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75546fcf6c
RIOT/sys/net/transport_layer/destiny/tcp.c
Cenk Gündoğan 75546fcf6c destiny: set ack bit for (almost) all segments after syn 
The current implementation does not set the ack bit
for outgoing data segments and the fin segment.

However, RFC793 states that all segments
should have an ack bit set in order to present a valid
ack nr. in outgoing segments.

Currently, data segments and acknowledgement segments
are distinguished by the existence of their ack bit.
With the new assumption, that both of these types of
segments need an ack bit set, I had to change several
parts of the current implementation to make this
decision by inspecting the payload size.

destiny: added parens
2014-06-24 10:44:11 +02:00

412 lines
14 KiB
C
Raw Blame History

/**
* Destiny TCP implementation
*
* Copyright (C) 2013 INRIA.
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License. See the file LICENSE in the top level directory for more
* details.
*
* @ingroup destiny
* @{
* @file tcp.c
* @brief TCP implementation
* @author Oliver Gesch <oliver.gesch@googlemail.com>
* @}
*/
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "sixlowpan.h"
#include "thread.h"
#include "vtimer.h"
#include "destiny/in.h"
#include "net_help.h"
#include "msg_help.h"
#include "socket.h"
#include "tcp_hc.h"
#include "tcp_timer.h"
#include "tcp.h"
#ifdef TCP_HC
mutex_t global_context_counter_mutex;
uint8_t global_context_counter;
#endif
mutex_t global_sequence_counter_mutex;
uint32_t global_sequence_counter;
void printTCPHeader(tcp_hdr_t *tcp_header)
{
printf("\nBEGIN: TCP HEADER\n");
printf("ack_nr: %" PRIu32 "\n", tcp_header->ack_nr);
printf("checksum: %i\n", tcp_header->checksum);
printf("dataOffset_reserved: %i\n", tcp_header->dataOffset_reserved);
printf("dst_port: %i\n", tcp_header->dst_port);
printf("reserved_flags: %i\n", tcp_header->reserved_flags);
printf("seq_nr: %" PRIu32 "\n", tcp_header->seq_nr);
printf("src_port: %i\n", tcp_header->src_port);
printf("urg_pointer: %i\n", tcp_header->urg_pointer);
printf("window: %i\n", tcp_header->window);
printf("END: TCP HEADER\n");
}
void printArrayRange_tcp(uint8_t *udp_header, uint16_t len)
{
int i = 0;
printf("-------------MEMORY-------------\n");
for (i = 0; i < len; i++) {
printf("%#x ", *(udp_header + i));
}
printf("-------------MEMORY-------------\n");
}
uint16_t tcp_csum(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header)
{
uint16_t sum;
uint16_t len = NTOHS(ipv6_header->length);
sum = len + IPPROTO_TCP;
sum = csum(sum, (uint8_t *)&ipv6_header->srcaddr, 2 * sizeof(ipv6_addr_t));
sum = csum(sum, (uint8_t *)tcp_header, len);
return (sum == 0) ? 0xffff : HTONS(sum);
}
uint8_t handle_payload(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header,
socket_internal_t *tcp_socket, uint8_t *payload)
{
(void) tcp_header;
msg_t m_send_tcp, m_recv_tcp;
uint8_t tcp_payload_len = NTOHS(ipv6_header->length) - TCP_HDR_LEN;
uint8_t acknowledged_bytes = 0;
if (tcp_payload_len > tcp_socket->socket_values.tcp_control.rcv_wnd) {
mutex_lock(&tcp_socket->tcp_buffer_mutex);
memcpy(tcp_socket->tcp_input_buffer, payload,
tcp_socket->socket_values.tcp_control.rcv_wnd);
