The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_mchain.c

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    1 /*-
    2  * Copyright (c) 2000, 2001 Boris Popov
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the author nor the names of any co-contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD: releng/8.0/sys/kern/subr_mchain.c 177599 2008-03-25 09:39:02Z ru $");
   32 
   33 #include <sys/param.h>
   34 #include <sys/systm.h>
   35 #include <sys/endian.h>
   36 #include <sys/errno.h>
   37 #include <sys/mbuf.h>
   38 #include <sys/module.h>
   39 #include <sys/uio.h>
   40 
   41 #include <sys/mchain.h>
   42 
   43 MODULE_VERSION(libmchain, 1);
   44 
   45 #define MBERROR(format, ...) printf("%s(%d): "format, __func__ , \
   46                                     __LINE__ , ## __VA_ARGS__)
   47 
   48 #define MBPANIC(format, ...) printf("%s(%d): "format, __func__ , \
   49                                     __LINE__ , ## __VA_ARGS__)
   50 
   51 /*
   52  * Various helper functions
   53  */
   54 int
   55 mb_init(struct mbchain *mbp)
   56 {
   57         struct mbuf *m;
   58 
   59         m = m_gethdr(M_WAIT, MT_DATA);
   60         m->m_len = 0;
   61         mb_initm(mbp, m);
   62         return 0;
   63 }
   64 
   65 void
   66 mb_initm(struct mbchain *mbp, struct mbuf *m)
   67 {
   68         bzero(mbp, sizeof(*mbp));
   69         mbp->mb_top = mbp->mb_cur = m;
   70         mbp->mb_mleft = M_TRAILINGSPACE(m);
   71 }
   72 
   73 void
   74 mb_done(struct mbchain *mbp)
   75 {
   76         if (mbp->mb_top) {
   77                 m_freem(mbp->mb_top);
   78                 mbp->mb_top = NULL;
   79         }
   80 }
   81 
   82 struct mbuf *
   83 mb_detach(struct mbchain *mbp)
   84 {
   85         struct mbuf *m;
   86 
   87         m = mbp->mb_top;
   88         mbp->mb_top = NULL;
   89         return m;
   90 }
   91 
   92 int
   93 mb_fixhdr(struct mbchain *mbp)
   94 {
   95         return mbp->mb_top->m_pkthdr.len = m_fixhdr(mbp->mb_top);
   96 }
   97 
   98 /*
   99  * Check if object of size 'size' fit to the current position and
  100  * allocate new mbuf if not. Advance pointers and increase length of mbuf(s).
  101  * Return pointer to the object placeholder or NULL if any error occured.
  102  * Note: size should be <= MLEN 
  103  */
  104 caddr_t
  105 mb_reserve(struct mbchain *mbp, int size)
  106 {
  107         struct mbuf *m, *mn;
  108         caddr_t bpos;
  109 
  110         if (size > MLEN)
  111                 panic("mb_reserve: size = %d\n", size);
  112         m = mbp->mb_cur;
  113         if (mbp->mb_mleft < size) {
  114                 mn = m_get(M_WAIT, MT_DATA);
  115                 mbp->mb_cur = m->m_next = mn;
  116                 m = mn;
  117                 m->m_len = 0;
  118                 mbp->mb_mleft = M_TRAILINGSPACE(m);
  119         }
  120         mbp->mb_mleft -= size;
  121         mbp->mb_count += size;
  122         bpos = mtod(m, caddr_t) + m->m_len;
  123         m->m_len += size;
  124         return bpos;
  125 }
  126 
  127 int
  128 mb_put_uint8(struct mbchain *mbp, u_int8_t x)
  129 {
  130         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  131 }
  132 
  133 int
  134 mb_put_uint16be(struct mbchain *mbp, u_int16_t x)
  135 {
  136         x = htobe16(x);
  137         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  138 }
  139 
  140 int
  141 mb_put_uint16le(struct mbchain *mbp, u_int16_t x)
  142 {
  143         x = htole16(x);
  144         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  145 }
  146 
  147 int
