Hi Stephen,
Thank you for immediate response. When PACKET_FANOUT_FLAG_DEFRAG flag is removed in AF_PACKET mode, IP fragment packets cannot be reassembled. That is what we expected or OVS expected. The file drivers/net/af_packet/rte_net_af_packet.c +770 #if defined(PACKET_FANOUT) fanout_arg = (getpid() ^ (*internals)->if_index) & 0xffff; fanout_arg |= (PACKET_FANOUT_HASH | PACKET_FANOUT_FLAG_DEFRAG) << 16; ==> fanout_arg |= (PACKET_FANOUT_HASH) << 16; #if defined(PACKET_FANOUT_FLAG_ROLLOVER) fanout_arg |= PACKET_FANOUT_FLAG_ROLLOVER << 16; #endif #endif Best regards, Matthew At 2024-01-09 00:42:32, "Stephen Hemminger" <step...@networkplumber.org> wrote: >On Mon, 8 Jan 2024 19:07:20 +0800 (CST) >钟 <gdsgsx2...@163.com> wrote: > >> Hi All, >> >> >> Recently I debug ovs-dpdk with AF_PACKET mode. When IP fragment packets are >> received via DPDK, the IP fragment packets are reassembled by DPDK. After >> reassembly, the packet length is over 1518. They are discarded by OVS >> because of oversize packets. >> >> >> I don't understandy why PACKET_FLAG_DEFRAG is set for AF_PACKET mode. >> >> > >Not sure, but it looks like the af_packet wants to hash packets for fanout. >Hashin of fragments won't work correctly, and packet will arrive on different >queues if fragmented.
