dataReceiver.c

#include <netdb.h>
#include <stdio.h>
#include <arpa/inet.h>
#include "../../defines.h"
#include "../../util/dbg.h"
#include "../../util/common.h"
#include "../block.h"
#include "../clock.h"
#include "../socket.h"
#include "dataReceiver.h"

void retrieve_data_blocks(PrrtSocket *sock_ptr, prrtSequenceNumber_t base_seqno, uint8_t k, const PrrtBlock *block)
{
    List *res = List_create();
    BPTree_get_range(sock_ptr->dataStore, res, base_seqno, base_seqno + k - 1);

    LIST_FOREACH(res, first, next, cur) {
        PrrtPacket *packetPtr = cur->value;
        check(PrrtBlock_insert_data_packet((PrrtBlock *) block, packetPtr), "Insert failed!")
        sock_ptr->dataStore = BPTree_delete(sock_ptr->dataStore, packetPtr->sequenceNumber);
    }
    error:
    List_destroy(res);
}

void decode_block(PrrtSocket *sock_ptr, PrrtBlock *block, prrtSequenceNumber_t base_seqno)
{
    if(block != NULL && PrrtBlock_decode_ready(block)) {
        check(PrrtBlock_decode(block), "Decoding failed");

        while(List_count(block->dataPackets) > 0) {
            PrrtPacket *pkt = List_shift(block->dataPackets);
            if(PrrtForwardPacketTable_test_set_is_number_relevant(sock_ptr->forwardPacketTable, pkt->sequenceNumber)) {
                check(pthread_mutex_lock(&sock_ptr->inQueueFilledMutex) == 0, "Lock failed.");
                List_push(sock_ptr->inQueue, pkt);
                check(pthread_cond_signal(&sock_ptr->inQueueFilledCv) == 0, "Signal failed.");
                check(pthread_mutex_unlock(&sock_ptr->inQueueFilledMutex) == 0, "Unlock failed.");
            } else {
                PrrtPacket_destroy(pkt);
            }
        }

        PrrtBlock_destroy(block);

        sock_ptr->blockStore = BPTree_delete(sock_ptr->blockStore, base_seqno);
    }

    return;
    error:
    PERROR("Decoding failed.%s", "")
}

bool send_feedback(const PrrtSocket *sock_ptr, struct sockaddr_in remote)
{
    uint16_t remote_port = ntohs(remote.sin_port);
    char *remote_host = inet_ntoa(remote.sin_addr);

    struct sockaddr_in targetaddr;
    memset((char *) &targetaddr, 0, sizeof(targetaddr));
    targetaddr.sin_family = AF_INET;
    targetaddr.sin_port = htons((uint16_t) (remote_port + 1));

    struct hostent *hp;
    hp = gethostbyname(remote_host);
    memcpy((void *) &targetaddr.sin_addr, hp->h_addr_list[0], (size_t) hp->h_length);

    PrrtPacket *feedback_pkt_ptr = PrrtPacket_create_feedback_packet(0, 19, 4715, 3, 4, 6, 8, 9, 5,
                                                                     sock_ptr->address->sin_addr.s_addr);
    prrtPacketLength_t length = PrrtPacket_size(feedback_pkt_ptr);
    void *buf = calloc(1, length);
    check_mem(buf);

    check(PrrtPacket_encode(buf, MAX_PAYLOAD_LENGTH, feedback_pkt_ptr), "Buffer for encoding feedback is too small");

    prrtTimestamp_t forwardTripTime = htonl(PrrtClock_get_current_time() + sock_ptr->lastSentTimestamp - sock_ptr->lastReceivedTimestamp);
    ((PrrtPacketFeedbackPayload*) (buf + PRRT_PACKET_ENCODED_GENERAL_HEADER_LENGTH))->forwardTripTimestamp_us = forwardTripTime;
    // TODO: [LATENCY] By knowing the time for htonl and writing bytes, one could compensate the timestamp.
    check(sendto(sock_ptr->feedbackSocketFd, buf, length, 0, (struct sockaddr *) &targetaddr, sizeof(targetaddr)) ==
          length, "Sending feedback failed.");
    free(buf);

