mirror of
https://github.com/mfontanini/libtins
synced 2026-01-24 11:11:35 +01:00
89 lines
2.9 KiB
C++
89 lines
2.9 KiB
C++
/*
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* libtins is a net packet wrapper library for crafting and
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* interpreting sniffed packets.
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*
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* Copyright (C) 2011 Nasel
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdexcept>
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#include <cassert>
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#include <cstring>
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#include "udp.h"
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#include "constants.h"
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#include "ip.h"
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#include "rawpdu.h"
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Tins::UDP::UDP(uint16_t dport, uint16_t sport, PDU *child)
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: PDU(Constants::IP::PROTO_UDP, child)
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{
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this->dport(dport);
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this->sport(sport);
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_udp.check = 0;
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_udp.len = 0;
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}
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Tins::UDP::UDP(const uint8_t *buffer, uint32_t total_sz)
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: PDU(Constants::IP::PROTO_UDP)
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{
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if(total_sz < sizeof(udphdr))
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throw std::runtime_error("Not enough size for an UDP header in the buffer.");
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std::memcpy(&_udp, buffer, sizeof(udphdr));
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total_sz -= sizeof(udphdr);
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if(total_sz)
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inner_pdu(new RawPDU(buffer + sizeof(udphdr), total_sz));
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}
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void Tins::UDP::payload(uint8_t *new_payload, uint32_t new_payload_size) {
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inner_pdu(new RawPDU(new_payload, new_payload_size));
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}
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void Tins::UDP::dport(uint16_t new_dport) {
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_udp.dport = Utils::host_to_be(new_dport);
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}
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void Tins::UDP::sport(uint16_t new_sport) {
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_udp.sport = Utils::host_to_be(new_sport);
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}
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void Tins::UDP::length(uint16_t new_len) {
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_udp.len = Utils::host_to_be(new_len);
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}
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uint32_t Tins::UDP::header_size() const {
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return sizeof(udphdr);
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}
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void Tins::UDP::write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU *parent) {
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assert(total_sz >= sizeof(udphdr));
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const Tins::IP *ip_packet = dynamic_cast<const Tins::IP*>(parent);
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if(inner_pdu())
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length(sizeof(udphdr) + inner_pdu()->size());
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std::memcpy(buffer, &_udp, sizeof(udphdr));
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if(!_udp.check && ip_packet) {
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uint32_t checksum = Utils::pseudoheader_checksum(ip_packet->src_addr(), ip_packet->dst_addr(), size(), Constants::IP::PROTO_UDP) +
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Utils::do_checksum(buffer, buffer + total_sz);
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while (checksum >> 16)
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checksum = (checksum & 0xffff)+(checksum >> 16);
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((udphdr*)buffer)->check = Utils::host_to_be<uint16_t>(~checksum);
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}
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_udp.check = 0;
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}
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void Tins::UDP::copy_fields(const UDP *other) {
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std::memcpy(&_udp, &other->_udp, sizeof(_udp));
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}
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