  148 mb_put_uint32be(struct mbchain *mbp, u_int32_t x)
  149 {
  150         x = htobe32(x);
  151         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  152 }
  153 
  154 int
  155 mb_put_uint32le(struct mbchain *mbp, u_int32_t x)
  156 {
  157         x = htole32(x);
  158         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  159 }
  160 
  161 int
  162 mb_put_int64be(struct mbchain *mbp, int64_t x)
  163 {
  164         x = htobe64(x);
  165         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  166 }
  167 
  168 int
  169 mb_put_int64le(struct mbchain *mbp, int64_t x)
  170 {
  171         x = htole64(x);
  172         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  173 }
  174 
  175 int
  176 mb_put_mem(struct mbchain *mbp, c_caddr_t source, int size, int type)
  177 {
  178         struct mbuf *m;
  179         caddr_t dst;
  180         c_caddr_t src;
  181         int cplen, error, mleft, count;
  182         size_t srclen, dstlen;
  183 
  184         m = mbp->mb_cur;
  185         mleft = mbp->mb_mleft;
  186 
  187         while (size > 0) {
  188                 if (mleft == 0) {
  189                         if (m->m_next == NULL)
  190                                 m = m_getm(m, size, M_WAIT, MT_DATA);
  191                         else
  192                                 m = m->m_next;
  193                         mleft = M_TRAILINGSPACE(m);
  194                         continue;
  195                 }
  196                 cplen = mleft > size ? size : mleft;
  197                 srclen = dstlen = cplen;
  198                 dst = mtod(m, caddr_t) + m->m_len;
  199                 switch (type) {
  200                     case MB_MCUSTOM:
  201                         srclen = size;
  202                         dstlen = mleft;
  203                         error = mbp->mb_copy(mbp, source, dst, &srclen, &dstlen);
  204                         if (error)
  205                                 return error;
  206                         break;
  207                     case MB_MINLINE:
  208                         for (src = source, count = cplen; count; count--)
  209                                 *dst++ = *src++;
  210                         break;
  211                     case MB_MSYSTEM:
  212                         bcopy(source, dst, cplen);
  213                         break;
  214                     case MB_MUSER:
  215                         error = copyin(source, dst, cplen);
  216                         if (error)
  217                                 return error;
  218                         break;
  219                     case MB_MZERO:
  220                         bzero(dst, cplen);
  221                         break;
  222                 }
  223                 size -= srclen;
  224                 source += srclen;
  225                 m->m_len += dstlen;
  226                 mleft -= dstlen;
  227                 mbp->mb_count += dstlen;
  228         }
  229         mbp->mb_cur = m;
  230         mbp->mb_mleft = mleft;
  231         return 0;
  232 }
  233 
  234 int
  235 mb_put_mbuf(struct mbchain *mbp, struct mbuf *m)
  236 {
  237         mbp->mb_cur->m_next = m;
  238         while (m) {
  239                 mbp->mb_count += m->m_len;
  240                 if (m->m_next == NULL)
  241                         break;
  242                 m = m->m_next;
  243         }
  244         mbp->mb_mleft = M_TRAILINGSPACE(m);
  245         mbp->mb_cur = m;
  246         return 0;
  247 }
  248 
  249 /*
  250  * copies a uio scatter/gather list to an mbuf chain.
