/* $NetBSD: rpc_fwd.c,v 1.1.1.3 2015/01/17 16:34:15 christos Exp $ */
/*
* Copyright (c) 1997-2014 Erez Zadok
* Copyright (c) 1989 Jan-Simon Pendry
* Copyright (c) 1989 Imperial College of Science, Technology & Medicine
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry at Imperial College, London.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*
* File: am-utils/amd/rpc_fwd.c
*
*/
/*
* RPC packet forwarding
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <am_defs.h>
#include <amd.h>
/*
* Note that the ID field in the external packet is only
* ever treated as a 32 bit opaque data object, so there
* is no need to convert to and from network byte ordering.
*/
#define XID_ALLOC() (xid++)
#define MAX_PACKET_SIZE 8192 /* Maximum UDP packet size */
/*
* Each pending reply has an rpc_forward structure
* associated with it. These have a 15 second lifespan.
* If a new structure is required, then an expired
* one will be re-allocated if available, otherwise a fresh
* one is allocated. Whenever a reply is received the
* structure is discarded.
*/
typedef struct rpc_forward rpc_forward;
struct rpc_forward {
qelem rf_q; /* Linked list */
time_t rf_ttl; /* Time to live */
u_int rf_xid; /* Packet id */
u_int rf_oldid; /* Original packet id */
fwd_fun *rf_fwd; /* Forwarding function */
voidp rf_ptr;
struct sockaddr_in rf_sin;
};
/*
* Head of list of pending replies
*/
qelem rpc_head = {&rpc_head, &rpc_head};
int fwd_sock;
static u_int xid;
/*
* Allocate a rely structure
*/
static rpc_forward *
fwd_alloc(void)
{
time_t now = clocktime(NULL);
rpc_forward *p = NULL, *p2;
/*
* First search for an existing expired one.
*/
ITER(p2, rpc_forward, &rpc_head) {
if (p2->rf_ttl <= now) {
p = p2;
break;
}
}
/*
* If one couldn't be found then allocate
* a new structure and link it at the
* head of the list.
*/
if (p) {
/*
* Call forwarding function to say that
* this message was junked.
*/
dlog("Re-using packet forwarding slot - id %#x", p->rf_xid);
if (p->rf_fwd)
(*p->rf_fwd) (0, 0, 0, &p->rf_sin, p->rf_ptr, FALSE);
rem_que(&p->rf_q);
} else {
p = ALLOC(struct rpc_forward);
}
ins_que(&p->rf_q, &rpc_head);
/*
* Set the time to live field
* Timeout in 43 seconds
*/
p->rf_ttl = now + 43;
return p;
}
/*
* Free an allocated reply structure.
* First unlink it from the list, then
* discard it.
*/
static void
fwd_free(rpc_forward *p)
{
rem_que(&p->rf_q);
XFREE(p);
}
/*
* Initialize the RPC forwarder
*/
int
fwd_init(void)
{
#ifdef FIONBIO
int on = 1;
#endif /* FIONBIO */
#ifdef HAVE_TRANSPORT_TYPE_TLI
/*
* Create ping TLI socket (/dev/tcp and /dev/ticlts did not work)
* (HPUX-11 does not like using O_NDELAY in flags)
*/
fwd_sock = t_open("/dev/udp", O_RDWR|O_NONBLOCK, 0);
if (fwd_sock < 0) {
plog(XLOG_ERROR, "unable to create RPC forwarding TLI socket: %s",
t_errlist[t_errno]);
return errno;
}
#else /* not HAVE_TRANSPORT_TYPE_TLI */
/*
* Create ping socket
*/
fwd_sock = socket(AF_INET, SOCK_DGRAM, 0);
if (fwd_sock < 0) {
plog(XLOG_ERROR, "unable to create RPC forwarding socket: %m");
return errno;
}
#endif /* not HAVE_TRANSPORT_TYPE_TLI */
/*
* Some things we talk to require a priv port - so make one here
*/
if (bind_resv_port(fwd_sock, (u_short *) NULL) < 0)
plog(XLOG_ERROR, "can't bind privileged port (rpc_fwd)");
if (fcntl(fwd_sock, F_SETFL, FNDELAY) < 0
#ifdef FIONBIO
&& ioctl(fwd_sock, FIONBIO, &on) < 0
#endif /* FIONBIO */
) {
plog(XLOG_ERROR, "Can't set non-block on forwarding socket: %m");
return errno;
}
return 0;
}
/*
* Locate a packet in the forwarding list
*/
static rpc_forward *
fwd_locate(u_int id)
{
rpc_forward *p;
ITER(p, rpc_forward, &rpc_head) {
if (p->rf_xid == id)
return p;
}
return 0;
}
/*
* This is called to forward a packet to another
* RPC server. The message id is changed and noted
* so that when a reply appears we can tie it up
* correctly. Just matching the reply's source address
* would not work because it might come from a
* different address.
