Function sctp_process_control

freebsd/netinet/sctp_input.c:4355–5311

 */
#ifdef __GNUC__
__attribute__((noinline))
#endif
static struct sctp_tcb *
sctp_process_control(struct mbuf *m, int iphlen, int *offset, int length,
    struct sockaddr *src, struct sockaddr *dst,
    struct sctphdr *sh, struct sctp_chunkhdr *ch, struct sctp_inpcb *inp,
    struct sctp_tcb *stcb, struct sctp_nets **netp, int *fwd_tsn_seen,
    uint8_t mflowtype, uint32_t mflowid, uint16_t fibnum,
    uint32_t vrf_id, uint16_t port)
{
	struct sctp_association *asoc;
	struct mbuf *op_err;
	char msg[SCTP_DIAG_INFO_LEN];
	uint32_t vtag_in;
	int num_chunks = 0;	/* number of control chunks processed */
	uint32_t chk_length, contiguous;
	int ret;
	int abort_no_unlock = 0;
	int ecne_seen = 0;

	/*
	 * How big should this be, and should it be alloc'd? Lets try the
	 * d-mtu-ceiling for now (2k) and that should hopefully work ...
	 * until we get into jumbo grams and such..
	 */
	uint8_t chunk_buf[SCTP_CHUNK_BUFFER_SIZE];
	int got_auth = 0;
	uint32_t auth_offset = 0, auth_len = 0;
	int auth_skipped = 0;
	int asconf_cnt = 0;

	SCTPDBG(SCTP_DEBUG_INPUT1, "sctp_process_control: iphlen=%u, offset=%u, length=%u stcb:%p\n",
	    iphlen, *offset, length, (void *)stcb);

	if (stcb) {
		SCTP_TCB_LOCK_ASSERT(stcb);
	}
	/* validate chunk header length... */
	if (ntohs(ch->chunk_length) < sizeof(*ch)) {
		SCTPDBG(SCTP_DEBUG_INPUT1, "Invalid header length %d\n",
		    ntohs(ch->chunk_length));
		*offset = length;
		return (stcb);
	}
	/*
	 * validate the verification tag
	 */
	vtag_in = ntohl(sh->v_tag);

	if (ch->chunk_type == SCTP_INITIATION) {
		SCTPDBG(SCTP_DEBUG_INPUT1, "Its an INIT of len:%d vtag:%x\n",
		    ntohs(ch->chunk_length), vtag_in);
		if (vtag_in != 0) {
			/* protocol error- silently discard... */
			SCTP_STAT_INCR(sctps_badvtag);
			if (stcb != NULL) {
				SCTP_TCB_UNLOCK(stcb);
			}