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  * 3. All advertising materials mentioning features or use of this software
   14  *    must display the following acknowledgement:
   15  *    This product includes software developed by Boris Popov.
   16  * 4. Neither the name of the author nor the names of any co-contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  */
   32 
   33 #include <sys/cdefs.h>
   34 __FBSDID("$FreeBSD$");
   35 
   36 #include <sys/param.h>
   37 #include <sys/systm.h>
   38 #include <sys/kernel.h>
   39 #include <sys/endian.h>
   40 #include <sys/errno.h>
   41 #include <sys/malloc.h>
   42 #include <sys/mbuf.h>
   43 #include <sys/module.h>
   44 #include <sys/uio.h>
   45 
   46 #include <sys/mchain.h>
   47 
   48 MODULE_VERSION(libmchain, 1);
   49 
   50 #define MBERROR(format, args...) printf("%s(%d): "format, __func__ , \
   51                                     __LINE__ , ## args)
   52 
   53 #define MBPANIC(format, args...) printf("%s(%d): "format, __func__ , \
   54                                     __LINE__ , ## args)
   55 
   56 int
   57 mb_init(struct mbchain *mbp)
   58 {
   59         struct mbuf *m;
   60 
   61         m = m_gethdr(M_WAITOK, MT_DATA);
   62         if (m == NULL) 
   63                 return ENOBUFS;
   64         m->m_pkthdr.rcvif = NULL;
   65         m->m_len = 0;
   66         mb_initm(mbp, m);
   67         return 0;
   68 }
   69 
   70 void
   71 mb_initm(struct mbchain *mbp, struct mbuf *m)
   72 {
   73         bzero(mbp, sizeof(*mbp));
   74         mbp->mb_top = mbp->mb_cur = m;
   75         mbp->mb_mleft = M_TRAILINGSPACE(m);
   76 }
   77 
   78 void
   79 mb_done(struct mbchain *mbp)
   80 {
   81         if (mbp->mb_top) {
   82                 m_freem(mbp->mb_top);
   83                 mbp->mb_top = NULL;
   84         }
   85 }
   86 
   87 struct mbuf *
   88 mb_detach(struct mbchain *mbp)
   89 {
   90         struct mbuf *m;
   91 
   92         m = mbp->mb_top;
   93         mbp->mb_top = NULL;
   94         return m;
   95 }
   96 
   97 int
   98 mb_fixhdr(struct mbchain *mbp)
   99 {
  100         return mbp->mb_top->m_pkthdr.len = m_fixhdr(mbp->mb_top);
  101 }
  102 
  103 /*
  104  * Check if object of size 'size' fit to the current position and
  105  * allocate new mbuf if not. Advance pointers and increase length of mbuf(s).
  106  * Return pointer to the object placeholder or NULL if any error occured.
  107  * Note: size should be <= MLEN 
  108  */
  109 caddr_t
  110 mb_reserve(struct mbchain *mbp, int size)
  111 {
  112         struct mbuf *m, *mn;
  113         caddr_t bpos;
  114 
  115         if (size > MLEN)
  116                 panic("mb_reserve: size = %d\n", size);
  117         m = mbp->mb_cur;
  118         if (mbp->mb_mleft < size) {
  119                 mn = m_get(M_WAITOK, MT_DATA);
  120                 if (mn == NULL)
  121                         return NULL;
  122                 mbp->mb_cur = m->m_next = mn;
  123                 m = mn;
  124                 m->m_len = 0;
  125                 mbp->mb_mleft = M_TRAILINGSPACE(m);
  126         }
  127         mbp->mb_mleft -= size;
  128         mbp->mb_count += size;
  129         bpos = mtod(m, caddr_t) + m->m_len;
  130         m->m_len += size;
  131         return bpos;
  132 }
  133 
  134 int
  135 mb_put_uint8(struct mbchain *mbp, u_int8_t x)
  136 {
  137         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  138 }
  139 
  140 int
  141 mb_put_uint16be(struct mbchain *mbp, u_int16_t x)
  142 {
  143         x = htobe16(x);
  144         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  145 }
  146 
  147 int
  148 mb_put_uint16le(struct mbchain *mbp, u_int16_t x)
