1 /*
2 * Copyright (c) 1997-2006 Erez Zadok
3 * Copyright (c) 1989 Jan-Simon Pendry
4 * Copyright (c) 1989 Imperial College of Science, Technology & Medicine
5 * Copyright (c) 1989 The Regents of the University of California.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Jan-Simon Pendry at Imperial College, London.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgment:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 *
40 * File: am-utils/amd/rpc_fwd.c
41 *
42 */
43
44 /*
45 * RPC packet forwarding
46 */
47
48 #ifdef HAVE_CONFIG_H
49 # include <config.h>
50 #endif /* HAVE_CONFIG_H */
51 #include <am_defs.h>
52 #include <amd.h>
53
54 /*
55 * Note that the ID field in the external packet is only
56 * ever treated as a 32 bit opaque data object, so there
57 * is no need to convert to and from network byte ordering.
58 */
59
60 #define XID_ALLOC() (xid++)
61 #define MAX_PACKET_SIZE 8192 /* Maximum UDP packet size */
62
63 /*
64 * Each pending reply has an rpc_forward structure
65 * associated with it. These have a 15 second lifespan.
66 * If a new structure is required, then an expired
67 * one will be re-allocated if available, otherwise a fresh
68 * one is allocated. Whenever a reply is received the
69 * structure is discarded.
70 */
71 typedef struct rpc_forward rpc_forward;
72 struct rpc_forward {
73 qelem rf_q; /* Linked list */
74 time_t rf_ttl; /* Time to live */
75 u_int rf_xid; /* Packet id */
76 u_int rf_oldid; /* Original packet id */
77 fwd_fun *rf_fwd; /* Forwarding function */
78 voidp rf_ptr;
79 struct sockaddr_in rf_sin;
80 };
81
82 /*
83 * Head of list of pending replies
84 */
85 qelem rpc_head = {&rpc_head, &rpc_head};
86 int fwd_sock;
87 static u_int xid;
88
89
90 /*
91 * Allocate a rely structure
92 */
93 static rpc_forward *
fwd_alloc(void)94 fwd_alloc(void)
95 {
96 time_t now = clocktime(NULL);
97 rpc_forward *p = 0, *p2;
98
99 /*
100 * First search for an existing expired one.
101 */
102 ITER(p2, rpc_forward, &rpc_head) {
103 if (p2->rf_ttl <= now) {
104 p = p2;
105 break;
106 }
107 }
108
109 /*
110 * If one couldn't be found then allocate
111 * a new structure and link it at the
112 * head of the list.
113 */
114 if (p) {
115 /*
116 * Call forwarding function to say that
117 * this message was junked.
118 */
119 dlog("Re-using packet forwarding slot - id %#x", p->rf_xid);
120 if (p->rf_fwd)
121 (*p->rf_fwd) (0, 0, 0, &p->rf_sin, p->rf_ptr, FALSE);
122 rem_que(&p->rf_q);
123 } else {
124 p = ALLOC(struct rpc_forward);
125 }
126 ins_que(&p->rf_q, &rpc_head);
127
128 /*
129 * Set the time to live field
130 * Timeout in 43 seconds
131 */
132 p->rf_ttl = now + 43;
133
134 return p;
135 }
136
137
138 /*
139 * Free an allocated reply structure.
140 * First unlink it from the list, then
141 * discard it.
142 */
143 static void
fwd_free(rpc_forward * p)144 fwd_free(rpc_forward *p)
145 {
146 rem_que(&p->rf_q);
147 XFREE(p);
148 }
149
150
151 /*
152 * Initialize the RPC forwarder
153 */
154 int
fwd_init(void)155 fwd_init(void)
156 {
157 #ifdef FIONBIO
158 int on = 1;
159 #endif /* FIONBIO */
160
161 #ifdef HAVE_TRANSPORT_TYPE_TLI
162 /*
163 * Create ping TLI socket (/dev/tcp and /dev/ticlts did not work)
164 * (HPUX-11 does not like using O_NDELAY in flags)
165 */
166 fwd_sock = t_open("/dev/udp", O_RDWR|O_NONBLOCK, 0);
167 if (fwd_sock < 0) {
168 plog(XLOG_ERROR, "unable to create RPC forwarding TLI socket: %s",
169 t_errlist[t_errno]);
170 return errno;
171 }
172 #else /* not HAVE_TRANSPORT_TYPE_TLI */
173 /*
174 * Create ping socket
175 */
176 fwd_sock = socket(AF_INET, SOCK_DGRAM, 0);
177 if (fwd_sock < 0) {
178 plog(XLOG_ERROR, "unable to create RPC forwarding socket: %m");
179 return errno;
180 }
181 #endif /* not HAVE_TRANSPORT_TYPE_TLI */
182
183 /*
184 * Some things we talk to require a priv port - so make one here
185 */
186 if (bind_resv_port(fwd_sock, (u_short *) 0) < 0)
187 plog(XLOG_ERROR, "can't bind privileged port (rpc_fwd)");
188
189 if (fcntl(fwd_sock, F_SETFL, FNDELAY) < 0
190 #ifdef FIONBIO
191 && ioctl(fwd_sock, FIONBIO, &on) < 0
192 #endif /* FIONBIO */
193 ) {
194 plog(XLOG_ERROR, "Can't set non-block on forwarding socket: %m");
195 return errno;
196 }
197
198 return 0;
199 }
200
201
202 /*
203 * Locate a packet in the forwarding list
204 */
205 static rpc_forward *
fwd_locate(u_int id)206 fwd_locate(u_int id)
207 {
208 rpc_forward *p;
209
210 ITER(p, rpc_forward, &rpc_head) {
211 if (p->rf_xid == id)
212 return p;
213 }
214
215 return 0;
216 }
217
218
219 /*
220 * This is called to forward a packet to another
221 * RPC server. The message id is changed and noted
222 * so that when a reply appears we can tie it up
223 * correctly. Just matching the reply's source address
224 * would not work because it might come from a
225 * different address.
