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receiver.c
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receiver.c
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#include "receiver.h"
void init_receiver(Receiver * receiver,
int id)
{
receiver->recv_id = id;
receiver->input_framelist_head = NULL;
receiver->NFE = 0;
int i;
for(i = 0; i < 8; i++)
{
//receiver->recvQ[i].msg = malloc(sizeof(Frame));
receiver->recvQ[i].received = false;
}
}
void handle_incoming_msgs(Receiver * receiver,
LLnode ** outgoing_frames_head_ptr)
{
//TODO: Suggested steps for handling incoming frames
// 1) Dequeue the Frame from the sender->input_framelist_head
// 2) Convert the char * buffer to a Frame data type
// 3) Check whether the frame is corrupted
// 4) Check whether the frame is for this receiver
// 5) Do sliding window protocol for sender/receiver pair
int incoming_msgs_length = ll_get_length(receiver->input_framelist_head);
while (incoming_msgs_length > 0)
{
//printf("incoming_msgs: %d\n", incoming_msgs_length);
//Pop a node off the front of the link list and update the count
LLnode * ll_inmsg_node = ll_pop_node(&receiver->input_framelist_head);
incoming_msgs_length = ll_get_length(receiver->input_framelist_head);
//DUMMY CODE: Print the raw_char_buf
//NOTE: You should not blindly print messages!
// Ask yourself: Is this message really for me?
// Is this message corrupted?
// Is this an old, retransmitted message?
char * raw_char_buf = (char *) ll_inmsg_node->value;
Frame * inframe = convert_char_to_frame(raw_char_buf);
//check whether frame is corrupted
int corrupted = is_corrupted(raw_char_buf, 64);
//printf("corrupted: %d\n", corrupted);
if(corrupted == 0 && inframe->recvId == receiver->recv_id)
{
struct recvQ_slot *slot;
slot = &receiver->recvQ[inframe->seqNum%8];
if(!swpInWindow(inframe->seqNum, receiver->NFE, receiver->NFE+8-1))
return;
//slot->msg = inframe;
slot->msg = malloc(sizeof(Frame));
slot->msg->sendId = inframe->sendId;
slot->msg->recvId = inframe->recvId;
slot->msg->seqNum = inframe->seqNum;
slot->msg->ackNum = inframe->ackNum;
slot->msg->flag = inframe->flag;
memcpy(slot->msg->data, inframe->data, FRAME_PAYLOAD_SIZE);
slot->msg->crc = inframe->crc;
fprintf(stderr, "slot index: %d\n", inframe->seqNum%8);
fprintf(stderr, "slot content: %s\n", inframe->data);
slot->received = true;
fprintf(stderr, "seqNum is: %d, NFE is: %d\n", inframe->seqNum, receiver->NFE);
if(inframe->seqNum == receiver->NFE)
{
while(slot->received)
{
printf("<RECV_%d>:[%s]\n", receiver->recv_id, slot->msg->data);
slot->received = false;
++receiver->NFE;
fprintf(stderr, "new NFE: %d\n", receiver->NFE);
slot = &receiver->recvQ[receiver->NFE%8];
}
}
inframe->flag = 1;
if(receiver->NFE == 0)
inframe->ackNum = 0;
else
inframe->ackNum = receiver->NFE-1;
fprintf(stderr, "ackNum is : %d\n", inframe->ackNum);
char* char_buf = convert_frame_to_char(inframe);
append_crc(char_buf, 64);
ll_append_node(outgoing_frames_head_ptr, char_buf);
}
//Free raw_char_buf
free(raw_char_buf);
free(inframe);
free(ll_inmsg_node);
}
}
void * run_receiver(void * input_receiver)
{
struct timespec time_spec;
struct timeval curr_timeval;
const int WAIT_SEC_TIME = 0;
const long WAIT_USEC_TIME = 100000;
Receiver * receiver = (Receiver *) input_receiver;
LLnode * outgoing_frames_head;
//This incomplete receiver thread, at a high level, loops as follows:
//1. Determine the next time the thread should wake up if there is nothing in the incoming queue(s)
//2. Grab the mutex protecting the input_msg queue
//3. Dequeues messages from the input_msg queue and prints them
//4. Releases the lock
//5. Sends out any outgoing messages
pthread_cond_init(&receiver->buffer_cv, NULL);
pthread_mutex_init(&receiver->buffer_mutex, NULL);
while(1)
{
//NOTE: Add outgoing messages to the outgoing_frames_head pointer
outgoing_frames_head = NULL;
gettimeofday(&curr_timeval,
NULL);
//Either timeout or get woken up because you've received a datagram
//NOTE: You don't really need to do anything here, but it might be useful for debugging purposes to have the receivers periodically wakeup and print info
time_spec.tv_sec = curr_timeval.tv_sec;
time_spec.tv_nsec = curr_timeval.tv_usec * 1000;
time_spec.tv_sec += WAIT_SEC_TIME;
time_spec.tv_nsec += WAIT_USEC_TIME * 1000;
if (time_spec.tv_nsec >= 1000000000)
{
time_spec.tv_sec++;
time_spec.tv_nsec -= 1000000000;
}
//*****************************************************************************************
//NOTE: Anything that involves dequeing from the input frames should go
// between the mutex lock and unlock, because other threads CAN/WILL access these structures
//*****************************************************************************************
pthread_mutex_lock(&receiver->buffer_mutex);
//Check whether anything arrived
int incoming_msgs_length = ll_get_length(receiver->input_framelist_head);
if (incoming_msgs_length == 0)
{
//Nothing has arrived, do a timed wait on the condition variable (which releases the mutex). Again, you don't really need to do the timed wait.
//A signal on the condition variable will wake up the thread and reacquire the lock
pthread_cond_timedwait(&receiver->buffer_cv,
&receiver->buffer_mutex,
&time_spec);
}
handle_incoming_msgs(receiver,
&outgoing_frames_head);
pthread_mutex_unlock(&receiver->buffer_mutex);
//CHANGE THIS AT YOUR OWN RISK!
//Send out all the frames user has appended to the outgoing_frames list
int ll_outgoing_frame_length = ll_get_length(outgoing_frames_head);
while(ll_outgoing_frame_length > 0)
{
LLnode * ll_outframe_node = ll_pop_node(&outgoing_frames_head);
char * char_buf = (char *) ll_outframe_node->value;
//The following function frees the memory for the char_buf object
send_msg_to_senders(char_buf);
//Free up the ll_outframe_node
free(ll_outframe_node);
ll_outgoing_frame_length = ll_get_length(outgoing_frames_head);
}
}
pthread_exit(NULL);
}