1 // SPDX-License-Identifier: GPL-2.0-or-later
4  *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
5  *  Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
18 	return LIH_SIZE - 1 - (ctr % LIH_SIZE);  in LIH_INDEX()
24 	return lh->counter ? lh->ring[LIH_INDEX(lh->counter - 1)] : NULL;  in tfrc_lh_peek()
30 	BUG_ON(i >= lh->counter);  in tfrc_lh_get_interval()
31 	return lh->ring[LIH_INDEX(lh->counter - i - 1)]->li_length;  in tfrc_lh_get_interval()
35  *	On-demand allocation and de-allocation of entries
39 	if (lh->ring[LIH_INDEX(lh->counter)] == NULL)  in tfrc_lh_demand_next()
40 		lh->ring[LIH_INDEX(lh->counter)] = kmem_cache_alloc(tfrc_lh_slab,  in tfrc_lh_demand_next()
42 	return lh->ring[LIH_INDEX(lh->counter)];  in tfrc_lh_demand_next()
50 	for (lh->counter = 0; lh->counter < LIH_SIZE; lh->counter++)  in tfrc_lh_cleanup()
51 		if (lh->ring[LIH_INDEX(lh->counter)] != NULL) {  in tfrc_lh_cleanup()
53 					lh->ring[LIH_INDEX(lh->counter)]);  in tfrc_lh_cleanup()
54 			lh->ring[LIH_INDEX(lh->counter)] = NULL;  in tfrc_lh_cleanup()
61 	int i, k = tfrc_lh_length(lh) - 1; /* k is as in rfc3448bis, 5.4 */  in tfrc_lh_calc_i_mean()
74 			i_tot1 += i_i * tfrc_lh_weights[i-1];  in tfrc_lh_calc_i_mean()
77 	lh->i_mean = max(i_tot0, i_tot1) / w_tot;  in tfrc_lh_calc_i_mean()
81  * tfrc_lh_update_i_mean  -  Update the `open' loss interval I_0
89 	struct tfrc_loss_interval *cur = tfrc_lh_peek(lh);  in tfrc_lh_update_i_mean()  local
90 	u32 old_i_mean = lh->i_mean;  in tfrc_lh_update_i_mean()
93 	if (cur == NULL)			/* not initialised */  in tfrc_lh_update_i_mean()
96 	len = dccp_delta_seqno(cur->li_seqno, DCCP_SKB_CB(skb)->dccpd_seq) + 1;  in tfrc_lh_update_i_mean()
98 	if (len - (s64)cur->li_length <= 0)	/* duplicate or reordered */  in tfrc_lh_update_i_mean()
101 	if (SUB16(dccp_hdr(skb)->dccph_ccval, cur->li_ccval) > 4)  in tfrc_lh_update_i_mean()
105 		 * starting the current loss interval (cur) and if the modulo-16  in tfrc_lh_update_i_mean()
106 		 * distance from C(cur) to C(S) is greater than 4, consider all  in tfrc_lh_update_i_mean()
110 		cur->li_is_closed = 1;  in tfrc_lh_update_i_mean()
115 	cur->li_length = len;  in tfrc_lh_update_i_mean()
118 	return lh->i_mean < old_i_mean;  in tfrc_lh_update_i_mean()
122 static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur,  in tfrc_lh_is_new_loss()  argument
125 	return	dccp_delta_seqno(cur->li_seqno, new_loss->tfrchrx_seqno) > 0 &&  in tfrc_lh_is_new_loss()
126 		(cur->li_is_closed || SUB16(new_loss->tfrchrx_ccval, cur->li_ccval) > 4);  in tfrc_lh_is_new_loss()
130  * tfrc_lh_interval_add  -  Insert new record into the Loss Interval database
133  * @calc_first_li: Caller-dependent routine to compute length of first interval
134  * @sk:		   Used by @calc_first_li in caller-specific way (subtyping)
141 	struct tfrc_loss_interval *cur = tfrc_lh_peek(lh), *new;  in tfrc_lh_interval_add()  local
143 	if (cur != NULL && !tfrc_lh_is_new_loss(cur, tfrc_rx_hist_loss_prev(rh)))  in tfrc_lh_interval_add()
152 	new->li_seqno	  = tfrc_rx_hist_loss_prev(rh)->tfrchrx_seqno;  in tfrc_lh_interval_add()
153 	new->li_ccval	  = tfrc_rx_hist_loss_prev(rh)->tfrchrx_ccval;  in tfrc_lh_interval_add()
154 	new->li_is_closed = 0;  in tfrc_lh_interval_add()
156 	if (++lh->counter == 1)  in tfrc_lh_interval_add()
157 		lh->i_mean = new->li_length = (*calc_first_li)(sk);  in tfrc_lh_interval_add()
159 		cur->li_length = dccp_delta_seqno(cur->li_seqno, new->li_seqno);  in tfrc_lh_interval_add()
160 		new->li_length = dccp_delta_seqno(new->li_seqno,  in tfrc_lh_interval_add()
161 				  tfrc_rx_hist_last_rcv(rh)->tfrchrx_seqno) + 1;  in tfrc_lh_interval_add()
162 		if (lh->counter > (2*LIH_SIZE))  in tfrc_lh_interval_add()
163 			lh->counter -= LIH_SIZE;  in tfrc_lh_interval_add()
175 	return tfrc_lh_slab == NULL ? -ENOBUFS : 0;  in tfrc_li_init()