2 * xdr_rec.c, Implements TCP/IP based XDR streams with a "record marking"
3 * layer above tcp (for rpc's use).
5 * Copyright (c) 2010, Oracle America, Inc.
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34 * These routines interface XDRSTREAMS to a tcp/ip connection.
35 * There is a record marking layer between the xdr stream
36 * and the tcp transport level. A record is composed on one or more
37 * record fragments. A record fragment is a thirty-two bit header followed
38 * by n bytes of data, where n is contained in the header. The header
39 * is represented as a htonl(u_long). The high order bit encodes
40 * whether or not the fragment is the last fragment of the record
41 * (1 => fragment is last, 0 => more fragments to follow.
42 * The other 31 bits encode the byte length of the fragment.
51 #include <libio/iolibio.h>
53 static bool_t xdrrec_getlong (XDR *, long *);
54 static bool_t xdrrec_putlong (XDR *, const long *);
55 static bool_t xdrrec_getbytes (XDR *, caddr_t, u_int);
56 static bool_t xdrrec_putbytes (XDR *, const char *, u_int);
57 static u_int xdrrec_getpos (const XDR *);
58 static bool_t xdrrec_setpos (XDR *, u_int);
59 static int32_t *xdrrec_inline (XDR *, u_int);
60 static void xdrrec_destroy (XDR *);
61 static bool_t xdrrec_getint32 (XDR *, int32_t *);
62 static bool_t xdrrec_putint32 (XDR *, const int32_t *);
64 static const struct xdr_ops xdrrec_ops = {
78 * A record is composed of one or more record fragments.
79 * A record fragment is a two-byte header followed by zero to
80 * 2**32-1 bytes. The header is treated as a long unsigned and is
81 * encode/decoded to the network via htonl/ntohl. The low order 31 bits
82 * are a byte count of the fragment. The highest order bit is a boolean:
83 * 1 => this fragment is the last fragment of the record,
84 * 0 => this fragment is followed by more fragment(s).
86 * The fragment/record machinery is not general; it is constructed to
87 * meet the needs of xdr and rpc based on tcp.
90 #define LAST_FRAG (1UL << 31)
92 typedef struct rec_strm
99 int (*writeit) (char *, char *, int);
100 caddr_t out_base; /* output buffer (points to frag header) */
101 caddr_t out_finger; /* next output position */
102 caddr_t out_boundry; /* data cannot up to this address */
103 u_int32_t *frag_header; /* beginning of curren fragment */
104 bool_t frag_sent; /* true if buffer sent in middle of record */
108 int (*readit) (char *, char *, int);
109 u_long in_size; /* fixed size of the input buffer */
111 caddr_t in_finger; /* location of next byte to be had */
112 caddr_t in_boundry; /* can read up to this location */
113 long fbtbc; /* fragment bytes to be consumed */
120 static u_int fix_buf_size (u_int) internal_function;
121 static bool_t skip_input_bytes (RECSTREAM *, long) internal_function;
122 static bool_t flush_out (RECSTREAM *, bool_t) internal_function;
123 static bool_t set_input_fragment (RECSTREAM *) internal_function;
124 static bool_t get_input_bytes (RECSTREAM *, caddr_t, int) internal_function;
127 * Create an xdr handle for xdrrec
128 * xdrrec_create fills in xdrs. Sendsize and recvsize are
129 * send and recv buffer sizes (0 => use default).
130 * tcp_handle is an opaque handle that is passed as the first parameter to
131 * the procedures readit and writeit. Readit and writeit are read and
132 * write respectively. They are like the system
133 * calls expect that they take an opaque handle rather than an fd.
