xref: /netbsd-src/external/bsd/am-utils/dist/amd/rpc_fwd.c (revision 8bae5d409deb915cf7c8f0539fae22ff2cb8a313)
1 /*	$NetBSD: rpc_fwd.c,v 1.1.1.3 2015/01/17 16:34:15 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1997-2014 Erez Zadok
5  * Copyright (c) 1989 Jan-Simon Pendry
6  * Copyright (c) 1989 Imperial College of Science, Technology & Medicine
7  * Copyright (c) 1989 The Regents of the University of California.
8  * All rights reserved.
9  *
10  * This code is derived from software contributed to Berkeley by
11  * Jan-Simon Pendry at Imperial College, London.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  *
37  *
38  * File: am-utils/amd/rpc_fwd.c
39  *
40  */
41 
42 /*
43  * RPC packet forwarding
44  */
45 
46 #ifdef HAVE_CONFIG_H
47 # include <config.h>
48 #endif /* HAVE_CONFIG_H */
49 #include <am_defs.h>
50 #include <amd.h>
51 
52 /*
53  * Note that the ID field in the external packet is only
54  * ever treated as a 32 bit opaque data object, so there
55  * is no need to convert to and from network byte ordering.
56  */
57 
58 #define	XID_ALLOC()		(xid++)
59 #define	MAX_PACKET_SIZE	8192	/* Maximum UDP packet size */
60 
61 /*
62  * Each pending reply has an rpc_forward structure
63  * associated with it.  These have a 15 second lifespan.
64  * If a new structure is required, then an expired
65  * one will be re-allocated if available, otherwise a fresh
66  * one is allocated.  Whenever a reply is received the
67  * structure is discarded.
68  */
69 typedef struct rpc_forward rpc_forward;
70 struct rpc_forward {
71   qelem rf_q;			/* Linked list */
72   time_t rf_ttl;		/* Time to live */
73   u_int rf_xid;			/* Packet id */
74   u_int rf_oldid;		/* Original packet id */
75   fwd_fun *rf_fwd;		/* Forwarding function */
76   voidp rf_ptr;
77   struct sockaddr_in rf_sin;
78 };
79 
80 /*
81  * Head of list of pending replies
82  */
83 qelem rpc_head = {&rpc_head, &rpc_head};
84 int fwd_sock;
85 static u_int xid;
86 
87 
88 /*
89  * Allocate a rely structure
90  */
91 static rpc_forward *
fwd_alloc(void)92 fwd_alloc(void)
93 {
94   time_t now = clocktime(NULL);
95   rpc_forward *p = NULL, *p2;
96 
97   /*
98    * First search for an existing expired one.
99    */
100   ITER(p2, rpc_forward, &rpc_head) {
101     if (p2->rf_ttl <= now) {
102       p = p2;
103       break;
104     }
105   }
106 
107   /*
108    * If one couldn't be found then allocate
109    * a new structure and link it at the
110    * head of the list.
111    */
112   if (p) {
113     /*
114      * Call forwarding function to say that
115      * this message was junked.
116      */
117     dlog("Re-using packet forwarding slot - id %#x", p->rf_xid);
118     if (p->rf_fwd)
119       (*p->rf_fwd) (0, 0, 0, &p->rf_sin, p->rf_ptr, FALSE);
120     rem_que(&p->rf_q);
121   } else {
122     p = ALLOC(struct rpc_forward);
123   }
124   ins_que(&p->rf_q, &rpc_head);
125 
126   /*
127    * Set the time to live field
128    * Timeout in 43 seconds
129    */
130   p->rf_ttl = now + 43;
131 
132   return p;
133 }
134 
135 
136 /*
137  * Free an allocated reply structure.
138  * First unlink it from the list, then
139  * discard it.
140  */
141 static void
fwd_free(rpc_forward * p)142 fwd_free(rpc_forward *p)
143 {
144   rem_que(&p->rf_q);
145   XFREE(p);
146 }
147 
148 
149 /*
150  * Initialize the RPC forwarder
151  */
152 int
fwd_init(void)153 fwd_init(void)
154 {
155 #ifdef FIONBIO
156   int on = 1;
157 #endif /* FIONBIO */
158 
159 #ifdef HAVE_TRANSPORT_TYPE_TLI
160   /*
161    * Create ping TLI socket (/dev/tcp and /dev/ticlts did not work)
162    * (HPUX-11 does not like using O_NDELAY in flags)
163    */
164   fwd_sock = t_open("/dev/udp", O_RDWR|O_NONBLOCK, 0);
165   if (fwd_sock < 0) {
166     plog(XLOG_ERROR, "unable to create RPC forwarding TLI socket: %s",
167 	 t_errlist[t_errno]);
168     return errno;
169   }
170 #else /* not HAVE_TRANSPORT_TYPE_TLI */
171   /*
172    * Create ping socket
173    */
174   fwd_sock = socket(AF_INET, SOCK_DGRAM, 0);
175   if (fwd_sock < 0) {
176     plog(XLOG_ERROR, "unable to create RPC forwarding socket: %m");
177     return errno;
178   }
179 #endif /* not HAVE_TRANSPORT_TYPE_TLI */
180 
181   /*
182    * Some things we talk to require a priv port - so make one here
183    */
184   if (bind_resv_port(fwd_sock, (u_short *) NULL) < 0)
185     plog(XLOG_ERROR, "can't bind privileged port (rpc_fwd)");
186 
187   if (fcntl(fwd_sock, F_SETFL, FNDELAY) < 0
188 #ifdef FIONBIO
189       && ioctl(fwd_sock, FIONBIO, &on) < 0
190 #endif /* FIONBIO */
191     ) {
192     plog(XLOG_ERROR, "Can't set non-block on forwarding socket: %m");
193     return errno;
194   }
195 
196   return 0;
197 }
198 
199 
200 /*
201  * Locate a packet in the forwarding list
202  */
203 static rpc_forward *
fwd_locate(u_int id)204 fwd_locate(u_int id)
205 {
206   rpc_forward *p;
207 
208   ITER(p, rpc_forward, &rpc_head) {
209     if (p->rf_xid == id)
210       return p;
211   }
212 
213   return 0;
214 }
215 
216 
217 /*
218  * This is called to forward a packet to another
219  * RPC server.  The message id is changed and noted
220  * so that when a reply appears we can tie it up
221  * correctly.  Just matching the reply's source address
222  * would not work because it might come from a
223  * different address.
