REKEY_TIMEOUT
struct timespec expire = { .tv_sec = REKEY_TIMEOUT, .tv_nsec = 0 };
int msecs = REKEY_TIMEOUT * 1000;
t->t_handshake_last_sent.tv_sec -= (REKEY_TIMEOUT + 1);
REKEY_TIMEOUT, t->t_handshake_retries + 1);
#define MAX_TIMER_HANDSHAKES (90 / REKEY_TIMEOUT)
#define NEW_HANDSHAKE_TIMEOUT (REKEY_TIMEOUT + KEEPALIVE_TIMEOUT)