libzmq/src/mechanism.cpp

/* SPDX-License-Identifier: MPL-2.0 */

#include "precompiled.hpp"
#include <string.h>
#include <limits.h>

#include "mechanism.hpp"
#include "options.hpp"
#include "msg.hpp"
#include "err.hpp"
#include "wire.hpp"
#include "session_base.hpp"

zmq::mechanism_t::mechanism_t (const options_t &options_) : options (options_)
{
}

zmq::mechanism_t::~mechanism_t ()
{
}

void zmq::mechanism_t::set_peer_routing_id (const void *id_ptr_,
                                            size_t id_size_)
{
    _routing_id.set (static_cast<const unsigned char *> (id_ptr_), id_size_);
}

void zmq::mechanism_t::peer_routing_id (msg_t *msg_)
{
    const int rc = msg_->init_size (_routing_id.size ());
    errno_assert (rc == 0);
    memcpy (msg_->data (), _routing_id.data (), _routing_id.size ());
    msg_->set_flags (msg_t::routing_id);
}

void zmq::mechanism_t::set_user_id (const void *user_id_, size_t size_)
{
    _user_id.set (static_cast<const unsigned char *> (user_id_), size_);
    _zap_properties.ZMQ_MAP_INSERT_OR_EMPLACE (
      std::string (ZMQ_MSG_PROPERTY_USER_ID),
      std::string (reinterpret_cast<const char *> (user_id_), size_));
}

const zmq::blob_t &zmq::mechanism_t::get_user_id () const
{
    return _user_id;
}

const char socket_type_pair[] = "PAIR";
const char socket_type_pub[] = "PUB";
const char socket_type_sub[] = "SUB";
const char socket_type_req[] = "REQ";
const char socket_type_rep[] = "REP";
const char socket_type_dealer[] = "DEALER";
const char socket_type_router[] = "ROUTER";
const char socket_type_pull[] = "PULL";
const char socket_type_push[] = "PUSH";
const char socket_type_xpub[] = "XPUB";
const char socket_type_xsub[] = "XSUB";
const char socket_type_stream[] = "STREAM";
#ifdef ZMQ_BUILD_DRAFT_API
const char socket_type_server[] = "SERVER";
const char socket_type_client[] = "CLIENT";
const char socket_type_radio[] = "RADIO";
const char socket_type_dish[] = "DISH";
const char socket_type_gather[] = "GATHER";
const char socket_type_scatter[] = "SCATTER";
const char socket_type_dgram[] = "DGRAM";
const char socket_type_peer[] = "PEER";
const char socket_type_channel[] = "CHANNEL";
#endif

const char *zmq::mechanism_t::socket_type_string (int socket_type_)
{
    // TODO the order must of the names must correspond to the values resp. order of ZMQ_* socket type definitions in zmq.h!
    static const char *names[] = {socket_type_pair,   socket_type_pub,
                                  socket_type_sub,    socket_type_req,
                                  socket_type_rep,    socket_type_dealer,
                                  socket_type_router, socket_type_pull,
                                  socket_type_push,   socket_type_xpub,
                                  socket_type_xsub,   socket_type_stream,
#ifdef ZMQ_BUILD_DRAFT_API
                                  socket_type_server, socket_type_client,
                                  socket_type_radio,  socket_type_dish,
                                  socket_type_gather, socket_type_scatter,
                                  socket_type_dgram,  socket_type_peer,
                                  socket_type_channel
#endif
    };
    static const size_t names_count = sizeof (names) / sizeof (names[0]);
    zmq_assert (socket_type_ >= 0
                && socket_type_ < static_cast<int> (names_count));
    return names[socket_type_];
}

const size_t name_len_size = sizeof (unsigned char);
const size_t value_len_size = sizeof (uint32_t);

static size_t property_len (size_t name_len_, size_t value_len_)
{
    return name_len_size + name_len_ + value_len_size + value_len_;
}

static size_t name_len (const char *name_)
{
    const size_t name_len = strlen (name_);
    zmq_assert (name_len <= UCHAR_MAX);
    return name_len;
}

size_t zmq::mechanism_t::add_property (unsigned char *ptr_,
                                       size_t ptr_capacity_,
                                       const char *name_,
                                       const void *value_,
                                       size_t value_len_)
{
    const size_t name_len = ::name_len (name_);
    const size_t total_len = ::property_len (name_len, value_len_);
    zmq_assert (total_len <= ptr_capacity_);

