bpf_buffer.c revision 331722
1/*- 2 * Copyright (c) 2007 Seccuris Inc. 3 * All rights reserved. 4 * 5 * This software was developed by Robert N. M. Watson under contract to 6 * Seccuris Inc. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 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 * Copyright (c) 1990, 1991, 1993 30 * The Regents of the University of California. All rights reserved. 31 * 32 * This code is derived from the Stanford/CMU enet packet filter, 33 * (net/enet.c) distributed as part of 4.3BSD, and code contributed 34 * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence 35 * Berkeley Laboratory. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 4. Neither the name of the University nor the names of its contributors 46 * may be used to endorse or promote products derived from this software 47 * without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 * 61 * @(#)bpf.c 8.4 (Berkeley) 1/9/95 62 */ 63 64#include <sys/cdefs.h> 65__FBSDID("$FreeBSD: stable/11/sys/net/bpf_buffer.c 331722 2018-03-29 02:50:57Z eadler $"); 66 67#include "opt_bpf.h" 68 69#include <sys/param.h> 70#include <sys/malloc.h> 71#include <sys/mbuf.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 89static int bpf_bufsize = 4096; 90SYSCTL_INT(_net_bpf, OID_AUTO, bufsize, CTLFLAG_RW, 91 &bpf_bufsize, 0, "Default capture buffer size in bytes"); 92static int bpf_maxbufsize = BPF_MAXBUFSIZE; 93SYSCTL_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 */ 99void 100bpf_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 */ 112void 113bpf_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 u_int count; 119 120 m = (struct mbuf *)src; 121 dst = (u_char *)buf + offset; 122 while (len > 0) { 123 if (m == NULL) 124 panic("bpf_mcopy"); 125 count = min(m->m_len, len); 126 bcopy(mtod(m, void *), dst, count); 127 m = m->m_next; 128 dst += count; 129 len -= count; 130 } 131} 132 133/* 134 * Free BPF kernel buffers on device close. 135 */ 136void 137bpf_buffer_free(struct bpf_d *d) 138{ 139 140 if (d->bd_sbuf != NULL) 141 free(d->bd_sbuf, M_BPF); 142 if (d->bd_hbuf != NULL) 143 free(d->bd_hbuf, M_BPF); 144 if (d->bd_fbuf != NULL) 145 free(d->bd_fbuf, M_BPF); 146 147#ifdef INVARIANTS 148 d->bd_sbuf = d->bd_hbuf = d->bd_fbuf = (caddr_t)~0; 149#endif 150} 151 152/* 153 * This is a historical initialization that occurs when the BPF descriptor is 154 * first opened. It does not imply selection of a buffer mode, so we don't 155 * allocate buffers here. 156 */ 157void 158bpf_buffer_init(struct bpf_d *d) 159{ 160 161 d->bd_bufsize = bpf_bufsize; 162} 163 164/* 165 * Allocate or resize buffers. 166 */ 167int 168bpf_buffer_ioctl_sblen(struct bpf_d *d, u_int *i) 169{ 170 u_int size; 171 caddr_t fbuf, sbuf; 172 173 size = *i; 174 if (size > bpf_maxbufsize) 175 *i = size = bpf_maxbufsize; 176 else if (size < BPF_MINBUFSIZE) 177 *i = size = BPF_MINBUFSIZE; 178 179 /* Allocate buffers immediately */ 180 fbuf = (caddr_t)malloc(size, M_BPF, M_WAITOK); 181 sbuf = (caddr_t)malloc(size, M_BPF, M_WAITOK); 182 183 BPFD_LOCK(d); 184 if (d->bd_bif != NULL) { 185 /* Interface already attached, unable to change buffers */ 186 BPFD_UNLOCK(d); 187 free(fbuf, M_BPF); 188 free(sbuf, M_BPF); 189 return (EINVAL); 190 } 191 192 /* Free old buffers if set */ 193 if (d->bd_fbuf != NULL) 194 free(d->bd_fbuf, M_BPF); 195 if (d->bd_sbuf != NULL) 196 free(d->bd_sbuf, M_BPF); 197 198 /* Fill in new data */ 199 d->bd_bufsize = size; 200 d->bd_fbuf = fbuf; 201 d->bd_sbuf = sbuf; 202 203 d->bd_hbuf = NULL; 204 d->bd_slen = 0; 205 d->bd_hlen = 0; 206 207 BPFD_UNLOCK(d); 208 return (0); 209} 210 211/* 212 * Copy buffer storage to user space in read(). 213 */ 214int 215bpf_buffer_uiomove(struct bpf_d *d, caddr_t buf, u_int len, struct uio *uio) 216{ 217 218 return (uiomove(buf, len, uio)); 219} 220