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/*
* Copyright (c) 2006 Paolo Abeni (Italy)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* USB sniffing API implementation for Linux platform
* By Paolo Abeni <paolo.abeni@email.it>
* Modifications: Kris Katterjohn <katterjohn@gmail.com>
*
*/
#ifndef lint
static const char rcsid[] _U_ =
"@(#) $Header: /tcpdump/master/libpcap/pcap-usb-linux.c,v 1.16.2.8 2008-04-14 21:06:29 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "pcap-int.h"
#include "pcap-usb-linux.h"
#include "pcap/usb.h"
#ifdef NEED_STRERROR_H
#include "strerror.h"
#endif
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <dirent.h>
#include <byteswap.h>
#include <netinet/in.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#define USB_IFACE "usb"
#define USB_TEXT_DIR "/sys/kernel/debug/usbmon"
#define USB_BUS_DIR "/proc/bus/usb"
#define USB_LINE_LEN 4096
#define PIPE_IN 0x80
#define PIPE_ISOCHRONOUS 0
#define PIPE_INTERRUPT 1
#define PIPE_CONTROL 2
#define PIPE_BULK 3
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define htols(s) s
#define htoll(l) l
#define htol64(ll) ll
#else
#define htols(s) bswap_16(s)
#define htoll(l) bswap_32(l)
#define htol64(ll) bswap_64(ll)
#endif
struct mon_bin_stats {
u_int32_t queued;
u_int32_t dropped;
};
struct mon_bin_get {
pcap_usb_header *hdr;
void *data;
size_t data_len; /* Length of data (can be zero) */
};
struct mon_bin_mfetch {
int32_t *offvec; /* Vector of events fetched */
int32_t nfetch; /* Number of events to fetch (out: fetched) */
int32_t nflush; /* Number of events to flush */
};
#define MON_IOC_MAGIC 0x92
#define MON_IOCQ_URB_LEN _IO(MON_IOC_MAGIC, 1)
#define MON_IOCX_URB _IOWR(MON_IOC_MAGIC, 2, struct mon_bin_hdr)
#define MON_IOCG_STATS _IOR(MON_IOC_MAGIC, 3, struct mon_bin_stats)
#define MON_IOCT_RING_SIZE _IO(MON_IOC_MAGIC, 4)
#define MON_IOCQ_RING_SIZE _IO(MON_IOC_MAGIC, 5)
#define MON_IOCX_GET _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get)
#define MON_IOCX_MFETCH _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch)
#define MON_IOCH_MFLUSH _IO(MON_IOC_MAGIC, 8)
#define MON_BIN_SETUP 0x1 /* setup hdr is present*/
#define MON_BIN_SETUP_ZERO 0x2 /* setup buffer is not available */
#define MON_BIN_DATA_ZERO 0x4 /* data buffer is not available */
#define MON_BIN_ERROR 0x8
/* forward declaration */
static int usb_activate(pcap_t *);
static int usb_stats_linux(pcap_t *, struct pcap_stat *);
static int usb_stats_linux_bin(pcap_t *, struct pcap_stat *);
static int usb_read_linux(pcap_t *, int , pcap_handler , u_char *);
static int usb_read_linux_bin(pcap_t *, int , pcap_handler , u_char *);
static int usb_read_linux_mmap(pcap_t *, int , pcap_handler , u_char *);
static int usb_inject_linux(pcap_t *, const void *, size_t);
static int usb_setfilter_linux(pcap_t *, struct bpf_program *);
static int usb_setdirection_linux(pcap_t *, pcap_direction_t);
static void usb_cleanup_linux_mmap(pcap_t *);
/* facility to add an USB device to the device list*/
static int
usb_dev_add(pcap_if_t** alldevsp, int n, char *err_str)
{
char dev_name[10];
char dev_descr[30];
snprintf(dev_name, 10, USB_IFACE"%d", n);
snprintf(dev_descr, 30, "USB bus number %d", n);
if (pcap_add_if(alldevsp, dev_name, 0,
