utun2/tests/test_etcp_simple.c

// test_etcp_simple.c - Simple test to verify ETCP sender-receiver communication
#define ETCP_DEBUG 1
#include "etcp.h"
#include "u_async.h"
#include "ll_queue.h"
#include "simple_uasync.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>

// Sender's TX callback - just forward to receiver
static void sender_tx_callback(epkt_t* epkt, uint8_t* data, uint16_t len, void* arg) {
    (void)epkt;
    epkt_t* receiver = (epkt_t*)arg;
    printf("Sender TX callback: sending %u bytes to receiver\n", len);
    
    // Forward directly to receiver (no loss, no delay)
    etcp_rx_input(receiver, data, len);
}

// Receiver's TX callback - would send ACKs back to sender in real scenario
static void receiver_tx_callback(epkt_t* epkt, uint8_t* data, uint16_t len, void* arg) {
    (void)epkt;
    (void)data;
    (void)len;
    (void)arg;
    printf("Receiver TX callback: ACK sent back\n");
}

int main(void) {
    printf("Simple ETCP sender-receiver test\n");
    
    // Initialize uasync instance
    uasync_t* ua = uasync_create();
    if (!ua) {
        fprintf(stderr, "Failed to create uasync instance\n");
        return 1;
    }
    uasync_init_instance(ua);
    
    // Create ETCP instances
    epkt_t* sender = etcp_init(ua);
    epkt_t* receiver = etcp_init(ua);
    
    if (!sender || !receiver) {
        printf("ERROR: Failed to create ETCP instances\n");
        return 1;
    }
    
    // Set up callbacks
    etcp_set_callback(sender, sender_tx_callback, receiver);
    etcp_set_callback(receiver, receiver_tx_callback, sender);
    
    // Send a simple packet
    const char* test_data = "Hello, ETCP!";
    uint16_t data_len = strlen(test_data);
    uint8_t* data = malloc(data_len);
    memcpy(data, test_data, data_len);
    
    printf("Sending test packet: %s\n", test_data);
    
    if (etcp_tx_put(sender, data, data_len) != 0) {
        printf("ERROR: Failed to queue packet\n");
        free(data);
        etcp_free(sender);
        etcp_free(receiver);
        return 1;
    }
    
    free(data); // etcp_tx_put makes its own copy
    
    // Advance time to allow transmission
    printf("Advancing time...\n");
    for (int i = 0; i < 10; i++) {
        simple_uasync_advance_time(10); // 1ms each
        // Process any timers (retransmissions, etc.)
    }
    
    // Check receiver's output queue
    ll_queue_t* output_queue = etcp_get_output_queue(receiver);
    if (!output_queue) {
        printf("ERROR: Receiver output queue is NULL\n");
        etcp_free(sender);
        etcp_free(receiver);
        return 1;
    }
    
    ll_entry_t* entry = queue_entry_get(output_queue);
    if (!entry) {
        printf("FAIL: No packet in receiver output queue\n");
        
        // Debug: check queue size
        printf("Queue size check: %d\n", queue_entry_count(output_queue));
        
        etcp_free(sender);
        etcp_free(receiver);
        return 1;
    }
    
    uint8_t* received_data = ll_entry_data(entry);
    uint16_t received_len = ll_entry_size(entry);
    
    printf("SUCCESS: Received packet of length %u\n", received_len);
    printf("Data: ");
    for (uint16_t i = 0; i < received_len; i++) {
        printf("%c", received_data[i]);
    }
    printf("\n");
    
    if (received_len == data_len && memcmp(received_data, test_data, data_len) == 0) {
        printf("PASS: Data matches!\n");
    } else {
        printf("FAIL: Data doesn't match\n");
    }
    
    queue_entry_free(entry);
    etcp_free(sender);
    etcp_free(receiver);
    uasync_destroy(ua);
    
    return 0;
}