*/
int
fwd_packet(int type_id, char *pkt, int len, struct sockaddr_in *fwdto, struct sockaddr_in *replyto, opaque_t cb_arg, fwd_fun cb)
{
rpc_forward *p;
u_int *pkt_int;
int error;
#ifdef HAVE_TRANSPORT_TYPE_TLI
struct t_unitdata ud;
#endif /* HAVE_TRANSPORT_TYPE_TLI */
if ((int) amd_state >= (int) Finishing)
return ENOENT;
/*
* See if the type_id is fully specified.
* If so, then discard any old entries
* for this id.
* Otherwise make sure the type_id is
* fully qualified by allocating an id here.
*/
switch (type_id & RPC_XID_MASK) {
case RPC_XID_PORTMAP:
dlog("Sending PORTMAP request %#x", type_id);
break;
case RPC_XID_MOUNTD:
dlog("Sending MOUNTD request %#x", type_id);
break;
case RPC_XID_NFSPING:
dlog("Sending NFS ping %#x", type_id);
break;
case RPC_XID_WEBNFS:
dlog("Sending WebNFS lookup %#x", type_id);
break;
default:
dlog("UNKNOWN RPC XID %#x", type_id);
break;
}
if (type_id & ~RPC_XID_MASK) {
p = fwd_locate(type_id);
if (p) {
dlog("Discarding earlier rpc fwd handle");
fwd_free(p);
}
} else {
dlog("Allocating a new xid...");
type_id = MK_RPC_XID(type_id, XID_ALLOC());
}
p = fwd_alloc();
if (!p)
return ENOBUFS;
error = 0;
pkt_int = (u_int *) pkt;
/*
* Get the original packet id
*/
p->rf_oldid = ntohl(*pkt_int);
/*
* Replace with newly allocated id
*/
p->rf_xid = type_id;
*pkt_int = htonl(type_id);
/*
* The sendto may fail if, for example, the route
* to a remote host is lost because an intermediate
* gateway has gone down. Important to fill in the
* rest of "p" otherwise nasty things happen later...
*/
#ifdef DEBUG
{
char dq[20];
if (p && fwdto)
dlog("Sending packet id %#x to %s:%d",
p->rf_xid,
inet_dquad(dq, sizeof(dq), fwdto->sin_addr.s_addr),
ntohs(fwdto->sin_port));
}
#endif /* DEBUG */
/* if NULL, remote server probably down */
if (!fwdto) {
error = AM_ERRNO_HOST_DOWN;
goto out;
}
#ifdef HAVE_TRANSPORT_TYPE_TLI
ud.addr.buf = (char *) fwdto;
if (fwdto) /* if NULL, set sizes to zero */
ud.addr.maxlen = ud.addr.len = sizeof(struct sockaddr_in);
else
ud.addr.maxlen = ud.addr.len = 0;
ud.opt.buf = (char *) NULL;
ud.opt.maxlen = ud.opt.len = 0;
ud.udata.buf = pkt;
ud.udata.maxlen = ud.udata.len = len;
if (t_sndudata(fwd_sock, &ud) < 0) {
plog(XLOG_ERROR,"fwd_packet failed: t_errno=%d, errno=%d",t_errno,errno);
error = errno;
}
#else /* not HAVE_TRANSPORT_TYPE_TLI */
if (sendto(fwd_sock, (char *) pkt, len, 0,
(struct sockaddr *) fwdto, sizeof(*fwdto)) < 0)
error = errno;
#endif /* not HAVE_TRANSPORT_TYPE_TLI */
/*
* Save callback function and return address
*/
out:
p->rf_fwd = cb;
if (replyto)
p->rf_sin = *replyto;
else