acknowledged_bytes = tcp_socket->socket_values.tcp_control.rcv_wnd;
tcp_socket->socket_values.tcp_control.rcv_wnd = 0;
tcp_socket->tcp_input_buffer_end = tcp_socket->tcp_input_buffer_end +
tcp_socket->socket_values.tcp_control.rcv_wnd;
mutex_unlock(&tcp_socket->tcp_buffer_mutex);
}
else {
mutex_lock(&tcp_socket->tcp_buffer_mutex);
memcpy(tcp_socket->tcp_input_buffer, payload, tcp_payload_len);
tcp_socket->socket_values.tcp_control.rcv_wnd =
tcp_socket->socket_values.tcp_control.rcv_wnd - tcp_payload_len;
acknowledged_bytes = tcp_payload_len;
tcp_socket->tcp_input_buffer_end = tcp_socket->tcp_input_buffer_end +
tcp_payload_len;
mutex_unlock(&tcp_socket->tcp_buffer_mutex);
}
if (thread_getstatus(tcp_socket->recv_pid) == STATUS_RECEIVE_BLOCKED) {
net_msg_send_recv(&m_send_tcp, &m_recv_tcp, tcp_socket->recv_pid, UNDEFINED);
}
return acknowledged_bytes;
}
void handle_tcp_ack_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header,
socket_internal_t *tcp_socket)
{
msg_t m_recv_tcp, m_send_tcp;
uint8_t target_pid;
if (tcp_socket->socket_values.tcp_control.state == TCP_LAST_ACK) {
target_pid = tcp_socket->recv_pid;
close_socket(tcp_socket);
msg_send(&m_send_tcp, target_pid, 0);
return;
}
else if (tcp_socket->socket_values.tcp_control.state == TCP_CLOSING) {
msg_send(&m_send_tcp, tcp_socket->recv_pid, 0);
msg_send(&m_send_tcp, tcp_socket->send_pid, 0);
return;
}
else if (get_waiting_connection_socket(tcp_socket->socket_id, ipv6_header,
tcp_header) != NULL) {
m_send_tcp.content.ptr = (char *)tcp_header;
net_msg_send_recv(&m_send_tcp, &m_recv_tcp, tcp_socket->recv_pid, TCP_ACK);
return;
}
else if (tcp_socket->socket_values.tcp_control.state == TCP_ESTABLISHED) {
if (check_tcp_consistency(&tcp_socket->socket_values, tcp_header, 0) == PACKET_OK) {
m_send_tcp.content.ptr = (char *)tcp_header;
net_msg_send(&m_send_tcp, tcp_socket->send_pid, 0, TCP_ACK);
return;
}
}
printf("NO WAY OF HANDLING THIS ACK!\n");
}
void handle_tcp_rst_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header,
socket_internal_t *tcp_socket)
{
(void) ipv6_header;
(void) tcp_header;
(void) tcp_socket;
/* TODO: Reset connection */
}
void handle_tcp_syn_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header,
socket_internal_t *tcp_socket)
{
msg_t m_send_tcp;
if (tcp_socket->socket_values.tcp_control.state == TCP_LISTEN) {
socket_internal_t *new_socket = new_tcp_queued_socket(ipv6_header,
tcp_header);
if (new_socket != NULL) {
#ifdef TCP_HC
update_tcp_hc_context(true, new_socket, tcp_header);
#endif
/* notify socket function destiny_socket_accept(..) that a new
* connection request has arrived. No need to wait for an answer
* because the server destiny_socket_accept() function isnt reading
* from anything other than the queued sockets */
net_msg_send(&m_send_tcp, tcp_socket->recv_pid, 0, TCP_SYN);
}
else {
printf("Dropped TCP SYN Message because an error occured while "\
"requesting a new queued socket!\n");
}
}
else {
printf("Dropped TCP SYN Message because socket was not in state TCP_LISTEN!");
}
}
void handle_tcp_syn_ack_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header,
socket_internal_t *tcp_socket)
{
(void) ipv6_header;
msg_t m_send_tcp;
