/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
/*	  All Rights Reserved  	*/

/*	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T	*/
/*	The copyright notice above does not evidence any   	*/
/*	actual or intended publication of such source code.	*/

#ident	"@(#)svc_udp.c	1.7	98/08/10 SMI"	/* SVr4.0 1.1	*/

/*
******************************************************************

		PROPRIETARY NOTICE(Combined)

This source code is unpublished proprietary information
constituting, or derived under license from AT&T's UNIX(r) System V.
In addition, portions of such source code were derived from Berkeley
4.3 BSD under license from the Regents of the University of
California.



		Copyright Notice

Notice of copyright on this source code product does not indicate
publication.

	(c) 1986, 1987, 1988, 1989, 1990  Sun Microsystems, Inc
	(c) 1983, 1984, 1985, 1986, 1987, 1988, 1989  AT&T.
			All rights reserved.
********************************************************************
*/

#if !defined(lint) && defined(SCCSIDS)
static char sccsid[] = "@(#)svc_udp.c 1.26 88/06/11 Copyr 1984 Sun Micro";
#endif

/*
 * svc_udp.c,
 * Server side for UDP/IP based RPC.  (Does some caching in the hopes of
 * achieving execute-at-most-once semantics.)
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 */

#include <rpc/rpc.h>
#include <sys/socket.h>
#include <errno.h>
#include <syslog.h>
#include <malloc.h>
#include <stdio.h>


#define	rpc_buffer(xprt) ((xprt)->xp_p1)

static struct xp_ops *svcudp_ops();

extern int errno;
extern SVCXPRT *svc_xprt_alloc();
extern void svc_xprt_free();
extern int _socket(int, int, int);
extern int _bind(int, const struct sockaddr *, int);
extern int _getsockname(int, struct sockaddr *, int *);
extern int _listen(int, int);
extern int _accept(int, struct sockaddr *, int *);
extern int bindresvport(int, struct sockaddr_in *);
extern int _recvfrom(int, char *, int, int,
		struct sockaddr *, int *);
extern int _sendto(int, const char *, int, int,
		const struct sockaddr *, int);

static int cache_get(SVCXPRT *, struct rpc_msg *,
		char **, uint_t *);
static void cache_set(SVCXPRT *, uint_t);

/*
 * kept in xprt->xp_p2
 */
struct svcudp_data {
	u_int   su_iosz;		/* byte size of send.recv buffer */
	uint32_t su_xid;		/* transaction id */
	XDR	su_xdrs;		/* XDR handle */
	char	su_verfbody[MAX_AUTH_BYTES];	/* verifier body */
	char * 	su_cache;	/* cached data, NULL if no cache */
};
#define	su_data(xprt)	((struct svcudp_data *)(xprt->xp_p2))

/*
 * Usage:
 *	xprt = svcudp_create(sock);
 *
 * If sock<0 then a socket is created, else sock is used.
 * If the socket, sock is not bound to a port then svcudp_create
 * binds it to an arbitrary port.  In any (successful) case,
 * xprt->xp_sock is the registered socket number and xprt->xp_port is the
 * associated port number.
 * Once *xprt is initialized, it is registered as a transporter;
 * see (svc.h, xprt_register).
 * The routines returns NULL if a problem occurred.
 */
SVCXPRT *
svcudp_bufcreate(sock, sendsz, recvsz)
	register int sock;
	u_int sendsz, recvsz;
{
	bool_t madesock = FALSE;
	register SVCXPRT *xprt;
	register struct svcudp_data *su;
	struct sockaddr_in addr;
	int len = sizeof (struct sockaddr_in);

