Date: Wed, 10 Dec 2025 13:44:25 +0000 From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 291420] [epair] Bad UDP packet checksum with epair(4) and txcsum enabled Message-ID: <bug-291420-7501-s3VZWIWvba@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-291420-7501@https.bugs.freebsd.org/bugzilla/> References: <bug-291420-7501@https.bugs.freebsd.org/bugzilla/>
index | next in thread | previous in thread | raw e-mail
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=291420 --- Comment #19 from Michael Tuexen <tuexen@freebsd.org> --- (In reply to vova from comment #17) The kernel will take care. The problem here is that bge interfaces announce TXCSUM support, but only do this for TCP. All other interfaces I know of, support no checksum offloading at all, TCP and UDP, or SCTP, TCP and UDP. Only TCP is what breaks here UDP traffic. Setting forced_udpcsum to 1, adds support for UDP checksum offloading. Unfortunately, the hardware implementation does not handle the case where the computation gives 0 correctly. That is why the default is off. Disabling TXCSUM also avoids being hit by the problem, since then no checksum offloading at all is done. The long term solution will most likely be to add the capability to the bridge interface to compute the checksum in software when needed. The short term solution might be just to disable TXCSUM per default for epair... -- You are receiving this mail because: You are on the CC list for the bug.help
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-291420-7501-s3VZWIWvba>