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I have a requirement for similar task as mentioned in this link.. Passive monitoring of sockets in Android. One way is parsing the /proc/net/{tcp,udp,...} tables. But we have to keep on reading continuously for keep on monitoring; which is not efficient way. As it will be a mobile device app, it will eat up the battery as it requires CPU Time for keep on monitoring for time interval (say 1 sec).

But, I am looking for an event based approach. As I googled about the same, I ended with NETLINK for monitoring the sockets. But I observe that Android NDK doesn't have support for the 

#include <linux/sock_diag.h>
#include <linux/inet_diag.h>
#include <linux/unix_diag.h>
#include <linux/packet_diag.h>
#include <linux/netlink_diag.h>

Does anyone tried using NETLINK in Android for monitoring the INET sockets? If so please share the information.

Thanks.

UPDATE: I tried copy pasting the above mentioned files in the "jni" folder and built using ndk-build. Building was successful and also no crashes at the runtime. But, socket creation of type 

socket(AF_NETLINK, SOCK_DGRAM, NETLINK_INET_DIAG)

is failing with error EACCES(13) - Permission to create a socket of the specified type and/or protocol is denied.

Any suggestions how to proceed further?

Suman
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2 Answers2

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In Android Lollipop, Security Enhanced Linux (SELinux) in Android is enabled in "enforce" mode. By observing/looking at the sandbox definitions Android Source Code - SE Policy of the app.te (Below pasted excerpt), there will not be any supports for the netlink sockets.

app.te

# Privileged netlink socket interfaces.
 
neverallow appdomain
 
    self:{
 
        netlink_socket
 
        netlink_firewall_socket
 
        netlink_tcpdiag_socket
 
        netlink_nflog_socket
 
        netlink_xfrm_socket
 
        netlink_audit_socket
 
        netlink_ip6fw_socket
 
        netlink_dnrt_socket
 
    } *;
Community
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Suman
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  • It's no longer the case that apps can't create netlink socket. Source: https://android.googlesource.com/platform/system/sepolicy/+/d31936f89c49bc5c54b84bd5095f3c417da14935%5E%21/#F1 – Mygod Jan 19 '18 at 08:32
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i think, your app should have root permision!

amh
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    While this may help OP, it's better to add more details, explanation, examples, etc. Please [provide answers that don't require clarification from the asker.](https://meta.stackexchange.com/questions/214173/why-do-i-need-50-reputation-to-comment-what-can-i-do-instead) – Til May 27 '19 at 15:29