sys/net/bpf_buffer.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 2007 Seccuris Inc.
   5  * All rights reserved.
   6  *
   7  * This software was developed by Robert N. M. Watson under contract to
   8  * Seccuris Inc.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  * Copyright (c) 1990, 1991, 1993
  32  *      The Regents of the University of California.  All rights reserved.
  33  *
  34  * This code is derived from the Stanford/CMU enet packet filter,
  35  * (net/enet.c) distributed as part of 4.3BSD, and code contributed
  36  * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
  37  * Berkeley Laboratory.
  38  *
  39  * Redistribution and use in source and binary forms, with or without
  40  * modification, are permitted provided that the following conditions
  41  * are met:
  42  * 1. Redistributions of source code must retain the above copyright
  43  *    notice, this list of conditions and the following disclaimer.
  44  * 2. Redistributions in binary form must reproduce the above copyright
  45  *    notice, this list of conditions and the following disclaimer in the
  46  *    documentation and/or other materials provided with the distribution.
  47  * 3. Neither the name of the University nor the names of its contributors
  48  *    may be used to endorse or promote products derived from this software
  49  *    without specific prior written permission.
  50  *
  51  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  54  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  */
  63
  64 #include <sys/cdefs.h>
  65 #include "opt_bpf.h"
  66
  67 #include <sys/param.h>
  68 #include <sys/lock.h>
  69 #include <sys/malloc.h>
  70 #include <sys/mbuf.h>
  71 #include <sys/mutex.h>
  72 #include <sys/socket.h>
  73 #include <sys/uio.h>
  74 #include <sys/kernel.h>
  75 #include <sys/sysctl.h>
  76
  77 #include <net/if.h>
  78 #include <net/bpf.h>
  79 #include <net/bpf_buffer.h>
  80 #include <net/bpfdesc.h>
  81
  82 /*
  83  * Implement historical kernel memory buffering model for BPF: two malloc(9)
  84  * kernel buffers are hung off of the descriptor.  The size is fixed prior to
  85  * attaching to an ifnet, ad cannot be changed after that.  read(2) simply
  86  * copies the data to user space using uiomove(9).
  87  */
  88
  89 static int bpf_bufsize = 4096;
  90 SYSCTL_INT(_net_bpf, OID_AUTO, bufsize, CTLFLAG_RW,
  91     &bpf_bufsize, 0, "Default capture buffer size in bytes");
  92 static int bpf_maxbufsize = BPF_MAXBUFSIZE;
  93 SYSCTL_INT(_net_bpf, OID_AUTO, maxbufsize, CTLFLAG_RW,
  94     &bpf_maxbufsize, 0, "Maximum capture buffer in bytes");
  95
  96 /*
  97  * Simple data copy to the current kernel buffer.
  98  */
  99 void
 100 bpf_buffer_append_bytes(struct bpf_d *d, caddr_t buf, u_int offset,
 101     void *src, u_int len)
 102 {
 103         u_char *src_bytes;
 104
 105         src_bytes = (u_char *)src;
 106         bcopy(src_bytes, buf + offset, len);
 107 }
 108
 109 /*
 110  * Scatter-gather data copy from an mbuf chain to the current kernel buffer.
 111  */
 112 void
 113 bpf_buffer_append_mbuf(struct bpf_d *d, caddr_t buf, u_int offset, void *src,
 114     u_int len)
 115 {
 116         const struct mbuf *m;
 117         u_char *dst;
 118
 119         m = (struct mbuf *)src;
 120         dst = (u_char *)buf + offset;
 121         m_copydata(m, 0, len, dst);
 122 }
 123
 124 /*
 125  * Free BPF kernel buffers on device close.
 126  */
 127 void
 128 bpf_buffer_free(struct bpf_d *d)
 129 {
 130
 131         if (d->bd_sbuf != NULL)
 132                 free(d->bd_sbuf, M_BPF);
 133         if (d->bd_hbuf != NULL)
 134                 free(d->bd_hbuf, M_BPF);
 135         if (d->bd_fbuf != NULL)
 136                 free(d->bd_fbuf, M_BPF);
 137
 138 #ifdef INVARIANTS
 139         d->bd_sbuf = d->bd_hbuf = d->bd_fbuf = (caddr_t)~0;
 140 #endif
 141 }
 142
 143 /*
 144  * This is a historical initialization that occurs when the BPF descriptor is
 145  * first opened.  It does not imply selection of a buffer mode, so we don't
 146  * allocate buffers here.
 147  */
 148 void
 149 bpf_buffer_init(struct bpf_d *d)
 150 {
 151
 152         d->bd_bufsize = bpf_bufsize;
 153 }
 154
 155 /*
 156  * Allocate or resize buffers.
 157  */
 158 int
 159 bpf_buffer_ioctl_sblen(struct bpf_d *d, u_int *i)
 160 {
 161         u_int size;
 162         caddr_t fbuf, sbuf;
 163
 164         size = *i;
 165         if (size > bpf_maxbufsize)
 166                 *i = size = bpf_maxbufsize;
 167         else if (size < BPF_MINBUFSIZE)
 168                 *i = size = BPF_MINBUFSIZE;
 169
 170         /* Allocate buffers immediately */
 171         fbuf = (caddr_t)malloc(size, M_BPF, M_WAITOK);
 172         sbuf = (caddr_t)malloc(size, M_BPF, M_WAITOK);
 173
 174         BPFD_LOCK(d);
 175         if (d->bd_bif != NULL) {
 176                 /* Interface already attached, unable to change buffers */
 177                 BPFD_UNLOCK(d);
 178                 free(fbuf, M_BPF);
 179                 free(sbuf, M_BPF);
 180                 return (EINVAL);
 181         }
 182
 183         /* Free old buffers if set */
 184         if (d->bd_fbuf != NULL)
 185                 free(d->bd_fbuf, M_BPF);
 186         if (d->bd_sbuf != NULL)
 187                 free(d->bd_sbuf, M_BPF);
 188
 189         /* Fill in new data */
 190         d->bd_bufsize = size;
 191         d->bd_fbuf = fbuf;
 192         d->bd_sbuf = sbuf;
 193
 194         d->bd_hbuf = NULL;
 195         d->bd_slen = 0;
 196         d->bd_hlen = 0;
 197
 198         BPFD_UNLOCK(d);
 199         return (0);
 200 }
 201
 202 /*
 203  * Copy buffer storage to user space in read().
 204  */
 205 int
 206 bpf_buffer_uiomove(struct bpf_d *d, caddr_t buf, u_int len, struct uio *uio)
 207 {
 208
 209         return (uiomove(buf, len, uio));
 210 }