/*      $OpenBSD: pppoe.h,v 1.8 2021/03/29 03:54:39 yasuoka Exp $ */

/*-
 * Copyright (c) 2009 Internet Initiative Japan Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#ifndef PPPOE_H
#define PPPOE_H 1

/*
 * Constant variables and types from PPPoE protocol (RFC 2516)
 */
#define PPPOE_RFC2516_TYPE      0x01
#define PPPOE_RFC2516_VER       0x01

/** The PPPoE Active Discovery Initiation (PADI) packet */
#define PPPOE_CODE_PADI         0x09

/** The PPPoE Active Discovery Offer (PADO) packet */
#define PPPOE_CODE_PADO         0x07

/** The PPPoE Active Discovery Request (PADR) packet */
#define PPPOE_CODE_PADR         0x19

/** The PPPoE Active Discovery Session-confirmation (PADS) packet */
#define PPPOE_CODE_PADS         0x65

/** The PPPoE Active Discovery Terminate (PADT) packet */
#define PPPOE_CODE_PADT         0xa7

#define PPPOE_TAG_END_OF_LIST           0x0000
#define PPPOE_TAG_SERVICE_NAME          0x0101
#define PPPOE_TAG_AC_NAME               0x0102
#define PPPOE_TAG_HOST_UNIQ             0x0103
#define PPPOE_TAG_AC_COOKIE             0x0104
#define PPPOE_TAG_VENDOR_SPECIFIC       0x0105
#define PPPOE_TAG_RELAY_SESSION_ID      0x0110
#define PPPOE_TAG_SERVICE_NAME_ERROR    0x0201
#define PPPOE_TAG_AC_SYSTEM_ERROR       0x0202
#define PPPOE_TAG_GENERIC_ERROR         0x0203

/** PPPoE Protocol Header */
struct pppoe_header {
#if BYTE_ORDER == BIG_ENDIAN
    uint8_t ver:4, type:4;
#else
    uint8_t type:4, ver:4;
#endif
    uint8_t code;
    uint16_t session_id;
    uint16_t length;
} __attribute__((__packed__));

/** PPPoE TLV Header */
struct pppoe_tlv {
        uint16_t        type;
        uint16_t        length;
        uint8_t         value[0];
} __attribute__((__packed__));

/*
 * Constant variables and types for implementions
 */
#include "pppoe_conf.h"

/** Default data link layer  */
#define PPPOED_DEFAULT_LAYER2_LABEL     "PPPoE"

#define PPPOED_CONFIG_BUFSIZ            65535
#define PPPOED_HOSTUNIQ_LEN             64
#define PPPOED_PHY_LABEL_SIZE           16

/*
 * pppoed status
 */
#define PPPOED_STATE_INIT               0 /** Initial */
#define PPPOED_STATE_RUNNING            1 /** Running */
#define PPPOED_STATE_STOPPED            2 /** Stopped */

#define pppoed_is_stopped(pppoed)       \
        (((pppoed)->state == PPPOED_STATE_STOPPED)? 1 : 0)
#define pppoed_is_running(pppoed)       \
        (((pppoed)->state == PPPOED_STATE_RUNNING)? 1 : 0)

#define PPPOED_LISTENER_INVALID_INDEX   UINT16_MAX

/** PPPoE listener type */
typedef struct _pppoed_listener {
        /** Descriptor of bpf(4) */
        int bpf;
        /** Context of event(3) for the descriptor of bpf(4) */
        struct event ev_bpf;
        /** Pointer to base PPPoE daemon */
        struct _pppoed *self;
        /** Ethernet address */
        u_char  ether_addr[ETHER_ADDR_LEN];
        /** Listener index numbered  by the base PPPoE daemon */
        uint16_t        index;
        /** Listening interface name */
        char    listen_ifname[IF_NAMESIZE];
        /** Label of physcal layer */
        char    tun_name[PPPOED_PHY_LABEL_SIZE];
        /** Configuration */
        struct pppoe_conf *conf;
} pppoed_listener;

/** PPPoE daemon type */
typedef struct _pppoed {
        /** PPPoE daemon Id */
        int id;
        /** List of {@link pppoed_listener} */
        slist listener;
        /** Status of this daemon */
        int state;

        /** Hashmap that maps from session number to {@link pppoe_session} */
        hash_table      *session_hash;
        /** List of free session numbers */
        slist   session_free_list;

        /** Hashmap that contains uniq cookie value */
        hash_table      *acookie_hash;
        /** Next cookie number */
        uint32_t        acookie_next;

        /** Flags */
        uint32_t
            listen_incomplete:1,
            reserved:31;
} pppoed;

/** PPPoE session type */
typedef struct _pppoe_session {
        /** State of this session */
        int             state;
        /** Pointer to base {@link pppoed *} PPPoE daemon */
        pppoed          *pppoed;
        /** Pointer to the PPP context */
        void            *ppp;
        /** Session id */
        uint16_t        session_id;
        /** Cookie number */
        int             acookie;
        /** Peer ethernet address */
        u_char          ether_addr[ETHER_ADDR_LEN];
        /** Index of listener */
        uint16_t        listener_index;
        /** Cache for ethernet frame header */
        struct ether_header ehdr;
        int lcp_echo_interval;                  /* XXX can remove */
        int lcp_echo_max_failure;               /* XXX can remove */
        /** Context of event(3) for disposing */
        struct event ev_disposing;
} pppoe_session;

#define PPPOE_SESSION_STATE_INIT                0 /** Initial */
#define PPPOE_SESSION_STATE_RUNNING             1 /** Running */
#define PPPOE_SESSION_STATE_DISPOSING           2 /** Disposing */

#define pppoed_need_polling(pppoed)     \
    (((pppoed)->listen_incomplete != 0)? 1 : 0)

#ifdef __cplusplus
extern "C" {
#endif

int         pppoe_session_init (pppoe_session *, pppoed *, int, int, u_char *);
void        pppoe_session_fini (pppoe_session *);
void        pppoe_session_stop (pppoe_session *);
int         pppoe_session_recv_PADR (pppoe_session *, slist *);
int         pppoe_session_recv_PADT (pppoe_session *, slist *);
void        pppoe_session_input (pppoe_session *, u_char *, int);
void        pppoe_session_disconnect (pppoe_session *);

int         pppoed_add_listener (pppoed *, int, const char *, const char *);
int         pppoed_reload_listeners(pppoed *);

int         pppoed_init (pppoed *);
int         pppoed_start (pppoed *);
void        pppoed_stop (pppoed *);
void        pppoed_uninit (pppoed *);
void        pppoed_pppoe_session_close_notify(pppoed *, pppoe_session *);
const char *pppoed_tlv_value_string(struct pppoe_tlv *);
int         pppoed_reload(pppoed *, struct pppoe_confs *);

#ifdef __cplusplus
}
#endif
#endif