ndbootd-bpf.c revision 1.3 1 1.3 fredette /* $NetBSD: ndbootd-bpf.c,v 1.3 2001/05/23 02:59:36 fredette Exp $ */
2 1.2 fredette
3 1.1 fredette /* ndbootd-bpf.c - the Sun Network Disk (nd) daemon BPF component: */
4 1.1 fredette
5 1.1 fredette /*
6 1.1 fredette * Copyright (c) 2001 Matthew Fredette. All rights reserved.
7 1.1 fredette *
8 1.1 fredette * Redistribution and use in source and binary forms, with or without
9 1.1 fredette * modification, are permitted provided that the following conditions
10 1.1 fredette * are met:
11 1.1 fredette * 1. Redistributions of source code must retain the above copyright
12 1.1 fredette * notice, this list of conditions and the following disclaimer.
13 1.1 fredette * 2. Redistributions in binary form must reproduce the above copyright
14 1.1 fredette * notice, this list of conditions and the following disclaimer in the
15 1.1 fredette * documentation and/or other materials provided with the distribution.
16 1.1 fredette * 3. All advertising materials mentioning features or use of this software
17 1.1 fredette * must display the following acknowledgement:
18 1.1 fredette * This product includes software developed by Matthew Fredette.
19 1.1 fredette * 4. The name of Matthew Fredette may not be used to endorse or promote
20 1.1 fredette * products derived from this software without specific prior written
21 1.1 fredette * permission.
22 1.1 fredette *
23 1.1 fredette * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
24 1.1 fredette * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
25 1.1 fredette * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
26 1.1 fredette */
27 1.1 fredette
28 1.3 fredette /* <<Header: /data/home/fredette/project/THE-WEIGHT-CVS/ndbootd/config/ndbootd-bpf.c,v 1.4 2001/05/23 02:35:49 fredette Exp >> */
29 1.1 fredette
30 1.1 fredette /*
31 1.1 fredette * <<Log: ndbootd-bpf.c,v >>
32 1.3 fredette * Revision 1.4 2001/05/23 02:35:49 fredette
33 1.3 fredette * Changed many debugging printfs to compile quietly on the
34 1.3 fredette * alpha. Patch from Andrew Brown <atatat (at) atatdot.net>.
35 1.3 fredette *
36 1.1 fredette * Revision 1.3 2001/05/22 13:13:24 fredette
37 1.1 fredette * Ran indent(1) with NetBSD's KNF-approximating profile.
38 1.1 fredette *
39 1.1 fredette * Revision 1.2 2001/05/09 20:50:46 fredette
40 1.1 fredette * Removed an unnecessary comment.
41 1.1 fredette *
42 1.1 fredette * Revision 1.1 2001/01/29 15:12:13 fredette
43 1.1 fredette * Added.
