1 /* $NetBSD: pcap-nit.c,v 1.6 2023/08/17 15:18:12 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that: (1) source code distributions 9 * retain the above copyright notice and this paragraph in its entirety, (2) 10 * distributions including binary code include the above copyright notice and 11 * this paragraph in its entirety in the documentation or other materials 12 * provided with the distribution, and (3) all advertising materials mentioning 13 * features or use of this software display the following acknowledgement: 14 * ``This product includes software developed by the University of California, 15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 16 * the University nor the names of its contributors may be used to endorse 17 * or promote products derived from this software without specific prior 18 * written permission. 19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 22 */ 23 24 #include <sys/cdefs.h> 25 __RCSID("$NetBSD: pcap-nit.c,v 1.6 2023/08/17 15:18:12 christos Exp $"); 26 27 #ifdef HAVE_CONFIG_H 28 #include <config.h> 29 #endif 30 31 #include <sys/types.h> 32 #include <sys/time.h> 33 #include <sys/timeb.h> 34 #include <sys/file.h> 35 #include <sys/ioctl.h> 36 #include <sys/socket.h> 37 38 #include <net/if.h> 39 #include <net/nit.h> 40 41 #include <netinet/in.h> 42 #include <netinet/in_systm.h> 43 #include <netinet/ip.h> 44 #include <netinet/if_ether.h> 45 #include <netinet/ip_var.h> 46 #include <netinet/udp.h> 47 #include <netinet/udp_var.h> 48 #include <netinet/tcp.h> 49 #include <netinet/tcpip.h> 50 51 #include <errno.h> 52 #include <stdio.h> 53 54 #include "pcap-int.h" 55 56 #ifdef HAVE_OS_PROTO_H 57 #include "os-proto.h" 58 #endif 59 60 /* 61 * The chunk size for NIT. This is the amount of buffering 62 * done for read calls. 63 */ 64 #define CHUNKSIZE (2*1024) 65 66 /* 67 * The total buffer space used by NIT. 68 */ 69 #define BUFSPACE (4*CHUNKSIZE) 70 71 /* Forwards */ 72 static int nit_setflags(int, int, int, char *); 73 74 /* 75 * Private data for capturing on NIT devices. 76 */ 77 struct pcap_nit { 78 struct pcap_stat stat; 79 }; 80 81 static int 82 pcap_stats_nit(pcap_t *p, struct pcap_stat *ps) 83 { 84 struct pcap_nit *pn = p->priv; 85 86 /* 87 * "ps_recv" counts packets handed to the filter, not packets 88 * that passed the filter. As filtering is done in userland, 89 * this does not include packets dropped because we ran out 90 * of buffer space. 91 * 92 * "ps_drop" presumably counts packets dropped by the socket 93 * because of flow control requirements or resource exhaustion; 94 * it doesn't count packets dropped by the interface driver. 95 * As filtering is done in userland, it counts packets regardless 96 * of whether they would've passed the filter. 97 * 98 * These statistics don't include packets not yet read from the 99 * kernel by libpcap or packets not yet read from libpcap by the 100 * application. 101 */ 102 *ps = pn->stat; 103 return (0); 104 } 105 106 static int 107 pcap_read_nit(pcap_t *p, int cnt, pcap_handler callback, u_char *user) 108 { 109 struct pcap_nit *pn = p->priv; 110 register int cc, n; 111 register u_char *bp, *cp, *ep; 112 register struct nit_hdr *nh; 113 register int caplen; 114 115 cc = p->cc; 116 if (cc == 0) { 117 cc = read(p->fd, (char *)p->buffer, p->bufsize); 118 if (cc < 0) { 119 if (errno == EWOULDBLOCK) 120 return (0); 121 pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf), 122 errno, "pcap_read"); 123 return (-1); 124 } 125 bp = (u_char *)p->buffer; 126 } else 127 bp = p->bp; 128 129 /* 130 * Loop through each packet. The increment expression 131 * rounds up to the next int boundary past the end of 132 * the previous packet. 133 * 134 * This assumes that a single buffer of packets will have 135 * <= INT_MAX packets, so the packet count doesn't overflow. 