1 /* 2 * Copyright (c) 2006 Paolo Abeni (Italy) 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote 15 * products derived from this software without specific prior written 16 * permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * 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 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 * USB sniffing API implementation for Linux platform 31 * By Paolo Abeni <paolo.abeni@email.it> 32 * Modifications: Kris Katterjohn <katterjohn@gmail.com> 33 * 34 */ 35 #ifndef lint 36 static const char rcsid[] _U_ = 37 "@(#) $Header: /tcpdump/master/libpcap/pcap-usb-linux.c,v 1.16.2.8 2008-04-14 21:06:29 guy Exp $ (LBL)"; 38 #endif 39 40 #ifdef HAVE_CONFIG_H 41 #include "config.h" 42 #endif 43 44 #include "pcap-int.h" 45 #include "pcap-usb-linux.h" 46 #include "pcap/usb.h" 47 48 #ifdef NEED_STRERROR_H 49 #include "strerror.h" 50 #endif 51 52 #include <ctype.h> 53 #include <errno.h> 54 #include <stdlib.h> 55 #include <unistd.h> 56 #include <fcntl.h> 57 #include <string.h> 58 #include <dirent.h> 59 #include <byteswap.h> 60 #include <netinet/in.h> 61 #include <sys/ioctl.h> 62 #include <sys/mman.h> 63 64 #define USB_IFACE "usb" 65 #define USB_TEXT_DIR "/sys/kernel/debug/usbmon" 66 #define USB_BUS_DIR "/proc/bus/usb" 67 #define USB_LINE_LEN 4096 68 69 70 #define PIPE_IN 0x80 71 #define PIPE_ISOCHRONOUS 0 72 #define PIPE_INTERRUPT 1 73 #define PIPE_CONTROL 2 74 #define PIPE_BULK 3 75 76 #if __BYTE_ORDER == __LITTLE_ENDIAN 77 #define htols(s) s 78 #define htoll(l) l 79 #define htol64(ll) ll 80 #else 81 #define htols(s) bswap_16(s) 82 #define htoll(l) bswap_32(l) 83 #define htol64(ll) bswap_64(ll) 84 #endif 85 86 struct mon_bin_stats { 87 u_int32_t queued; 88 u_int32_t dropped; 89 }; 90 91 struct mon_bin_get { 92 pcap_usb_header *hdr; 93 void *data; 94 size_t data_len; /* Length of data (can be zero) */ 95 }; 96 97 struct mon_bin_mfetch { 98 int32_t *offvec; /* Vector of events fetched */ 99 int32_t nfetch; /* Number of events to fetch (out: fetched) */ 100 int32_t nflush; /* Number of events to flush */ 101 }; 102 103 #define MON_IOC_MAGIC 0x92 104 105 #define MON_IOCQ_URB_LEN _IO(MON_IOC_MAGIC, 1) 106 #define MON_IOCX_URB _IOWR(MON_IOC_MAGIC, 2, struct mon_bin_hdr) 107 #define MON_IOCG_STATS _IOR(MON_IOC_MAGIC, 3, struct mon_bin_stats) 108 #define MON_IOCT_RING_SIZE _IO(MON_IOC_MAGIC, 4) 109 #define MON_IOCQ_RING_SIZE _IO(MON_IOC_MAGIC, 5) 110 #define MON_IOCX_GET _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get) 111 #define MON_IOCX_MFETCH _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch) 112 #define MON_IOCH_MFLUSH _IO(MON_IOC_MAGIC, 8) 113 114 #define MON_BIN_SETUP 0x1 /* setup hdr is present*/ 115 #define MON_BIN_SETUP_ZERO 0x2 /* setup buffer is not available */ 116 #define MON_BIN_DATA_ZERO 0x4 /* data buffer is not available */ 117 #define MON_BIN_ERROR 0x8 118 119 /* forward declaration */ 120 static int usb_activate(pcap_t *); 121 static int usb_stats_linux(pcap_t *, struct pcap_stat *); 122 static int usb_stats_linux_bin(pcap_t *, struct pcap_stat *); 123 static int usb_read_linux(pcap_t *, int , pcap_handler , u_char *); 124 static int usb_read_linux_bin(pcap_t *, int , pcap_handler , u_char *); 125 static int usb_read_linux_mmap(pcap_t *, int , pcap_handler , u_char *); 126 static int usb_inject_linux(pcap_t *, const void *, size_t); 127 static int