/*
* sleep with timeout in milliseconds. Need to disable interrupts during method call as we
are not using semaphore for sleeping minithreads.
*/
void minithread_sleep_with_timeout(int delay) {
interrupt_level_t old_level = set_interrupt_level(DISABLED);
minithread_t* current_thread = schedule_data->running_thread;
register_alarm(delay, wakeup_thread, (void *) current_thread); //registers alarm
minithread_stop(); //moves to next thread
set_interrupt_level(old_level);
}
/*
* Find path to the destination. Return a pointer to a miniroute_path struct,
* or NULL if no route can be found.
*/
static miniroute_path_t
miniroute_discover_path(network_address_t dest)
{
miniroute_path_t path = NULL;
struct routing_header routing_hdr;
miniroute_disc_hist_t disc;
miniroute_pack_discovery_hdr(&routing_hdr, dest);
disc = miniroute_dischist_from_hdr(&routing_hdr);
miniroute_cache_put_item(disc_cache, disc);
#if MINIROUTE_CACHE_DEBUG == 1
printf("Broadcasting discovery packet with header: \n");
miniroute_print_hdr(&routing_hdr);
#endif
network_bcast_pkt(MINIROUTE_HDRSIZE, (char*)&routing_hdr, 0, NULL);
discovery_alarm = register_alarm(12000, semaphore_Signal, discovery_sig);
semaphore_P(discovery_sig);
/* Success when alarm is disabled by receiving a reply */
if (-1 == discovery_alarm) {
path = discovered_path;
discovered_path = NULL;
}
return path;
}
/*
* sleep with timeout in milliseconds
*/
void minithread_sleep_with_timeout(int delay)
{
// Create the sleep semaphore
semaphore_t sleep_sem = semaphore_create();
interrupt_level_t prev_level; // ISO C90...
// Initialize it to a value of 0 so it can act as a way to signal threads
semaphore_initialize(sleep_sem, 0);
// Disable interrupts
prev_level = set_interrupt_level(DISABLED);
// Register the alarm
register_alarm(delay, &minithread_sleep_alarm_wakeup, sleep_sem);
// If, at this point, interrupts were enabled, we could context switch away
// the alarm could be triggered afterwards before the semaphore_P below was
// called (depending on this threads priority level, etc) and then when this
// thread finally calls semaphore_P(), it will hang forever.
// Therefore we have interrupts disabled.
// Wait on the sleep semaphore
semaphore_P(sleep_sem);
// Now that we've awoken, free the sleep semaphore
semaphore_destroy(sleep_sem);
// Restore the previous interrupt level
set_interrupt_level(prev_level); // is this necessary?
}
/*
* sleep with timeout in milliseconds
*/
void
minithread_sleep_with_timeout(int delay)
{
interrupt_level_t l = set_interrupt_level(DISABLED);
register_alarm(delay, get_new_alarm_handler(), minithread_self());
set_interrupt_level(l);
minithread_stop();
}
//Supposed to be run in the background
void delete_sockets(void *arg) {
minisocket_t socket;
semaphore_P(delete_semaphore);
queue_dequeue(sockets_to_delete, (void**) &socket);
register_alarm(15000, &delete_socket, (void*) socket);
semaphore_V(delete_semaphore);
}
int wait_for_arrival_or_timeout(semaphore_t sema, alarm_t* alarm, int timeout) {
if (sema == NULL) {
fprintf(stderr, "ERROR: wait_for_arrival_or_timeout() passed uninitialized semaphore\n");
return -1;
}
*alarm = (alarm_t) register_alarm(timeout, (alarm_handler_t) semaphore_V, (void*) sema);
semaphore_P(sema);
// fprintf(stderr, "Woke up!\n");
if (*alarm != NULL) {
return deregister_alarm((alarm_id) (*alarm));
} else {
return 0;
}
}
/* Prune entries older than 3 seconds from the route cache */
void prune_route_cache(void* arg)
{
// This will store the next item in the linked list of hashmap entries
hashmap_item_t next_item;
// This will store a pointer to the route data struct
route_data_t route_data;
hashmap_item_t item;
// Get the first item in the hashmap (first in the chronological sense)
semaphore_P(route_cache_sem);
item = hashmap_get_first(route_cache);
// Go through all the items until we arrive at one that isn't ready for deletion
while (item != NULL)
{
// Get the next item ahead of time, in case we delete this item
next_item = hashmap_get_next(item);
// Get the value of the hashmap, which is a route_data struct
route_data = (route_data_t) hashmap_item_get_value(item);
// Check if the entry is more than 3 seconds old
if ((ticks - route_data->time_found) * PERIOD/MILLISECOND > 3000)
{
//printf("Deleting key %d\n", hashmap_item_get_key(item));
// Delete the route data struct
delete_route_data(route_data);
// Run hashmap delete, which will delete the hashmap_item struct (i.e. "item")
hashmap_delete(route_cache, hashmap_item_get_key(item));
}
else
{
// If the entry wasn't ready for deletion, then we can end (since the
// linked list is maintained in chronological order of insertion)
break;
}
// If we deleted the item, move to the next one
item = next_item;
}
semaphore_V(route_cache_sem);
// Once we're done, register the alarm to run again in 3 seconds
register_alarm(3000, &prune_route_cache, NULL);
}
/* Performs any initialization of the miniroute layer, if required. */
void miniroute_initialize()
{
int i;
// Cache routes to hosts we've already found - it's of a static size
route_cache = hashmap_create(SIZE_OF_ROUTE_CACHE, 0);
// Cache the ID of the last discovery request we've seen from each host
discovery_packets_seen = hashmap_create(10, 1);
// The current discovery requests that are running
current_discovery_requests = hashmap_create(10, 1);
// The starting ID for discovery requests emanating from this host
route_request_id = 0;
// Setup a semaphore to control access to the route cache
// also used to ensure the cache cleanup thread doesn't delete a route while
// we're using it
route_cache_sem = semaphore_create();
semaphore_initialize(route_cache_sem, 1);
// Create a semaphore to control access to the request ID variable
request_id_sem = semaphore_create();
semaphore_initialize(request_id_sem, 1);
// Create a malloc'd chunk of route_req_seen structs to store info on
// route requests we've recently seen
route_reqs_seen = (route_req_seen_t*) malloc(sizeof(route_req_seen_t) * ROUTE_REQS_TO_STORE);
for (i = 0; i < ROUTE_REQS_TO_STORE; i++)
{
route_reqs_seen[i] = (route_req_seen_t) malloc(sizeof(struct route_req_seen));
route_reqs_seen[i]->in_use = 0; // used to indicate this isn't in use
}
route_reqs_idx = 0;
// Register an alarm to prune the route cache every 3 seconds
register_alarm(3000, &prune_route_cache, NULL);
}
void minisocket_close(minisocket_t *socket)
{
if (socket) {
if (socket->socket_state == CLOSING) {
socket->socket_state = WAITING_SYN;
return;
}
if (socket->socket_state == CLOSED) {
minisocket_free(socket);
return;
}
minisocket_error s_error;
int wait_val = 100;
while (wait_val <= 12800) {
send_control_message(MSG_FIN, socket->remote_port, socket->remote_addr,
socket->local_port, socket->seq_number, socket->ack_number, &s_error);
socket->seq_number += 1;
if (s_error == SOCKET_OUTOFMEMORY) {
return;
}
alarm_id a = register_alarm(wait_val, (alarm_handler_t) semaphore_V, socket->wait_for_ack);
semaphore_P(socket->wait_for_ack);
interrupt_level_t old_level = set_interrupt_level(DISABLED);
if (socket->ack_flag == 0) {
wait_val *= 2;
socket->seq_number--;
set_interrupt_level(old_level);
continue;
}
else if (socket->ack_flag == 1) {
deregister_alarm(a);
minisocket_free(socket);
set_interrupt_level(old_level);
return;
}
}
}
semaphore_V(socket->send_receive_mutex);
}
void delete_sockets(void* arg)
{
// This is a background thread, because we can't register alarms in the IH as
// it uses malloc, which is very inefficient...