44 1.1 fredette *
45 1.1 fredette */
46 1.1 fredette
47 1.3 fredette static const char _ndbootd_bpf_c_rcsid[] = "<<Id: ndbootd-bpf.c,v 1.4 2001/05/23 02:35:49 fredette Exp >>";
48 1.1 fredette
49 1.1 fredette /* includes: */
50 1.1 fredette #include <net/bpf.h>
51 1.1 fredette
52 1.1 fredette /* structures: */
53 1.1 fredette struct _ndbootd_interface_bpf {
54 1.1 fredette
55 1.1 fredette /* the size of the packet buffer for the interface: */
56 1.1 fredette size_t _ndbootd_interface_bpf_buffer_size;
57 1.1 fredette
58 1.1 fredette /* the packet buffer for the interface: */
59 1.1 fredette char *_ndbootd_interface_bpf_buffer;
60 1.1 fredette
61 1.1 fredette /* the next offset within the packet buffer, and the end of the data
62 1.1 fredette * in the packet buffer: */
63 1.1 fredette size_t _ndbootd_interface_bpf_buffer_offset;
64 1.1 fredette size_t _ndbootd_interface_bpf_buffer_end;
65 1.1 fredette };
66 1.1 fredette
67 1.1 fredette /* the BPF program to capture ND packets: */
68 1.1 fredette static struct bpf_insn ndboot_bpf_filter[] = {
69 1.1 fredette
70 1.1 fredette /* drop this packet if its ethertype isn't ETHERTYPE_IP: */
71 1.1 fredette BPF_STMT(BPF_LD + BPF_H + BPF_ABS, NDBOOTD_OFFSETOF(struct ether_header, ether_type)),
72 1.1 fredette BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 9),
73 1.1 fredette
74 1.1 fredette /* drop this packet if its IP protocol isn't IPPROTO_ND: */
75 1.1 fredette BPF_STMT(BPF_LD + BPF_B + BPF_ABS, sizeof(struct ether_header) + NDBOOTD_OFFSETOF(struct ip, ip_p)),
76 1.1 fredette BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_ND, 0, 7),
77 1.1 fredette
78 1.1 fredette /* drop this packet if it's a fragment: */
79 1.1 fredette BPF_STMT(BPF_LD + BPF_H + BPF_ABS, sizeof(struct ether_header) + NDBOOTD_OFFSETOF(struct ip, ip_off)),
80 1.1 fredette BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x3fff, 5, 0),
81 1.1 fredette
82 1.1 fredette /* drop this packet if it is carrying data (we only want requests,
83 1.1 fredette * which have no data): */
84 1.1 fredette BPF_STMT(BPF_LD + BPF_H + BPF_ABS, sizeof(struct ether_header) + NDBOOTD_OFFSETOF(struct ip, ip_len)),
85 1.1 fredette BPF_STMT(BPF_LDX + BPF_B + BPF_MSH, sizeof(struct ether_header)),
86 1.1 fredette BPF_STMT(BPF_ALU + BPF_SUB + BPF_X, 0),
87 1.1 fredette BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, sizeof(struct ndboot_packet), 0, 1),
88 1.1 fredette
89 1.1 fredette /* accept this packet: */
90 1.1 fredette BPF_STMT(BPF_RET + BPF_K, (u_int) -1),
91 1.1 fredette
92 1.1 fredette /* drop this packet: */
93 1.1 fredette BPF_STMT(BPF_RET + BPF_K, 0),
94 1.1 fredette };
95 1.1 fredette
96 1.1 fredette /* this opens a raw socket using BPF. */
97 1.1 fredette int
98 1.1 fredette ndbootd_raw_open(struct ndbootd_interface * interface)
99 1.1 fredette {
100 1.1 fredette int network_fd;
101 1.1 fredette #define DEV_BPF_FORMAT "/dev/bpf%d"
102 1.1 fredette char dev_bpf_filename[sizeof(DEV_BPF_FORMAT) + (sizeof(int) * 3) + 1];
103 1.1 fredette int minor;
104 1.1 fredette int saved_errno;
105 1.1 fredette u_int bpf_opt;
106 1.1 fredette struct bpf_version version;
107 1.1 fredette u_int packet_buffer_size;
108 1.1 fredette struct bpf_program program;
109 1.1 fredette struct _ndbootd_interface_bpf *interface_bpf;
110 1.1 fredette
111 1.1 fredette /* loop trying to open a /dev/bpf device: */
112 1.1 fredette for (minor = 0;; minor++) {
113 1.1 fredette
114 1.1 fredette /* form the name of the next device to try, then try opening
115 1.1 fredette * it. if we succeed, we're done: */
116 1.1 fredette sprintf(dev_bpf_filename, DEV_BPF_FORMAT, minor);
