diff options
Diffstat (limited to 'src/bin/perfdhcp/pkt_transform.h')
| -rw-r--r-- | src/bin/perfdhcp/pkt_transform.h | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/src/bin/perfdhcp/pkt_transform.h b/src/bin/perfdhcp/pkt_transform.h new file mode 100644 index 0000000..99cdb19 --- /dev/null +++ b/src/bin/perfdhcp/pkt_transform.h @@ -0,0 +1,161 @@ +// Copyright (C) 2012-2019 Internet Systems Consortium, Inc. ("ISC") +// +// This Source Code Form is subject to the terms of the Mozilla Public +// License, v. 2.0. If a copy of the MPL was not distributed with this +// file, You can obtain one at http://mozilla.org/MPL/2.0/. + +#ifndef PKT_TRANSFORM_H +#define PKT_TRANSFORM_H + +#include <perfdhcp/localized_option.h> + +#include <dhcp/option.h> + +namespace isc { +namespace perfdhcp { + +/// \brief Read and write raw data to DHCP packets. +/// +/// This class provides static functions to read/write raw data from/to the +/// packet buffer. When reading data with the unpack() method, the +/// corresponding options objects are updated. When writing to the packet +/// buffer with pack(), options objects carry input data to be written. +/// +/// This class is used both by \ref PerfPkt4 and +/// \ref PerfPkt6 classes in case DHCP packets are created +/// from template files. In this case, some of the template +/// packet's options are replaced before sending it to the +/// server. Offset of specific options are provided from the +/// command line by the perfdhcp tool user, and passed in an +/// options collection. +class PktTransform { +public: + + /// \brief Prepares on-wire format from raw buffer. + /// + /// The method copies the input buffer and options contents + /// to the output buffer. The input buffer must contain whole + /// initial packet data. Parts of this data will be + /// overridden by options data specified in an options + /// collection. Such options must have their offsets within + /// a packet specified (see \ref LocalizedOption to find out + /// how to specify options offset). + /// + /// \note The specified options must fit into the size of the + /// initial packet data. A call to this method will fail + /// if the option's offset + its size is beyond the packet's size. + /// + /// \param universe Universe used, V4 or V6 + /// \param in_buffer Input buffer holding initial packet + /// data, this can be directly read from template file + /// \param options Options collection with offsets + /// \param transid_offset offset of transaction id in a packet, + /// transaction ID will be written to output buffer at this + /// offset + /// \param transid Transaction ID value + /// \param out_buffer Output buffer holding "packed" data + /// + /// \return false, if pack operation failed. + static bool pack(const dhcp::Option::Universe universe, + const dhcp::OptionBuffer& in_buffer, + const dhcp::OptionCollection& options, + const size_t transid_offset, + const uint32_t transid, + util::OutputBuffer& out_buffer); + + /// \brief Handles selective binary packet parsing. + /// + /// This method handles the parsing of packets that have non-default + /// options or transaction ID offsets. The client class has to use + /// \ref isc::dhcp::Pkt6::addOption to specify which options to parse. + /// Each option should be of the \ref isc::perfdhcp::LocalizedOption + /// type with the offset value specified. + /// + /// \param universe universe used, V4 or V6 + /// \param in_buffer input buffer to be parsed + /// \param options options collection with options offsets + /// \param transid_offset offset of transaction id in input buffer + /// \param transid transaction id value read from input buffer + /// + /// \return false, if unpack operation failed. + static bool unpack(const dhcp::Option::Universe universe, + const dhcp::OptionBuffer& in_buffer, + const dhcp::OptionCollection& options, + const size_t transid_offset, + uint32_t& transid); + + /// \brief Replace contents of buffer with vector. + /// + /// Function replaces data of the buffer with data from vector. + /// + /// \param in_buffer destination buffer. + /// \param dest_pos position in destination buffer. + /// \param first beginning of data range in source vector. + /// \param last end of data range in source vector. + static void writeAt(dhcp::OptionBuffer& in_buffer, size_t dest_pos, + std::vector<uint8_t>::iterator first, + std::vector<uint8_t>::iterator last); + + /// \brief Replace contents of one vector with uint16 value. + /// + /// Function replaces data inside one vector with uint16_t value. + /// + /// \param in_buffer destination buffer. + /// \param dest_pos position in destination buffer. + /// \param val value to be written. + template<typename T> + static void writeValueAt(dhcp::OptionBuffer& in_buffer, size_t dest_pos, + T val) { + // @todo consider replacing the loop with switch statement + // checking sizeof(T). + for (int i = 0; i < sizeof(T); ++i) { + in_buffer[dest_pos + i] = (val >> 8 * (sizeof(T) - i - 1)) & 0xFF; + } + } + +private: + /// \brief Replaces contents of options in a buffer. + /// + /// The method uses a localized options collection to + /// replace parts of packet data (e.g. data read + /// from template file). + /// This private method is called from \ref PktTransform::pack + /// + /// \param in_buffer input buffer holding initial packet data. + /// \param out_buffer output buffer with "packed" options. + /// \param options options collection with actual data and offsets. + /// + /// \throw isc::Unexpected if options update failed. + static void packOptions(const dhcp::OptionBuffer& in_buffer, + const dhcp::OptionCollection& options, + util::OutputBuffer& out_buffer); + + /// \brief Reads contents of specified options from buffer. + /// + /// The method reads options data from the input buffer + /// and stores it in options objects. Offsets of the options + /// must be specified (see \ref LocalizedOption to find out how to specify + /// the option offset). + /// This private method is called by \ref PktTransform::unpack. + /// + /// \note This method iterates through all options in an + /// options collection, checks the offset of the option + /// in input buffer and reads data from the buffer to + /// update the option's buffer. If the provided options collection + /// is empty, a call to this method will have no effect. + /// + /// \param universe universe used, V4 or V6 + /// \param in_buffer input buffer to be parsed. + /// \param options options collection with their offsets + /// in input buffer specified. + /// + /// \throw isc::Unexpected if options unpack failed. + static void unpackOptions(const dhcp::OptionBuffer& in_buffer, + const dhcp::OptionCollection& options); + +}; + +} // namespace perfdhcp +} // namespace isc + +#endif // PKT_TRANSFORM_H |