taglinefilesource code
FW_MASQUERADE111net/ipv4/ip_forward.ccase FW_MASQUERADE:
FW_MASQUERADE246net/ipv4/ip_forward.cif (!(is_frag&4) && fw_res==FW_MASQUERADE)
FW_MASQUERADE482net/ipv4/ip_fw.creturn ((f_flag&IP_FW_F_MASQ)?FW_MASQUERADE:FW_ACCEPT);