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/11.1/sys/kern/subr_mchain.c 298819 2016-04-29 22:15:33Z pfg $");
   32 
   33 #include <sys/param.h>
   34 #include <sys/systm.h>
   35 #include <sys/sysctl.h>
   36 #include <sys/endian.h>
   37 #include <sys/errno.h>
   38 #include <sys/malloc.h>
   39 #include <sys/mbuf.h>
   40 #include <sys/module.h>
   41 #include <sys/uio.h>
   42 
   43 #include <sys/mchain.h>
   44 
   45 FEATURE(libmchain, "mchain library");
   46 
   47 MODULE_VERSION(libmchain, 1);
   48 
   49 #define MBERROR(format, ...) printf("%s(%d): "format, __func__ , \
   50                                     __LINE__ , ## __VA_ARGS__)
   51 
   52 #define MBPANIC(format, ...) printf("%s(%d): "format, __func__ , \
   53                                     __LINE__ , ## __VA_ARGS__)
   54 
   55 /*
   56  * Various helper functions
   57  */
   58 int
   59 mb_init(struct mbchain *mbp)
   60 {
   61         struct mbuf *m;
   62 
   63         m = m_gethdr(M_WAITOK, MT_DATA);
   64         m->m_len = 0;
   65         mb_initm(mbp, m);
   66         return (0);
   67 }
   68 
   69 void
   70 mb_initm(struct mbchain *mbp, struct mbuf *m)
   71 {
   72         bzero(mbp, sizeof(*mbp));
   73         mbp->mb_top = mbp->mb_cur = m;
   74         mbp->mb_mleft = M_TRAILINGSPACE(m);
   75 }
   76 
   77 void
   78 mb_done(struct mbchain *mbp)
   79 {
   80         if (mbp->mb_top) {
   81                 m_freem(mbp->mb_top);
   82                 mbp->mb_top = NULL;
   83         }
   84 }
   85 
   86 struct mbuf *
   87 mb_detach(struct mbchain *mbp)
   88 {
   89         struct mbuf *m;
   90 
   91         m = mbp->mb_top;
   92         mbp->mb_top = NULL;
   93         return (m);
   94 }
   95 
   96 int
   97 mb_fixhdr(struct mbchain *mbp)
   98 {
   99         return (mbp->mb_top->m_pkthdr.len = m_fixhdr(mbp->mb_top));
  100 }
  101 
  102 /*
  103  * Check if object of size 'size' fit to the current position and
  104  * allocate new mbuf if not. Advance pointers and increase length of mbuf(s).
  105  * Return pointer to the object placeholder or NULL if any error occurred.
  106  * Note: size should be <= MLEN 
  107  */
  108 caddr_t
  109 mb_reserve(struct mbchain *mbp, int size)
  110 {
  111         struct mbuf *m, *mn;
  112         caddr_t bpos;
  113 
  114         if (size > MLEN)
  115                 panic("mb_reserve: size = %d\n", size);
  116         m = mbp->mb_cur;
  117         if (mbp->mb_mleft < size) {
  118                 mn = m_get(M_WAITOK, MT_DATA);
  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_padbyte(struct mbchain *mbp)
  133 {
  134         caddr_t dst;
  135         uint8_t x = 0;
  136 
  137         dst = mtod(mbp->mb_cur, caddr_t) + mbp->mb_cur->m_len;
  138 
  139         /* Only add padding if address is odd */
  140         if ((unsigned long)dst & 1)
  141                 return (mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM));
  142         else
  143                 return (0);
  144 }
  145 
  146 int
  147 mb_put_uint8(struct mbchain *mbp, uint8_t x)
  148 {
  149         return (mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM));
  150 }
  151 
  152 int
  153 mb_put_uint16be(struct mbchain *mbp, uint16_t x)
  154 {
  155         x = htobe16(x);
  156         return (mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM));
  157 }
  158 
  159 int
  160 mb_put_uint16le(struct mbchain *mbp, uint16_t x)
  161 {
  162         x = htole16(x);
  163         return (mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM));
  164 }
  165 
  166 int
  167 mb_put_uint32be(struct mbchain *mbp, uint32_t x)