136 */ 137 n = 0; 138 ep = bp + cc; 139 while (bp < ep) { 140 /* 141 * Has "pcap_breakloop()" been called? 142 * If so, return immediately - if we haven't read any 143 * packets, clear the flag and return -2 to indicate 144 * that we were told to break out of the loop, otherwise 145 * leave the flag set, so that the *next* call will break 146 * out of the loop without having read any packets, and 147 * return the number of packets we've processed so far. 148 */ 149 if (p->break_loop) { 150 if (n == 0) { 151 p->break_loop = 0; 152 return (-2); 153 } else { 154 p->cc = ep - bp; 155 p->bp = bp; 156 return (n); 157 } 158 } 159 160 nh = (struct nit_hdr *)bp; 161 cp = bp + sizeof(*nh); 162 163 switch (nh->nh_state) { 164 165 case NIT_CATCH: 166 break; 167 168 case NIT_NOMBUF: 169 case NIT_NOCLUSTER: 170 case NIT_NOSPACE: 171 pn->stat.ps_drop = nh->nh_dropped; 172 continue; 173 174 case NIT_SEQNO: 175 continue; 176 177 default: 178 snprintf(p->errbuf, sizeof(p->errbuf), 179 "bad nit state %d", nh->nh_state); 180 return (-1); 181 } 182 ++pn->stat.ps_recv; 183 bp += ((sizeof(struct nit_hdr) + nh->nh_datalen + 184 sizeof(int) - 1) & ~(sizeof(int) - 1)); 185 186 caplen = nh->nh_wirelen; 187 if (caplen > p->snapshot) 188 caplen = p->snapshot; 189 if (pcap_filter(p->fcode.bf_insns, cp, nh->nh_wirelen, caplen)) { 190 struct pcap_pkthdr h; 191 h.ts = nh->nh_timestamp; 192 h.len = nh->nh_wirelen; 193 h.caplen = caplen; 194 (*callback)(user, &h, cp); 195 if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) { 196 p->cc = ep - bp; 197 p->bp = bp; 198 return (n); 199 } 200 } 201 } 202 p->cc = 0; 203 return (n); 204 } 205 206 static int 207 pcap_inject_nit(pcap_t *p, const void *buf, int size) 208 { 209 struct sockaddr sa; 210 int ret; 211 212 memset(&sa, 0, sizeof(sa)); 213 strncpy(sa.sa_data, device, sizeof(sa.sa_data)); 214 ret = sendto(p->fd, buf, size, 0, &sa, sizeof(sa)); 215 if (ret == -1) { 216 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE, 217 errno, "send"); 218 return (-1); 219 } 220 return (ret); 221 } 222 223 static int 224 nit_setflags(pcap_t *p) 225 { 226 struct nit_ioc nioc; 227 228 memset(&nioc, 0, sizeof(nioc)); 229 nioc.nioc_typetomatch = NT_ALLTYPES; 230 nioc.nioc_snaplen = p->snapshot; 231 nioc.nioc_bufalign = sizeof(int); 232 nioc.nioc_bufoffset = 0; 233 234 if (p->opt.buffer_size != 0) 235 nioc.nioc_bufspace = p->opt.buffer_size; 236 else { 237 /* Default buffer size */ 238 nioc.nioc_bufspace = BUFSPACE; 239 } 240 241 if (p->opt.immediate) { 242 /* 243 * XXX - will this cause packets to be delivered immediately? 244 * XXX - given that this is for SunOS prior to 4.0, do 245 * we care? 246 */ 247 nioc.nioc_chunksize = 0; 248 } else 249 nioc.nioc_chunksize = CHUNKSIZE; 250 if (p->opt.timeout != 0) { 251 nioc.nioc_flags |= NF_TIMEOUT; 252 nioc.nioc_timeout.tv_sec = p->opt.timeout / 1000; 253 nioc.nioc_timeout.tv_usec = (p->opt.timeout * 1000) % 1000000; 254 } 255 if (p->opt.promisc) 256 nioc.nioc_flags |= NF_PROMISC; 257 258 if (ioctl(p->fd, SIOCSNIT, &nioc) < 0) { 259 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE, 260 errno, "SIOCSNIT"); 261 return (-1); 262 } 263 return (0); 264 } 265 266 static int 267 pcap_activate_nit(pcap_t *p) 268 { 269 int fd; 270 struct sockaddr_nit snit; 271 272 if (p->opt.rfmon) { 273 /* 274 * No monitor mode on SunOS 3.x or earlier (no 275 * Wi-Fi *devices* for the hardware that supported 276 * them!). 277 */ 278 return (PCAP_ERROR_RFMON_NOTSUP); 279 } 280 281 /* 282 * Turn a negative snapshot value (invalid), a snapshot value of 283 * 0 (unspecified), or a value bigger than the normal maximum 284 * value, into the maximum allowed value. 