typedef struct Tcpc Tcpc;

typedef struct Tcpc Tcpc;
typedef struct Pstate Pstate;
typedef struct Chap Chap;
typedef struct Qualstats Qualstats;
typedef struct Comptype Comptype;
typedef struct Uncomptype Uncomptype;
typedef struct PPP PPP;
typedef struct Lcpmsg Lcpmsg;
typedef struct Lcpopt Lcpopt;
typedef struct Qualpkt Qualpkt;
typedef struct Block Block;

typedef uchar Ipaddr[IPaddrlen];

#pragma incomplete Tcpc

/*
* data blocks
*/
struct Block
{
Block *next;
Block *flist;
Block *list; /* chain of block lists */
uchar *rptr; /* first unconsumed uchar */
uchar *wptr; /* first empty uchar */
uchar *lim; /* 1 past the end of the buffer */
uchar *base; /* start of the buffer */
uchar flags;
void *flow;
ulong pc;
ulong bsz;
};
#define BLEN(b) ((b)->wptr-(b)->rptr)

enum
{
/* block flags */
S_DELIM = (1<<0),
S_HANGUP = (1<<1),
S_RHANGUP = (1<<2),

/* queue states */
QHUNGUP = (1<<0),
QFLOW = (1<<1), /* queue is flow controlled */
};

Block* allocb(int);
void freeb(Block*);
Block* concat(Block*);
int blen(Block*);
Block* pullup(Block*, int);
Block* padb(Block*, int);
Block* btrim(Block*, int, int);
Block* copyb(Block*, int);
int pullb(Block**, int);

enum {
HDLC_frame= 0x7e,
HDLC_esc= 0x7d,

/* PPP frame fields */
PPP_addr= 0xff,
PPP_ctl= 0x3,
PPP_initfcs= 0xffff,
PPP_goodfcs= 0xf0b8,

/* PPP phases */
Pdead= 0,
Plink, /* doing LCP */
Pauth, /* doing chap */
Pnet, /* doing IPCP, CCP */
Pterm, /* closing down */

/* PPP protocol types */
Pip= 0x21, /* ip v4 */
Pipv6= 0x57, /* ip v6 */
Pvjctcp= 0x2d, /* compressing van jacobson tcp */
Pvjutcp= 0x2f, /* uncompressing van jacobson tcp */
Pcdata= 0xfd, /* compressed datagram */
Pipcp= 0x8021, /* ip control */
Pecp= 0x8053, /* encryption control */
Pccp= 0x80fd, /* compressed datagram control */
Plcp= 0xc021, /* link control */
Ppasswd= 0xc023, /* passwd authentication */
Plqm= 0xc025, /* link quality monitoring */
Pchap= 0xc223, /* challenge/response */

/* LCP codes */
Lconfreq= 1,
Lconfack= 2,
Lconfnak= 3,
Lconfrej= 4,
Ltermreq= 5,
Ltermack= 6,
Lcoderej= 7,
Lprotorej= 8,
Lechoreq= 9,
Lechoack= 10,
Ldiscard= 11,
Lresetreq= 14,
Lresetack= 15,

/* Lcp configure options */
Omtu= 1,
Octlmap= 2,
Oauth= 3,
Oquality= 4,
Omagic= 5,
Opc= 7,
Oac= 8,

/* authentication protocols */
APmd5= 5,
APmschap= 128,
APmschapv2= 129,
APpasswd= Ppasswd, /* use Pap, not Chap */

/* lcp flags */
Fmtu= 1<<Omtu,
Fctlmap= 1<<Octlmap,
Fauth= 1<<Oauth,
Fquality= 1<<Oquality,
Fmagic= 1<<Omagic,
Fpc= 1<<Opc,
Fac= 1<<Oac,

/* Chap codes */
Cchallenge= 1,
Cresponse= 2,
Csuccess= 3,
Cfailure= 4,

/* Pap codes */
Pauthreq= 1,
Pauthack= 2,
Pauthnak= 3,

/* Chap state */
Cunauth= 0,
Cchalsent,
Cauthfail,
Cauthok,

/* link states */
Sclosed= 0,
Sclosing,
Sreqsent,
Sackrcvd,
Sacksent,
Sopened,

/* ccp configure options */
Ocoui= 0, /* proprietary compression */
Ocstac= 17, /* stac electronics LZS */
Ocmppc= 18, /* microsoft ppc */
Octhwack= 31, /* thwack; unofficial */

/* ccp flags */
Fcoui= 1<<Ocoui,
Fcstac= 1<<Ocstac,
Fcmppc= 1<<Ocmppc,
Fcthwack= 1<<Octhwack,

/* ecp configure options */
Oeoui= 0, /* proprietary compression */
Oedese= 1, /* DES */

/* ecp flags */
Feoui= 1<<Oeoui,
Fedese= 1<<Oedese,

/* ipcp configure options */
Oipaddrs= 1,
Oipcompress= 2,
Oipaddr= 3,
Oipdns= 129,
Oipwins= 130,
Oipdns2= 131,
Oipwins2= 132,

/* ipcp flags */
Fipaddrs= 1<<Oipaddrs,
Fipcompress= 1<<Oipcompress,
Fipaddr= 1<<Oipaddr,
Fipdns= 1<<8, // Oipdns,
Fipwins= 1<<9, // Oipwins,
Fipdns2= 1<<10, // Oipdns2,
Fipwins2= 1<<11, // Oipwins2,

