devsdp.c

著名操作系统Plan 9的第三版的部分核心源代码。现在很难找到了。Plan 9是bell实验室开发的Unix后继者。

#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/netif.h"
#include "../port/error.h"

#include	<libsec.h>
#include "../port/thwack.h"

/*
 * sdp - secure datagram protocol
 */

typedef struct Sdp Sdp;
typedef struct Conv Conv;
typedef struct OneWay OneWay;
typedef struct Stats Stats;
typedef struct AckPkt AckPkt;
typedef struct Algorithm Algorithm;
typedef struct CipherRc4 CipherRc4;

enum
{
	Qtopdir=	1,		/* top level directory */

	Qsdpdir,			/* sdp directory */
	Qclone,
	Qlog,

	Qconvdir,			/* directory per conversation */
	Qctl,
	Qdata,				/* unreliable packet channel */
	Qcontrol,			/* reliable control channel */
	Qstatus,
	Qstats,
	Qrstats,

	MaxQ,

	Maxconv= 256,		// power of 2
	Nfs= 4,				// number of file systems
	MaxRetries=	12,
	KeepAlive = 120,	// keep alive in seconds
	SecretLength= 32,	// a secret per direction
	SeqMax = (1<<24),
	SeqWindow = 32,
	NCompStats = 8,
};

#define TYPE(x) 	((x).path & 0xff)
#define CONV(x) 	(((x).path >> 8)&(Maxconv-1))
#define QID(x, y) 	(((x)<<8) | (y))

struct Stats
{
	ulong	outPackets;
	ulong	outDataPackets;
	ulong	outDataBytes;
	ulong	outCompDataBytes;
	ulong	outCompBytes;
	ulong	outCompStats[NCompStats];
	ulong	inPackets;
	ulong	inDataPackets;
	ulong	inDataBytes;
	ulong	inCompDataBytes;
	ulong	inMissing;
	ulong	inDup;
	ulong	inReorder;
	ulong	inBadComp;
	ulong	inBadAuth;
	ulong	inBadSeq;
	ulong	inBadOther;
};

struct OneWay
{
	Rendez	statsready;

	ulong	seqwrap;	// number of wraps of the sequence number
	ulong	seq;
	ulong	window;

	uchar	secret[SecretLength];

	QLock	controllk;
	Rendez	controlready;
	Block	*controlpkt;		// control channel
	ulong	controlseq;

	void	*cipherstate;	// state cipher
	int		cipherivlen;	// initial vector length
	int		cipherblklen;	// block length
	int		(*cipher)(OneWay*, uchar *buf, int len);

	void	*authstate;		// auth state
	int		authlen;		// auth data length in bytes
	int		(*auth)(OneWay*, uchar *buf, int len);

	void	*compstate;
	int		(*comp)(Conv*, int subtype, ulong seq, Block **);
};

// conv states
enum {
	CFree,
	CInit,
	CDial,
	CAccept,
	COpen,
	CLocalClose,
	CRemoteClose,
	CClosed,
};

struct Conv {
	QLock;
	Sdp	*sdp;
	int	id;

	int ref;	// holds conv up

	int state;

	int dataopen;	// ref count of opens on Qdata
	int controlopen;	// ref count of opens on Qcontrol
	int reader;		// reader proc has been started

	Stats	lstats;
	Stats	rstats;
	
	ulong	lastrecv;	// time last packet was received 
	ulong	timeout;
	int		retries;

	// the following pair uniquely define conversation on this port
	ulong dialid;
	ulong acceptid;

	QLock readlk;		// protects readproc
	Proc *readproc;

	Chan *chan;		// packet channel
	char *channame;

	char owner[NAMELEN];		/* protections */
	int	perm;

	Algorithm *auth;
	Algorithm *cipher;
	Algorithm *comp;

	int drop;

