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Code Issues Releases Wiki Activity

IP and TCP now calculate checksums always inside write_serialization.

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This commit is contained in:
Matias Fontanini
2013-04-11 00:57:36 -03:00
parent 1fbef641da
commit f4522acd44
3 changed files with 37 additions and 27 deletions
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12
include/packet_writer.h
View File

@@ -98,6 +98,18 @@ public:
*/
void write(PDU &pdu);
/**
* \brief Writes a PDU to this file.
*
* The template parameter T must at some point yield a PDU& after
* applying operator* one or more than one time. This accepts both
* raw and smartpointers.
*/
template<typename T>
void write(T &pdu) {
write(Utils::dereference_until_pdu(pdu));
}
/**
* \brief Writes all the PDUs in the range [start, end)
* \param start A forward iterator pointing to the first PDU

7
src/ip.cpp
View File

@@ -378,6 +378,7 @@ void IP::prepare_for_serialize(const PDU *parent) {
void IP::write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU* parent) {
uint32_t my_sz = header_size();
assert(total_sz >= my_sz);
check(0);
if(inner_pdu()) {
uint32_t new_flag;
switch(inner_pdu()->pdu_type()) {
@@ -415,12 +416,12 @@ void IP::write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU* pare
ptr_buffer = write_option(*it, ptr_buffer);
memset(buffer + sizeof(_ip) + _options_size, 0, _padded_options_size - _options_size);
if(parent && !_ip.check) {
if(parent) {
uint32_t checksum = Utils::do_checksum(buffer, buffer + sizeof(_ip) + _padded_options_size);
while (checksum >> 16)
checksum = (checksum & 0xffff) + (checksum >> 16);
((iphdr*)buffer)->check = Endian::host_to_be<uint16_t>(~checksum);
this->check(0);
check(~checksum);
((iphdr*)buffer)->check = _ip.check;
}
}

45
src/tcp.cpp
View File

@@ -284,6 +284,7 @@ uint32_t TCP::header_size() const {
void TCP::write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU *parent) {
assert(total_sz >= header_size());
uint8_t *tcp_start = buffer;
check(0);
buffer += sizeof(tcphdr);
_tcp.doff = (sizeof(tcphdr) + _total_options_size) / sizeof(uint32_t);
for(options_type::iterator it = _options.begin(); it != _options.end(); ++it)
@@ -299,34 +300,30 @@ void TCP::write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU *par
memcpy(tcp_start, &_tcp, sizeof(tcphdr));
if(!_tcp.check) {
const Tins::IP *ip_packet = dynamic_cast<const Tins::IP*>(parent);
if(ip_packet) {
uint32_t checksum = Utils::pseudoheader_checksum(ip_packet->src_addr(),
ip_packet->dst_addr(),
size(), Constants::IP::PROTO_TCP) +
Utils::do_checksum(tcp_start, tcp_start + total_sz);
const Tins::IP *ip_packet = dynamic_cast<const Tins::IP*>(parent);
if(ip_packet) {
uint32_t checksum = Utils::pseudoheader_checksum(ip_packet->src_addr(),
ip_packet->dst_addr(),
size(), Constants::IP::PROTO_TCP) +
Utils::do_checksum(tcp_start, tcp_start + total_sz);
while (checksum >> 16)
checksum = (checksum & 0xffff) + (checksum >> 16);
check(~checksum);
((tcphdr*)tcp_start)->check = _tcp.check;
}
else {
const Tins::IPv6 *ipv6_packet = dynamic_cast<const Tins::IPv6*>(parent);
if(ipv6_packet) {
uint32_t checksum = Utils::pseudoheader_checksum(ipv6_packet->src_addr(),
ipv6_packet->dst_addr(),
size(), Constants::IP::PROTO_TCP) +
Utils::do_checksum(tcp_start, tcp_start + total_sz);
while (checksum >> 16)
checksum = (checksum & 0xffff) + (checksum >> 16);
((tcphdr*)tcp_start)->check = Endian::host_to_be<uint16_t>(~checksum);
}
else {
const Tins::IPv6 *ipv6_packet = dynamic_cast<const Tins::IPv6*>(parent);
if(ipv6_packet) {
uint32_t checksum = Utils::pseudoheader_checksum(ipv6_packet->src_addr(),
ipv6_packet->dst_addr(),
size(), Constants::IP::PROTO_TCP) +
Utils::do_checksum(tcp_start, tcp_start + total_sz);
while (checksum >> 16)
checksum = (checksum & 0xffff) + (checksum >> 16);
((tcphdr*)tcp_start)->check = Endian::host_to_be<uint16_t>(~checksum);
}
check(~checksum);
((tcphdr*)tcp_start)->check = _tcp.check;
}
}
_tcp.check = 0;
}
const TCP::option *TCP::search_option(OptionTypes opt) const {