224  */
225 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)226 fwd_packet(int type_id, char *pkt, int len, struct sockaddr_in *fwdto, struct sockaddr_in *replyto, opaque_t cb_arg, fwd_fun cb)
227 {
228   rpc_forward *p;
229   u_int *pkt_int;
230   int error;
231 #ifdef HAVE_TRANSPORT_TYPE_TLI
232   struct t_unitdata ud;
233 #endif /* HAVE_TRANSPORT_TYPE_TLI */
234 
235   if ((int) amd_state >= (int) Finishing)
236     return ENOENT;
237 
238   /*
239    * See if the type_id is fully specified.
240    * If so, then discard any old entries
241    * for this id.
242    * Otherwise make sure the type_id is
243    * fully qualified by allocating an id here.
244    */
245   switch (type_id & RPC_XID_MASK) {
246   case RPC_XID_PORTMAP:
247     dlog("Sending PORTMAP request %#x", type_id);
248     break;
249   case RPC_XID_MOUNTD:
250     dlog("Sending MOUNTD request %#x", type_id);
251     break;
252   case RPC_XID_NFSPING:
253     dlog("Sending NFS ping %#x", type_id);
254     break;
255   case RPC_XID_WEBNFS:
256     dlog("Sending WebNFS lookup %#x", type_id);
257     break;
258   default:
259     dlog("UNKNOWN RPC XID %#x", type_id);
260     break;
261   }
262 
263   if (type_id & ~RPC_XID_MASK) {
264     p = fwd_locate(type_id);
265     if (p) {
266       dlog("Discarding earlier rpc fwd handle");
267       fwd_free(p);
268     }
269   } else {
270     dlog("Allocating a new xid...");
271     type_id = MK_RPC_XID(type_id, XID_ALLOC());
272   }
273 
274   p = fwd_alloc();
275   if (!p)
276     return ENOBUFS;
277 
278   error = 0;
279 
280   pkt_int = (u_int *) pkt;
281 
282   /*
283    * Get the original packet id
284    */
285   p->rf_oldid = ntohl(*pkt_int);
286 
287   /*
288    * Replace with newly allocated id
289    */
290   p->rf_xid = type_id;
291   *pkt_int = htonl(type_id);
292 
293   /*
294    * The sendto may fail if, for example, the route
295    * to a remote host is lost because an intermediate
296    * gateway has gone down.  Important to fill in the
297    * rest of "p" otherwise nasty things happen later...