  149 {
  150         x = htole16(x);
  151         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  152 }
  153 
  154 int
  155 mb_put_uint32be(struct mbchain *mbp, u_int32_t x)
  156 {
  157         x = htobe32(x);
  158         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  159 }
  160 
  161 int
  162 mb_put_uint32le(struct mbchain *mbp, u_int32_t x)
  163 {
  164         x = htole32(x);
  165         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  166 }
  167 
  168 int
  169 mb_put_int64be(struct mbchain *mbp, int64_t x)
  170 {
  171 #if xxx
  172         x = htobe64(x);
  173 #else
  174         x = htobeq(x);
  175 #endif
  176         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  177 }
  178 
  179 int
  180 mb_put_int64le(struct mbchain *mbp, int64_t x)
  181 {
  182         x = htole64(x);
  183         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  184 }
  185 
  186 int
  187 mb_put_mem(struct mbchain *mbp, c_caddr_t source, int size, int type)
  188 {
  189         struct mbuf *m;
  190         caddr_t dst;
  191         c_caddr_t src;
  192         int cplen, error, mleft, count;
  193 
  194         m = mbp->mb_cur;
  195         mleft = mbp->mb_mleft;
  196 
  197         while (size > 0) {
  198                 if (mleft == 0) {
  199                         if (m->m_next == NULL) {
  200                                 m = m_getm(m, size, M_WAITOK, MT_DATA);
  201                                 if (m == NULL)
  202                                         return ENOBUFS;
  203                         }
  204                         m = m->m_next;
  205                         mleft = M_TRAILINGSPACE(m);
  206                         continue;
  207                 }
  208                 cplen = mleft > size ? size : mleft;
  209                 dst = mtod(m, caddr_t) + m->m_len;
  210                 switch (type) {
  211                     case MB_MCUSTOM:
  212                         error = mbp->mb_copy(mbp, source, dst, cplen);
  213                         if (error)
  214                                 return error;
  215                         break;
  216                     case MB_MINLINE:
  217                         for (src = source, count = cplen; count; count--)
  218                                 *dst++ = *src++;
  219                         break;
  220                     case MB_MSYSTEM:
  221                         bcopy(source, dst, cplen);
  222                         break;
  223                     case MB_MUSER:
  224                         error = copyin(source, dst, cplen);
  225                         if (error)
  226                                 return error;
  227                         break;
  228                     case MB_MZERO:
  229                         bzero(dst, cplen);
  230                         break;
  231                 }
  232                 size -= cplen;
  233                 source += cplen;
  234                 m->m_len += cplen;
  235                 mleft -= cplen;
  236                 mbp->mb_count += cplen;
  237         }
  238         mbp->mb_cur = m;
  239         mbp->mb_mleft = mleft;
  240         return 0;
  241 }
  242 
  243 int
  244 mb_put_mbuf(struct mbchain *mbp, struct mbuf *m)
  245 {
  246         mbp->mb_cur->m_next = m;
  247         while (m) {
  248                 mbp->mb_count += m->m_len;
  249                 if (m->m_next == NULL)
  250                         break;
  251                 m = m->m_next;
  252         }
  253         mbp->mb_mleft = M_TRAILINGSPACE(m);
  254         mbp->mb_cur = m;
  255         return 0;
  256 }
  257 
  258 /*
  259  * copies a uio scatter/gather list to an mbuf chain.
