/*
* usb packet capture
*
* Copyright (c) 2021 Gerd Hoffmann <kraxel@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "hw/usb.h"
#define PCAP_MAGIC 0xa1b2c3d4
#define PCAP_MAJOR 2
#define PCAP_MINOR 4
/* https://wiki.wireshark.org/Development/LibpcapFileFormat */
struct pcap_hdr {
uint32_t magic_number; /* magic number */
uint16_t version_major; /* major version number */
uint16_t version_minor; /* minor version number */
int32_t thiszone; /* GMT to local correction */
uint32_t sigfigs; /* accuracy of timestamps */
uint32_t snaplen; /* max length of captured packets, in octets */
uint32_t network; /* data link type */
};
struct pcaprec_hdr {
uint32_t ts_sec; /* timestamp seconds */
uint32_t ts_usec; /* timestamp microseconds */
uint32_t incl_len; /* number of octets of packet saved in file */
uint32_t orig_len; /* actual length of packet */
};
/* https://www.tcpdump.org/linktypes.html */
/* linux: Documentation/usb/usbmon.rst */
/* linux: drivers/usb/mon/mon_bin.c */
#define LINKTYPE_USB_LINUX 189 /* first 48 bytes only */
#define LINKTYPE_USB_LINUX_MMAPPED 220 /* full 64 byte header */
struct usbmon_packet {
uint64_t id; /* 0: URB ID - from submission to callback */
unsigned char type; /* 8: Same as text; extensible. */
unsigned char xfer_type; /* ISO (0), Intr, Control, Bulk (3) */
unsigned char epnum; /* Endpoint number and transfer direction */
unsigned char devnum; /* Device address */
uint16_t busnum; /* 12: Bus number */
char flag_setup; /* 14: Same as text */
char flag_data; /* 15: Same as text; Binary zero is OK. */
int64_t ts_sec; /* 16: gettimeofday */
int32_t ts_usec; /* 24: gettimeofday */
int32_t status; /* 28: */
unsigned int length; /* 32: Length of data (submitted or actual) */
unsigned int len_cap; /* 36: Delivered length */
union { /* 40: */
unsigned char setup[8]; /* Only for Control S-type */
struct iso_rec { /* Only for ISO */
int32_t error_count;
int32_t numdesc;
} iso;
} s;
int32_t interval; /* 48: Only for Interrupt and ISO */
int32_t start_frame; /* 52: For ISO */
uint32_t xfer_flags; /* 56: copy of URB's transfer_flags */
uint32_t ndesc; /* 60: Actual number of ISO descriptors */
}; /* 64 total length */
/* ------------------------------------------------------------------------ */
#define CTRL_LEN 4096
#define DATA_LEN 256
static int usbmon_status(USBPacket *p)
{
switch (p->status) {
case USB_RET_SUCCESS:
return 0;
case USB_RET_NODEV:
return -19; /* -ENODEV */
default:
return -121; /* -EREMOTEIO */
}
}
static unsigned int usbmon_epnum(USBPacket *p)
{
unsigned epnum = 0;
epnum |= p->ep->nr;
epnum |= (p->pid == USB_TOKEN_IN) ? 0x80 : 0;
return epnum;
}
static unsigned char usbmon_xfer_type[] = {
[USB_ENDPOINT_XFER_CONTROL] = 2,
[USB_ENDPOINT_XFER_ISOC] = 0,
[USB_ENDPOINT_XFER_BULK] = 3,
[USB_ENDPOINT_XFER_INT] = 1,
};
static void do_usb_pcap_header(FILE *fp, struct usbmon_packet *packet)
{
struct pcaprec_hdr header;
struct timeval tv;
gettimeofday(&tv, NULL);
packet->ts_sec = tv.tv_sec;
packet->ts_usec = tv.tv_usec;
header.ts_sec = packet->ts_sec;
header.ts_usec = packet->ts_usec;
header.incl_len = packet->len_cap;
header.orig_len = packet->length + sizeof(*packet);
fwrite(&header, sizeof(header), 1, fp);
fwrite(packet, sizeof(*packet), 1, fp);
}
static void do_usb_pcap_ctrl(FILE *fp, USBPacket *p, bool setup)
{
USBDevice *dev = p->ep->dev;
bool in = dev->setup_buf[0] & USB_DIR_IN;
struct usbmon_packet packet = {
.id = 0,
.type = setup ? 'S' : 'C',
.xfer_type = usbmon_xfer_type[USB_ENDPOINT_XFER_CONTROL],
.epnum = in ? 0x80 : 0,
.devnum = dev->addr,
.flag_setup = setup ? 0 : '-',
.flag_data = '=',
.length = dev->setup_len,
};
int data_len = dev->setup_len;
if (data_len > CTRL_LEN) {
data_len = CTRL_LEN;
}
if (setup) {
memcpy(packet.s.setup, dev->setup_buf, 8);
} else {
packet.status = usbmon_status(p);
}
if (in && setup) {
packet.flag_data = '<';
packet.length = 0;
data_len = 0;
}
if (!in && !setup) {
packet.flag_data = '>';
packet.length = 0;
data_len = 0;
}
packet.len_cap = data_len + sizeof(packet);
do_usb_pcap_header(fp, &packet);
if (data_len) {
fwrite(dev->data_buf, data_len, 1, fp);
}
fflush(fp);
}
static void do_usb_pcap_data(FILE *fp, USBPacket *p, bool setup)
{
struct usbmon_packet packet = {
.id = p->id,
.type = setup ? 'S' : 'C',
.xfer_type = usbmon_xfer_type[p->ep->type],
.epnum = usbmon_epnum(p),
.devnum = p->ep->dev->addr,
.flag_setup = '-',
.flag_data = '=',
.length = p->iov.size,
};
int data_len = p->iov.size;
if (p->ep->nr == 0) {
/* ignore control pipe packets */
return;
}
if (data_len > DATA_LEN) {
data_len = DATA_LEN;
}
if (!setup) {
packet.status = usbmon_status(p);
if (packet.length > p->actual_length) {
packet.length = p->actual_length;
}
if (data_len > p->actual_length) {
data_len = p->actual_length;
}
}
if (p->pid == USB_TOKEN_IN && setup) {
packet.flag_data = '<';
packet.length = 0;
data_len = 0;
}
if (p->pid == USB_TOKEN_OUT && !setup) {
packet.flag_data = '>';
packet.length = 0;
data_len = 0;
}
packet.len_cap = data_len + sizeof(packet);
do_usb_pcap_header(fp, &packet);
if (data_len) {
void *buf = g_malloc(data_len);
iov_to_buf(p->iov.iov, p->iov.niov, 0, buf, data_len);
fwrite(buf, data_len, 1, fp);
g_free(buf);
}
fflush(fp);
}
void usb_pcap_init(FILE *fp)
{
struct pcap_hdr header = {
.magic_number = PCAP_MAGIC,
.version_major = 2,
.version_minor = 4,
.snaplen = MAX(CTRL_LEN, DATA_LEN) + sizeof(struct usbmon_packet),
.network = LINKTYPE_USB_LINUX_MMAPPED,
};
fwrite(&header, sizeof(header), 1, fp);
}
void usb_pcap_ctrl(USBPacket *p, bool setup)
{
FILE *fp = p->ep->dev->pcap;
if (!fp) {
return;
}
do_usb_pcap_ctrl(fp, p, setup);
}
void usb_pcap_data(USBPacket *p, bool setup)
{
FILE *fp = p->ep->dev->pcap;
if (!fp) {
return;
}
do_usb_pcap_data(fp, p, setup);
}
