/*
// 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 "genl4_stream_udp.h"
#include "mbuf_utils.h"

int stream_udp_is_ended(struct stream_ctx *ctx)
{
	return ctx->cur_action == ctx->stream_cfg->n_actions;
}

static void update_token_times(struct stream_ctx *ctx)
{
	uint64_t now = rte_rdtsc();

	token_time_update(&ctx->token_time_other, now);
	token_time_update(&ctx->token_time, now);
}

int stream_udp_proc(struct stream_ctx *ctx, struct rte_mbuf *mbuf, struct l4_meta *l4_meta, uint64_t *next_tsc)
{
	update_token_times(ctx);

	if (l4_meta) {
		enum l4gen_peer peer = ctx->stream_cfg->actions[ctx->cur_action].peer;
		plogx_dbg("Consuming UDP data\n");
		/* data should come from the other side */
		if (peer == ctx->peer) {
			plogx_err("Wrong peer\n");
			return -1;
		}
		/* Fixed length data expected */
		if (ctx->stream_cfg->actions[ctx->cur_action].len != l4_meta->len) {
			plogx_dbg("unexpected UDP len (expected = %u, got = %u, action = %u)\n",
				  ctx->stream_cfg->actions[ctx->cur_action].len,
				  l4_meta->len,
				  ctx->cur_action);

			return -1;
		}
		/* With specific payload */
		if (memcmp(ctx->stream_cfg->data[peer].content + ctx->stream_cfg->actions[ctx->cur_action].beg, l4_meta->payload, l4_meta->len) != 0) {
			plogx_dbg("Bad payload at action_id %d, with peer = %d and pos = %d and len=%d\n", ctx->cur_action, peer, ctx->cur_pos[peer], l4_meta->len);
			return -1;
		}
		ctx->cur_pos[peer] += l4_meta->len;
		ctx->cur_action++;

		if (stream_udp_is_ended(ctx))
			return -1;

		token_time_take(&ctx->token_time_other, mbuf_wire_size(mbuf));
		/* Time before next packet is expected to
		   arrive. Note, addition amount of time is accounted
		   for due to rate limiting. */
		uint64_t wait = token_time_tsc_until_full(&ctx->token_time_other);
		*next_tsc = wait + ctx->stream_cfg->tsc_timeout;
	}

	if (ctx->stream_cfg->actions[ctx->cur_action].peer != ctx->peer) {
		const char *other_peer_str = ctx->peer != PEER_SERVER? "server" : "client";

		plogx_dbg("Expecting more UDP data from %s, will expire = %s\n", other_peer_str, l4_meta == NULL? "yes" : "no");
		if (!l4_meta) {
			ctx->flags |= STREAM_CTX_F_EXPIRED;
		}
		return -1;
	}

	uint64_t wait_tsc = token_time_tsc_until_full(&ctx->token_time);

	if (wait_tsc != 0) {
		plogx_dbg("Wait = %"PRIu64"\n", wait_tsc);
		*next_tsc = wait_tsc;
		return -1;
	}

	const struct stream_cfg *stream_cfg = ctx->stream_cfg;

	uint8_t *pkt = rte_pktmbuf_mtod(mbuf, uint8_t *);
	const struct peer_action *act = &stream_cfg->actions[ctx->cur_action];

	uint16_t pkt_len = stream_cfg->data[act->peer].hdr_len + sizeof(struct udp_hdr) + act->len;

	rte_pktmbuf_pkt_len(mbuf) = pkt_len;
	rte_pktmbuf_data_len(mbuf) = pkt_len;
	plogx_dbg("Creating UDP data (peer = %s, payload len = %u)\n", act->peer == PEER_CLIENT? "client" : "server", act->len);
	/* Construct the packet. The template is used up to L4 header,
	   a gap of sizeof(l4_hdr) is skipped, followed by the payload. */
	rte_memcpy(pkt, stream_cfg->data[act->peer].hdr, stream_cfg->data[act->peer].hdr_len);
	rte_memcpy(pkt + stream_cfg->data[act->peer].hdr_len + sizeof(struct udp_hdr), stream_cfg->data[act->peer].content + act->beg, act->len);

	struct ipv4_hdr *l3_hdr = (struct ipv4_hdr*)&pkt[stream_cfg->data[act->peer].hdr_len - sizeof(struct ipv4_hdr)];
	struct udp_hdr *l4_hdr = (struct udp_hdr*)&pkt[stream_cfg->data[act->peer].hdr_len];

	l3_hdr->src_addr = ctx->tuple->dst_addr;
	l3_hdr->dst_addr = ctx->tuple->src_addr;
	l3_hdr->next_proto_id = IPPROTO_UDP;
	l4_hdr->src_port = ctx->tuple->dst_port;
	l4_hdr->dst_port = ctx->tuple->src_port;
	l4_hdr->dgram_len = rte_bswap16(sizeof(struct udp_hdr) + act->len);
	/* TODO: UDP checksum calculation */
	l3_hdr->total_length = rte_bswap16(sizeof(struct ipv4_hdr) + sizeof(struct udp_hdr) + act->len);
	ctx->cur_pos[ctx->peer] += act->len;
	ctx->cur_action++;

	/* When the stream has ended, there is no need to schedule
	   another timeout (which will be unscheduled at the end of
	   the stream). */
	if (stream_udp_is_ended(ctx))
		return 0;

	token_time_take(&ctx->token_time, mbuf_wire_size(mbuf));

	/* Send next packet as soon as possible */
	if (ctx->stream_cfg->actions[ctx->cur_action].peer == ctx->peer) {
		*next_tsc = token_time_tsc_until_full(&ctx->token_time);
	}
	else {
		uint64_t wait = token_time_tsc_until_full(&ctx->token_time_other);
		*next_tsc = wait + ctx->stream_cfg->tsc_timeout;
	}

	return 0;
}

uint16_t stream_udp_reply_len(struct stream_ctx *ctx)
{
	if (stream_udp_is_ended(ctx))
		return 0;
	else if (ctx->stream_cfg->actions[ctx->cur_action].peer == ctx->peer)
		return 0;
	else
		return ctx->stream_cfg->data[ctx->stream_cfg->actions[ctx->cur_action].peer].hdr_len + sizeof(struct udp_hdr) +
			ctx->stream_cfg->actions[ctx->cur_action].len;
}

void stream_udp_calc_len(struct stream_cfg *cfg, uint32_t *n_pkts, uint32_t *n_bytes)
{
	const uint32_t client_hdr_len = cfg->data[PEER_CLIENT].hdr_len;
	const uint32_t server_hdr_len = cfg->data[PEER_SERVER].hdr_len;

	*n_pkts = 0;
	*n_bytes = 0;

	for (uint32_t i = 0; i < cfg->n_actions; ++i) {
		const uint32_t send_hdr_len = cfg->actions[i].peer == PEER_CLIENT? client_hdr_len : server_hdr_len;
		uint32_t len = send_hdr_len + sizeof(struct udp_hdr) + cfg->actions[i].len;
		*n_bytes += (len < 60? 60 : len) + 24;
		(*n_pkts)++;
	}
}