117 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: trying %s", dev_bpf_filename));
118 1.1 fredette if ((network_fd = open(dev_bpf_filename, O_RDWR)) >= 0) {
119 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: opened %s", dev_bpf_filename));
120 1.1 fredette break;
121 1.1 fredette }
122 1.1 fredette /* we failed to open this device. if this device was simply
123 1.1 fredette * busy, loop: */
124 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: failed to open %s: %s", dev_bpf_filename, strerror(errno)));
125 1.1 fredette if (errno == EBUSY) {
126 1.1 fredette continue;
127 1.1 fredette }
128 1.1 fredette /* otherwise, we have failed: */
129 1.1 fredette return (-1);
130 1.1 fredette }
131 1.1 fredette
132 1.1 fredette /* this macro helps in closing the BPF socket on error: */
133 1.1 fredette #define _NDBOOTD_RAW_OPEN_ERROR(x) saved_errno = errno; x; errno = saved_errno
134 1.1 fredette
135 1.1 fredette /* check the BPF version: */
136 1.1 fredette if (ioctl(network_fd, BIOCVERSION, &version) < 0) {
137 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: failed to get the BPF version on %s: %s",
138 1.1 fredette dev_bpf_filename, strerror(errno)));
139 1.1 fredette _NDBOOTD_RAW_OPEN_ERROR(close(network_fd));
140 1.1 fredette return (-1);
141 1.1 fredette }
142 1.1 fredette if (version.bv_major != BPF_MAJOR_VERSION
143 1.1 fredette || version.bv_minor < BPF_MINOR_VERSION) {
144 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: kernel BPF version is %d.%d, my BPF version is %d.%d",
145 1.1 fredette version.bv_major, version.bv_minor,
146 1.1 fredette BPF_MAJOR_VERSION, BPF_MINOR_VERSION));
147 1.1 fredette close(network_fd);
148 1.1 fredette errno = ENXIO;
149 1.1 fredette return (-1);
150 1.1 fredette }
151 1.1 fredette /* put the BPF device into immediate mode: */
152 1.1 fredette bpf_opt = TRUE;
153 1.1 fredette if (ioctl(network_fd, BIOCIMMEDIATE, &bpf_opt) < 0) {
154 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: failed to put %s into immediate mode: %s",
155 1.1 fredette dev_bpf_filename, strerror(errno)));
156 1.1 fredette _NDBOOTD_RAW_OPEN_ERROR(close(network_fd));
157 1.1 fredette return (-1);
158 1.1 fredette }
159 1.1 fredette /* tell the BPF device we're providing complete Ethernet headers: */
160 1.1 fredette bpf_opt = TRUE;
161 1.1 fredette if (ioctl(network_fd, BIOCSHDRCMPLT, &bpf_opt) < 0) {
162 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: failed to put %s into complete-headers mode: %s",
163 1.1 fredette dev_bpf_filename, strerror(errno)));
164 1.1 fredette _NDBOOTD_RAW_OPEN_ERROR(close(network_fd));
165 1.1 fredette return (-1);
166 1.1 fredette }
167 1.1 fredette /* point the BPF device at the interface we're using: */
168 1.1 fredette if (ioctl(network_fd, BIOCSETIF, interface->ndbootd_interface_ifreq) < 0) {
169 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: failed to point BPF socket at %s: %s",
170 1.1 fredette interface->ndbootd_interface_ifreq->ifr_name, strerror(errno)));
171 1.1 fredette saved_errno = errno;
172 1.1 fredette close(network_fd);
173 1.1 fredette errno = saved_errno;
174 1.1 fredette return (-1);
175 1.1 fredette }
176 1.1 fredette /* set the filter on the BPF device: */
177 1.1 fredette program.bf_len = sizeof(ndboot_bpf_filter) / sizeof(ndboot_bpf_filter[0]);
178 1.1 fredette program.bf_insns = ndboot_bpf_filter;
179 1.1 fredette if (ioctl(network_fd, BIOCSETF, &program) < 0) {
180 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: failed to set the filter on %s: %s",
181 1.1 fredette dev_bpf_filename, strerror(errno)));