usb_setfilter_linux(pcap_t *, struct bpf_program *); 128 static int usb_setdirection_linux(pcap_t *, pcap_direction_t); 129 static void usb_cleanup_linux_mmap(pcap_t *); 130 131 /* facility to add an USB device to the device list*/ 132 static int 133 usb_dev_add(pcap_if_t** alldevsp, int n, char *err_str) 134 { 135 char dev_name[10]; 136 char dev_descr[30]; 137 snprintf(dev_name, 10, USB_IFACE"%d", n); 138 snprintf(dev_descr, 30, "USB bus number %d", n); 139 140 if (pcap_add_if(alldevsp, dev_name, 0, 141 dev_descr, err_str) < 0) 142 return -1; 143 return 0; 144 } 145 146 int 147 usb_platform_finddevs(pcap_if_t **alldevsp, char *err_str) 148 { 149 struct dirent* data; 150 int ret = 0; 151 DIR* dir; 152 153 /* scan procfs usb bus directory */ 154 dir = opendir(USB_BUS_DIR); 155 if (!dir) return 0; 156 while ((ret == 0) && ((data = readdir(dir)) != 0)) { 157 int n; 158 char* name = data->d_name; 159 int len = strlen(name); 160 161 /* if this file name does not end with a number it's not of our interest */ 162 if ((len < 1) || !isdigit(name[--len])) 163 continue; 164 while (isdigit(name[--len])); 165 if (sscanf(&name[len+1], "%d", &n) != 1) 166 continue; 167 168 ret = usb_dev_add(alldevsp, n, err_str); 169 } 170 171 closedir(dir); 172 return ret; 173 } 174 175 static 176 int usb_mmap(pcap_t* handle) 177 { 178 int len = ioctl(handle->fd, MON_IOCQ_RING_SIZE); 179 if (len < 0) 180 return 0; 181 182 handle->buffer = mmap(0, len, PROT_READ, MAP_SHARED, handle->fd, 0); 183 return handle->buffer != MAP_FAILED; 184 } 185 186 pcap_t * 187 usb_create(const char *device, char *ebuf) 188 { 189 pcap_t *p; 190 191 p = pcap_create_common(device, ebuf); 192 if (p == NULL) 193 return (NULL); 194 195 p->activate_op = usb_activate; 196 return (p); 197 } 198 199 static int 200 usb_activate(pcap_t* handle) 201 { 202 char full_path[USB_LINE_LEN]; 203 204 /* Initialize some components of the pcap structure. */ 205 handle->bufsize = handle->snapshot; 206 handle->offset = 0; 207 handle->linktype = DLT_USB_LINUX; 208 209 handle->inject_op = usb_inject_linux; 210 handle->setfilter_op = usb_setfilter_linux; 211 handle->setdirection_op = usb_setdirection_linux; 212 handle->set_datalink_op = NULL; /* can't change data link type */ 213 handle->getnonblock_op = pcap_getnonblock_fd; 214 handle->setnonblock_op = pcap_setnonblock_fd; 215 216 /*get usb bus index from device name */ 217 if (sscanf(handle->opt.source, USB_IFACE"%d", &handle->md.ifindex) != 1) 218 { 219 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 220 "Can't get USB bus index from %s", handle->opt.source); 221 return PCAP_ERROR; 222 } 223 224 /*now select the read method: try to open binary interface */ 225 snprintf(full_path, USB_LINE_LEN, LINUX_USB_MON_DEV"%d", handle->md.ifindex); 226 handle->fd = open(full_path, O_RDONLY, 0); 227 if (handle->fd >= 0) 228 { 229 if (handle->opt.rfmon) { 230 /* 231 * Monitor mode doesn't apply to USB devices. 