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"

static void
retrieve_data_blocks(PrrtSocket *sock_ptr, prrtSequenceNumber_t base_seqno, uint8_t k, const PrrtBlock *block) {
    List *res = List_create();

    PrrtDataPacketStore_remove_range(sock_ptr->dataPacketStore, res, base_seqno,
                                     (prrtSequenceNumber_t) (base_seqno + k - 1));

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

static void decode_block(PrrtSocket *sock_ptr, PrrtBlock *block) {
    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)) {
                Pipe_push(sock_ptr->inQueue, &pkt->asListNode);
            } else {
                PrrtPacket_destroy(pkt);
            }
        }

        PrrtRepairBlockStore_delete(sock_ptr->repairBlockStore, block->baseSequenceNumber);
        PrrtBlock_destroy(block);
    }

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

static 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);

    prrtTimestamp_t forwardTripTime = (uint32_t) (((int64_t) PrrtClock_get_current_time_us()) +
                                                  (sock_ptr->lastSentTimestamp - sock_ptr->lastReceivedTimestamp));

    PrrtPacket *feedback_pkt_ptr = PrrtPacket_create_feedback_packet(0, 19, 4715, 0, 4, 6, 8, 9, 5,
                                                                     sock_ptr->address->sin_addr.s_addr,
                                                                     forwardTripTime);
    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");

    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;
}

static bool is_timeout(prrtTimestamp_t now, prrtTimestamp_t to) {
    /* TODO: implement */
    return false;
}

static void handle_data_packet(PrrtSocket *sock_ptr, PrrtPacket *packet, struct sockaddr_in remote) {
    PrrtPacketDataPayload *payload = packet->payload;
    prrtTimestamp_t dataTimestamp = payload->timestamp;
    sock_ptr->lastSentTimestamp = dataTimestamp;
    PrrtClock_update(&sock_ptr->clock, dataTimestamp, payload->groupRTT_us);

    PrrtPacket *copiedPacket = PrrtPacket_copy(packet);
    check(PrrtPacketTimeoutTable_insert(sock_ptr->packetTimeoutTable, copiedPacket), "Could not insert data packet.");

    prrtSequenceNumber_t seqno = packet->sequenceNumber;

    XlapTimeStampCycle(sock_ptr, ts_data_packet, seqno, SendFeedbackStart);
    check(send_feedback(sock_ptr, remote), "Sending feedback failed.");
    XlapTimeStampCycle(sock_ptr, ts_data_packet, seqno, SendFeedbackEnd);

    prrtTimestamp_t now = PrrtClock_get_prrt_time_us(&sock_ptr->clock);
    if (is_timeout(now, payload->packetTimeout_us)) {
        PrrtForwardPacketTable_test_set_is_number_relevant(sock_ptr->forwardPacketTable, packet->sequenceNumber);
        // TODO: note this as loss
        PrrtPacket_destroy(packet);
        debug(DEBUG_RECEIVER, "timeout data packet %u (%lu > %lu)", seqno, (unsigned long) now,
              (unsigned long) payload->packetTimeout_us);
    } else 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 = PrrtRepairBlockStore_get_block(sock_ptr->repairBlockStore, baseSequenceNumber);
        if (block != NULL) {
            check(PrrtBlock_insert_data_packet(block, reference), "Inserting failed");
            decode_block(sock_ptr, block);
        } else {
            if (PrrtDataStore_insert(sock_ptr->dataPacketStore, reference) == false) {
                PrrtPacket_destroy(reference);
            }
        }

        // forward to application layer
        debug(DEBUG_DATARECEIVER, "forward %u", seqno);