    PrrtPacket_destroy(feedback_pkt_ptr);

    return true;

    error:
    if(buf != NULL) { free(buf); }
    if(feedback_pkt_ptr != NULL) { PrrtPacket_destroy(feedback_pkt_ptr); }
    return false;
}

void *receive_data_loop(void *ptr)
{
    ssize_t n;
    struct sockaddr_in remote;
    socklen_t addrlen = sizeof(remote);
    unsigned char buffer[MAX_PAYLOAD_LENGTH];
    PrrtSocket *sock_ptr = ptr;

    while(1) {
        memset(buffer, 0, MAX_PAYLOAD_LENGTH);
        n = recvfrom(sock_ptr->dataSocketFd, buffer, MAX_PAYLOAD_LENGTH, 0, (struct sockaddr *) &remote, &addrlen);
        sock_ptr->lastReceivedTimestamp = PrrtClock_get_current_time();

        PrrtPacket *packet = (PrrtPacket *) calloc(1, sizeof(PrrtPacket));
        check_mem(packet);
        check(PrrtPacket_decode(buffer, (uint16_t) n, packet), "Decode failed.");

        // TODO: make something useful with RTT approximation
        PrrtPacketDataPayload* payload = packet->payload;
        debug("RTT: %d", payload->groupRTT_us);

        sock_ptr->lastSentTimestamp = PrrtPacket_get_data_timestamp(packet);

        check(send_feedback(sock_ptr, remote), "Sending feedback failed.");

        prrtPacketType_t packetType = PrrtPacket_type(packet);
        if(packetType == PACKET_TYPE_DATA) {
            // TODO: packet.timestamp + packet.timeout < now: break

            if(PrrtForwardPacketTable_test_set_is_number_relevant(sock_ptr->forwardPacketTable, packet->sequenceNumber) ==
               false) {
                PrrtPacket_destroy(packet);
            } else {
                prrtSequenceNumber_t baseSequenceNumber = packet->sequenceNumber - packet->index;

                PrrtPacket *reference = PrrtPacket_copy(packet);

                PrrtBlock *block = BPTree_get(sock_ptr->blockStore, baseSequenceNumber);
                if(block != NULL) {
                    check(PrrtBlock_insert_data_packet(block, reference), "Inserting failed");
                    decode_block(sock_ptr, block, baseSequenceNumber);
                } else {
                    // Check for duplicate data packet.
                    if(BPTree_get(sock_ptr->dataStore, packet->sequenceNumber) == NULL) {
                        sock_ptr->dataStore = BPTree_insert(sock_ptr->dataStore, packet->sequenceNumber, reference);
                    } else {
                        PrrtPacket_destroy(reference);
                    }
                }

                // forward to application layer

                check(pthread_mutex_lock(&sock_ptr->inQueueFilledMutex) == 0, "Lock failed.");
                List_push(sock_ptr->inQueue, packet);
                check(pthread_cond_signal(&sock_ptr->inQueueFilledCv) == 0, "Cond signal failed.");
                check(pthread_mutex_unlock(&sock_ptr->inQueueFilledMutex) == 0, "Unlock failed.");
            }
        } else if(packetType == PACKET_TYPE_REDUNDANCY) {
            PrrtPacketRedundancyPayload *redundancyPayload = packet->payload;

            if(!PrrtForwardPacketTable_test_is_block_relevant(sock_ptr->forwardPacketTable,
                                                              redundancyPayload->baseSequenceNumber,
                                                              redundancyPayload->n)) {
                PrrtPacket_destroy(packet);
            } else {
                PrrtBlock *block = BPTree_get(sock_ptr->blockStore, redundancyPayload->baseSequenceNumber);
                if(block == NULL) {
                    // TODO: PROPER CREATION
                    PrrtCodingParams *cpar = PrrtCodingParams_create();
                    cpar->k = redundancyPayload->k;
                    cpar->n = redundancyPayload->n;

                    block = PrrtBlock_create(cpar, redundancyPayload->baseSequenceNumber);
                    PrrtCodingParams_destroy(cpar);

                    sock_ptr->blockStore = BPTree_insert(sock_ptr->blockStore, redundancyPayload->baseSequenceNumber,
                                                         block);
                }

                retrieve_data_blocks(sock_ptr, redundancyPayload->baseSequenceNumber, block->codingParams.k, block);

                if(PrrtBlock_insert_redundancy_packet(block, packet)) {
                    decode_block(sock_ptr, block, redundancyPayload->baseSequenceNumber);
                } else {
                    PrrtPacket_destroy(packet);
                }
            }
        } else {
            PrrtPacket_print(packet);
            PrrtPacket_destroy(packet);
        }
    }

    // TODO: occasionally clean up dataStore and blockStore !!!

    error:
    PNOTIMPLEMENTED("SHOULD IMPLEMENT ERROR HANDLER HERE");
}