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pcap: Add appropriate endianness conversions for USB pcap header
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The USB pcap header should always be little endian. As such, add the
appropriate conversions where necessary to ensure that the data is
interpreted correctly on big endian architectures.
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@benzea
benzea committed Mar 3, 2024
1 parent 570b58e commit 671e399
Showing 1 changed file with 17 additions and 17 deletions.
34 changes: 17 additions & 17 deletions src/umockdev-pcap.vala
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Original file line number Diff line number Diff line change
Expand Up @@ -207,7 +207,7 @@ internal class IoctlUsbPcapHandler : IoctlBase {
usb_header_mmapped *urb_hdr = (void*) cur_buf;

cur_waiting_since = now;
last_pkt_time_ms = urb_hdr.ts_sec * 1000 + urb_hdr.ts_usec / 1000;
last_pkt_time_ms = from_little_endian(urb_hdr.ts_sec) * 1000 + from_little_endian(urb_hdr).ts_usec / 1000;
start_time_ms = last_pkt_time_ms;
}

Expand All @@ -216,10 +216,10 @@ internal class IoctlUsbPcapHandler : IoctlBase {

usb_header_mmapped *urb_hdr = (void*) cur_buf;

uint64 cur_pkt_time_ms = urb_hdr.ts_sec * 1000 + urb_hdr.ts_usec / 1000;
uint64 cur_pkt_time_ms = from_little_endian(urb_hdr.ts_sec) * 1000 + from_little_endian(urb_hdr).ts_usec / 1000;

/* Discard anything from a different bus/device */
if (urb_hdr.bus_id != bus || urb_hdr.device_address != device)
if (from_little_endian(urb_hdr.bus_id) != bus || urb_hdr.device_address != device)
continue;

/* Print out debug info, if we need 5s longer than the recording
Expand All @@ -230,7 +230,7 @@ internal class IoctlUsbPcapHandler : IoctlBase {
(ulong) (now - cur_waiting_since) / 1000,
(ulong) (cur_pkt_time_ms - last_pkt_time_ms));
message("Trying to reap at recording position %c %s packet, for endpoint 0x%02x with length %u, replay may be stuck (time: %.3f)",
urb_hdr.event_type, urb_type_to_string(urb_hdr.transfer_type), urb_hdr.endpoint_number, urb_hdr.urb_len, (cur_pkt_time_ms - start_time_ms) / 1000.0);
urb_hdr.event_type, urb_type_to_string(urb_hdr.transfer_type), urb_hdr.endpoint_number, from_little_endian(urb_hdr.urb_len), (cur_pkt_time_ms - start_time_ms) / 1000.0);
message("The device has currently %u in-flight URBs:", urbs.length);

for (var i = 0; i < urbs.length; i++) {
Expand Down Expand Up @@ -277,7 +277,7 @@ internal class IoctlUsbPcapHandler : IoctlBase {
*/
if ((urb.type != urb_hdr.transfer_type) ||
((urb.type != URB_CONTROL) && (urb.endpoint != urb_hdr.endpoint_number)) ||
(urb_buffer_length != urb_hdr.urb_len)) {
(urb_buffer_length != from_little_endian(urb_hdr.urb_len))) {

if (debug)
stderr.printf("UMockdev: Queued URB %d has a metadata mismatch!\n", i);
Expand All @@ -290,10 +290,10 @@ internal class IoctlUsbPcapHandler : IoctlBase {
continue;
}

if (urb_hdr.data_len > 0) {
if (from_little_endian(urb_hdr.data_len) > 0) {
/* Data must have been captured. */
assert(urb_hdr.data_flag == 0);
assert(urb_hdr.data_len == urb_buffer_length);
assert(from_little_endian(urb_hdr.data_len) == urb_buffer_length);

/* Compare the full buffer (as we are outgoing) */
if (Posix.memcmp(urb_buffer, &cur_buf[sizeof(usb_header_mmapped)], urb_buffer_length) != 0) {
Expand All @@ -317,10 +317,10 @@ internal class IoctlUsbPcapHandler : IoctlBase {
}

/* Everything matches, mark as submitted */
urb_data.pcap_id = urb_hdr.id;
urb_data.pcap_id = from_little_endian(urb_hdr.id);

/* Packet was handled. */
last_pkt_time_ms = urb_hdr.ts_sec * 1000 + urb_hdr.ts_usec / 1000;
last_pkt_time_ms = from_little_endian(urb_hdr.ts_sec) * 1000 + from_little_endian(urb_hdr).ts_usec / 1000;
break;
}

Expand All @@ -337,7 +337,7 @@ internal class IoctlUsbPcapHandler : IoctlBase {
for (int i = 0; i < urbs.length; i++) {
urb_info = urbs.index(i);

if (urb_info.pcap_id == urb_hdr.id) {
if (urb_info.pcap_id == from_little_endian(urb_hdr.id)) {
urb = (Ioctl.usbdevfs_urb*) urb_info.urb_data.data;
urbs.remove_index(i);
break;
Expand All @@ -355,7 +355,7 @@ internal class IoctlUsbPcapHandler : IoctlBase {
/* We can reap this urb!
* Copy any data back if present.
*/
if (urb_hdr.data_len > 0) {
if (from_little_endian(urb_hdr.data_len) > 0) {
assert(urb_hdr.data_flag == 0);

uint8* urb_buffer = urb.buffer;
Expand All @@ -366,16 +366,16 @@ internal class IoctlUsbPcapHandler : IoctlBase {
if (urb.type == URB_CONTROL)
urb_buffer = &urb.buffer[8];

Posix.memcpy(urb_buffer, &cur_buf[sizeof(usb_header_mmapped)], urb_hdr.data_len);
Posix.memcpy(urb_buffer, &cur_buf[sizeof(usb_header_mmapped)], from_little_endian(urb_hdr.data_len));
}
urb.status = (int) urb_hdr.status;
urb.actual_length = (int) urb_hdr.urb_len;
urb.status = (int) from_little_endian(urb_hdr.status);
urb.actual_length = (int) from_little_endian(urb_hdr.urb_len);

/* Does this need further handling? */
assert(urb_hdr.start_frame == 0);
urb.start_frame = (int) urb_hdr.start_frame;
assert(from_little_endian(urb_hdr.start_frame) == 0);
urb.start_frame = (int) from_little_endian(urb_hdr.start_frame);

last_pkt_time_ms = urb_hdr.ts_sec * 1000 + urb_hdr.ts_usec / 1000;
last_pkt_time_ms = from_little_endian(urb_hdr.ts_sec) * 1000 + from_little_endian(urb_hdr).ts_usec / 1000;

return urb_info;
}
Expand Down

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