	OneWay	in;
	OneWay	out;
};

struct Sdp {
	QLock;
	Log;
	Rendez	vous;			/* used by sdpackproc */
	int	nconv;
	Conv *conv[Maxconv];
	int ackproc;
};

enum {
	TConnect,
	TControl,
	TData,
	TCompData,
};

enum {
	ControlMesg,
	ControlAck,
};

enum {
	ThwackU,
	ThwackC,
};

enum {
	ConOpenRequest,
	ConOpenAck,
	ConOpenAckAck,
	ConClose,
	ConCloseAck,
	ConReset,
};

struct AckPkt
{
	uchar	cseq[4];
	uchar	outPackets[4];
	uchar	outDataPackets[4];
	uchar	outDataBytes[4];
	uchar	outCompDataBytes[4];
	uchar	outCompStats[4*NCompStats];
	uchar	inPackets[4];
	uchar	inDataPackets[4];
	uchar	inDataBytes[4];
	uchar	inCompDataBytes[4];
	uchar	inMissing[4];
	uchar	inDup[4];
	uchar	inReorder[4];
	uchar	inBadComp[4];
	uchar	inBadAuth[4];
	uchar	inBadSeq[4];
	uchar	inBadOther[4];
};

struct Algorithm
{
	char 	*name;
	int		keylen;		// in bytes
	void	(*init)(Conv*);
};

enum {
	RC4forward	= 10*1024*1024,	// maximum skip forward
	RC4back = 100*1024,		// maximum look back
};

struct CipherRc4
{
	ulong cseq;	// current byte sequence number
	RC4state current;

	int ovalid;	// old is valid
	ulong lgseq; // last good sequence
	ulong oseq;	// old byte sequence number
	RC4state old;
};

static Dirtab sdpdirtab[]={
	"log",		{Qlog},		0,	0666,
	"clone",	{Qclone},		0,	0666,
};

static Dirtab convdirtab[]={
	"ctl",		{Qctl},	0,	0666,
	"data",		{Qdata},	0,	0666,
	"control",	{Qcontrol},	0,	0666,
	"status",	{Qstatus},	0,	0444,
	"stats",	{Qstats},	0,	0444,
	"rstats",	{Qrstats},	0,	0444,
};

static int m2p[] = {
	[OREAD]		4,
	[OWRITE]	2,
	[ORDWR]		6
};

enum {
	Logcompress=	(1<<0),
	Logauth=	(1<<1),
	Loghmac=	(1<<2),
};

static Logflag logflags[] =
{
	{ "compress",	Logcompress, },
	{ "auth",	Logauth, },
	{ "hmac",	Loghmac, },
	{ nil,		0, },
};

static Dirtab	*dirtab[MaxQ];
static Sdp sdptab[Nfs];
static char *convstatename[] = {
	[CFree]		"Free",
	[CInit]		"Init",
	[CDial]		"Dial",
	[CAccept]	"Accept",
	[COpen]		"Open",
	[CLocalClose] "LocalClose",
	[CRemoteClose] "RemoteClose",
	[CClosed]	"Closed",
};

static int sdpgen(Chan *c, Dirtab*, int, int s, Dir *dp);
static Conv *sdpclone(Sdp *sdp);
static void sdpackproc(void *a);
static void onewaycleanup(OneWay *ow);
static int readready(void *a);
static int controlread();
static void convsetstate(Conv *c, int state);
static Block *readcontrol(Conv *c, int n);
static void writecontrol(Conv *c, void *p, int n, int wait);
static Block *readdata(Conv *c, int n);
static long writedata(Conv *c, Block *b);
static void convderef(Conv *c);
static Block *conviput(Conv *c, Block *b, int control);
static void conviconnect(Conv *c, int op, Block *b);
static void convicontrol(Conv *c, int op, Block *b);
static Block *convicomp(Conv *c, int op, ulong, Block *b);
static void convoput(Conv *c, int type, int subtype, Block *b);
static void convoconnect(Conv *c, int op, ulong dialid, ulong acceptid);
static void convopenchan(Conv *c, char *path);
static void convstats(Conv *c, int local, char *buf, int n);
static void convreader(void *a);

static void setalg(Conv *c, char *name, Algorithm *tab, Algorithm **);
static void setsecret(OneWay *cc, char *secret);

static void nullcipherinit(Conv*c);
static void descipherinit(Conv*c);
static void rc4cipherinit(Conv*c);
static void nullauthinit(Conv*c);
static void shaauthinit(Conv*c);
static void md5authinit(Conv*c);
static void nullcompinit(Conv*c);
static void thwackcompinit(Conv*c);

