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/malloc.h>
73 #include <sys/mbuf.h>
74 #include <sys/socket.h>
75 #include <sys/uio.h>
76 #include <sys/kernel.h>
77 #include <sys/sysctl.h>
78
79 #include <net/if.h>
80 #include <net/bpf.h>
81 #include <net/bpf_buffer.h>
82 #include <net/bpfdesc.h>
83
84 /*
85 * Implement historical kernel memory buffering model for BPF: two malloc(9)
86 * kernel buffers are hung off of the descriptor. The size is fixed prior to
87 * attaching to an ifnet, ad cannot be changed after that. read(2) simply
88 * copies the data to user space using uiomove(9).
89 */
90
91 static int bpf_bufsize = 4096;
92 SYSCTL_INT(_net_bpf, OID_AUTO, bufsize, CTLFLAG_RW,
93 &bpf_bufsize, 0, "Default capture buffer size in bytes");
94 static int bpf_maxbufsize = BPF_MAXBUFSIZE;
95 SYSCTL_INT(_net_bpf, OID_AUTO, maxbufsize, CTLFLAG_RW,
96 &bpf_maxbufsize, 0, "Maximum capture buffer in bytes");
97
98 /*
99 * Simple data copy to the current kernel buffer.
100 */
101 void
102 bpf_buffer_append_bytes(struct bpf_d *d, caddr_t buf, u_int offset,
103 void *src, u_int len)
104 {
105 u_char *src_bytes;
106
107 src_bytes = (u_char *)src;
108 bcopy(src_bytes, buf + offset, len);
109 }
110
111 /*
112 * Scatter-gather data copy from an mbuf chain to the current kernel buffer.
113 */
114 void
115 bpf_buffer_append_mbuf(struct bpf_d *d, caddr_t buf, u_int offset, void *src,
116 u_int len)
117 {
118 const struct mbuf *m;
119 u_char *dst;
120 u_int count;
121
122 m = (struct mbuf *)src;
123 dst = (u_char *)buf + offset;
124 while (len > 0) {
125 if (m == NULL)
126 panic("bpf_mcopy");
127 count = min(m->m_len, len);
128 bcopy(mtod(m, void *), dst, count);
129 m = m->m_next;
130 dst += count;
131 len -= count;
132 }
133 }
134
135 /*
136 * Free BPF kernel buffers on device close.
137 */
138 void
139 bpf_buffer_free(struct bpf_d *d)
140 {
141
142 if (d->bd_sbuf != NULL)
143 free(d->bd_sbuf, M_BPF);
144 if (d->bd_hbuf != NULL)
145 free(d->bd_hbuf, M_BPF);
146 if (d->bd_fbuf != NULL)
147 free(d->bd_fbuf, M_BPF);
148
149 #ifdef INVARIANTS
150 d->bd_sbuf = d->bd_hbuf = d->bd_fbuf = (caddr_t)~0;
151 #endif
152 }
153
154 /*
155 * This is a historical initialization that occurs when the BPF descriptor is
156 * first opened. It does not imply selection of a buffer mode, so we don't
157 * allocate buffers here.
158 */
159 void
160 bpf_buffer_init(struct bpf_d *d)
161 {
162
163 d->bd_bufsize = bpf_bufsize;
164 }
165
166 /*
167 * Allocate or resize buffers.
168 */
169 int
170 bpf_buffer_ioctl_sblen(struct bpf_d *d, u_int *i)
171 {
172 u_int size;
173 caddr_t fbuf, sbuf;
174
175 size = *i;
176 if (size > bpf_maxbufsize)
177 *i = size = bpf_maxbufsize;
178 else if (size < BPF_MINBUFSIZE)
179 *i = size = BPF_MINBUFSIZE;
180
181 /* Allocate buffers immediately */
182 fbuf = (caddr_t)malloc(size, M_BPF, M_WAITOK);
183 sbuf = (caddr_t)malloc(size, M_BPF, M_WAITOK);
184
185 BPFD_LOCK(d);
186 if (d->bd_bif != NULL) {
187 /* Interface already attached, unable to change buffers */
188 BPFD_UNLOCK(d);
189 free(fbuf, M_BPF);
190 free(sbuf, M_BPF);
191 return (EINVAL);
192 }
193
194 /* Free old buffers if set */
195 if (d->bd_fbuf != NULL)
196 free(d->bd_fbuf, M_BPF);
197 if (d->bd_sbuf != NULL)
198 free(d->bd_sbuf, M_BPF);
199
200 /* Fill in new data */
201 d->bd_bufsize = size;
202 d->bd_fbuf = fbuf;
203 d->bd_sbuf = sbuf;
204
205 d->bd_hbuf = NULL;
206 d->bd_slen = 0;
207 d->bd_hlen = 0;
208
209 BPFD_UNLOCK(d);
210 return (0);
211 }
212
213 /*
214 * Copy buffer storage to user space in read().
215 */
216 int
217 bpf_buffer_uiomove(struct bpf_d *d, caddr_t buf, u_int len, struct uio *uio)
218 {
219
220 return (uiomove(buf, len, uio));
221 }
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