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/6.3/sys/kern/subr_mchain.c 173886 2007-11-24 19:45:58Z cvs2svn $");
   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_TRYWAIT, MT_DATA);
   60         if (m == NULL) 
   61                 return ENOBUFS;
   62         m->m_len = 0;
   63         mb_initm(mbp, m);
   64         return 0;
   65 }
   66 
   67 void
   68 mb_initm(struct mbchain *mbp, struct mbuf *m)
   69 {
   70         bzero(mbp, sizeof(*mbp));
   71         mbp->mb_top = mbp->mb_cur = m;
   72         mbp->mb_mleft = M_TRAILINGSPACE(m);
   73 }
   74 
   75 void
   76 mb_done(struct mbchain *mbp)
   77 {
   78         if (mbp->mb_top) {
   79                 m_freem(mbp->mb_top);
   80                 mbp->mb_top = NULL;
   81         }
   82 }
   83 
   84 struct mbuf *
   85 mb_detach(struct mbchain *mbp)
   86 {
   87         struct mbuf *m;
   88 
   89         m = mbp->mb_top;
   90         mbp->mb_top = NULL;
   91         return m;
   92 }
   93 
   94 int
   95 mb_fixhdr(struct mbchain *mbp)
   96 {
   97         return mbp->mb_top->m_pkthdr.len = m_fixhdr(mbp->mb_top);
   98 }
   99 
  100 /*
  101  * Check if object of size 'size' fit to the current position and
  102  * allocate new mbuf if not. Advance pointers and increase length of mbuf(s).
  103  * Return pointer to the object placeholder or NULL if any error occured.
  104  * Note: size should be <= MLEN 
  105  */
  106 caddr_t
  107 mb_reserve(struct mbchain *mbp, int size)
  108 {
  109         struct mbuf *m, *mn;
  110         caddr_t bpos;
  111 
  112         if (size > MLEN)
  113                 panic("mb_reserve: size = %d\n", size);
  114         m = mbp->mb_cur;
  115         if (mbp->mb_mleft < size) {
  116                 mn = m_get(M_TRYWAIT, MT_DATA);
  117                 if (mn == NULL)
  118                         return NULL;
  119                 mbp->mb_cur = m->m_next = mn;
  120                 m = mn;
  121                 m->m_len = 0;
  122                 mbp->mb_mleft = M_TRAILINGSPACE(m);
  123         }
  124         mbp->mb_mleft -= size;
  125         mbp->mb_count += size;
  126         bpos = mtod(m, caddr_t) + m->m_len;
  127         m->m_len += size;
  128         return bpos;
  129 }
  130 
  131 int
  132 mb_put_uint8(struct mbchain *mbp, u_int8_t x)
  133 {
  134         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  135 }
  136 
  137 int
  138 mb_put_uint16be(struct mbchain *mbp, u_int16_t x)
  139 {
  140         x = htobe16(x);
  141         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  142 }
  143 
  144 int
  145 mb_put_uint16le(struct mbchain *mbp, u_int16_t x)
  146 {
  147         x = htole16(x);
  148         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  149 }
  150 
  151 int
  152 mb_put_uint32be(struct mbchain *mbp, u_int32_t x)
  153 {
  154         x = htobe32(x);
  155         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  156 }
  157 
  158 int
  159 mb_put_uint32le(struct mbchain *mbp, u_int32_t x)
  160 {
  161         x = htole32(x);
  162         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  163 }
  164 
  165 int
  166 mb_put_int64be(struct mbchain *mbp, int64_t x)
  167 {
  168         x = htobe64(x);
  169         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  170 }
  171 
  172 int
  173 mb_put_int64le(struct mbchain *mbp, int64_t x)
  174 {
  175         x = htole64(x);
  176         return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
  177 }
  178 
  179 int
  180 mb_put_mem(struct mbchain *mbp, c_caddr_t source, int size, int type)
  181 {
  182         struct mbuf *m;
  183         caddr_t dst;
  184         c_caddr_t src;
  185         int cplen, error, mleft, count;
  186 
  187         m = mbp->mb_cur;
  188         mleft = mbp->mb_mleft;
  189 
  190         while (size > 0) {
  191                 if (mleft == 0) {
  192                         if (m->m_next == NULL) {
  193                                 m = m_getm(m, size, M_TRYWAIT, MT_DATA);
  194                                 if (m == NULL)
  195                                         return ENOBUFS;
  196                         } else
  197                                 m = m->m_next;
  198                         mleft = M_TRAILINGSPACE(m);
  199                         continue;
  200                 }
  201                 cplen = mleft > size ? size : mleft;
  202                 dst = mtod(m, caddr_t) + m->m_len;
  203                 switch (type) {
  204                     case MB_MCUSTOM:
  205                         error = mbp->mb_copy(mbp, source, dst, cplen);
  206                         if (error)
  207                                 return error;
  208                         break;
  209                     case MB_MINLINE:
  210                         for (src = source, count = cplen; count; count--)
  211                                 *dst++ = *src++;
  212                         break;
  213                     case MB_MSYSTEM:
  214                         bcopy(source, dst, cplen);
  215                         break;
  216                     case MB_MUSER:
  217                         error = copyin(source, dst, cplen);
  218                         if (error)
  219                                 return error;
  220                         break;
  221                     case MB_MZERO:
  222                         bzero(dst, cplen);
  223                         break;
  224                 }
  225                 size -= cplen;
  226                 source += cplen;
  227                 m->m_len += cplen;
  228                 mleft -= cplen;
  229                 mbp->mb_count += cplen;
  230         }
  231         mbp->mb_cur = m;
  232         mbp->mb_mleft = mleft;
  233         return 0;
  234 }
  235 
  236 int
  237 mb_put_mbuf(struct mbchain *mbp, struct mbuf *m)
  238 {
  239         mbp->mb_cur->m_next = m;
  240         while (m) {
  241                 mbp->mb_count += m->m_len;
  242                 if (m->m_next == NULL)
  243                         break;
  244                 m = m->m_next;
  245         }
  246         mbp->mb_mleft = M_TRAILINGSPACE(m);
  247         mbp->mb_cur = m;
  248         return 0;
  249 }
  250 
  251 /*
  252  * copies a uio scatter/gather list to an mbuf chain.
