PDU_VER_LENGTH
if (ntohs(rpdu->length) > c - PDU_VER_LENGTH) {
ntohs(rpdu->length), (int) (c - PDU_VER_LENGTH));
ntohs(rpdu->length) + PDU_VER_LENGTH, MSG_WAITALL);
if (ntohs(t->length) + PDU_VER_LENGTH > MAX_PDU_SIZE) {
ntohs(pdu->length) + PDU_VER_LENGTH, 0);
spdu->length = htons(IPV4_HELLO_MSG_SIZE - PDU_VER_LENGTH);
spdu->length = htons(IPV6_HELLO_MSG_SIZE - PDU_VER_LENGTH);