Function sctp_process_data

freebsd/netinet/sctp_indata.c:2648–2939

}

int
sctp_process_data(struct mbuf **mm, int iphlen, int *offset, int length,
    struct sctp_inpcb *inp, struct sctp_tcb *stcb,
    struct sctp_nets *net, uint32_t *high_tsn)
{
	struct sctp_chunkhdr *ch, chunk_buf;
	struct sctp_association *asoc;
	int num_chunks = 0;	/* number of control chunks processed */
	int stop_proc = 0;
	int break_flag, last_chunk;
	int abort_flag = 0, was_a_gap;
	struct mbuf *m;
	uint32_t highest_tsn;
	uint16_t chk_length;

	/* set the rwnd */
	sctp_set_rwnd(stcb, &stcb->asoc);

	m = *mm;
	SCTP_TCB_LOCK_ASSERT(stcb);
	asoc = &stcb->asoc;
	if (SCTP_TSN_GT(asoc->highest_tsn_inside_nr_map, asoc->highest_tsn_inside_map)) {
		highest_tsn = asoc->highest_tsn_inside_nr_map;
	} else {
		highest_tsn = asoc->highest_tsn_inside_map;
	}
	was_a_gap = SCTP_TSN_GT(highest_tsn, stcb->asoc.cumulative_tsn);
	/*
	 * setup where we got the last DATA packet from for any SACK that
	 * may need to go out. Don't bump the net. This is done ONLY when a
	 * chunk is assigned.
	 */
	asoc->last_data_chunk_from = net;

	/*-
	 * Now before we proceed we must figure out if this is a wasted
	 * cluster... i.e. it is a small packet sent in and yet the driver
	 * underneath allocated a full cluster for it. If so we must copy it
	 * to a smaller mbuf and free up the cluster mbuf. This will help
	 * with cluster starvation.
	 */
	if (SCTP_BUF_LEN(m) < (long)MLEN && SCTP_BUF_NEXT(m) == NULL) {
		/* we only handle mbufs that are singletons.. not chains */
		m = sctp_get_mbuf_for_msg(SCTP_BUF_LEN(m), 0, M_NOWAIT, 1, MT_DATA);
		if (m) {
			/* ok lets see if we can copy the data up */
			caddr_t *from, *to;

			/* get the pointers and copy */
			to = mtod(m, caddr_t *);
			from = mtod((*mm), caddr_t *);
			memcpy(to, from, SCTP_BUF_LEN((*mm)));
			/* copy the length and free up the old */
			SCTP_BUF_LEN(m) = SCTP_BUF_LEN((*mm));
			sctp_m_freem(*mm);
			/* success, back copy */
			*mm = m;
		} else {