FreeBSD/Linux Kernel Cross Reference
sys/net/bpf_buffer.c
1 /*-
2 * Copyright (c) 2007 Seccuris Inc.
3 * All rights reserved.
4 *
5 * This sofware 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/9.0/sys/net/bpf_buffer.c 215792 2010-11-24 05:50:19Z maxim $");
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, "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 void
97 bpf_buffer_alloc(struct bpf_d *d)
98 {
99
100 KASSERT(d->bd_fbuf == NULL, ("bpf_buffer_alloc: bd_fbuf != NULL"));
101 KASSERT(d->bd_sbuf == NULL, ("bpf_buffer_alloc: bd_sbuf != NULL"));
102 KASSERT(d->bd_hbuf == NULL, ("bpf_buffer_alloc: bd_hbuf != NULL"));
103
104 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK);
105 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK);
106 d->bd_hbuf = NULL;
107 d->bd_slen = 0;
108 d->bd_hlen = 0;
109 }
110
111 /*
112 * Simple data copy to the current kernel buffer.
113 */
114 void
115 bpf_buffer_append_bytes(struct bpf_d *d, caddr_t buf, u_int offset,
116 void *src, u_int len)
117 {
118 u_char *src_bytes;
119
120 src_bytes = (u_char *)src;
121 bcopy(src_bytes, buf + offset, len);
122 }
123
124 /*
125 * Scatter-gather data copy from an mbuf chain to the current kernel buffer.
126 */
127 void
128 bpf_buffer_append_mbuf(struct bpf_d *d, caddr_t buf, u_int offset, void *src,
129 u_int len)
130 {
131 const struct mbuf *m;
132 u_char *dst;
133 u_int count;
134
135 m = (struct mbuf *)src;
136 dst = (u_char *)buf + offset;
137 while (len > 0) {
138 if (m == NULL)
139 panic("bpf_mcopy");
140 count = min(m->m_len, len);
141 bcopy(mtod(m, void *), dst, count);
142 m = m->m_next;
143 dst += count;
144 len -= count;
145 }
146 }
147
148 /*
149 * Free BPF kernel buffers on device close.
150 */
151 void
152 bpf_buffer_free(struct bpf_d *d)
153 {
154
155 if (d->bd_sbuf != NULL)
156 free(d->bd_sbuf, M_BPF);
157 if (d->bd_hbuf != NULL)
158 free(d->bd_hbuf, M_BPF);
159 if (d->bd_fbuf != NULL)
160 free(d->bd_fbuf, M_BPF);
161
162 #ifdef INVARIANTS
163 d->bd_sbuf = d->bd_hbuf = d->bd_fbuf = (caddr_t)~0;
164 #endif
165 }
166
167 /*
168 * This is a historical initialization that occurs when the BPF descriptor is
169 * first opened. It does not imply selection of a buffer mode, so we don't
170 * allocate buffers here.
171 */
172 void
173 bpf_buffer_init(struct bpf_d *d)
174 {
175
176 d->bd_bufsize = bpf_bufsize;
177 }
178
179 /*
180 * Allocate or resize buffers.
181 */
182 int
183 bpf_buffer_ioctl_sblen(struct bpf_d *d, u_int *i)
184 {
185 u_int size;
186
187 BPFD_LOCK(d);
188 if (d->bd_bif != NULL) {
189 BPFD_UNLOCK(d);
190 return (EINVAL);
191 }
192 size = *i;
193 if (size > bpf_maxbufsize)
194 *i = size = bpf_maxbufsize;
195 else if (size < BPF_MINBUFSIZE)
196 *i = size = BPF_MINBUFSIZE;
197 d->bd_bufsize = size;
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 }
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