  251  */
  252 int
  253 mb_put_uio(struct mbchain *mbp, struct uio *uiop, int size)
  254 {
  255         long left;
  256         int mtype, error;
  257 
  258         mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
  259 
  260         while (size > 0 && uiop->uio_resid) {
  261                 if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
  262                         return EFBIG;
  263                 left = uiop->uio_iov->iov_len;
  264                 if (left == 0) {
  265                         uiop->uio_iov++;
  266                         uiop->uio_iovcnt--;
  267                         continue;
  268                 }
  269                 if (left > size)
  270                         left = size;
  271                 error = mb_put_mem(mbp, uiop->uio_iov->iov_base, left, mtype);
  272                 if (error)
  273                         return error;
  274                 uiop->uio_offset += left;
  275                 uiop->uio_resid -= left;
  276                 uiop->uio_iov->iov_base =
  277                     (char *)uiop->uio_iov->iov_base + left;
  278                 uiop->uio_iov->iov_len -= left;
  279                 size -= left;
  280         }
  281         return 0;
  282 }
  283 
  284 /*
  285  * Routines for fetching data from an mbuf chain
  286  */
  287 int
  288 md_init(struct mdchain *mdp)
  289 {
  290         struct mbuf *m;
  291 
  292         m = m_gethdr(M_WAIT, MT_DATA);
  293         m->m_len = 0;
  294         md_initm(mdp, m);
  295         return 0;
  296 }
  297 
  298 void
  299 md_initm(struct mdchain *mdp, struct mbuf *m)
  300 {
  301         bzero(mdp, sizeof(*mdp));
  302         mdp->md_top = mdp->md_cur = m;
  303         mdp->md_pos = mtod(m, u_char*);
  304 }
  305 
  306 void
  307 md_done(struct mdchain *mdp)
  308 {
  309         if (mdp->md_top) {
  310                 m_freem(mdp->md_top);
  311                 mdp->md_top = NULL;
  312         }
  313 }
  314 
  315 /*
  316  * Append a separate mbuf chain. It is caller responsibility to prevent
  317  * multiple calls to fetch/record routines.
  318  */
  319 void
  320 md_append_record(struct mdchain *mdp, struct mbuf *top)
  321 {
  322         struct mbuf *m;
  323 
  324         if (mdp->md_top == NULL) {
  325                 md_initm(mdp, top);
  326                 return;
  327         }
  328         m = mdp->md_top;
  329         while (m->m_nextpkt)
  330                 m = m->m_nextpkt;
  331         m->m_nextpkt = top;
  332         top->m_nextpkt = NULL;
  333         return;
  334 }
  335 
  336 /*
  337  * Put next record in place of existing
  338  */
  339 int
  340 md_next_record(struct mdchain *mdp)
  341 {
  342         struct mbuf *m;
  343 
  344         if (mdp->md_top == NULL)
  345                 return ENOENT;
  346         m = mdp->md_top->m_nextpkt;
  347         md_done(mdp);
  348         if (m == NULL)
  349                 return ENOENT;
  350         md_initm(mdp, m);
  351         return 0;
  352 }
  353 
  354 int
  355 md_get_uint8(struct mdchain *mdp, u_int8_t *x)
  356 {
  357         return md_get_mem(mdp, x, 1, MB_MINLINE);
  358 }
  359 
  360 int
  361 md_get_uint16(struct mdchain *mdp, u_int16_t *x)
  362 {
  363         return md_get_mem(mdp, (caddr_t)x, 2, MB_MINLINE);
  364 }
  365 
  366 int
  367 md_get_uint16le(struct mdchain *mdp, u_int16_t *x)
  368 {
  369         u_int16_t v;
  370         int error = md_get_uint16(mdp, &v);
  371 
  372         if (x != NULL)
  373                 *x = le16toh(v);
  374         return error;
  375 }
  376 
  377 int
  378 md_get_uint16be(struct mdchain *mdp, u_int16_t *x) {
  379         u_int16_t v;
  380         int error = md_get_uint16(mdp, &v);
  381 
  382         if (x != NULL)
  383                 *x = be16toh(v);
  384         return error;
  385 }
  386 
  387 int
  388 md_get_uint32(struct mdchain *mdp, u_int32_t *x)
  389 {
  390         return md_get_mem(mdp, (caddr_t)x, 4, MB_MINLINE);
  391 }
  392 
  393 int
  394 md_get_uint32be(struct mdchain *mdp, u_int32_t *x)
  395 {
  396         u_int32_t v;
  397         int error;
  398 
  399         error = md_get_uint32(mdp, &v);
  400         if (x != NULL)
  401                 *x = be32toh(v);
  402         return error;
  403 }
  404 
  405 int
  406 md_get_uint32le(struct mdchain *mdp, u_int32_t *x)
  407 {