232 */ 233 return PCAP_ERROR_RFMON_NOTSUP; 234 } 235 236 /* binary api is available, try to use fast mmap access */ 237 if (usb_mmap(handle)) { 238 handle->stats_op = usb_stats_linux_bin; 239 handle->read_op = usb_read_linux_mmap; 240 handle->cleanup_op = usb_cleanup_linux_mmap; 241 242 /* 243 * "handle->fd" is a real file, so "select()" and 244 * "poll()" work on it. 245 */ 246 handle->selectable_fd = handle->fd; 247 return 0; 248 } 249 250 /* can't mmap, use plain binary interface access */ 251 handle->stats_op = usb_stats_linux_bin; 252 handle->read_op = usb_read_linux_bin; 253 } 254 else { 255 /*Binary interface not available, try open text interface */ 256 snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR"/%dt", handle->md.ifindex); 257 handle->fd = open(full_path, O_RDONLY, 0); 258 if (handle->fd < 0) 259 { 260 /* no more fallback, give it up*/ 261 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 262 "Can't open USB bus file %s: %s", full_path, strerror(errno)); 263 return PCAP_ERROR; 264 } 265 handle->stats_op = usb_stats_linux; 266 handle->read_op = usb_read_linux; 267 } 268 269 if (handle->opt.rfmon) { 270 /* 271 * Monitor mode doesn't apply to USB devices. 272 */ 273 return PCAP_ERROR_RFMON_NOTSUP; 274 } 275 276 /* 277 * "handle->fd" is a real file, so "select()" and "poll()" 278 * work on it. 279 */ 280 handle->selectable_fd = handle->fd; 281 282 /* for plain binary access and text access we need to allocate the read 283 * buffer */ 284 handle->buffer = malloc(handle->bufsize); 285 if (!handle->buffer) { 286 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 287 "malloc: %s", pcap_strerror(errno)); 288 return PCAP_ERROR; 289 } 290 return 0; 291 } 292 293 static inline int 294 ascii_to_int(char c) 295 { 296 return c < 'A' ? c- '0': ((c<'a') ? c - 'A' + 10: c-'a'+10); 297 } 298 299 /* 300 * see <linux-kernel-source>/Documentation/usb/usbmon.txt and 301 * <linux-kernel-source>/drivers/usb/mon/mon_text.c for urb string 302 * format description 303 */ 304 static int 305 usb_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) 306 { 307 /* see: 308 * /usr/src/linux/Documentation/usb/usbmon.txt 309 * for message format 310 */ 311 unsigned timestamp; 312 int tag, cnt, ep_num, dev_addr, dummy, ret, urb_len, data_len; 313 char etype, pipeid1, pipeid2, status[16], urb_tag, line[USB_LINE_LEN]; 314 char *string = line; 315 u_char * rawdata = handle->buffer; 316 struct pcap_pkthdr pkth; 317 pcap_usb_header* uhdr = (pcap_usb_header*)handle->buffer; 318 u_char urb_transfer=0; 319 int incoming=0; 320 321 /* ignore interrupt system call errors */ 322 do { 323 ret = read(handle->fd, line, USB_LINE_LEN - 1); 324 if (handle->break_loop) 325 { 326 handle->break_loop = 0; 327 return -2; 328 } 329 } while ((ret == -1) && (errno == EINTR)); 330 if (ret < 0) 331 { 332 if (errno == EAGAIN) 333 return 0; /* no data there */ 334 335 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 336 "Can't read from fd %d: %s", handle->fd, strerror(errno)); 337 return -1; 338 } 339 340 /* read urb header; %n argument may increment return value, but it's 341 * not mandatory, so does not count on it*/ 342 string[ret] = 0; 343 ret = sscanf(string, "%x %d %c %c%c:%d:%d %s%n", &tag, ×tamp, &etype, 344 &pipeid1, &pipeid2, &dev_addr, &ep_num, status, 345 &cnt); 346 if (ret < 8) 347 { 348 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 349 "Can't parse USB bus message '%s', too few tokens (expected 8 got %d)", 350 string, ret); 351 return -1; 352 } 353 uhdr->id = tag; 354 uhdr->endpoint_number = ep_num; 355 uhdr->device_address = dev_addr; 356 uhdr->bus_id = handle->md.ifindex; 357 uhdr->status = 0; 358 string += cnt; 359 360 /* don't use usbmon provided timestamp, since it have low precision*/ 361 if (gettimeofday(&pkth.ts, NULL) < 0) 362 { 363 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 