OpenVPN移动性改造-靠新的session iD而不是IP/Port识别客户端

1.设备会经常由于小区或模式切换而更改IP地址。

2.移动设备存在多张3G/4G/2.75G网卡时，希望这些网卡同时收发数据。

3.经常性的失联

4.RRC相关造成的额外延时

会话层真的太重要了

OpenVPN的故事

解决问题的步骤

struct multi_instance *
multi_get_create_instance_udp (struct multi_context *m)
{
    ...
    if (mroute_extract_openvpn_sockaddr (&real, &m->top.c2.from.dest, true)) {
        struct hash_element *he;
        const uint32_t hv = hash_value (hash, &real);
        struct hash_bucket *bucket = hash_bucket (hash, hv);
 
        hash_bucket_lock (bucket);
        he = hash_lookup_fast (hash, bucket, &real, hv);

        if (he) {
            mi = (struct multi_instance *) he->value;
        } else {
            // 找不到multi_instance的异常流处理
            if (!m->top.c2.tls_auth_standalone
                 || tls_pre_decrypt_lite (m->top.c2.tls_auth_standalone, &m->top.c2.from, &m->top.c2.buf)) {
                // 异常流处理
            }
        }
...
}

m->hash = hash_init (t->options.real_hash_size,
               fake_addr_hash_function,
               fake_addr_compare_function);

uint32_t fake_addr_hash_function(const void *key, uint32_t iv)
{
    return 0x10101010;
}
bool fake_addr_compare_function(const void *key1, const void *key2)
{
    return true;
}

ASSERT (link_socket_actual_defined (c->c2.to_link_addr));

struct context_2
{
...
  struct link_socket_actual *to_link_addr;    /* IP address of remote */
  struct link_socket_actual from;               /* address of incoming datagram */
...
}

void
process_outgoing_link (struct context *c)
{
  struct gc_arena gc = gc_new ();

  perf_push (PERF_PROC_OUT_LINK);
#if 1    // 吐嘈时骂过的，实际上我经常这么玩
{
        c->c2.to_link_addr = &c->c2.from;
}
#endif
...
}

关于本文的引申

关于模拟不仿真