136 xdrrec_create (XDR *xdrs, u_int sendsize,
137 u_int recvsize, caddr_t tcp_handle,
138 int (*readit) (char *, char *, int),
139 int (*writeit) (char *, char *, int))
141 RECSTREAM *rstrm = (RECSTREAM *) mem_alloc (sizeof (RECSTREAM));
145 sendsize = fix_buf_size (sendsize);
146 recvsize = fix_buf_size (recvsize);
147 buf = mem_alloc (sendsize + recvsize + BYTES_PER_XDR_UNIT);
149 if (rstrm == NULL || buf == NULL)
151 (void) __fxprintf (NULL, "%s: %s", __func__, _("out of memory\n"));
152 mem_free (rstrm, sizeof (RECSTREAM));
153 mem_free (buf, sendsize + recvsize + BYTES_PER_XDR_UNIT);
155 * This is bad. Should rework xdrrec_create to
156 * return a handle, and in this case return NULL
161 * adjust sizes and allocate buffer quad byte aligned
163 rstrm->sendsize = sendsize;
164 rstrm->recvsize = recvsize;
165 rstrm->the_buffer = buf;
166 tmp = rstrm->the_buffer;
167 if ((size_t)tmp % BYTES_PER_XDR_UNIT)
168 tmp += BYTES_PER_XDR_UNIT - (size_t)tmp % BYTES_PER_XDR_UNIT;
169 rstrm->out_base = tmp;
170 rstrm->in_base = tmp + sendsize;
174 /* We have to add the cast since the `struct xdr_ops' in `struct XDR'
176 xdrs->x_ops = (struct xdr_ops *) &xdrrec_ops;
177 xdrs->x_private = (caddr_t) rstrm;
178 rstrm->tcp_handle = tcp_handle;
179 rstrm->readit = readit;
180 rstrm->writeit = writeit;
181 rstrm->out_finger = rstrm->out_boundry = rstrm->out_base;
182 rstrm->frag_header = (u_int32_t *) rstrm->out_base;
183 rstrm->out_finger += 4;
184 rstrm->out_boundry += sendsize;
185 rstrm->frag_sent = FALSE;
186 rstrm->in_size = recvsize;
187 rstrm->in_boundry = rstrm->in_base;
188 rstrm->in_finger = (rstrm->in_boundry += recvsize);
190 rstrm->last_frag = TRUE;
192 libc_hidden_nolink_sunrpc (xdrrec_create, GLIBC_2_0)
196 * The routines defined below are the xdr ops which will go into the
197 * xdr handle filled in by xdrrec_create.
201 xdrrec_getlong (XDR *xdrs, long *lp)
203 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
204 int32_t *buflp = (int32_t *) rstrm->in_finger;
207 /* first try the inline, fast case */
208 if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
209 rstrm->in_boundry - (char *) buflp >= BYTES_PER_XDR_UNIT)
211 *lp = (int32_t) ntohl (*buflp);
212 rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
213 rstrm->in_finger += BYTES_PER_XDR_UNIT;
217 if (!xdrrec_getbytes (xdrs, (caddr_t) & mylong,
220 *lp = (int32_t) ntohl (mylong);
226 xdrrec_putlong (XDR *xdrs, const long *lp)
228 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
229 int32_t *dest_lp = (int32_t *) rstrm->out_finger;
231 if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
234 * this case should almost never happen so the code is
237 rstrm->out_finger -= BYTES_PER_XDR_UNIT;
238 rstrm->frag_sent = TRUE;
239 if (!flush_out (rstrm, FALSE))
241 dest_lp = (int32_t *) rstrm->out_finger;
242 rstrm->out_finger += BYTES_PER_XDR_UNIT;
244 *dest_lp = htonl (*lp);
248 static bool_t /* must manage buffers, fragments, and records */
249 xdrrec_getbytes (XDR *xdrs, caddr_t addr, u_int len)
251 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
256 current = rstrm->fbtbc;
259 if (rstrm->last_frag)
261 if (!set_input_fragment (rstrm))
265 current = (len < current) ? len : current;
266 if (!get_input_bytes (rstrm, addr, current))
269 rstrm->fbtbc -= current;
276 xdrrec_putbytes (XDR *xdrs, const char *addr, u_int len)
278 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
283 current = rstrm->out_boundry - rstrm->out_finger;
284 current = (len < current) ? len : current;
285 memcpy (rstrm->out_finger, addr, current);
286 rstrm->out_finger += current;
289 if (rstrm->out_finger == rstrm->out_boundry && len > 0)
