xdr_mbuf.c revision 184921
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: head/sys/xdr/xdr_mbuf.c 184921 2008-11-13 14:36:52Z dfr $"); 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 MGET(m, 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 MGET(n, M_TRYWAIT, m->m_type); 232 if (m->m_flags & M_EXT) 233 MCLGET(n, M_TRYWAIT); 234 m->m_next = n; 235 } 236 m = m->m_next; 237 xdrs->x_private = (void *) m; 238 xdrs->x_handy = 0; 239 } 240 } 241 242 return (TRUE); 243} 244 245static u_int 246xdrmbuf_getpos(XDR *xdrs) 247{ 248 struct mbuf *m0 = (struct mbuf *) xdrs->x_base; 249 struct mbuf *m = (struct mbuf *) xdrs->x_private; 250 u_int pos = 0; 251 252 while (m0 && m0 != m) { 253 pos += m0->m_len; 254 m0 = m0->m_next; 255 } 256 KASSERT(m0, ("Corrupted mbuf chain")); 257 258 return (pos + xdrs->x_handy); 259} 260 261static bool_t 262xdrmbuf_setpos(XDR *xdrs, u_int pos) 263{ 264 struct mbuf *m = (struct mbuf *) xdrs->x_base; 265 266 while (m && pos > m->m_len) { 267 pos -= m->m_len; 268 m = m->m_next; 269 } 270 KASSERT(m, ("Corrupted mbuf chain")); 271 272 xdrs->x_private = (void *) m; 273 xdrs->x_handy = pos; 274 275 return (TRUE); 276} 277 278static int32_t * 279xdrmbuf_inline(XDR *xdrs, u_int len) 280{ 281 struct mbuf *m = (struct mbuf *) xdrs->x_private; 282 size_t available; 283 char *p; 284 285 if (xdrs->x_op == XDR_ENCODE) { 286 available = M_TRAILINGSPACE(m) + (m->m_len - xdrs->x_handy); 287 } else { 288 available = m->m_len - xdrs->x_handy; 289 } 290 291 if (available >= len) { 292 p = mtod(m, char *) + xdrs->x_handy; 293 if (((uintptr_t) p) & (sizeof(int32_t) - 1)) 294 return (0); 295 xdrs->x_handy += len; 296 if (xdrs->x_handy > m->m_len) 297 m->m_len = xdrs->x_handy; 298 return ((int32_t *) p); 299 } 300 301 return (0); 302} 303