portmapper.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 "all.h"

typedef struct Portmap	Portmap;

struct Portmap
{
	int	prog;
	int	vers;
	int	protocol;
	int	port;
};

Portmap map[] = {
	100003, 2, IPPROTO_UDP, 2049,	/* nfs */
//	100003, 3, IPPROTO_UDP, 2049,	/* nfs */
	100005, 1, IPPROTO_UDP, 2049,	/* mount */
	150001, 2, IPPROTO_UDP, 1111,	/* pcnfsd v2 */
	150001, 1, IPPROTO_UDP, 1111,	/* pcnfsd v1 */
	0, 0, 0, 0,
};

static void	pmapinit(int, char**);
static int	pmapnull(int, Rpccall*, Rpccall*);
static int	pmapset(int, Rpccall*, Rpccall*);
static int	pmapunset(int, Rpccall*, Rpccall*);
static int	pmapgetport(int, Rpccall*, Rpccall*);
static int	pmapdump(int, Rpccall*, Rpccall*);
static int	pmapcallit(int, Rpccall*, Rpccall*);

static Procmap pmapproc[] = {
	0, pmapnull,
	1, pmapset,
	2, pmapunset,
	3, pmapgetport,
	4, pmapdump,
	5, pmapcallit,
	0, 0
};

int	myport = 111;

Progmap progmap[] = {
	100000, 2, pmapinit, pmapproc,
	0, 0, 0,
};

void
main(int argc, char *argv[])
{
	server(argc, argv, myport, progmap);
}

static
void
pmapinit(int argc, char **argv)
{
	ARGBEGIN{
	default:
		if(argopt(ARGC()) < 0)
			sysfatal("usage: %s %s", argv0, commonopts);
		break;
	}ARGEND;
	clog("portmapper init\n");
}

static int
pmapnull(int n, Rpccall *cmd, Rpccall *reply)
{
	USED(n, cmd, reply);
	return 0;
}

static int
pmapset(int n, Rpccall *cmd, Rpccall *reply)
{
	uchar *dataptr = reply->results;

	if(n != 16)
		return garbage(reply, "bad count");
	USED(cmd);
	PLONG(FALSE);
	return dataptr - (uchar *)reply->results;
}

static int
pmapunset(int n, Rpccall *cmd, Rpccall *reply)
{
	uchar *dataptr = reply->results;

	if(n != 16)
		return garbage(reply, "bad count");
	USED(cmd);
	PLONG(TRUE);
	return dataptr - (uchar *)reply->results;
}

static int
pmapgetport(int n, Rpccall *cmd, Rpccall *reply)
{
	int prog, vers, prot;
	uchar *argptr = cmd->args;
	uchar *dataptr = reply->results;
	Portmap *mp;

	clog("get port\n");

	if(n != 16)
		return garbage(reply, "bad count");
	prog = GLONG();
	vers = GLONG();
	prot = GLONG();
	chat("host=%I, port=%ld: ", cmd->host, cmd->port);
	chat("getport: %d, %d, %d...", prog, vers, prot);
	for(mp=map; mp->prog>0; mp++)
		if(prog == mp->prog && vers == mp->vers &&
		   prot == mp->protocol)
			break;
	chat("%d\n", mp->port);
	PLONG(mp->port);
	return dataptr - (uchar *)reply->results;
}

static int
pmapdump(int n, Rpccall *cmd, Rpccall *reply)
{
	uchar *dataptr = reply->results;
	Portmap *mp;

	if(n != 0)
		return garbage(reply, "bad count");
	USED(cmd);
	for(mp=map; mp->prog>0; mp++){
		PLONG(1);
		PLONG(mp->prog);
		PLONG(mp->vers);
		PLONG(mp->protocol);
		PLONG(mp->port);
	}
	PLONG(0);
	return dataptr - (uchar *)reply->results;
}

static int
pmapcallit(int n, Rpccall *cmd, Rpccall *reply)
{
	int prog, vers, proc;
	uchar *argptr = cmd->args;
	uchar *dataptr = reply->results;
	Portmap *mp;

	if(n < 12)
		return garbage(reply, "bad count");
	prog = GLONG();
	vers = GLONG();
	proc = GLONG();
	chat("host=%I, port=%ld: ", cmd->host, cmd->port);
	chat("callit: %d, %d, %d...", prog, vers, proc);
	for(mp=map; mp->prog>0; mp++)
		if(prog == mp->prog && vers == mp->vers &&
		   proc == 0)
			break;
	if(mp->port == 0){
		chat("ignored\n");
		return -1;
	}
	chat("%d\n", mp->port);
	PLONG(mp->port);
	PLONG(0);
	return dataptr - (uchar *)reply->results;
}