291 rstrm->frag_sent = TRUE;
292 if (!flush_out (rstrm, FALSE))
300 xdrrec_getpos (const XDR *xdrs)
302 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
305 pos = __lseek ((int) (long) rstrm->tcp_handle, (long) 0, 1);
311 pos += rstrm->out_finger - rstrm->out_base;
315 pos -= rstrm->in_boundry - rstrm->in_finger;
326 xdrrec_setpos (XDR *xdrs, u_int pos)
328 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
329 u_int currpos = xdrrec_getpos (xdrs);
330 int delta = currpos - pos;
333 if ((int) currpos != -1)
338 newpos = rstrm->out_finger - delta;
339 if (newpos > (caddr_t) rstrm->frag_header &&
340 newpos < rstrm->out_boundry)
342 rstrm->out_finger = newpos;
348 newpos = rstrm->in_finger - delta;
349 if ((delta < (int) (rstrm->fbtbc)) &&
350 (newpos <= rstrm->in_boundry) &&
351 (newpos >= rstrm->in_base))
353 rstrm->in_finger = newpos;
354 rstrm->fbtbc -= delta;
366 xdrrec_inline (XDR *xdrs, u_int len)
368 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
375 if ((rstrm->out_finger + len) <= rstrm->out_boundry)
377 buf = (int32_t *) rstrm->out_finger;
378 rstrm->out_finger += len;
383 if ((len <= rstrm->fbtbc) &&
384 ((rstrm->in_finger + len) <= rstrm->in_boundry))
386 buf = (int32_t *) rstrm->in_finger;
388 rstrm->in_finger += len;
399 xdrrec_destroy (XDR *xdrs)
401 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
403 mem_free (rstrm->the_buffer,
404 rstrm->sendsize + rstrm->recvsize + BYTES_PER_XDR_UNIT);
405 mem_free ((caddr_t) rstrm, sizeof (RECSTREAM));
409 xdrrec_getint32 (XDR *xdrs, int32_t *ip)
411 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
412 int32_t *bufip = (int32_t *) rstrm->in_finger;
415 /* first try the inline, fast case */
416 if (rstrm->fbtbc >= BYTES_PER_XDR_UNIT &&
417 rstrm->in_boundry - (char *) bufip >= BYTES_PER_XDR_UNIT)
419 *ip = ntohl (*bufip);
420 rstrm->fbtbc -= BYTES_PER_XDR_UNIT;
421 rstrm->in_finger += BYTES_PER_XDR_UNIT;
425 if (!xdrrec_getbytes (xdrs, (caddr_t) &mylong,
428 *ip = ntohl (mylong);
434 xdrrec_putint32 (XDR *xdrs, const int32_t *ip)
436 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
437 int32_t *dest_ip = (int32_t *) rstrm->out_finger;
439 if ((rstrm->out_finger += BYTES_PER_XDR_UNIT) > rstrm->out_boundry)
442 * this case should almost never happen so the code is
445 rstrm->out_finger -= BYTES_PER_XDR_UNIT;
446 rstrm->frag_sent = TRUE;
447 if (!flush_out (rstrm, FALSE))
449 dest_ip = (int32_t *) rstrm->out_finger;
450 rstrm->out_finger += BYTES_PER_XDR_UNIT;
452 *dest_ip = htonl (*ip);
457 * Exported routines to manage xdr records
461 * Before reading (deserializing from the stream, one should always call
462 * this procedure to guarantee proper record alignment.
465 xdrrec_skiprecord (XDR *xdrs)
467 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
469 while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
471 if (!skip_input_bytes (rstrm, rstrm->fbtbc))
474 if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
477 rstrm->last_frag = FALSE;
480 libc_hidden_nolink_sunrpc (xdrrec_skiprecord, GLIBC_2_0)
483 * Lookahead function.
484 * Returns TRUE iff there is no more input in the buffer
485 * after consuming the rest of the current record.
488 xdrrec_eof (XDR *xdrs)
490 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
492 while (rstrm->fbtbc > 0 || (!rstrm->last_frag))
494 if (!skip_input_bytes (rstrm, rstrm->fbtbc))
497 if ((!rstrm->last_frag) && (!set_input_fragment (rstrm)))
500 if (rstrm->in_finger == rstrm->in_boundry)
504 libc_hidden_nolink_sunrpc (xdrrec_eof, GLIBC_2_0)
507 * The client must tell the package when an end-of-record has occurred.