dev_descr, err_str) < 0)
return -1;
return 0;
}
int
usb_platform_finddevs(pcap_if_t **alldevsp, char *err_str)
{
struct dirent* data;
int ret = 0;
DIR* dir;
/* scan procfs usb bus directory */
dir = opendir(USB_BUS_DIR);
if (!dir) return 0;
while ((ret == 0) && ((data = readdir(dir)) != 0)) {
int n;
char* name = data->d_name;
int len = strlen(name);
/* if this file name does not end with a number it's not of our interest */
if ((len < 1) || !isdigit(name[--len]))
continue;
while (isdigit(name[--len]));
if (sscanf(&name[len+1], "%d", &n) != 1)
continue;
ret = usb_dev_add(alldevsp, n, err_str);
}
closedir(dir);
return ret;
}
static
int usb_mmap(pcap_t* handle)
{
int len = ioctl(handle->fd, MON_IOCQ_RING_SIZE);
if (len < 0)
return 0;
handle->buffer = mmap(0, len, PROT_READ, MAP_SHARED, handle->fd, 0);
return handle->buffer != MAP_FAILED;
}
pcap_t *
usb_create(const char *device, char *ebuf)
{
pcap_t *p;
p = pcap_create_common(device, ebuf);
if (p == NULL)
return (NULL);
p->activate_op = usb_activate;
return (p);
}
static int
usb_activate(pcap_t* handle)
{
char full_path[USB_LINE_LEN];
/* Initialize some components of the pcap structure. */
handle->bufsize = handle->snapshot;
handle->offset = 0;
handle->linktype = DLT_USB_LINUX;
handle->inject_op = usb_inject_linux;
handle->setfilter_op = usb_setfilter_linux;
handle->setdirection_op = usb_setdirection_linux;
handle->set_datalink_op = NULL; /* can't change data link type */
handle->getnonblock_op = pcap_getnonblock_fd;
handle->setnonblock_op = pcap_setnonblock_fd;
/*get usb bus index from device name */
if (sscanf(handle->opt.source, USB_IFACE"%d", &handle->md.ifindex) != 1)
{
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't get USB bus index from %s", handle->opt.source);
return PCAP_ERROR;
}
/*now select the read method: try to open binary interface */
snprintf(full_path, USB_LINE_LEN, LINUX_USB_MON_DEV"%d", handle->md.ifindex);
handle->fd = open(full_path, O_RDONLY, 0);
if (handle->fd >= 0)
{
if (handle->opt.rfmon) {
/*
* Monitor mode doesn't apply to USB devices.
*/
return PCAP_ERROR_RFMON_NOTSUP;
}
/* binary api is available, try to use fast mmap access */
if (usb_mmap(handle)) {
handle->stats_op = usb_stats_linux_bin;
handle->read_op = usb_read_linux_mmap;
handle->cleanup_op = usb_cleanup_linux_mmap;
/*
* "handle->fd" is a real file, so "select()" and
* "poll()" work on it.
*/
handle->selectable_fd = handle->fd;
return 0;
}
/* can't mmap, use plain binary interface access */
handle->stats_op = usb_stats_linux_bin;
handle->read_op = usb_read_linux_bin;
}
else {
/*Binary interface not available, try open text interface */
snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR"/%dt", handle->md.ifindex);
handle->fd = open(full_path, O_RDONLY, 0);
if (handle->fd < 0)
{
/* no more fallback, give it up*/
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't open USB bus file %s: %s", full_path, strerror(errno));
return PCAP_ERROR;
}
handle->stats_op = usb_stats_linux;
handle->read_op = usb_read_linux;
}
if (handle->opt.rfmon) {
/*
* Monitor mode doesn't apply to USB devices.
*/
return PCAP_ERROR_RFMON_NOTSUP;
}
/*
* "handle->fd" is a real file, so "select()" and "poll()"
* work on it.