298    */
299 #ifdef DEBUG
300   {
301     char dq[20];
302     if (p && fwdto)
303       dlog("Sending packet id %#x to %s:%d",
304 	   p->rf_xid,
305 	   inet_dquad(dq, sizeof(dq), fwdto->sin_addr.s_addr),
306 	   ntohs(fwdto->sin_port));
307   }
308 #endif /* DEBUG */
309 
310   /* if NULL, remote server probably down */
311   if (!fwdto) {
312     error = AM_ERRNO_HOST_DOWN;
313     goto out;
314   }
315 
316 #ifdef HAVE_TRANSPORT_TYPE_TLI
317   ud.addr.buf = (char *) fwdto;
318   if (fwdto)			/* if NULL, set sizes to zero */
319     ud.addr.maxlen = ud.addr.len = sizeof(struct sockaddr_in);
320   else
321     ud.addr.maxlen = ud.addr.len = 0;
322   ud.opt.buf = (char *) NULL;
323   ud.opt.maxlen = ud.opt.len = 0;
324   ud.udata.buf = pkt;
325   ud.udata.maxlen = ud.udata.len = len;
326   if (t_sndudata(fwd_sock, &ud) < 0) {
327     plog(XLOG_ERROR,"fwd_packet failed: t_errno=%d, errno=%d",t_errno,errno);
328     error = errno;
329   }
330 #else /* not HAVE_TRANSPORT_TYPE_TLI */
331   if (sendto(fwd_sock, (char *) pkt, len, 0,
332 	     (struct sockaddr *) fwdto, sizeof(*fwdto)) < 0)
333     error = errno;
334 #endif /* not HAVE_TRANSPORT_TYPE_TLI */
335 
336   /*
337    * Save callback function and return address
338    */
339 out:
340   p->rf_fwd = cb;
341   if (replyto)
342     p->rf_sin = *replyto;
343   else
344     memset((voidp) &p->rf_sin, 0, sizeof(p->rf_sin));
345   p->rf_ptr = cb_arg;
346 
347   return error;
348 }
349 
350 
351 /*
352  * Called when some data arrives on the forwarding socket
353  */
354 void
fwd_reply(void)355 fwd_reply(void)
356 {
357   int len;
358   u_int pkt[MAX_PACKET_SIZE / sizeof(u_int) + 1];
359   u_int *pkt_int;
360   u_int pkt_xid;
361   int rc;
362   rpc_forward *p;
363   struct sockaddr_in src_addr;
364   RECVFROM_FROMLEN_TYPE src_addr_len;
365 #ifdef HAVE_TRANSPORT_TYPE_TLI
366   struct t_unitdata ud;
367   int flags = 0;
368 #endif /* HAVE_TRANSPORT_TYPE_TLI */
369 
370   /*
371    * Determine the length of the packet
372    */
373   len = MAX_PACKET_SIZE;
374 
375   /*
376    * Read the packet and check for validity
377    */
378 again:
379   src_addr_len = sizeof(src_addr);
380 #ifdef HAVE_TRANSPORT_TYPE_TLI
381   ud.addr.buf = (char *) &src_addr;
382   ud.addr.maxlen = ud.addr.len = src_addr_len;
383   ud.opt.buf = (char *) NULL;
384   ud.opt.maxlen = ud.opt.len = 0;
385   ud.udata.buf = (char *) pkt;
386   ud.udata.maxlen = ud.udata.len = len;
387   /* XXX: use flags accordingly such as if T_MORE set */
388   rc = t_rcvudata(fwd_sock, &ud, &flags);
389   if (rc == 0)			/* success, reset rc to length */
390     rc = ud.udata.len;
391   else {
392     plog(XLOG_ERROR,"fwd_reply failed: t_errno=%d, errno=%d, flags=%d",t_errno,errno, flags);
393     /*
394      * Clear error indication, otherwise the error condition persists and
395      * amd gets into an infinite loop.
396      */
397     if (t_errno == TLOOK)
398       t_rcvuderr(fwd_sock, NULL);
399   }
400 #else /* not HAVE_TRANSPORT_TYPE_TLI */
401   rc = recvfrom(fwd_sock,
402 		(char *) pkt,
403 		len,
404 		0,
405 		(struct sockaddr *) &src_addr,
406 		&src_addr_len);
407 #endif /* not HAVE_TRANSPORT_TYPE_TLI */
408 
409   /*
410    * XXX: in svr4, if the T_MORE bit of flags is set, what do
411    * we then do?  -Erez
412    */
413   if (rc < 0 || src_addr_len != sizeof(src_addr) ||
414       src_addr.sin_family != AF_INET) {
415     if (rc < 0 && errno == EINTR)
416       goto again;
417     plog(XLOG_ERROR, "Error reading RPC reply: %m");
418     goto out;
419   }
420 
421   /*
422    * Do no more work if finishing soon
423    */
424   if ((int) amd_state >= (int) Finishing)
425     goto out;
426 
427   /*
428    * Find packet reference
429    */
430   pkt_int = (u_int *) pkt;
431   pkt_xid = ntohl(*pkt_int);
432 
433   switch (pkt_xid & RPC_XID_MASK) {
434   case RPC_XID_PORTMAP:
435     dlog("Receiving PORTMAP reply %#x", pkt_xid);
436     break;
437   case RPC_XID_MOUNTD:
438     dlog("Receiving MOUNTD reply %#x", pkt_xid);
439     break;
440   case RPC_XID_NFSPING:
441     dlog("Receiving NFS ping %#x", pkt_xid);
442     break;
443   case RPC_XID_WEBNFS:
444     dlog("Receiving WebNFS lookup %#x", pkt_xid);
445     break;
446   default:
447     dlog("UNKNOWN RPC XID %#x", pkt_xid);
448     break;
449   }
450 
451   p = fwd_locate(pkt_xid);
452   if (!p) {
453     dlog("Can't forward reply id %#x", pkt_xid);
454     goto out;
455   }
456 
457   if (p->rf_fwd) {
458     /*
459      * Put the original message id back
460      * into the packet.
461      */
462     *pkt_int = htonl(p->rf_oldid);
463 
464     /*
465      * Call forwarding function
466      */
467     (*p->rf_fwd) ((voidp) pkt, rc, &src_addr, &p->rf_sin, p->rf_ptr, TRUE);
468   }
469 
470   /*
471    * Free forwarding info
472    */
473   fwd_free(p);
474 
475 out:;
476 }
477