	if (sock == RPC_ANYSOCK) {
		if ((sock = _socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
			(void) syslog(LOG_ERR, "svcudp_create: socket",
				" creation problem: %m");
			return ((SVCXPRT *)NULL);
		}
		madesock = TRUE;
	}
	memset((char *)&addr, 0, sizeof (addr));
	addr.sin_family = AF_INET;
	if (bindresvport(sock, &addr)) {
		addr.sin_port = 0;
		(void) _bind(sock, (struct sockaddr *)&addr, len);
	}
	if (_getsockname(sock, (struct sockaddr *)&addr, &len) != 0) {
		(void) syslog(LOG_ERR, "svcudp_create -",
			" cannot getsockname: %m");
		if (madesock)
			(void) close(sock);
		return ((SVCXPRT *)NULL);
	}
	xprt = svc_xprt_alloc();
	if (xprt == NULL) {
		(void) syslog(LOG_ERR, "svcudp_create: out of memory");
		if (madesock)
			(void) close(sock);
		return ((SVCXPRT *)NULL);
	}
	su = (struct svcudp_data *)mem_alloc(sizeof (*su));
	if (su == NULL) {
		(void) syslog(LOG_ERR, "svcudp_create: out of memory");
		svc_xprt_free(xprt);
		if (madesock)
			(void) close(sock);
		return ((SVCXPRT *)NULL);
	}
	su->su_iosz = ((MAX(sendsz, recvsz) + 3) / 4) * 4;
	if ((rpc_buffer(xprt) = (char *)mem_alloc(su->su_iosz)) == NULL) {
		(void) syslog(LOG_ERR, "svcudp_create: out of memory");
		mem_free((char *) su, sizeof (*su));
		svc_xprt_free(xprt);
		if (madesock)
			(void) close(sock);
		return ((SVCXPRT *)NULL);
	}
	xdrmem_create(
	    &(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_DECODE);
	su->su_cache = NULL;
	xprt->xp_p2 = (caddr_t)su;
	xprt->xp_netid = NULL;
	xprt->xp_verf.oa_base = su->su_verfbody;
	xprt->xp_ops = svcudp_ops();
	xprt->xp_port = ntohs(addr.sin_port);
	xprt->xp_sock = sock;
	xprt->xp_rtaddr.buf = &xprt->xp_raddr[0];
	xprt_register(xprt);
	return (xprt);
}

SVCXPRT *
svcudp_create(sock)
	int sock;
{

	return (svcudp_bufcreate(sock, UDPMSGSIZE, UDPMSGSIZE));
}

static enum xprt_stat
svcudp_stat(xprt)
	SVCXPRT *xprt;
{

	return (XPRT_IDLE);
}

static bool_t
svcudp_recv(xprt, msg)
	register SVCXPRT *xprt;
	struct rpc_msg *msg;
{
	register struct svcudp_data *su = su_data(xprt);
	register XDR *xdrs = &(su->su_xdrs);
	register int rlen;
	char *reply;
	uint_t replylen;

	again:
	xprt->xp_addrlen = sizeof (struct sockaddr_in);
	rlen = _recvfrom(xprt->xp_sock, rpc_buffer(xprt), (int) su->su_iosz,
	    0, (struct sockaddr *)&(xprt->xp_raddr), &(xprt->xp_addrlen));
	if (rlen == -1 && errno == EINTR)
		goto again;
	if (rlen < 4*sizeof (uint32_t))
		return (FALSE);
	xdrs->x_op = XDR_DECODE;
	XDR_SETPOS(xdrs, 0);
	if (! xdr_callmsg(xdrs, msg))
		return (FALSE);
	su->su_xid = msg->rm_xid;
	if (su->su_cache != NULL) {
		if (cache_get(xprt, msg, &reply, &replylen)) {
			(void) _sendto(xprt->xp_sock, reply, (int) replylen, 0,
				(struct sockaddr *) &xprt->xp_raddr,
				xprt->xp_addrlen);
			return (TRUE);
		}
	}
	return (TRUE);
}

static bool_t
svcudp_reply(xprt, msg)
	register SVCXPRT *xprt;
	struct rpc_msg *msg;
{
	register struct svcudp_data *su = su_data(xprt);
	register XDR *xdrs = &(su->su_xdrs);
	register int slen;
	register bool_t stat = FALSE;

	xdrs->x_op = XDR_ENCODE;
	XDR_SETPOS(xdrs, 0);
	msg->rm_xid = su->su_xid;
	if (xdr_replymsg(xdrs, msg)) {
		slen = (int)XDR_GETPOS(xdrs);
		if (_sendto(xprt->xp_sock, rpc_buffer(xprt), slen, 0,
		    (struct sockaddr *)&(xprt->xp_raddr), xprt->xp_addrlen)
		    == slen) {
			stat = TRUE;
			if (su->su_cache && slen >= 0) {
				(void) cache_set(xprt, (uint_t) slen);
			}
		}
	}
	return (stat);
}

static bool_t
svcudp_getargs(xprt, xdr_args, args_ptr)
	SVCXPRT *xprt;
	xdrproc_t xdr_args;
	caddr_t args_ptr;
{

