sys/opencrypto/crmbuf.c

   1 /*
   2  * Copyright (c) 2002 Somebody. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. All advertising materials mentioning features or use of this software
  13  *    must display the following acknowledgement:
  14  *      This product includes software developed by the University of
  15  *      California, Berkeley and its contributors.
  16  * 4. Neither the name of the University nor the names of its 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 REGENTS 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 REGENTS 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  * $FreeBSD: src/sys/opencrypto/crmbuf.c,v 1.1.2.1 2002/11/21 23:34:23 sam Exp $
  33  * $DragonFly: src/sys/opencrypto/crmbuf.c,v 1.2 2003/06/17 04:28:54 dillon Exp $
  34  */
  35
  36 #include "opt_param.h"
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/mbuf.h>
  40 #include <sys/kernel.h>
  41
  42 /*
  43  * Miscellaneous mbuf routines that belong in uipc_mbuf.c but
  44  * are kept private to the crypto support for now.
  45  */
  46 extern  int m_apply(struct mbuf *m, int off, int len,
  47                     int (*f)(caddr_t, caddr_t, unsigned int), caddr_t fstate);
  48 extern  struct mbuf * m_getptr(struct mbuf *m, int loc, int *off);
  49
  50 /*
  51  * Apply function f to the data in an mbuf chain starting "off" bytes from the
  52  * beginning, continuing for "len" bytes.
  53  */
  54 int
  55 m_apply(struct mbuf *m, int off, int len, int (*f)(caddr_t, caddr_t, unsigned int), caddr_t fstate)
  56 {
  57         int rval;
  58         unsigned int count;
  59
  60         if (len < 0)
  61                 panic("m_apply: len %d < 0", len);
  62         if (off < 0)
  63                 panic("m_apply: off %d < 0", off);
  64         while (off > 0) {
  65                 if (m == NULL)
  66                         panic("m_apply: null mbuf in skip");
  67                 if (off < m->m_len)
  68                         break;
  69                 off -= m->m_len;
  70                 m = m->m_next;
  71         }
  72         while (len > 0) {
  73                 if (m == NULL)
  74                         panic("m_apply: null mbuf");
  75                 count = min(m->m_len - off, len);
  76
  77                 rval = f(fstate, mtod(m, caddr_t) + off, count);
  78                 if (rval)
  79                         return (rval);
  80
  81                 len -= count;
  82                 off = 0;
  83                 m = m->m_next;
  84         }
  85
  86         return (0);
  87 }
  88
  89 /*
  90  * Return a pointer to mbuf/offset of location in mbuf chain.
  91  */
  92 struct mbuf *
  93 m_getptr(struct mbuf *m, int loc, int *off)
  94 {
  95         while (loc >= 0) {
  96                 /* Normal end of search */
  97                 if (m->m_len > loc) {
  98                         *off = loc;
  99                         return (m);
 100                 }
 101                 else {
 102                         loc -= m->m_len;
 103
 104                         if (m->m_next == NULL) {
 105                                 if (loc == 0) {
 106                                         /* Point at the end of valid data */
 107                                         *off = m->m_len;
 108                                         return (m);
 109                                 }
 110                                 else
 111                                         return (NULL);
 112                         }
 113                         else
 114                                 m = m->m_next;
 115                 }
 116         }
 117
 118         return (NULL);
 119 }