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#include "retransmit.h"
#include <libwifi.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "transmit.h"
static pthread_mutex_t retransmitter_mutex = PTHREAD_MUTEX_INITIALIZER;
void ack_map_init(struct ack_map *map)
{
map->top = NULL;
}
void ack_map_add(struct ack_map *map, const unsigned char dst_addr[6], const unsigned char *packet, int packet_size)
{
struct ack_map_node *cur = map->top;
struct ack_map_node *prev = NULL;
while (cur != NULL)
{
prev = cur;
cur = cur->next;
}
struct ack_map_node *next = (struct ack_map_node *)malloc(sizeof(struct ack_map_node));
next->next = NULL;
memcpy(next->dst_addr, dst_addr, 6);
next->packet = (unsigned char *)malloc(packet_size);
memcpy(next->packet, packet, packet_size);
next->packet_size = packet_size;
next->retries_left = 7;
if (prev == NULL)
{
map->top = next;
}
else
{
prev->next = next;
}
}
void ack_map_pop(struct ack_map *map)
{
if (map->top != NULL)
{
struct ack_map_node *cur = map->top;
map->top = cur->next;
free(cur->packet);
free(cur);
}
}
int ack_map_length(struct ack_map *map)
{
int result = 0;
struct ack_map_node *cur = map->top;
while (cur != NULL)
{
result++;
cur = cur->next;
}
return result;
}
void ack_map_clear(struct ack_map *map)
{
while (map->top != NULL)
{
ack_map_pop(map);
}
}
void *retransmit_thread(void *arg)
{
struct retransmitter *retransmitter = (struct retransmitter *)arg;
for (;;)
{
pthread_mutex_lock(&retransmitter_mutex);
if (retransmitter->quit)
{
pthread_mutex_unlock(&retransmitter_mutex);
break;
}
struct ack_map_node *cur = retransmitter->messages.top;
if (cur != NULL)
{
send_packet_with_radiotap(retransmitter->sock, retransmitter->device_index, cur->dst_addr, cur->packet, cur->packet_size);
// Set retransmit flag for future.
cur->packet[1] |= (1 << 3);
cur->retries_left--;
if (cur->retries_left <= 0)
{
ack_map_pop(&retransmitter->messages);
}
}
pthread_mutex_unlock(&retransmitter_mutex);
usleep(5000);
}
return NULL;
}
struct retransmitter *start_retransmit_thread(int sock, int device_index)
{
struct retransmitter *retransmitter = (struct retransmitter *)malloc(sizeof(struct retransmitter));
retransmitter->sock = sock;
retransmitter->device_index = device_index;
ack_map_init(&retransmitter->messages);
retransmitter->quit = false;
pthread_create(&retransmitter->thread_id, NULL, &retransmit_thread, retransmitter);
return retransmitter;
}
void send_until_acked(struct retransmitter *retransmitter, const unsigned char dst_addr[6], const unsigned char *packet, int packet_size)
{
pthread_mutex_lock(&retransmitter_mutex);
ack_map_add(&retransmitter->messages, dst_addr, packet, packet_size);
printf("Adding message for " MACSTR ". Current length: %d\n", MAC2STR(dst_addr), ack_map_length(&retransmitter->messages));
pthread_mutex_unlock(&retransmitter_mutex);
}
void handle_ack(struct retransmitter *retransmitter)
{
pthread_mutex_lock(&retransmitter_mutex);
if (retransmitter->messages.top != NULL)
{
retransmitter->messages.top->retries_left = 0;
}
printf("Received ACK. Current length: %d\n", ack_map_length(&retransmitter->messages));
pthread_mutex_unlock(&retransmitter_mutex);
}
void free_retransmitter(struct retransmitter *retransmitter)
{
pthread_mutex_lock(&retransmitter_mutex);
retransmitter->quit = true;
pthread_mutex_unlock(&retransmitter_mutex);
pthread_join(retransmitter->thread_id, NULL);
ack_map_clear(&retransmitter->messages);
free(retransmitter);
}
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