/*
// Copyright (c) 2010-2017 Intel Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
*/

#include <rte_ethdev.h>
#include <rte_ether.h>
#include <rte_ip.h>
#include <rte_udp.h>
#include <rte_version.h>
#if RTE_VERSION > RTE_VERSION_NUM(19,11,0,0)
#include <rte_vxlan.h>
#endif

#include "vxlangpe_nsh.h"
#include "task_base.h"
#include "tx_pkt.h"
#include "task_init.h"
#include "thread_generic.h"
#include "prefetch.h"
#include "log.h"

#define VXLAN_GPE_HDR_SZ sizeof(prox_rte_ether_hdr) + sizeof(prox_rte_ipv4_hdr) + sizeof(prox_rte_udp_hdr) + sizeof(prox_rte_vxlan_gpe_hdr) + sizeof(struct nsh_hdr)
#define ETHER_NSH_TYPE 0x4F89 /* 0x894F in little endian */
#define VXLAN_GPE_NSH_TYPE 0xB612 /* 4790 in little endian */
#define VXLAN_GPE_NP 0x4

uint16_t decap_nsh_packets(struct rte_mbuf **mbufs, uint16_t n_pkts);
uint16_t encap_nsh_packets(struct rte_mbuf **mbufs, uint16_t n_pkts);

struct task_decap_nsh {
	struct task_base base;
};

struct task_encap_nsh {
	struct task_base base;
};

static void init_task_decap_nsh(__attribute__((unused)) struct task_base *tbase,
			     __attribute__((unused)) struct task_args *targ)
{
	return;
}

static inline uint8_t handle_decap_nsh(__attribute__((unused)) struct task_decap_nsh *task, struct rte_mbuf *mbuf)
{
	prox_rte_ether_hdr *eth_hdr = NULL;
	prox_rte_udp_hdr *udp_hdr = NULL;
	prox_rte_vxlan_gpe_hdr *vxlan_gpe_hdr = NULL;
	uint16_t hdr_len;

	eth_hdr = rte_pktmbuf_mtod(mbuf, prox_rte_ether_hdr *);
	if (eth_hdr->ether_type == ETHER_NSH_TYPE) {
		/* "decapsulate" Ethernet + NSH header by moving packet pointer */
		hdr_len = sizeof(prox_rte_ether_hdr) + sizeof(struct nsh_hdr);

		mbuf->data_len = (uint16_t)(mbuf->data_len - hdr_len);
		mbuf->data_off += hdr_len;
		mbuf->pkt_len = (uint32_t)(mbuf->pkt_len - hdr_len);
		/* save length of header in reserved 16bits of rte_mbuf */
		mbuf->udata64 = hdr_len;
	}
	else {
		if (mbuf->data_len < VXLAN_GPE_HDR_SZ) {
			mbuf->udata64 = 0;
			return 0;
		}

		/* check the UDP destination port */
		udp_hdr = (prox_rte_udp_hdr *)(((unsigned char *)eth_hdr) + sizeof(prox_rte_ether_hdr) + sizeof(prox_rte_ipv4_hdr));
		if (udp_hdr->dst_port != VXLAN_GPE_NSH_TYPE) {
			mbuf->udata64 = 0;
			return 0;
		}

		/* check the Next Protocol field in VxLAN-GPE header */
		vxlan_gpe_hdr = (prox_rte_vxlan_gpe_hdr *)(((unsigned char *)eth_hdr) + sizeof(prox_rte_ether_hdr) + sizeof(prox_rte_ipv4_hdr) + sizeof(prox_rte_udp_hdr));
		if (vxlan_gpe_hdr->proto != VXLAN_GPE_NP) {
			mbuf->udata64 = 0;
			return 0;
		}

		/* "decapsulate" VxLAN-GPE + NSH header by moving packet pointer */
		hdr_len = VXLAN_GPE_HDR_SZ;

		mbuf->data_len = (uint16_t)(mbuf->data_len - hdr_len);
		mbuf->data_off += hdr_len;
		mbuf->pkt_len  = (uint32_t)(mbuf->pkt_len - hdr_len);
		/* save length of header in reserved 16bits of rte_mbuf */
		mbuf->udata64 = hdr_len;
	}

	return 0;
}

static int handle_decap_nsh_bulk(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts)
{
	struct task_decap_nsh *task = (struct task_decap_nsh *)tbase;
	uint8_t out[MAX_PKT_BURST];
	uint16_t j;

	prefetch_first(mbufs, n_pkts);
	for (j = 0; j + PREFETCH_OFFSET < n_pkts; ++j) {
#ifdef PROX_PREFETCH_OFFSET
		PREFETCH0(mbufs[j + PREFETCH_OFFSET]);
		PREFETCH0(rte_pktmbuf_mtod(mbufs[j + PREFETCH_OFFSET - 1], void *));
#endif
		out[j] = handle_decap_nsh(task, mbufs[j]);
	}
#ifdef PROX_PREFETCH_OFFSET
	PREFETCH0(rte_pktmbuf_mtod(mbufs[n_pkts - 1], void *));
	for (; j < n_pkts; ++j) {
		out[j] = handle_decap_nsh(task, mbufs[j]);
	}
#endif
	return task->base.tx_pkt(&task->base, mbufs, n_pkts, out);
}