static Algorithm cipheralg[] =
{
	"null",			0,	nullcipherinit,
	"des_56_cbc",	7,	descipherinit,
	"rc4_128",		16,	rc4cipherinit,
	"rc4_256",		32,	rc4cipherinit,
	nil,			0,	nil,
};

static Algorithm authalg[] =
{
	"null",			0,	nullauthinit,
	"hmac_sha1_96",	16,	shaauthinit,
	"hmac_md5_96",	16,	md5authinit,
	nil,			0,	nil,
};

static Algorithm compalg[] =
{
	"null",			0,	nullcompinit,
	"thwack",		0,	thwackcompinit,
	nil,			0,	nil,
};


static void
sdpinit(void)
{
	int i;
	Dirtab *dt;
	
	// setup dirtab with non directory entries
	for(i=0; i<nelem(sdpdirtab); i++) {
		dt = sdpdirtab + i;
		dirtab[TYPE(dt->qid)] = dt;
	}

	for(i=0; i<nelem(convdirtab); i++) {
		dt = convdirtab + i;
		dirtab[TYPE(dt->qid)] = dt;
	}

}

static Chan*
sdpattach(char* spec)
{
	Chan *c;
	int dev;
	char buf[100];
	Sdp *sdp;
	int start;

	dev = atoi(spec);
	if(dev<0 || dev >= Nfs)
		error("bad specification");

	c = devattach('E', spec);
	c->qid = (Qid){QID(0, Qtopdir)|CHDIR, 0};
	c->dev = dev;

	sdp = sdptab + dev;
	qlock(sdp);
	start = sdp->ackproc == 0;
	sdp->ackproc = 1;
	qunlock(sdp);

	if(start) {
		snprint(buf, sizeof(buf), "sdpackproc%d", dev);
		kproc(buf, sdpackproc, sdp);
	}
	
	return c;
}

static int
sdpwalk(Chan *c, char *name)
{
	return devwalk(c, name, 0, 0, sdpgen);
}

static void
sdpstat(Chan* c, char* db)
{
	devstat(c, db, nil, 0, sdpgen);
}


static Chan*
sdpopen(Chan* ch, int omode)
{
	int perm;
	Sdp *sdp;
	Conv *c;

	omode &= 3;
	perm = m2p[omode];
	USED(perm);

	sdp = sdptab + ch->dev;

	switch(TYPE(ch->qid)) {
	default:
		break;
	case Qtopdir:
	case Qsdpdir:
	case Qconvdir:
		if(omode != OREAD)
			error(Eperm);
		break;
	case Qlog:
		logopen(sdp);
		break;
	case Qclone:
		c = sdpclone(sdp);
		if(c == nil)
			error(Enodev);
		ch->qid.path = QID(c->id, Qctl);
		break;
	case Qdata:
	case Qctl:
	case Qstatus:
	case Qcontrol:
	case Qstats:
	case Qrstats:
		c = sdp->conv[CONV(ch->qid)];
		qlock(c);
		if(waserror()) {
			qunlock(c);
			nexterror();
		}
		if((perm & (c->perm>>6)) != perm)
		if(strcmp(up->user, c->owner) != 0 || (perm & c->perm) != perm)
				error(Eperm);

		c->ref++;
		if(TYPE(ch->qid) == Qdata) {
			c->dataopen++;
			// kill reader if Qdata is opened for the first time
			if(c->dataopen == 1)
			if(c->readproc != nil)
				postnote(c->readproc, 1, "interrupt", 0);
		} else if(TYPE(ch->qid) == Qcontrol) {	
			c->controlopen++;
		}
		qunlock(c);
		poperror();
		break;
	}
	ch->mode = openmode(omode);
	ch->flag |= COPEN;
	ch->offset = 0;
	return ch;
}

static void
sdpclose(Chan* ch)
{
	Sdp *sdp  = sdptab + ch->dev;
	Conv *c;

	if(!(ch->flag & COPEN))
		return;
	switch(TYPE(ch->qid)) {
	case Qlog:
		logclose(sdp);
		break;
	case Qctl:
	case Qstatus:
	case Qstats:
	case Qrstats:
		c = sdp->conv[CONV(ch->qid)];
		qlock(c);
		convderef(c);
		qunlock(c);
		break;