182 1.1 fredette _NDBOOTD_RAW_OPEN_ERROR(close(network_fd));
183 1.1 fredette return (-1);
184 1.1 fredette }
185 1.1 fredette /* get the BPF read buffer size: */
186 1.1 fredette if (ioctl(network_fd, BIOCGBLEN, &packet_buffer_size) < 0) {
187 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: failed to read the buffer size for %s: %s",
188 1.1 fredette dev_bpf_filename, strerror(errno)));
189 1.1 fredette _NDBOOTD_RAW_OPEN_ERROR(close(network_fd));
190 1.1 fredette return (-1);
191 1.1 fredette }
192 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: buffer size for %s is %u",
193 1.1 fredette dev_bpf_filename, packet_buffer_size));
194 1.1 fredette
195 1.1 fredette /* allocate our private interface information and we're done: */
196 1.1 fredette interface->ndbootd_interface_fd = network_fd;
197 1.1 fredette interface_bpf = ndbootd_new0(struct _ndbootd_interface_bpf, 1);
198 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer_size = packet_buffer_size;
199 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer = ndbootd_new(char, packet_buffer_size);
200 1.1 fredette interface->_ndbootd_interface_raw_private = interface_bpf;
201 1.1 fredette return (0);
202 1.1 fredette #undef _NDBOOTD_RAW_OPEN_ERROR
203 1.1 fredette }
204 1.1 fredette
205 1.1 fredette /* this reads a raw packet: */
206 1.1 fredette int
207 1.1 fredette ndbootd_raw_read(struct ndbootd_interface * interface, void *packet_buffer, size_t packet_buffer_size)
208 1.1 fredette {
209 1.1 fredette struct _ndbootd_interface_bpf *interface_bpf;
210 1.1 fredette ssize_t buffer_end;
211 1.1 fredette struct bpf_hdr the_bpf_header;
212 1.1 fredette fd_set fdset_read;
213 1.1 fredette
214 1.1 fredette /* recover our state: */
215 1.1 fredette interface_bpf = (struct _ndbootd_interface_bpf *) interface->_ndbootd_interface_raw_private;
216 1.1 fredette
217 1.1 fredette /* loop until we have something to return: */
218 1.1 fredette for (;;) {
219 1.1 fredette
220 1.1 fredette /* if the buffer is empty, fill it: */
221 1.1 fredette if (interface_bpf->_ndbootd_interface_bpf_buffer_offset
222 1.1 fredette >= interface_bpf->_ndbootd_interface_bpf_buffer_end) {
223 1.1 fredette
224 1.1 fredette /* select on the BPF socket: */
225 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: calling select"));
226 1.1 fredette FD_ZERO(&fdset_read);
227 1.1 fredette FD_SET(interface->ndbootd_interface_fd, &fdset_read);
228 1.1 fredette switch (select(interface->ndbootd_interface_fd + 1, &fdset_read, NULL, NULL, NULL)) {
229 1.1 fredette case 0:
230 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: select returned zero"));
231 1.1 fredette continue;
232 1.1 fredette case 1:
233 1.1 fredette break;
234 1.1 fredette default:
235 1.1 fredette if (errno == EINTR) {
236 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: select got EINTR"));
237 1.1 fredette continue;
238 1.1 fredette }
239 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: select failed: %s", strerror(errno)));
240 1.1 fredette return (-1);
241 1.1 fredette }
242 1.1 fredette assert(FD_ISSET(interface->ndbootd_interface_fd, &fdset_read));
243 1.1 fredette
244 1.1 fredette /* read the BPF socket: */
245 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: calling read"));
246 1.1 fredette buffer_end = read(interface->ndbootd_interface_fd,
247 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer,
248 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer_size);
249 1.1 fredette if (buffer_end <= 0) {
250 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: failed to read packets: %s", strerror(errno)));
