Function sctp_handle_asconf_ack

freebsd/netinet/sctp_asconf.c:1661–1848

}

void
sctp_handle_asconf_ack(struct mbuf *m, int offset,
    struct sctp_asconf_ack_chunk *cp, struct sctp_tcb *stcb,
    struct sctp_nets *net, int *abort_no_unlock)
{
	struct sctp_association *asoc;
	uint32_t serial_num;
	uint16_t ack_length;
	struct sctp_asconf_paramhdr *aph;
	struct sctp_asconf_addr *aa, *aa_next;
	uint32_t last_error_id = 0;	/* last error correlation id */
	uint32_t id;
	struct sctp_asconf_addr *ap;

	/* asconf param buffer */
	uint8_t aparam_buf[SCTP_PARAM_BUFFER_SIZE];

	/* verify minimum length */
	if (ntohs(cp->ch.chunk_length) < sizeof(struct sctp_asconf_ack_chunk)) {
		SCTPDBG(SCTP_DEBUG_ASCONF1,
		    "handle_asconf_ack: chunk too small = %xh\n",
		    ntohs(cp->ch.chunk_length));
		return;
	}
	asoc = &stcb->asoc;
	serial_num = ntohl(cp->serial_number);

	/*
	 * NOTE: we may want to handle this differently- currently, we will
	 * abort when we get an ack for the expected serial number + 1 (eg.
	 * we didn't send it), process an ack normally if it is the expected
	 * serial number, and re-send the previous ack for *ALL* other
	 * serial numbers
	 */

	/*
	 * if the serial number is the next expected, but I didn't send it,
	 * abort the asoc, since someone probably just hijacked us...
	 */
	if (serial_num == (asoc->asconf_seq_out + 1)) {
		struct mbuf *op_err;
		char msg[SCTP_DIAG_INFO_LEN];

		SCTPDBG(SCTP_DEBUG_ASCONF1, "handle_asconf_ack: got unexpected next serial number! Aborting asoc!\n");
		SCTP_SNPRINTF(msg, sizeof(msg), "Never sent serial number %8.8x", serial_num);
		op_err = sctp_generate_cause(SCTP_CAUSE_PROTOCOL_VIOLATION, msg);
		sctp_abort_an_association(stcb->sctp_ep, stcb, op_err, SCTP_SO_NOT_LOCKED);
		*abort_no_unlock = 1;
		return;
	}
	if (serial_num != asoc->asconf_seq_out_acked + 1) {
		/* got a duplicate/unexpected ASCONF-ACK */
		SCTPDBG(SCTP_DEBUG_ASCONF1, "handle_asconf_ack: got duplicate/unexpected serial number = %xh (expected = %xh)\n",
		    serial_num, asoc->asconf_seq_out_acked + 1);
		return;
	}

	if (serial_num == asoc->asconf_seq_out - 1) {