bpf_buffer.c revision 177585
1/*- 2 * Copyright (c) 2007 Seccuris Inc. 3 * All rights reserved. 4 * 5 * This sofware 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: head/sys/net/bpf_buffer.c 177585 2008-03-24 22:21:32Z jkim $"); 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/bpf_jitter.h> 81#include <net/bpfdesc.h> 82 83/* 84 * Implement historical kernel memory buffering model for BPF: two malloc(9) 85 * kernel buffers are hung off of the descriptor. The size is fixed prior to 86 * attaching to an ifnet, ad cannot be changed after that. read(2) simply 87 * copies the data to user space using uiomove(9). 88 */ 89 90static int bpf_bufsize = 4096; 91SYSCTL_INT(_net_bpf, OID_AUTO, bufsize, CTLFLAG_RW, 92 &bpf_bufsize, 0, ""); 93static int bpf_maxbufsize = BPF_MAXBUFSIZE; 94SYSCTL_INT(_net_bpf, OID_AUTO, maxbufsize, CTLFLAG_RW, 95 &bpf_maxbufsize, 0, ""); 96 97void 98bpf_buffer_alloc(struct bpf_d *d) 99{ 100 101 KASSERT(d->bd_fbuf == NULL, ("bpf_buffer_alloc: bd_fbuf != NULL")); 102 KASSERT(d->bd_sbuf == NULL, ("bpf_buffer_alloc: bd_sbuf != NULL")); 103 KASSERT(d->bd_hbuf == NULL, ("bpf_buffer_alloc: bd_hbuf != NULL")); 104 105 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); 106 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); 107 d->bd_hbuf = NULL; 108 d->bd_slen = 0; 109 d->bd_hlen = 0; 110} 111 112/* 113 * Simple data copy to the current kernel buffer. 114 */ 115void 116bpf_buffer_append_bytes(struct bpf_d *d, caddr_t buf, u_int offset, 117 void *src, u_int len) 118{ 119 u_char *src_bytes; 120 121 src_bytes = (u_char *)src; 122 bcopy(src_bytes, buf + offset, len); 123} 124 125/* 126 * Scatter-gather data copy from an mbuf chain to the current kernel buffer. 127 */ 128void 129bpf_buffer_append_mbuf(struct bpf_d *d, caddr_t buf, u_int offset, void *src, 130 u_int len) 131{ 132 const struct mbuf *m; 133 u_char *dst; 134 u_int count; 135 136 m = (struct mbuf *)src; 137 dst = (u_char *)buf + offset; 138 while (len > 0) { 139 if (m == NULL) 140 panic("bpf_mcopy"); 141 count = min(m->m_len, len); 142 bcopy(mtod(m, void *), dst, count); 143 m = m->m_next; 144 dst += count; 145 len -= count; 146 } 147} 148 149/* 150 * Free BPF kernel buffers on device close. 151 */ 152void 153bpf_buffer_free(struct bpf_d *d) 154{ 155 156 if (d->bd_sbuf != NULL) 157 free(d->bd_sbuf, M_BPF); 158 if (d->bd_hbuf != NULL) 159 free(d->bd_hbuf, M_BPF); 160 if (d->bd_fbuf != NULL) 161 free(d->bd_fbuf, M_BPF); 162 163#ifdef INVARIANTS 164 d->bd_sbuf = d->bd_hbuf = d->bd_fbuf = (caddr_t)~0; 165#endif 166} 167 168/* 169 * This is a historical initialization that occurs when the BPF descriptor is 170 * first opened. It does not imply selection of a buffer mode, so we don't 171 * allocate buffers here. 172 */ 173void 174bpf_buffer_init(struct bpf_d *d) 175{ 176 177 d->bd_bufsize = bpf_bufsize; 178} 179 180/* 181 * Allocate or resize buffers. 182 */ 183int 184bpf_buffer_ioctl_sblen(struct bpf_d *d, u_int *i) 185{ 186 u_int size; 187 188 BPFD_LOCK(d); 189 if (d->bd_bif != NULL) { 190 BPFD_UNLOCK(d); 191 return (EINVAL); 192 } 193 size = *i; 194 if (size > bpf_maxbufsize) 195 *i = size = bpf_maxbufsize; 196 else if (size < BPF_MINBUFSIZE) 197 *i = size = BPF_MINBUFSIZE; 198 d->bd_bufsize = size; 199 BPFD_UNLOCK(d); 200 return (0); 201} 202 203/* 204 * Copy buffer storage to user space in read(). 205 */ 206int 207bpf_buffer_uiomove(struct bpf_d *d, caddr_t buf, u_int len, struct uio *uio) 208{ 209 210 return (uiomove(buf, len, uio)); 211} 212