rpc.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

#include <u.h>
#include <libc.h>
#include <thread.h>
#include <sunrpc.h>

/*
 * RPC protocol constants
 */
enum
{
	RpcVersion = 2,

	/* msg type */
	MsgCall = 0,
	MsgReply = 1,

	/* reply stat */
	MsgAccepted = 0,
	MsgDenied = 1,

	/* accept stat */
	MsgSuccess = 0,
	MsgProgUnavail = 1,
	MsgProgMismatch = 2,
	MsgProcUnavail = 3,
	MsgGarbageArgs = 4,
	MsgSystemErr = 5,

	/* reject stat */
	MsgRpcMismatch = 0,
	MsgAuthError = 1,

	/* msg auth xxx */
	MsgAuthOk = 0,
	MsgAuthBadCred = 1,
	MsgAuthRejectedCred = 2,
	MsgAuthBadVerf = 3,
	MsgAuthRejectedVerf = 4,
	MsgAuthTooWeak = 5,
	MsgAuthInvalidResp = 6,
	MsgAuthFailed = 7,
};

SunStatus
sunRpcPack(uchar *a, uchar *ea, uchar **pa, SunRpc *rpc)
{
	u32int x;

	if(sunUint32Pack(a, ea, &a, &rpc->xid) < 0)
		goto Err;
	if(rpc->iscall){
		if(sunUint32Pack(a, ea, &a, (x=MsgCall, &x)) < 0
		|| sunUint32Pack(a, ea, &a, (x=RpcVersion, &x)) < 0
		|| sunUint32Pack(a, ea, &a, &rpc->prog) < 0
		|| sunUint32Pack(a, ea, &a, &rpc->vers) < 0
		|| sunUint32Pack(a, ea, &a, &rpc->proc) < 0
		|| sunAuthInfoPack(a, ea, &a, &rpc->cred) < 0
		|| sunAuthInfoPack(a, ea, &a, &rpc->verf) < 0
		|| sunFixedOpaquePack(a, ea, &a, rpc->data, rpc->ndata) < 0)
			goto Err;
	}else{
		if(sunUint32Pack(a, ea, &a, (x=MsgReply, &x)) < 0)
			goto Err;
		switch(rpc->status&0xF0000){
		case 0:
		case SunAcceptError:
			if(sunUint32Pack(a, ea, &a, (x=MsgAccepted, &x)) < 0
			|| sunAuthInfoPack(a, ea, &a, &rpc->verf) < 0)
				goto Err;
			break;
		default:
			if(sunUint32Pack(a, ea, &a, (x=MsgDenied, &x)) < 0)
				goto Err;
			break;
		}

		switch(rpc->status){
		case SunSuccess:
			if(sunUint32Pack(a, ea, &a, (x=MsgSuccess, &x)) < 0
			|| sunFixedOpaquePack(a, ea, &a, rpc->data, rpc->ndata) < 0)
				goto Err;
			break;
		case SunRpcMismatch:
		case SunProgMismatch:
			if(sunUint32Pack(a, ea, &a, (x=rpc->status&0xFFFF, &x)) < 0
			|| sunUint32Pack(a, ea, &a, &rpc->low) < 0
			|| sunUint32Pack(a, ea, &a, &rpc->high) < 0)
				goto Err;
			break;
		default:
			if(sunUint32Pack(a, ea, &a, (x=rpc->status&0xFFFF, &x)) < 0)
				goto Err;
			break;
		}
	}
	*pa = a;
	return SunSuccess;

Err:
	*pa = ea;
	return SunGarbageArgs;
}

uint
sunRpcSize(SunRpc *rpc)
{
	uint a;

	a = 4;
	if(rpc->iscall){
		a += 5*4;
		a += sunAuthInfoSize(&rpc->cred);
		a += sunAuthInfoSize(&rpc->verf);
		a += sunFixedOpaqueSize(rpc->ndata);
	}else{
		a += 4;
		switch(rpc->status&0xF0000){
		case 0:
		case SunAcceptError:
			a += 4+sunAuthInfoSize(&rpc->verf);
			break;
		default:
			a += 4;
			break;
		}

		switch(rpc->status){
		case SunSuccess:
			a += 4+sunFixedOpaqueSize(rpc->ndata);
			break;
		case SunRpcMismatch:
		case SunProgMismatch:
			a += 3*4;
		default:
			a += 4;
		}
	}
	return a;
}