	case Qdata:
		c = sdp->conv[CONV(ch->qid)];
		qlock(c);
		c->dataopen--;
		convderef(c);
		if(c->dataopen == 0)
		if(c->reader == 0)
		if(c->chan != nil)
		if(!waserror()) {
			kproc("convreader", convreader, c);
			c->reader = 1;
			c->ref++;
			poperror();
		}
		qunlock(c);
		break;

	case Qcontrol:
		c = sdp->conv[CONV(ch->qid)];
		qlock(c);
		c->controlopen--;
		convderef(c);
		if(c->controlopen == 0 && c->ref != 0) {
			switch(c->state) {
			default:
				convsetstate(c, CClosed);
				break;
			case CAccept:
			case COpen:
				convsetstate(c, CLocalClose);
				break;
			}
		}
		qunlock(c);
		poperror();
		break;
	}
}

static long
sdpread(Chan *ch, void *a, long n, vlong off)
{
	char buf[256];
	char *s;
	Sdp *sdp = sdptab + ch->dev;
	Conv *c;
	Block *b;
	int rv;

	USED(off);
	switch(TYPE(ch->qid)) {
	default:
		error(Eperm);
	case Qtopdir:
	case Qsdpdir:
	case Qconvdir:
		return devdirread(ch, a, n, 0, 0, sdpgen);
	case Qlog:
		return logread(sdp, a, off, n);
	case Qstatus:
		c = sdp->conv[CONV(ch->qid)];
		qlock(c);
		n = readstr(off, a, n, convstatename[c->state]);
		qunlock(c);
		return n;
	case Qctl:
		sprint(buf, "%lud", CONV(ch->qid));
		return readstr(off, a, n, buf);
	case Qcontrol:
		b = readcontrol(sdp->conv[CONV(ch->qid)], n);
		if(b == nil)
			return 0;
		if(BLEN(b) < n)
			n = BLEN(b);
		memmove(a, b->rp, n);
		freeb(b);
		return n;
	case Qdata:
		b = readdata(sdp->conv[CONV(ch->qid)], n);
		if(b == nil)
			return 0;
		if(BLEN(b) < n)
			n = BLEN(b);
		memmove(a, b->rp, n);
		freeb(b);
		return n;
	case Qstats:
	case Qrstats:
		c = sdp->conv[CONV(ch->qid)];
		s = smalloc(1000);
		convstats(c, TYPE(ch->qid) == Qstats, s, 1000);
		rv = readstr(off, a, n, s);
		free(s);
		return rv;
	}
}

static Block*
sdpbread(Chan* ch, long n, ulong offset)
{
	Sdp *sdp = sdptab + ch->dev;

	if(TYPE(ch->qid) != Qdata)
		return devbread(ch, n, offset);
	return readdata(sdp->conv[CONV(ch->qid)], n);
}


static long
sdpwrite(Chan *ch, void *a, long n, vlong off)
{
	Sdp *sdp = sdptab + ch->dev;
	Cmdbuf *cb;
	char *arg0;
	char *p;
	Conv *c;
	Block *b;
	