  260  */
  261 int
  262 mb_put_uio(struct mbchain *mbp, struct uio *uiop, int size)
  263 {
  264         long left;
  265         int mtype, error;
  266 
  267         mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
  268 
  269         while (size > 0 && uiop->uio_resid) {
  270                 if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
  271                         return EFBIG;
  272                 left = uiop->uio_iov->iov_len;
  273                 if (left == 0) {
  274                         uiop->uio_iov++;
  275                         uiop->uio_iovcnt--;
  276                         continue;
  277                 }
  278                 if (left > size)
  279                         left = size;
  280                 error = mb_put_mem(mbp, uiop->uio_iov->iov_base, left, mtype);
  281                 if (error)
  282                         return error;
  283                 uiop->uio_offset += left;
  284                 uiop->uio_resid -= left;
  285                 uiop->uio_iov->iov_base += left;
  286                 uiop->uio_iov->iov_len -= left;
  287                 size -= left;
  288         }
  289         return 0;
  290 }
  291 
  292 /*
  293  * Routines for fetching data from an mbuf chain
  294  */
  295 int
  296 md_init(struct mdchain *mdp)
  297 {
  298         struct mbuf *m;
  299 
  300         m = m_gethdr(M_WAITOK, MT_DATA);
  301         if (m == NULL) 
  302                 return ENOBUFS;
  303         m->m_pkthdr.rcvif = NULL;
  304         m->m_len = 0;
  305         md_initm(mdp, m);
  306         return 0;
  307 }
  308 
  309 void
  310 md_initm(struct mdchain *mdp, struct mbuf *m)
  311 {
  312         bzero(mdp, sizeof(*mdp));
  313         mdp->md_top = mdp->md_cur = m;
  314         mdp->md_pos = mtod(m, u_char*);
  315 }
  316 
  317 void
  318 md_done(struct mdchain *mdp)
  319 {
  320         if (mdp->md_top) {
  321                 m_freem(mdp->md_top);
  322                 mdp->md_top = NULL;
  323         }
  324 }
  325 
  326 /*
  327  * Append a separate mbuf chain. It is caller responsibility to prevent
  328  * multiple calls to fetch/record routines.
  329  */
  330 void
  331 md_append_record(struct mdchain *mdp, struct mbuf *top)
  332 {
  333         struct mbuf *m;
  334 
  335         if (mdp->md_top == NULL) {
  336                 md_initm(mdp, top);
  337                 return;
  338         }
  339         m = mdp->md_top;
  340         while (m->m_nextpkt)
  341                 m = m->m_nextpkt;
  342         m->m_nextpkt = top;
  343         top->m_nextpkt = NULL;
  344         return;
  345 }
  346 
  347 /*
  348  * Put next record in place of existing
  349  */
  350 int
  351 md_next_record(struct mdchain *mdp)
  352 {
  353         struct mbuf *m;
  354 
  355         if (mdp->md_top == NULL)
  356                 return ENOENT;
  357         m = mdp->md_top->m_nextpkt;
  358         md_done(mdp);
  359         if (m == NULL)
  360                 return ENOENT;
  361         md_initm(mdp, m);
  362         return 0;
  363 }
  364 
  365 int
  366 md_get_uint8(struct mdchain *mdp, u_int8_t *x)
  367 {
  368         return md_get_mem(mdp, x, 1, MB_MINLINE);
  369 }
  370 
  371 int
  372 md_get_uint16(struct mdchain *mdp, u_int16_t *x)
  373 {
  374         return md_get_mem(mdp, (caddr_t)x, 2, MB_MINLINE);
  375 }
  376 
  377 int
  378 md_get_uint16le(struct mdchain *mdp, u_int16_t *x)
  379 {
  380         u_int16_t v;
  381         int error = md_get_uint16(mdp, &v);
  382 
  383         if (x != NULL)
  384                 *x = le16toh(v);
  385         return error;
  386 }
  387 
  388 int
  389 md_get_uint16be(struct mdchain *mdp, u_int16_t *x) {
  390         u_int16_t v;
  391         int error = md_get_uint16(mdp, &v);
  392 
  393         if (x != NULL)
  394                 *x = be16toh(v);
  395         return error;
  396 }
  397 
  398 int
  399 md_get_uint32(struct mdchain *mdp, u_int32_t *x)
  400 {
  401         return md_get_mem(mdp, (caddr_t)x, 4, MB_MINLINE);
  402 }
  403 
  404 int
  405 md_get_uint32be(struct mdchain *mdp, u_int32_t *x)
  406 {
  407         u_int32_t v;
  408         int error;
  409 
  410         error = md_get_uint32(mdp, &v);
  411         if (x != NULL)
  412                 *x = be32toh(v);
  413         return error;
  414 }
  415 
  416 int
  417 md_get_uint32le(struct mdchain *mdp, u_int32_t *x)
  418 {
  419         u_int32_t v;
