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 * @(#)bpf.c 8.4 (Berkeley) 1/9/95 64 */ 65 66 #include <sys/cdefs.h> 67 __FBSDID("$FreeBSD$"); 68 69 #include "opt_bpf.h" 70 71 #include <sys/param.h> 72 #include <sys/lock.h> 73 #include <sys/malloc.h> 74 #include <sys/mbuf.h> 75 #include <sys/mutex.h> 76 #include <sys/socket.h> 77 #include <sys/uio.h> 78 #include <sys/kernel.h> 79 #include <sys/sysctl.h> 80 81 #include <net/if.h> 82 #include <net/bpf.h> 83 #include <net/bpf_buffer.h> 84 #include <net/bpfdesc.h> 85 86 /* 87 * Implement historical kernel memory buffering model for BPF: two malloc(9) 88 * kernel buffers are hung off of the descriptor. The size is fixed prior to 89 * attaching to an ifnet, ad cannot be changed after that. read(2) simply 90 * copies the data to user space using uiomove(9). 91 */ 92 93 static int bpf_bufsize = 4096; 94 SYSCTL_INT(_net_bpf, OID_AUTO, bufsize, CTLFLAG_RW, 95 &bpf_bufsize, 0, "Default capture buffer size in bytes"); 96 static int bpf_maxbufsize = BPF_MAXBUFSIZE; 97 SYSCTL_INT(_net_bpf, OID_AUTO, maxbufsize, CTLFLAG_RW, 98 &bpf_maxbufsize, 0, "Maximum capture buffer in bytes"); 99 100 /* 101 * Simple data copy to the current kernel buffer. 102 */ 103 void 104 bpf_buffer_append_bytes(struct bpf_d *d, caddr_t buf, u_int offset, 105 void *src, u_int len) 106 { 107 u_char *src_bytes; 108 109 src_bytes = (u_char *)src; 110 bcopy(src_bytes, buf + offset, len); 111 } 112 113 /* 114 * Scatter-gather data copy from an mbuf chain to the current kernel buffer. 115 */ 116 void 117 bpf_buffer_append_mbuf(struct bpf_d *d, caddr_t buf, u_int offset, void *src, 118 u_int len) 119 { 120 const struct mbuf *m; 121 u_char *dst; 122 123 m = (struct mbuf *)src; 124 dst = (u_char *)buf + offset; 125 m_copydata(m, 0, len, dst); 126 } 127 128 /* 129 * Free BPF kernel buffers on device close. 130 */ 131 void 132 bpf_buffer_free(struct bpf_d *d) 133 { 134 135 if (d->bd_sbuf != NULL) 136 free(d->bd_sbuf, M_BPF); 137 if (d->bd_hbuf != NULL) 138 free(d->bd_hbuf, M_BPF); 139 if (d->bd_fbuf != NULL) 140 free(d->bd_fbuf, M_BPF); 141 142 #ifdef INVARIANTS 143 d->bd_sbuf = d->bd_hbuf = d->bd_fbuf = (caddr_t)~0; 144 #endif 145 } 146 147 /* 148 * This is a historical initialization that occurs when the BPF descriptor is 149 * first opened. It does not imply selection of a buffer mode, so we don't 150 * allocate buffers here. 151 */ 152 void 153 bpf_buffer_init(struct bpf_d *d) 154 { 155 156 d->bd_bufsize = bpf_bufsize; 157 } 158 159 /* 160 * Allocate or resize buffers. 161 */ 162 int 163 bpf_buffer_ioctl_sblen(struct bpf_d *d, u_int *i) 164 { 165 u_int size; 166 caddr_t fbuf, sbuf; 167 168 size = *i; 169 if (size > bpf_maxbufsize) 170 *i = size = bpf_maxbufsize; 171 else if (size < BPF_MINBUFSIZE) 172 *i = size = BPF_MINBUFSIZE; 173 174 /* Allocate buffers immediately */ 175 fbuf = (caddr_t)malloc(size, M_BPF, M_WAITOK); 176 sbuf = (caddr_t)malloc(size, M_BPF, M_WAITOK); 177 178 BPFD_LOCK(d); 179 if (d->bd_bif != NULL) { 180 /* Interface already attached, unable to change buffers */ 181 BPFD_UNLOCK(d); 182 free(fbuf, M_BPF); 183 free(sbuf, M_BPF); 184 return (EINVAL); 185 } 186 187 /* Free old buffers if set */ 188 if (d->bd_fbuf != NULL) 189 free(d->bd_fbuf, M_BPF); 190 if (d->bd_sbuf != NULL) 191 free(d->bd_sbuf, M_BPF); 192 193 /* Fill in new data */ 194 d->bd_bufsize = size; 195 d->bd_fbuf = fbuf; 196 d->bd_sbuf = sbuf; 197 198 d->bd_hbuf = NULL; 199 d->bd_slen = 0; 200 d->bd_hlen = 0; 201 202 BPFD_UNLOCK(d); 203 return (0); 204 } 205 206 /* 207 * Copy buffer storage to user space in read(). 208 */ 209 int 210 bpf_buffer_uiomove(struct bpf_d *d, caddr_t buf, u_int len, struct uio *uio) 211 { 212 213 return (uiomove(buf, len, uio)); 214 } 215