Period= 5*1000, /* period of retransmit process (in ms) */
Timeout= 20, /* xmit timeout (in Periods) */
Buflen= 4096,

MAX_STATES= 16, /* van jacobson compression states */
Defmtu= 1450, /* default that we will ask for */
Minmtu= 128, /* minimum that we will accept */
Maxmtu= 2000, /* maximum that we will accept */
};

struct Pstate
{
int proto; /* protocol type */
int timeout; /* for current state */
int rxtimeout; /* for current retransmit */
ulong flags; /* options received */
uchar id; /* id of current message */
uchar confid; /* id of current config message */
uchar termid; /* id of current termination message */
uchar rcvdconfid; /* id of last conf message received */
uchar state; /* PPP link state */
ulong optmask; /* which options to request */
int echoack; /* recieved echo ack */
int echotimeout; /* echo timeout */
};

/* server chap state */
struct Chap
{
int proto; /* chap proto */
int state; /* chap state */
uchar id; /* id of current message */
int timeout; /* for current state */
AuthInfo *ai;
Chalstate *cs;
};

struct Qualstats
{
ulong reports;
ulong packets;
ulong uchars;
ulong discards;
ulong errors;
};

struct Comptype
{
void* (*init)(PPP*);
Block* (*compress)(PPP*, ushort, Block*, int*);
Block* (*resetreq)(void*, Block*);
void (*fini)(void*);
};

struct Uncomptype
{
void* (*init)(PPP*);
Block* (*uncompress)(PPP*, Block*, int*, Block**);
void (*resetack)(void*, Block*);
void (*fini)(void*);
};

struct PPP
{
QLock;

int ipfd; /* fd to ip stack */
int ipcfd; /* fd to control channel of ip stack */
int mediain; /* fd to media */
int mediaout; /* fd to media */
char *net; /* ip stack to use */
int framing; /* non-zero to use framing characters */
Ipaddr local;
Ipaddr curlocal;
int localfrozen;
Ipaddr remote;
Ipaddr curremote;
int remotefrozen;

Ipaddr dns[2]; /* dns servers */
Ipaddr wins[2]; /* wins servers */

Block* inbuf; /* input buffer */
Block* outbuf; /* output buffer */
QLock outlock; /* and its lock */
ulong magic; /* magic number to detect loop backs */
ulong rctlmap; /* map of chars to ignore in rcvr */
ulong xctlmap; /* map of chars to excape in xmit */
int phase; /* PPP phase */
Pstate* lcp; /* lcp state */
Pstate* ccp; /* ccp state */
Pstate* ipcp; /* ipcp state */
Chap* chap; /* chap state */
Tcpc* ctcp; /* tcp compression state */
ulong mtu; /* maximum xmit size */
ulong mru; /* maximum recv size */

/* data compression */
int ctries; /* number of negotiation tries */
Comptype *ctype; /* compression virtual table */
void *cstate; /* compression state */
Uncomptype *unctype; /* uncompression virtual table */
void *uncstate; /* uncompression state */

/* encryption key */
uchar sendkey[16];
uchar recvkey[16];
int sendencrypted;

/* authentication */
char chapname[256]; /* chap system name */

/* link quality monitoring */
int period; /* lqm period */
int timeout; /* time to next lqm packet */
Qualstats in; /* local */
Qualstats out;
Qualstats pin; /* peer */
Qualstats pout;
Qualstats sin; /* saved */

struct {
ulong ipsend;
ulong iprecv;
ulong iprecvbadsrc;
ulong iprecvnotup;
ulong comp;
ulong compin;
ulong compout;
ulong compreset;
ulong uncomp;
ulong uncompin;
ulong uncompout;
ulong uncompreset;
ulong vjin;
ulong vjout;
ulong vjfail;
} stat;
};

extern Block* pppread(PPP*);
extern int pppwrite(PPP*, Block*);
extern void pppopen(PPP*, int, int, char*, Ipaddr, Ipaddr, int, int);

struct Lcpmsg
{
uchar code;
uchar id;
uchar len[2];
uchar data[1];
};

struct Lcpopt
{
uchar type;
uchar len;
uchar data[1];
};

struct Qualpkt
{
uchar magic[4];

uchar lastoutreports[4];
uchar lastoutpackets[4];
uchar lastoutuchars[4];
uchar peerinreports[4];
uchar peerinpackets[4];
uchar peerindiscards[4];
uchar peerinerrors[4];
uchar peerinuchars[4];
uchar peeroutreports[4];
uchar peeroutpackets[4];
uchar peeroutuchars[4];
};

extern Block* compress(Tcpc*, Block*, int*);
extern void compress_error(Tcpc*);
extern Tcpc* compress_init(Tcpc*);
extern int compress_negotiate(Tcpc*, uchar*);
extern Block* tcpcompress(Tcpc*, Block*, int*);
extern Block* tcpuncompress(Tcpc*, Block*, int);
extern Block* alloclcp(int, int, int, Lcpmsg**);
extern ushort ptclcsum(Block*, int, int);
extern ushort ptclbsum(uchar*, int);
extern ushort ipcsum(uchar*);

void getasymkey(uchar *key, uchar *masterkey, int send, int server);

extern Comptype cmppc;
extern Uncomptype uncmppc;

extern Comptype cthwack;
extern Uncomptype uncthwack;

extern void netlog(char*, ...);
#pragma varargck argpos netlog 1

extern char *LOG;