src/include/netif/ppp/ppp.h

/*****************************************************************************
* ppp.h - Network Point to Point Protocol header file.
*
* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
* portions Copyright (c) 1997 Global Election Systems Inc.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice and the following disclaimer are included verbatim in any 
* distributions. No written agreement, license, or royalty fee is required
* for any of the authorized uses.
*
* THIS SOFTWARE IS PROVIDED BY THE 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 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.
*
******************************************************************************
* REVISION HISTORY
*
* 03-01-01 Marc Boucher <marc@mbsi.ca>
*   Ported to lwIP.
* 97-11-05 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc.
*   Original derived from BSD codes.
*****************************************************************************/

#include "netif/ppp/ppp_opts.h"
#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */

#ifndef PPP_H
#define PPP_H

#include "lwip/def.h"
#include "lwip/stats.h"
#include "lwip/mem.h"
#include "lwip/netif.h"
#include "lwip/sys.h"
#include "lwip/timeouts.h"
#if PPP_IPV6_SUPPORT
#include "lwip/ip6_addr.h"
#endif /* PPP_IPV6_SUPPORT */

#ifdef __cplusplus
extern "C" {
#endif

/* Disable non-working or rarely used PPP feature, so rarely that we don't want to bloat ppp_opts.h with them */
#ifndef PPP_OPTIONS
#define PPP_OPTIONS         0
#endif

#ifndef PPP_NOTIFY
#define PPP_NOTIFY          0
#endif

#ifndef PPP_REMOTENAME
#define PPP_REMOTENAME      0
#endif

#ifndef PPP_IDLETIMELIMIT
#define PPP_IDLETIMELIMIT   0
#endif

#ifndef PPP_LCP_ADAPTIVE
#define PPP_LCP_ADAPTIVE    0
#endif

#ifndef PPP_MAXCONNECT
#define PPP_MAXCONNECT      0
#endif

#ifndef PPP_ALLOWED_ADDRS
#define PPP_ALLOWED_ADDRS   0
#endif

#ifndef PPP_PROTOCOLNAME
#define PPP_PROTOCOLNAME    0
#endif

#ifndef PPP_STATS_SUPPORT
#define PPP_STATS_SUPPORT   0
#endif

#ifndef DEFLATE_SUPPORT
#define DEFLATE_SUPPORT     0
#endif

#ifndef BSDCOMPRESS_SUPPORT
#define BSDCOMPRESS_SUPPORT 0
#endif

#ifndef PREDICTOR_SUPPORT
#define PREDICTOR_SUPPORT   0
#endif

/*************************
*** PUBLIC DEFINITIONS ***
*************************/

/*
 * The basic PPP frame.
 */
#define PPP_HDRLEN	4	/* octets for standard ppp header */
#define PPP_FCSLEN	2	/* octets for FCS */

/*
 * Values for phase.
 */
#define PPP_PHASE_DEAD          0
#define PPP_PHASE_MASTER        1
#define PPP_PHASE_HOLDOFF       2
#define PPP_PHASE_INITIALIZE    3
#define PPP_PHASE_SERIALCONN    4
#define PPP_PHASE_DORMANT       5
#define PPP_PHASE_ESTABLISH     6
#define PPP_PHASE_AUTHENTICATE  7
#define PPP_PHASE_CALLBACK      8
#define PPP_PHASE_NETWORK       9
#define PPP_PHASE_RUNNING       10
#define PPP_PHASE_TERMINATE     11
#define PPP_PHASE_DISCONNECT    12

/* Error codes. */
#define PPPERR_NONE         0  /* No error. */
#define PPPERR_PARAM        1  /* Invalid parameter. */
#define PPPERR_OPEN         2  /* Unable to open PPP session. */
#define PPPERR_DEVICE       3  /* Invalid I/O device for PPP. */
#define PPPERR_ALLOC        4  /* Unable to allocate resources. */
#define PPPERR_USER         5  /* User interrupt. */
#define PPPERR_CONNECT      6  /* Connection lost. */
#define PPPERR_AUTHFAIL     7  /* Failed authentication challenge. */
#define PPPERR_PROTOCOL     8  /* Failed to meet protocol. */
#define PPPERR_PEERDEAD     9  /* Connection timeout */
#define PPPERR_IDLETIMEOUT  10 /* Idle Timeout */
#define PPPERR_CONNECTTIME  11 /* Max connect time reached */
#define PPPERR_LOOPBACK     12 /* Loopback detected */