minisocket_t socket;
interrupt_level_t prev_level;
while (1)
{
// Both of the below data structures are accessed by the IH, so we must
// disable interrupts
prev_level = set_interrupt_level(DISABLED);
semaphore_P(socket_needs_delete);
queue_dequeue(sockets_to_delete, (void**) &socket);
set_interrupt_level(prev_level);
register_alarm(15000, &delete_socket, (void*) socket);
//minisocket_destroy(socket, 0);
}
}
//Transmit a packet and handle retransmission attempts
int transmit_packet(minisocket_t socket, network_address_t dst_addr, int dst_port,
short incr_seq, char message_type, int data_len, char* data,
minisocket_error* error)
{
mini_header_reliable_t newReliableHeader;
void *alarmId;
int sendSucessful;
network_address_t my_addr;
int success = 0;
int connected = 0;
if (message_type == MSG_ACK)
connected = 1;
network_get_my_address(my_addr);
if (socket == NULL)
{
*error = SOCKET_INVALIDPARAMS;
return -1;
}
if (socket->status == TCP_PORT_CLOSING)
{
*error = SOCKET_SENDERROR;
return -1;
}
newReliableHeader = create_reliable_header(my_addr, socket->port_number, dst_addr,
dst_port, message_type, socket->seq_number, socket->ack_number);
socket->timeout = 100;
while(socket->timeout <= 6400)
{
printf("sending packet to %d, seq=%d, ack=%d, type=%d\n", dst_port, socket->seq_number, socket->ack_number, message_type);
sendSucessful = network_send_pkt(dst_addr, sizeof(struct mini_header_reliable),
(char*) newReliableHeader, data_len, (char*) data);
if (sendSucessful == -1)
{
socket->timeout *= 2;
continue;
}
alarmId = register_alarm(socket->timeout, &wake_up_semaphore, socket);
if (message_type == MSG_SYN)
{
socket->waiting = TCP_PORT_WAITING_SYNACK;
semaphore_P(socket->wait_for_ack_semaphore);
}
else if (!connected)
{
socket->waiting = TCP_PORT_WAITING_ACK;
semaphore_P(socket->wait_for_ack_semaphore);
}
else {
socket->waiting = TCP_PORT_WAITING_NONE;
}
semaphore_P(socket->mutex);
if (socket->waiting == TCP_PORT_WAITING_NONE)
{
/* I think incr_seq belongs before the _P on wait_for_ack, but that breaks it for now :/
if (incr_seq)
{
semaphore_P(socket->mutex);
socket->seq_number++;
semaphore_V(socket->mutex);
}
*/ if (message_type == MSG_SYN)
{
//we got a synack back, so we need to make sure to send an ack to the server
newReliableHeader = create_reliable_header(my_addr, socket->port_number, dst_addr,
dst_port, MSG_ACK, socket->seq_number, socket->ack_number);
socket->timeout = 100;
message_type = MSG_ACK;
connected = 1;
semaphore_V(socket->mutex);
continue;
}
deregister_alarm(alarmId);
success = 1;
semaphore_V(socket->mutex);
break;
}
else
{
if (socket->status == TCP_PORT_UNABLE_TO_CONNECT)
{
deregister_alarm(alarmId);
success = 0;
semaphore_V(socket->mutex);
break;
}
socket->timeout *= 2;
semaphore_V(socket->mutex);
}
}
semaphore_P(socket->mutex);
socket->timeout = 100;
if (success == 0)
{
socket->waiting = TCP_PORT_WAITING_NONE;
*error = SOCKET_NOSERVER;
}
semaphore_V(socket->mutex);
*error = SOCKET_NOERROR;
free(newReliableHeader);
return 0;
}
void minisocket_close(minisocket_t *socket) {
if (socket == NULL || mini_socket_data[socket->local_port_number] == NULL || socket->state == CLOSED) {
return; // no cleanup necessary
}
fprintf(stderr, "Closing time \n");
mini_header_reliable_t header;
minisocket_create_reliable_header((mini_header_reliable_t *) &header, socket, socket->remote_port_number, socket->remote_address, MSG_FIN);
int send_success = 0;
int timeout = START_TIMEOUT / 2;
for (int i = 0; i < MAX_FAILURES; i++) {
if (socket->state == CLOSED) {
return; //received a MSG_FIN message in network_handler, so stop re-tries
}
timeout = timeout * 2;
network_send_pkt(socket->remote_address, sizeof(mini_header_reliable_t), (char *) &header, 0, empty_message);
alarm_id timeout_alarm_id = register_alarm(timeout, handshake_timeout_handler, (void *) socket->ack_ready);
int alarm_fired = 0;
//keep looking through received packets until either the alarm fires or it finds the correct packet
while (!send_success && !alarm_fired) {
semaphore_P(socket->ack_ready);
//alarm has fired, since there are no packets to be received
if (queue_length(socket->acknowledgements) == 0) {
printf("CLOSE queue length: %d\n", queue_length(socket->acknowledgements));
alarm_fired = 1; //goes to next iteration of for loop
}
//There is a packet (alarm hasnt fired yet)
else {
network_interrupt_arg_t* interrupt_message = NULL;
interrupt_level_t old_level = set_interrupt_level(DISABLED);
queue_dequeue(socket->acknowledgements, (void **) &interrupt_message);
set_interrupt_level(old_level);
// verify non null message
if (interrupt_message != NULL) {
mini_header_reliable_t* received_header = (mini_header_reliable_t *) interrupt_message->buffer;
//already checked port and address in network_handler
if (received_header->message_type == MSG_ACK) {
deregister_alarm(timeout_alarm_id); //only deregister alarm when the right packet is found
send_success = 1;
free(interrupt_message);
break;
}
else {
free(interrupt_message);
}
}
}
}
if (send_success) {
break;
}
}
printf("out of CLOSE\n");
//sender considers the connection closed, even if MSG_ACK not received
if (socket->state != CLOSED) {
printf("calling DESTROY from CLOSE\n");
minisocket_destroy(socket);
}
}
int minisocket_send(minisocket_t *socket, const char *msg, int len, minisocket_error *error) {
//Check params
if (socket == NULL || mini_socket_data[socket->local_port_number] != socket || len < 0 || msg == NULL) {
*error = SOCKET_INVALIDPARAMS;
return -1;
}
if (socket->state == CLOSED) {
*error = SOCKET_SENDERROR;
return -1;
}
if (len == 0) {
return 0;
}
//can't send more bytes than we have
if (len > strlen(msg)) {
len = strlen(msg);
}
int bytes_sent = 0;
int max_data_size = MAX_NETWORK_PKT_SIZE - sizeof(mini_header_reliable_t);
int data_left = len;
int packet_size;
mini_header_reliable_t header;
minisocket_create_reliable_header((mini_header_reliable_t *) &header, socket, socket->remote_port_number, socket->remote_address, MSG_ACK);
//Keep sending until all is sent
while (data_left != 0) {
if (data_left >= max_data_size) {
packet_size = max_data_size;
}
else {
packet_size = data_left;
}
data_left -= packet_size;