226 */
227 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)228 fwd_packet(int type_id, char *pkt, int len, struct sockaddr_in *fwdto, struct sockaddr_in *replyto, opaque_t cb_arg, fwd_fun cb)
229 {
230 rpc_forward *p;
231 u_int *pkt_int;
232 int error;
233 #ifdef HAVE_TRANSPORT_TYPE_TLI
234 struct t_unitdata ud;
235 #endif /* HAVE_TRANSPORT_TYPE_TLI */
236
237 if ((int) amd_state >= (int) Finishing)
238 return ENOENT;
239
240 /*
241 * See if the type_id is fully specified.
242 * If so, then discard any old entries
243 * for this id.
244 * Otherwise make sure the type_id is
245 * fully qualified by allocating an id here.
246 */
247 switch (type_id & RPC_XID_MASK) {
248 case RPC_XID_PORTMAP:
249 dlog("Sending PORTMAP request %#x", type_id);
250 break;
251 case RPC_XID_MOUNTD:
252 dlog("Sending MOUNTD request %#x", type_id);
253 break;
254 case RPC_XID_NFSPING:
255 dlog("Sending NFS ping %#x", type_id);
256 break;
257 case RPC_XID_WEBNFS:
258 dlog("Sending WebNFS lookup %#x", type_id);
259 break;
260 default:
261 dlog("UNKNOWN RPC XID %#x", type_id);
262 break;
263 }
264
265 if (type_id & ~RPC_XID_MASK) {
266 p = fwd_locate(type_id);
267 if (p) {
268 dlog("Discarding earlier rpc fwd handle");
269 fwd_free(p);
270 }
271 } else {
272 dlog("Allocating a new xid...");
273 type_id = MK_RPC_XID(type_id, XID_ALLOC());
274 }
275
276 p = fwd_alloc();
277 if (!p)
278 return ENOBUFS;
279
280 error = 0;
281
282 pkt_int = (u_int *) pkt;
283
284 /*
285 * Get the original packet id
286 */
287 p->rf_oldid = ntohl(*pkt_int);
288
289 /*
290 * Replace with newly allocated id
291 */
292 p->rf_xid = type_id;
293 *pkt_int = htonl(type_id);
294
295 /*
296 * The sendto may fail if, for example, the route
297 * to a remote host is lost because an intermediate
298 * gateway has gone down. Important to fill in the
299 * rest of "p" otherwise nasty things happen later...
