bpf_buffer.c revision 196150
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 196150 2009-08-12 17:28:53Z 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/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, "Maximum capture buffer size in bytes"); 92static int bpf_maxbufsize = BPF_MAXBUFSIZE; 93SYSCTL_INT(_net_bpf, OID_AUTO, maxbufsize, CTLFLAG_RW, 94 &bpf_maxbufsize, 0, "Default capture buffer in bytes"); 95 96void 97bpf_buffer_alloc(struct bpf_d *d) 98{ 99 100 KASSERT(d->bd_fbuf == NULL, ("bpf_buffer_alloc: bd_fbuf != NULL")); 101 KASSERT(d->bd_sbuf == NULL, ("bpf_buffer_alloc: bd_sbuf != NULL")); 102 KASSERT(d->bd_hbuf == NULL, ("bpf_buffer_alloc: bd_hbuf != NULL")); 103 104 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); 105 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); 106 d->bd_hbuf = NULL; 107 d->bd_slen = 0; 108 d->bd_hlen = 0; 109} 110 111/* 112 * Simple data copy to the current kernel buffer. 113 */ 114void 115bpf_buffer_append_bytes(struct bpf_d *d, caddr_t buf, u_int offset, 116 void *src, u_int len) 117{ 118 u_char *src_bytes; 119 120 src_bytes = (u_char *)src; 121 bcopy(src_bytes, buf + offset, len); 122} 123 124/* 125 * Scatter-gather data copy from an mbuf chain to the current kernel buffer. 126 */ 127void 128bpf_buffer_append_mbuf(struct bpf_d *d, caddr_t buf, u_int offset, void *src, 129 u_int len) 130{ 131 const struct mbuf *m; 132 u_char *dst; 133 u_int count; 134 135 m = (struct mbuf *)src; 136 dst = (u_char *)buf + offset; 137 while (len > 0) { 138 if (m == NULL) 139 panic("bpf_mcopy"); 140 count = min(m->m_len, len); 141 bcopy(mtod(m, void *), dst, count); 142 m = m->m_next; 143 dst += count; 144 len -= count; 145 } 146} 147 148/* 149 * Free BPF kernel buffers on device close. 150 */ 151void 152bpf_buffer_free(struct bpf_d *d) 153{ 154 155 if (d->bd_sbuf != NULL) 156 free(d->bd_sbuf, M_BPF); 157 if (d->bd_hbuf != NULL) 158 free(d->bd_hbuf, M_BPF); 159 if (d->bd_fbuf != NULL) 160 free(d->bd_fbuf, M_BPF); 161 162#ifdef INVARIANTS 163 d->bd_sbuf = d->bd_hbuf = d->bd_fbuf = (caddr_t)~0; 164#endif 165} 166 167/* 168 * This is a historical initialization that occurs when the BPF descriptor is 169 * first opened. It does not imply selection of a buffer mode, so we don't 170 * allocate buffers here. 171 */ 172void 173bpf_buffer_init(struct bpf_d *d) 174{ 175 176 d->bd_bufsize = bpf_bufsize; 177} 178 179/* 180 * Allocate or resize buffers. 181 */ 182int 183bpf_buffer_ioctl_sblen(struct bpf_d *d, u_int *i) 184{ 185 u_int size; 186 187 BPFD_LOCK(d); 188 if (d->bd_bif != NULL) { 189 BPFD_UNLOCK(d); 190 return (EINVAL); 191 } 192 size = *i; 193 if (size > bpf_maxbufsize) 194 *i = size = bpf_maxbufsize; 195 else if (size < BPF_MINBUFSIZE) 196 *i = size = BPF_MINBUFSIZE; 197 d->bd_bufsize = size; 198 BPFD_UNLOCK(d); 199 return (0); 200} 201 202/* 203 * Copy buffer storage to user space in read(). 204 */ 205int 206bpf_buffer_uiomove(struct bpf_d *d, caddr_t buf, u_int len, struct uio *uio) 207{ 208 209 return (uiomove(buf, len, uio)); 210} 211