  168 {
  169         x = htobe32(x);
  170         return (mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM));
  171 }
  172 
  173 int
  174 mb_put_uint32le(struct mbchain *mbp, uint32_t x)
  175 {
  176         x = htole32(x);
  177         return (mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM));
  178 }
  179 
  180 int
  181 mb_put_int64be(struct mbchain *mbp, int64_t x)
  182 {
  183         x = htobe64(x);
  184         return (mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM));
  185 }
  186 
  187 int
  188 mb_put_int64le(struct mbchain *mbp, int64_t x)
  189 {
  190         x = htole64(x);
  191         return (mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM));
  192 }
  193 
  194 int
  195 mb_put_mem(struct mbchain *mbp, c_caddr_t source, int size, int type)
  196 {
  197         struct mbuf *m;
  198         caddr_t dst;
  199         c_caddr_t src;
  200         int cplen, error, mleft, count;
  201         size_t srclen, dstlen;
  202 
  203         m = mbp->mb_cur;
  204         mleft = mbp->mb_mleft;
  205 
  206         while (size > 0) {
  207                 if (mleft == 0) {
  208                         if (m->m_next == NULL)
  209                                 m = m_getm(m, size, M_WAITOK, MT_DATA);
  210                         else
  211                                 m = m->m_next;
  212                         mleft = M_TRAILINGSPACE(m);
  213                         continue;
  214                 }
  215                 cplen = mleft > size ? size : mleft;
  216                 srclen = dstlen = cplen;
  217                 dst = mtod(m, caddr_t) + m->m_len;
  218                 switch (type) {
  219                     case MB_MCUSTOM:
  220                         srclen = size;
  221                         dstlen = mleft;
  222                         error = mbp->mb_copy(mbp, source, dst, &srclen, &dstlen);
  223                         if (error)
  224                                 return (error);
  225                         break;
  226                     case MB_MINLINE:
  227                         for (src = source, count = cplen; count; count--)
  228                                 *dst++ = *src++;
  229                         break;
  230                     case MB_MSYSTEM:
  231                         bcopy(source, dst, cplen);
  232                         break;
  233                     case MB_MUSER:
  234                         error = copyin(source, dst, cplen);
  235                         if (error)
  236                                 return (error);
  237                         break;
  238                     case MB_MZERO:
  239                         bzero(dst, cplen);
  240                         break;
  241                 }
  242                 size -= srclen;
  243                 source += srclen;
  244                 m->m_len += dstlen;
  245                 mleft -= dstlen;
  246                 mbp->mb_count += dstlen;
  247         }
  248         mbp->mb_cur = m;
  249         mbp->mb_mleft = mleft;
  250         return (0);
  251 }
  252 
  253 int
  254 mb_put_mbuf(struct mbchain *mbp, struct mbuf *m)
  255 {
  256         mbp->mb_cur->m_next = m;
  257         while (m) {
  258                 mbp->mb_count += m->m_len;
  259                 if (m->m_next == NULL)
  260                         break;
  261                 m = m->m_next;
  262         }
  263         mbp->mb_mleft = M_TRAILINGSPACE(m);
  264         mbp->mb_cur = m;
  265         return (0);
  266 }
  267 
  268 /*
  269  * copies a uio scatter/gather list to an mbuf chain.
