sys/xdr/xdr_mbuf.c

   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
  39 static void xdrmbuf_destroy(XDR *);
  40 static bool_t xdrmbuf_getlong(XDR *, long *);
  41 static bool_t xdrmbuf_putlong(XDR *, const long *);
  42 static bool_t xdrmbuf_getbytes(XDR *, char *, u_int);
  43 static bool_t xdrmbuf_putbytes(XDR *, const char *, u_int);
  44 /* XXX: w/64-bit pointers, u_int not enough! */
  45 static u_int xdrmbuf_getpos(XDR *);
  46 static bool_t xdrmbuf_setpos(XDR *, u_int);
  47 static int32_t *xdrmbuf_inline(XDR *, u_int);
  48
  49 static 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  */
  64 void
  65 xdrmbuf_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
  82 void
  83 xdrmbuf_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
 103 struct mbuf *
 104 xdrmbuf_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
 130 static void
 131 xdrmbuf_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
 141 static bool_t
 142 xdrmbuf_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
 158 static bool_t
 159 xdrmbuf_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
 175 static bool_t
 176 xdrmbuf_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
 211 static bool_t
 212 xdrmbuf_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
 246 static u_int
 247 xdrmbuf_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
 262 static bool_t
 263 xdrmbuf_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
 279 static int32_t *
 280 xdrmbuf_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 }