1558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch// Copyright 2013 The Chromium Authors. All rights reserved. 2558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch// Use of this source code is governed by a BSD-style license that can be 3558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch// found in the LICENSE file. 4558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 5558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch#include "chrome/browser/net/probe_message.h" 6558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 7558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch#include <string> 8558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 9558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch#include "base/logging.h" 10558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 11558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochnamespace chrome_browser_net { 12558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 13558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochconst uint32 ProbeMessage::kVersion = 2; 14558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochconst uint32 ProbeMessage::kMaxNumberProbePackets = 21; 15558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochconst uint32 ProbeMessage::kMaxProbePacketBytes = 1500; 16f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles)// Maximum pacing interval is 300 seconds (for testing NAT binding). 17558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochconst uint32 ProbeMessage::kMaxPacingIntervalMicros = 300000000; 18558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochconst char ProbeMessage::kEncodingString[] = 19558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch "T\xd3?\xa5h2\x9c\x8en\xf1Q6\xbc{\xc6-4\xfa$f\xb9[\xa6\xcd@6,\xdf\xb3i-\xe6" 20558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch "v\x9eV\x8dXd\xd9kE\xf6=\xbeO"; 21558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 22558790d6acca3451cf3a6b497803a5f07d0bec58Ben MurdochProbeMessage::ProbeMessage() {} 23558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 24558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochbool ProbeMessage::ParseInput(const std::string& input, 25558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch ProbePacket* probe_packet) const { 26558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch // Encode is used for decoding here. 27558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch std::string input_decoded = Encode(input); 28558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 29558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch bool parse_result = probe_packet->ParseFromString(input_decoded); 30558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch if (!parse_result) { 31558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DVLOG(1) << "ProtoBuffer string parsing error. Input size:" << input.size(); 32558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch return false; 33558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch } 34558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch const ProbePacket_Header& header = probe_packet->header(); 35558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DVLOG(2) << "version " << header.version() << " checksum " 36558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch << header.checksum() << " type " << header.type(); 37558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch if (header.version() != kVersion) { 38558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DVLOG(1) << "Bad version number: " << header.version() 39558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch << " expected: " << kVersion; 40558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch return false; 41558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch } 42558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 43558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch // Checksum is computed on padding only. 44558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch if (probe_packet->has_padding()) { 45558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DVLOG(3) << "received padding: " << probe_packet->padding(); 46558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch uint32 computed_checksum = Checksum(probe_packet->padding()); 47558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch if (computed_checksum != header.checksum()) { 48558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DVLOG(1) << "Checksum mismatch. Got: " << header.checksum() 49558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch << " expected: " << computed_checksum; 50558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch return false; 51558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch } 52558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch } 53558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 54558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch if (header.type() != ProbePacket_Type_HELLO_REPLY && 55558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch header.type() != ProbePacket_Type_PROBE_REPLY) { 56558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DVLOG(1) << "Received unknown packet type:" << header.type(); 57558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch return false; 58558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch } 59558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch return true; 60558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch} 61558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 62558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochuint32 ProbeMessage::Checksum(const std::string& str) const { 63558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch uint32 ret = 0; 64558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch for (std::string::const_iterator i = str.begin(); i != str.end(); ++i) { 65558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch ret += static_cast<uint8>(*i); 66558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch } 67558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch return ret; 68558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch} 69558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 70558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochvoid ProbeMessage::GenerateProbeRequest(const ProbePacket_Token& token, 71558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch uint32 group_id, 72558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch uint32 probe_size, 73558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch uint32 pacing_interval_micros, 74558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch uint32 number_probe_packets, 75558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch ProbePacket* probe_packet) { 76558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DCHECK_LE(number_probe_packets, kMaxNumberProbePackets); 77558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DCHECK_LE(probe_size, kMaxProbePacketBytes); 78558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DCHECK_LE(pacing_interval_micros, kMaxPacingIntervalMicros); 79558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 80558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch SetPacketHeader(ProbePacket_Type_PROBE_REQUEST, probe_packet); 81558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch *(probe_packet->mutable_token()) = token; 82558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch probe_packet->set_group_id(group_id); 83558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch probe_packet->set_probe_size_bytes(probe_size); 84558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch probe_packet->set_pacing_interval_micros(pacing_interval_micros); 85558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch probe_packet->set_number_probe_packets(number_probe_packets); 86558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 87558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch // Add padding to mitigate amplification attack. 88558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch std::string* padding = probe_packet->mutable_padding(); 89558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch int padding_size = probe_size - probe_packet->ByteSize(); 90558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch padding->append(std::string(std::max(0, padding_size), 0)); 91558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch probe_packet->mutable_header()->set_checksum(Checksum(*padding)); 92558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DVLOG(3) << "Request size " << probe_packet->ByteSize() << " probe size " 93558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch << probe_size; 94558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch DCHECK_LE(probe_size, static_cast<uint32>(probe_packet->ByteSize())); 95558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch} 96558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 97558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochvoid ProbeMessage::SetPacketHeader(ProbePacket_Type packet_type, 98558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch ProbePacket* probe_packet) const { 99558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch ProbePacket_Header* header = probe_packet->mutable_header(); 100558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch header->set_version(kVersion); 101558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch header->set_type(packet_type); 102558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch} 103558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 104558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochstd::string ProbeMessage::Encode(const std::string& input) const { 105558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 106558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch std::string output(input.size(), 0); 107558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch int key_pos = 0; 108558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch // kEncodingString contains a ending '\0' character, excluded for encoding. 109558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch int key_size = sizeof(kEncodingString) - 1; 110558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch for (size_t i = 0; i < input.size(); ++i) { 111558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch output[i] = input[i] ^ kEncodingString[key_pos]; 112558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch ++key_pos; 113558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch if (key_pos >= key_size) 114558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch key_pos = 0; 115558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch } 116558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch return output; 117558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch} 118558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 119558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdochstd::string ProbeMessage::MakeEncodedPacket( 120558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch const ProbePacket& probe_packet) const { 121558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch std::string output; 122558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch probe_packet.SerializeToString(&output); 123558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch return Encode(output); 124558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch} 125558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch 126558790d6acca3451cf3a6b497803a5f07d0bec58Ben Murdoch} // namespace chrome_browser_net 127