pack_unsigned_int(header.seq_number, socket->seq);
int send_success = 0;
//Attempt to send message
int timeout = START_TIMEOUT/2;
for (int i = 0; i < MAX_FAILURES; i++) {
//printf("i: %d\n", i);
timeout = timeout * 2;
//update the seq and ack numbers for the header from the socket
//printf("seq: %u, ack: %u\n", socket->seq, socket->ack);
pack_unsigned_int(header.ack_number, socket->ack);
pack_unsigned_int(header.seq_number, socket->seq);
network_send_pkt(socket->remote_address, sizeof(mini_header_reliable_t), (char *) &header, packet_size, (char *) msg);
alarm_id timeout_alarm_id = register_alarm(timeout, handshake_timeout_handler, (void *) socket->ack_ready);
int alarm_fired = 0;
//keep looking through received packets until either the alarm fires or it finds the correct packet
while (!send_success && !alarm_fired) {
semaphore_P(socket->ack_ready);
if (queue_length(socket->acknowledgements) == 0) {
// printf("no message in queue\n");
alarm_fired = 1; //goes to next iteration of for loop
}
else {
// printf("length of queue currently %d\n", queue_length(socket->acknowledgements));
network_interrupt_arg_t* interrupt_message = NULL;
interrupt_level_t old_level = set_interrupt_level(DISABLED);
queue_dequeue(socket->acknowledgements, (void **) &interrupt_message);
set_interrupt_level(old_level);
if (interrupt_message != NULL) {
mini_header_reliable_t* received_header = (mini_header_reliable_t *) interrupt_message->buffer;
network_address_t temp_address;
unpack_address(received_header->source_address, temp_address);
unsigned int new_ack = unpack_unsigned_int(received_header->ack_number);
//printf("Received an acknowledgment with ack number %u \n", new_ack);
if (socket->remote_port_number == unpack_unsigned_short(received_header->source_port) &&
network_compare_network_addresses(socket->remote_address, temp_address) != 0 &&
received_header->message_type == MSG_ACK && new_ack == (socket->seq + packet_size)) {
//same address, same ports, right message, right ack
deregister_alarm(timeout_alarm_id); //only deregister alarm when the right packet is found
send_success = 1;
bytes_sent += packet_size;
msg += packet_size;
socket->seq += packet_size;
free(interrupt_message);
break;
}
else {
free(interrupt_message);
}
}
}
}
if (send_success) {
break;
}
}
if (!send_success) { //Got a timeout, should close down socket
*error = SOCKET_SENDERROR;
minisocket_destroy(socket);
return bytes_sent;
}
}
//printf("\n\n");
return bytes_sent;
}
minisocket_t* minisocket_client_create(const network_address_t addr, int port, minisocket_error *error) {
//Check socket number first
if (valid_server_port(port) == 0) {
*error = SOCKET_INVALIDPARAMS;
return NULL;
}
//Then check if we can make another client
if (client_count >= MAX_CLIENTS) {
*error = SOCKET_NOMOREPORTS;
return NULL;
}
//create new minisocket
minisocket_t* socket = (minisocket_t *) malloc(sizeof(minisocket_t));
if (socket == NULL) {
*error = SOCKET_OUTOFMEMORY;
return NULL; //OOM
}
while (mini_socket_data[next_port]) {
next_port = ((next_port + 1) % PORT_RANGE);
}
socket->socket_type = CLIENT_TYPE;
socket->local_port_number = next_port;
next_port = ((next_port + 1) % PORT_RANGE);
socket->state = CONNECTING;
socket->seq = 0;
socket->ack = 0;
network_address_copy(addr, socket->remote_address);
socket->remote_port_number = (unsigned short) port;
network_address_copy(addr, socket->remote_address);
socket->next_read = 0;
network_address_t my_address;
network_get_my_address(my_address);
network_address_copy(my_address, socket->local_address);
socket->datagrams_ready = semaphore_create();
semaphore_initialize(socket->datagrams_ready, 0);
socket->ack_ready = semaphore_create();
semaphore_initialize(socket->ack_ready, 0);
socket->incoming_data = queue_new();
socket->acknowledgements = queue_new();
//add socket to global array
mini_socket_data[socket->local_port_number] = socket;
mini_header_reliable_t header;
minisocket_create_reliable_header((mini_header_reliable_t *) &header, socket, socket->remote_port_number, addr, MSG_SYN);
//minisocket and header now created, try to establish connection
pack_unsigned_int(header.seq_number, socket->seq);
pack_unsigned_int(header.ack_number, socket->ack);
//send first message and wait for response
int response = 0; //no response yet
int timeout = START_TIMEOUT / 2; //this way first timeout will be at START_TIMEOUT
for (int i = 0; i < MAX_FAILURES; i++) {
printf("sending MSG_SYN in client, i: %d\n", i);
timeout = timeout * 2;
network_send_pkt(addr, sizeof(mini_header_reliable_t), (char *) &header, 0, empty_message);
alarm_id timeout_alarm_id = register_alarm(timeout, handshake_timeout_handler, (void *) socket->ack_ready);
int alarm_fired = 0;
while (!response && !alarm_fired) {
semaphore_P(socket->ack_ready);
//If queue length == 0, then the alarm must have fired
if (queue_length(socket->acknowledgements) == 0) {
alarm_fired = 1; //goes to next iteration of for loop
}
//otherwise, we received a packet
else {
network_interrupt_arg_t *interrupt_message;
interrupt_level_t old_level = set_interrupt_level(DISABLED);
queue_dequeue(socket->acknowledgements, (void **) &interrupt_message);
set_interrupt_level(old_level);
// if message not null
if (interrupt_message != NULL) {
mini_header_reliable_t* received_header = (mini_header_reliable_t *) interrupt_message->buffer;
network_address_t temp_address;
unpack_address(received_header->source_address, temp_address);
if (socket->remote_port_number == unpack_unsigned_short(received_header->source_port) &&
network_compare_network_addresses(socket->remote_address, temp_address) != 0) {
//if SYNACK
printf("CLIENT\n");
if (received_header->message_type == MSG_SYNACK) {
printf("GOT message SYN_ACK\n");
deregister_alarm(timeout_alarm_id);
response = 1;
break;
}
//if MSG_FIN
else if (received_header->message_type == MSG_FIN) {
printf("got message MSG_FIN in client\n");
//server already in use
deregister_alarm(timeout_alarm_id);
*error = SOCKET_BUSY;
response = 1;
minisocket_destroy(socket);
return NULL;
}
//WRONG MESSAGE TYPE
else {
printf("wrong message type received in client\n");
//TODO : try another message type, maybe do nothing?
