Re: [PATCH] usb: add pcap support.

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 1/19/21 8:44 PM, Gerd Hoffmann wrote:
> Log all traffic of a specific usb device to a pcap file for later
> inspection.  File format is compatible with linux usb monitor.
> 
> Usage:
>   qemu -device usb-${somedevice},pcap=file.pcap
>   wireshark file.pcap

Great!

> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  include/hw/usb.h   |   8 ++
>  hw/usb/bus.c       |  16 +++
>  hw/usb/core.c      |  17 ++++
>  hw/usb/pcap.c      | 242 +++++++++++++++++++++++++++++++++++++++++++++
>  hw/usb/meson.build |   1 +
>  5 files changed, 284 insertions(+)
>  create mode 100644 hw/usb/pcap.c
...

> diff --git a/hw/usb/pcap.c b/hw/usb/pcap.c
> new file mode 100644
> index 000000000000..d3162d65e5fe
> --- /dev/null
> +++ b/hw/usb/pcap.c
> @@ -0,0 +1,242 @@

Missing license.

> +#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 */
> +};

QEMU_PACKED?

> +
> +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 */
> +};

QEMU_PACKED?

> +
> +/* 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 */

QEMU_PACKED?

Otherwise:
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>