    *ptr_ = static_cast<unsigned char> (name_len);
    ptr_ += name_len_size;
    memcpy (ptr_, name_, name_len);
    ptr_ += name_len;
    zmq_assert (value_len_ <= 0x7FFFFFFF);
    put_uint32 (ptr_, static_cast<uint32_t> (value_len_));
    ptr_ += value_len_size;
    memcpy (ptr_, value_, value_len_);

    return total_len;
}

size_t zmq::mechanism_t::property_len (const char *name_, size_t value_len_)
{
    return ::property_len (name_len (name_), value_len_);
}

#define ZMTP_PROPERTY_SOCKET_TYPE "Socket-Type"
#define ZMTP_PROPERTY_IDENTITY "Identity"

size_t zmq::mechanism_t::add_basic_properties (unsigned char *ptr_,
                                               size_t ptr_capacity_) const
{
    unsigned char *ptr = ptr_;

    //  Add socket type property
    const char *socket_type = socket_type_string (options.type);
    ptr += add_property (ptr, ptr_capacity_, ZMTP_PROPERTY_SOCKET_TYPE,
                         socket_type, strlen (socket_type));

    //  Add identity (aka routing id) property
    if (options.type == ZMQ_REQ || options.type == ZMQ_DEALER
        || options.type == ZMQ_ROUTER) {
        ptr += add_property (ptr, ptr_capacity_ - (ptr - ptr_),
                             ZMTP_PROPERTY_IDENTITY, options.routing_id,
                             options.routing_id_size);
    }


    for (std::map<std::string, std::string>::const_iterator
           it = options.app_metadata.begin (),
           end = options.app_metadata.end ();
         it != end; ++it) {
        ptr +=
          add_property (ptr, ptr_capacity_ - (ptr - ptr_), it->first.c_str (),
                        it->second.c_str (), strlen (it->second.c_str ()));
    }

    return ptr - ptr_;
}

size_t zmq::mechanism_t::basic_properties_len () const
{
    const char *socket_type = socket_type_string (options.type);
    size_t meta_len = 0;

    for (std::map<std::string, std::string>::const_iterator
           it = options.app_metadata.begin (),
           end = options.app_metadata.end ();
         it != end; ++it) {
        meta_len +=
          property_len (it->first.c_str (), strlen (it->second.c_str ()));
    }

    return property_len (ZMTP_PROPERTY_SOCKET_TYPE, strlen (socket_type))
           + meta_len
           + ((options.type == ZMQ_REQ || options.type == ZMQ_DEALER
               || options.type == ZMQ_ROUTER)
                ? property_len (ZMTP_PROPERTY_IDENTITY, options.routing_id_size)
                : 0);
}

void zmq::mechanism_t::make_command_with_basic_properties (
  msg_t *msg_, const char *prefix_, size_t prefix_len_) const
{
    const size_t command_size = prefix_len_ + basic_properties_len ();
    const int rc = msg_->init_size (command_size);
    errno_assert (rc == 0);

    unsigned char *ptr = static_cast<unsigned char *> (msg_->data ());

    //  Add prefix
    memcpy (ptr, prefix_, prefix_len_);
    ptr += prefix_len_;

    add_basic_properties (
      ptr, command_size - (ptr - static_cast<unsigned char *> (msg_->data ())));
}

int zmq::mechanism_t::parse_metadata (const unsigned char *ptr_,
                                      size_t length_,
                                      bool zap_flag_)
{
    size_t bytes_left = length_;

    while (bytes_left > 1) {
        const size_t name_length = static_cast<size_t> (*ptr_);
        ptr_ += name_len_size;
        bytes_left -= name_len_size;
        if (bytes_left < name_length)
            break;

        const std::string name =
          std::string (reinterpret_cast<const char *> (ptr_), name_length);
        ptr_ += name_length;
        bytes_left -= name_length;
        if (bytes_left < value_len_size)
            break;

