https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=263229
--- Comment #32 from [email protected] --- A commit in branch stable/15 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=1162a78e0d403c4619dae3fed99ce9a923bc4795 commit 1162a78e0d403c4619dae3fed99ce9a923bc4795 Author: Michael Tuexen <[email protected]> AuthorDate: 2025-09-10 15:13:35 +0000 Commit: Michael Tuexen <[email protected]> CommitDate: 2025-09-14 20:15:57 +0000 dhclient: improve UDP checksum handling When sending UDP packets: * compute the checksum in the correct order. This only has an impact if the length of the payload is odd. * don't send packet with a checksum of zero, use 0xffff instead as required. When receiving UDP packets: * don't do any computations when the checksum is zero. * compute the checksum in the correct order. This only has an impact if the length of the payload is odd. * when computing the checksum, store the pseudo header checksum * if the checksum is computed as zero, use 0xffff instead. * also accept packets, when the checksum in the packet is the pseudo header checksum. The last point fixes a problem when the DHCP client runs in a VM, the DHCP server runs on the host serving the VM and the network interface supports transmit checksum offloading. Since dhclient doesn't use UDP sockets but bpf devices to read the packets, the checksum will be incorrect and only contain the checksum of the pseudo header. PR: 263229 Reviewed by: markj, Timo Völker Tested by: danilo Differential Revision: https://reviews.freebsd.org/D52394 (cherry picked from commit 187ee62c71f2be62870f26ae98de865e330121be) sbin/dhclient/packet.c | 53 +++++++++++++++++++++++++++++++++----------------- 1 file changed, 35 insertions(+), 18 deletions(-) -- You are receiving this mail because: You are the assignee for the bug.
