File syn_wg.h¶

#ifndef SYN_WG_H
#define SYN_WG_H

#if __has_include("syn_config.h")
#include "syn_config.h"
#endif

#if !defined(SYN_USE_WG) || SYN_USE_WG

#include "../common/syn_defs.h"
#include "../port/syn_port_socket.h"
#include "../pt/syn_pt.h"
#include "../sched/syn_task.h"
#include "syn_sntp.h"

#include <stdbool.h>

#ifdef __cplusplus
extern "C" {
#endif

/* ── Constants ──────────────────────────────────────────────────────────── */

#ifndef SYN_WG_MTU
#define SYN_WG_MTU 1420
#endif

#define SYN_WG_TRANSPORT_OVERHEAD 32

#define SYN_WG_REKEY_AFTER_TIME 120  
#define SYN_WG_REJECT_AFTER_TIME 180 
#define SYN_WG_REKEY_TIMEOUT 5       
#define SYN_WG_KEEPALIVE_TIMEOUT 10  
#define SYN_WG_MSG_INITIATION 1 
#define SYN_WG_MSG_RESPONSE 2   
#define SYN_WG_MSG_COOKIE 3     
#define SYN_WG_MSG_TRANSPORT 4  
#define SYN_WG_INITIATION_SIZE 148 
#define SYN_WG_RESPONSE_SIZE 92    
/* ── States ─────────────────────────────────────────────────────────────── */

typedef enum {
    SYN_WG_DISCONNECTED,   
    SYN_WG_HANDSHAKE_INIT, 
    SYN_WG_ESTABLISHED,    
} SYN_WgState;

/* ── Configuration ──────────────────────────────────────────────────────── */

typedef struct {
    uint8_t private_key[32];       
    uint8_t peer_public_key[32];   
    uint8_t preshared_key[32];     
    SYN_SockAddr endpoint;         
    uint16_t keepalive_interval_s; 
} SYN_WgConfig;

/* ── Session keys ───────────────────────────────────────────────────────── */

typedef struct {
    uint8_t send_key[32];    
    uint8_t recv_key[32];    
    uint64_t send_counter;   
    uint64_t recv_counter;   
    uint32_t recv_bitmap;    
    uint32_t sender_index;   
    uint32_t receiver_index; 
    uint32_t established_ms; 
} SYN_WgSession;

/* ── Client context ─────────────────────────────────────────────────────── */

typedef struct {
    SYN_WgConfig config; 
    SYN_WgState state;   
    SYN_Socket udp_sock; 
    /* Time source */
    SYN_SNTP *sntp; 
    /* Derived keys (computed once at init from config) */
    uint8_t public_key[32]; 
    /* Active session */
    SYN_WgSession session; 
    /* Handshake state (scratch — only valid during handshake) */
    uint8_t hs_ephemeral_priv[32]; 
    uint8_t hs_chaining_key[32];   
    uint8_t hs_hash[32];           
    /* Timers */
    uint32_t last_sent_ms;      
    uint32_t last_recv_ms;      
    uint32_t last_handshake_ms; 
    /* Caller-owned I/O buffers */
    uint8_t *rx_buf;    
    size_t rx_buf_size; 
    uint8_t *tx_buf;    
    size_t tx_buf_size; 
    void (*on_recv)(const uint8_t *ip_packet, size_t len, void *ctx);
    void *user_ctx; 
} SYN_WG;

/* ── API ────────────────────────────────────────────────────────────────── */

void syn_wg_init(SYN_WG *wg, const SYN_WgConfig *config, SYN_SNTP *sntp, uint8_t *rx_buf,
                 size_t rx_buf_size, uint8_t *tx_buf, size_t tx_buf_size);

SYN_Status syn_wg_send(SYN_WG *wg, const uint8_t *ip_packet, size_t len);

SYN_PT_Status syn_wg_task(SYN_PT *pt, SYN_Task *task);

static inline bool syn_wg_is_established(const SYN_WG *wg)
{
    return wg->state == SYN_WG_ESTABLISHED;
}

typedef struct {
    uint64_t tx_bytes;          
    uint64_t rx_bytes;          
    uint32_t handshake_age_sec; 
    bool is_established;        
} SYN_WgStats;

void syn_wg_disconnect(SYN_WG *wg);

SYN_Status syn_wg_get_stats(const SYN_WG *wg, SYN_WgStats *stats);

#ifdef __cplusplus
}
#endif

#endif /* SYN_USE_WG */

#endif /* SYN_WG_H */