}
}
}
}
}
if (response) {
break;
}
}
// timeout after 12.8s occured, close down socket
if (response != 1) {
printf("full timeout in client sending SYN\n");
*error = SOCKET_NOSERVER;
minisocket_destroy(socket);
return NULL;
}
// send final MSG_ACK once to server (future data packets will also have MSG_ACK as header type)
header.message_type = MSG_ACK;
printf("sending final MSG_ACK and leaving client create\n");
network_send_pkt(addr, sizeof(mini_header_reliable_t), (char *) &header, 0, empty_message);
socket->state = CONNECTED;
client_count++;
return socket;
}
minisocket_t* minisocket_server_create(int port, minisocket_error *error) {
//Check socket number first
if (valid_server_port(port) == 0) {
*error = SOCKET_INVALIDPARAMS;
return NULL;
}
//check if socket is already in use
if (mini_socket_data[port] != NULL) {
*error = SOCKET_PORTINUSE;
return NULL;
}
minisocket_t* socket = (minisocket_t *) malloc(sizeof(minisocket_t));
if (socket == NULL) {
*error = SOCKET_OUTOFMEMORY;
return NULL;
}
socket->state = LISTENING;
socket->socket_type = SERVER_TYPE;
socket->local_port_number = port;
network_address_t my_address;
network_get_my_address(my_address);
network_address_copy(my_address, socket->local_address);
socket->datagrams_ready = semaphore_create();
semaphore_initialize(socket->datagrams_ready, 0);
socket->ack_ready = semaphore_create();
semaphore_initialize(socket->ack_ready, 0);
socket->incoming_data = queue_new();
socket->acknowledgements = queue_new();
socket->seq = 0;
socket->ack = 0;
socket->next_read = 0;
//add socket to global array
mini_socket_data[socket->local_port_number] = socket;
char connection_established = 0;
mini_header_reliable_t header;
minisocket_create_reliable_header((mini_header_reliable_t *) &header, socket, socket->remote_port_number, socket->remote_address, MSG_SYNACK);
network_address_t dest;
pack_unsigned_int(header.seq_number, socket->seq);
pack_unsigned_int(header.ack_number, socket->ack);
//loop until a full connection is established
while (connection_established == 0) {
//sleep until initial MSG_SYN arrives from client
char message_received = 0;
while (message_received == 0) {
//Waits until it receives a packet
semaphore_P(socket->ack_ready);
interrupt_level_t old_level = set_interrupt_level(DISABLED);
network_interrupt_arg_t* interrupt_message = NULL;
queue_dequeue(socket->acknowledgements, (void **) &interrupt_message);
set_interrupt_level(old_level);
//TODO: check more contents of message? change seq and ack values in response??}
if (interrupt_message != NULL ) {
mini_header_reliable_t* received_header = (mini_header_reliable_t *) interrupt_message->buffer;
unpack_address(received_header->source_address, dest);
pack_address(header.destination_address, dest);
pack_unsigned_short(header.destination_port, unpack_unsigned_short(received_header->source_port));
if (valid_client_port(unpack_unsigned_short(received_header->source_port)) == 1) { //check valid port number
if (received_header->message_type != MSG_SYN) { //check valid message type
header.message_type = MSG_FIN;
network_send_pkt(dest, sizeof(mini_header_reliable_t), (char *) &header, 0, empty_message);
free(interrupt_message);
}
else {
//set remote port values
printf("server got the SYN message\n");
socket->remote_port_number = unpack_unsigned_short(received_header->source_port);
network_address_copy(dest, socket->remote_address);
socket->seq = unpack_unsigned_int(received_header->seq_number);
message_received = 1; //will break loop
free(interrupt_message);
socket->state = CONNECTING;
break;
}
}
}
}
//reset loop value for return
message_received = 0;
//otherwise the message was the correct type and format
int timeout = START_TIMEOUT / 2; //this way first timeout will be at START_TIMEOUT
for (int i = 0; i < MAX_FAILURES; i++) {
printf("sending MSG_SYNACK in server, i: %d\n", i);
timeout = timeout * 2;
header.message_type = MSG_SYNACK;
network_send_pkt(dest, sizeof(mini_header_reliable_t), (char *) &header, 0, empty_message);
alarm_id timeout_alarm_id = register_alarm(timeout, handshake_timeout_handler, (void *) socket->ack_ready);
int alarm_fired = 0;
//keep looking through received packets until either the alarm fires or it finds the correct packet
while (!connection_established && !alarm_fired) {
semaphore_P(socket->ack_ready);
//alarm has fired, since there are no packets to be received
if (queue_length(socket->acknowledgements) == 0) {
alarm_fired = 1; //goes to next iteration of for loop
}
//There is a packet (alarm hasnt fired yet)
else {
network_interrupt_arg_t* interrupt_message = NULL;
interrupt_level_t old_level = set_interrupt_level(DISABLED);
queue_dequeue(socket->acknowledgements, (void **) &interrupt_message);
set_interrupt_level(old_level);
// verify non null message
if (interrupt_message != NULL) {
mini_header_reliable_t* received_header = (mini_header_reliable_t *) interrupt_message->buffer;
network_address_t temp_address;
unpack_address(received_header->source_address, temp_address);
if (socket->remote_port_number == unpack_unsigned_short(received_header->source_port) &&
network_compare_network_addresses(socket->remote_address, temp_address) != 0 &&
received_header->message_type == MSG_ACK) {
//same address, same ports, right message
deregister_alarm(timeout_alarm_id); //only deregister alarm when the right packet is found
connection_established = 1;
//queue_prepend(socket->acknowledgements, interrupt_message); //ack works as well when there is data
break;
}
else {
free(interrupt_message);
}
}
}
}
if (connection_established) {
//correct response has been found, get out of this timeout loop!
break;
}
}
//if timeout occurs, will loop back to initial waiting phase for MSG_SYN from client
}
printf("leaving server create\n");
//update server socket values with client connection
socket->state = CONNECTED;
assert(socket != NULL);
return socket;
}
minisocket_t* minisocket_client_create(const network_address_t addr, int port, minisocket_error *error)
{
if (!addr || port < MIN_SERVER_PORT || port > MAX_SERVER_PORT) {
*error = SOCKET_INVALIDPARAMS;
return NULL;
}
int port_val = -1;
// CHECK what n_client_ports does
if (!ports[n_client_ports]) {
port_val = n_client_ports;
}
else {
for (int i = MIN_CLIENT_PORT; i <= MAX_CLIENT_PORT; i++) {
if (!ports[i]) {
port_val = i;
break;
}
}
}
n_client_ports = port_val + 1;
if (n_client_ports > MAX_CLIENT_PORT) {
n_client_ports = 0;
}
if (port_val == -1) {
*error = SOCKET_NOMOREPORTS;
return NULL;
}
minisocket_t *new_socket = (minisocket_t *) malloc(sizeof(minisocket_t));
if (!new_socket) {
*error = SOCKET_OUTOFMEMORY;
return NULL;
}
new_socket->socket_state = INITIAL;
semaphore_P(ports_mutex);
ports[port_val] = new_socket;
semaphore_V(ports_mutex);
new_socket->socket_type = 'c';
network_address_copy(local_host, new_socket->local_addr);
//network_get_my_address(new_socket->local_addr);
new_socket->local_port = port_val;
network_address_copy(addr, new_socket->remote_addr);
new_socket->remote_port = port;
new_socket->data = queue_new();
new_socket->data_ready = semaphore_create();
