Date: Tue, 17 Dec 2024 12:28:35 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 283380] accepts and processes IPv4 packets destined to non-local MAC addresses instead of dropping them Message-ID: <bug-283380-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D283380 Bug ID: 283380 Summary: accepts and processes IPv4 packets destined to non-local MAC addresses instead of dropping them Product: Base System Version: 14.1-RELEASE Hardware: amd64 OS: Any Status: New Severity: Affects Many People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: jgm@osn.de FreeBSD 14.1-RELEASE-p5 running on Proxmox VE 8.2 with Open vSwitch using v= tnet devices the system accepts and forwards IP packets to non-local MAC addresses which= can be seen on a tcpdump eg tcpdump -netttti vtnet2 host 146.185.xx.yy the MAC address on our vtnet interface is bc:24:11:xx:yy:zz fc:0a:81:xx:yy:zz and 48:f8:db:xx:yy:zz are both non-local/unknown MAC addresses 2024-12-17 13:00:49.618676 fc:0a:81:xx:yy:zz > 48:f8:db:xx:yy:zz, ethertype IPv4 (0x0800), length 79: 146.185.xx.yy.443 > 217.76.xx.yy.60299: Flags [P.= ], seq 600:625, ack 636, win 126, length 25 2024-12-17 13:00:49.618687 bc:24:11:xx:yy:zz > 20:50:0f:xx:yy:zz, ethertype IPv4 (0x0800), length 79: 146.185.xx.yy.443 > 217.76.xx.yy.60299: Flags [P.= ], seq 600:625, ack 636, win 126, length 25 2024-12-17 13:00:49.618910 bc:24:11:xx:yy:zz > 20:50:0f:xx:yy:zz, ethertype IPv4 (0x0800), length 79: 146.185.xx.yy.443 > 217.76.xx.yy.60299: Flags [P.= ], seq 600:625, ack 636, win 126, length 25 2024-12-17 13:00:54.619698 fc:0a:81:xx:yy:zz > 48:f8:db:xx:yy:zz, ethertype IPv4 (0x0800), length 79: 146.185.xx.yy.443 > 217.76.xx.yy.60299: Flags [P.= ], seq 650:675, ack 687, win 126, length 25 2024-12-17 13:00:54.619715 bc:24:11:xx:yy:zz > 20:50:0f:xx:yy:zz, ethertype IPv4 (0x0800), length 79: 146.185.xx.yy.443 > 217.76.xx.yy.60299: Flags [P.= ], seq 650:675, ack 687, win 126, length 25 2024-12-17 13:00:54.619762 bc:24:11:xx:yy:zz > 20:50:0f:xx:yy:zz, ethertype IPv4 (0x0800), length 79: 146.185.xx.yy.443 > 217.76.xx.yy.60299: Flags [P.= ], seq 650:675, ack 687, win 126, length 25 The FreeBSD system "sees" a packet which is flooded on the network because = of the unknown destination MAC address. The problem is that this packet is process= ed and forwarded by the kernel. The MAC 20:50:0f:xx:yy:zz is the correct MAC address of the next hop. Which means the kernel does a route table lookup and forwards the packet to the "correct" n= ext hop which causes duplicates on the receiving end. Furthermore it looks like the kernel itself generates a duplicate of this packet and sent it twice. I would expect that those packets are simple dropped by the kernel. --=20 You are receiving this mail because: You are the assignee for the bug.=
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