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/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2018 Intel Corporation
 */

#ifndef _MISC_H_
#define _MISC_H_

/**
 * @file misc.h
 * Contains miscellaneous functions/structures/macros used internally
 * by ipsec library.
 */

/*
 * Move bad (unprocessed) mbufs beyond the good (processed) ones.
 * bad_idx[] contains the indexes of bad mbufs inside the mb[].
 */
static inline void
move_bad_mbufs(struct rte_mbuf *mb[], const uint32_t bad_idx[], uint32_t nb_mb,
	uint32_t nb_bad)
{
	uint32_t i, j, k;
	struct rte_mbuf *drb[nb_bad];

	j = 0;
	k = 0;

	/* copy bad ones into a temp place */
	for (i = 0; i != nb_mb; i++) {
		if (j != nb_bad && i == bad_idx[j])
			drb[j++] = mb[i];
		else
			mb[k++] = mb[i];
	}

	/* copy bad ones after the good ones */
	for (i = 0; i != nb_bad; i++)
		mb[k + i] = drb[i];
}

/*
 * Find packet's segment for the specified offset.
 * ofs - at input should contain required offset, at output would contain
 * offset value within the segment.
 */
static inline struct rte_mbuf *
mbuf_get_seg_ofs(struct rte_mbuf *mb, uint32_t *ofs)
{
	uint32_t k, n, plen;
	struct rte_mbuf *ms;

	plen = mb->pkt_len;
	n = *ofs;

	if (n == plen) {
		ms = rte_pktmbuf_lastseg(mb);
		n = n + rte_pktmbuf_data_len(ms) - plen;
	} else {
		ms = mb;
		for (k = rte_pktmbuf_data_len(ms); n >= k;
				k = rte_pktmbuf_data_len(ms)) {
			ms = ms->next;
			n -= k;
		}
	}

	*ofs = n;
	return ms;
}

/*
 * Trim multi-segment packet at the specified offset, and free
 * all unused segments.
 * mb - input packet
 * ms - segment where to cut
 * ofs - offset within the *ms*
 * len - length to cut (from given offset to the end of the packet)
 * Can be used in conjunction with mbuf_get_seg_ofs():
 * ofs = new_len;
 * ms = mbuf_get_seg_ofs(mb, &ofs);
 * mbuf_cut_seg_ofs(mb, ms, ofs, mb->pkt_len - new_len);
 */
static inline void
mbuf_cut_seg_ofs(struct rte_mbuf *mb, struct rte_mbuf *ms, uint32_t ofs,
	uint32_t len)
{
	uint32_t n, slen;
	struct rte_mbuf *mn;

	slen = ms->data_len;
	ms->data_len = ofs;

	/* tail spawns through multiple segments */
	if (slen < ofs + len) {
		mn = ms->next;
		ms->next = NULL;
		for (n = 0; mn != NULL; n++) {
			ms = mn->next;
			rte_pktmbuf_free_seg(mn);
			mn = ms;
		}
		mb->nb_segs -= n;
	}

	mb->pkt_len -= len;
}

#endif /* _MISC_H_ */