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8bc98059 PJ |
1 | /* |
2 | * IS-IS Rout(e)ing protocol - isis_bpf.c | |
3 | * | |
4 | * Copyright (C) 2001,2002 Sampo Saaristo | |
5 | * Tampere University of Technology | |
6 | * Institute of Communications Engineering | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify it | |
9 | * under the terms of the GNU General Public Licenseas published by the Free | |
10 | * Software Foundation; either version 2 of the License, or (at your option) | |
11 | * any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful,but WITHOUT | |
14 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
16 | * more details. | |
17 | ||
18 | * You should have received a copy of the GNU General Public License along | |
19 | * with this program; if not, write to the Free Software Foundation, Inc., | |
20 | * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
21 | */ | |
22 | ||
23 | #include <zebra.h> | |
24 | #include <net/if.h> | |
25 | #include <netinet/if_ether.h> | |
26 | #include <sys/time.h> | |
27 | #include <sys/ioctl.h> | |
28 | #include <net/bpf.h> | |
29 | ||
30 | #include "log.h" | |
31 | #include "stream.h" | |
32 | #include "if.h" | |
33 | ||
34 | #include "isisd/dict.h" | |
35 | #include "isisd/include-netbsd/iso.h" | |
36 | #include "isisd/isis_constants.h" | |
37 | #include "isisd/isis_common.h" | |
38 | #include "isisd/isis_circuit.h" | |
39 | #include "isisd/isis_flags.h" | |
40 | #include "isisd/isisd.h" | |
41 | #include "isisd/isis_constants.h" | |
42 | #include "isisd/isis_circuit.h" | |
43 | #include "isisd/isis_network.h" | |
44 | ||
45 | #include "privs.h" | |
46 | ||
47 | extern struct zebra_privs_t isisd_privs; | |
48 | ||
49 | struct bpf_insn llcfilter[] = { | |
50 | BPF_STMT (BPF_LD + BPF_B + BPF_ABS, ETHER_HDR_LEN), /* check first byte */ | |
51 | BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ISO_SAP, 0, 5), | |
52 | BPF_STMT (BPF_LD + BPF_B + BPF_ABS, ETHER_HDR_LEN + 1), | |
53 | BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ISO_SAP, 0, 3), /* check second byte */ | |
54 | BPF_STMT (BPF_LD + BPF_B + BPF_ABS, ETHER_HDR_LEN + 2), | |
55 | BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, 0x03, 0, 1), /* check third byte */ | |
56 | BPF_STMT (BPF_RET + BPF_K, (u_int) - 1), | |
57 | BPF_STMT (BPF_RET + BPF_K, 0) | |
58 | }; | |
59 | int readblen = 0; | |
60 | u_char *readbuff = NULL; | |
61 | ||
62 | /* | |
63 | * Table 9 - Architectural constants for use with ISO 8802 subnetworks | |
64 | * ISO 10589 - 8.4.8 | |
65 | */ | |
66 | ||
67 | u_char ALL_L1_ISS[6] = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x14 }; | |
68 | u_char ALL_L2_ISS[6] = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x15 }; | |
69 | u_char ALL_ISS[6] = { 0x09, 0x00, 0x2B, 0x00, 0x00, 0x05 }; | |
70 | u_char ALL_ESS[6] = { 0x09, 0x00, 0x2B, 0x00, 0x00, 0x04 }; | |
71 | ||
72 | static char sock_buff[8192]; | |
73 | ||
74 | static int | |
75 | open_bpf_dev (struct isis_circuit *circuit) | |
76 | { | |
77 | int i = 0, fd; | |
78 | char bpfdev[128]; | |
79 | struct ifreq ifr; | |
80 | u_int16_t blen; | |
81 | int true = 1, false = 0; | |
82 | struct timeval timeout; | |
83 | struct bpf_program bpf_prog; | |
84 | ||
85 | do | |
86 | { | |
87 | (void) snprintf (bpfdev, sizeof (bpfdev), "/dev/bpf%d", i++); | |
88 | fd = open (bpfdev, O_RDWR); | |
89 | } | |
90 | while (fd < 0 && errno == EBUSY); | |
91 | ||
92 | if (fd < 0) | |
93 | { | |
94 | zlog_warn ("open_bpf_dev(): failed to create bpf socket: %s", | |
95 | safe_strerror (errno)); | |
96 | return ISIS_WARNING; | |
97 | } | |
98 | ||
99 | zlog_debug ("Opened BPF device %s", bpfdev); | |
100 | ||
101 | memcpy (ifr.ifr_name, circuit->interface->name, sizeof (ifr.ifr_name)); | |