/* Whether auth support is enabled at all */
#define PPP_AUTH_SUPPORT (PAP_SUPPORT || CHAP_SUPPORT || EAP_SUPPORT)

/************************
*** PUBLIC DATA TYPES ***
************************/

/*
 * Other headers require ppp_pcb definition for prototypes, but ppp_pcb
 * require some structure definition from other headers as well, we are
 * fixing the dependency loop here by declaring the ppp_pcb type then
 * by including headers containing necessary struct definition for ppp_pcb
 */
typedef struct ppp_pcb_s ppp_pcb;

/* Type definitions for BSD code. */
#ifndef __u_char_defined
typedef unsigned long  u_long;
typedef unsigned int   u_int;
typedef unsigned short u_short;
typedef unsigned char  u_char;
#endif

#include "fsm.h"
#include "lcp.h"
#if CCP_SUPPORT
#include "ccp.h"
#endif /* CCP_SUPPORT */
#if MPPE_SUPPORT
#include "mppe.h"
#endif /* MPPE_SUPPORT */
#if PPP_IPV4_SUPPORT
#include "ipcp.h"
#endif /* PPP_IPV4_SUPPORT */
#if PPP_IPV6_SUPPORT
#include "ipv6cp.h"
#endif /* PPP_IPV6_SUPPORT */
#if PAP_SUPPORT
#include "upap.h"
#endif /* PAP_SUPPORT */
#if CHAP_SUPPORT
#include "chap-new.h"
#endif /* CHAP_SUPPORT */
#if EAP_SUPPORT
#include "eap.h"
#endif /* EAP_SUPPORT */
#if VJ_SUPPORT
#include "vj.h"
#endif /* VJ_SUPPORT */

/* Link status callback function prototype */
typedef void (*ppp_link_status_cb_fn)(ppp_pcb *pcb, int err_code, void *ctx);

/*
 * PPP configuration.
 */
typedef struct ppp_settings_s {

#if PPP_SERVER && PPP_AUTH_SUPPORT
  unsigned int  auth_required       :1;      /* Peer is required to authenticate */
  unsigned int  null_login          :1;      /* Username of "" and a password of "" are acceptable */
#endif /* PPP_SERVER && PPP_AUTH_SUPPORT */
#if PPP_REMOTENAME
  unsigned int  explicit_remote     :1;      /* remote_name specified with remotename opt */
#endif /* PPP_REMOTENAME */
#if PAP_SUPPORT
  unsigned int  refuse_pap          :1;      /* Don't proceed auth. with PAP */
#endif /* PAP_SUPPORT */
#if CHAP_SUPPORT
  unsigned int  refuse_chap         :1;      /* Don't proceed auth. with CHAP */
#endif /* CHAP_SUPPORT */
#if MSCHAP_SUPPORT
  unsigned int  refuse_mschap       :1;      /* Don't proceed auth. with MS-CHAP */
  unsigned int  refuse_mschap_v2    :1;      /* Don't proceed auth. with MS-CHAPv2 */
#endif /* MSCHAP_SUPPORT */
#if EAP_SUPPORT
  unsigned int  refuse_eap          :1;      /* Don't proceed auth. with EAP */
#endif /* EAP_SUPPORT */
#if LWIP_DNS
  unsigned int  usepeerdns          :1;      /* Ask peer for DNS adds */
#endif /* LWIP_DNS */
  unsigned int  persist             :1;      /* Persist mode, always try to open the connection */
#if PRINTPKT_SUPPORT
  unsigned int  hide_password       :1;      /* Hide password in dumped packets */
#endif /* PRINTPKT_SUPPORT */
  unsigned int  noremoteip          :1;      /* Let him have no IP address */
  unsigned int  lax_recv            :1;      /* accept control chars in asyncmap */
  unsigned int  noendpoint          :1;      /* don't send/accept endpoint discriminator */
#if PPP_LCP_ADAPTIVE
  unsigned int lcp_echo_adaptive    :1;      /* request echo only if the link was idle */
#endif /* PPP_LCP_ADAPTIVE */
#if MPPE_SUPPORT
  unsigned int require_mppe         :1;      /* Require MPPE (Microsoft Point to Point Encryption) */
  unsigned int refuse_mppe_40       :1;      /* Allow MPPE 40-bit mode? */
  unsigned int refuse_mppe_128      :1;      /* Allow MPPE 128-bit mode? */
  unsigned int refuse_mppe_stateful :1;      /* Allow MPPE stateful mode? */
#endif /* MPPE_SUPPORT */