memset((voidp) &p->rf_sin, 0, sizeof(p->rf_sin));
p->rf_ptr = cb_arg;
return error;
}
/*
* Called when some data arrives on the forwarding socket
*/
void
fwd_reply(void)
{
int len;
u_int pkt[MAX_PACKET_SIZE / sizeof(u_int) + 1];
u_int *pkt_int;
u_int pkt_xid;
int rc;
rpc_forward *p;
struct sockaddr_in src_addr;
RECVFROM_FROMLEN_TYPE src_addr_len;
#ifdef HAVE_TRANSPORT_TYPE_TLI
struct t_unitdata ud;
int flags = 0;
#endif /* HAVE_TRANSPORT_TYPE_TLI */
/*
* Determine the length of the packet
*/
len = MAX_PACKET_SIZE;
/*
* Read the packet and check for validity
*/
again:
src_addr_len = sizeof(src_addr);
#ifdef HAVE_TRANSPORT_TYPE_TLI
ud.addr.buf = (char *) &src_addr;
ud.addr.maxlen = ud.addr.len = src_addr_len;
ud.opt.buf = (char *) NULL;
ud.opt.maxlen = ud.opt.len = 0;
ud.udata.buf = (char *) pkt;
ud.udata.maxlen = ud.udata.len = len;
/* XXX: use flags accordingly such as if T_MORE set */
rc = t_rcvudata(fwd_sock, &ud, &flags);
if (rc == 0) /* success, reset rc to length */
rc = ud.udata.len;
else {
plog(XLOG_ERROR,"fwd_reply failed: t_errno=%d, errno=%d, flags=%d",t_errno,errno, flags);
/*
* Clear error indication, otherwise the error condition persists and
* amd gets into an infinite loop.
*/
if (t_errno == TLOOK)
t_rcvuderr(fwd_sock, NULL);
}
#else /* not HAVE_TRANSPORT_TYPE_TLI */
rc = recvfrom(fwd_sock,
(char *) pkt,
len,
0,
(struct sockaddr *) &src_addr,
&src_addr_len);
#endif /* not HAVE_TRANSPORT_TYPE_TLI */
/*
* XXX: in svr4, if the T_MORE bit of flags is set, what do
* we then do? -Erez
*/
if (rc < 0 || src_addr_len != sizeof(src_addr) ||
src_addr.sin_family != AF_INET) {
if (rc < 0 && errno == EINTR)
goto again;
plog(XLOG_ERROR, "Error reading RPC reply: %m");
goto out;
}
/*
* Do no more work if finishing soon
*/
if ((int) amd_state >= (int) Finishing)
goto out;
/*
* Find packet reference
*/
pkt_int = (u_int *) pkt;
pkt_xid = ntohl(*pkt_int);
switch (pkt_xid & RPC_XID_MASK) {
case RPC_XID_PORTMAP:
dlog("Receiving PORTMAP reply %#x", pkt_xid);
break;
case RPC_XID_MOUNTD:
dlog("Receiving MOUNTD reply %#x", pkt_xid);
break;
case RPC_XID_NFSPING:
dlog("Receiving NFS ping %#x", pkt_xid);
break;
case RPC_XID_WEBNFS:
dlog("Receiving WebNFS lookup %#x", pkt_xid);
break;
default:
dlog("UNKNOWN RPC XID %#x", pkt_xid);
break;
}
p = fwd_locate(pkt_xid);
if (!p) {
dlog("Can't forward reply id %#x", pkt_xid);
goto out;
}
if (p->rf_fwd) {
/*
* Put the original message id back
* into the packet.
*/
*pkt_int = htonl(p->rf_oldid);
/*
* Call forwarding function
*/
(*p->rf_fwd) ((voidp) pkt, rc, &src_addr, &p->rf_sin, p->rf_ptr, TRUE);
}
/*
* Free forwarding info
*/
fwd_free(p);
out:;
}
