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 } 211