CODEWITHSUNDEEP
clinuxudprecvmsg
Kokomelom
Kokomelom

Reputation: 353

How to make recvmsg failed in Linux system

Is there any way how to makes to recvmsg that listen to UDP to return value that smaller than 0?

I can't run code on the system, only send UDP packet.

Edit:

I have tried the @Ben Voigt offer , sending to this port ICMP Port Unreachable packet to this port and that may trigger ECONNRESET or ECONNREFUSED So I tried this code

from scapy.all import *
send(IP(dst=dst_ip)/UDP(sport=src_port,dport=dst_port))
[here is PCAP file][1] , when I run that code the `recvmsg` has been called(not return -1 of-course)

So no I tried to send ICMP Port Unreachable to that port and hope that recvmsg will fail

from scapy.all import *
send(IP(dst=dst_ip)/ICMP(type=3,code=3)/IP(dst=dst_ip)/UDP(sport=src_port,dport=dst_port))

enter image description here

here is PCAP file but the recvmsg not even called

Upvotes: 0

Views: 429

Answers (1)

Maxim Egorushkin
Maxim Egorushkin

Reputation: 136485

If you want recvmsg return -1 for testing, implement your own recvmsg in a shared library and inject it in your program with LD_PRELOAD. See The LD_PRELOAD trick for more details.

Upvotes: 2

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