// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * IS-IS Rout(e)ing protocol - isis_pdu.h
 *                             PDU processing
 *
 * Copyright (C) 2001,2002   Sampo Saaristo
 *                           Tampere University of Technology
 *                           Institute of Communications Engineering
 */

#ifndef _ZEBRA_ISIS_PDU_H
#define _ZEBRA_ISIS_PDU_H

#include "isisd/isis_tx_queue.h"

#ifdef __SUNPRO_C
#pragma pack(1)
#endif

/*
 *                    ISO 9542 - 7.5,7.6
 *
 *                       ES to IS Fixed Header
 *  +-------+-------+-------+-------+-------+-------+-------+-------+
 *  |         Intradomain Routeing Protocol Discriminator           |
 *  +-------+-------+-------+-------+-------+-------+-------+-------+
 *  |                       Length Indicator                        |
 *  +-------+-------+-------+-------+-------+-------+-------+-------+
 *  |                  Version/Protocol ID extension                |
 *  +-------+-------+-------+-------+-------+-------+-------+-------+
 *  |                         Reserved = 0                          |
 *  +-------+-------+-------+-------+-------+-------+-------+-------+
 *  |   0   |   0   |   0   |              PDU Type                 |
 *  +-------+-------+-------+-------+-------+-------+-------+-------+
 *  |                         Holding Time                          | 2
 *  +-------+-------+-------+-------+-------+-------+-------+-------+
 *  |                          Checksum                             | 2
 *  +-------+-------+-------+-------+-------+-------+-------+-------+
 */

struct esis_fixed_hdr {
	uint8_t idrp;
	uint8_t length;
	uint8_t version;
	uint8_t id_len;
	uint8_t pdu_type;
	uint16_t holdtime;
	uint16_t checksum;
} __attribute__((packed));

#define ESIS_FIXED_HDR_LEN   9

#define ESH_PDU              2
#define ISH_PDU              4
#define RD_PDU               5

#define ISIS_FIXED_HDR_LEN 8

/*
 * IS-IS PDU types.
 */

#define L1_LAN_HELLO         15
#define L2_LAN_HELLO         16
/*
 *              L1 and L2 LAN IS to IS Hello PDU header
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * |                       Reserved                | Circuit Type  | 1
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * +                        Source ID                              + id_len
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * |                        Holding  Time                          | 2
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * |                        PDU Length                             | 2
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * |   R   |                Priority                               | 1
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * |                        LAN ID                                 | id_len + 1
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 */
struct isis_lan_hello_hdr {
	uint8_t circuit_t;
	uint8_t source_id[ISIS_SYS_ID_LEN];
	uint16_t hold_time;
	uint16_t pdu_len;
	uint8_t prio;
	uint8_t lan_id[ISIS_SYS_ID_LEN + 1];
} __attribute__((packed));
#define ISIS_LANHELLO_HDRLEN  19

#define P2P_HELLO            17
/*
 *           Point-to-point IS to IS hello PDU header
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * |                        Reserved               | Circuit Type  | 1
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * +                        Source ID                              + id_len
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * +                        Holding  Time                          + 2
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * +                        PDU Length                             + 2
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * |                        Local Circuit ID                       | 1
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 */
struct isis_p2p_hello_hdr {
	uint8_t circuit_t;
	uint8_t source_id[ISIS_SYS_ID_LEN];
	uint16_t hold_time;
	uint16_t pdu_len;
	uint8_t local_id;
} __attribute__((packed));
#define ISIS_P2PHELLO_HDRLEN 12

#define L1_LINK_STATE        18
#define L2_LINK_STATE        20
#define FS_LINK_STATE        10
#define L2_CIRCUIT_FLOODING_SCOPE 2
struct isis_lsp_hdr {
	uint16_t pdu_len;
	uint16_t rem_lifetime;
	uint8_t lsp_id[ISIS_SYS_ID_LEN + 2];
	uint32_t seqno;
	uint16_t checksum;
	uint8_t lsp_bits;
};
#define ISIS_LSP_HDR_LEN 19

/*
 * Since the length field of LSP Entries TLV is one byte long, and each LSP
 * entry is LSP_ENTRIES_LEN (16) bytes long, the maximum number of LSP entries
 * can be accommodated in a TLV is
 * 255 / 16 = 15.
 *
 * Therefore, the maximum length of the LSP Entries TLV is
 * 16 * 15 + 2 (header) = 242 bytes.
 */
#define MAX_LSP_ENTRIES_TLV_SIZE 242

#define L1_COMPLETE_SEQ_NUM  24
#define L2_COMPLETE_SEQ_NUM  25
/*
 *      L1 and L2 IS to IS complete sequence numbers PDU header
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * +                        PDU Length                             + 2
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * +                        Source ID                              + id_len + 1
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * +                        Start LSP ID                           + id_len + 2
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * +                        End LSP ID                             + id_len + 2
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 */
struct isis_complete_seqnum_hdr {
	uint16_t pdu_len;
	uint8_t source_id[ISIS_SYS_ID_LEN + 1];
	uint8_t start_lsp_id[ISIS_SYS_ID_LEN + 2];
	uint8_t stop_lsp_id[ISIS_SYS_ID_LEN + 2];
};
#define ISIS_CSNP_HDRLEN 25

#define L1_PARTIAL_SEQ_NUM   26
#define L2_PARTIAL_SEQ_NUM   27
/*
 *      L1 and L2 IS to IS partial sequence numbers PDU header
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * +                        PDU Length                             + 2
 * +-------+-------+-------+-------+-------+-------+-------+-------+
 * +                        Source ID                              + id_len + 1
 * +---------------------------------------------------------------+
 */
struct isis_partial_seqnum_hdr {
	uint16_t pdu_len;
	uint8_t source_id[ISIS_SYS_ID_LEN + 1];
};
#define ISIS_PSNP_HDRLEN 9

#ifdef __SUNPRO_C
#pragma pack()
#endif

/*
 * Function for receiving IS-IS PDUs
 */
void isis_receive(struct event *thread);

/*
 * calling arguments for snp_process ()
 */
#define ISIS_SNP_PSNP_FLAG 0
#define ISIS_SNP_CSNP_FLAG 1

#define ISIS_AUTH_MD5_SIZE       16U

/*
 * Sending functions
 */
void send_hello_sched(struct isis_circuit *circuit, int level, long delay);
int send_csnp(struct isis_circuit *circuit, int level);
void send_l1_csnp(struct event *thread);
void send_l2_csnp(struct event *thread);
void send_l1_psnp(struct event *thread);
void send_l2_psnp(struct event *thread);
void send_lsp(struct isis_circuit *circuit,
	      struct isis_lsp *lsp, enum isis_tx_type tx_type);
void fill_fixed_hdr(uint8_t pdu_type, struct stream *stream);
int send_hello(struct isis_circuit *circuit, int level);
int isis_handle_pdu(struct isis_circuit *circuit, uint8_t *ssnpa);
void isis_log_pdu_drops(struct isis_area *area, const char *pdu_type);

#endif /* _ZEBRA_ISIS_PDU_H */