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libtins/src/ipv6.cpp
2016-02-22 20:37:48 -08:00

292 lines
10 KiB
C++

/*
* Copyright (c) 2016, Matias Fontanini
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <cstring>
#ifndef _WIN32
#include <netinet/in.h>
#include <sys/socket.h>
#else
#include <ws2tcpip.h>
#endif
#include <algorithm>
#include "ipv6.h"
#include "constants.h"
#include "packet_sender.h"
#include "rawpdu.h"
#include "exceptions.h"
#include "pdu_allocator.h"
#include "internals.h"
#include "memory_helpers.h"
using std::copy;
using Tins::Memory::InputMemoryStream;
using Tins::Memory::OutputMemoryStream;
namespace Tins {
PDU::metadata IPv6::extract_metadata(const uint8_t *buffer, uint32_t total_sz) {
if (TINS_UNLIKELY(total_sz < sizeof(ipv6_header))) {
throw malformed_packet();
}
InputMemoryStream stream(buffer, total_sz);
const ipv6_header* header = (const ipv6_header*)buffer;
uint32_t header_size = sizeof(ipv6_header);
uint8_t current_header = header->next_header;
stream.skip(sizeof(ipv6_header));
while (is_extension_header(current_header)) {
current_header = stream.read<uint8_t>();
const uint32_t ext_size = (static_cast<uint32_t>(stream.read<uint8_t>()) + 1) * 8;
const uint32_t payload_size = ext_size - sizeof(uint8_t) * 2;
header_size += ext_size;
stream.skip(payload_size);
}
return metadata(header_size, pdu_flag, PDU::UNKNOWN);
}
IPv6::IPv6(address_type ip_dst, address_type ip_src, PDU* child)
: header_(), headers_size_(0) {
version(6);
dst_addr(ip_dst);
src_addr(ip_src);
}
IPv6::IPv6(const uint8_t* buffer, uint32_t total_sz)
: headers_size_(0) {
InputMemoryStream stream(buffer, total_sz);
stream.read(header_);
uint8_t current_header = header_.next_header;
bool is_payload_fragmented = false;
while (stream) {
if (is_extension_header(current_header)) {
if (current_header == FRAGMENT) {
is_payload_fragmented = true;
}
const uint8_t ext_type = stream.read<uint8_t>();
// every ext header is at least 8 bytes long
// minus one, from the next_header field.
const uint32_t ext_size = (static_cast<uint32_t>(stream.read<uint8_t>()) + 1) * 8;
const uint32_t payload_size = ext_size - sizeof(uint8_t) * 2;
if (!stream.can_read(ext_size)) {
throw malformed_packet();
}
// minus one, from the size field
add_ext_header(ext_header(ext_type, payload_size, stream.pointer()));
current_header = ext_type;
stream.skip(payload_size);
}
else {
if (is_payload_fragmented) {
inner_pdu(new Tins::RawPDU(stream.pointer(), stream.size()));
}
else {
inner_pdu(
Internals::pdu_from_flag(
static_cast<Constants::IP::e>(current_header),
stream.pointer(),
stream.size(),
false
)
);
if (!inner_pdu()) {
inner_pdu(
Internals::allocate<IPv6>(
current_header,
stream.pointer(),
stream.size()
)
);
if (!inner_pdu()) {
inner_pdu(new Tins::RawPDU(stream.pointer(), stream.size()));
}
}
}
// We got to an actual PDU, we're done
break;
}
}
}
bool IPv6::is_extension_header(uint8_t header_id) {
return header_id == HOP_BY_HOP || header_id == DESTINATION_ROUTING_OPTIONS
|| header_id == ROUTING || header_id == FRAGMENT || header_id == AUTHENTICATION
|| header_id == SECURITY_ENCAPSULATION || header_id == DESTINATION_OPTIONS
|| header_id == MOBILITY || header_id == NO_NEXT_HEADER;
}
void IPv6::version(small_uint<4> new_version) {
header_.version = new_version;
}
void IPv6::traffic_class(uint8_t new_traffic_class) {
#if TINS_IS_LITTLE_ENDIAN
header_.traffic_class = (new_traffic_class >> 4) & 0xf;
header_.flow_label[0] = (header_.flow_label[0] & 0x0f) | ((new_traffic_class << 4) & 0xf0);
#else
header_.traffic_class = new_traffic_class;
#endif
}
void IPv6::flow_label(small_uint<20> new_flow_label) {
#if TINS_IS_LITTLE_ENDIAN
uint32_t value = Endian::host_to_be<uint32_t>(new_flow_label);
header_.flow_label[2] = (value >> 24) & 0xff;