*/
handle->selectable_fd = handle->fd;
/* for plain binary access and text access we need to allocate the read
* buffer */
handle->buffer = malloc(handle->bufsize);
if (!handle->buffer) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"malloc: %s", pcap_strerror(errno));
return PCAP_ERROR;
}
return 0;
}
static inline int
ascii_to_int(char c)
{
return c < 'A' ? c- '0': ((c<'a') ? c - 'A' + 10: c-'a'+10);
}
/*
* see <linux-kernel-source>/Documentation/usb/usbmon.txt and
* <linux-kernel-source>/drivers/usb/mon/mon_text.c for urb string
* format description
*/
static int
usb_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
{
/* see:
* /usr/src/linux/Documentation/usb/usbmon.txt
* for message format
*/
unsigned timestamp;
int tag, cnt, ep_num, dev_addr, dummy, ret, urb_len, data_len;
char etype, pipeid1, pipeid2, status[16], urb_tag, line[USB_LINE_LEN];
char *string = line;
u_char * rawdata = handle->buffer;
struct pcap_pkthdr pkth;
pcap_usb_header* uhdr = (pcap_usb_header*)handle->buffer;
u_char urb_transfer=0;
int incoming=0;
/* ignore interrupt system call errors */
do {
ret = read(handle->fd, line, USB_LINE_LEN - 1);
if (handle->break_loop)
{
handle->break_loop = 0;
return -2;
}
} while ((ret == -1) && (errno == EINTR));
if (ret < 0)
{
if (errno == EAGAIN)
return 0; /* no data there */
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't read from fd %d: %s", handle->fd, strerror(errno));
return -1;
}
/* read urb header; %n argument may increment return value, but it's
* not mandatory, so does not count on it*/
string[ret] = 0;
ret = sscanf(string, "%x %d %c %c%c:%d:%d %s%n", &tag, &timestamp, &etype,
&pipeid1, &pipeid2, &dev_addr, &ep_num, status,
&cnt);
if (ret < 8)
{
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't parse USB bus message '%s', too few tokens (expected 8 got %d)",
string, ret);
return -1;
}
uhdr->id = tag;
uhdr->endpoint_number = ep_num;
uhdr->device_address = dev_addr;
uhdr->bus_id = handle->md.ifindex;
uhdr->status = 0;
string += cnt;
/* don't use usbmon provided timestamp, since it have low precision*/
if (gettimeofday(&pkth.ts, NULL) < 0)
{
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't get timestamp for message '%s' %d:%s",
string, errno, strerror(errno));
return -1;
}
uhdr->ts_sec = pkth.ts.tv_sec;
uhdr->ts_usec = pkth.ts.tv_usec;
/* parse endpoint information */
if (pipeid1 == 'C')
urb_transfer = URB_CONTROL;
else if (pipeid1 == 'Z')
urb_transfer = URB_ISOCHRONOUS;
else if (pipeid1 == 'I')
urb_transfer = URB_INTERRUPT;
else if (pipeid1 == 'B')
urb_transfer = URB_BULK;
if (pipeid2 == 'i') {
urb_transfer |= URB_TRANSFER_IN;
incoming = 1;
}
if (etype == 'C')
incoming = !incoming;
/* direction check*/
if (incoming)
{
if (handle->direction == PCAP_D_OUT)
return 0;
}
else
if (handle->direction == PCAP_D_IN)
return 0;
uhdr->event_type = etype;
uhdr->transfer_type = urb_transfer;
pkth.caplen = sizeof(pcap_usb_header);
rawdata += sizeof(pcap_usb_header);
/* check if this is a setup packet */
ret = sscanf(status, "%d", &dummy);
if (ret != 1)
{
/* this a setup packet, setup data can be filled with underscore if
* usbmon has not been able to read them, so we must parse this fields as
* strings */
pcap_usb_setup* shdr;