  253  */
  254 int
  255 mb_put_uio(struct mbchain *mbp, struct uio *uiop, int size)
  256 {
  257         long left;
  258         int mtype, error;
  259 
  260         mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
  261 
  262         while (size > 0 && uiop->uio_resid) {
  263                 if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
  264                         return EFBIG;
  265                 left = uiop->uio_iov->iov_len;
  266                 if (left == 0) {
  267                         uiop->uio_iov++;
  268                         uiop->uio_iovcnt--;
  269                         continue;
  270                 }
  271                 if (left > size)
  272                         left = size;
  273                 error = mb_put_mem(mbp, uiop->uio_iov->iov_base, left, mtype);
  274                 if (error)
  275                         return error;
  276                 uiop->uio_offset += left;
  277                 uiop->uio_resid -= left;
  278                 uiop->uio_iov->iov_base =
  279                     (char *)uiop->uio_iov->iov_base + left;
  280                 uiop->uio_iov->iov_len -= left;
  281                 size -= left;
  282         }
  283         return 0;
  284 }
  285 
  286 /*
  287  * Routines for fetching data from an mbuf chain
  288  */
  289 int
  290 md_init(struct mdchain *mdp)
  291 {
  292         struct mbuf *m;
  293 
  294         m = m_gethdr(M_TRYWAIT, MT_DATA);
  295         if (m == NULL) 
  296                 return ENOBUFS;
  297         m->m_len = 0;
  298         md_initm(mdp, m);
  299         return 0;
  300 }
  301 
  302 void
  303 md_initm(struct mdchain *mdp, struct mbuf *m)
  304 {
  305         bzero(mdp, sizeof(*mdp));
  306         mdp->md_top = mdp->md_cur = m;
  307         mdp->md_pos = mtod(m, u_char*);
  308 }
  309 
  310 void
  311 md_done(struct mdchain *mdp)
  312 {
  313         if (mdp->md_top) {
  314                 m_freem(mdp->md_top);
  315                 mdp->md_top = NULL;
  316         }
  317 }
  318 
  319 /*
  320  * Append a separate mbuf chain. It is caller responsibility to prevent
  321  * multiple calls to fetch/record routines.
  322  */
  323 void
  324 md_append_record(struct mdchain *mdp, struct mbuf *top)
  325 {
  326         struct mbuf *m;
  327 
  328         if (mdp->md_top == NULL) {
  329                 md_initm(mdp, top);
  330                 return;
  331         }
  332         m = mdp->md_top;
  333         while (m->m_nextpkt)
  334                 m = m->m_nextpkt;
  335         m->m_nextpkt = top;
  336         top->m_nextpkt = NULL;
  337         return;
  338 }
  339 
  340 /*
  341  * Put next record in place of existing
  342  */
  343 int
  344 md_next_record(struct mdchain *mdp)
  345 {
  346         struct mbuf *m;
  347 
  348         if (mdp->md_top == NULL)
  349                 return ENOENT;
  350         m = mdp->md_top->m_nextpkt;
  351         md_done(mdp);
  352         if (m == NULL)
  353                 return ENOENT;
  354         md_initm(mdp, m);
  355         return 0;
  356 }
  357 
  358 int
  359 md_get_uint8(struct mdchain *mdp, u_int8_t *x)
  360 {
  361         return md_get_mem(mdp, x, 1, MB_MINLINE);
  362 }
  363 
  364 int
  365 md_get_uint16(struct mdchain *mdp, u_int16_t *x)
  366 {
  367         return md_get_mem(mdp, (caddr_t)x, 2, MB_MINLINE);
  368 }
  369 
  370 int
  371 md_get_uint16le(struct mdchain *mdp, u_int16_t *x)
  372 {
  373         u_int16_t v;
  374         int error = md_get_uint16(mdp, &v);
  375 
  376         if (x != NULL)
  377                 *x = le16toh(v);
  378         return error;
  379 }
  380 
  381 int
  382 md_get_uint16be(struct mdchain *mdp, u_int16_t *x) {
  383         u_int16_t v;
  384         int error = md_get_uint16(mdp, &v);
  385 
  386         if (x != NULL)
  387                 *x = be16toh(v);
  388         return error;
  389 }
  390 
  391 int
  392 md_get_uint32(struct mdchain *mdp, u_int32_t *x)
  393 {
  394         return md_get_mem(mdp, (caddr_t)x, 4, MB_MINLINE);
  395 }
  396 
  397 int
  398 md_get_uint32be(struct mdchain *mdp, u_int32_t *x)
  399 {
  400         u_int32_t v;
  401         int error;
  402 
  403         error = md_get_uint32(mdp, &v);
  404         if (x != NULL)
  405                 *x = be32toh(v);
  406         return error;
  407 }
  408 
  409 int
  410 md_get_uint32le(struct mdchain *mdp, u_int32_t *x)
  411 {
