1/*-
2 * Copyright (c) 2008 Isilon Inc http://www.isilon.com/
3 * Authors: Doug Rabson <dfr@rabson.org>
4 * Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD$");
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/malloc.h>
34#include <sys/mbuf.h>
35
36#include <rpc/types.h>
37#include <rpc/xdr.h>
38
39static void xdrmbuf_destroy(XDR *);
40static bool_t xdrmbuf_getlong(XDR *, long *);
41static bool_t xdrmbuf_putlong(XDR *, const long *);
42static bool_t xdrmbuf_getbytes(XDR *, char *, u_int);
43static bool_t xdrmbuf_putbytes(XDR *, const char *, u_int);
44/* XXX: w/64-bit pointers, u_int not enough! */
45static u_int xdrmbuf_getpos(XDR *);
46static bool_t xdrmbuf_setpos(XDR *, u_int);
47static int32_t *xdrmbuf_inline(XDR *, u_int);
48
49static const struct	xdr_ops xdrmbuf_ops = {
50	xdrmbuf_getlong,
51	xdrmbuf_putlong,
52	xdrmbuf_getbytes,
53	xdrmbuf_putbytes,
54	xdrmbuf_getpos,
55	xdrmbuf_setpos,
56	xdrmbuf_inline,
57	xdrmbuf_destroy
58};
59
60/*
61 * The procedure xdrmbuf_create initializes a stream descriptor for a
62 * mbuf.
63 */
64void
65xdrmbuf_create(XDR *xdrs, struct mbuf *m, enum xdr_op op)
66{
67
68	KASSERT(m != NULL, ("xdrmbuf_create with NULL mbuf chain"));
69	xdrs->x_op = op;
70	xdrs->x_ops = &xdrmbuf_ops;
71	xdrs->x_base = (char *) m;
72	if (op == XDR_ENCODE) {
73		m = m_last(m);
74		xdrs->x_private = m;
75		xdrs->x_handy = m->m_len;
76	} else {
77		xdrs->x_private = m;
78		xdrs->x_handy = 0;
79	}
80}
81
82void
83xdrmbuf_append(XDR *xdrs, struct mbuf *madd)
84{
85	struct mbuf *m;
86
87	KASSERT(xdrs->x_ops == &xdrmbuf_ops && xdrs->x_op == XDR_ENCODE,
88	    ("xdrmbuf_append: invalid XDR stream"));
89
90	if (m_length(madd, NULL) == 0) {
91		m_freem(madd);
92		return;
93	}
94
95	m = (struct mbuf *) xdrs->x_private;
96	m->m_next = madd;
97
98	m = m_last(madd);
99	xdrs->x_private = m;
100	xdrs->x_handy = m->m_len;
101}
102
103struct mbuf *
104xdrmbuf_getall(XDR *xdrs)
105{
106	struct mbuf *m0, *m;
107
108	KASSERT(xdrs->x_ops == &xdrmbuf_ops && xdrs->x_op == XDR_DECODE,
109	    ("xdrmbuf_append: invalid XDR stream"));
110
111	m0 = (struct mbuf *) xdrs->x_base;
112	m = (struct mbuf *) xdrs->x_private;
113	if (m0 != m) {
114		while (m0->m_next != m)
115			m0 = m0->m_next;
116		m0->m_next = NULL;
117		xdrs->x_private = NULL;
118	} else {
119		xdrs->x_base = NULL;
120		xdrs->x_private = NULL;
121	}
122
123	if (m)
124		m_adj(m, xdrs->x_handy);
125	else
126		m = m_get(M_WAITOK, MT_DATA);
127	return (m);
128}
129
130static void
131xdrmbuf_destroy(XDR *xdrs)
132{
133
134	if (xdrs->x_op == XDR_DECODE && xdrs->x_base) {
135		m_freem((struct mbuf *) xdrs->x_base);
136		xdrs->x_base = NULL;
137		xdrs->x_private = NULL;
138	}
139}
140
141static bool_t
142xdrmbuf_getlong(XDR *xdrs, long *lp)
143{
144	int32_t *p;
145	int32_t t;
146
147	p = xdrmbuf_inline(xdrs, sizeof(int32_t));
148	if (p) {
149		t = *p;
150	} else {
151		xdrmbuf_getbytes(xdrs, (char *) &t, sizeof(int32_t));
152	}
153
154	*lp = ntohl(t);
155	return (TRUE);
156}
157
158static bool_t
159xdrmbuf_putlong(xdrs, lp)
160	XDR *xdrs;
161	const long *lp;
162{
163	int32_t *p;
164	int32_t t = htonl(*lp);
165
166	p = xdrmbuf_inline(xdrs, sizeof(int32_t));
167	if (p) {
168		*p = t;
169		return (TRUE);
170	} else {
171		return (xdrmbuf_putbytes(xdrs, (char *) &t, sizeof(int32_t)));
172	}
173}
174
175static bool_t
176xdrmbuf_getbytes(XDR *xdrs, char *addr, u_int len)
177{
178	struct mbuf *m = (struct mbuf *) xdrs->x_private;
179	size_t sz;
180
181	while (len > 0) {
182		/*
183		 * Make sure we haven't hit the end.
