utun2/src/conn_mgr.h

#ifndef CONN_MGR_H
#define CONN_MGR_H

#include <stdint.h>
#include <stddef.h>
#include "../lib/ll_queue.h"
#include "etcp_api.h"
#include "etcp_router.h"
#include "route_node.h"

struct UTUN_INSTANCE;
struct ETCP_CONN;
struct NODEINFO_Q;
struct ROUTE_BGP;

#define CONN_MGR_MAX_CANDIDATES        3
#define CONN_MGR_CANDIDATE_CACHE_MS 20000
#define CONN_MGR_CANDIDATE_STALE_TB 300000
#define CONN_MGR_CANDIDATE_PING_TB  20000
#define CONN_MGR_BG_PING_INTERVAL_TB    1000
#define CONN_MGR_BG_PING_CYCLE_MIN_TB   100000
#define CONN_MGR_IDLE_CHECK_INTERVAL_TB 10000
#define CONN_MGR_LOCAL_SCAN_ATTEMPTS    3
#define CONN_MGR_LOCAL_SCAN_TIMEOUT_MS  100
#define CONN_MGR_CONNECT_DIRECT_TIMEOUT_MS  5000
#define CONN_MGR_CONNECT_REVERSE_TIMEOUT_MS 15000
#define CONN_MGR_INTERM_EXCHANGE_TIMEOUT_MS 15000

#define CONN_MGR_OK                0
#define CONN_MGR_ERR_NOT_FOUND    -1
#define CONN_MGR_ERR_NO_ADDRESSES -2
#define CONN_MGR_ERR_TIMEOUT      -3
#define CONN_MGR_ERR_UNREACHABLE  -4
#define CONN_MGR_ERR_REFUSED      -5
#define CONN_MGR_ERR_ALREADY_CONNECTED -6
#define CONN_MGR_ERR_INTERNAL     -7

enum CONN_MGR_STATE {
    CONN_MGR_STATE_DISCONNECTED = 0,
    CONN_MGR_STATE_CONNECTING   = 1,
    CONN_MGR_STATE_CONNECTED    = 2,
};

enum CM_TRY_STATE {
    CM_TRY_NONE    = 0,
    CM_TRY_PENDING = 1,
    CM_TRY_OK      = 2,
    CM_TRY_FAILED  = 3,
};

#define CONN_MGR_SUBCMD_DIRECT_REQ           0x01
#define CONN_MGR_SUBCMD_DIRECT_RESP          0x02
#define CONN_MGR_SUBCMD_INTERM_EXCHANGE_REQ  0x03
#define CONN_MGR_SUBCMD_INTERM_EXCHANGE_RESP 0x04
#define CONN_MGR_SUBCMD_INTERM_SELECTED      0x05
#define CONN_MGR_SUBCMD_DISCONNECT           0x06

struct CONN_MGR_CANDIDATE {
    uint64_t node_id;
    uint16_t rtt;
} __attribute__((packed));

#pragma pack(push, 1)
struct CONN_MGR_DIRECT_REQ {
    uint8_t  cmd;
    uint8_t  subcmd;
    uint32_t request_id;
    uint8_t  addr_count;
};

struct CONN_MGR_DIRECT_RESP {
    uint8_t  cmd;
    uint8_t  subcmd;
    uint32_t request_id;
    uint8_t  accepted;
};

struct CONN_MGR_INTERM_EXCHANGE_REQ {
    uint8_t  cmd;
    uint8_t  subcmd;
    uint32_t request_id;
    uint8_t  candidate_count;
    struct   CONN_MGR_CANDIDATE candidates[4];
};

struct CONN_MGR_INTERM_EXCHANGE_RESP {
    uint8_t  cmd;
    uint8_t  subcmd;
    uint32_t request_id;
    uint8_t  my_count;
    uint8_t  your_count;
    struct   CONN_MGR_CANDIDATE my_candidates[4];
    struct   CONN_MGR_CANDIDATE your_candidates[4];
};

struct CONN_MGR_INTERM_SELECTED {
    uint8_t  cmd;
    uint8_t  subcmd;
    uint32_t request_id;
    uint8_t  count;
    struct   CONN_MGR_CANDIDATE selected[3];
};

struct CONN_MGR_DISCONNECT {
    uint8_t  cmd;
    uint8_t  subcmd;
    uint64_t node_id;
};
#pragma pack(pop)

