FreeBSD/Linux Kernel Cross Reference
sys/net/bpf_buffer.c
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 }
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