/* * For OUTBOUND packet having a socket. Searching SPD for packet, * and return a pointer to SP. * OUT: NULL: no apropreate SP found, the following value is set to error. * 0 : bypass * EACCES : discard packet. * ENOENT : ipsec_acquire() in progress, maybe. * others : error occurred. * others: a pointer to SP * * NOTE: IPv6 mapped address concern is implemented here. */