#define CONN_MGR_DIRECT_REQ_HDR_SIZE      sizeof(struct CONN_MGR_DIRECT_REQ)
#define CONN_MGR_DIRECT_RESP_HDR_SIZE     sizeof(struct CONN_MGR_DIRECT_RESP)
#define CONN_MGR_INTERM_EXCHANGE_REQ_SIZE sizeof(struct CONN_MGR_INTERM_EXCHANGE_REQ)
#define CONN_MGR_INTERM_EXCHANGE_RESP_SIZE sizeof(struct CONN_MGR_INTERM_EXCHANGE_RESP)
#define CONN_MGR_INTERM_SELECTED_SIZE     sizeof(struct CONN_MGR_INTERM_SELECTED)
#define CONN_MGR_DISCONNECT_SIZE          sizeof(struct CONN_MGR_DISCONNECT)

typedef void (*conn_mgr_connect_callback_t)(int result, uint64_t node_id, void* arg);

struct cm_cb_node {
    conn_mgr_connect_callback_t cb;
    void* arg;
    struct cm_cb_node* next;
};

struct CONN_MGR_ENTRY {
    uint64_t node_id;
    uint8_t  state;
    uint8_t  conn_type;
    uint8_t  alien;
    uint32_t idle_timeout_ms;
    uint64_t last_traffic_tb;
    void*    idle_timer;

    struct cm_cb_node* cb_list;

    uint64_t intermediaries[CONN_MGR_MAX_INTERMEDIARIES];
    uint8_t  intermediariy_count;
    uint8_t  rr_idx;

    uint8_t  local_scan_state;
    uint8_t  main_connect_state;
    struct {
        uint8_t  phase;
        void*    timer;
        uint32_t request_id;
        void*    conn_ctx;
    } main;

    struct CONN_MGR* mgr;
};

struct CONN_MGR {
    struct UTUN_INSTANCE* instance;
    struct CONN_MGR_ENTRY* entries;
    size_t entry_count;
    size_t entry_capacity;

    void*    bg_ping_timer;
    size_t   bg_ping_cursor;
    uint64_t bg_ping_cycle_start_tb;

    void*    candidate_ping_timer;

    struct CONN_MGR_CANDIDATE best_candidates[CONN_MGR_MAX_CANDIDATES];
    uint8_t  best_candidate_count;

    uint32_t next_request_id;
    uint8_t  initialized;

    struct cm_reverse_pending* reverse_pending;
    struct cm_exchange_pending* exchange_pending;
};

struct CONN_MGR* conn_mgr_init(struct UTUN_INSTANCE* instance);
void             conn_mgr_destroy(struct CONN_MGR* mgr);

int  conn_mgr_connect_node(struct CONN_MGR* mgr, uint64_t node_id,
                           uint32_t idle_timeout_ms,
                           conn_mgr_connect_callback_t cb, void* cb_arg);
int  conn_mgr_disconnect_node(struct CONN_MGR* mgr, uint64_t node_id);
int  conn_mgr_set_idle_timeout(struct CONN_MGR* mgr, uint64_t node_id, uint32_t timeout_ms);
int  conn_mgr_get_status(struct CONN_MGR* mgr, uint64_t node_id,
                         uint8_t* out_state, uint8_t* out_conn_type);
int  conn_mgr_add_alien_node(struct CONN_MGR* mgr, const uint8_t* nodeinfo_data, size_t len);
int  conn_mgr_send(struct CONN_MGR* mgr, uint64_t node_id, struct ll_entry* entry);

void conn_mgr_update_best_candidates(struct CONN_MGR* mgr, uint64_t node_id, uint16_t rtt);

#endif