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

#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdint.h>
#include <unistd.h>
#include <inttypes.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/queue.h>

#include <rte_common.h>
#include <rte_byteorder.h>
#include <rte_malloc.h>
#include <rte_log.h>
#include <rte_debug.h>
#include <rte_cycles.h>
#include <rte_eal.h>
#include <rte_per_lcore.h>
#include <rte_lcore.h>
#include <rte_atomic.h>
#include <rte_mbuf.h>
#include <rte_ethdev.h>

#include <rte_bpf_ethdev.h>
#include "bpf_impl.h"

/*
 * information about installed BPF rx/tx callback
 */

struct bpf_eth_cbi {
	/* used by both data & control path */
	uint32_t use;    /*usage counter */
	const struct rte_eth_rxtx_callback *cb;  /* callback handle */
	struct rte_bpf *bpf;
	struct rte_bpf_jit jit;
	/* used by control path only */
	LIST_ENTRY(bpf_eth_cbi) link;
	uint16_t port;
	uint16_t queue;
} __rte_cache_aligned;

/*
 * Odd number means that callback is used by datapath.
 * Even number means that callback is not used by datapath.
 */
#define BPF_ETH_CBI_INUSE  1

/*
 * List to manage RX/TX installed callbacks.
 */
LIST_HEAD(bpf_eth_cbi_list, bpf_eth_cbi);

enum {
	BPF_ETH_RX,
	BPF_ETH_TX,
	BPF_ETH_NUM,
};

/*
 * information about all installed BPF rx/tx callbacks
 */
struct bpf_eth_cbh {
	rte_spinlock_t lock;
	struct bpf_eth_cbi_list list;
	uint32_t type;
};

static struct bpf_eth_cbh rx_cbh = {
	.lock = RTE_SPINLOCK_INITIALIZER,
	.list = LIST_HEAD_INITIALIZER(list),
	.type = BPF_ETH_RX,
};

static struct bpf_eth_cbh tx_cbh = {
	.lock = RTE_SPINLOCK_INITIALIZER,
	.list = LIST_HEAD_INITIALIZER(list),
	.type = BPF_ETH_TX,
};

/*
 * Marks given callback as used by datapath.
 */
static __rte_always_inline void
bpf_eth_cbi_inuse(struct bpf_eth_cbi *cbi)
{
	cbi->use++;
	/* make sure no store/load reordering could happen */
	rte_smp_mb();
}

/*
 * Marks given callback list as not used by datapath.
 */
static __rte_always_inline void
bpf_eth_cbi_unuse(struct bpf_eth_cbi *cbi)
{
	/* make sure all previous loads are completed */
	rte_smp_rmb();
	cbi->use++;
}

/*
 * Waits till datapath finished using given callback.
 */
static void
bpf_eth_cbi_wait(const struct bpf_eth_cbi *cbi)
{
	uint32_t nuse, puse;

	/* make sure all previous loads and stores are completed */
	rte_smp_mb();

	puse = cbi->use;

	/* in use, busy wait till current RX/TX iteration is finished */
	if ((puse & BPF_ETH_CBI_INUSE) != 0) {
		do {
			rte_pause();
			rte_compiler_barrier();
			nuse = cbi->use;
		} while (nuse == puse);
	}
}

static void
bpf_eth_cbi_cleanup(struct bpf_eth_cbi *bc)
{
	bc->bpf = NULL;
	memset(&bc->jit, 0, sizeof(bc->jit));
}

static struct bpf_eth_cbi *
bpf_eth_cbh_find(struct bpf_eth_cbh *cbh, uint16_t port, uint16_t queue)
{
	struct bpf_eth_cbi *cbi;

	LIST_FOREACH(cbi, &cbh->list, link) {
		if (cbi->port == port && cbi->queue == queue)
			break;
	}
	return cbi;
}

static struct bpf_eth_cbi *
bpf_eth_cbh_add(struct bpf_eth_cbh *cbh, uint16_t port, uint16_t queue)
{
	struct bpf_eth_cbi *cbi;

	/* return an existing one */
	cbi = bpf_eth_cbh_find(cbh, port, queue);
	if (cbi != NULL)
		return cbi;

	cbi = rte_zmalloc(NULL, sizeof(*cbi), RTE_CACHE_LINE_SIZE);
	if (cbi != NULL) {
		cbi->port = port;
		cbi->queue = queue;
		LIST_INSERT_HEAD(&cbh->list, cbi, link);
	}
	return cbi;
}