  270  */
  271 int
  272 mb_put_uio(struct mbchain *mbp, struct uio *uiop, int size)
  273 {
  274         long left;
  275         int mtype, error;
  276 
  277         mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
  278 
  279         while (size > 0 && uiop->uio_resid) {
  280                 if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
  281                         return (EFBIG);
  282                 left = uiop->uio_iov->iov_len;
  283                 if (left == 0) {
  284                         uiop->uio_iov++;
  285                         uiop->uio_iovcnt--;
  286                         continue;
  287                 }
  288                 if (left > size)
  289                         left = size;
  290                 error = mb_put_mem(mbp, uiop->uio_iov->iov_base, left, mtype);
  291                 if (error)
  292                         return (error);
  293                 uiop->uio_offset += left;
  294                 uiop->uio_resid -= left;
  295                 uiop->uio_iov->iov_base =
  296                     (char *)uiop->uio_iov->iov_base + left;
  297                 uiop->uio_iov->iov_len -= left;
  298                 size -= left;
  299         }
  300         return (0);
  301 }
  302 
  303 /*
  304  * Routines for fetching data from an mbuf chain
  305  */
  306 int
  307 md_init(struct mdchain *mdp)
  308 {
  309         struct mbuf *m;
  310 
  311         m = m_gethdr(M_WAITOK, MT_DATA);
  312         m->m_len = 0;
  313         md_initm(mdp, m);
  314         return (0);
  315 }
  316 
  317 void
  318 md_initm(struct mdchain *mdp, struct mbuf *m)
  319 {
  320         bzero(mdp, sizeof(*mdp));
  321         mdp->md_top = mdp->md_cur = m;
  322         mdp->md_pos = mtod(m, u_char*);
  323 }
  324 
  325 void
  326 md_done(struct mdchain *mdp)
  327 {
  328         if (mdp->md_top) {
  329                 m_freem(mdp->md_top);
  330                 mdp->md_top = NULL;
  331         }
  332 }
  333 
  334 /*
  335  * Append a separate mbuf chain. It is caller responsibility to prevent
  336  * multiple calls to fetch/record routines.
  337  */
  338 void
  339 md_append_record(struct mdchain *mdp, struct mbuf *top)
  340 {
  341         struct mbuf *m;
  342 
  343         if (mdp->md_top == NULL) {
  344                 md_initm(mdp, top);
  345                 return;
  346         }
  347         m = mdp->md_top;
  348         while (m->m_nextpkt)
  349                 m = m->m_nextpkt;
  350         m->m_nextpkt = top;
  351         top->m_nextpkt = NULL;
  352         return;
  353 }
  354 
  355 /*
  356  * Put next record in place of existing
  357  */
  358 int
  359 md_next_record(struct mdchain *mdp)
  360 {
  361         struct mbuf *m;
  362 
  363         if (mdp->md_top == NULL)
  364                 return (ENOENT);
  365         m = mdp->md_top->m_nextpkt;
  366         md_done(mdp);
  367         if (m == NULL)
  368                 return (ENOENT);
  369         md_initm(mdp, m);
  370         return (0);
  371 }
  372 
  373 int
  374 md_get_uint8(struct mdchain *mdp, uint8_t *x)
  375 {
  376         return (md_get_mem(mdp, x, 1, MB_MINLINE));
  377 }
  378 
  379 int
  380 md_get_uint16(struct mdchain *mdp, uint16_t *x)
  381 {
  382         return (md_get_mem(mdp, (caddr_t)x, 2, MB_MINLINE));
  383 }
  384 
  385 int
  386 md_get_uint16le(struct mdchain *mdp, uint16_t *x)
  387 {
  388         uint16_t v;
  389         int error = md_get_uint16(mdp, &v);
  390 
  391         if (x != NULL)
  392                 *x = le16toh(v);
  393         return (error);
  394 }
  395 
  396 int
  397 md_get_uint16be(struct mdchain *mdp, uint16_t *x)
  398 {
  399         uint16_t v;
  400         int error = md_get_uint16(mdp, &v);
  401 
  402         if (x != NULL)
  403                 *x = be16toh(v);
  404         return (error);
  405 }
  406 
  407 int
  408 md_get_uint32(struct mdchain *mdp, uint32_t *x)
  409 {
  410         return (md_get_mem(mdp, (caddr_t)x, 4, MB_MINLINE));
  411 }
  412 
  413 int
  414 md_get_uint32be(struct mdchain *mdp, uint32_t *x)
  415 {
  416         uint32_t v;
  417         int error;
  418 
  419         error = md_get_uint32(mdp, &v);
  420         if (x != NULL)
  421                 *x = be32toh(v);
  422         return (error);
  423 }
  424 
  425 int
  426 md_get_uint32le(struct mdchain *mdp, uint32_t *x)
  427 {
  428         uint32_t v;
  429         int error;
  430 
