Extract channel state information

src/prrt/CMakeLists.txt

-add_library(PRRT ../defines.h socket.c block.c block.h packet.c packet.h receiver.c receiver.h clock.c clock.h processes/feedback_receiver.c processes/feedback_receiver.h processes/data_transmitter.c processes/data_transmitter.h coding_params.c coding_params.h vdmcode/block_code.c vdmcode/block_code.h coding_params.c coding_params.h stores/forward_packet_table.c stores/forward_packet_table.h processes/data_receiver.c processes/data_receiver.h)
\ No newline at end of file
+add_library(PRRT ../defines.h socket.c block.c block.h packet.c packet.h receiver.c receiver.h clock.c clock.h channelStateInformation.c channelStateInformation.h processes/feedback_receiver.c processes/feedback_receiver.h processes/data_transmitter.c processes/data_transmitter.h coding_params.c coding_params.h vdmcode/block_code.c vdmcode/block_code.h coding_params.c coding_params.h stores/forward_packet_table.c stores/forward_packet_table.h processes/data_receiver.c processes/data_receiver.h)
\ No newline at end of file

src/prrt/channelStateInformation.c

+#include <stdlib.h>
+#include "../defines.h"
+#include "../util/common.h"
+#include "../util/dbg.h"
+#include "channelStateInformation.h"
+
+void PrrtChannelStateInformation_init(PrrtChannelStateInformation *csi)
+{
+    check(csi != NULL, "Input should not be NULL.");
+
+    csi->rttMean = 0;
+    csi->rttDev = 0;
+    return;
+
+    error:
+    PERROR("Should not happen.%s","");
+}
+
+void PrrtChannelStateInformation_update_rtt(PrrtChannelStateInformation *csi, uint32_t rtt)
+{
+    int32_t delta = rtt - csi->rttMean;
+// TODO: ensure that there are no arithemtic problems via rounding etc.
+    csi->rttMean = (uint32_t) (csi->rttMean + RRT_ALPHA * delta);
+    csi->rttDev = (uint32_t) (csi->rttDev + RRT_ALPHA * (labs(delta) - csi->rttDev));
+}
+
+void PrrtChannelStateInformation_print(PrrtChannelStateInformation *csi)
+{
+    check(csi != NULL, "Input should not be NULL.");
+    printf("RTT [us]: %d +- %d\n", csi->rttMean, csi->rttDev);
+
+    return;
+    error:
+    PERROR("Should not happen.%s","");
+}
\ No newline at end of file

src/prrt/channelStateInformation.h

+#ifndef PRRT_CHANNELSTATEINFORMATION_H
+#define PRRT_CHANNELSTATEINFORMATION_H
+
+#include <stdint.h>
+
+typedef struct prrtChannelStateInformation {
+    uint32_t rttMean;
+    uint32_t rttDev;
+} PrrtChannelStateInformation;
+
+void PrrtChannelStateInformation_init(PrrtChannelStateInformation* csi);
+void PrrtChannelStateInformation_update_rtt(PrrtChannelStateInformation* csi, uint32_t rtt);
+
+void PrrtChannelStateInformation_print(PrrtChannelStateInformation *csi);
+
+#endif //PRRT_CHANNELSTATEINFORMATION_H

src/prrt/socket.c

@@ -26,8 +26,7 @@ PrrtSocket* PrrtSocket_create(const uint16_t port, const uint8_t is_sender) {
     sock_ptr->sequenceNumberSource = 1;
     sock_ptr->sequenceNumberRedundancy = 1;
 
-    sock_ptr->rttMean = 0;
-    sock_ptr->rttDev = 0;
+    PrrtChannelStateInformation_init(&sock_ptr->csi);
 
     sock_ptr->dataStore = NULL;
 
@@ -256,7 +255,7 @@ int PrrtSocket_close(PrrtSocket *sock_ptr) {
         return -1;
 }
 
