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Code Issues Releases Wiki Activity

Added TCP options

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This commit is contained in:
matias
2011-08-12 08:14:29 -03:00
parent 6288574f85
commit 46c00acbc6
2 changed files with 88 additions and 13 deletions
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74
src/tcp.cpp
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@@ -30,7 +30,8 @@
const uint16_t Tins::TCP::DEFAULT_WINDOW = 32678;
Tins::TCP::TCP(uint16_t dport, uint16_t sport) : PDU(IPPROTO_TCP), _payload(0), _payload_size(0) {
Tins::TCP::TCP(uint16_t dport, uint16_t sport) : PDU(IPPROTO_TCP), _payload(0), _payload_size(0),
_options_size(0), _total_options_size(0) {
std::memset(&_tcp, 0, sizeof(tcphdr));
_tcp.dport = Utils::net_to_host_s(dport);
_tcp.sport = Utils::net_to_host_s(sport);
@@ -38,6 +39,11 @@ Tins::TCP::TCP(uint16_t dport, uint16_t sport) : PDU(IPPROTO_TCP), _payload(0),
_tcp.window = Utils::net_to_host_s(DEFAULT_WINDOW);
}
Tins::TCP::~TCP() {
for(unsigned i(0); i < _options.size(); ++i)
delete[] _options[i].data;
}
void Tins::TCP::dport(uint16_t new_dport) {
_tcp.dport = Utils::net_to_host_s(new_dport);
}
@@ -72,6 +78,16 @@ void Tins::TCP::payload(uint8_t *new_payload, uint32_t new_payload_size) {
_payload_size = new_payload_size;
}
void Tins::TCP::set_mss(uint16_t value) {
value = Utils::net_to_host_s(value);
add_option(MSS, 2, (uint8_t*)&value);
}
void Tins::TCP::set_timestamp(uint32_t value, uint32_t reply) {
uint64_t buffer = ((uint64_t)Utils::net_to_host_l(reply) << 32) | Utils::net_to_host_l(value);
add_option(TSOPT, 8, (uint8_t*)&buffer);
}
void Tins::TCP::set_flag(Flags tcp_flag, uint8_t value) {
switch(tcp_flag) {
case FIN:
@@ -101,21 +117,59 @@ void Tins::TCP::set_flag(Flags tcp_flag, uint8_t value) {
};
}
uint16_t Tins::TCP::do_checksum() const {
const uint8_t *ptr = (const uint8_t*)_payload, *end = (const uint8_t*)_payload + _payload_size;
uint16_t checksum(0);
while(ptr < end)
checksum += *(ptr++);
void Tins::TCP::add_option(Options tcp_option, uint8_t length, uint8_t *data) {
uint8_t *new_data = new uint8_t[length], padding;
memcpy(new_data, data, length);
_options.push_back(TCPOption(tcp_option, length, new_data));
_options_size += length + (sizeof(uint8_t) << 1);
padding = _options_size & 3;
_total_options_size = (padding) ? _options_size - padding + 4 : _options_size;
}
uint16_t Tins::TCP::do_checksum(uint8_t *start, uint8_t *end) const {
unsigned checksum(0);
while(start < end)
checksum += *(start++);
return checksum;
}
uint32_t Tins::TCP::header_size() const {
return sizeof(tcphdr) + _payload_size;
return sizeof(tcphdr) + _payload_size + _total_options_size;
}
void Tins::TCP::write_serialization(uint8_t *buffer, uint32_t total_sz) {
assert(total_sz >= header_size());
_tcp.check = Utils::net_to_host_s(do_checksum());
memcpy(buffer, &_tcp, sizeof(tcphdr));
memcpy(buffer + sizeof(tcphdr), _payload, _payload_size);
uint8_t *tcp_start = buffer;
buffer += sizeof(tcphdr);
_tcp.doff = (sizeof(tcphdr) + _total_options_size) / sizeof(uint32_t);
for(unsigned i(0); i < _options.size(); ++i)
buffer = _options[i].write(buffer);
if(_options_size < _total_options_size) {
uint8_t padding = _total_options_size;
while(padding < _options_size) {
*(buffer++) = 1;
padding++;
}
}
memcpy(buffer, _payload, _payload_size);
_tcp.check = Utils::net_to_host_s(do_checksum(tcp_start + sizeof(tcphdr), buffer));
memcpy(tcp_start, &_tcp, sizeof(tcphdr));
}
/* TCPOptions */
uint8_t *Tins::TCP::TCPOption::write(uint8_t *buffer) {
if(kind == 1) {
*buffer = kind;
return buffer + 1;
}
else {
buffer[0] = kind;
buffer[1] = length + (sizeof(uint8_t) << 1);
memcpy(buffer + 2, data, length);
return buffer + length + (sizeof(uint8_t) << 1);
}
}