  431         error = md_get_uint32(mdp, &v);
  432         if (x != NULL)
  433                 *x = le32toh(v);
  434         return (error);
  435 }
  436 
  437 int
  438 md_get_int64(struct mdchain *mdp, int64_t *x)
  439 {
  440         return (md_get_mem(mdp, (caddr_t)x, 8, MB_MINLINE));
  441 }
  442 
  443 int
  444 md_get_int64be(struct mdchain *mdp, int64_t *x)
  445 {
  446         int64_t v;
  447         int error;
  448 
  449         error = md_get_int64(mdp, &v);
  450         if (x != NULL)
  451                 *x = be64toh(v);
  452         return (error);
  453 }
  454 
  455 int
  456 md_get_int64le(struct mdchain *mdp, int64_t *x)
  457 {
  458         int64_t v;
  459         int error;
  460 
  461         error = md_get_int64(mdp, &v);
  462         if (x != NULL)
  463                 *x = le64toh(v);
  464         return (error);
  465 }
  466 
  467 int
  468 md_get_mem(struct mdchain *mdp, caddr_t target, int size, int type)
  469 {
  470         struct mbuf *m = mdp->md_cur;
  471         int error;
  472         u_int count;
  473         u_char *s;
  474         
  475         while (size > 0) {
  476                 if (m == NULL) {
  477                         MBERROR("incomplete copy\n");
  478                         return (EBADRPC);
  479                 }
  480                 s = mdp->md_pos;
  481                 count = mtod(m, u_char*) + m->m_len - s;
  482                 if (count == 0) {
  483                         mdp->md_cur = m = m->m_next;
  484                         if (m)
  485                                 s = mdp->md_pos = mtod(m, caddr_t);
  486                         continue;
  487                 }
  488                 if (count > size)
  489                         count = size;
  490                 size -= count;
  491                 mdp->md_pos += count;
  492                 if (target == NULL)
  493                         continue;
  494                 switch (type) {
  495                     case MB_MUSER:
  496                         error = copyout(s, target, count);
  497                         if (error)
  498                                 return error;
  499                         break;
  500                     case MB_MSYSTEM:
  501                         bcopy(s, target, count);
  502                         break;
  503                     case MB_MINLINE:
  504                         while (count--)
  505                                 *target++ = *s++;
  506                         continue;
  507                 }
  508                 target += count;
  509         }
  510         return (0);
  511 }
  512 
  513 int
  514 md_get_mbuf(struct mdchain *mdp, int size, struct mbuf **ret)
  515 {
  516         struct mbuf *m = mdp->md_cur, *rm;
  517 
  518         rm = m_copym(m, mdp->md_pos - mtod(m, u_char*), size, M_WAITOK);
  519         md_get_mem(mdp, NULL, size, MB_MZERO);
  520         *ret = rm;
  521         return (0);
  522 }
  523 
  524 int
  525 md_get_uio(struct mdchain *mdp, struct uio *uiop, int size)
  526 {
  527         char *uiocp;
  528         long left;
  529         int mtype, error;
  530 
  531         mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
  532         while (size > 0 && uiop->uio_resid) {
  533                 if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
  534                         return (EFBIG);
  535                 left = uiop->uio_iov->iov_len;
  536                 if (left == 0) {
  537                         uiop->uio_iov++;
  538                         uiop->uio_iovcnt--;
  539                         continue;
  540                 }
  541                 uiocp = uiop->uio_iov->iov_base;
  542                 if (left > size)
  543                         left = size;
  544                 error = md_get_mem(mdp, uiocp, left, mtype);
  545                 if (error)
  546                         return (error);
  547                 uiop->uio_offset += left;
  548                 uiop->uio_resid -= left;
  549                 uiop->uio_iov->iov_base =
  550                     (char *)uiop->uio_iov->iov_base + left;
  551                 uiop->uio_iov->iov_len -= left;
  552                 size -= left;
  553         }
  554         return (0);
  555 }
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FreeBSD/Linux Kernel Cross Reference sys/kern/subr_mchain.c

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