char str1[3], str2[3], str3[5], str4[5], str5[5];
ret = sscanf(string, "%s %s %s %s %s%n", str1, str2, str3, str4,
str5, &cnt);
if (ret < 5)
{
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't parse USB bus message '%s', too few tokens (expected 5 got %d)",
string, ret);
return -1;
}
string += cnt;
/* try to convert to corresponding integer */
shdr = &uhdr->setup;
shdr->bmRequestType = strtoul(str1, 0, 16);
shdr->bRequest = strtoul(str2, 0, 16);
shdr->wValue = htols(strtoul(str3, 0, 16));
shdr->wIndex = htols(strtoul(str4, 0, 16));
shdr->wLength = htols(strtoul(str5, 0, 16));
uhdr->setup_flag = 0;
}
else
uhdr->setup_flag = 1;
/* read urb data */
ret = sscanf(string, " %d%n", &urb_len, &cnt);
if (ret < 1)
{
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't parse urb length from '%s'", string);
return -1;
}
string += cnt;
/* urb tag is not present if urb length is 0, so we can stop here
* text parsing */
pkth.len = urb_len+pkth.caplen;
uhdr->urb_len = urb_len;
uhdr->data_flag = 1;
data_len = 0;
if (uhdr->urb_len == pkth.caplen)
goto got;
/* check for data presence; data is present if and only if urb tag is '=' */
if (sscanf(string, " %c", &urb_tag) != 1)
{
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't parse urb tag from '%s'", string);
return -1;
}
if (urb_tag != '=')
goto got;
/* skip urb tag and following space */
string += 3;
/* if we reach this point we got some urb data*/
uhdr->data_flag = 0;
/* read all urb data; if urb length is greater then the usbmon internal
* buffer length used by the kernel to spool the URB, we get only
* a partial information.
* At least until linux 2.6.17 there is no way to set usbmon intenal buffer
* length and default value is 130. */
while ((string[0] != 0) && (string[1] != 0) && (pkth.caplen < handle->snapshot))
{
rawdata[0] = ascii_to_int(string[0]) * 16 + ascii_to_int(string[1]);
rawdata++;
string+=2;
if (string[0] == ' ')
string++;
pkth.caplen++;
data_len++;
}
got:
uhdr->data_len = data_len;
handle->md.packets_read++;
if (pkth.caplen > handle->snapshot)
pkth.caplen = handle->snapshot;
callback(user, &pkth, handle->buffer);
return 1;
}
static int
usb_inject_linux(pcap_t *handle, const void *buf, size_t size)
{
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
"USB devices");
return (-1);
}
static int
usb_stats_linux(pcap_t *handle, struct pcap_stat *stats)
{
int dummy, ret, consumed, cnt;
char string[USB_LINE_LEN];
char token[USB_LINE_LEN];
char * ptr = string;
snprintf(string, USB_LINE_LEN, USB_TEXT_DIR"/%ds", handle->md.ifindex);
int fd = open(string, O_RDONLY, 0);
if (fd < 0)
{
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't open USB stats file %s: %s",
string, strerror(errno));
return -1;
}
/* read stats line */
do {
ret = read(fd, string, USB_LINE_LEN-1);
} while ((ret == -1) && (errno == EINTR));
close(fd);
if (ret < 0)
{
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't read stats from fd %d ", fd);
return -1;
}
string[ret] = 0;
/* extract info on dropped urbs */
for (consumed=0; consumed < ret; ) {
/* from the sscanf man page:
* The C standard says: "Execution of a %n directive does
* not increment the assignment count returned at the completion
* of execution" but the Corrigendum seems to contradict this.
