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Code Issues Releases Wiki Activity

TCP now stores options when instantiated from a buffer.

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This commit is contained in:
Matias Fontanini
2011-08-19 11:40:13 -03:00
parent 03aa49428c
commit 2513488b92
3 changed files with 106 additions and 46 deletions
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83
include/tcp.h
View File

@@ -23,7 +23,7 @@
#define __TCP_H
#include <vector>
#include <list>
#include <stdint.h>
#ifndef WIN32
#include <endian.h>
@@ -66,9 +66,35 @@ namespace Tins {
*/
enum Options {
MSS = 2,
EOL = 0,
NOP = 1,
MSS = 2,
TSOPT = 8
};
/**
* \brief Class that represents a TCP option field.
*/
struct TCPOption {
/**
* \brief Creates an instance of a TCPOption.
* \param okind The option kind.
* \param olength The option's data length.
* \param odata The option's data(if any).
*/
TCPOption(uint8_t okind, uint8_t olength, uint8_t *odata) :
kind(okind), length(olength), data(odata) { }
/**
* \brief Writes the option into a buffer.
* \param buffer The buffer in which to write the option.
* \return The buffer pointer incremented by the size of this option.
*/
uint8_t *write(uint8_t *buffer);
uint8_t kind, length;
uint8_t *data;
};
/**
* \brief TCP constructor.
@@ -151,6 +177,13 @@ namespace Tins {
*/
inline uint8_t data_offset() const { return this->_tcp.doff; }
/**
* \brief Getter for the option list.
*
* \return The options list.
*/
inline const std::list<TCPOption> &options() const { return _options; }
/**
* \brief Gets the value of a flag.
*
@@ -164,56 +197,56 @@ namespace Tins {
/**
* \brief Setter for the destination port field.
*
* \param new_dport uint16_t with the new destination port.
* \param new_dport The new destination port.
*/
void dport(uint16_t new_dport);
/**
* \brief Setter for the source port field.
*
* \param new_sport uint16_t with the new source port.
* \param new_sport The new source port.
*/
void sport(uint16_t new_sport);
/**
* \brief Setter for the sequence number.
*
* \param new_seq uint32_t with the new sequence number.
* \param new_seq The new sequence number.
*/
void seq(uint32_t new_seq);
/**
* \brief Setter for the acknowledge number.
*
* \param new_ack_seq uint32_t with the new acknowledge number.
* \param new_ack_seq The new acknowledge number.
*/
void ack_seq(uint32_t new_ack_seq);
/**
* \brief Setter for the window size.
*
* \param new_window uint16_t with the new window size.
* \param new_window The new window size.
*/
void window(uint16_t new_window);
/**
* \brief Setter for the checksum field.
*
* \param new_check uint16_t with the new checksum.
* \param new_check The new checksum.
*/
void check(uint16_t new_check);
/**
* \brief Setter for the urgent pointer field.
*
* \param new_urg_ptr uint16_t with the new urgent pointer.
* \param new_urg_ptr The new urgent pointer.
*/
void urg_ptr(uint16_t new_urg_ptr);
/**
* \brief Setter for the data offset pointer field.
*
* \param new_doff uint8_t with the new data offset pointer.
* \param new_doff The new data offset pointer.
*/
void data_offset(uint8_t new_doff);
@@ -234,34 +267,34 @@ namespace Tins {
/**
* \brief Set the maximum segment size.
*
* \param value uint16_t with the new maximum segment size.
* \param value The new maximum segment size.
*/
void set_mss(uint16_t value);
/**
* \brief Set the timestamp.
*
* \param value uint32_t with the current value of the timestamp clock.
* \param reply uint32_t with the echo reply field.
* \param value The current value of the timestamp clock.
* \param reply The echo reply field.
*/
void set_timestamp(uint32_t value, uint32_t reply);
/**
* \brief Set a TCP flag value.
*
* \param tcp_flag Flag which indicates the flag to be set.
* \param value uint8_t with the new value for this flag. Must be 0 or 1.
* \param tcp_flag The flag to be set.
* \param value The new value for this flag. Must be 0 or 1.
*/
void set_flag(Flags tcp_flag, uint8_t value);
/**
* \brief Adds a TCP option.
*
* \param tcp_option Options indicating the option to be set.
* \param length uint8_t with the length of this option(optional).
* \param data uint8_t* containing this option's data(optional).
* \param tcp_option The option type flag to be set.
* \param length The length of this option(optional).
* \param data Pointer to this option's data(optional).
*/
void add_option(Options tcp_option, uint8_t length = 0, uint8_t *data = 0);
void add_option(Options tcp_option, uint8_t length = 0, const uint8_t *data = 0);
/**
* \brief Returns the header size.
@@ -316,16 +349,6 @@ namespace Tins {
uint16_t urg_ptr;
} __attribute__((packed));
struct TCPOption {
TCPOption(uint8_t okind, uint8_t olength, uint8_t *odata) :
kind(okind), length(olength), data(odata) { }
uint8_t *write(uint8_t *buffer);
uint8_t kind, length;
uint8_t *data;
};
static const uint16_t DEFAULT_WINDOW;
/** \brief Serialices this TCP PDU.
@@ -336,7 +359,7 @@ namespace Tins {
void write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU *parent);
tcphdr _tcp;
std::vector<TCPOption> _options;
std::list<TCPOption> _options;
uint32_t _options_size, _total_options_size;
};
};