new_socket->wait_for_ack = semaphore_create();
new_socket->send_receive_mutex = semaphore_create();
semaphore_initialize(new_socket->data_ready, 0);
semaphore_initialize(new_socket->wait_for_ack, 0);
semaphore_initialize(new_socket->send_receive_mutex, 1);
new_socket->socket_state = WAITING_SYNACK;
minisocket_error s_error;
int wait_val = 100;
interrupt_level_t old_level;
while (wait_val <= 12800) {
send_control_message(MSG_SYN, new_socket->remote_port, new_socket->remote_addr, new_socket->local_port, 0, 0, &s_error);
new_socket->seq_number = 1;
new_socket->ack_number = 0;
if (s_error == SOCKET_OUTOFMEMORY) {
minisocket_free(new_socket);
semaphore_P(ports_mutex);
ports[new_socket->local_port] = NULL;
semaphore_V(ports_mutex);
*error = s_error;
return NULL;
}
alarm_id a = register_alarm(wait_val, (alarm_handler_t) semaphore_V, new_socket->data_ready);
semaphore_P(new_socket->data_ready);
old_level = set_interrupt_level(DISABLED);
if (queue_length(new_socket->data)) {
deregister_alarm(a);
}
set_interrupt_level(old_level);
if (!queue_length(new_socket->data)) {
wait_val *= 2;
continue;
}
network_interrupt_arg_t *arg = NULL;
queue_dequeue(new_socket->data, (void **) &arg);
mini_header_reliable_t *header = (mini_header_reliable_t *) arg->buffer;
network_address_t saddr;
unpack_address(header->source_address, saddr);
int sport = unpack_unsigned_short(header->source_port);
if (sport == new_socket->remote_port && network_compare_network_addresses(saddr, new_socket->remote_addr)) {
if (header->message_type - '0' == MSG_SYNACK) {
new_socket->seq_number = 1;
new_socket->ack_number = 1;
send_control_message(MSG_ACK, new_socket->remote_port, new_socket->remote_addr, new_socket->local_port, 1, 1, &s_error);
if (s_error == SOCKET_OUTOFMEMORY) {
minisocket_free(new_socket);
semaphore_P(ports_mutex);
ports[new_socket->local_port] = NULL;
semaphore_V(ports_mutex);
*error = s_error;
return NULL;
}
network_interrupt_arg_t *packet = NULL;
while (queue_dequeue(new_socket->data, (void **)&packet) != -1) {
free(packet);
}
semaphore_initialize(new_socket->data_ready, 0);
new_socket->socket_state = OPEN;
new_socket->seq_number = 2;
new_socket->ack_number = 1;
return new_socket;
}
if (header->message_type -'0' == MSG_FIN) {
minisocket_free(new_socket);
return NULL;
}
}
free(arg);
}
minisocket_free(new_socket);
return NULL;
}
int minisocket_send(minisocket_t *socket, const char *msg, int len, minisocket_error *error)
{
if (socket->socket_state == CLOSED || socket->socket_state == CLOSING) {
*error=SOCKET_SENDERROR;
return 0;
}
if (!socket || socket->socket_state != OPEN || !msg || len == 0)
{
*error = SOCKET_INVALIDPARAMS;
return -1;
}
semaphore_P(socket->send_receive_mutex);
int fragment_length = MAX_NETWORK_PKT_SIZE - sizeof(mini_header_reliable_t);
int transfer_length = len > fragment_length ? fragment_length : len;
//int start_byte = 0;
int sent_byte = 0;
do {
int wait = 100;
mini_header_reliable_t *header = create_control_header(MSG_ACK, socket->remote_port,
socket->remote_addr, socket->local_port,
socket->seq_number, socket->ack_number);
transfer_length = len - sent_byte > fragment_length ? fragment_length : len - sent_byte;
while (wait <= 12800) {
socket->ack_flag = 0;
int res = network_send_pkt(socket->remote_addr, sizeof(mini_header_reliable_t),
(char *)header, transfer_length, msg + sent_byte);
socket->seq_number += transfer_length;
if (res == -1) {
*error = SOCKET_SENDERROR;
semaphore_V(socket->send_receive_mutex);
return (sent_byte == 0) ? -1 : sent_byte;
}
alarm_id a = register_alarm(wait, (alarm_handler_t) semaphore_V, socket->data_ready);
semaphore_P(socket->wait_for_ack);
if (socket->socket_state == CLOSED || socket->socket_state == CLOSING) {
*error=SOCKET_SENDERROR;
return 0;
}
interrupt_level_t old_level = set_interrupt_level(DISABLED);
// Function was woken up by the firing of the alarm
if (socket->ack_flag == 0) {
wait *= 2;
socket->seq_number -= transfer_length;
semaphore_V(socket->send_receive_mutex);
set_interrupt_level(old_level);
continue;
}
// Function was woken up by the network handler
else if (socket->ack_flag == 1) {
// ACK has been received
deregister_alarm(a);
sent_byte += transfer_length;
semaphore_V(socket->send_receive_mutex);
set_interrupt_level(old_level);
break;
}
}
if (wait > 12800) {
*error = SOCKET_SENDERROR;
semaphore_V(socket->send_receive_mutex);
return (sent_byte == 0) ? -1 : sent_byte;
}
} while (sent_byte != len);
semaphore_V(socket->send_receive_mutex);
return len;
}
/* Transmit a packet and handle retransmissions */
int transmit_packet(minisocket_t socket, network_address_t dst_addr, int dst_port,
short incr_seq, char message_type, int data_len, char* data,
minisocket_error* error)
{
mini_header_reliable_t header;
int alarm_id;
short success = 0;
network_address_t my_addr;
int send_ret;
interrupt_level_t prev_level;
network_get_my_address(my_addr);
// Return if the socket is invalid
if (socket == NULL)
{
*error = SOCKET_INVALIDPARAMS;
return -1;
}
// Don't allow new packets to be transmitted if the port's closing
if (socket->status == TCP_PORT_CLOSING)
{
*error = SOCKET_SENDERROR;
return -1;
}
// Increment the seq# if needed
if (incr_seq == 1)
{
socket->seq_num++;
}
// Create the header
header = create_reliable_header(my_addr, socket->port_number, dst_addr,
dst_port, message_type, socket->seq_num,
socket->ack_num);
// Can retransmit for each timeout up to 6400 (100 + 200 + 400 + ... + 6400 = 12.7s)
socket->timeout = 100;
while (socket->timeout <= 6400)
{
// send the packet
send_ret = network_send_pkt(dst_addr, sizeof(struct mini_header_reliable),
(char*) header, data_len, (char*) data);
// Check if there was an error sending
if (send_ret == -1)
{
// Could've been a fluke, let it keep going
continue;
}
// Seq # is count of retransmissable packets... if dont increment it,
// then this isn't retransmissable, so end
if (incr_seq == 0)
{
free(header);
return 0;
}
// Set an alarm to wake us up after timeout
alarm_id = register_alarm(socket->timeout, &wake_up_sem, socket);
// Specify the type of packet we're waiting for
if (message_type == MSG_SYN)
{
socket->waiting = TCP_PORT_WAITING_SYNACK;
}
else
{
socket->waiting = TCP_PORT_WAITING_ACK;
}
// Sleep on semaphore
prev_level = set_interrupt_level(DISABLED);
semaphore_P(socket->wait_for_ack_sem);
set_interrupt_level(prev_level);
// Check if we got the packet when we've awoken
if (socket->waiting == TCP_PORT_WAITING_NONE)
{
// Yes, we did - delete the alarm and break out of the loop
deregister_alarm(alarm_id);
success = 1;
break;
}
else
{
if (socket->status == TCP_PORT_COULDNT_CONNECT)
{
// This means the client sent a FIN while we were trying to connect
success = 0;
deregister_alarm(alarm_id);
break;
}
// No, we didn't - double the timeout and repeat if we can
socket->timeout *= 2;
}
}
// So the IH knows the sequence is done (see comment block in network_common:170)
// There is a small chance that the code around network_common:170 won't catch
// this in time and won't send one last packet - that is okay, as Prof. Sirer
// mentioned sending that packet isn't even necessary in the first place.