SunStatus
sunRpcUnpack(uchar *a, uchar *ea, uchar **pa, SunRpc *rpc)
{
	u32int x;

	memset(rpc, 0, sizeof *rpc);
	if(sunUint32Unpack(a, ea, &a, &rpc->xid) < 0
	|| sunUint32Unpack(a, ea, &a, &x) < 0)
		goto Err;

	switch(x){
	default:
		goto Err;
	case MsgCall:
		rpc->iscall = 1;
		if(sunUint32Unpack(a, ea, &a, &x) < 0 || x != RpcVersion
		|| sunUint32Unpack(a, ea, &a, &rpc->prog) < 0
		|| sunUint32Unpack(a, ea, &a, &rpc->vers) < 0
		|| sunUint32Unpack(a, ea, &a, &rpc->proc) < 0
		|| sunAuthInfoUnpack(a, ea, &a, &rpc->cred) < 0
		|| sunAuthInfoUnpack(a, ea, &a, &rpc->verf) < 0)
			goto Err;
		rpc->ndata = ea-a;
		rpc->data = a;
		a = ea;
		break;

	case MsgReply:
		rpc->iscall = 0;
		if(sunUint32Unpack(a, ea, &a, &x) < 0)
			goto Err;
		switch(x){
		default:
			goto Err;
		case MsgAccepted:
			if(sunAuthInfoUnpack(a, ea, &a, &rpc->verf) < 0
			|| sunUint32Unpack(a, ea, &a, &x) < 0)
				goto Err;
			switch(x){
			case MsgSuccess:
				rpc->status = SunSuccess;
				rpc->ndata = ea-a;
				rpc->data = a;
				a = ea;
				break;
			case MsgProgUnavail:
			case MsgProcUnavail:
			case MsgGarbageArgs:
			case MsgSystemErr:
				rpc->status = SunAcceptError | x;
				break;
			case MsgProgMismatch:
				rpc->status = SunAcceptError | x;
				if(sunUint32Unpack(a, ea, &a, &rpc->low) < 0
				|| sunUint32Unpack(a, ea, &a, &rpc->high) < 0)
					goto Err;
				break;
			}
			break;
		case MsgDenied:
			if(sunUint32Unpack(a, ea, &a, &x) < 0)
				goto Err;
			switch(x){
			default:
				goto Err;
			case MsgAuthError:
				if(sunUint32Unpack(a, ea, &a, &x) < 0)
					goto Err;
				rpc->status = SunAuthError | x;
				break;
			case MsgRpcMismatch:
				rpc->status = SunRejectError | x;
				if(sunUint32Unpack(a, ea, &a, &rpc->low) < 0
				|| sunUint32Unpack(a, ea, &a, &rpc->high) < 0)
					goto Err;
				break;
			}
			break;
		}
	}
	*pa = a;
	return SunSuccess;

Err:
	*pa = ea;
	return SunGarbageArgs;
}

void
sunRpcPrint(Fmt *fmt, SunRpc *rpc)
{
	fmtprint(fmt, "xid=%#ux", rpc->xid);
	if(rpc->iscall){
		fmtprint(fmt, " prog %#ux vers %#ux proc %#ux [", rpc->prog, rpc->vers, rpc->proc);
		sunAuthInfoPrint(fmt, &rpc->cred);
		fmtprint(fmt, "] [");
		sunAuthInfoPrint(fmt, &rpc->verf);
		fmtprint(fmt, "]");
	}else{
		fmtprint(fmt, " status %#ux [", rpc->status);
		sunAuthInfoPrint(fmt, &rpc->verf);
		fmtprint(fmt, "] low %#ux high %#ux", rpc->low, rpc->high);
	}
}

void
sunAuthInfoPrint(Fmt *fmt, SunAuthInfo *ai)
{
	switch(ai->flavor){
	case SunAuthNone:
		fmtprint(fmt, "none");
		break;
	case SunAuthShort:
		fmtprint(fmt, "short");
		break;
	case SunAuthSys:
		fmtprint(fmt, "sys");
		break;
	default:
		fmtprint(fmt, "%#ux", ai->flavor);
		break;
	}
//	if(ai->ndata)
//		fmtprint(fmt, " %.*H", ai->ndata, ai->data);
}

uint
sunAuthInfoSize(SunAuthInfo *ai)
{
	return 4 + sunVarOpaqueSize(ai->ndata);
}

int
sunAuthInfoPack(uchar *a, uchar *ea, uchar **pa, SunAuthInfo *ai)
{
	if(sunUint32Pack(a, ea, &a, &ai->flavor) < 0
	|| sunVarOpaquePack(a, ea, &a, &ai->data, &ai->ndata, 400) < 0)
		goto Err;
	*pa = a;
	return 0;

Err:
	*pa = ea;
	return -1;
}

int
sunAuthInfoUnpack(uchar *a, uchar *ea, uchar **pa, SunAuthInfo *ai)
{
	if(sunUint32Unpack(a, ea, &a, &ai->flavor) < 0
	|| sunVarOpaqueUnpack(a, ea, &a, &ai->data, &ai->ndata, 400) < 0)
		goto Err;
	*pa = a;
	return 0;