	return ((*xdr_args)(&(su_data(xprt)->su_xdrs), args_ptr));
}

static bool_t
svcudp_freeargs(xprt, xdr_args, args_ptr)
	SVCXPRT *xprt;
	xdrproc_t xdr_args;
	caddr_t args_ptr;
{
	register XDR *xdrs = &(su_data(xprt)->su_xdrs);

	xdrs->x_op = XDR_FREE;
	return ((*xdr_args)(xdrs, args_ptr));
}

static void
svcudp_destroy(xprt)
	register SVCXPRT *xprt;
{
	register struct svcudp_data *su = su_data(xprt);

	xprt_unregister(xprt);
	(void) close(xprt->xp_sock);
	XDR_DESTROY(&(su->su_xdrs));
	mem_free(rpc_buffer(xprt), su->su_iosz);
	mem_free((caddr_t)su, sizeof (struct svcudp_data));
	svc_xprt_free(xprt);
}


/* **********this could be a separate file********************* */

/*
 * Fifo cache for udp server
 * Copies pointers to reply buffers into fifo cache
 * Buffers are sent again if retransmissions are detected.
 */

#define	SPARSENESS 4	/* 75% sparse */

#define	ALLOC(type, size)	\
	(type *) mem_alloc((unsigned) (sizeof (type) * (size)))

#define	BZERO(addr, type, size)	 \
	memset((char *) (addr), 0, sizeof (type) * (int) (size))

#define	FREE(addr, type, size)	\
	(void) mem_free((char *) (addr), (sizeof (type) * (size)))

/*
 * An entry in the cache
 */
typedef struct cache_node *cache_ptr;
struct cache_node {
	/*
	 * Index into cache is xid, proc, vers, prog and address
	 */
	uint32_t cache_xid;
	uint32_t cache_proc;
	uint32_t cache_vers;
	uint32_t cache_prog;
	struct sockaddr_in cache_addr;
	/*
	 * The cached reply and length
	 */
	char * cache_reply;
	uint32_t cache_replylen;
	/*
	 * Next node on the list, if there is a collision
	 */
	cache_ptr cache_next;
};



/*
 * The entire cache
 */
struct udp_cache {
	uint32_t uc_size;		/* size of cache */
	cache_ptr *uc_entries;	/* hash table of entries in cache */
	cache_ptr *uc_fifo;	/* fifo list of entries in cache */
	uint32_t uc_nextvictim;	/* points to next victim in fifo list */
	uint32_t uc_prog;		/* saved program number */
	uint32_t uc_vers;		/* saved version number */
	uint32_t uc_proc;		/* saved procedure number */
	struct sockaddr_in uc_addr; /* saved caller's address */
};


/*
 * the hashing function
 */
#define	CACHE_LOC(transp, xid)	\
	(xid % (SPARSENESS*((struct udp_cache *) \
	su_data(transp)->su_cache)->uc_size))


/*
 * Enable use of the cache.
 * Note: there is no disable.
 */
svcudp_enablecache(transp, size)
	SVCXPRT *transp;
	uint_t size;
{
	struct svcudp_data *su = su_data(transp);
	struct udp_cache *uc;

	if (su->su_cache != NULL) {
		(void) syslog(LOG_ERR, "enablecache: cache already enabled");
		return (0);
	}
	uc = ALLOC(struct udp_cache, 1);
	if (uc == NULL) {
		(void) syslog(LOG_ERR, "enablecache: could not allocate cache");
		return (0);
	}
	uc->uc_size = size;
	uc->uc_nextvictim = 0;
	uc->uc_entries = ALLOC(cache_ptr, size * SPARSENESS);
	if (uc->uc_entries == NULL) {
		(void) syslog(LOG_ERR, "enablecache: could not",
			" allocate cache data");
		FREE(uc, struct udp_cache, 1);
		return (0);
	}
	BZERO(uc->uc_entries, cache_ptr, size * SPARSENESS);
	uc->uc_fifo = ALLOC(cache_ptr, size);
	if (uc->uc_fifo == NULL) {
		(void) syslog(LOG_ERR, "enablecache: could not",
			" allocate cache fifo");
		FREE((char *)uc->uc_entries, cache_ptr, size * SPARSENESS);
		FREE((char *)uc, struct udp_cache, 1);
		return (0);
	}
	BZERO(uc->uc_fifo, cache_ptr, size);
	su->su_cache = (char *) uc;
	return (1);
}