  420         int error;
  421 
  422         error = md_get_uint32(mdp, &v);
  423         if (x != NULL)
  424                 *x = le32toh(v);
  425         return error;
  426 }
  427 
  428 int
  429 md_get_int64(struct mdchain *mdp, int64_t *x)
  430 {
  431         return md_get_mem(mdp, (caddr_t)x, 8, MB_MINLINE);
  432 }
  433 
  434 int
  435 md_get_int64be(struct mdchain *mdp, int64_t *x)
  436 {
  437         int64_t v;
  438         int error;
  439 
  440         error = md_get_int64(mdp, &v);
  441         if (x != NULL)
  442 #if xxx
  443                 *x = be64toh(v);
  444 #else
  445                 *x = betohq(v);
  446 #endif
  447         return error;
  448 }
  449 
  450 int
  451 md_get_int64le(struct mdchain *mdp, int64_t *x)
  452 {
  453         int64_t v;
  454         int error;
  455 
  456         error = md_get_int64(mdp, &v);
  457         if (x != NULL)
  458                 *x = le64toh(v);
  459         return error;
  460 }
  461 
  462 int
  463 md_get_mem(struct mdchain *mdp, caddr_t target, int size, int type)
  464 {
  465         struct mbuf *m = mdp->md_cur;
  466         int error;
  467         u_int count;
  468         u_char *s;
  469         
  470         while (size > 0) {
  471                 if (m == NULL) {
  472                         MBERROR("incomplete copy\n");
  473                         return EBADRPC;
  474                 }
  475                 s = mdp->md_pos;
  476                 count = mtod(m, u_char*) + m->m_len - s;
  477                 if (count == 0) {
  478                         mdp->md_cur = m = m->m_next;
  479                         if (m)
  480                                 s = mdp->md_pos = mtod(m, caddr_t);
  481                         continue;
  482                 }
  483                 if (count > size)
  484                         count = size;
  485                 size -= count;
  486                 mdp->md_pos += count;
  487                 if (target == NULL)
  488                         continue;
  489                 switch (type) {
  490                     case MB_MUSER:
  491                         error = copyout(s, target, count);
  492                         if (error)
  493                                 return error;
  494                         break;
  495                     case MB_MSYSTEM:
  496                         bcopy(s, target, count);
  497                         break;
  498                     case MB_MINLINE:
  499                         while (count--)
  500                                 *target++ = *s++;
  501                         continue;
  502                 }
  503                 target += count;
  504         }
  505         return 0;
  506 }
  507 
  508 int
  509 md_get_mbuf(struct mdchain *mdp, int size, struct mbuf **ret)
  510 {
  511         struct mbuf *m = mdp->md_cur, *rm;
  512 
  513         rm = m_copym(m, mdp->md_pos - mtod(m, u_char*), size, M_WAITOK);
  514         if (rm == NULL)
  515                 return EBADRPC;
  516         md_get_mem(mdp, NULL, size, MB_MZERO);
  517         *ret = rm;
  518         return 0;
  519 }
  520 
  521 int
  522 md_get_uio(struct mdchain *mdp, struct uio *uiop, int size)
  523 {
  524         char *uiocp;
  525         long left;
  526         int mtype, error;
  527 
  528         mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
  529         while (size > 0 && uiop->uio_resid) {
  530                 if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
  531                         return EFBIG;
  532                 left = uiop->uio_iov->iov_len;
  533                 if (left == 0) {
  534                         uiop->uio_iov++;
  535                         uiop->uio_iovcnt--;
  536                         continue;
  537                 }
  538                 uiocp = uiop->uio_iov->iov_base;
  539                 if (left > size)
  540                         left = size;
  541                 error = md_get_mem(mdp, uiocp, left, mtype);
  542                 if (error)
  543                         return error;
  544                 uiop->uio_offset += left;
  545                 uiop->uio_resid -= left;
  546                 uiop->uio_iov->iov_base += left;
  547                 uiop->uio_iov->iov_len -= left;
  548                 size -= left;
  549         }
  550         return 0;
  551 }

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