102 | if (ioctl (fd, BIOCSETIF, (caddr_t) & ifr) < 0) | |
103 | { | |
104 | zlog_warn ("open_bpf_dev(): failed to bind to interface: %s", | |
105 | safe_strerror (errno)); | |
106 | return ISIS_WARNING; | |
107 | } | |
108 | ||
109 | if (ioctl (fd, BIOCGBLEN, (caddr_t) & blen) < 0) | |
110 | { | |
111 | zlog_warn ("failed to get BPF buffer len"); | |
112 | blen = circuit->interface->mtu; | |
113 | } | |
114 | ||
115 | readblen = blen; | |
116 | ||
117 | if (readbuff == NULL) | |
118 | readbuff = malloc (blen); | |
119 | ||
120 | zlog_debug ("BPF buffer len = %u", blen); | |
121 | ||
122 | /* BPF(4): reads return immediately upon packet reception. | |
123 | * Otherwise, a read will block until either the kernel | |
124 | * buffer becomes full or a timeout occurs. | |
125 | */ | |
126 | if (ioctl (fd, BIOCIMMEDIATE, (caddr_t) & true) < 0) | |
127 | { | |
128 | zlog_warn ("failed to set BPF dev to immediate mode"); | |
129 | } | |
130 | ||
131 | #ifdef BIOCSSEESENT | |
132 | /* | |
133 | * We want to see only incoming packets | |
134 | */ | |
135 | if (ioctl (fd, BIOCSSEESENT, (caddr_t) & false) < 0) | |
136 | { | |
137 | zlog_warn ("failed to set BPF dev to incoming only mode"); | |
138 | } | |
139 | #endif | |
140 | ||
141 | /* | |
142 | * ...but all of them | |
143 | */ | |
144 | if (ioctl (fd, BIOCPROMISC, (caddr_t) & true) < 0) | |
145 | { | |
146 | zlog_warn ("failed to set BPF dev to promiscuous mode"); | |
147 | } | |
148 | ||
149 | /* | |
150 | * If the buffer length is smaller than our mtu, lets try to increase it | |
151 | */ | |
152 | if (blen < circuit->interface->mtu) | |
153 | { | |
154 | if (ioctl (fd, BIOCSBLEN, &circuit->interface->mtu) < 0) | |
155 | { | |
156 | zlog_warn ("failed to set BPF buffer len (%u to %u)", blen, | |
157 | circuit->interface->mtu); | |
158 | } | |
159 | } | |
160 | ||
161 | /* | |
162 | * Set a timeout parameter - hope this helps select() | |
163 | */ | |
164 | timeout.tv_sec = 600; | |
165 | timeout.tv_usec = 0; | |
166 | if (ioctl (fd, BIOCSRTIMEOUT, (caddr_t) & timeout) < 0) | |
167 | { | |
168 | zlog_warn ("failed to set BPF device timeout"); | |
169 | } | |
170 | ||
171 | /* | |
172 | * And set the filter | |
173 | */ | |
174 | memset (&bpf_prog, 0, sizeof (struct bpf_program)); | |
175 | bpf_prog.bf_len = 8; | |
176 | bpf_prog.bf_insns = &(llcfilter[0]); | |
177 | if (ioctl (fd, BIOCSETF, (caddr_t) & bpf_prog) < 0) | |
178 | { | |
179 | zlog_warn ("open_bpf_dev(): failed to install filter: %s", | |
180 | safe_strerror (errno)); | |
181 | return ISIS_WARNING; | |
182 | } | |
183 | ||
184 | assert (fd > 0); | |
185 | ||
186 | circuit->fd = fd; | |
187 | ||
188 | return ISIS_OK; | |
189 | } | |
190 | ||
191 | /* | |
192 | * Create the socket and set the tx/rx funcs | |
193 | */ | |
194 | int | |
195 | isis_sock_init (struct isis_circuit *circuit) | |
196 | { | |
197 | int retval = ISIS_OK; | |
198 | ||
199 | if (isisd_privs.change (ZPRIVS_RAISE)) | |
200 | zlog_err ("%s: could not raise privs, %s", __func__, safe_strerror (errno)); | |
201 | ||
202 | retval = open_bpf_dev (circuit); | |
203 | ||
204 | if (retval != ISIS_OK) | |
205 | { | |
206 | zlog_warn ("%s: could not initialize the socket", __func__); | |
207 | goto end; | |
208 | } | |
209 | ||
210 | if (circuit->circ_type == CIRCUIT_T_BROADCAST) | |
211 | { | |
212 | circuit->tx = isis_send_pdu_bcast; | |
213 | circuit->rx = isis_recv_pdu_bcast; | |
214 | } | |
215 | else if (circuit->circ_type == CIRCUIT_T_P2P) | |
216 | { | |
217 | circuit->tx = isis_send_pdu_p2p; | |
218 | circuit->rx = isis_recv_pdu_p2p; | |
219 | } | |
220 | else | |
221 | { | |
222 | zlog_warn ("isis_sock_init(): unknown circuit type"); | |