socket->timeout = 100;
// Free the header as it's no longer needed
free(header);
// If we weren't successful...
if (success == 0)
{
// Decrement the seq# if we incremented it earlier
if (incr_seq == 1)
{
socket->seq_num--;
}
// Reset the socket's waiting status
socket->waiting = TCP_PORT_WAITING_NONE;
// Set the error & return
*error = SOCKET_NOSERVER;
return -1;
}
return 0;
}
minisocket_t* minisocket_server_create(int port, minisocket_error *error)
{
if (port < MIN_SERVER_PORT || port > MAX_SERVER_PORT) {
*error = SOCKET_INVALIDPARAMS;
return NULL;
}
if (ports[port]) {
*error = SOCKET_PORTINUSE;
return NULL;
}
minisocket_t *new_socket = (minisocket_t *) malloc(sizeof(minisocket_t));
if (!new_socket) {
*error = SOCKET_OUTOFMEMORY;
return NULL;
}
// Initialize new socket
new_socket->socket_state = INITIAL;
semaphore_P(ports_mutex);
ports[port] = new_socket;
semaphore_V(ports_mutex);
new_socket->socket_type = 's';
new_socket->local_port = port;
network_address_copy(local_host, new_socket->local_addr);
new_socket->data = queue_new();
new_socket->data_ready = semaphore_create();
new_socket->ack_flag = 0;
new_socket->wait_for_ack = semaphore_create();
new_socket->send_receive_mutex = semaphore_create();
semaphore_initialize(new_socket->data_ready, 0);
semaphore_initialize(new_socket->wait_for_ack, 0);
semaphore_initialize(new_socket->send_receive_mutex, 1);
interrupt_level_t old_level;
while (1) {
new_socket->seq_number = 0;
new_socket->ack_number = 0;
new_socket->remote_port = -1;
new_socket->remote_addr[0] = 0;
new_socket->remote_addr[1] = 0;
new_socket->socket_state = WAITING_SYN;
// receiving SYN
while (1) {
semaphore_P(new_socket->data_ready);
network_interrupt_arg_t *arg = NULL;
queue_dequeue(new_socket->data, (void **) &arg);
mini_header_reliable_t *header = (mini_header_reliable_t *) arg->buffer;
if (header->message_type -'0'== MSG_SYN) {
unpack_address(header->source_address, new_socket->remote_addr);
new_socket->remote_port = unpack_unsigned_short(header->source_port);
new_socket->socket_state = WAITING_ACK;
new_socket->seq_number = 0;
new_socket->ack_number = 1;
break;
}
else {
free(arg);
}
}
minisocket_error s_error;
int wait_val = 100;
while (wait_val <= 12800) {
send_control_message(MSG_SYNACK, new_socket->remote_port, new_socket->remote_addr, new_socket->local_port, 0 , 1, &s_error);
new_socket->seq_number = 1;
new_socket->ack_number = 1;
if (s_error == SOCKET_OUTOFMEMORY) {
minisocket_free(new_socket);
semaphore_P(ports_mutex);
ports[new_socket->local_port] = NULL;
semaphore_V(ports_mutex);
*error = s_error;
return NULL;
}
alarm_id a = register_alarm(wait_val, (alarm_handler_t) semaphore_V, new_socket->data_ready);
semaphore_P(new_socket->data_ready);
old_level = set_interrupt_level(DISABLED);
if (queue_length(new_socket->data)) {
deregister_alarm(a);
}
set_interrupt_level(old_level);
if (!queue_length(new_socket->data)) {
wait_val *= 2;
continue;
}
network_interrupt_arg_t *arg = NULL;
queue_dequeue(new_socket->data, (void **) &arg);
mini_header_reliable_t *header = (mini_header_reliable_t *) arg->buffer;
network_address_t saddr;
unpack_address(header->source_address, saddr);
int sport = unpack_unsigned_short(header->source_port);
if (header->message_type - '0' == MSG_SYN) {
if (new_socket->remote_port == sport && network_compare_network_addresses(new_socket->remote_addr, saddr)) {
continue;
}
send_control_message(MSG_FIN, sport, saddr, new_socket->local_port, 0, 0, &s_error);
}
if (header->message_type - '0' == MSG_ACK) {
if (new_socket->remote_port == sport && network_compare_network_addresses(new_socket->remote_addr, saddr)) {
network_interrupt_arg_t *packet = NULL;
while (queue_dequeue(new_socket->data, (void **)&packet) != -1) {
free(packet);
}
semaphore_initialize(new_socket->data_ready, 0);
new_socket->socket_state = OPEN;
new_socket->seq_number = 1;
new_socket->ack_number = 2;
return new_socket;
}
}
free (arg);
}
}
return NULL;
}
void minisocket_handle_tcp_packet(network_interrupt_arg_t *arg)
{
mini_header_reliable_t *header = (mini_header_reliable_t *) (arg->buffer);
int port = unpack_unsigned_short(header->destination_port);
if (port < MIN_SERVER_PORT || port > MAX_CLIENT_PORT || !ports[port]) {
free(arg);
return;
}
if (ports[port]->socket_state == INITIAL || ports[port]->socket_state == CLOSED) {
free(arg);
return;
}
if (ports[port]->socket_state != OPEN) {
// handled in handshake
queue_append(ports[port]->data, arg);
semaphore_V(ports[port]->data_ready);
return;
}
minisocket_error s_error;
network_address_t saddr;
unpack_address(header->source_address, saddr);
int sport = unpack_unsigned_short(header->source_port);
if (!network_compare_network_addresses(ports[port]->remote_addr, saddr) || ports[port]->remote_port != sport) {
if(header->message_type -'0' == MSG_SYN)
{
send_control_message(MSG_FIN, sport, saddr, port, 0, 0, &s_error);
}
free(arg);
return;
}
//If the message is of type SYNACK and from the same client
if (header->message_type - '0' == MSG_SYNACK) {
send_control_message(MSG_ACK, sport, saddr, port, 0, 0, &s_error);
free(arg);
return;
}
//If the message is of type FIN
if (header->message_type - '0' == MSG_FIN) {
ports[port]->ack_number += 1;
send_control_message(MSG_ACK, sport, saddr, port, ports[port]->seq_number, ports[port]->ack_number, &s_error);
ports[port]->socket_state = CLOSING;
int count = semaphore_get_count(ports[port]->data_ready);
while (count < 0) {
semaphore_V(ports[port]->data_ready);
count++;
}
register_alarm(15000, (alarm_handler_t) minisocket_close, ports[port]);
//minisocket_free(ports[port]);
free(arg);
return;
}
//If the message is of type ACK from the same client
if (header->message_type - '0' == MSG_ACK)
{
unsigned int ack_no = unpack_unsigned_int(header->ack_number);
int packet_size = arg->size - sizeof(mini_header_reliable_t);
minisocket_error s_error;
//If it's a correct acknowledgement of the sent data, enqueue it and V the wait for ack semaphore
if (ack_no == ports[port]->seq_number/* + MAX_NETWORK_PKT_SIZE - sizeof(mini_header_reliable_t) + 1*/) {
if (packet_size != 0) {
queue_append(ports[port]->data, arg);
semaphore_V(ports[port]->data_ready);
ports[port]->ack_number += packet_size;
send_control_message(MSG_ACK, sport, saddr, port, ports[port]->seq_number, ports[port]->ack_number, &s_error);
}
if (ports[port]->ack_flag == 0) {
ports[port]->ack_flag = 1;
semaphore_V(ports[port]->wait_for_ack);
}
return;
}
else {
free(arg);
return;
}
}
}
void network_handler(network_interrupt_arg_t* packet) {
interrupt_level_t old_level = set_interrupt_level(DISABLED);
//strip relevant packet header information
mini_header_t* header = (mini_header_t *) packet->buffer;
unsigned short dest_port = unpack_unsigned_short(header->destination_port);
char packet_protocol = header->protocol;
if (packet_protocol == PROTOCOL_MINIDATAGRAM) {
//appends entire packet (including header) to the relevant miniport queue
miniport_t* mini = minimsg_get_port(dest_port);
if (mini == NULL) {
set_interrupt_level(old_level);
free(packet);
return; //unallocated mini_port within minimsg, so drop packet!