Err:
	*pa = ea;
	return -1;
}

int
sunEnumPack(uchar *a, uchar *ea, uchar **pa, int *e)
{
	u32int x;

	x = *e;
	return sunUint32Pack(a, ea, pa, &x);
}

int
sunUint1Pack(uchar *a, uchar *ea, uchar **pa, u1int *u)
{
	u32int x;

	x = *u;
	return sunUint32Pack(a, ea, pa, &x);
}

int
sunUint32Pack(uchar *a, uchar *ea, uchar **pa, u32int *u)
{
	u32int x;

	if(ea-a < 4)
		goto Err;

	x = *u;
	*a++ = x>>24;
	*a++ = x>>16;
	*a++ = x>>8;
	*a++ = x;
	*pa = a;
	return 0;

Err:
	*pa = ea;
	return -1;
}

int
sunEnumUnpack(uchar *a, uchar *ea, uchar **pa, int *e)
{
	u32int x;
	if(sunUint32Unpack(a, ea, pa, &x) < 0)
		return -1;
	*e = x;
	return 0;
}

int
sunUint1Unpack(uchar *a, uchar *ea, uchar **pa, u1int *u)
{
	u32int x;
	if(sunUint32Unpack(a, ea, pa, &x) < 0 || (x!=0 && x!=1)){
		*pa = ea;
		return -1;
	}
	*u = x;
	return 0;
}

int
sunUint32Unpack(uchar *a, uchar *ea, uchar **pa, u32int *u)
{
	u32int x;

	if(ea-a < 4)
		goto Err;
	x = *a++ << 24;
	x |= *a++ << 16;
	x |= *a++ << 8;
	x |= *a++;
	*pa = a;
	*u = x;
	return 0;

Err:
	*pa = ea;
	return -1;
}

int
sunUint64Unpack(uchar *a, uchar *ea, uchar **pa, u64int *u)
{
	u32int x, y;

	if(sunUint32Unpack(a, ea, &a, &x) < 0
	|| sunUint32Unpack(a, ea, &a, &y) < 0)
		goto Err;
	*u = ((uvlong)x<<32) | y;
	*pa = a;
	return 0;
Err:
	*pa = ea;
	return -1;
}

int
sunUint64Pack(uchar *a, uchar *ea, uchar **pa, u64int *u)
{
	u32int x, y;

	x = *u >> 32;
	y = *u;
	if(sunUint32Pack(a, ea, &a, &x) < 0
	|| sunUint32Pack(a, ea, &a, &y) < 0)
		goto Err;
	*pa = a;
	return 0;
Err:
	*pa = ea;
	return -1;
}

uint
sunStringSize(char *s)
{
	return (4+strlen(s)+3) & ~3;
}

int
sunStringUnpack(uchar *a, uchar *ea, uchar **pa, char **s, u32int max)
{
	uchar *dat;
	u32int n;

	if(sunVarOpaqueUnpack(a, ea, pa, &dat, &n, max) < 0)
		goto Err;
	/* slide string down over length to make room for NUL */
	memmove(dat-1, dat, n);
	dat[-1+n] = 0;
	*s = (char*)(dat-1);
	return 0;
Err:
	return -1;
}

int
sunStringPack(uchar *a, uchar *ea, uchar **pa, char **s, u32int max)
{
	u32int n;

	n = strlen(*s);
	return sunVarOpaquePack(a, ea, pa, (uchar**)s, &n, max);
}

uint
sunVarOpaqueSize(u32int n)
{
	return (4+n+3) & ~3;
}

int
sunVarOpaquePack(uchar *a, uchar *ea, uchar **pa, uchar **dat, u32int *ndat, u32int max)
{
	if(*ndat > max || sunUint32Pack(a, ea, &a, ndat) < 0
	|| sunFixedOpaquePack(a, ea, &a, *dat, *ndat) < 0)
		goto Err;
	*pa = a;
	return 0;

Err:
	*pa = ea;
	return -1;
}

int
sunVarOpaqueUnpack(uchar *a, uchar *ea, uchar **pa, uchar **dat, u32int *ndat, u32int max)
{
	if(sunUint32Unpack(a, ea, &a, ndat) < 0
	|| *ndat > max)
		goto Err;
	*dat = a;
	a += (*ndat+3)&~3;
	if(a > ea)
		goto Err;
	*pa = a;
	return 0;

Err:
	*pa = ea;
	return -1;
}

uint
sunFixedOpaqueSize(u32int n)
{
	return (n+3) & ~3;
}

int
sunFixedOpaquePack(uchar *a, uchar *ea, uchar **pa, uchar *dat, u32int n)
{
	uint nn;

	nn = (n+3)&~3;
	if(a+nn > ea)
		goto Err;
	memmove(a, dat, n);
	if(nn > n)
		memset(a+n, 0, nn-n);
	a += nn;
	*pa = a;
	return 0;

Err:
	*pa = ea;
	return -1;
}

int
sunFixedOpaqueUnpack(uchar *a, uchar *ea, uchar **pa, uchar *dat, u32int n)
{
	uint nn;

	nn = (n+3)&~3;
	if(a+nn > ea)
		goto Err;
	memmove(dat, a, n);
	a += nn;
	*pa = a;
	return 0;

Err:
	*pa = ea;
	return -1;
}