223 | retval = ISIS_WARNING; | |
224 | goto end; | |
225 | } | |
226 | ||
227 | end: | |
228 | if (isisd_privs.change (ZPRIVS_LOWER)) | |
229 | zlog_err ("%s: could not lower privs, %s", __func__, safe_strerror (errno)); | |
230 | ||
231 | return retval; | |
232 | } | |
233 | ||
234 | int | |
235 | isis_recv_pdu_bcast (struct isis_circuit *circuit, u_char * ssnpa) | |
236 | { | |
237 | int bytesread = 0, bytestoread, offset, one = 1; | |
238 | struct bpf_hdr *bpf_hdr; | |
239 | ||
240 | assert (circuit->fd > 0); | |
241 | ||
242 | if (ioctl (circuit->fd, FIONREAD, (caddr_t) & bytestoread) < 0) | |
243 | { | |
244 | zlog_warn ("ioctl() FIONREAD failed: %s", safe_strerror (errno)); | |
245 | } | |
246 | ||
247 | if (bytestoread) | |
248 | { | |
249 | bytesread = read (circuit->fd, readbuff, readblen); | |
250 | } | |
251 | if (bytesread < 0) | |
252 | { | |
253 | zlog_warn ("isis_recv_pdu_bcast(): read() failed: %s", | |
254 | safe_strerror (errno)); | |
255 | return ISIS_WARNING; | |
256 | } | |
257 | ||
258 | if (bytesread == 0) | |
259 | return ISIS_WARNING; | |
260 | ||
261 | bpf_hdr = (struct bpf_hdr *) readbuff; | |
262 | ||
263 | assert (bpf_hdr->bh_caplen == bpf_hdr->bh_datalen); | |
264 | ||
265 | offset = bpf_hdr->bh_hdrlen + LLC_LEN + ETHER_HDR_LEN; | |
266 | ||
267 | /* then we lose the BPF, LLC and ethernet headers */ | |
268 | stream_write (circuit->rcv_stream, readbuff + offset, | |
269 | bpf_hdr->bh_caplen - LLC_LEN - ETHER_HDR_LEN); | |
270 | stream_set_getp (circuit->rcv_stream, 0); | |
271 | ||
272 | memcpy (ssnpa, readbuff + bpf_hdr->bh_hdrlen + ETHER_ADDR_LEN, | |
273 | ETHER_ADDR_LEN); | |
274 | ||
275 | if (ioctl (circuit->fd, BIOCFLUSH, &one) < 0) | |
276 | zlog_warn ("Flushing failed: %s", safe_strerror (errno)); | |
277 | ||
278 | return ISIS_OK; | |
279 | } | |
280 | ||
281 | int | |
282 | isis_recv_pdu_p2p (struct isis_circuit *circuit, u_char * ssnpa) | |
283 | { | |
284 | int bytesread; | |
285 | ||
286 | bytesread = stream_read (circuit->rcv_stream, circuit->fd, | |
287 | circuit->interface->mtu); | |
288 | ||
289 | if (bytesread < 0) | |
290 | { | |
291 | zlog_warn ("isis_recv_pdu_p2p(): read () failed: %s", safe_strerror (errno)); | |
292 | return ISIS_WARNING; | |
293 | } | |
294 | ||
295 | return ISIS_OK; | |
296 | } | |
297 | ||
298 | int | |
299 | isis_send_pdu_bcast (struct isis_circuit *circuit, int level) | |
300 | { | |
301 | struct ether_header *eth; | |
302 | int written; | |
303 | ||
304 | stream_set_getp (circuit->snd_stream, 0); | |
305 | ||
306 | /* | |
307 | * First the eth header | |
308 | */ | |
309 | eth = (struct ether_header *) sock_buff; | |
310 | if (level == 1) | |
311 | memcpy (eth->ether_dhost, ALL_L1_ISS, ETHER_ADDR_LEN); | |
312 | else | |
313 | memcpy (eth->ether_dhost, ALL_L2_ISS, ETHER_ADDR_LEN); | |
314 | memcpy (eth->ether_shost, circuit->u.bc.snpa, ETHER_ADDR_LEN); | |
315 | eth->ether_type = htons (stream_get_endp (circuit->snd_stream) + LLC_LEN); | |
316 | ||
317 | /* | |
318 | * Then the LLC | |
319 | */ | |
320 | sock_buff[ETHER_HDR_LEN] = ISO_SAP; | |
321 | sock_buff[ETHER_HDR_LEN + 1] = ISO_SAP; | |
322 | sock_buff[ETHER_HDR_LEN + 2] = 0x03; | |
323 | ||
324 | /* then we copy the data */ | |
325 | memcpy (sock_buff + (LLC_LEN + ETHER_HDR_LEN), circuit->snd_stream->data, | |
326 | stream_get_endp (circuit->snd_stream)); | |
327 | ||
328 | /* now we can send this */ | |
329 | written = write (circuit->fd, sock_buff, | |
330 | stream_get_endp (circuit->snd_stream) | |
331 | + LLC_LEN + ETHER_HDR_LEN); | |
332 | ||
333 | return ISIS_OK; | |
334 | } | |
335 | ||
336 | int | |
337 | isis_send_pdu_p2p (struct isis_circuit *circuit, int level) | |
338 | { | |
339 | return ISIS_OK; | |
340 | } |