if (tcp_socket->socket_values.tcp_control.state == TCP_SYN_SENT) {
m_send_tcp.content.ptr = (char *) tcp_header;
net_msg_send(&m_send_tcp, tcp_socket->recv_pid, 0, TCP_SYN_ACK);
}
else {
printf("Socket not in state TCP_SYN_SENT, dropping SYN-ACK-packet!");
}
}
void handle_tcp_fin_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header,
socket_internal_t *tcp_socket)
{
(void) ipv6_header;
msg_t m_send;
socket_t *current_tcp_socket = &tcp_socket->socket_values;
uint8_t send_buffer[BUFFER_SIZE];
ipv6_hdr_t *temp_ipv6_header = ((ipv6_hdr_t *)(&send_buffer));
tcp_hdr_t *current_tcp_packet = ((tcp_hdr_t *)(&send_buffer[IPV6_HDR_LEN]));
set_tcp_cb(&current_tcp_socket->tcp_control, tcp_header->seq_nr + 1,
current_tcp_socket->tcp_control.send_wnd, tcp_header->ack_nr + 1,
tcp_header->ack_nr, tcp_header->window);
#ifdef TCP_HC
current_tcp_socket->tcp_control.tcp_context.hc_type = COMPRESSED_HEADER;
#endif
if (current_tcp_socket->tcp_control.state == TCP_FIN_WAIT_1) {
current_tcp_socket->tcp_control.state = TCP_CLOSING;
send_tcp(tcp_socket, current_tcp_packet, temp_ipv6_header, TCP_FIN_ACK, 0);
}
else {
current_tcp_socket->tcp_control.state = TCP_LAST_ACK;
send_tcp(tcp_socket, current_tcp_packet, temp_ipv6_header, TCP_FIN_ACK, 0);
}
net_msg_send(&m_send, tcp_socket->recv_pid, 0, CLOSE_CONN);
}
void handle_tcp_fin_ack_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header,
socket_internal_t *tcp_socket)
{
(void) ipv6_header;
msg_t m_send;
socket_t *current_tcp_socket = &tcp_socket->socket_values;
uint8_t send_buffer[BUFFER_SIZE];
ipv6_hdr_t *temp_ipv6_header = ((ipv6_hdr_t *)(&send_buffer));
tcp_hdr_t *current_tcp_packet = ((tcp_hdr_t *)(&send_buffer[IPV6_HDR_LEN]));
current_tcp_socket->tcp_control.state = TCP_CLOSED;
set_tcp_cb(&current_tcp_socket->tcp_control, tcp_header->seq_nr + 1,
current_tcp_socket->tcp_control.send_wnd, tcp_header->ack_nr,
tcp_header->ack_nr, tcp_header->window);
#ifdef TCP_HC
current_tcp_socket->tcp_control.tcp_context.hc_type = COMPRESSED_HEADER;
#endif
send_tcp(tcp_socket, current_tcp_packet, temp_ipv6_header, TCP_ACK, 0);
msg_send(&m_send, tcp_socket->send_pid, 0);
msg_send(&m_send, tcp_socket->recv_pid, 0);
}
void handle_tcp_no_flags_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header,
socket_internal_t *tcp_socket, uint8_t *payload, uint8_t tcp_payload_len)
{
uint8_t read_bytes = 0;
socket_t *current_tcp_socket = &tcp_socket->socket_values;
uint8_t send_buffer[BUFFER_SIZE];
ipv6_hdr_t *temp_ipv6_header = ((ipv6_hdr_t *)(&send_buffer));
tcp_hdr_t *current_tcp_packet = ((tcp_hdr_t *)(&send_buffer[IPV6_HDR_LEN]));
if (check_tcp_consistency(current_tcp_socket, tcp_header, tcp_payload_len) == PACKET_OK) {
read_bytes = handle_payload(ipv6_header, tcp_header, tcp_socket, payload);
/* Refresh TCP status values */
current_tcp_socket->tcp_control.state = TCP_ESTABLISHED;
set_tcp_cb(&current_tcp_socket->tcp_control,
tcp_header->seq_nr + read_bytes,
current_tcp_socket->tcp_control.rcv_wnd,
current_tcp_socket->tcp_control.send_nxt,
current_tcp_socket->tcp_control.send_una,
current_tcp_socket->tcp_control.send_wnd);
/* Send packet */
// block_continue_thread();
#ifdef TCP_HC
current_tcp_socket->tcp_control.tcp_context.hc_type = COMPRESSED_HEADER;