508 * The second parameter tells whether the record should be flushed to the
509 * (output) tcp stream. (This lets the package support batched or
510 * pipelined procedure calls.) TRUE => immediate flush to tcp connection.
513 xdrrec_endofrecord (XDR *xdrs, bool_t sendnow)
515 RECSTREAM *rstrm = (RECSTREAM *) xdrs->x_private;
516 u_long len; /* fragment length */
518 if (sendnow || rstrm->frag_sent
519 || rstrm->out_finger + BYTES_PER_XDR_UNIT >= rstrm->out_boundry)
521 rstrm->frag_sent = FALSE;
522 return flush_out (rstrm, TRUE);
524 len = (rstrm->out_finger - (char *) rstrm->frag_header
525 - BYTES_PER_XDR_UNIT);
526 *rstrm->frag_header = htonl ((u_long) len | LAST_FRAG);
527 rstrm->frag_header = (u_int32_t *) rstrm->out_finger;
528 rstrm->out_finger += BYTES_PER_XDR_UNIT;
531 libc_hidden_nolink_sunrpc (xdrrec_endofrecord, GLIBC_2_0)
535 * Internal useful routines
539 flush_out (RECSTREAM *rstrm, bool_t eor)
541 u_long eormask = (eor == TRUE) ? LAST_FRAG : 0;
542 u_long len = (rstrm->out_finger - (char *) rstrm->frag_header
543 - BYTES_PER_XDR_UNIT);
545 *rstrm->frag_header = htonl (len | eormask);
546 len = rstrm->out_finger - rstrm->out_base;
547 if ((*(rstrm->writeit)) (rstrm->tcp_handle, rstrm->out_base, (int) len)
550 rstrm->frag_header = (u_int32_t *) rstrm->out_base;
551 rstrm->out_finger = (caddr_t) rstrm->out_base + BYTES_PER_XDR_UNIT;
555 static bool_t /* knows nothing about records! Only about input buffers */
556 fill_input_buf (RECSTREAM *rstrm)
562 where = rstrm->in_base;
563 i = (size_t) rstrm->in_boundry % BYTES_PER_XDR_UNIT;
565 len = rstrm->in_size - i;
566 if ((len = (*(rstrm->readit)) (rstrm->tcp_handle, where, len)) == -1)
568 rstrm->in_finger = where;
570 rstrm->in_boundry = where;
574 static bool_t /* knows nothing about records! Only about input buffers */
576 get_input_bytes (RECSTREAM *rstrm, caddr_t addr, int len)
582 current = rstrm->in_boundry - rstrm->in_finger;
585 if (!fill_input_buf (rstrm))
589 current = (len < current) ? len : current;
590 memcpy (addr, rstrm->in_finger, current);
591 rstrm->in_finger += current;
598 static bool_t /* next two bytes of the input stream are treated as a header */
600 set_input_fragment (RECSTREAM *rstrm)
604 if (! get_input_bytes (rstrm, (caddr_t)&header, BYTES_PER_XDR_UNIT))
606 header = ntohl (header);
607 rstrm->last_frag = ((header & LAST_FRAG) == 0) ? FALSE : TRUE;
609 * Sanity check. Try not to accept wildly incorrect fragment
610 * sizes. Unfortunately, only a size of zero can be identified as
611 * 'wildely incorrect', and this only, if it is not the last
612 * fragment of a message. Ridiculously large fragment sizes may look
613 * wrong, but we don't have any way to be certain that they aren't
614 * what the client actually intended to send us. Many existing RPC
615 * implementations may sent a fragment of size zero as the last
616 * fragment of a message.
620 rstrm->fbtbc = header & ~LAST_FRAG;
624 static bool_t /* consumes input bytes; knows nothing about records! */
626 skip_input_bytes (RECSTREAM *rstrm, long cnt)
632 current = rstrm->in_boundry - rstrm->in_finger;
635 if (!fill_input_buf (rstrm))
639 current = (cnt < current) ? cnt : current;
640 rstrm->in_finger += current;
648 fix_buf_size (u_int s)