364 "Can't get timestamp for message '%s' %d:%s", 365 string, errno, strerror(errno)); 366 return -1; 367 } 368 uhdr->ts_sec = pkth.ts.tv_sec; 369 uhdr->ts_usec = pkth.ts.tv_usec; 370 371 /* parse endpoint information */ 372 if (pipeid1 == 'C') 373 urb_transfer = URB_CONTROL; 374 else if (pipeid1 == 'Z') 375 urb_transfer = URB_ISOCHRONOUS; 376 else if (pipeid1 == 'I') 377 urb_transfer = URB_INTERRUPT; 378 else if (pipeid1 == 'B') 379 urb_transfer = URB_BULK; 380 if (pipeid2 == 'i') { 381 urb_transfer |= URB_TRANSFER_IN; 382 incoming = 1; 383 } 384 if (etype == 'C') 385 incoming = !incoming; 386 387 /* direction check*/ 388 if (incoming) 389 { 390 if (handle->direction == PCAP_D_OUT) 391 return 0; 392 } 393 else 394 if (handle->direction == PCAP_D_IN) 395 return 0; 396 uhdr->event_type = etype; 397 uhdr->transfer_type = urb_transfer; 398 pkth.caplen = sizeof(pcap_usb_header); 399 rawdata += sizeof(pcap_usb_header); 400 401 /* check if this is a setup packet */ 402 ret = sscanf(status, "%d", &dummy); 403 if (ret != 1) 404 { 405 /* this a setup packet, setup data can be filled with underscore if 406 * usbmon has not been able to read them, so we must parse this fields as 407 * strings */ 408 pcap_usb_setup* shdr; 409 char str1[3], str2[3], str3[5], str4[5], str5[5]; 410 ret = sscanf(string, "%s %s %s %s %s%n", str1, str2, str3, str4, 411 str5, &cnt); 412 if (ret < 5) 413 { 414 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 415 "Can't parse USB bus message '%s', too few tokens (expected 5 got %d)", 416 string, ret); 417 return -1; 418 } 419 string += cnt; 420 421 /* try to convert to corresponding integer */ 422 shdr = &uhdr->setup; 423 shdr->bmRequestType = strtoul(str1, 0, 16); 424 shdr->bRequest = strtoul(str2, 0, 16); 425 shdr->wValue = htols(strtoul(str3, 0, 16)); 426 shdr->wIndex = htols(strtoul(str4, 0, 16)); 427 shdr->wLength = htols(strtoul(str5, 0, 16)); 428 429 uhdr->setup_flag = 0; 430 } 431 else 432 uhdr->setup_flag = 1; 433 434 /* read urb data */ 435 ret = sscanf(string, " %d%n", &urb_len, &cnt); 436 if (ret < 1) 437 { 438 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 439 "Can't parse urb length from '%s'", string); 440 return -1; 441 } 442 string += cnt; 443 444 /* urb tag is not present if urb length is 0, so we can stop here 445 * text parsing */ 446 pkth.len = urb_len+pkth.caplen; 447 uhdr->urb_len = urb_len; 448 uhdr->data_flag = 1; 449 data_len = 0; 450 if (uhdr->urb_len == pkth.caplen) 451 goto got; 452 453 /* check for data presence; data is present if and only if urb tag is '=' */ 454 if (sscanf(string, " %c", &urb_tag) != 1) 455 { 456 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 457 "Can't parse urb tag from '%s'", string); 458 return -1; 459 } 460 461 if (urb_tag != '=') 462 goto got; 463 464 /* skip urb tag and following space */ 465 string += 3; 466 467 /* if we reach this point we got some urb data*/ 468 uhdr->data_flag = 0; 469 470 /* read all urb data; if urb length is greater then the usbmon internal 471 * buffer length used by the kernel to spool the URB, we get only 472 * a partial information. 