/*
 * BPF packet processing routinies.
 */

static inline uint32_t
apply_filter(struct rte_mbuf *mb[], const uint64_t rc[], uint32_t num,
	uint32_t drop)
{
	uint32_t i, j, k;
	struct rte_mbuf *dr[num];

	for (i = 0, j = 0, k = 0; i != num; i++) {

		/* filter matches */
		if (rc[i] != 0)
			mb[j++] = mb[i];
		/* no match */
		else
			dr[k++] = mb[i];
	}

	if (drop != 0) {
		/* free filtered out mbufs */
		for (i = 0; i != k; i++)
			rte_pktmbuf_free(dr[i]);
	} else {
		/* copy filtered out mbufs beyond good ones */
		for (i = 0; i != k; i++)
			mb[j + i] = dr[i];
	}

	return j;
}

static inline uint32_t
pkt_filter_vm(const struct rte_bpf *bpf, struct rte_mbuf *mb[], uint32_t num,
	uint32_t drop)
{
	uint32_t i;
	void *dp[num];
	uint64_t rc[num];

	for (i = 0; i != num; i++)
		dp[i] = rte_pktmbuf_mtod(mb[i], void *);

	rte_bpf_exec_burst(bpf, dp, rc, num);
	return apply_filter(mb, rc, num, drop);
}

static inline uint32_t
pkt_filter_jit(const struct rte_bpf_jit *jit, struct rte_mbuf *mb[],
	uint32_t num, uint32_t drop)
{
	uint32_t i, n;
	void *dp;
	uint64_t rc[num];

	n = 0;
	for (i = 0; i != num; i++) {
		dp = rte_pktmbuf_mtod(mb[i], void *);
		rc[i] = jit->func(dp);
		n += (rc[i] == 0);
	}

	if (n != 0)
		num = apply_filter(mb, rc, num, drop);

	return num;
}

static inline uint32_t
pkt_filter_mb_vm(const struct rte_bpf *bpf, struct rte_mbuf *mb[], uint32_t num,
	uint32_t drop)
{
	uint64_t rc[num];

	rte_bpf_exec_burst(bpf, (void **)mb, rc, num);
	return apply_filter(mb, rc, num, drop);
}

static inline uint32_t
pkt_filter_mb_jit(const struct rte_bpf_jit *jit, struct rte_mbuf *mb[],
	uint32_t num, uint32_t drop)
{
	uint32_t i, n;
	uint64_t rc[num];

	n = 0;
	for (i = 0; i != num; i++) {
		rc[i] = jit->func(mb[i]);
		n += (rc[i] == 0);
	}

	if (n != 0)
		num = apply_filter(mb, rc, num, drop);

	return num;
}

/*
 * RX/TX callbacks for raw data bpf.
 */

static uint16_t
bpf_rx_callback_vm(__rte_unused uint16_t port, __rte_unused uint16_t queue,
	struct rte_mbuf *pkt[], uint16_t nb_pkts,
	__rte_unused uint16_t max_pkts, void *user_param)
{
	struct bpf_eth_cbi *cbi;
	uint16_t rc;

	cbi = user_param;

	bpf_eth_cbi_inuse(cbi);
	rc = (cbi->cb != NULL) ?
		pkt_filter_vm(cbi->bpf, pkt, nb_pkts, 1) :
		nb_pkts;
	bpf_eth_cbi_unuse(cbi);
	return rc;
}

static uint16_t
bpf_rx_callback_jit(__rte_unused uint16_t port, __rte_unused uint16_t queue,
	struct rte_mbuf *pkt[], uint16_t nb_pkts,
	__rte_unused uint16_t max_pkts, void *user_param)
{
	struct bpf_eth_cbi *cbi;
	uint16_t rc;

	cbi = user_param;
	bpf_eth_cbi_inuse(cbi);
	rc = (cbi->cb != NULL) ?
		pkt_filter_jit(&cbi->jit, pkt, nb_pkts, 1) :
		nb_pkts;
	bpf_eth_cbi_unuse(cbi);
	return rc;
}

static uint16_t
bpf_tx_callback_vm(__rte_unused uint16_t port, __rte_unused uint16_t queue,
	struct rte_mbuf *pkt[], uint16_t nb_pkts, void *user_param)
{
	struct bpf_eth_cbi *cbi;
	uint16_t rc;

	cbi = user_param;
	bpf_eth_cbi_inuse(cbi);
	rc = (cbi->cb != NULL) ?
		pkt_filter_vm(cbi->bpf, pkt, nb_pkts, 0) :
		nb_pkts;
	bpf_eth_cbi_unuse(cbi);
	return rc;
}

static uint16_t
bpf_tx_callback_jit(__rte_unused uint16_t port, __rte_unused uint16_t queue,
	struct rte_mbuf *pkt[], uint16_t nb_pkts, void *user_param)
{
	struct bpf_eth_cbi *cbi;
	uint16_t rc;

	cbi = user_param;
	bpf_eth_cbi_inuse(cbi);
	rc = (cbi->cb != NULL) ?
		pkt_filter_jit(&cbi->jit, pkt, nb_pkts, 0) :
		nb_pkts;
	bpf_eth_cbi_unuse(cbi);
	return rc;
}