  u16_t  listen_time;                 /* time to listen first (ms), waiting for peer to send LCP packet */

#if PPP_IDLETIMELIMIT
  u16_t  idle_time_limit;             /* Disconnect if idle for this many seconds */
#endif /* PPP_IDLETIMELIMIT */
#if PPP_MAXCONNECT
  u32_t  maxconnect;                  /* Maximum connect time (seconds) */
#endif /* PPP_MAXCONNECT */

#if PPP_AUTH_SUPPORT
  /* auth data */
  const char  *user;                   /* Username for PAP */
  const char  *passwd;                 /* Password for PAP, secret for CHAP */
#if PPP_REMOTENAME
  char  remote_name[MAXNAMELEN   + 1]; /* Peer's name for authentication */
#endif /* PPP_REMOTENAME */

#if PAP_SUPPORT
  u8_t  pap_timeout_time;        /* Timeout (seconds) for auth-req retrans. */
  u8_t  pap_max_transmits;       /* Number of auth-reqs sent */
#if PPP_SERVER
  u8_t  pap_req_timeout;         /* Time to wait for auth-req from peer */
#endif /* PPP_SERVER */
#endif /* PAP_SUPPPORT */

#if CHAP_SUPPORT
  u8_t  chap_timeout_time;       /* Timeout (seconds) for retransmitting req */
  u8_t  chap_max_transmits;      /* max # times to send challenge */
#if PPP_SERVER
  u8_t  chap_rechallenge_time;   /* Time to wait for auth-req from peer */
#endif /* PPP_SERVER */
#endif /* CHAP_SUPPPORT */

#if EAP_SUPPORT
  u8_t  eap_req_time;            /* Time to wait (for retransmit/fail) */
  u8_t  eap_allow_req;           /* Max Requests allowed */
#if PPP_SERVER
  u8_t  eap_timeout_time;        /* Time to wait (for retransmit/fail) */
  u8_t  eap_max_transmits;       /* Max Requests allowed */
#endif /* PPP_SERVER */
#endif /* EAP_SUPPORT */

#endif /* PPP_AUTH_SUPPORT */

  u8_t  fsm_timeout_time;            /* Timeout time in seconds */
  u8_t  fsm_max_conf_req_transmits;  /* Maximum Configure-Request transmissions */
  u8_t  fsm_max_term_transmits;      /* Maximum Terminate-Request transmissions */
  u8_t  fsm_max_nak_loops;           /* Maximum number of nak loops tolerated */

  u8_t  lcp_loopbackfail;     /* Number of times we receive our magic number from the peer
                                 before deciding the link is looped-back. */
  u8_t  lcp_echo_interval;    /* Interval between LCP echo-requests */
  u8_t  lcp_echo_fails;       /* Tolerance to unanswered echo-requests */

} ppp_settings;

#if PPP_SERVER
struct ppp_addrs {
#if PPP_IPV4_SUPPORT
  ip4_addr_t our_ipaddr, his_ipaddr, netmask;
#if LWIP_DNS
  ip4_addr_t dns1, dns2;
#endif /* LWIP_DNS */
#endif /* PPP_IPV4_SUPPORT */
#if PPP_IPV6_SUPPORT
  ip6_addr_t our6_ipaddr, his6_ipaddr;
#endif /* PPP_IPV6_SUPPORT */
};
#endif /* PPP_SERVER */

