sendmmsg does not have argument?

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
linux

Research direction

Start by reproducing the sysdig command and comparing DNS traffic from host or nslookup with curl, focusing on the sendmmsg system call identified through strace. Trace how sysdig captures sendmmsg arguments; the work is done when the DNS request arguments are captured consistently alongside the response.

Written by the indexing model from the issue text.

Description

falcosecurity-contrib feature-request

I was tring to monitor DNS request / response in Linux systems, below is the command I used:

$ sysdig -X -s 2000 -p "*%proc.name %evt.dir %evt.type %proc.pid  %fd.cip:%fd.cport  %fd.sip:%fd.sport %fd.l4proto\n%evt.args\n" "fd.sport = 53 and evt.rawres > 0"

Everything is fine when I send a DNS request using host or nslookup, I can see the request and response is captured by sysdig.

However if I use curl to visit a website, sometimes I cannot capture the DNS request ( response can be captured )

So I use strace to find what happened and I found that curl use the system call sendmmsg to send DNS request and Sysdig cannot capture the argument of sendmmsg

Is there any advise for me to solve this problem?

Dominant language
C++
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