static void init_task_encap_nsh(__attribute__((unused)) struct task_base *tbase,
			      __attribute__((unused)) struct task_args *targ)
{
	return;
}

static inline uint8_t handle_encap_nsh(__attribute__((unused)) struct task_encap_nsh *task, struct rte_mbuf *mbuf)
{
	prox_rte_ether_hdr *eth_hdr = NULL;
	struct nsh_hdr *nsh_hdr = NULL;
	prox_rte_udp_hdr *udp_hdr = NULL;
	prox_rte_vxlan_gpe_hdr *vxlan_gpe_hdr = NULL;
	uint16_t hdr_len;

	if (mbuf == NULL)
		return 0;
	if (mbuf->udata64 == 0)
		return 0;

	/* use header length saved in reserved 16bits of rte_mbuf to
	   "encapsulate" transport + NSH header by moving packet pointer */
	mbuf->data_len = (uint16_t)(mbuf->data_len + mbuf->udata64);
	mbuf->data_off -= mbuf->udata64;
	mbuf->pkt_len  = (uint32_t)(mbuf->pkt_len + mbuf->udata64);

	eth_hdr = rte_pktmbuf_mtod(mbuf, prox_rte_ether_hdr *);
	if (eth_hdr->ether_type == ETHER_NSH_TYPE) {
		nsh_hdr = (struct nsh_hdr *) (((unsigned char *)eth_hdr) + sizeof(prox_rte_ether_hdr));

		/* decrement Service Index in NSH header */
		if (nsh_hdr->sf_index > 0)
			nsh_hdr->sf_index -= 1;
	}
	else {
		/* "encapsulate" VxLAN-GPE + NSH header by moving packet pointer */
		if (mbuf->data_len < VXLAN_GPE_HDR_SZ)
			return 0;

		/* check the UDP destination port */
		udp_hdr = (prox_rte_udp_hdr *)(((unsigned char *)eth_hdr) + sizeof(prox_rte_ether_hdr) + sizeof(prox_rte_ipv4_hdr));
		if (udp_hdr->dst_port != VXLAN_GPE_NSH_TYPE)
			return 0;

		/* check the Next Protocol field in VxLAN-GPE header */
		vxlan_gpe_hdr = (prox_rte_vxlan_gpe_hdr *)(((unsigned char *)eth_hdr) + sizeof(prox_rte_ether_hdr) + sizeof(prox_rte_ipv4_hdr) + sizeof(prox_rte_udp_hdr));
		if (vxlan_gpe_hdr->proto != VXLAN_GPE_NP)
			return 0;

		/* decrement Service Index in NSH header */
		nsh_hdr = (struct nsh_hdr *)(((unsigned char *)vxlan_gpe_hdr) + sizeof(prox_rte_vxlan_gpe_hdr));
		if (nsh_hdr->sf_index > 0)
			nsh_hdr->sf_index -= 1;
	}

	return 0;
}

static int handle_encap_nsh_bulk(struct task_base *tbase, struct rte_mbuf **mbufs, uint16_t n_pkts)
{
	struct task_encap_nsh *task = (struct task_encap_nsh *)tbase;
	uint8_t out[MAX_PKT_BURST];
	uint16_t j;

	prefetch_first(mbufs, n_pkts);
	for (j = 0; j + PREFETCH_OFFSET < n_pkts; ++j) {
#ifdef PROX_PREFETCH_OFFSET
		PREFETCH0(mbufs[j + PREFETCH_OFFSET]);
		PREFETCH0(rte_pktmbuf_mtod(mbufs[j + PREFETCH_OFFSET - 1], void *));
#endif
		out[j] = handle_encap_nsh(task, mbufs[j]);
	}
#ifdef PROX_PREFETCH_OFFSET
	PREFETCH0(rte_pktmbuf_mtod(mbufs[n_pkts - 1], void *));
	for (; j < n_pkts; ++j) {
		out[j] = handle_encap_nsh(task, mbufs[j]);
	}
#endif
	return task->base.tx_pkt(&task->base, mbufs, n_pkts, out);
}

static struct task_init task_init_decap_nsh = {
	.mode_str = "decapnsh",
	.init = init_task_decap_nsh,
	.handle = handle_decap_nsh_bulk,
	.thread_x = thread_generic,
	.size = sizeof(struct task_decap_nsh)
};

static struct task_init task_init_encap_nsh = {
	.mode_str = "encapnsh",
	.init = init_task_encap_nsh,
	.handle = handle_encap_nsh_bulk,
	.size = sizeof(struct task_encap_nsh)
};

__attribute__((constructor)) static void reg_task_nshtag(void)
{
	reg_task(&task_init_decap_nsh);
	reg_task(&task_init_encap_nsh);
}