/*
 * PPP interface control block.
 */
struct ppp_pcb_s {
  ppp_settings settings;
  const struct link_callbacks *link_cb;
  void *link_ctx_cb;
  void (*link_status_cb)(ppp_pcb *pcb, int err_code, void *ctx);  /* Status change callback */
#if PPP_NOTIFY_PHASE
  void (*notify_phase_cb)(ppp_pcb *pcb, u8_t phase, void *ctx);   /* Notify phase callback */
#endif /* PPP_NOTIFY_PHASE */
  void *ctx_cb;                  /* Callbacks optional pointer */
  struct netif *netif;           /* PPP interface */
  u8_t phase;                    /* where the link is at */
  u8_t err_code;                 /* Code indicating why interface is down. */

  /* flags */
#if PPP_IPV4_SUPPORT
  unsigned int ask_for_local           :1; /* request our address from peer */
  unsigned int ipcp_is_open            :1; /* haven't called np_finished() */
  unsigned int ipcp_is_up              :1; /* have called ipcp_up() */
  unsigned int if4_up                  :1; /* True when the IPv4 interface is up. */
#if 0 /* UNUSED - PROXY ARP */
  unsigned int proxy_arp_set           :1; /* Have created proxy arp entry */
#endif /* UNUSED - PROXY ARP */
#endif /* PPP_IPV4_SUPPORT */
#if PPP_IPV6_SUPPORT
  unsigned int ipv6cp_is_up            :1; /* have called ip6cp_up() */
  unsigned int if6_up                  :1; /* True when the IPv6 interface is up. */
#endif /* PPP_IPV6_SUPPORT */
  unsigned int lcp_echo_timer_running  :1; /* set if a timer is running */
#if VJ_SUPPORT
  unsigned int vj_enabled              :1; /* Flag indicating VJ compression enabled. */
#endif /* VJ_SUPPORT */
#if CCP_SUPPORT
  unsigned int ccp_all_rejected        :1; /* we rejected all peer's options */
#endif /* CCP_SUPPORT */
#if MPPE_SUPPORT
  unsigned int mppe_keys_set           :1; /* Have the MPPE keys been set? */
#endif /* MPPE_SUPPORT */

#if PPP_AUTH_SUPPORT
  /* auth data */
#if PPP_SERVER && defined(HAVE_MULTILINK)
  char peer_authname[MAXNAMELEN + 1]; /* The name by which the peer authenticated itself to us. */
#endif /* PPP_SERVER && defined(HAVE_MULTILINK) */
  u16_t auth_pending;        /* Records which authentication operations haven't completed yet. */
  u16_t auth_done;           /* Records which authentication operations have been completed. */

#if PAP_SUPPORT
  upap_state upap;           /* PAP data */
#endif /* PAP_SUPPORT */

#if CHAP_SUPPORT
  chap_client_state chap_client;  /* CHAP client data */
#if PPP_SERVER
  chap_server_state chap_server;  /* CHAP server data */
#endif /* PPP_SERVER */
#endif /* CHAP_SUPPORT */

#if EAP_SUPPORT
  eap_state eap;            /* EAP data */
#endif /* EAP_SUPPORT */
#endif /* PPP_AUTH_SUPPORT */

  fsm lcp_fsm;                   /* LCP fsm structure */
  lcp_options lcp_wantoptions;   /* Options that we want to request */
  lcp_options lcp_gotoptions;    /* Options that peer ack'd */
  lcp_options lcp_allowoptions;  /* Options we allow peer to request */
  lcp_options lcp_hisoptions;    /* Options that we ack'd */
  u16_t peer_mru;                /* currently negotiated peer MRU */
  u8_t lcp_echos_pending;        /* Number of outstanding echo msgs */
  u8_t lcp_echo_number;          /* ID number of next echo frame */

  u8_t num_np_open;              /* Number of network protocols which we have opened. */
  u8_t num_np_up;                /* Number of network protocols which have come up. */

#if VJ_SUPPORT
  struct vjcompress vj_comp;     /* Van Jacobson compression header. */
#endif /* VJ_SUPPORT */