184		 */
185		if (!m) {
186			return (FALSE);
187		}
188
189		/*
190		 * See how much we can get from this mbuf.
191		 */
192		sz = m->m_len - xdrs->x_handy;
193		if (sz > len)
194			sz = len;
195		bcopy(mtod(m, const char *) + xdrs->x_handy, addr, sz);
196
197		addr += sz;
198		xdrs->x_handy += sz;
199		len -= sz;
200
201		if (xdrs->x_handy == m->m_len) {
202			m = m->m_next;
203			xdrs->x_private = (void *) m;
204			xdrs->x_handy = 0;
205		}
206	}
207
208	return (TRUE);
209}
210
211static bool_t
212xdrmbuf_putbytes(XDR *xdrs, const char *addr, u_int len)
213{
214	struct mbuf *m = (struct mbuf *) xdrs->x_private;
215	struct mbuf *n;
216	size_t sz;
217
218	while (len > 0) {
219		sz = M_TRAILINGSPACE(m) + (m->m_len - xdrs->x_handy);
220		if (sz > len)
221			sz = len;
222		bcopy(addr, mtod(m, char *) + xdrs->x_handy, sz);
223		addr += sz;
224		xdrs->x_handy += sz;
225		if (xdrs->x_handy > m->m_len)
226			m->m_len = xdrs->x_handy;
227		len -= sz;
228
229		if (xdrs->x_handy == m->m_len && M_TRAILINGSPACE(m) == 0) {
230			if (!m->m_next) {
231				if (m->m_flags & M_EXT)
232					n = m_getcl(M_WAITOK, m->m_type, 0);
233				else
234					n = m_get(M_WAITOK, m->m_type);
235				m->m_next = n;
236			}
237			m = m->m_next;
238			xdrs->x_private = (void *) m;
239			xdrs->x_handy = 0;
240		}
241	}
242
243	return (TRUE);
244}
245
246static u_int
247xdrmbuf_getpos(XDR *xdrs)
248{
249	struct mbuf *m0 = (struct mbuf *) xdrs->x_base;
250	struct mbuf *m = (struct mbuf *) xdrs->x_private;
251	u_int pos = 0;
252
253	while (m0 && m0 != m) {
254		pos += m0->m_len;
255		m0 = m0->m_next;
256	}
257	KASSERT(m0, ("Corrupted mbuf chain"));
258
259	return (pos + xdrs->x_handy);
260}
261
262static bool_t
263xdrmbuf_setpos(XDR *xdrs, u_int pos)
264{
265	struct mbuf *m = (struct mbuf *) xdrs->x_base;
266
267	while (m && pos > m->m_len) {
268		pos -= m->m_len;
269		m = m->m_next;
270	}
271	KASSERT(m, ("Corrupted mbuf chain"));
272
273	xdrs->x_private = (void *) m;
274	xdrs->x_handy = pos;
275
276	return (TRUE);
277}
278
279static int32_t *
280xdrmbuf_inline(XDR *xdrs, u_int len)
281{
282	struct mbuf *m = (struct mbuf *) xdrs->x_private;
283	size_t available;
284	char *p;
285
286	if (!m)
287		return (0);
288	if (xdrs->x_op == XDR_ENCODE) {
289		available = M_TRAILINGSPACE(m) + (m->m_len - xdrs->x_handy);
290	} else {
291		available = m->m_len - xdrs->x_handy;
292	}
293
294	if (available >= len) {
295		p = mtod(m, char *) + xdrs->x_handy;
296		if (((uintptr_t) p) & (sizeof(int32_t) - 1))
297			return (0);
298		xdrs->x_handy += len;
299		if (xdrs->x_handy > m->m_len)
300			m->m_len = xdrs->x_handy;
301		return ((int32_t *) p);
302	}
303
304	return (0);
305}
306