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
bpf_buffer_append_bytes(struct bpf_d * d,caddr_t buf,u_int offset,void * src,u_int len)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
bpf_buffer_append_mbuf(struct bpf_d * d,caddr_t buf,u_int offset,void * src,u_int len)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
bpf_buffer_free(struct bpf_d * d)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
bpf_buffer_init(struct bpf_d * d)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
bpf_buffer_ioctl_sblen(struct bpf_d * d,u_int * i)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
bpf_buffer_uiomove(struct bpf_d * d,caddr_t buf,u_int len,struct uio * uio)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