#if CCP_SUPPORT
  fsm ccp_fsm;                   /* CCP fsm structure */
  ccp_options ccp_wantoptions;   /* what to request the peer to use */
  ccp_options ccp_gotoptions;    /* what the peer agreed to do */
  ccp_options ccp_allowoptions;  /* what we'll agree to do */
  ccp_options ccp_hisoptions;    /* what we agreed to do */
  u8_t ccp_localstate;           /* Local state (mainly for handling reset-reqs and reset-acks). */
  u8_t ccp_receive_method;       /* Method chosen on receive path */
  u8_t ccp_transmit_method;      /* Method chosen on transmit path */
#if MPPE_SUPPORT
  ppp_mppe_state mppe_comp;      /* MPPE "compressor" structure */
  ppp_mppe_state mppe_decomp;    /* MPPE "decompressor" structure */
#endif /* MPPE_SUPPORT */
#endif /* CCP_SUPPORT */

#if PPP_IPV4_SUPPORT
  fsm ipcp_fsm;                   /* IPCP fsm structure */
  ipcp_options ipcp_wantoptions;  /* Options that we want to request */
  ipcp_options ipcp_gotoptions;   /* Options that peer ack'd */
  ipcp_options ipcp_allowoptions; /* Options we allow peer to request */
  ipcp_options ipcp_hisoptions;   /* Options that we ack'd */
#endif /* PPP_IPV4_SUPPORT */

#if PPP_IPV6_SUPPORT
  fsm ipv6cp_fsm;                     /* IPV6CP fsm structure */
  ipv6cp_options ipv6cp_wantoptions;  /* Options that we want to request */
  ipv6cp_options ipv6cp_gotoptions;   /* Options that peer ack'd */
  ipv6cp_options ipv6cp_allowoptions; /* Options we allow peer to request */
  ipv6cp_options ipv6cp_hisoptions;   /* Options that we ack'd */
#endif /* PPP_IPV6_SUPPORT */
};

/************************
 *** PUBLIC FUNCTIONS ***
 ************************/

/*
 * WARNING: For multi-threads environment, all ppp_set_* functions most
 * only be called while the PPP is in the dead phase (i.e. disconnected).
 */

#if PPP_AUTH_SUPPORT
/*
 * Set PPP authentication.
 *
 * Warning: Using PPPAUTHTYPE_ANY might have security consequences.
 * RFC 1994 says:
 *
 * In practice, within or associated with each PPP server, there is a
 * database which associates "user" names with authentication
 * information ("secrets").  It is not anticipated that a particular
 * named user would be authenticated by multiple methods.  This would
 * make the user vulnerable to attacks which negotiate the least secure
 * method from among a set (such as PAP rather than CHAP).  If the same
 * secret was used, PAP would reveal the secret to be used later with
 * CHAP.
 *
 * Instead, for each user name there should be an indication of exactly
 * one method used to authenticate that user name.  If a user needs to
 * make use of different authentication methods under different
 * circumstances, then distinct user names SHOULD be employed, each of
 * which identifies exactly one authentication method.
 *
 * Default is none auth type, unset (NULL) user and passwd.
 */
#define PPPAUTHTYPE_NONE      0x00
#define PPPAUTHTYPE_PAP       0x01
#define PPPAUTHTYPE_CHAP      0x02
#define PPPAUTHTYPE_MSCHAP    0x04
#define PPPAUTHTYPE_MSCHAP_V2 0x08
#define PPPAUTHTYPE_EAP       0x10
#define PPPAUTHTYPE_ANY       0xff
void ppp_set_auth(ppp_pcb *pcb, u8_t authtype, const char *user, const char *passwd);

/*
 * If set, peer is required to authenticate. This is mostly necessary for PPP server support.
 *
 * Default is false.
 */
#define ppp_set_auth_required(ppp, boolval) (ppp->settings.auth_required = boolval)
#endif /* PPP_AUTH_SUPPORT */