  408         u_int32_t v;
  409         int error;
  410 
  411         error = md_get_uint32(mdp, &v);
  412         if (x != NULL)
  413                 *x = le32toh(v);
  414         return error;
  415 }
  416 
  417 int
  418 md_get_int64(struct mdchain *mdp, int64_t *x)
  419 {
  420         return md_get_mem(mdp, (caddr_t)x, 8, MB_MINLINE);
  421 }
  422 
  423 int
  424 md_get_int64be(struct mdchain *mdp, int64_t *x)
  425 {
  426         int64_t v;
  427         int error;
  428 
  429         error = md_get_int64(mdp, &v);
  430         if (x != NULL)
  431                 *x = be64toh(v);
  432         return error;
  433 }
  434 
  435 int
  436 md_get_int64le(struct mdchain *mdp, int64_t *x)
  437 {
  438         int64_t v;
  439         int error;
  440 
  441         error = md_get_int64(mdp, &v);
  442         if (x != NULL)
  443                 *x = le64toh(v);
  444         return error;
  445 }
  446 
  447 int
  448 md_get_mem(struct mdchain *mdp, caddr_t target, int size, int type)
  449 {
  450         struct mbuf *m = mdp->md_cur;
  451         int error;
  452         u_int count;
  453         u_char *s;
  454         
  455         while (size > 0) {
  456                 if (m == NULL) {
  457                         MBERROR("incomplete copy\n");
  458                         return EBADRPC;
  459                 }
  460                 s = mdp->md_pos;
  461                 count = mtod(m, u_char*) + m->m_len - s;
  462                 if (count == 0) {
  463                         mdp->md_cur = m = m->m_next;
  464                         if (m)
  465                                 s = mdp->md_pos = mtod(m, caddr_t);
  466                         continue;
  467                 }
  468                 if (count > size)
  469                         count = size;
  470                 size -= count;
  471                 mdp->md_pos += count;
  472                 if (target == NULL)
  473                         continue;
  474                 switch (type) {
  475                     case MB_MUSER:
  476                         error = copyout(s, target, count);
  477                         if (error)
  478                                 return error;
  479                         break;
  480                     case MB_MSYSTEM:
  481                         bcopy(s, target, count);
  482                         break;
  483                     case MB_MINLINE:
  484                         while (count--)
  485                                 *target++ = *s++;
  486                         continue;
  487                 }
  488                 target += count;
  489         }
  490         return 0;
  491 }
  492 
  493 int
  494 md_get_mbuf(struct mdchain *mdp, int size, struct mbuf **ret)
  495 {
  496         struct mbuf *m = mdp->md_cur, *rm;
  497 
  498         rm = m_copym(m, mdp->md_pos - mtod(m, u_char*), size, M_WAIT);
  499         md_get_mem(mdp, NULL, size, MB_MZERO);
  500         *ret = rm;
  501         return 0;
  502 }
  503 
  504 int
  505 md_get_uio(struct mdchain *mdp, struct uio *uiop, int size)
  506 {
  507         char *uiocp;
  508         long left;
  509         int mtype, error;
  510 
  511         mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
  512         while (size > 0 && uiop->uio_resid) {
  513                 if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
  514                         return EFBIG;
  515                 left = uiop->uio_iov->iov_len;
  516                 if (left == 0) {
  517                         uiop->uio_iov++;
  518                         uiop->uio_iovcnt--;
  519                         continue;
  520                 }
  521                 uiocp = uiop->uio_iov->iov_base;
  522                 if (left > size)
  523                         left = size;
  524                 error = md_get_mem(mdp, uiocp, left, mtype);
  525                 if (error)
  526                         return error;
  527                 uiop->uio_offset += left;
  528                 uiop->uio_resid -= left;
  529                 uiop->uio_iov->iov_base =
  530                     (char *)uiop->uio_iov->iov_base + left;
  531                 uiop->uio_iov->iov_len -= left;
  532                 size -= left;
  533         }
  534         return 0;
  535 }

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