}
//wake up possible waiting threads (or keep track of enqueued packets)
queue_append(mini->port_data.incoming_data, packet);
semaphore_V(mini->port_data.datagrams_ready);
set_interrupt_level(old_level);
}
else {
//printf("handling TCP packet\n\n");
mini_header_reliable_t* received_header = (mini_header_reliable_t *) packet->buffer;
minisocket_t* socket = minisocket_get_socket(dest_port);
if (socket == NULL) {
printf("no socket found type: %u\n", received_header->message_type);
free(packet);
set_interrupt_level(old_level);
return;
}
//check packet size
if (packet->size < sizeof(mini_header_reliable_t)) {
free(packet);
return;
}
//sending header data
network_address_t send_address;
unpack_address(received_header->source_address, send_address);
mini_header_reliable_t send_header;
unsigned short source_port = unpack_unsigned_short(received_header->source_port);
minisocket_create_reliable_header((mini_header_reliable_t *) &send_header, socket, source_port, send_address, MSG_ACK);
if (socket->state == CLOSED && received_header->message_type == MSG_FIN) {
printf("ACKing FIN packet\n");
//closed socket that hasn't been re-allocated, send back MSG_ACK
send_header.message_type = MSG_ACK;
network_send_pkt(send_address, sizeof(mini_header_reliable_t), (char *) &send_header, 0, NULL);
free(packet);
set_interrupt_level(old_level);
return;
}
if (socket->state == CONNECTING || socket->state == LISTENING) {
//currently trying to establish a connection to socket
queue_append(socket->acknowledgements, packet);
semaphore_V(socket->ack_ready);
set_interrupt_level(old_level);
return;
}
//check that this packet source information matches expected socket connection
if (socket->state == CONNECTED && socket->remote_port_number == source_port && network_compare_network_addresses(socket->remote_address, send_address) != 0) {
if (packet->size == sizeof(mini_header_reliable_t) && received_header->message_type == MSG_ACK) {
//printf("got empty ACK packet with ack: %u\n", unpack_unsigned_int(received_header->ack_number));
// received ack return message for pending sent message
queue_append(socket->acknowledgements, packet);
semaphore_V(socket->ack_ready);
set_interrupt_level(old_level);
return;
}
if (packet->size == sizeof(mini_header_reliable_t) && received_header->message_type == MSG_SYNACK) {
send_header.message_type = MSG_ACK;
network_send_pkt(send_address, sizeof(mini_header_reliable_t), (char *) &send_header, 0, NULL);
free(packet);
return;
}
if (received_header->message_type == MSG_FIN) {
printf("received messsage FIN\n");
// received termination message for currently connected socket
// send back MSG_ACK to closer
send_header.message_type = MSG_ACK;
network_send_pkt(send_address, sizeof(mini_header_reliable_t), (char *) &send_header, 0, NULL);
//mark socket as closed, so no further calls can be made to send() or receive()
socket->state = CLOSED;
printf("REGISTERING ALARM\n");
//sleep for 15s before destroying the socket
register_alarm(15000, minisocket_destroy, (void *) socket);
set_interrupt_level(old_level);
return;
}
//check sequence number
unsigned int seq_number = unpack_unsigned_int(received_header->seq_number);
if (seq_number < socket->ack) {
//printf("already seen this!\n");
//have seen this packet before, send an ACK to client
send_header.message_type = MSG_ACK;
network_send_pkt(send_address, sizeof(mini_header_reliable_t), (char *) &send_header, 0, NULL);
//free(packet);
set_interrupt_level(old_level);
return;
}
else if (seq_number > socket->ack) {
//printf("don't want packet yet!\n");
//want to wait for earlier sequential packet
free(packet);
set_interrupt_level(old_level);
return;
}
else if (seq_number == socket->ack && received_header->message_type == MSG_ACK && packet->size > sizeof(mini_header_reliable_t)) { //else seq_number == socket->ack
// append data packet and increment ack number
queue_append(socket->incoming_data, packet);
semaphore_V(socket->datagrams_ready);
send_header.message_type = MSG_ACK;
unsigned int new_ack = seq_number + packet->size - sizeof(mini_header_reliable_t);
pack_unsigned_int(send_header.ack_number, new_ack);
socket->ack = new_ack;
//printf("sending ack %u\n", socket->ack);
network_send_pkt(send_address, sizeof(mini_header_reliable_t), (char *) &send_header, 0, NULL);
set_interrupt_level(old_level);
}
}
else {
//send back a MSG_FIN to request that this client stop sending messages
network_send_pkt(send_address, sizeof(mini_header_reliable_t), (char *) &send_header, 0, NULL);
set_interrupt_level(old_level);
}
}
}
/* sends a miniroute packet, automatically discovering the path if necessary. See description in the
* .h file.
*/
int miniroute_send_pkt(network_address_t dest_address, int hdr_len, char* hdr, int data_len, char* data)
{
// This will store the route request struct, which is a structure related to the
// search for a path to the host
route_request_t route_request;
// Store the routing header
routing_header_t routing_header;
// Store the route to the host, which is an array of addresses
network_address_t* route;
// Store the route data struct, which holds the route and some metadata
route_data_t route_data;
// Store my address
network_address_t my_addr;
// Used to synchronize access with structures the network handler touches
interrupt_level_t prev_level;
// This will store the combined routing + normal headers
char* full_header;
network_address_t dest_address2;
// These will store data related to the routes
int time_route_found;
int route_len;
int route_valid = 1;
// Used to get data from the header containing the paht
routing_header_t tmp_routing_header;
// Used to just check the IP of senders; combats UDP port issues w/ simulated broadcasts
unsigned int dest_address_ip = dest_address[0];
// Loop + tmp variables
int current_req_id;
int success = 0;
int alarm_id;
int x;
int i;
if (hdr_len == 0 || hdr == NULL
|| data_len == 0 || data == NULL)
return -1;
// Get the route item, which is a hashmap_item_t, from the hashmap for this addr
semaphore_P(route_cache_sem);
route_data = (route_data_t) hashmap_get(route_cache, hash_address(dest_address));
// If it's not NULL, extract the data from the item
if (route_data != NULL)
{
time_route_found = route_data->time_found;
route_len = route_data->route_len;
// caveat: the cleanup thread may delete the route data, so we need to
// save it in a separate variable, just incase.