-PrrtPacket *PrrtSocket_recv_feedback(PrrtSocket *sock_ptr, const size_t length)
+PrrtPacket *PrrtSocket_recv_feedback(PrrtSocket *prrtSocket, const size_t length)
 {
     char bufin[MAX_PAYLOAD_LENGTH];
     ssize_t n;
@@ -265,7 +264,7 @@ PrrtPacket *PrrtSocket_recv_feedback(PrrtSocket *sock_ptr, const size_t length)
 
     struct pollfd fds;
     int timeout_msecs = 1000;
-    fds.fd = sock_ptr->feedbackSocketFd;
+    fds.fd = prrtSocket->feedbackSocketFd;
     fds.events = POLLIN;
 
     n = poll(&fds, 1, timeout_msecs);
@@ -273,22 +272,19 @@ PrrtPacket *PrrtSocket_recv_feedback(PrrtSocket *sock_ptr, const size_t length)
     if (n == 0) {
         return NULL;
     }
-    uint32_t receive_time = PrrtClock_get_current_time();
+    uint32_t receiveTime = PrrtClock_get_current_time();
 
-    n = recvfrom(sock_ptr->feedbackSocketFd, bufin, length, 0, (struct sockaddr *) &remote, &addrlen);
+    n = recvfrom(prrtSocket->feedbackSocketFd, bufin, length, 0, (struct sockaddr *) &remote, &addrlen);
     check(n >= 0, "Receiving feedback failed.");
 
-    PrrtPacket *packet_ptr = calloc(1, sizeof(PrrtPacket));
-    check_mem(packet_ptr);
-    PrrtPacket_decode(bufin, (uint16_t) n, packet_ptr);
+    PrrtPacket *prrtPacket = calloc(1, sizeof(PrrtPacket));
+    check_mem(prrtPacket);
+    PrrtPacket_decode(bufin, (uint16_t) n, prrtPacket);
 
-    PrrtPacketFeedbackPayload* feedbackPayload = packet_ptr->payload;
-    int32_t delta = (receive_time - feedbackPayload->forward_trip_timestamp) - sock_ptr->rttMean;
-    // TODO: ensure that there are no arithemtic problems via rounding etc.
-    sock_ptr->rttMean = (uint32_t) (sock_ptr->rttMean + RRT_ALPHA * delta);
-    sock_ptr->rttDev = (uint32_t) (sock_ptr->rttDev + RRT_ALPHA * (labs(delta) - sock_ptr->rttDev));
+    uint32_t forwardTripTimestamp = ((PrrtPacketFeedbackPayload*) prrtPacket->payload)->forward_trip_timestamp;
+    PrrtChannelStateInformation_update_rtt(&prrtSocket->csi, receiveTime - forwardTripTimestamp);
 
-    return packet_ptr;
+    return prrtPacket;
 
     error:
     return NULL;

src/prrt/socket.h

@@ -6,6 +6,7 @@
 #include "stores/forward_packet_table.h"
 #include "../util/list.h"
 #include "../util/bptree.h"
+#include "channelStateInformation.h"
 
 
 typedef struct prrtSocket {
@@ -44,6 +45,7 @@ typedef struct prrtSocket {
     uint32_t lastSentTimestamp;
     uint32_t lastReceivedTimestamp;
 
+    PrrtChannelStateInformation csi;
     uint32_t rttMean;
     uint32_t rttDev;
 } PrrtSocket;
@@ -55,6 +57,6 @@ int PrrtSocket_close(PrrtSocket *sock_ptr);
 int PrrtSocket_connect(PrrtSocket *sock_ptr, const char *host, const uint16_t port);
 int PrrtSocket_send(PrrtSocket *sock_ptr, const uint8_t *data, const size_t data_len);
 int32_t PrrtSocket_recv(PrrtSocket *sock_ptr, void *buf_ptr);
-PrrtPacket *PrrtSocket_recv_feedback(PrrtSocket *sock_ptr, const size_t length);
+PrrtPacket *PrrtSocket_recv_feedback(PrrtSocket *prrtSocket, const size_t length);
 
 #endif // PRRT_SOCKET_H