300 */
301 #ifdef DEBUG
302 {
303 char dq[20];
304 if (p && fwdto)
305 dlog("Sending packet id %#x to %s:%d",
306 p->rf_xid,
307 inet_dquad(dq, sizeof(dq), fwdto->sin_addr.s_addr),
308 ntohs(fwdto->sin_port));
309 }
310 #endif /* DEBUG */
311
312 /* if NULL, remote server probably down */
313 if (!fwdto) {
314 error = AM_ERRNO_HOST_DOWN;
315 goto out;
316 }
317
318 #ifdef HAVE_TRANSPORT_TYPE_TLI
319 ud.addr.buf = (char *) fwdto;
320 if (fwdto) /* if NULL, set sizes to zero */
321 ud.addr.maxlen = ud.addr.len = sizeof(struct sockaddr_in);
322 else
323 ud.addr.maxlen = ud.addr.len = 0;
324 ud.opt.buf = (char *) NULL;
325 ud.opt.maxlen = ud.opt.len = 0;
326 ud.udata.buf = pkt;
327 ud.udata.maxlen = ud.udata.len = len;
328 if (t_sndudata(fwd_sock, &ud) < 0) {
329 plog(XLOG_ERROR,"fwd_packet failed: t_errno=%d, errno=%d",t_errno,errno);
330 error = errno;
331 }
332 #else /* not HAVE_TRANSPORT_TYPE_TLI */
333 if (sendto(fwd_sock, (char *) pkt, len, 0,
334 (struct sockaddr *) fwdto, sizeof(*fwdto)) < 0)
335 error = errno;
336 #endif /* not HAVE_TRANSPORT_TYPE_TLI */
337
338 /*
339 * Save callback function and return address
340 */
341 out:
342 p->rf_fwd = cb;
343 if (replyto)
344 p->rf_sin = *replyto;
345 else
346 memset((voidp) &p->rf_sin, 0, sizeof(p->rf_sin));
347 p->rf_ptr = cb_arg;
348
349 return error;
350 }
351
352
353 /*
354 * Called when some data arrives on the forwarding socket
355 */
356 void
fwd_reply(void)357 fwd_reply(void)
358 {
359 int len;
360 u_int pkt[MAX_PACKET_SIZE / sizeof(u_int) + 1];
361 u_int *pkt_int;
362 u_int pkt_xid;
363 int rc;
364 rpc_forward *p;
365 struct sockaddr_in src_addr;
366 RECVFROM_FROMLEN_TYPE src_addr_len;
367 #ifdef HAVE_TRANSPORT_TYPE_TLI
368 struct t_unitdata ud;
369 int flags = 0;
370 #endif /* HAVE_TRANSPORT_TYPE_TLI */
371
372 /*
373 * Determine the length of the packet
374 */
375 len = MAX_PACKET_SIZE;
376
377 /*
378 * Read the packet and check for validity
379 */
380 again:
381 src_addr_len = sizeof(src_addr);
382 #ifdef HAVE_TRANSPORT_TYPE_TLI
383 ud.addr.buf = (char *) &src_addr;
384 ud.addr.maxlen = ud.addr.len = src_addr_len;
385 ud.opt.buf = (char *) NULL;
386 ud.opt.maxlen = ud.opt.len = 0;
387 ud.udata.buf = (char *) pkt;
388 ud.udata.maxlen = ud.udata.len = len;
389 /* XXX: use flags accordingly such as if T_MORE set */
390 rc = t_rcvudata(fwd_sock, &ud, &flags);
391 if (rc == 0) /* success, reset rc to length */
392 rc = ud.udata.len;
393 else {
394 plog(XLOG_ERROR,"fwd_reply failed: t_errno=%d, errno=%d, flags=%d",t_errno,errno, flags);
395 /*
396 * Clear error indication, otherwise the error condition persists and
397 * amd gets into an infinite loop.
398 */
399 if (t_errno == TLOOK)
400 t_rcvuderr(fwd_sock, NULL);
401 }
402 #else /* not HAVE_TRANSPORT_TYPE_TLI */
403 rc = recvfrom(fwd_sock,
404 (char *) pkt,
405 len,
406 0,
407 (struct sockaddr *) &src_addr,
408 &src_addr_len);
409 #endif /* not HAVE_TRANSPORT_TYPE_TLI */
410
411 /*
412 * XXX: in svr4, if the T_MORE bit of flags is set, what do
413 * we then do? -Erez
414 */
415 if (rc < 0 || src_addr_len != sizeof(src_addr) ||
416 src_addr.sin_family != AF_INET) {
417 if (rc < 0 && errno == EINTR)
418 goto again;
419 plog(XLOG_ERROR, "Error reading RPC reply: %m");
420 goto out;
421 }
422
423 /*
424 * Do no more work if finishing soon
425 */
426 if ((int) amd_state >= (int) Finishing)
427 goto out;
428
429 /*
430 * Find packet reference
431 */
432 pkt_int = (u_int *) pkt;
433 pkt_xid = ntohl(*pkt_int);
434
435 switch (pkt_xid & RPC_XID_MASK) {
436 case RPC_XID_PORTMAP:
437 dlog("Receiving PORTMAP reply %#x", pkt_xid);
438 break;
439 case RPC_XID_MOUNTD:
440 dlog("Receiving MOUNTD reply %#x", pkt_xid);
441 break;
442 case RPC_XID_NFSPING:
443 dlog("Receiving NFS ping %#x", pkt_xid);
444 break;
445 case RPC_XID_WEBNFS:
446 dlog("Receiving WebNFS lookup %#x", pkt_xid);
447 break;
448 default:
449 dlog("UNKNOWN RPC XID %#x", pkt_xid);
450 break;
451 }
452
453 p = fwd_locate(pkt_xid);
454 if (!p) {
455 dlog("Can't forward reply id %#x", pkt_xid);
456 goto out;
457 }
458
459 if (p->rf_fwd) {
460 /*
461 * Put the original message id back
462 * into the packet.
463 */
464 *pkt_int = htonl(p->rf_oldid);
465
466 /*
467 * Call forwarding function
468 */
469 (*p->rf_fwd) ((voidp) pkt, rc, &src_addr, &p->rf_sin, p->rf_ptr, TRUE);
470 }
471
472 /*
473 * Free forwarding info
474 */
475 fwd_free(p);
476
477 out:;
478 }
479