route = (network_address_t*) malloc(sizeof(network_address_t) * route_len);
if (route == NULL)
{
semaphore_V(route_cache_sem);
return -1;
}
memcpy(route, route_data->route, sizeof(network_address_t) * route_len);
}
else
{
route_valid = 0;
}
semaphore_V(route_cache_sem);
// Check, if the route isn't NULL, if it's expired
if (route_valid == 1 && (ticks - time_route_found) * PERIOD/MILLISECOND > 3000)
{
route_valid = 0;
}
// If the route is invalid (either not in the cache or expired)...
if (route_valid == 0)
{
// We won't be needing that previous route variable
if (route_data != NULL)
{
// But, just in case someone is still using it, use the route cache semaphore
semaphore_P(route_cache_sem);
free(route);
semaphore_V(route_cache_sem);
}
// Check if someone else already initiated this route discovery request
prev_level = set_interrupt_level(DISABLED);
route_request = (route_request_t) hashmap_get(current_discovery_requests, dest_address_ip);
set_interrupt_level(prev_level);
// If so, we can just wait for their result
if (route_request != NULL)
{
// Wait for the other thread to get the path
// The threads waiting variable needs to be synchronized. We decided
// to reuse the route cache sem, as there will not be much lock
// contention
semaphore_P(route_cache_sem);
route_request->threads_waiting++;
semaphore_V(route_cache_sem);
semaphore_P(route_request->waiting_sem);
// Get the route from the hashmap
semaphore_P(route_cache_sem);
route_data = (route_data_t) hashmap_get(route_cache, hash_address(dest_address));
// If the other thread didn't get the route, return an error
if (route_data == NULL)
{
// Return failure...
semaphore_V(route_cache_sem);
return -1;
}
else
{
time_route_found = route_data->time_found;
route_len = route_data->route_len;
if ((ticks - time_route_found) * PERIOD/MILLISECOND > 3000)
{
// This could have been a left-over expired cache entry that we haven't
// deleted yet.
semaphore_V(route_cache_sem);
return -1;
}
// Save the route in a separate variable in case the route gets cleaned up
// while we're using it
route = (network_address_t*) malloc(sizeof(network_address_t) * route_len);
if (route == NULL)
{
semaphore_V(route_cache_sem);
return -1;
}
memcpy(route, route_data->route, sizeof(network_address_t) * route_len);
semaphore_V(route_cache_sem);
}
}
else
{
// Otherwise, we have to do the route discovery process
// Create a new route request struct
route_request = create_route_request();
if (route_request == NULL)
{
return -1;
}
// Add the route request to the current discovery requests
prev_level = set_interrupt_level(DISABLED);
hashmap_insert(current_discovery_requests, dest_address_ip, route_request);
set_interrupt_level(prev_level);
// We'll try the route discovery process three times
for (i = 0; i < 3; i++)
{
// Register an alarm to wake this thread up as it waits for a response
alarm_id = register_alarm(12000, &alarm_wakeup_sem, (void*) route_request->initiator_sem);
// Increment the request ID - must be synchronized, obviously
semaphore_P(request_id_sem);
current_req_id = route_request_id++;
semaphore_V(request_id_sem);
// We need to make a header for the discovery request, but the path
// needs to have our address in it, so the reply can be forwarded back
// to us
network_get_my_address(my_addr);
// Passing in the address of this local variable will suffice, as the
// value is immediately copied into the header and then not used again
// Create a routing header for the route discovery request
routing_header = create_miniroute_header(ROUTING_ROUTE_DISCOVERY,
dest_address, current_req_id,
MAX_ROUTE_LENGTH, 1,
&my_addr);
if (routing_header == NULL)
{
return -1;
}
// Combine it with the given header
full_header = merge_headers(routing_header, hdr, hdr_len);
if (full_header == NULL)
{
free(routing_header);
return -1;
}
// Send out the route discovery request
network_bcast_pkt(sizeof(struct routing_header)+hdr_len,
(char*) full_header, data_len, data);
// Wait for a reply (which will be signalled by the network handler)
prev_level = set_interrupt_level(DISABLED);
semaphore_P(route_request->initiator_sem);
set_interrupt_level(prev_level);
// Check if we got a successful response
if (route_request->interrupt_arg != NULL)
{
// Deregister the alarm before it tries to wake us up
// Needs to be synchronized, as the IH touches it and we destroy it here
prev_level = set_interrupt_level(alarm_id);
deregister_alarm(alarm_id);
set_interrupt_level(alarm_id);
// Get the header
tmp_routing_header = (routing_header_t) route_request->interrupt_arg->buffer;
route_len = unpack_unsigned_int(tmp_routing_header->path_len);
// Then the path, for our own use later in this function
// We'll also create one copy and put it in the route data struct
route = miniroute_reverse_raw_path(tmp_routing_header, route_len);
if (route == NULL)
{
free(routing_header);
free(full_header);
return -1;
}
// Create a route data struct - with a different route (as it will be deleted by a diff thread)
route_data = create_route_data(miniroute_reverse_raw_path(tmp_routing_header, route_len),
route_len, ticks);
if (route_data == NULL)
{
free(routing_header);
free(full_header);
return -1;
}
// add it to the cache hashmap
semaphore_P(route_cache_sem);
hashmap_insert(route_cache, hash_address(dest_address), route_data);
semaphore_V(route_cache_sem);
// Wake up the other threads waiting
for (x = 0; x < route_request->threads_waiting; x++)
{
semaphore_V(route_request->waiting_sem);
}
// Clean up the route request struct, then delete it from the hashmap
// DELETE ROUTE REQUEST WILL FREE THE NETWORK INTERRUPT ARG!
prev_level = set_interrupt_level(DISABLED);
delete_route_request(route_request);
hashmap_delete(current_discovery_requests, dest_address_ip);
set_interrupt_level(prev_level);
// We don't need to actually get any of the routing stuff from the
// route_ite, as this process also sent the data packet
// Free the headers
free(routing_header);
free(full_header);
// Return the total bytes sent, not including the routing header
success = 1;
break;
}
}
// If we didn't get a successful response after 3 tries...
if (success == 0)
{
// Wake up the other threads waiting so they can see we failed
for (x = 0; x < route_request->threads_waiting; x++)
{
semaphore_V(route_request->waiting_sem);
}
// clean up the route request struct, then delete it from the hashmap
prev_level = set_interrupt_level(DISABLED);
delete_route_request(route_request);
hashmap_delete(current_discovery_requests, dest_address_ip);
set_interrupt_level(prev_level);
// Free the headers
free(routing_header);
free(full_header);
// Return failure...
return -1;
}
}
}
// If we're here, we either found the route in the cache or waited for another
// thread to finish getting the route (and it did so successfully)
network_address_copy(route[route_len-1], dest_address2);
// Need to update the dst address to deal with UDP port issues
// This again is due to UDP port issues...
pack_address(((mini_header_t) hdr)->destination_address, dest_address2);
// Create a routing header for the data packet
routing_header = create_miniroute_header(ROUTING_DATA,
dest_address2, 0,
MAX_ROUTE_LENGTH, route_len,
route);
if (routing_header == NULL)
{
return -1;
}
// Combine it with the given header
full_header = merge_headers(routing_header, hdr, hdr_len);
if (full_header == NULL)
{
free(routing_header);
}
// Set the right destination address
network_address_copy(route[1], dest_address2);
// Send the packet
network_send_pkt(dest_address2, sizeof(struct routing_header) + hdr_len,
full_header, data_len, data);
// Free the route + headers
free(route);
free(routing_header);
free(full_header);
// Return the total data sent
return hdr_len + data_len;
}
