Hello, All! I think this will be interesting for tcpdump developers.
I'm using: tcpdump version 3.6 libpcap version 0.6 from RedHat 7.2 distribution. While listening ip6 protocol with -v (-vv, or -vvv) option (tcpdump -i eth0 -t ip6 -v) I've found that tcpdump gets into infinite loop after receiving ICMP6 Neighbour Solicitation packet with Source link-layer address option which has length field equal to 0. Tcpdump infinitely prints the slla MAC address. Here are more detailed packets view: ------------------------------------------------------- ETH>>> send_eth: packet to be sent, (from down to up): ETH>>> ETH>>> [ETH form] 00:48:54:13:41:9b > 00:20:2b:00:f5:d5 typ: 0x86dd IP6>>> [IP6 form] IP6>>> Version : 6 IP6>>> Traffic class : 0 IP6>>> Flow label : 0 IP6>>> Payload length : 32 IP6>>> Next header : 58 IP6>>> Hop limit : 255 IP6>>> Source : c0a8:fd00:0000:0000:0000:0000:0000:0039 IP6>>> Destination : c0a8:fd00:0000:0000:0000:0000:0000:0081 IP6>>> No Extention Headers ICMP6>>> [ICMP6 form] ICMP6>>> Type : 135 ICMP6>>> Code : 0 ICMP6>>> Checksum : 0xa676 ICMP6>>> subhdr_ptr : 0x80b53c0 ICMP6>>> Reserved : 0x0 ICMP6>>> Target : c0a8:fd00:0000:0000:0000:0000:0000:0081 ICMP6>>> Options : 0x80b54d0 ICMP6>>> Option #0: ICMP6>>> type: 2 ICMP6>>> len : 0 ICMP6>>> s/t lla: 00:48:54:13:41:9b ETH>>> send_eth: end of packet to be sent. ------------------------------------------- I didn't try tcpdump v3.7, since I had not found any words about this bug in changelog. ...Bye..Dmitry. - This is the TCPDUMP workers list. It is archived at http://www.tcpdump.org/lists/workers/index.html To unsubscribe use mailto:[EMAIL PROTECTED]?body=unsubscribe
