1 /* $OpenBSD: pf.c,v 1.19 2023/03/08 04:43:13 guenther Exp $ */
2
3 /*
4 * Copyright (c) 1993-95 Mats O Jansson. All rights reserved.
5 * Copyright (c) 1990 The Regents of the University of California.
6 * All rights reserved.
7 *
8 * This code is partly derived from rarpd.
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 ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #include <sys/types.h>
32 #include <sys/time.h>
33 #include <sys/ioctl.h>
34 #include <sys/socket.h>
35 #include <sys/uio.h>
36 #include <net/if.h>
37
38 #include <net/bpf.h>
39
40 #include <netinet/in.h>
41 #include <netinet/if_ether.h>
42
43 #include <netdb.h>
44 #include <ctype.h>
45 #include <string.h>
46 #include <err.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <stdio.h>
50 #include <syslog.h>
51 #include <unistd.h>
52
53 #include "common/mopdef.h"
54
55 /*
56 * Variables
57 */
58
59 extern int promisc;
60
61 /*
62 * Return information to device.c how to open device.
63 * In this case the driver can handle both Ethernet type II and
64 * IEEE 802.3 frames (SNAP) in a single pfOpen.
65 */
66 int
pfTrans(char * interface)67 pfTrans(char *interface)
68 {
69 return (TRANS_ETHER + TRANS_8023 + TRANS_AND);
70 }
71
72 /*
73 * Open and initialize packet filter.
74 */
75 int
pfInit(char * interface,int mode,u_short protocol,int typ)76 pfInit(char *interface, int mode, u_short protocol, int typ)
77 {
78 int fd;
79 struct ifreq ifr;
80 u_int dlt;
81 int immediate;
82
83 static struct bpf_insn insns[] = {
84 BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 12),
85 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 4, 0),
86 BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 20),
87 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 0, 3),
88 BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 14),
89 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0xaaaa, 0, 1),
90 BPF_STMT(BPF_RET | BPF_K, 1520),
91 BPF_STMT(BPF_RET | BPF_K, 0),
92 };
93 static struct bpf_program filter = {
94 sizeof insns / sizeof(insns[0]),
95 insns
96 };
97
98 if ((fd = open("/dev/bpf", mode)) == -1) {
99 syslog(LOG_ERR,"pfInit: open bpf %m");
100 return (-1);
101 }
102
103 /* Set immediate mode so packets are processed as they arrive. */
104 immediate = 1;
105 if (ioctl(fd, BIOCIMMEDIATE, &immediate) < 0) {
106 syslog(LOG_ERR,"pfInit: BIOCIMMEDIATE: %m");
107 return (-1);
108 }
109 strncpy(ifr.ifr_name, interface, sizeof ifr.ifr_name);
110 if (ioctl(fd, BIOCSETIF, &ifr) < 0) {
111 syslog(LOG_ERR,"pfInit: BIOCSETIF: %m");
112 return (-1);
113 }
114 /* Check that the data link layer is an Ethernet; this code won't work
115 * with anything else. */
116 if (ioctl(fd, BIOCGDLT, &dlt) < 0) {
117 syslog(LOG_ERR,"pfInit: BIOCGDLT: %m");
118 return (-1);
119 }
120 if (dlt != DLT_EN10MB) {
121 syslog(LOG_ERR,"pfInit: %s is not ethernet", interface);
122 return (-1);
123 }
124 if (promisc)
125 /* Set promiscuous mode. */
126 if (ioctl(fd, BIOCPROMISC, 0) < 0) {
127 syslog(LOG_ERR,"pfInit: BIOCPROMISC: %m");
128 return (-1);
129 }
130
131 /* Set filter program. */
132 insns[1].k = protocol;
133 insns[3].k = protocol;
134
135 if (ioctl(fd, BIOCSETF, &filter) < 0) {
136 syslog(LOG_ERR,"pfInit: BIOCSETF: %m");
137 return (-1);
138 }
139
140 /* XXX set the same write filter (for protocol only) */
141 if (ioctl(fd, BIOCSETWF, &filter) < 0) {
142 syslog(LOG_ERR,"pfInit: BIOCSETWF: %m");
143 return (-1);
144 }
145
146 /* Lock the interface to prevent further changes */
147 if (ioctl(fd, BIOCLOCK) < 0) {
148 syslog(LOG_ERR,"pfInit: BIOCLOCK: %m");
149 return (-1);
150 }
151
152 return (fd);
153 }
154
155 /*
156 * Add a Multicast address to the interface
157 */
158 int
pfAddMulti(int s,char * interface,char * addr)159 pfAddMulti(int s, char *interface, char *addr)
160 {
161 struct ifreq ifr;
162 int fd;
163
164 strncpy(ifr.ifr_name, interface, sizeof(ifr.ifr_name) - 1);
165 ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = 0;
166
167 ifr.ifr_addr.sa_family = AF_UNSPEC;
168 bcopy(addr, ifr.ifr_addr.sa_data, 6);
169
170 /*
171 * open a socket, temporarily, to use for SIOC* ioctls
172 */
173 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
174 syslog(LOG_ERR, "pfAddMulti: socket: %m");
175 return (-1);
176 }
177 if (ioctl(fd, SIOCADDMULTI, &ifr) < 0) {
178 syslog(LOG_ERR, "pfAddMulti: SIOCADDMULTI: %m");
179 close(fd);
180 return (-1);
181 }
182 close(fd);
183
184 return (0);
185 }
186
187 /*
188 * Delete a Multicast address from the interface
189 */
190 int
pfDelMulti(int s,char * interface,char * addr)191 pfDelMulti(int s, char *interface, char *addr)
192 {
193 struct ifreq ifr;
194 int fd;
195
196 strncpy(ifr.ifr_name, interface, sizeof (ifr.ifr_name) - 1);
197 ifr.ifr_name[sizeof(ifr.ifr_name)-1] = 0;
198
199 ifr.ifr_addr.sa_family = AF_UNSPEC;
200 bcopy(addr, ifr.ifr_addr.sa_data, 6);
201
202 /*
203 * open a socket, temporarily, to use for SIOC* ioctls
204 *
205 */
206 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
207 syslog(LOG_ERR, "pfDelMulti: socket: %m");
208 return (-1);
209 }
210 if (ioctl(fd, SIOCDELMULTI, &ifr) < 0) {
211 syslog(LOG_ERR, "pfAddMulti: SIOCDELMULTI: %m");
212 close(fd);
213 return (-1);
214 }
215 close(fd);
216
217 return (0);
218 }
219
220 /*
221 * read a packet
222 */
223 int
pfRead(int fd,u_char * buf,int len)224 pfRead(int fd, u_char *buf, int len)
225 {
226 return (read(fd, buf, len));
227 }
228
229 /*
230 * write a packet
231 */
232 int
pfWrite(int fd,u_char * buf,int len,int trans)233 pfWrite(int fd, u_char *buf, int len, int trans)
234 {
235 struct iovec iov[2];
236
237 /* XXX */
238 switch (trans) {
239 case TRANS_8023:
240 iov[0].iov_base = buf;
241 iov[0].iov_len = 22;
242 iov[1].iov_base = buf + 22;
243 iov[1].iov_len = len - 22;
244 break;
245 default:
246 iov[0].iov_base = buf;
247 iov[0].iov_len = 14;
248 iov[1].iov_base = buf + 14;
249 iov[1].iov_len = len - 14;
250 break;
251 }
252
253 if (writev(fd, iov, 2) == len)
254 return (len);
255
256 return (-1);
257 }
258
259