/*
 * RX/TX callbacks for mbuf.
 */

static uint16_t
bpf_rx_callback_mb_vm(__rte_unused uint16_t port, __rte_unused uint16_t queue,
	struct rte_mbuf *pkt[], uint16_t nb_pkts,
	__rte_unused uint16_t max_pkts, void *user_param)
{
	struct bpf_eth_cbi *cbi;
	uint16_t rc;

	cbi = user_param;
	bpf_eth_cbi_inuse(cbi);
	rc = (cbi->cb != NULL) ?
		pkt_filter_mb_vm(cbi->bpf, pkt, nb_pkts, 1) :
		nb_pkts;
	bpf_eth_cbi_unuse(cbi);
	return rc;
}

static uint16_t
bpf_rx_callback_mb_jit(__rte_unused uint16_t port, __rte_unused uint16_t queue,
	struct rte_mbuf *pkt[], uint16_t nb_pkts,
	__rte_unused uint16_t max_pkts, void *user_param)
{
	struct bpf_eth_cbi *cbi;
	uint16_t rc;

	cbi = user_param;
	bpf_eth_cbi_inuse(cbi);
	rc = (cbi->cb != NULL) ?
		pkt_filter_mb_jit(&cbi->jit, pkt, nb_pkts, 1) :
		nb_pkts;
	bpf_eth_cbi_unuse(cbi);
	return rc;
}

static uint16_t
bpf_tx_callback_mb_vm(__rte_unused uint16_t port, __rte_unused uint16_t queue,
	struct rte_mbuf *pkt[], uint16_t nb_pkts, void *user_param)
{
	struct bpf_eth_cbi *cbi;
	uint16_t rc;

	cbi = user_param;
	bpf_eth_cbi_inuse(cbi);
	rc = (cbi->cb != NULL) ?
		pkt_filter_mb_vm(cbi->bpf, pkt, nb_pkts, 0) :
		nb_pkts;
	bpf_eth_cbi_unuse(cbi);
	return rc;
}

static uint16_t
bpf_tx_callback_mb_jit(__rte_unused uint16_t port, __rte_unused uint16_t queue,
	struct rte_mbuf *pkt[], uint16_t nb_pkts, void *user_param)
{
	struct bpf_eth_cbi *cbi;
	uint16_t rc;

	cbi = user_param;
	bpf_eth_cbi_inuse(cbi);
	rc = (cbi->cb != NULL) ?
		pkt_filter_mb_jit(&cbi->jit, pkt, nb_pkts, 0) :
		nb_pkts;
	bpf_eth_cbi_unuse(cbi);
	return rc;
}

static rte_rx_callback_fn
select_rx_callback(enum rte_bpf_arg_type type, uint32_t flags)
{
	if (flags & RTE_BPF_ETH_F_JIT) {
		if (type == RTE_BPF_ARG_PTR)
			return bpf_rx_callback_jit;
		else if (type == RTE_BPF_ARG_PTR_MBUF)
			return bpf_rx_callback_mb_jit;
	} else if (type == RTE_BPF_ARG_PTR)
		return bpf_rx_callback_vm;
	else if (type == RTE_BPF_ARG_PTR_MBUF)
		return bpf_rx_callback_mb_vm;

	return NULL;
}

static rte_tx_callback_fn
select_tx_callback(enum rte_bpf_arg_type type, uint32_t flags)
{
	if (flags & RTE_BPF_ETH_F_JIT) {
		if (type == RTE_BPF_ARG_PTR)
			return bpf_tx_callback_jit;
		else if (type == RTE_BPF_ARG_PTR_MBUF)
			return bpf_tx_callback_mb_jit;
	} else if (type == RTE_BPF_ARG_PTR)
		return bpf_tx_callback_vm;
	else if (type == RTE_BPF_ARG_PTR_MBUF)
		return bpf_tx_callback_mb_vm;

	return NULL;
}

/*
 * helper function to perform BPF unload for given port/queue.
 * have to introduce extra complexity (and possible slowdown) here,
 * as right now there is no safe generic way to remove RX/TX callback
 * while IO is active.
 * Still don't free memory allocated for callback handle itself,
 * again right now there is no safe way to do that without stopping RX/TX
 * on given port/queue first.
 */
static void
bpf_eth_cbi_unload(struct bpf_eth_cbi *bc)
{
	/* mark this cbi as empty */
	bc->cb = NULL;
	rte_smp_mb();

