140 lines
4.1 KiB
C++
140 lines
4.1 KiB
C++
/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
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/*
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* Copyright (c) 2014-2022, Regents of the University of California,
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* Arizona Board of Regents,
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* Colorado State University,
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* University Pierre & Marie Curie, Sorbonne University,
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* Washington University in St. Louis,
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* Beijing Institute of Technology,
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* The University of Memphis.
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*
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* This file is part of NFD (Named Data Networking Forwarding Daemon).
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* See AUTHORS.md for complete list of NFD authors and contributors.
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*
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* NFD is free software: you can redistribute it and/or modify it under the terms
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* of the GNU General Public License as published by the Free Software Foundation,
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* either version 3 of the License, or (at your option) any later version.
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*
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* NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* NFD, e.g., in COPYING.md file. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef NFD_DAEMON_FACE_PCAP_HELPER_HPP
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#define NFD_DAEMON_FACE_PCAP_HELPER_HPP
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#include "core/common.hpp"
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#ifndef NFD_HAVE_LIBPCAP
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#error "Cannot include this file when libpcap is not available"
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#endif
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// forward declarations
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struct pcap;
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typedef pcap pcap_t;
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namespace nfd::face {
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/**
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* @brief Helper class for dealing with libpcap handles.
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*/
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class PcapHelper : noncopyable
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{
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public:
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class Error : public std::runtime_error
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{
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public:
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using std::runtime_error::runtime_error;
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};
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/**
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* @brief Create a libpcap context for live packet capture on a network interface.
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* @throw Error on any error
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* @sa pcap_create(3pcap)
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*/
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explicit
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PcapHelper(const std::string& interfaceName);
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~PcapHelper() noexcept;
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/**
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* @brief Start capturing packets.
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* @param dlt The link-layer header type to be used.
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* @throw Error on any error
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* @sa pcap_activate(3pcap), pcap_set_datalink(3pcap)
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*/
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void
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activate(int dlt);
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/**
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* @brief Stop capturing and close the handle.
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* @sa pcap_close(3pcap)
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*/
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void
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close() noexcept;
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/**
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* @brief Obtain a file descriptor that can be used in calls such as select(2) and poll(2).
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* @pre activate() has been called.
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* @return A selectable file descriptor. It is the caller's responsibility to close the fd.
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* @throw Error on any error
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* @sa pcap_get_selectable_fd(3pcap)
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*/
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int
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getFd() const;
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/**
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* @brief Get last error message.
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* @return Human-readable explanation of the last libpcap error.
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* @warning The behavior is undefined if no error occurred.
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* @sa pcap_geterr(3pcap)
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*/
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std::string
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getLastError() const noexcept;
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/**
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* @brief Get the number of packets dropped by the kernel, as reported by libpcap.
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* @throw Error on any error
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* @sa pcap_stats(3pcap)
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*/
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size_t
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getNDropped() const;
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/**
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* @brief Install a BPF filter on the receiving socket.
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* @param filter Null-terminated string containing the BPF program source.
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* @pre activate() has been called.
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* @throw Error on any error
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* @sa pcap_setfilter(3pcap), pcap-filter(7)
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*/
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void
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setPacketFilter(const char* filter) const;
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/**
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* @brief Read the next packet captured on the interface.
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* @return If successful, returns a tuple containing a read-only view of the received
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* packet bytes (including the link-layer header) and a second element that
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* must be ignored. On failure, returns a tuple containing an empty span and
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* the reason for the failure.
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* @warning The returned span is valid only until the next call to this function.
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* @sa pcap_next_ex(3pcap)
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*/
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std::tuple<span<const uint8_t>, std::string>
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readNextPacket() const noexcept;
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operator pcap_t*() const noexcept
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{
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return m_pcap;
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}
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private:
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pcap_t* m_pcap = nullptr;
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};
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} // namespace nfd::face
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#endif // NFD_DAEMON_FACE_PCAP_HELPER_HPP
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