22
src/dhcp.cpp
View File

@@ -40,20 +40,26 @@ Tins::DHCP::DHCP() : _size(sizeof(uint32_t) + 1) {
Tins::DHCP::DHCP(const uint8_t *buffer, uint32_t total_sz) : BootP(buffer, total_sz, 0) {
buffer += BootP::header_size();
total_sz -= BootP::header_size();
uint8_t args[2];
uint8_t args[2] = {0};
while(total_sz) {
for(unsigned i(0); i < 2; ++i) {
for(unsigned i(0); i < 2 && args[0] != END; ++i) {
args[i] = *(buffer++);
total_sz--;
if(!total_sz)
throw std::runtime_error("Not enought size for a DHCP header in the buffer.");
}
// Not enough size for this option
if(total_sz < args[1])
throw std::runtime_error("Not enought size for a DHCP header in the buffer.");
add_option((Options)args[0], args[1], buffer);
buffer += args[1];
total_sz -= args[1];
// If the END-OF-OPTIONS was not found...
if(args[0] != END) {
// Not enough size for this option
if(total_sz < args[1])
throw std::runtime_error("Not enought size for a DHCP header in the buffer.");
add_option((Options)args[0], args[1], buffer);
buffer += args[1];
total_sz -= args[1];
}
// Otherwise, break the loop.
else
total_sz = 0;
}
}

47
src/tcp.cpp
View File

@@ -47,16 +47,47 @@ Tins::TCP::TCP(const uint8_t *buffer, uint32_t total_sz) : PDU(IPPROTO_TCP) {
throw std::runtime_error("Not enought size for an TCP header in the buffer.");
std::memcpy(&_tcp, buffer, sizeof(tcphdr));
/* Options... */
buffer += sizeof(tcphdr);
total_sz -= sizeof(tcphdr);
uint32_t index = 0, header_end = (data_offset() * sizeof(uint32_t)) - sizeof(tcphdr);
if(total_sz >= header_end) {
uint8_t args[2] = {0};
while(index < header_end) {
for(unsigned i(0); i < 2 && args[0] != NOP; ++i) {
args[i] = buffer[index++];
if(index == header_end)
throw std::runtime_error("Not enought size for a TCP header in the buffer.");
}
// We don't want to store NOPs and EOLs
if(args[0] != NOP && args[0] != EOL) {
if(args[1]) {
// Not enough size for this option
if(header_end - index < args[1] - (sizeof(uint8_t) << 1)) {
throw std::runtime_error("Not enought size for a TCP header in the buffer.");
}
args[1] -= (sizeof(uint8_t) << 1);
add_option((Options)args[0], args[1], buffer + index);
}
index += args[1];
}
else if(args[0] == EOL)
index = header_end;
else // Skip the NOP
args[0] = 0;
}
buffer += index;
total_sz -= index;
_total_options_size = header_end;
_options_size = (_total_options_size / 4) * 4;
}
if(total_sz)
inner_pdu(new RawPDU(buffer + sizeof(tcphdr), total_sz));
inner_pdu(new RawPDU(buffer, total_sz));
}
Tins::TCP::~TCP() {
for(unsigned i(0); i < _options.size(); ++i)
delete[] _options[i].data;
for(std::list<TCPOption>::iterator it = _options.begin(); it != _options.end(); ++it)
delete[] it->data;
}
void Tins::TCP::dport(uint16_t new_dport) {
@@ -166,7 +197,7 @@ void Tins::TCP::set_flag(Flags tcp_flag, uint8_t value) {
};
}
void Tins::TCP::add_option(Options tcp_option, uint8_t length, uint8_t *data) {
void Tins::TCP::add_option(Options tcp_option, uint8_t length, const 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));
@@ -184,8 +215,8 @@ void Tins::TCP::write_serialization(uint8_t *buffer, uint32_t total_sz, const PD
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);
for(std::list<TCPOption>::iterator it = _options.begin(); it != _options.end(); ++it)
buffer = it->write(buffer);
if(_options_size < _total_options_size) {
uint8_t padding = _total_options_size;