#endif
send_tcp(tcp_socket, current_tcp_packet, temp_ipv6_header, TCP_ACK, 0);
}
/* ACK packet probably got lost */
else {
// block_continue_thread();
#ifdef TCP_HC
current_tcp_socket->tcp_control.tcp_context.hc_type = FULL_HEADER;
#endif
send_tcp(tcp_socket, current_tcp_packet, temp_ipv6_header, TCP_ACK, 0);
}
}
void tcp_packet_handler(void)
{
msg_t m_recv_ip, m_send_ip;
ipv6_hdr_t *ipv6_header;
tcp_hdr_t *tcp_header;
uint8_t *payload;
socket_internal_t *tcp_socket = NULL;
uint16_t chksum;
while (1) {
msg_receive(&m_recv_ip);
ipv6_header = ((ipv6_hdr_t *)m_recv_ip.content.ptr);
tcp_header = ((tcp_hdr_t *)(m_recv_ip.content.ptr + IPV6_HDR_LEN));
#ifdef TCP_HC
tcp_socket = decompress_tcp_packet(ipv6_header);
#else
switch_tcp_packet_byte_order(tcp_header);
tcp_socket = get_tcp_socket(ipv6_header, tcp_header);
#endif
chksum = tcp_csum(ipv6_header, tcp_header);
payload = (uint8_t *)(m_recv_ip.content.ptr + IPV6_HDR_LEN +
tcp_header->dataOffset_reserved * 4);
if ((chksum == 0xffff) && (tcp_socket != NULL)) {
#ifdef TCP_HC
update_tcp_hc_context(true, tcp_socket, tcp_header);
#endif
/* Remove reserved bits from tcp flags field */
uint8_t tcp_flags = tcp_header->reserved_flags & REMOVE_RESERVED;
switch (tcp_flags) {
case TCP_ACK: {
/* only ACK Bit set */
uint8_t tcp_payload_len = NTOHS(ipv6_header->length) - TCP_HDR_LEN;
uint8_t state = tcp_socket->socket_values.tcp_control.state;
if ((tcp_payload_len > 0) && (state == TCP_ESTABLISHED)) {
/* handle data segments only when the connection was established successfully */
handle_tcp_no_flags_packet(ipv6_header, tcp_header, tcp_socket, payload, tcp_payload_len);
}
else if (tcp_payload_len == 0
&& (state == TCP_ESTABLISHED || state == TCP_SYN_RCVD
|| state == TCP_CLOSING || state == TCP_LAST_ACK)) {
/* no payload, acknowledging data only */
handle_tcp_ack_packet(ipv6_header, tcp_header, tcp_socket);
}
break;
}
case TCP_RST: {
printf("RST Bit set!\n");
/* only RST Bit set */
handle_tcp_rst_packet(ipv6_header, tcp_header, tcp_socket);
break;
}
case TCP_SYN: {
/* only SYN Bit set, look for matching, listening socket
* and request new queued socket */
printf("SYN Bit set!\n");
handle_tcp_syn_packet(ipv6_header, tcp_header, tcp_socket);
break;
}
case TCP_SYN_ACK: {
/* only SYN and ACK Bit set, complete three way handshake
* when socket in state TCP_SYN_SENT */
handle_tcp_syn_ack_packet(ipv6_header, tcp_header, tcp_socket);
break;
}
case TCP_FIN_ACK: {
if (tcp_socket->socket_values.tcp_control.state == TCP_ESTABLISHED) {
/* this is the first FIN */
printf("FIN ACK Bit set!\n");
handle_tcp_fin_packet(ipv6_header, tcp_header, tcp_socket);
}
else {
/* this is the response to FIN */
handle_tcp_fin_ack_packet(ipv6_header, tcp_header, tcp_socket);
}
break;
}
default: {
printf("Unable to process the incoming segment!\n");
}
}
}
else {
printf("Wrong checksum (%x) or no corresponding socket found!\n",
chksum);
printArrayRange(((uint8_t *)ipv6_header), IPV6_HDR_LEN +
NTOHS(ipv6_header->length), "Incoming");
print_tcp_status(INC_PACKET, ipv6_header, tcp_header,
&tcp_socket->socket_values);
}
msg_reply(&m_recv_ip, &m_send_ip);
}
}
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