tftpd not working when net.inet.udp.blackhole=1

[Nikolay Pavlov]

Hi folks.
I have a strange problem with tftpd when using sysctl
net.inet.udp.blackhole=1 It's not working with this variable enabled.

I use tftp to upload images from my routers. Here is details of the
problem:

OS FreeBSD 6.0-RELEASE-p6

root at ipstat:~/projects/route_tools# sysctl net.inet.udp.blackhole=1
net.inet.udp.blackhole: 0 -> 1

telnet at fbi8000-Border-NY#copy running-conf tftp XX.XX.48.25
XX.XX.51.194.runcfg.new
TFTP session timed out
Error - can't upload running-config to TFTP server.

root at ipstat:~/projects/route_tools# tail -f /var/log/xferlog
Jul  3 11:25:01 ipstat tftpd[31151]: XX.XX.82.18: write request for
//XX.XX.51.194.runcfg.new: success
Jul  3 11:25:05 ipstat tftpd[31157]: XX.XX.82.18: write request for
//XX.XX.51.194.runcfg.new: success
Jul  3 11:25:10 ipstat tftpd[31161]: XX.XX.82.18: write request for
//XX.XX.51.194.runcfg.new: success
Jul  3 11:25:14 ipstat tftpd[31165]: XX.XX.82.18: write request for
//XX.XX.51.194.runcfg.new: success

But it was not uploded.

root at ipstat:~/projects/route_tools# tcpdump -nvvi rl0 port 69
tcpdump: listening on rl0, link-type EN10MB (Ethernet), capture size 96
bytes
11:23:46.663758 IP (tos 0x0, ttl  56, id 24435, offset 0, flags [DF],
proto: UDP (17), length: 62) XX.XX.82.18.1027 > XX.XX.48.25.69: [udp
sum ok]  34 WRQ "XX.XX.51.194.runcfg.new" octet
11:23:50.817992 IP (tos 0x0, ttl  56, id 24610, offset 0, flags [DF],
proto: UDP (17), length: 62) XX.XX.82.18.1027 > XX.XX.48.25.69: [udp
sum ok]  34 WRQ "XX.XX.51.194.runcfg.new" octet
11:23:55.042069 IP (tos 0x0, ttl  56, id 24817, offset 0, flags [DF],
proto: UDP (17), length: 62) XX.XX.82.18.1027 > XX.XX.48.25.69: [udp
sum ok]  34 WRQ "XX.XX.51.194.runcfg.new" octet
11:23:59.265966 IP (tos 0x0, ttl  56, id 25120, offset 0, flags [DF],
proto: UDP (17), length: 62) XX.XX.82.18.1027 > XX.XX.48.25.69: [udp
sum ok]  34 WRQ "XX.XX.51.194.runcfg.new" octet

Now we disable blackhole:

root at ipstat:~/projects/route_tools# sysctl net.inet.udp.blackhole=0
net.inet.udp.blackhole: 1 -> 0

telnet at fbi8000-Border-NY#copy running-conf tftp XX.XX.48.25
XX.XX.51.194.runcfg.new
Upload running-config to TFTP server done.

root at ipstat:~/projects/route_tools# tail -f /var/log/xferlog
Jul  3 11:32:56 ipstat tftpd[31585]: XX.XX.82.18: write request for
//XX.XX.51.194.runcfg.new: success

root at ipstat:~/projects/route_tools# tcpdump -nvvi rl0 port 69
tcpdump: listening on rl0, link-type EN10MB (Ethernet), capture size 96
bytes
11:32:55.609803 IP (tos 0x0, ttl  56, id 51742, offset 0, flags [DF],
proto: UDP (17), length: 62) XX.XX.82.18.1027 > XX.XX.48.25.69: [udp
sum ok]  34 WRQ "XX.XX.51.194.runcfg.new" octet


What is the secret of such behaviour? Should i submit a PR?



-- 
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= Best regards, Nikolay Pavlov. <<<------------------------------------ = 
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