{
public:
    FuturePeerContext(PeerOptions &o, const ContextPointer &c): options(o), raw(c) {}

    PeerOptions &options; ///< TLS context configuration
    const ContextPointer &raw; ///< TLS context configured using options
};

/// configuration options for DIRECT server access
extern PeerOptions ProxyOutgoingConfig;

} // namespace Security

// parse the tls_outgoing_options directive
void parse_securePeerOptions(Security::PeerOptions *);
#define free_securePeerOptions(x) Security::ProxyOutgoingConfig.clear()
#define dump_securePeerOptions(e,n,x) do { PackableStream os_(*(e)); os_ << n; (x).dumpCfg(os_,""); os_ << '\n'; } while (false)

#endif /* SQUID_SRC_SECURITY_PEEROPTIONS_H */