FreeBSD/Linux Kernel Cross Reference
sys/net/bpf_buffer.c
1 /*-
2 * Copyright (c) 2007 Seccuris Inc.
3 * All rights reserved.
4 *
5 * This software 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: releng/8.4/sys/net/bpf_buffer.c 247732 2013-03-03 21:48:40Z melifaro $");
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
89 static int bpf_bufsize = 4096;
90 SYSCTL_INT(_net_bpf, OID_AUTO, bufsize, CTLFLAG_RW,
91 &bpf_bufsize, 0, "Maximum 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, "Default 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 u_int count;
119
120 m = (struct mbuf *)src;
121 dst = (u_char *)buf + offset;
122 while (len > 0) {
123 if (m == NULL)
124 panic("bpf_mcopy");
125 count = min(m->m_len, len);
126 bcopy(mtod(m, void *), dst, count);
127 m = m->m_next;
128 dst += count;
129 len -= count;
130 }
131 }
132
133 /*
134 * Free BPF kernel buffers on device close.
135 */
136 void
137 bpf_buffer_free(struct bpf_d *d)
138 {
139
140 if (d->bd_sbuf != NULL)
141 free(d->bd_sbuf, M_BPF);
142 if (d->bd_hbuf != NULL)
143 free(d->bd_hbuf, M_BPF);
144 if (d->bd_fbuf != NULL)
145 free(d->bd_fbuf, M_BPF);
146
147 #ifdef INVARIANTS
148 d->bd_sbuf = d->bd_hbuf = d->bd_fbuf = (caddr_t)~0;
149 #endif
150 }
151
152 /*
153 * This is a historical initialization that occurs when the BPF descriptor is
154 * first opened. It does not imply selection of a buffer mode, so we don't
155 * allocate buffers here.
156 */
157 void
158 bpf_buffer_init(struct bpf_d *d)
159 {
160
161 d->bd_bufsize = bpf_bufsize;
162 }
163
164 /*
165 * Allocate or resize buffers.
166 */
167 int
168 bpf_buffer_ioctl_sblen(struct bpf_d *d, u_int *i)
169 {
170 u_int size;
171 caddr_t fbuf, sbuf;
172
173 size = *i;
174 if (size > bpf_maxbufsize)
175 *i = size = bpf_maxbufsize;
176 else if (size < BPF_MINBUFSIZE)
177 *i = size = BPF_MINBUFSIZE;
178
179 /* Allocate buffers immediately */
180 fbuf = (caddr_t)malloc(size, M_BPF, M_WAITOK);
181 sbuf = (caddr_t)malloc(size, M_BPF, M_WAITOK);
182
183 BPFD_LOCK(d);
184 if (d->bd_bif != NULL) {
185 /* Interface already attached, unable to change buffers */
186 BPFD_UNLOCK(d);
187 free(fbuf, M_BPF);
188 free(sbuf, M_BPF);
189 return (EINVAL);
190 }
191
192 /* Free old buffers if set */
193 if (d->bd_fbuf != NULL)
194 free(d->bd_fbuf, M_BPF);
195 if (d->bd_sbuf != NULL)
196 free(d->bd_sbuf, M_BPF);
197
198 /* Fill in new data */
199 d->bd_bufsize = size;
200 d->bd_fbuf = fbuf;
201 d->bd_sbuf = sbuf;
202
203 d->bd_hbuf = NULL;
204 d->bd_slen = 0;
205 d->bd_hlen = 0;
206
207 BPFD_UNLOCK(d);
208 return (0);
209 }
210
211 /*
212 * Copy buffer storage to user space in read().
213 */
214 int
215 bpf_buffer_uiomove(struct bpf_d *d, caddr_t buf, u_int len, struct uio *uio)
216 {
217
218 return (uiomove(buf, len, uio));
219 }
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