site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com Hi, I have a driver which does TCP and UDP checksum offload. The device tells me the partial (payload) checksum, which I fill into m_pkthdr.csum_data. However, udp_input() ignores partial checksums: /* * Checksum extended UDP header and data. */ if (uh->uh_sum) { if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) { if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR) uh->uh_sum = m->m_pkthdr.csum_data; else goto doudpcksum; uh->uh_sum ^= 0xffff; FreeBSD's udp_input() is mostly identical, except in place of goto doudpcksum; it has the code to integrate the partial checksum: uh->uh_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr, htonl((u_short)len + m->m_pkthdr.csum_data + IPPROTO_UDP)); Is this just a bug, or is it a workaround for a broken device? If the latter, is there any way the workaround could be changed to allow for non-broken drivers to pass partial checksums up the stack? Right now, since I want to handle UDP checksum offload, I have some ugly code in my driver figure out if its a tcp or udp packet, and to call in_pseudo() on it (as above) to get the complete checksum. Its pretty ugly, and adds some cost to the receive path. It would be nice to be able to remove it. Thanks, Drew _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... This email sent to site_archiver@lists.apple.com