  412         u_int32_t v;
  413         int error;
  414 
  415         error = md_get_uint32(mdp, &v);
  416         if (x != NULL)
  417                 *x = le32toh(v);
  418         return error;
  419 }
  420 
  421 int
  422 md_get_int64(struct mdchain *mdp, int64_t *x)
  423 {
  424         return md_get_mem(mdp, (caddr_t)x, 8, MB_MINLINE);
  425 }
  426 
  427 int
  428 md_get_int64be(struct mdchain *mdp, int64_t *x)
  429 {
  430         int64_t v;
  431         int error;
  432 
  433         error = md_get_int64(mdp, &v);
  434         if (x != NULL)
  435                 *x = be64toh(v);
  436         return error;
  437 }
  438 
  439 int
  440 md_get_int64le(struct mdchain *mdp, int64_t *x)
  441 {
  442         int64_t v;
  443         int error;
  444 
  445         error = md_get_int64(mdp, &v);
  446         if (x != NULL)
  447                 *x = le64toh(v);
  448         return error;
  449 }
  450 
  451 int
  452 md_get_mem(struct mdchain *mdp, caddr_t target, int size, int type)
  453 {
  454         struct mbuf *m = mdp->md_cur;
  455         int error;
  456         u_int count;
  457         u_char *s;
  458         
  459         while (size > 0) {
  460                 if (m == NULL) {
  461                         MBERROR("incomplete copy\n");
  462                         return EBADRPC;
  463                 }
  464                 s = mdp->md_pos;
  465                 count = mtod(m, u_char*) + m->m_len - s;
  466                 if (count == 0) {
  467                         mdp->md_cur = m = m->m_next;
  468                         if (m)
  469                                 s = mdp->md_pos = mtod(m, caddr_t);
  470                         continue;
  471                 }
  472                 if (count > size)
  473                         count = size;
  474                 size -= count;
  475                 mdp->md_pos += count;
  476                 if (target == NULL)
  477                         continue;
  478                 switch (type) {
  479                     case MB_MUSER:
  480                         error = copyout(s, target, count);
  481                         if (error)
  482                                 return error;
  483                         break;
  484                     case MB_MSYSTEM:
  485                         bcopy(s, target, count);
  486                         break;
  487                     case MB_MINLINE:
  488                         while (count--)
  489                                 *target++ = *s++;
  490                         continue;
  491                 }
  492                 target += count;
  493         }
  494         return 0;
  495 }
  496 
  497 int
  498 md_get_mbuf(struct mdchain *mdp, int size, struct mbuf **ret)
  499 {
  500         struct mbuf *m = mdp->md_cur, *rm;
  501 
  502         rm = m_copym(m, mdp->md_pos - mtod(m, u_char*), size, M_TRYWAIT);
  503         if (rm == NULL)
  504                 return EBADRPC;
  505         md_get_mem(mdp, NULL, size, MB_MZERO);
  506         *ret = rm;
  507         return 0;
  508 }
  509 
  510 int
  511 md_get_uio(struct mdchain *mdp, struct uio *uiop, int size)
  512 {
  513         char *uiocp;
  514         long left;
  515         int mtype, error;
  516 
  517         mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
  518         while (size > 0 && uiop->uio_resid) {
  519                 if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
  520                         return EFBIG;
  521                 left = uiop->uio_iov->iov_len;
  522                 if (left == 0) {
  523                         uiop->uio_iov++;
  524                         uiop->uio_iovcnt--;
  525                         continue;
  526                 }
  527                 uiocp = uiop->uio_iov->iov_base;
  528                 if (left > size)
  529                         left = size;
  530                 error = md_get_mem(mdp, uiocp, left, mtype);
  531                 if (error)
  532                         return error;
  533                 uiop->uio_offset += left;
  534                 uiop->uio_resid -= left;
  535                 uiop->uio_iov->iov_base =
  536                     (char *)uiop->uio_iov->iov_base + left;
  537                 uiop->uio_iov->iov_len -= left;
  538                 size -= left;
  539         }
  540         return 0;
  541 }

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