passt/iov.h, branch 2026_05_26.038c51e

iov: Introduce IOV_PUSH_HEADER() macro

2026-05-26T10:17:01+00:00

Add iov_push_header_() and its typed wrapper IOV_PUSH_HEADER() to write
a header into an iov_tail at the current offset and advance past it.

This is the write counterpart to IOV_PEEK_HEADER() / IOV_REMOVE_HEADER(),
using iov_from_buf() to copy the header data across iovec boundaries.

Signed-off-by: Laurent Vivier 
Reviewed-by: David Gibson 
Signed-off-by: Stefano Brivio

iov: Add iov_memcpy() to copy data between iovec arrays

2026-05-19T23:21:09+00:00

Add a helper to copy data from a source iovec array to a destination
iovec array, each starting at an arbitrary byte offset, iterating
through both arrays simultaneously and copying in chunks matching the
smaller of the two current segments.

Signed-off-by: Laurent Vivier 
Reviewed-by: David Gibson 
Reviewed-by: Jon Maloy 
Signed-off-by: Stefano Brivio

iov: Introduce iov_memset()

2026-05-19T23:21:03+00:00

Add a helper to set a range of bytes across an IO vector to a given
value, similar to memset() but operating over scatter-gather buffers.
It skips to the given offset and fills across iovec entries up to the
requested length.

Signed-off-by: Laurent Vivier 
Reviewed-by: David Gibson 
Reviewed-by: Jon Maloy 
Signed-off-by: Stefano Brivio

iov: Add iov_truncate() helper and use it in vu handlers

2026-03-10T14:26:43+00:00

Add a generic iov_truncate() function that truncates an IO vector to a
given number of bytes, returning the number of iov entries that contain
data after truncation.

Use it in udp_vu_sock_recv() and tcp_vu_sock_recv() to replace the
open-coded truncation logic that adjusted iov entries after recvmsg().
Also convert the direct iov_len assignment in tcp_vu_send_flag() to use
iov_truncate() for consistency.

Add an ASSERT() in tcp_vu_data_from_sock() to quiet the Coverity error:

passt/tcp_vu.c:457:3:
  19. overflow_const: Expression "dlen + hdrlen", where "dlen" is known to
      be equal to -86,  and "hdrlen" is known to be equal to 86, underflows
      the type of "dlen + hdrlen", which is type "unsigned long".

Signed-off-by: Laurent Vivier 
Reviewed-by: David Gibson 
Signed-off-by: Stefano Brivio

Add missing includes to headers

2026-03-04T16:39:57+00:00

Support build systems like bazel that check that headers are
self-contained.

Also update includes so that clang-include-cleaner succeeds.

Tested with:
clang-include-cleaner-19 --extra-arg=-D_GNU_SOURCE --extra-arg=-DPAGE_SIZE=4096 --extra-arg=-DVERSION=\"git\" --extra-arg=-DHAS_GETRANDOM *.h *.c

Signed-off-by: Peter Foley 
Signed-off-by: Stefano Brivio

treewide: Fix places where we incorrectly indented with spaces

2026-01-11T00:31:50+00:00

Had a moment to address this trivial issue.

The passt convention is to indent code with tabs (K&R / kernel style).
However there were a handful of places where we used spaces instead.  Fix
them.

Link: https://bugs.passt.top/show_bug.cgi?id=135
Reported-by: Xun Gu 
Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

tap: Use iov_tail with tap_add_packet()

2025-09-03T18:42:20+00:00

Use IOV_PEEK_HEADER() to get the ethernet header from the iovec.

Move the workaround about multiple iovec array from vu_handle_tx() to
tap_add_packet(). Removing the offset out of the iovec array should
reduce the iovec count to 1.

Signed-off-by: Laurent Vivier 
Reviewed-by: David Gibson 
Signed-off-by: Stefano Brivio

iov: Update IOV_REMOVE_HEADER() and IOV_PEEK_HEADER()

2025-09-03T18:42:17+00:00

Provide a temporary variable of the wanted type to store
the header if the memory in the iovec array is not contiguous.

Signed-off-by: Laurent Vivier 
Reviewed-by: David Gibson 
Signed-off-by: Stefano Brivio

iov: Introduce iov_tail_clone() and iov_drop_header().

2025-09-03T18:42:15+00:00

These utilities enhance iov_tail manipulation, useful for
efficient packet processing by enabling iovec array cloning and
header stripping without data copies.

- iov_drop_header(): Discards a specified number of bytes from the
  beginning of an iov_tail by advancing its internal offset and pruning
  consumed elements.

- iov_tail_clone(): Clone an iov_tail into an iovec array, adjusting the
first iovec entry to remove the iov_tail offset.

Signed-off-by: Laurent Vivier 
Reviewed-by: David Gibson 
Signed-off-by: Stefano Brivio

style: Fix 'Return' comment style

2025-07-18T17:19:24+00:00

We always use imperative (no 'Returns:'), no tab after the ':' and
only one space, the first character is always lowercase.

This is fixed with:

 sed -i "s/Returns:/Return:/;s/Return:    /Return: /;s/Return:  */Return: /;s/Return: \([A-Z]\)/Return: \L\1/" *.[ch]

And manually updated to fix alignment of multiline comment and words
that must keep uppercase (like IPv4, TCP, UDP, Layer-4).

Signed-off-by: Laurent Vivier 
Signed-off-by: Stefano Brivio