251 1.1 fredette return (-1);
252 1.1 fredette }
253 1.3 fredette _NDBOOTD_DEBUG((fp, "bpf: read %ld bytes of packets", (long) buffer_end));
254 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer_offset = 0;
255 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer_end = buffer_end;
256 1.1 fredette }
257 1.1 fredette /* if there's not enough for a BPF header, flush the buffer: */
258 1.1 fredette if ((interface_bpf->_ndbootd_interface_bpf_buffer_offset
259 1.1 fredette + sizeof(the_bpf_header))
260 1.1 fredette > interface_bpf->_ndbootd_interface_bpf_buffer_end) {
261 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: flushed garbage BPF header bytes"));
262 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer_end = 0;
263 1.1 fredette continue;
264 1.1 fredette }
265 1.1 fredette /* get the BPF header and check it: */
266 1.1 fredette memcpy(&the_bpf_header,
267 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer
268 1.1 fredette + interface_bpf->_ndbootd_interface_bpf_buffer_offset,
269 1.1 fredette sizeof(the_bpf_header));
270 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer_offset += the_bpf_header.bh_hdrlen;
271 1.1 fredette
272 1.1 fredette /* if we're missing some part of the packet: */
273 1.1 fredette if (the_bpf_header.bh_caplen != the_bpf_header.bh_datalen
274 1.1 fredette || ((interface_bpf->_ndbootd_interface_bpf_buffer_offset + the_bpf_header.bh_datalen)
275 1.1 fredette > interface_bpf->_ndbootd_interface_bpf_buffer_end)) {
276 1.1 fredette _NDBOOTD_DEBUG((fp, "bpf: flushed truncated BPF packet"));
277 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer_offset += the_bpf_header.bh_datalen;
278 1.1 fredette continue;
279 1.1 fredette }
280 1.1 fredette /* silently ignore packets that don't even have Ethernet
281 1.1 fredette * headers, and those packets that we transmitted: */
282 1.1 fredette if (the_bpf_header.bh_datalen < sizeof(struct ether_header)
283 1.1 fredette || !memcmp(((struct ether_header *)
284 1.1 fredette (interface_bpf->_ndbootd_interface_bpf_buffer
285 1.1 fredette + interface_bpf->_ndbootd_interface_bpf_buffer_offset))->ether_shost,
286 1.1 fredette interface->ndbootd_interface_ether,
287 1.1 fredette ETHER_ADDR_LEN)) {
288 1.1 fredette /* silently ignore packets from us: */
289 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer_offset += the_bpf_header.bh_datalen;
290 1.1 fredette continue;
291 1.1 fredette }
292 1.1 fredette /* if the caller hasn't provided a large enough buffer: */
293 1.1 fredette if (packet_buffer_size < the_bpf_header.bh_datalen) {
294 1.1 fredette errno = EIO;
295 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer_offset += the_bpf_header.bh_datalen;
296 1.1 fredette return (-1);
297 1.1 fredette }
298 1.1 fredette /* return this captured packet to the user: */
299 1.1 fredette memcpy(packet_buffer,
300 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer
301 1.1 fredette + interface_bpf->_ndbootd_interface_bpf_buffer_offset,
302 1.1 fredette the_bpf_header.bh_datalen);
303 1.1 fredette interface_bpf->_ndbootd_interface_bpf_buffer_offset += the_bpf_header.bh_datalen;
304 1.1 fredette return (the_bpf_header.bh_datalen);
305 1.1 fredette }
306 1.1 fredette /* NOTREACHED */
307 1.1 fredette }
308 1.1 fredette
309 1.1 fredette /* this writes a raw packet: */
310 1.1 fredette int
311 1.1 fredette ndbootd_raw_write(struct ndbootd_interface * interface, void *packet_buffer, size_t packet_buffer_size)
312 1.1 fredette {
313 1.1 fredette return (write(interface->ndbootd_interface_fd, packet_buffer, packet_buffer_size));
314 1.1 fredette }
315