/*
 * Set an entry in the cache
 */
static void
cache_set(xprt, replylen)
	SVCXPRT *xprt;
	uint_t replylen;
{
	register cache_ptr victim;
	register cache_ptr *vicp;
	register struct svcudp_data *su = su_data(xprt);
	struct udp_cache *uc = (struct udp_cache *) su->su_cache;
	u_int loc;
	char *newbuf;

	/*
	 * Find space for the new entry, either by
	 * reusing an old entry, or by mallocing a new one
	 */
	victim = uc->uc_fifo[uc->uc_nextvictim];
	if (victim != NULL) {
		loc = CACHE_LOC(xprt, victim->cache_xid);
		for (vicp = &uc->uc_entries[loc];
			*vicp != NULL && *vicp != victim;
			vicp = &(*vicp)->cache_next)
				;
		if (*vicp == NULL) {
			(void) syslog(LOG_ERR, "cache_set: victim not found");
			return;
		}
		*vicp = victim->cache_next;	/* remote from cache */
		newbuf = victim->cache_reply;
	} else {
		victim = ALLOC(struct cache_node, 1);
		if (victim == NULL) {
			(void) syslog(LOG_ERR, "cache_set: victim alloc",
				" failed");
			return;
		}
		newbuf = (char *)mem_alloc(su->su_iosz);
		if (newbuf == NULL) {
			(void) syslog(LOG_ERR, "cache_set: could not",
				" allocate new rpc_buffer");
			FREE(victim, struct cache_node, 1);
			return;
		}
	}

	/*
	 * Store it away
	 */
	victim->cache_replylen = replylen;
	victim->cache_reply = rpc_buffer(xprt);
	rpc_buffer(xprt) = newbuf;
	xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt),
		su->su_iosz, XDR_ENCODE);
	victim->cache_xid = su->su_xid;
	victim->cache_proc = uc->uc_proc;
	victim->cache_vers = uc->uc_vers;
	victim->cache_prog = uc->uc_prog;
	victim->cache_addr = uc->uc_addr;
	loc = CACHE_LOC(xprt, victim->cache_xid);
	victim->cache_next = uc->uc_entries[loc];
	uc->uc_entries[loc] = victim;
	uc->uc_fifo[uc->uc_nextvictim++] = victim;
	uc->uc_nextvictim %= uc->uc_size;
}

/*
 * Try to get an entry from the cache
 * return 1 if found, 0 if not found
 */
static int
cache_get(xprt, msg, replyp, replylenp)
	SVCXPRT *xprt;
	struct rpc_msg *msg;
	char **replyp;
	uint_t *replylenp;
{
	u_int loc;
	register cache_ptr ent;
	register struct svcudp_data *su = su_data(xprt);
	register struct udp_cache *uc = (struct udp_cache *) su->su_cache;

#define	EQADDR(a1, a2) \
	(memcmp((char *)&a1, (char *)&a2, sizeof (a1)) == 0)

	loc = CACHE_LOC(xprt, su->su_xid);
	for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next) {
		if (ent->cache_xid == su->su_xid &&
			ent->cache_proc == uc->uc_proc &&
			ent->cache_vers == uc->uc_vers &&
			ent->cache_prog == uc->uc_prog &&
			EQADDR(ent->cache_addr, uc->uc_addr)) {
			*replyp = ent->cache_reply;
			*replylenp = ent->cache_replylen;
			return (1);
		}
	}
	/*
	 * Failed to find entry
	 * Remember a few things so we can do a set later
	 */
	uc->uc_proc = msg->rm_call.cb_proc;
	uc->uc_vers = msg->rm_call.cb_vers;
	uc->uc_prog = msg->rm_call.cb_prog;
	memcpy((char *)&uc->uc_addr, (char *)&xprt->xp_raddr,
		sizeof (struct sockaddr_in));
	return (0);
}

static struct xp_ops *
svcudp_ops()
{
	static struct xp_ops ops;

	if (ops.xp_recv == NULL) {
		ops.xp_recv = svcudp_recv;
		ops.xp_stat = svcudp_stat;
		ops.xp_getargs = svcudp_getargs;
		ops.xp_reply = svcudp_reply;
		ops.xp_freeargs = svcudp_freeargs;
		ops.xp_destroy = svcudp_destroy;
	}
	return (&ops);
}
