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/*
* Copyright (c) 2017-2019 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <parc/assert/parc_Assert.h>
#include <parc/logging/parc_LogReporterTextStdout.h>
#include <src/core/connection.h>
#include <src/core/forwarder.h>
#include <src/core/wldr.h>
#include <stdint.h>
#include <stdio.h>
struct wldr_buffer {
Message *message;
uint8_t rtx_counter;
};
typedef struct wldr_buffer WldrBuffer;
struct wldr_state {
uint16_t expected_label;
uint16_t next_label;
WldrBuffer *buffer[BUFFER_SIZE];
};
Wldr *wldr_Init() {
Wldr *wldr = parcMemory_AllocateAndClear(sizeof(Wldr));
parcAssertNotNull(wldr, "parcMemory_AllocateAndClear(%zu) returned NULL",
sizeof(Wldr));
wldr->expected_label = 1;
wldr->next_label = 1;
for (int i = 0; i < BUFFER_SIZE; i++) {
WldrBuffer *entry = parcMemory_AllocateAndClear(sizeof(WldrBuffer));
parcAssertNotNull(
entry,
"WldrBuffer init: parcMemory_AllocateAndClear(%zu) returned NULL",
sizeof(WldrBuffer));
entry->message = NULL;
entry->rtx_counter = 0;
wldr->buffer[i] = entry;
}
return wldr;
}
void wldr_ResetState(Wldr *wldr) {
wldr->expected_label = 1;
wldr->next_label = 1;
for (int i = 0; i < BUFFER_SIZE; i++) {
wldr->buffer[i]->message = NULL;
wldr->buffer[i]->rtx_counter = 0;
}
}
void wldr_Destroy(Wldr **wldrPtr) {
Wldr *wldr = *wldrPtr;
for (unsigned i = 0; i < BUFFER_SIZE; i++) {
if (wldr->buffer[i]->message != NULL) {
message_Release(&(wldr->buffer[i]->message));
parcMemory_Deallocate((void **)&(wldr->buffer[i]));
}
}
parcMemory_Deallocate((void **)&wldr);
*wldrPtr = NULL;
}
static void _wldr_RetransmitPacket(Wldr *wldr, const Connection *conn,
uint16_t label) {
if (wldr->buffer[label % BUFFER_SIZE]->message == NULL) {
// the required message for retransmission is not in the buffer
return;
}
if (wldr->buffer[label % BUFFER_SIZE]->rtx_counter < MAX_RTX) {
Message *msg = wldr->buffer[label % BUFFER_SIZE]->message;
message_SetWldrLabel(msg, wldr->next_label);
if (wldr->buffer[wldr->next_label % BUFFER_SIZE]->message != NULL) {
message_Release(&(wldr->buffer[wldr->next_label % BUFFER_SIZE]->message));
}
wldr->buffer[wldr->next_label % BUFFER_SIZE]->message = msg;
wldr->buffer[wldr->next_label % BUFFER_SIZE]->rtx_counter =
wldr->buffer[label % BUFFER_SIZE]->rtx_counter + 1;
message_Acquire(wldr->buffer[wldr->next_label % BUFFER_SIZE]->message);
wldr->next_label++;
connection_ReSend(conn, msg, false);
}
}
static void _wldr_SendWldrNotificaiton(Wldr *wldr, const Connection *conn,
Message *message, uint16_t expected_lbl,
uint16_t received_lbl) {
// here we need to create a new packet that is used to send the wldr
// notification to the prevoius hop. the destionation address of the
// notification is the source address of the message for which we want to
// create a notification. in fact, if message is an interest the prevoius hop
// is identified by the src. if message is a data, we need to send the
// notification message with the content name has a source address in this way
// the message will be trapped by the pounting rules in the next hop We define
// the notification as an interest message so that the NAT in the send
// function will set the src address of the local connection. Notice that in
// this way the notification packet will be dispaced to the right connection
// at the next hop.
Message *notification =
message_CreateWldrNotification(message, expected_lbl, received_lbl);
parcAssertNotNull(notification, "Got null from CreateWldrNotification");
connection_ReSend(conn, notification, true);
}
void wldr_SetLabel(Wldr *wldr, Message *message) {
// in this function we send the packet for the first time
// 1) we set the wldr label
message_SetWldrLabel(message, wldr->next_label);
// 2) we store the pointer to packet in the buffer
if (wldr->buffer[wldr->next_label % BUFFER_SIZE]->message != NULL) {
// release an old message if necessary
message_Release(&(wldr->buffer[wldr->next_label % BUFFER_SIZE]->message));
}
// we need to acquire the message to avoid that it gets destroyed
message_Acquire(message);
wldr->buffer[wldr->next_label % BUFFER_SIZE]->message = message;
wldr->buffer[wldr->next_label % BUFFER_SIZE]->rtx_counter = 0;
wldr->next_label++;
if (wldr->next_label ==
0) // we alwasy skip label 0 beacause it means that wldr is not active
wldr->next_label++;
}
void wldr_DetectLosses(Wldr *wldr, const Connection *conn, Message *message) {
if (message_HasWldr(message)) {
// this is a normal wldr packet
uint16_t pkt_lbl = (uint16_t)message_GetWldrLabel(message);
if (pkt_lbl != wldr->expected_label) {
// if the received packet label is 1 and the expected packet label >
// pkt_lbl usually we are in the case where a remote note disconnected for
// a while and reconnected on this same connection, so the two nodes are
// out of synch for this reason we do not send any notification, we just
// synch the labels
if ((pkt_lbl != 1) || (wldr->expected_label < pkt_lbl)) {
_wldr_SendWldrNotificaiton(wldr, conn, message, wldr->expected_label,
pkt_lbl);
}
// here we always synch
wldr->expected_label = (uint16_t)(pkt_lbl + 1);
} else {
wldr->expected_label++;
if (wldr->expected_label == 0)
wldr->expected_label++; // for the next_label we want to skip 0
}
}
}
void wldr_HandleWldrNotification(Wldr *wldr, const Connection *conn,
Message *message) {
uint16_t expected_lbl = (uint16_t)message_GetWldrExpectedLabel(message);
uint16_t received_lbl = (uint16_t)message_GetWldrLastReceived(message);
if ((wldr->next_label - expected_lbl) > BUFFER_SIZE) {
// the packets are not in the buffer anymore
return;
}
while (expected_lbl < received_lbl) {
_wldr_RetransmitPacket(wldr, conn, expected_lbl);
expected_lbl++;
}
}
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