#978062 sendip: corrupted ipv4 header

Package:
sendip
Source:
sendip
Description:
Commandline tool to allow sending arbitrary IP packets
Submitter:
Evgeniy Berdnikov
Date:
2020-12-25 09:36:03 UTC
Severity:
normal
#978062#5
Date:
2020-12-25 09:28:00 UTC
From:
To:
Dear Maintainer,

trying to send TCP SYN packet to 87.250.250.242:443 with

# sendip -v -p ipv4 -is 172.31.39.82 -id 87.250.250.242 -p tcp -ts 1234 -id 443 -tfs  1 87.250.250.242
Added 47 options
Initializing module ipv4
Initializing module tcp
Finalizing module tcp
Finalizing module ipv4
Final packet data:
45 00 00 28   E..(
1E F7 00 00   ....
FF 06 C7 AC   ....
AC 1F 27 52   ..'R
00 00 01 BB   ....
04 D2 00 00   ....
2A 7E 60 71   *~`q
00 00 00 00   ....
50 02 FF FF   P...
4A F5 00 00   J...
Setting socket options:
 IP_HDRINCL
Sent 40 bytes to 87.250.250.242
Freeing module ipv4
Freeing module tcp

I got via tcpdump:

listening on wlan0, link-type EN10MB (Ethernet), capture size 262144 bytes
11:58:45.520319 IP 172.31.39.82.1234 > 0.0.1.187.0: Flags [S], seq 712925297, win 65535, length 0

So, ipv4 destination address is broken, and line "00 00 01 BB" from
sendip output confirms that ipv4 header is corrupted.
Destination port is also wrong.