473 * At least until linux 2.6.17 there is no way to set usbmon intenal buffer 474 * length and default value is 130. */ 475 while ((string[0] != 0) && (string[1] != 0) && (pkth.caplen < handle->snapshot)) 476 { 477 rawdata[0] = ascii_to_int(string[0]) * 16 + ascii_to_int(string[1]); 478 rawdata++; 479 string+=2; 480 if (string[0] == ' ') 481 string++; 482 pkth.caplen++; 483 data_len++; 484 } 485 486 got: 487 uhdr->data_len = data_len; 488 handle->md.packets_read++; 489 if (pkth.caplen > handle->snapshot) 490 pkth.caplen = handle->snapshot; 491 492 callback(user, &pkth, handle->buffer); 493 return 1; 494 } 495 496 static int 497 usb_inject_linux(pcap_t *handle, const void *buf, size_t size) 498 { 499 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on " 500 "USB devices"); 501 return (-1); 502 } 503 504 static int 505 usb_stats_linux(pcap_t *handle, struct pcap_stat *stats) 506 { 507 int dummy, ret, consumed, cnt; 508 char string[USB_LINE_LEN]; 509 char token[USB_LINE_LEN]; 510 char * ptr = string; 511 snprintf(string, USB_LINE_LEN, USB_TEXT_DIR"/%ds", handle->md.ifindex); 512 513 int fd = open(string, O_RDONLY, 0); 514 if (fd < 0) 515 { 516 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 517 "Can't open USB stats file %s: %s", 518 string, strerror(errno)); 519 return -1; 520 } 521 522 /* read stats line */ 523 do { 524 ret = read(fd, string, USB_LINE_LEN-1); 525 } while ((ret == -1) && (errno == EINTR)); 526 close(fd); 527 528 if (ret < 0) 529 { 530 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 531 "Can't read stats from fd %d ", fd); 532 return -1; 533 } 534 string[ret] = 0; 535 536 /* extract info on dropped urbs */ 537 for (consumed=0; consumed < ret; ) { 538 /* from the sscanf man page: 539 * The C standard says: "Execution of a %n directive does 540 * not increment the assignment count returned at the completion 541 * of execution" but the Corrigendum seems to contradict this. 542 * Do not make any assumptions on the effect of %n conversions 543 * on the return value and explicitly check for cnt assignmet*/ 544 cnt = -1; 545 int ntok = sscanf(ptr, "%s%n", token, &cnt); 546 if ((ntok < 1) || (cnt < 0)) 547 break; 548 consumed += cnt; 549 ptr += cnt; 550 if (strcmp(token, "nreaders") == 0) 551 ret = sscanf(ptr, "%d", &stats->ps_drop); 552 else 553 ret = sscanf(ptr, "%d", &dummy); 554 if (ntok != 1) 555 break; 556 consumed += cnt; 557 ptr += cnt; 558 } 559 560 stats->ps_recv = handle->md.packets_read; 561 stats->ps_ifdrop = 0; 562 return 0; 563 } 564 565 static int 566 usb_setfilter_linux(pcap_t *p, struct bpf_program *fp) 567 { 568 return 0; 569 } 570 571 static int 572 usb_setdirection_linux(pcap_t *p, pcap_direction_t d) 573 { 574 p->direction = d; 575 return 0; 576 } 577 578 579 static int 580 usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats) 581 { 582 int ret; 583 struct mon_bin_stats st; 584 ret = ioctl(handle->fd, MON_IOCG_STATS, &st); 585 if (ret < 0) 586 { 587 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 588 "Can't read stats from fd %d:%s ", handle->fd, strerror(errno)); 589 return -1; 590 } 591 592 stats->ps_recv = handle->md.packets_read + st.queued; 593 stats->ps_ifdrop = st.dropped; 594 return 0; 595 } 596 597 /* 598 * see <linux-kernel-source>/Documentation/usb/usbmon.txt and 599 * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI 600 */ 601 static int 602 usb_read_linux_bin(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) 603 { 604 struct mon_bin_get info; 605 int ret; 606 struct pcap_pkthdr pkth; 607 int clen = handle->snapshot - sizeof(pcap_usb_header); 608 609 /* the usb header is going to be part