* Do not make any assumptions on the effect of %n conversions
* on the return value and explicitly check for cnt assignmet*/
cnt = -1;
int ntok = sscanf(ptr, "%s%n", token, &cnt);
if ((ntok < 1) || (cnt < 0))
break;
consumed += cnt;
ptr += cnt;
if (strcmp(token, "nreaders") == 0)
ret = sscanf(ptr, "%d", &stats->ps_drop);
else
ret = sscanf(ptr, "%d", &dummy);
if (ntok != 1)
break;
consumed += cnt;
ptr += cnt;
}
stats->ps_recv = handle->md.packets_read;
stats->ps_ifdrop = 0;
return 0;
}
static int
usb_setfilter_linux(pcap_t *p, struct bpf_program *fp)
{
return 0;
}
static int
usb_setdirection_linux(pcap_t *p, pcap_direction_t d)
{
p->direction = d;
return 0;
}
static int
usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats)
{
int ret;
struct mon_bin_stats st;
ret = ioctl(handle->fd, MON_IOCG_STATS, &st);
if (ret < 0)
{
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't read stats from fd %d:%s ", handle->fd, strerror(errno));
return -1;
}
stats->ps_recv = handle->md.packets_read + st.queued;
stats->ps_ifdrop = st.dropped;
return 0;
}
/*
* see <linux-kernel-source>/Documentation/usb/usbmon.txt and
* <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
*/
static int
usb_read_linux_bin(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
{
struct mon_bin_get info;
int ret;
struct pcap_pkthdr pkth;
int clen = handle->snapshot - sizeof(pcap_usb_header);
/* the usb header is going to be part of 'packet' data*/
info.hdr = (pcap_usb_header*) handle->buffer;
info.data = handle->buffer + sizeof(pcap_usb_header);
info.data_len = clen;
/* ignore interrupt system call errors */
do {
ret = ioctl(handle->fd, MON_IOCX_GET, &info);
if (handle->break_loop)
{
handle->break_loop = 0;
return -2;
}
} while ((ret == -1) && (errno == EINTR));
if (ret < 0)
{
if (errno == EAGAIN)
return 0; /* no data there */
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't read from fd %d: %s", handle->fd, strerror(errno));
return -1;
}
/* we can get less that than really captured from kernel, depending on
* snaplen, so adjust header accordingly */
if (info.hdr->data_len < clen)
clen = info.hdr->data_len;
info.hdr->data_len = clen;
pkth.caplen = clen + sizeof(pcap_usb_header);
pkth.len = info.hdr->urb_len + sizeof(pcap_usb_header);
pkth.ts.tv_sec = info.hdr->ts_sec;
pkth.ts.tv_usec = info.hdr->ts_usec;
handle->md.packets_read++;
callback(user, &pkth, handle->buffer);
return 1;
}
/*
* see <linux-kernel-source>/Documentation/usb/usbmon.txt and
* <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
*/
#define VEC_SIZE 32
static int
usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
{
struct mon_bin_mfetch fetch;
int32_t vec[VEC_SIZE];
struct pcap_pkthdr pkth;
pcap_usb_header* hdr;
int nflush = 0;
int packets = 0;
for (;;) {
int i, ret;
int limit = max_packets - packets;
if (limit <= 0)
limit = VEC_SIZE;
if (limit > VEC_SIZE)
limit = VEC_SIZE;
/* try to fetch as many events as possible*/
fetch.offvec = vec;
fetch.nfetch = limit;
fetch.nflush = nflush;
/* ignore interrupt system call errors */
do {
ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch);
if (handle->break_loop)
{
handle->break_loop = 0;
return -2;
}
} while ((ret == -1) && (errno == EINTR));
if (ret < 0)
{
if (errno == EAGAIN)
return 0; /* no data there */
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
"Can't mfetch fd %d: %s", handle->fd, strerror(errno));
return -1;
}
/* keep track of processed events, we will flush them later */
nflush = fetch.nfetch;
for (i=0; i<fetch.nfetch; ++i) {
/* discard filler */
hdr = (pcap_usb_header*) &handle->buffer[vec[i]];
if (hdr->event_type == '@')
continue;
/* get packet info from header*/
pkth.caplen = hdr->data_len + sizeof(pcap_usb_header);
pkth.len = hdr->urb_len + sizeof(pcap_usb_header);
pkth.ts.tv_sec = hdr->ts_sec;
pkth.ts.tv_usec = hdr->ts_usec;
handle->md.packets_read++;
callback(user, &pkth, (u_char*) hdr);
packets++;
}
/* with max_packets <= 0 we stop afer the first chunk*/
if ((max_packets <= 0) || (packets == max_packets))
break;
}
/* flush pending events*/
ioctl(handle->fd, MON_IOCH_MFLUSH, nflush);
return packets;
}
static void
usb_cleanup_linux_mmap(pcap_t* handle)
{
/* buffer must not be freed because it's memory mapped */
/* XXX - does it need to be unmapped? */
handle->buffer = NULL;
pcap_cleanup_live_common(handle);
}
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