Function sctp_common_input_processing

freebsd/netinet/sctp_input.c:5316–5695

* common input chunk processing (v4 and v6) */

 * common input chunk processing (v4 and v6)
 */
void
sctp_common_input_processing(struct mbuf **mm, int iphlen, int offset, int length,
    struct sockaddr *src, struct sockaddr *dst,
    struct sctphdr *sh, struct sctp_chunkhdr *ch,
    uint8_t compute_crc,
    uint8_t ecn_bits,
    uint8_t mflowtype, uint32_t mflowid, uint16_t fibnum,
    uint32_t vrf_id, uint16_t port)
{
	uint32_t high_tsn;
	int fwd_tsn_seen = 0, data_processed = 0;
	struct mbuf *m = *mm, *op_err;
	char msg[SCTP_DIAG_INFO_LEN];
	int un_sent;
	int cnt_ctrl_ready = 0;
	struct sctp_inpcb *inp = NULL, *inp_decr = NULL;
	struct sctp_tcb *stcb = NULL;
	struct sctp_nets *net = NULL;

	SCTP_STAT_INCR(sctps_recvdatagrams);
#ifdef SCTP_AUDITING_ENABLED
	sctp_audit_log(0xE0, 1);
	sctp_auditing(0, inp, stcb, net);
#endif
	if (compute_crc != 0) {
		uint32_t check, calc_check;

		check = sh->checksum;
		sh->checksum = 0;
		calc_check = sctp_calculate_cksum(m, iphlen);
		sh->checksum = check;
		if (calc_check != check) {
			SCTPDBG(SCTP_DEBUG_INPUT1, "Bad CSUM on SCTP packet calc_check:%x check:%x  m:%p mlen:%d iphlen:%d\n",
			    calc_check, check, (void *)m, length, iphlen);
			stcb = sctp_findassociation_addr(m, offset, src, dst,
			    sh, ch, &inp, &net, vrf_id);
#if defined(INET) || defined(INET6)
			if ((ch->chunk_type != SCTP_INITIATION) &&
			    (net != NULL) && (net->port != port)) {
				if (net->port == 0) {
					/* UDP encapsulation turned on. */
					net->mtu -= sizeof(struct udphdr);
					if (stcb->asoc.smallest_mtu > net->mtu) {
						sctp_pathmtu_adjustment(stcb, net->mtu);
					}
				} else if (port == 0) {
					/* UDP encapsulation turned off. */
					net->mtu += sizeof(struct udphdr);
					/* XXX Update smallest_mtu */
				}
				net->port = port;
			}
#endif
			if (net != NULL) {
				net->flowtype = mflowtype;
				net->flowid = mflowid;
			}
			SCTP_PROBE5(receive, NULL, stcb, m, stcb, sh);