        XlapTimeStampCycle(sock_ptr, ts_data_packet, seqno, PrrtReturnPackage);
        Pipe_push(sock_ptr->inQueue, &packet->asListNode);
    }
    return;

    error:
    PERROR("Handling data packet failed%s.", "");
    return;
}

static void handle_redundancy_packet(PrrtSocket *socket, PrrtPacket *packet) {
    PrrtPacketRedundancyPayload *redundancyPayload = packet->payload;

    if (!PrrtForwardPacketTable_test_is_block_relevant(socket->forwardPacketTable,
                                                       redundancyPayload->baseSequenceNumber,
                                                       redundancyPayload->n)) {
        PrrtPacket_destroy(packet);
    } else {
        PrrtBlock *block = PrrtRepairBlockStore_get_block(socket->repairBlockStore,
                                                          redundancyPayload->baseSequenceNumber);
        if (block == NULL) {
            PrrtCodingParams_update(socket->codingParameters, redundancyPayload->k, redundancyPayload->n);

            block = PrrtBlock_create(socket->codingParameters, redundancyPayload->baseSequenceNumber);

            PrrtRepairBlockStore_insert(socket->repairBlockStore, block);
        }

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

        if (PrrtBlock_insert_redundancy_packet(block, packet)) {
            decode_block(socket, block);
        } else {
            PrrtPacket_destroy(packet);
        }
    }
    return;
}

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) {
        XlapTimestampPlaceholder tsph1;
        XlapTimestampPlaceholder tsph2;
        XlapTimestampPlaceholder tsph3;
        XlapTimestampPlaceholderInitialize(&tsph1);
        XlapTimestampPlaceholderInitialize(&tsph2);
        XlapTimestampPlaceholderInitialize(&tsph3);

        n = recvfrom(sock_ptr->dataSocketFd, buffer, MAX_PAYLOAD_LENGTH, 0, (struct sockaddr *) &remote, &addrlen);
        sock_ptr->lastReceivedTimestamp = PrrtClock_get_current_time_us();
        XlapTimeStampClock(&tsph1, ts_any_packet, 0, LinkReceive);
        XlapTimeStampCycle(&tsph1, ts_any_packet, 0, LinkReceive);

        PrrtPacket *packet = (PrrtPacket *) calloc(1, sizeof(PrrtPacket));
        check_mem(packet);

        XlapTimeStampCycle(&tsph2, ts_any_packet, 0, DecodeStart);
        check(PrrtPacket_decode(buffer, (uint16_t) n, packet), "Decode failed.");
        XlapTimeStampCycle(&tsph3, ts_any_packet, 0, DecodeEnd);

        prrtSequenceNumber_t seqno = packet->sequenceNumber;

        prrtPacketType_t packetType = PrrtPacket_type(packet);
        debug(DEBUG_DATARECEIVER, "received packet %d:%u", (int) packetType, seqno);
        if (packetType == PACKET_TYPE_DATA) {
            XlapTimestampPlaceholderUse(sock_ptr, ts_data_packet, seqno, &tsph1);
            XlapTimestampPlaceholderUse(sock_ptr, ts_data_packet, seqno, &tsph2);
            XlapTimestampPlaceholderUse(sock_ptr, ts_data_packet, seqno, &tsph3);

            XlapTimeStampCycle(sock_ptr, ts_data_packet, seqno, HandlePacketStart);
            handle_data_packet(sock_ptr, packet, remote);
            XlapTimeStampCycle(sock_ptr, ts_data_packet, seqno, HandlePacketEnd);
        } else if (packetType == PACKET_TYPE_REDUNDANCY) {
            XlapTimestampPlaceholderUse(sock_ptr, ts_redundancy_packet, seqno, &tsph1);
            XlapTimestampPlaceholderUse(sock_ptr, ts_redundancy_packet, seqno, &tsph2);
            XlapTimestampPlaceholderUse(sock_ptr, ts_redundancy_packet, seqno, &tsph3);

            XlapTimeStampCycle(sock_ptr, ts_redundancy_packet, seqno, HandlePacketStart);
            handle_redundancy_packet(sock_ptr, packet);
            XlapTimeStampCycle(sock_ptr, ts_redundancy_packet, seqno, HandlePacketEnd);
        } else {
            PrrtPacket_print(packet);
            PrrtPacket_destroy(packet);
        }

        PrrtSocket_cleanup(sock_ptr);
    }

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