header_.flow_label[1] = (value >> 16) & 0xff;
header_.flow_label[0] = ((value >> 8) & 0x0f) | (header_.flow_label[0] & 0xf0);
#else
header_.flow_label = new_flow_label;
#endif
}
void IPv6::payload_length(uint16_t new_payload_length) {
header_.payload_length = Endian::host_to_be(new_payload_length);
}
void IPv6::next_header(uint8_t new_next_header) {
header_.next_header = new_next_header;
}
void IPv6::hop_limit(uint8_t new_hop_limit) {
header_.hop_limit = new_hop_limit;
}
void IPv6::src_addr(const address_type& new_src_addr) {
new_src_addr.copy(header_.src_addr);
}
void IPv6::dst_addr(const address_type& new_dst_addr) {
new_dst_addr.copy(header_.dst_addr);
}
uint32_t IPv6::header_size() const {
return sizeof(header_) + headers_size_;
}
bool IPv6::matches_response(const uint8_t* ptr, uint32_t total_sz) const {
if (total_sz < sizeof(ipv6_header)) {
return false;
}
const ipv6_header* hdr_ptr = (const ipv6_header*)ptr;
// checks for ff02 multicast
if (src_addr() == hdr_ptr->dst_addr &&
(dst_addr() == hdr_ptr->src_addr || (header_.dst_addr[0] == 0xff && header_.dst_addr[1] == 0x02))) {
// is this OK? there's no inner pdu, simple dst/src addr match should suffice
if (!inner_pdu()) {
return true;
}
ptr += sizeof(ipv6_header);
total_sz -= sizeof(ipv6_header);
uint8_t current = hdr_ptr->next_header;
// 8 == minimum header size
while (total_sz > 8 && is_extension_header(current)) {
if (static_cast<uint32_t>(ptr[1] + 1) * 8 > total_sz) {
return false;
}
current = ptr[0];
total_sz -= (ptr[1] + 1) * 8;
ptr += (ptr[1] + 1) * 8;
}
if (!is_extension_header(current)) {
return inner_pdu()->matches_response(ptr, total_sz);
}
}
return false;
}
void IPv6::write_serialization(uint8_t* buffer, uint32_t total_sz, const PDU* parent) {
OutputMemoryStream stream(buffer, total_sz);
if (inner_pdu()) {
uint8_t new_flag = Internals::pdu_flag_to_ip_type(inner_pdu()->pdu_type());
if (new_flag == 0xff && Internals::pdu_type_registered<IPv6>(inner_pdu()->pdu_type())) {
new_flag = static_cast<Constants::IP::e>(
Internals::pdu_type_to_id<IPv6>(inner_pdu()->pdu_type())
);
}
if (new_flag != 0xff) {
set_last_next_header(new_flag);
}
}
payload_length(static_cast<uint16_t>(total_sz - sizeof(header_)));
stream.write(header_);
for (headers_type::const_iterator it = ext_headers_.begin(); it != ext_headers_.end(); ++it) {
write_header(*it, stream);
}
}
#ifndef BSD
void IPv6::send(PacketSender& sender, const NetworkInterface &) {
struct sockaddr_in6 link_addr;
PacketSender::SocketType type = PacketSender::IPV6_SOCKET;
link_addr.sin6_family = AF_INET6;
link_addr.sin6_port = 0;
copy(header_.dst_addr, header_.dst_addr + address_type::address_size, (uint8_t*)&link_addr.sin6_addr);
if (inner_pdu() && inner_pdu()->pdu_type() == PDU::ICMP) {
type = PacketSender::ICMP_SOCKET;
}
sender.send_l3(*this, (struct sockaddr*)&link_addr, sizeof(link_addr), type);
}
#endif
void IPv6::add_ext_header(const ext_header& header) {
ext_headers_.push_back(header);
headers_size_ += static_cast<uint32_t>(header.data_size() + sizeof(uint8_t) * 2);
}
const IPv6::ext_header* IPv6::search_header(ExtensionHeader id) const {
uint8_t current_header = header_.next_header;
headers_type::const_iterator it = ext_headers_.begin();
while (it != ext_headers_.end() && current_header != id) {
current_header = it->option();
++it;
}
if (it == ext_headers_.end()) {
return 0;
}
return &*it;
}
void IPv6::set_last_next_header(uint8_t value) {
if (ext_headers_.empty()) {
header_.next_header = value;
}
else {
ext_headers_.back().option(value);
}
}
void IPv6::write_header(const ext_header& header, OutputMemoryStream& stream) {
const uint8_t length = header.length_field() / 8;
stream.write(header.option());
stream.write(length);
stream.write(header.data_ptr(), header.data_size());
}
} // Tins