	USED(off);
	switch(TYPE(ch->qid)) {
	default:
		error(Eperm);
	case Qctl:
		c = sdp->conv[CONV(ch->qid)];
		cb = parsecmd(a, n);
		qlock(c);
		if(waserror()) {
			qunlock(c);
			free(cb);
			nexterror();
		}
		if(cb->nf == 0)
			error("short write");
		arg0 = cb->f[0];
		if(strcmp(arg0, "accept") == 0) {
			if(cb->nf != 2)
				error("usage: accect file");
			convopenchan(c, cb->f[1]);
		} else if(strcmp(arg0, "dial") == 0) {
			if(cb->nf != 2)
				error("usage: accect file");
			convopenchan(c, cb->f[1]);
			convsetstate(c, CDial);
		} else if(strcmp(arg0, "drop") == 0) {
			if(cb->nf != 2)
				error("usage: drop permil");
			c->drop = atoi(cb->f[1]);
		} else if(strcmp(arg0, "cipher") == 0) {
			if(cb->nf != 2)
				error("usage: cipher alg");
			setalg(c, cb->f[1], cipheralg, &c->cipher);
		} else if(strcmp(arg0, "auth") == 0) {
			if(cb->nf != 2)
				error("usage: auth alg");
			setalg(c, cb->f[1], authalg, &c->auth);
		} else if(strcmp(arg0, "comp") == 0) {
			if(cb->nf != 2)
				error("usage: comp alg");
			setalg(c, cb->f[1], compalg, &c->comp);
		} else if(strcmp(arg0, "insecret") == 0) {
			if(cb->nf != 2)
				error("usage: insecret secret");
			setsecret(&c->in, cb->f[1]);
			if(c->cipher)
				c->cipher->init(c);
			if(c->auth)
				c->auth->init(c);
		} else if(strcmp(arg0, "outsecret") == 0) {
			if(cb->nf != 2)
				error("usage: outsecret secret");
			setsecret(&c->out, cb->f[1]);
			if(c->cipher)
				c->cipher->init(c);
			if(c->auth)
				c->auth->init(c);
		} else
			error("unknown control request");
		poperror();
		qunlock(c);
		free(cb);
		return n;
	case Qlog:
		cb = parsecmd(a, n);
		p = logctl(sdp, cb->nf, cb->f, logflags);
		free(cb);
		if(p != nil)
			error(p);
		return n;
	case Qcontrol:
		writecontrol(sdp->conv[CONV(ch->qid)], a, n, 0);
		return n;
	case Qdata:
		b = allocb(n);
		memmove(b->wp, a, n);
		b->wp += n;
		return writedata(sdp->conv[CONV(ch->qid)], b);
	}
}

long
sdpbwrite(Chan *ch, Block *bp, ulong offset)
{
	Sdp *sdp = sdptab + ch->dev;

	if(TYPE(ch->qid) != Qdata)
		return devbwrite(ch, bp, offset);
	return writedata(sdp->conv[CONV(ch->qid)], bp);
}

static int
sdpgen(Chan *c, Dirtab*, int, int s, Dir *dp)
{
	Sdp *sdp = sdptab + c->dev;
	int type = TYPE(c->qid);
	char buf[32];
	Dirtab *dt;
	Qid qid;

	if(s == DEVDOTDOT){
		switch(TYPE(c->qid)){
		case Qtopdir:
		case Qsdpdir:
			snprint(buf, sizeof(buf), "#E%ld", c->dev);
			devdir(c, (Qid){CHDIR|Qtopdir, 0}, buf, 0, eve, 0555, dp);
			break;
		case Qconvdir:
			snprint(buf, sizeof(buf), "%d", s);
			devdir(c, (Qid){CHDIR|Qsdpdir, 0}, buf, 0, eve, 0555, dp);
			break;
		default:
			panic("sdpwalk %lux", c->qid.path);
		}
		return 1;
	}

	switch(type) {
	default:
		// non directory entries end up here
		if(c->qid.path & CHDIR)
			panic("sdpgen: unexpected directory");	
		if(s != 0)
			return -1;
		dt = dirtab[TYPE(c->qid)];
		if(dt == nil)
			panic("sdpgen: unknown type: %d", TYPE(c->qid));
		devdir(c, c->qid, dt->name, dt->length, eve, dt->perm, dp);
		return 1;
	case Qtopdir:
		if(s != 0)
			return -1;
		devdir(c, (Qid){QID(0,Qsdpdir)|CHDIR,0}, "sdp", 0, eve, 0555, dp);
		return 1;
	case Qsdpdir:
		if(s<nelem(sdpdirtab)) {
			dt = sdpdirtab+s;
			devdir(c, dt->qid, dt->name, dt->length, eve, dt->perm, dp);
			return 1;
		}
		s -= nelem(sdpdirtab);
		if(s >= sdp->nconv)
			return -1;
		qid = (Qid){QID(s,Qconvdir)|CHDIR, 0};
		snprint(buf, sizeof(buf), "%d", s);
		devdir(c, qid, buf, 0, eve, 0555, dp);
		return 1;
	case Qconvdir:
		if(s>=nelem(convdirtab))
			return -1;
		dt = convdirtab+s;
		qid = (Qid){QID(CONV(c->qid),TYPE(dt->qid)),0};
		devdir(c, qid, dt->name, dt->length, eve, dt->perm, dp);
		return 1;
	}
}

static Conv*