On Thu, 2016-04-07 at 11:26 -0700, Eric Dumazet wrote:
> On Thu, 2016-04-07 at 23:01 +0530, Vishnu Pratap Singh wrote:
> > Hi,
> >
> >
> > Issue - How to get PID information for the local tcp connection
> >
> >
> >
> > i want to get the creator PID for each socket in user space for local
> > tcp connection, i see in kernel there is support for returing PID with
> > "SO_PEERCRED" ioctl to work across namespaces. it uses struct pid and
> > struct cred to store the peer credentials on struct sock.
> > cred_to_ucred(sk->sk_peer_pid, sk->sk_peer_cred, &peercred); Above
> > function stores the PID information in ucred->pid = pid_vnr(pid); and
> > same is returned via "SO_PEERCRED" ioctl .
> >
> > But for local tcp connection i get pid as 0, is there any way i can
> > get the PID information. Any help or suggestion will be highly
> > helpful.
> >
> >
>
> man 7 socket
>
> SO_PEERCRED
> Return the credentials of the foreign process connected to
> this socket.
> This is possible only for connected AF_UNIX stream
> sockets and AF_UNIX
> stream and datagram socket pairs created using socketpair(2);
> see unix(7).
> The returned credentials are those that were in effect at
> the time of the
> call to connect(2) or socketpair(2). The argument is a
> ucred structure;
> define the GNU_SOURCE feature test macro to obtain the
> definition of that
> structure from <sys/socket.h>. This socket option is read-only.
>
Sorry, I hit "Send" too fast.
This is not implemented for TCP yet.
You'll have to take a look at iproute2 package, since "ss -tp" is able
to find this information, by looking at all /proc/{pid}/fd/* files and
the socket inode number the kernel gives through inet_diag
Not scalable if you have millions of sockets...
