On 10/28/26 8:14 PM, Aaron Conole wrote:
> Upcoming commits will be implementing the ChaCha20 high-speed
> symmetric hashing algorithm as part of a CSPRNG for use with
> NAT tuple generation. ChaCha20 treats internal stream data
> as little endian bytes, which means the implementation will
> need a way to read and write byte streams of le32 values.
>
> To facilitate this, introduce the ovs_htole32 and ovs_le32toh
> functions. Some proto-POSIX implementations exist on various
> systems and can be found in `endian.h` or `sys/endian.h`, so
> try to detect those and prefer them. On systems where they
> don't exist, the ovs_* functions will have actual byteswap
> implementations.
>
> Assisted-by: LLM (claude, opencode, sonnet, opus, qwen3.8)
> Signed-off-by: Aaron Conole <[email protected]>
> ---
>
> v2->v3:
> * Reworked to detect the endian.h that exists on the system, and
> hook up ovs_le32toh / ovs_htole32 appropriately based on the
> results of that check.
>
> configure.ac | 7 +++++++
> lib/byte-order.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 55 insertions(+)
>
> diff --git a/configure.ac b/configure.ac
> index db233fad45..c2834c1b3d 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -117,6 +117,13 @@ AC_CHECK_HEADERS([mntent.h sys/statvfs.h linux/types.h
> linux/if_ether.h])
> AC_CHECK_HEADERS([linux/net_namespace.h stdatomic.h bits/floatn-common.h])
> AC_CHECK_HEADERS([net/if_mib.h], [], [], [[#include <sys/types.h>
> #include <net/if.h>]])
> +AC_CHECK_HEADERS([endian.h sys/endian.h])
> +AC_CHECK_DECLS([htole32, le32toh], [], [], [[#if HAVE_ENDIAN_H
> +#include <endian.h>
> +#endif
> +#if HAVE_SYS_ENDIAN_H
We have endif + if here ...
> +#include <sys/endian.h>
> +#endif]])
>
> OVS_CHECK_PKIDIR
> OVS_CHECK_RUNDIR
> diff --git a/lib/byte-order.h b/lib/byte-order.h
> index f5a21f3298..107f02d53b 100644
> --- a/lib/byte-order.h
> +++ b/lib/byte-order.h
> @@ -20,6 +20,7 @@
> #include <netinet/in.h>
> #include <arpa/inet.h>
> #include <inttypes.h>
> +#include <string.h>
> #include "openvswitch/types.h"
>
> #ifndef __CHECKER__
> @@ -71,6 +72,53 @@ uint32_byteswap(uint32_t crc) {
> ((crc & 0xff000000) >> 24));
> }
>
> +#if HAVE_ENDIAN_H
> +#include <endian.h>
> +#elif HAVE_SYS_ENDIAN_H
... and the elif here.
So, both headers may be included on the check, but only one in the
actual code. It is unlikely to cause problems on real systems, but
the inconsistency is not great.
Best regards, Ilya Maximets.
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