// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OSPF Sending and Receiving OSPF Packets.
 * Copyright (C) 1999 Toshiaki Takada
 */

#ifndef _ZEBRA_OSPF_PACKET_H
#define _ZEBRA_OSPF_PACKET_H

#define OSPF_HEADER_SIZE         24U
#define OSPF_AUTH_SIMPLE_SIZE     8U
#define OSPF_AUTH_MD5_SIZE       16U

#define OSPF_MAX_PACKET_SIZE  65535U   /* includes IP Header size. */
#define OSPF_HELLO_MIN_SIZE      20U   /* not including neighbors */
#define OSPF_DB_DESC_MIN_SIZE     8U
#define OSPF_LS_REQ_MIN_SIZE      0U
#define OSPF_LS_UPD_MIN_SIZE      4U
#define OSPF_LS_ACK_MIN_SIZE      0U

#define OSPF_MSG_HELLO 1   /* OSPF Hello Message. */
#define OSPF_MSG_DB_DESC 2 /* OSPF Database Description Message. */
#define OSPF_MSG_LS_REQ 3  /* OSPF Link State Request Message. */
#define OSPF_MSG_LS_UPD 4  /* OSPF Link State Update Message. */
#define OSPF_MSG_LS_ACK 5  /* OSPF Link State Acknowledgement Message. */

#define OSPF_SEND_PACKET_DIRECT         1
#define OSPF_SEND_PACKET_INDIRECT       2
#define OSPF_SEND_PACKET_LOOP           3

#define OSPF_HELLO_REPLY_DELAY          1

/* Return values of functions involved in packet verification, see ospf6d. */
#define MSG_OK    0
#define MSG_NG    1

struct ospf_packet {
	struct ospf_packet *next;

	/* Pointer to data stream. */
	struct stream *s;

	/* IP destination address. */
	struct in_addr dst;

	/* OSPF packet length. */
	uint16_t length;
};

/* OSPF packet queue structure. */
struct ospf_fifo {
	unsigned long count;

	struct ospf_packet *head;
	struct ospf_packet *tail;
};

/* OSPF packet header structure. */
struct ospf_header {
	uint8_t version;	  /* OSPF Version. */
	uint8_t type;		  /* Packet Type. */
	uint16_t length;	  /* Packet Length. */
	struct in_addr router_id; /* Router ID. */
	struct in_addr area_id;   /* Area ID. */
	uint16_t checksum;	/* Check Sum. */
	uint16_t auth_type;       /* Authentication Type. */
	/* Authentication Data. */
	union {
		/* Simple Authentication. */
		uint8_t auth_data[OSPF_AUTH_SIMPLE_SIZE];
		/* Cryptographic Authentication. */
		struct {
			uint16_t zero;	 /* Should be 0. */
			uint8_t key_id;	/* Key ID. */
			uint8_t auth_data_len; /* Auth Data Length. */
			uint32_t crypt_seqnum; /* Cryptographic Sequence
						   Number. */
		} crypt;
	} u;
};

/* OSPF Hello body format. */
struct ospf_hello {
	struct in_addr network_mask;
	uint16_t hello_interval;
	uint8_t options;
	uint8_t priority;
	uint32_t dead_interval;
	struct in_addr d_router;
	struct in_addr bd_router;
	struct in_addr neighbors[1];
};

/* OSPF Database Description body format. */
struct ospf_db_desc {
	uint16_t mtu;
	uint8_t options;
	uint8_t flags;
	uint32_t dd_seqnum;
};

struct ospf_ls_update {
	uint32_t num_lsas;
};

/* Macros. */
/* XXX Perhaps obsolete; function in ospf_packet.c */
#define OSPF_PACKET_MAX(oi)     ospf_packet_max (oi)

#define OSPF_OUTPUT_PNT(S)      ((S)->data + (S)->putp)
#define OSPF_OUTPUT_LENGTH(S)   ((S)->endp)

#define IS_SET_DD_MS(X)         ((X) & OSPF_DD_FLAG_MS)
#define IS_SET_DD_M(X)          ((X) & OSPF_DD_FLAG_M)
#define IS_SET_DD_I(X)          ((X) & OSPF_DD_FLAG_I)
#define IS_SET_DD_ALL(X)        ((X) & OSPF_DD_FLAG_ALL)

/* Prototypes. */
extern void ospf_packet_free(struct ospf_packet *);
extern struct ospf_fifo *ospf_fifo_new(void);
extern void ospf_fifo_push(struct ospf_fifo *, struct ospf_packet *);
extern struct ospf_packet *ospf_fifo_pop(struct ospf_fifo *);
extern struct ospf_packet *ospf_fifo_head(struct ospf_fifo *);
extern void ospf_fifo_flush(struct ospf_fifo *);
extern void ospf_fifo_free(struct ospf_fifo *);

extern void ospf_read(struct event *thread);
extern void ospf_hello_send(struct ospf_interface *);
extern void ospf_db_desc_send(struct ospf_neighbor *);
extern void ospf_db_desc_resend(struct ospf_neighbor *);
extern void ospf_ls_req_send(struct ospf_neighbor *);
extern void ospf_ls_upd_send_lsa(struct ospf_neighbor *, struct ospf_lsa *,
				 int);
extern void ospf_ls_upd_send(struct ospf_neighbor *, struct list *, int, int);
extern void ospf_ls_upd_queue_send(struct ospf_interface *oi,
				   struct list *update, struct in_addr addr,
				   int send_lsupd_now);
extern void ospf_ls_ack_send(struct ospf_neighbor *, struct ospf_lsa *);
extern void ospf_ls_ack_send_delayed(struct ospf_interface *);
extern void ospf_ls_retransmit(struct ospf_interface *, struct ospf_lsa *);
extern void ospf_ls_req_event(struct ospf_neighbor *);

extern void ospf_ls_upd_timer(struct event *thread);
extern void ospf_ls_ack_timer(struct event *thread);
extern void ospf_poll_timer(struct event *thread);
extern void ospf_hello_reply_timer(struct event *thread);

extern const struct message ospf_packet_type_str[];
extern const size_t ospf_packet_type_str_max;

extern void ospf_proactively_arp(struct ospf_neighbor *);

#endif /* _ZEBRA_OSPF_PACKET_H */