#if PPP_IPV4_SUPPORT
/*
 * Set PPP interface "our" and "his" IPv4 addresses. This is mostly necessary for PPP server
 * support but it can also be used on a PPP link where each side choose its own IP address.
 *
 * Default is unset (0.0.0.0).
 */
#define ppp_set_ipcp_ouraddr(ppp, addr) do { ppp->ipcp_wantoptions.ouraddr = ip4_addr_get_u32(addr); \
                                             ppp->ask_for_local = ppp->ipcp_wantoptions.ouraddr != 0; } while(0)
#define ppp_set_ipcp_hisaddr(ppp, addr) (ppp->ipcp_wantoptions.hisaddr = ip4_addr_get_u32(addr))
#if LWIP_DNS
/*
 * Set DNS server addresses that are sent if the peer asks for them. This is mostly necessary
 * for PPP server support.
 *
 * Default is unset (0.0.0.0).
 */
#define ppp_set_ipcp_dnsaddr(ppp, index, addr) (ppp->ipcp_allowoptions.dnsaddr[index] = ip4_addr_get_u32(addr))

/*
 * If set, we ask the peer for up to 2 DNS server addresses. Received DNS server addresses are
 * registered using the dns_setserver() function.
 *
 * Default is false.
 */
#define ppp_set_usepeerdns(ppp, boolval) (ppp->settings.usepeerdns = boolval)
#endif /* LWIP_DNS */
#endif /* PPP_IPV4_SUPPORT */

#if MPPE_SUPPORT
/* Disable MPPE (Microsoft Point to Point Encryption). This parameter is exclusive. */
#define PPP_MPPE_DISABLE           0x00
/* Require the use of MPPE (Microsoft Point to Point Encryption). */
#define PPP_MPPE_ENABLE            0x01
/* Allow MPPE to use stateful mode. Stateless mode is still attempted first. */
#define PPP_MPPE_ALLOW_STATEFUL    0x02
/* Refuse the use of MPPE with 40-bit encryption. Conflict with PPP_MPPE_REFUSE_128. */
#define PPP_MPPE_REFUSE_40         0x04
/* Refuse the use of MPPE with 128-bit encryption. Conflict with PPP_MPPE_REFUSE_40. */
#define PPP_MPPE_REFUSE_128        0x08
/*
 * Set MPPE configuration
 *
 * Default is disabled.
 */
void ppp_set_mppe(ppp_pcb *pcb, u8_t flags);
#endif /* MPPE_SUPPORT */

/*
 * Wait for up to intval milliseconds for a valid PPP packet from the peer.
 * At the end of this  time, or when a valid PPP packet is received from the
 * peer, we commence negotiation by sending our first LCP packet.
 *
 * Default is 0.
 */
#define ppp_set_listen_time(ppp, intval) (ppp->settings.listen_time = intval)

/*
 * If set, we will attempt to initiate a connection but if no reply is received from
 * the peer, we will then just wait passively for a valid LCP packet from the peer.
 *
 * Default is false.
 */
#define ppp_set_passive(ppp, boolval) (ppp->lcp_wantoptions.passive = boolval)

/*
 * If set, we will not transmit LCP packets to initiate a connection until a valid
 * LCP packet is received from the peer. This is what we usually call the server mode.
 *
 * Default is false.
 */
#define ppp_set_silent(ppp, boolval) (ppp->lcp_wantoptions.silent = boolval)

/*
 * If set, enable protocol field compression negotiation in both the receive and
 * the transmit direction.
 *
 * Default is true.
 */
#define ppp_set_neg_pcomp(ppp, boolval) (ppp->lcp_wantoptions.neg_pcompression = \
                                         ppp->lcp_allowoptions.neg_pcompression = boolval)

/*
 * If set, enable Address/Control compression in both the receive and the transmit
 * direction.
 *
 * Default is true.
 */
#define ppp_set_neg_accomp(ppp, boolval) (ppp->lcp_wantoptions.neg_accompression = \
                                          ppp->lcp_allowoptions.neg_accompression = boolval)

/*
 * If set, enable asyncmap negotiation. Otherwise forcing all control characters to
 * be escaped for both the transmit and the receive direction.
 *
 * Default is true.
 */
#define ppp_set_neg_asyncmap(ppp, boolval) (ppp->lcp_wantoptions.neg_asyncmap = \
                                            ppp->lcp_allowoptions.neg_asyncmap = boolval)

