/* Global definitions for osmo-upf-load-gen */
/*
 * (C) 2021-2022 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
 * All Rights Reserved.
 *
 * Author: Neels Janosch Hofmeyr <nhofmeyr@sysmocom.de>
 *
 * SPDX-License-Identifier: GPL-2.0+
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#pragma once

#include <osmocom/core/linuxlist.h>
#include <osmocom/core/tdef.h>
#include <osmocom/core/socket.h>
#include <osmocom/core/sockaddr_str.h>
#include <osmocom/core/select.h>
#include <osmocom/vty/command.h>

#include <osmocom/pfcp/pfcp_msg.h>

#include <osmocom/upfloadgen/range.h>
#include <osmocom/upfloadgen/gtp_flood.h>

struct osmo_tdef;
struct ctrl_handle;

enum up_gtp_action_kind {
	UP_GTP_DROP,
	UP_GTP_U_TUNEND,
	UP_GTP_U_TUNMAP,
};

enum pfcp_tool_vty_node {
	PEER_NODE = _LAST_OSMOVTY_NODE + 1,
	SESSION_NODE,
	GTP_FLOOD_NODE,
};

extern struct osmo_tdef g_pfcp_tool_tdefs[];
extern struct osmo_tdef_group g_pfcp_tool_tdef_groups[];

struct pfcp_tool_peer {
	struct llist_head entry;

	struct osmo_sockaddr remote_addr;
	struct osmo_pfcp_msg last_req;
	struct osmo_pfcp_msg last_resp;

	uint64_t next_seid_state;

	struct llist_head sessions;
};

struct pfcp_tool_gtp_tun_ep {
	struct osmo_sockaddr_str addr;
	uint32_t teid;
};

struct pfcp_tool_gtp_tun {
	struct pfcp_tool_gtp_tun_ep local;
	struct pfcp_tool_gtp_tun_ep remote;
};

struct pfcp_tool_tunend {
	struct pfcp_tool_gtp_tun access;
	struct {
		struct osmo_sockaddr_str ue_local_addr;
	} core;
};

struct pfcp_tool_tunmap {
	struct pfcp_tool_gtp_tun access;
	struct pfcp_tool_gtp_tun core;
};

struct pfcp_tool_session {
	struct llist_head entry;

	struct pfcp_tool_peer *peer;
	uint64_t cp_seid;
	struct osmo_pfcp_ie_f_seid up_f_seid;

	enum up_gtp_action_kind kind;
	union {
		/* En-/De-capsulate GTP: add/remove a GTP header and forward the GTP payload from/to plain IP. */
		struct pfcp_tool_tunend tunend;

		/* Tunnel-map GTP: translate from one TEID to another and forward */
		struct pfcp_tool_tunmap tunmap;
	};
};

struct udp_port {
	struct llist_head entry;

	/* IP address and UDP port from user input */
	struct osmo_sockaddr osa;

	/* In case this is a locally bound port, this is the fd for the socket. */
	struct osmo_fd ofd;
};

struct g_pfcp_tool {
	struct ctrl_handle *ctrl;

	struct {
		char *local_ip;
		uint16_t local_port;
	} vty_cfg;

	struct osmo_pfcp_endpoint *ep;
	struct llist_head peers;

	uint32_t next_teid_state;

	struct {
		struct range ip_range;
	} ue;

	struct {
		/* list of struct udp_port */
		struct llist_head gtp_local_addrs;
		struct udp_port *gtp_local_addrs_next;

		/* list of struct udp_port */
		struct llist_head gtp_core_addrs;
		void *gtp_core_addrs_next;

		struct {
			struct {
				/* source address is always the UE IP address */
				struct range udp_port_range;
			} source;
			struct {
				struct range ip_range;
				struct range udp_port_range;
			} target;
			bool append_info;
		} payload;

		struct {
			struct gtp_flood_cfg cfg;

			unsigned int flows_per_session;
			unsigned int packets_per_flow;

			struct gtp_flood *state;
		} flood;
	} gtp;
};

extern struct g_pfcp_tool *g_pfcp_tool;

void g_pfcp_tool_alloc(void *ctx);
void pfcp_tool_vty_init_cfg();
void pfcp_tool_vty_init_cmds();

int pfcp_tool_mainloop(int poll);

struct pfcp_tool_peer *pfcp_tool_peer_find_or_create(const struct osmo_sockaddr *remote_addr);
struct pfcp_tool_session *pfcp_tool_session_find_or_create(struct pfcp_tool_peer *peer, uint64_t cp_seid,
							   enum up_gtp_action_kind kind);
void pfcp_tool_rx_msg(struct osmo_pfcp_endpoint *ep, struct osmo_pfcp_msg *m, struct osmo_pfcp_msg *req);

int peer_tx(struct pfcp_tool_peer *peer, struct osmo_pfcp_msg *m);
uint64_t peer_new_seid(struct pfcp_tool_peer *peer);

uint32_t pfcp_tool_new_teid(void);
int pfcp_tool_next_ue_addr(struct osmo_sockaddr *dst);

struct udp_port *pfcp_tool_have_local_udp_port_by_str(const struct osmo_sockaddr_str *addr, uint16_t fallback_port);
struct udp_port *pfcp_tool_have_core_udp_port_by_str(const struct osmo_sockaddr_str *addr, uint16_t fallback_port);

void pfcp_tool_gtp_flood_start(void);

int pfcp_tool_vty_go_parent(struct vty *vty);

static inline struct llist_head *_llist_round_robin(struct llist_head *list, void **state)
{
	struct llist_head *e = *state;
	if (!e || e->next == list)
		e = list;
	e = e->next;
	if (e == list)
		e = NULL;
	*state = e;
	return e;
}
#define llist_round_robin(LIST, STATE, STRUCT, ENTRY_NAME) \
	llist_entry(_llist_round_robin(LIST, STATE), STRUCT, ENTRY_NAME)