utun2/net_emulator/net_emulator.h

// net_emulator.h - Network emulator for testing utun with delay, loss, reordering
#ifndef NET_EMULATOR_H
#define NET_EMULATOR_H

#include <stdint.h>
#include <stddef.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include "u_async.h"

#ifdef __cplusplus
extern "C" {
#endif

// Maximum number of rules per endpoint
#define MAX_RULES_PER_ENDPOINT 10
#define MAX_ENDPOINTS 100
#define MAX_PACKET_SIZE 65536

// Forward declaration
typedef struct net_emulator_s net_emulator_t;

// Delay range (milliseconds)
typedef struct {
    int min_ms;
    int max_ms;
} delay_range_t;

// Rule: probability and delay
typedef struct {
    int probability_percent;  // 0-100
    delay_range_t delay;
} rule_t;

// Network endpoint configuration
typedef struct {
    struct sockaddr_in listen_addr;  // Address to listen on
    struct sockaddr_in target_addr;  // Address to forward to (port - 10000)
    rule_t rules[MAX_RULES_PER_ENDPOINT];
    int rule_count;
    int total_probability;  // Sum of probabilities (should be <= 100)
    
    // For reordering simulation
    int reorder_probability;  // Probability to reorder with next packet (0-100)
    
    // Socket descriptor
    int sockfd;
    net_emulator_t* emulator;  // Parent emulator instance
} endpoint_t;

// Main emulator state
struct net_emulator_s {
    endpoint_t endpoints[MAX_ENDPOINTS];
    int endpoint_count;
    int running;
    uasync_t* ua;  // uasync instance
};

/**
 * @brief Parse configuration file
 * @param filename Configuration file path
 * @param emulator Emulator state to fill
 * @return 0 on success, -1 on error
 */
int parse_emulator_config(const char *filename, net_emulator_t *emulator);

/**
 * @brief Initialize network emulator
 * @param emulator Emulator state
 * @return 0 on success, -1 on error
 */
int net_emulator_init(net_emulator_t *emulator);

/**
 * @brief Run network emulator main loop
 * @param emulator Emulator state
 */
void net_emulator_run(net_emulator_t *emulator);

/**
 * @brief Clean up emulator resources
 * @param emulator Emulator state
 */
void net_emulator_cleanup(net_emulator_t *emulator);

#ifdef __cplusplus
}
#endif

#endif /* NET_EMULATOR_H */