of 'packet' data*/ 610 info.hdr = (pcap_usb_header*) handle->buffer; 611 info.data = handle->buffer + sizeof(pcap_usb_header); 612 info.data_len = clen; 613 614 /* ignore interrupt system call errors */ 615 do { 616 ret = ioctl(handle->fd, MON_IOCX_GET, &info); 617 if (handle->break_loop) 618 { 619 handle->break_loop = 0; 620 return -2; 621 } 622 } while ((ret == -1) && (errno == EINTR)); 623 if (ret < 0) 624 { 625 if (errno == EAGAIN) 626 return 0; /* no data there */ 627 628 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 629 "Can't read from fd %d: %s", handle->fd, strerror(errno)); 630 return -1; 631 } 632 633 /* we can get less that than really captured from kernel, depending on 634 * snaplen, so adjust header accordingly */ 635 if (info.hdr->data_len < clen) 636 clen = info.hdr->data_len; 637 info.hdr->data_len = clen; 638 pkth.caplen = clen + sizeof(pcap_usb_header); 639 pkth.len = info.hdr->urb_len + sizeof(pcap_usb_header); 640 pkth.ts.tv_sec = info.hdr->ts_sec; 641 pkth.ts.tv_usec = info.hdr->ts_usec; 642 643 handle->md.packets_read++; 644 callback(user, &pkth, handle->buffer); 645 return 1; 646 } 647 648 /* 649 * see <linux-kernel-source>/Documentation/usb/usbmon.txt and 650 * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI 651 */ 652 #define VEC_SIZE 32 653 static int 654 usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) 655 { 656 struct mon_bin_mfetch fetch; 657 int32_t vec[VEC_SIZE]; 658 struct pcap_pkthdr pkth; 659 pcap_usb_header* hdr; 660 int nflush = 0; 661 int packets = 0; 662 663 for (;;) { 664 int i, ret; 665 int limit = max_packets - packets; 666 if (limit <= 0) 667 limit = VEC_SIZE; 668 if (limit > VEC_SIZE) 669 limit = VEC_SIZE; 670 671 /* try to fetch as many events as possible*/ 672 fetch.offvec = vec; 673 fetch.nfetch = limit; 674 fetch.nflush = nflush; 675 /* ignore interrupt system call errors */ 676 do { 677 ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch); 678 if (handle->break_loop) 679 { 680 handle->break_loop = 0; 681 return -2; 682 } 683 } while ((ret == -1) && (errno == EINTR)); 684 if (ret < 0) 685 { 686 if (errno == EAGAIN) 687 return 0; /* no data there */ 688 689 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 690 "Can't mfetch fd %d: %s", handle->fd, strerror(errno)); 691 return -1; 692 } 693 694 /* keep track of processed events, we will flush them later */ 695 nflush = fetch.nfetch; 696 for (i=0; i<fetch.nfetch; ++i) { 697 /* discard filler */ 698 hdr = (pcap_usb_header*) &handle->buffer[vec[i]]; 699 if (hdr->event_type == '@') 700 continue; 701 702 /* get packet info from header*/ 703 pkth.caplen = hdr->data_len + sizeof(pcap_usb_header); 704 pkth.len = hdr->urb_len + sizeof(pcap_usb_header); 705 pkth.ts.tv_sec = hdr->ts_sec; 706 pkth.ts.tv_usec = hdr->ts_usec; 707 708 handle->md.packets_read++; 709 callback(user, &pkth, (u_char*) hdr); 710 packets++; 711 } 712 713 /* with max_packets <= 0 we stop afer the first chunk*/ 714 if ((max_packets <= 0) || (packets == max_packets)) 715 break; 716 } 717 718 /* flush pending events*/ 719 ioctl(handle->fd, MON_IOCH_MFLUSH, nflush); 720 return packets; 721 } 722 723 static void 724 usb_cleanup_linux_mmap(pcap_t* handle) 725 { 726 /* buffer must not be freed because it's memory mapped */ 727 /* XXX - does it need to be unmapped? */ 728 handle->buffer = NULL; 729 pcap_cleanup_live_common(handle); 730 } 731