/*
 * This option sets the Async-Control-Character-Map (ACCM) for this end of the link.
 * The ACCM is a set of 32 bits, one for each of the ASCII control characters with
 * values from 0 to 31, where a 1 bit  indicates that the corresponding control
 * character should not be used in PPP packets sent to this system. The map is
 * an unsigned 32 bits integer where the least significant bit (00000001) represents
 * character 0 and the most significant bit (80000000) represents character 31.
 * We will then ask the peer to send these characters as a 2-byte escape sequence.
 *
 * Default is 0.
 */
#define ppp_set_asyncmap(ppp, intval) (ppp->lcp_wantoptions.asyncmap = intval)

/*
 * Set a PPP interface as the default network interface
 * (used to output all packets for which no specific route is found).
 */
#define ppp_set_default(ppp)         netif_set_default(ppp->netif)

#if PPP_NOTIFY_PHASE
/*
 * Set a PPP notify phase callback.
 *
 * This can be used for example to set a LED pattern depending on the
 * current phase of the PPP session.
 */
typedef void (*ppp_notify_phase_cb_fn)(ppp_pcb *pcb, u8_t phase, void *ctx);
void ppp_set_notify_phase_callback(ppp_pcb *pcb, ppp_notify_phase_cb_fn notify_phase_cb);
#endif /* PPP_NOTIFY_PHASE */

/*
 * Initiate a PPP connection.
 *
 * This can only be called if PPP is in the dead phase.
 *
 * Holdoff is the time to wait (in seconds) before initiating
 * the connection.
 *
 * If this port connects to a modem, the modem connection must be
 * established before calling this.
 */
err_t ppp_connect(ppp_pcb *pcb, u16_t holdoff);

#if PPP_SERVER
/*
 * Listen for an incoming PPP connection.
 *
 * This can only be called if PPP is in the dead phase.
 *
 * If this port connects to a modem, the modem connection must be
 * established before calling this.
 */
err_t ppp_listen(ppp_pcb *pcb);
#endif /* PPP_SERVER */

/*
 * Initiate the end of a PPP connection.
 * Any outstanding packets in the queues are dropped.
 *
 * Setting nocarrier to 1 close the PPP connection without initiating the
 * shutdown procedure. Always using nocarrier = 0 is still recommended,
 * this is going to take a little longer time if your link is down, but
 * is a safer choice for the PPP state machine.
 *
 * Return 0 on success, an error code on failure.
 */
err_t ppp_close(ppp_pcb *pcb, u8_t nocarrier);

/*
 * Release the control block.
 *
 * This can only be called if PPP is in the dead phase.
 *
 * You must use ppp_close() before if you wish to terminate
 * an established PPP session.
 *
 * Return 0 on success, an error code on failure.
 */
err_t ppp_free(ppp_pcb *pcb);

/*
 * PPP IOCTL commands.
 *
 * Get the up status - 0 for down, non-zero for up.  The argument must
 * point to an int.
 */
#define PPPCTLG_UPSTATUS 0

/*
 * Get the PPP error code.  The argument must point to an int.
 * Returns a PPPERR_* value.
 */
#define PPPCTLG_ERRCODE  1

/*
 * Get the fd associated with a PPP over serial
 */
#define PPPCTLG_FD       2

/*
 * Get and set parameters for the given connection.
 * Return 0 on success, an error code on failure.
 */
err_t ppp_ioctl(ppp_pcb *pcb, u8_t cmd, void *arg);

/* Get the PPP netif interface */
#define ppp_netif(ppp)               (ppp->netif)

/* Set an lwIP-style status-callback for the selected PPP device */
#define ppp_set_netif_statuscallback(ppp, status_cb)       \
        netif_set_status_callback(ppp->netif, status_cb);

/* Set an lwIP-style link-callback for the selected PPP device */
#define ppp_set_netif_linkcallback(ppp, link_cb)           \
        netif_set_link_callback(ppp->netif, link_cb);

#ifdef __cplusplus
}
#endif

#endif /* PPP_H */

#endif /* PPP_SUPPORT */