utun2/!/test_udp_socket.h

#ifndef TEST_UDP_SOCKET_H
#define TEST_UDP_SOCKET_H

#include <sys/socket.h>
#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>

#define TEST_UDP_MAX_PACKET_SIZE 65536
#define TEST_UDP_MAX_QUEUE_SIZE 1000

// Test UDP packet structure
struct test_udp_packet {
    uint8_t* data;
    size_t len;
    struct sockaddr_storage addr;
    socklen_t addr_len;
    struct test_udp_packet* next;
};

// Virtual UDP socket for testing
struct test_udp_socket {
    int fd;                             // Virtual file descriptor
    int family;                         // Address family (AF_INET or AF_INET6)
    struct sockaddr_storage local_addr;
    bool bound;
    bool nonblocking;
    
    // Receive queue (packets waiting to be read)
    struct test_udp_packet* recv_queue_head;
    struct test_udp_packet* recv_queue_tail;
    size_t recv_queue_size;
    
    // Statistics
    struct {
        size_t packets_sent;
        size_t packets_received;
        size_t bytes_sent;
        size_t bytes_received;
        size_t send_errors;
        size_t recv_errors;
    } stats;
    
    // Callback for outgoing packets
    void (*packet_sent)(const uint8_t* data, size_t len, 
                       const struct sockaddr* dest_addr, socklen_t addr_len,
                       void* context);
    
    void* context;
};

// Create virtual UDP socket
struct test_udp_socket* test_udp_socket_create(int family);

// Destroy virtual UDP socket
void test_udp_socket_destroy(struct test_udp_socket* sock);

// Bind virtual socket
int test_udp_socket_bind(struct test_udp_socket* sock, const struct sockaddr* addr, socklen_t len);

// Set socket options (limited implementation for testing)
int test_udp_socket_setsockopt(struct test_udp_socket* sock, int level, int optname, 
                              const void *optval, socklen_t optlen);

// Get socket options
int test_udp_socket_getsockopt(struct test_udp_socket* sock, int level, int optname,
                              void *optval, socklen_t *optlen);

// Set non-blocking mode
int test_udp_socket_set_nonblocking(struct test_udp_socket* sock, bool nonblocking);

// Send packet using virtual socket
ssize_t test_udp_socket_sendto(struct test_udp_socket* sock, const void *buf, size_t len, int flags,
                              const struct sockaddr *dest_addr, socklen_t addr_len);

// Receive packet from virtual socket
ssize_t test_udp_socket_recvfrom(struct test_udp_socket* sock, void *buf, size_t len, int flags,
                                struct sockaddr *src_addr, socklen_t *addr_len);

// Inject packet into receive queue (simulates incoming packet)
int test_udp_socket_inject(struct test_udp_socket* sock, 
                          const uint8_t* data, size_t len,
                          const struct sockaddr* src_addr, socklen_t addr_len);

// Get virtual socket file descriptor
int test_udp_socket_get_fd(struct test_udp_socket* sock);

// Get socket statistics
void test_udp_socket_get_stats(struct test_udp_socket* sock, size_t* packets_sent, 
                              size_t* packets_received, size_t* bytes_sent, 
                              size_t* bytes_received, size_t* send_errors, size_t* recv_errors);

// Reset socket statistics
void test_udp_socket_reset_stats(struct test_udp_socket* sock);

// Global virtual socket registry for fd-based operations
struct test_udp_socket* test_udp_socket_find_by_fd(int fd);
void test_udp_socket_register(struct test_udp_socket* sock);
void test_udp_socket_unregister(struct test_udp_socket* sock);

#endif // TEST_UDP_SOCKET_H