        const size_t value_length = static_cast<size_t> (get_uint32 (ptr_));
        ptr_ += value_len_size;
        bytes_left -= value_len_size;
        if (bytes_left < value_length)
            break;

        const uint8_t *value = ptr_;
        ptr_ += value_length;
        bytes_left -= value_length;

        if (name == ZMTP_PROPERTY_IDENTITY && options.recv_routing_id)
            set_peer_routing_id (value, value_length);
        else if (name == ZMTP_PROPERTY_SOCKET_TYPE) {
            if (!check_socket_type (reinterpret_cast<const char *> (value),
                                    value_length)) {
                errno = EINVAL;
                return -1;
            }
        } else {
            const int rc = property (name, value, value_length);
            if (rc == -1)
                return -1;
        }
        (zap_flag_ ? _zap_properties : _zmtp_properties)
          .ZMQ_MAP_INSERT_OR_EMPLACE (
            name,
            std::string (reinterpret_cast<const char *> (value), value_length));
    }
    if (bytes_left > 0) {
        errno = EPROTO;
        return -1;
    }
    return 0;
}

int zmq::mechanism_t::property (const std::string & /* name_ */,
                                const void * /* value_ */,
                                size_t /* length_ */)
{
    //  Default implementation does not check
    //  property values and returns 0 to signal success.
    return 0;
}

template <size_t N>
static bool strequals (const char *actual_type_,
                       const size_t actual_len_,
                       const char (&expected_type_)[N])
{
    return actual_len_ == N - 1
           && memcmp (actual_type_, expected_type_, N - 1) == 0;
}

bool zmq::mechanism_t::check_socket_type (const char *type_,
                                          const size_t len_) const
{
    switch (options.type) {
        case ZMQ_REQ:
            return strequals (type_, len_, socket_type_rep)
                   || strequals (type_, len_, socket_type_router);
        case ZMQ_REP:
            return strequals (type_, len_, socket_type_req)
                   || strequals (type_, len_, socket_type_dealer);
        case ZMQ_DEALER:
            return strequals (type_, len_, socket_type_rep)
                   || strequals (type_, len_, socket_type_dealer)
                   || strequals (type_, len_, socket_type_router);
        case ZMQ_ROUTER:
            return strequals (type_, len_, socket_type_req)
                   || strequals (type_, len_, socket_type_dealer)
                   || strequals (type_, len_, socket_type_router);
        case ZMQ_PUSH:
            return strequals (type_, len_, socket_type_pull);
        case ZMQ_PULL:
            return strequals (type_, len_, socket_type_push);
        case ZMQ_PUB:
            return strequals (type_, len_, socket_type_sub)
                   || strequals (type_, len_, socket_type_xsub);
        case ZMQ_SUB:
            return strequals (type_, len_, socket_type_pub)
                   || strequals (type_, len_, socket_type_xpub);
        case ZMQ_XPUB:
            return strequals (type_, len_, socket_type_sub)
                   || strequals (type_, len_, socket_type_xsub);
        case ZMQ_XSUB:
            return strequals (type_, len_, socket_type_pub)
                   || strequals (type_, len_, socket_type_xpub);
        case ZMQ_PAIR:
            return strequals (type_, len_, socket_type_pair);
#ifdef ZMQ_BUILD_DRAFT_API
        case ZMQ_SERVER:
            return strequals (type_, len_, socket_type_client);
        case ZMQ_CLIENT:
            return strequals (type_, len_, socket_type_server);
        case ZMQ_RADIO:
            return strequals (type_, len_, socket_type_dish);
        case ZMQ_DISH:
            return strequals (type_, len_, socket_type_radio);
        case ZMQ_GATHER:
            return strequals (type_, len_, socket_type_scatter);
        case ZMQ_SCATTER:
            return strequals (type_, len_, socket_type_gather);
        case ZMQ_DGRAM:
            return strequals (type_, len_, socket_type_dgram);
        case ZMQ_PEER:
            return strequals (type_, len_, socket_type_peer);
        case ZMQ_CHANNEL:
            return strequals (type_, len_, socket_type_channel);
#endif
        default:
            break;
    }
    return false;
}