285 * 286 * If some application really *needs* a bigger snapshot 287 * length, we should just increase MAXIMUM_SNAPLEN. 288 */ 289 if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN) 290 p->snapshot = MAXIMUM_SNAPLEN; 291 292 if (p->snapshot < 96) 293 /* 294 * NIT requires a snapshot length of at least 96. 295 */ 296 p->snapshot = 96; 297 298 memset(p, 0, sizeof(*p)); 299 p->fd = fd = socket(AF_NIT, SOCK_RAW, NITPROTO_RAW); 300 if (fd < 0) { 301 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE, 302 errno, "socket"); 303 goto bad; 304 } 305 snit.snit_family = AF_NIT; 306 (void)strncpy(snit.snit_ifname, p->opt.device, NITIFSIZ); 307 308 if (bind(fd, (struct sockaddr *)&snit, sizeof(snit))) { 309 /* 310 * XXX - there's probably a particular bind error that 311 * means "there's no such device" and a particular bind 312 * error that means "that device doesn't support NIT"; 313 * they might be the same error, if they both end up 314 * meaning "NIT doesn't know about that device". 315 */ 316 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE, 317 errno, "bind: %s", snit.snit_ifname); 318 goto bad; 319 } 320 if (nit_setflags(p) < 0) 321 goto bad; 322 323 /* 324 * NIT supports only ethernets. 325 */ 326 p->linktype = DLT_EN10MB; 327 328 p->bufsize = BUFSPACE; 329 p->buffer = malloc(p->bufsize); 330 if (p->buffer == NULL) { 331 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE, 332 errno, "malloc"); 333 goto bad; 334 } 335 336 /* 337 * "p->fd" is a socket, so "select()" should work on it. 338 */ 339 p->selectable_fd = p->fd; 340 341 /* 342 * This is (presumably) a real Ethernet capture; give it a 343 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so 344 * that an application can let you choose it, in case you're 345 * capturing DOCSIS traffic that a Cisco Cable Modem 346 * Termination System is putting out onto an Ethernet (it 347 * doesn't put an Ethernet header onto the wire, it puts raw 348 * DOCSIS frames out on the wire inside the low-level 349 * Ethernet framing). 350 */ 351 p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); 352 /* 353 * If that fails, just leave the list empty. 354 */ 355 if (p->dlt_list != NULL) { 356 p->dlt_list[0] = DLT_EN10MB; 357 p->dlt_list[1] = DLT_DOCSIS; 358 p->dlt_count = 2; 359 } 360 361 p->read_op = pcap_read_nit; 362 p->inject_op = pcap_inject_nit; 363 p->setfilter_op = install_bpf_program; /* no kernel filtering */ 364 p->setdirection_op = NULL; /* Not implemented. */ 365 p->set_datalink_op = NULL; /* can't change data link type */ 366 p->getnonblock_op = pcap_getnonblock_fd; 367 p->setnonblock_op = pcap_setnonblock_fd; 368 p->stats_op = pcap_stats_nit; 369 370 return (0); 371 bad: 372 pcap_cleanup_live_common(p); 373 return (PCAP_ERROR); 374 } 375 376 pcap_t * 377 pcap_create_interface(const char *device _U_, char *ebuf) 378 { 379 pcap_t *p; 380 381 p = PCAP_CREATE_COMMON(ebuf, struct pcap_nit); 382 if (p == NULL) 383 return (NULL); 384 385 p->activate_op = pcap_activate_nit; 386 return (p); 387 } 388 389 /* 390 * XXX - there's probably a particular bind error that means "that device 391 * doesn't support NIT"; if so, we should try a bind and use that. 392 */ 393 static int 394 can_be_bound(const char *name _U_) 395 { 396 return (1); 397 } 398 399 static int 400 get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_) 401 { 402 /* 403 * Nothing we can do. 404 * XXX - is there a way to find out whether an adapter has 405 * something plugged into it? 406 */ 407 return (0); 408 } 409 410 int 411 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf) 412 { 413 return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound, 414 get_if_flags)); 415 } 416 417 /* 418 * Libpcap version string. 419 */ 420 const char * 421 pcap_lib_version(void) 422 { 423 return (PCAP_VERSION_STRING); 424 } 425