	/* make sure datapath doesn't use bpf anymore, then destroy bpf */
	bpf_eth_cbi_wait(bc);
	rte_bpf_destroy(bc->bpf);
	bpf_eth_cbi_cleanup(bc);
}

static void
bpf_eth_unload(struct bpf_eth_cbh *cbh, uint16_t port, uint16_t queue)
{
	struct bpf_eth_cbi *bc;

	bc = bpf_eth_cbh_find(cbh, port, queue);
	if (bc == NULL || bc->cb == NULL)
		return;

	if (cbh->type == BPF_ETH_RX)
		rte_eth_remove_rx_callback(port, queue, bc->cb);
	else
		rte_eth_remove_tx_callback(port, queue, bc->cb);

	bpf_eth_cbi_unload(bc);
}


__rte_experimental void
rte_bpf_eth_rx_unload(uint16_t port, uint16_t queue)
{
	struct bpf_eth_cbh *cbh;

	cbh = &rx_cbh;
	rte_spinlock_lock(&cbh->lock);
	bpf_eth_unload(cbh, port, queue);
	rte_spinlock_unlock(&cbh->lock);
}

__rte_experimental void
rte_bpf_eth_tx_unload(uint16_t port, uint16_t queue)
{
	struct bpf_eth_cbh *cbh;

	cbh = &tx_cbh;
	rte_spinlock_lock(&cbh->lock);
	bpf_eth_unload(cbh, port, queue);
	rte_spinlock_unlock(&cbh->lock);
}

static int
bpf_eth_elf_load(struct bpf_eth_cbh *cbh, uint16_t port, uint16_t queue,
	const struct rte_bpf_prm *prm, const char *fname, const char *sname,
	uint32_t flags)
{
	int32_t rc;
	struct bpf_eth_cbi *bc;
	struct rte_bpf *bpf;
	rte_rx_callback_fn frx;
	rte_tx_callback_fn ftx;
	struct rte_bpf_jit jit;

	frx = NULL;
	ftx = NULL;

	if (prm == NULL || rte_eth_dev_is_valid_port(port) == 0 ||
			queue >= RTE_MAX_QUEUES_PER_PORT)
		return -EINVAL;

	if (cbh->type == BPF_ETH_RX)
		frx = select_rx_callback(prm->prog_arg.type, flags);
	else
		ftx = select_tx_callback(prm->prog_arg.type, flags);

	if (frx == NULL && ftx == NULL) {
		RTE_BPF_LOG(ERR, "%s(%u, %u): no callback selected;\n",
			__func__, port, queue);
		return -EINVAL;
	}

	bpf = rte_bpf_elf_load(prm, fname, sname);
	if (bpf == NULL)
		return -rte_errno;

	rte_bpf_get_jit(bpf, &jit);

	if ((flags & RTE_BPF_ETH_F_JIT) != 0 && jit.func == NULL) {
		RTE_BPF_LOG(ERR, "%s(%u, %u): no JIT generated;\n",
			__func__, port, queue);
		rte_bpf_destroy(bpf);
		return -ENOTSUP;
	}

	/* setup/update global callback info */
	bc = bpf_eth_cbh_add(cbh, port, queue);
	if (bc == NULL)
		return -ENOMEM;

	/* remove old one, if any */
	if (bc->cb != NULL)
		bpf_eth_unload(cbh, port, queue);

	bc->bpf = bpf;
	bc->jit = jit;

	if (cbh->type == BPF_ETH_RX)
		bc->cb = rte_eth_add_rx_callback(port, queue, frx, bc);
	else
		bc->cb = rte_eth_add_tx_callback(port, queue, ftx, bc);

	if (bc->cb == NULL) {
		rc = -rte_errno;
		rte_bpf_destroy(bpf);
		bpf_eth_cbi_cleanup(bc);
	} else
		rc = 0;

	return rc;
}

__rte_experimental int
rte_bpf_eth_rx_elf_load(uint16_t port, uint16_t queue,
	const struct rte_bpf_prm *prm, const char *fname, const char *sname,
	uint32_t flags)
{
	int32_t rc;
	struct bpf_eth_cbh *cbh;

	cbh = &rx_cbh;
	rte_spinlock_lock(&cbh->lock);
	rc = bpf_eth_elf_load(cbh, port, queue, prm, fname, sname, flags);
	rte_spinlock_unlock(&cbh->lock);

	return rc;
}

__rte_experimental int
rte_bpf_eth_tx_elf_load(uint16_t port, uint16_t queue,
	const struct rte_bpf_prm *prm, const char *fname, const char *sname,
	uint32_t flags)
{
	int32_t rc;
	struct bpf_eth_cbh *cbh;

	cbh = &tx_cbh;
	rte_spinlock_lock(&cbh->lock);
	rc = bpf_eth_elf_load(cbh, port, queue, prm, fname, sname, flags);
	rte_spinlock_unlock(&cbh->lock);

	return rc;
}