Commit 413a4317 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by David S. Miller
Browse files

VSOCK: add sock_diag interface 



This patch adds the sock_diag interface for querying sockets from
userspace.  Tools like ss(8) and netstat(8) can use this interface to
list open sockets.

The userspace ABI is defined in <linux/vm_sockets_diag.h> and includes
netlink request and response structs.  The request can query sockets
based on their sk_state (e.g. listening sockets only) and the response
contains socket information fields including the local/remote addresses,
inode number, etc.

This patch does not dump VMCI pending sockets because I have only tested
the virtio transport, which does not use pending sockets.  Support can
be added later by extending vsock_diag_dump() if needed by VMCI users.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3b4477d2

MAINTAINERS

+2 −0
Original line number Diff line number Diff line
@@ -14286,6 +14286,8 @@ S: Maintained 
F:	include/linux/virtio_vsock.h

F:	include/uapi/linux/virtio_vsock.h

F:	include/uapi/linux/vsockmon.h

F:	include/uapi/linux/vm_sockets_diag.h

F:	net/vmw_vsock/diag.c

F:	net/vmw_vsock/af_vsock_tap.c

F:	net/vmw_vsock/virtio_transport_common.c

F:	net/vmw_vsock/virtio_transport.c

include/uapi/linux/vm_sockets_diag.h

0 → 100644
+33 −0
Original line number Diff line number Diff line 
/* AF_VSOCK sock_diag(7) interface for querying open sockets */



#ifndef _UAPI__VM_SOCKETS_DIAG_H__

#define _UAPI__VM_SOCKETS_DIAG_H__



#include <linux/types.h>



/* Request */

struct vsock_diag_req {

	__u8	sdiag_family;	/* must be AF_VSOCK */

	__u8	sdiag_protocol;	/* must be 0 */

	__u16	pad;		/* must be 0 */

	__u32	vdiag_states;	/* query bitmap (e.g. 1 << TCP_LISTEN) */

	__u32	vdiag_ino;	/* must be 0 (reserved) */

	__u32	vdiag_show;	/* must be 0 (reserved) */

	__u32	vdiag_cookie[2];

};



/* Response */

struct vsock_diag_msg {

	__u8	vdiag_family;	/* AF_VSOCK */

	__u8	vdiag_type;	/* SOCK_STREAM or SOCK_DGRAM */

	__u8	vdiag_state;	/* sk_state (e.g. TCP_LISTEN) */

	__u8	vdiag_shutdown; /* local RCV_SHUTDOWN | SEND_SHUTDOWN */

	__u32   vdiag_src_cid;

	__u32   vdiag_src_port;

	__u32   vdiag_dst_cid;

	__u32   vdiag_dst_port;

	__u32	vdiag_ino;

	__u32	vdiag_cookie[2];

};



#endif /* _UAPI__VM_SOCKETS_DIAG_H__ */

net/vmw_vsock/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -15,6 +15,16 @@ config VSOCKETS 
	  To compile this driver as a module, choose M here: the module

	  will be called vsock. If unsure, say N.



config VSOCKETS_DIAG

	tristate "Virtual Sockets monitoring interface"

	depends on VSOCKETS

	default y

	help

	  Support for PF_VSOCK sockets monitoring interface used by the ss tool.

	  If unsure, say Y.



	  Enable this module so userspace applications can query open sockets.



config VMWARE_VMCI_VSOCKETS

	tristate "VMware VMCI transport for Virtual Sockets"

	depends on VSOCKETS && VMWARE_VMCI

net/vmw_vsock/Makefile

+3 −0
Original line number Diff line number Diff line 
obj-$(CONFIG_VSOCKETS) += vsock.o

obj-$(CONFIG_VSOCKETS_DIAG) += vsock_diag.o

obj-$(CONFIG_VMWARE_VMCI_VSOCKETS) += vmw_vsock_vmci_transport.o

obj-$(CONFIG_VIRTIO_VSOCKETS) += vmw_vsock_virtio_transport.o

obj-$(CONFIG_VIRTIO_VSOCKETS_COMMON) += vmw_vsock_virtio_transport_common.o
@@ -6,6 +7,8 @@ obj-$(CONFIG_HYPERV_VSOCKETS) += hv_sock.o 


vsock-y += af_vsock.o af_vsock_tap.o vsock_addr.o



vsock_diag-y += diag.o



vmw_vsock_vmci_transport-y += vmci_transport.o vmci_transport_notify.o \

	vmci_transport_notify_qstate.o

net/vmw_vsock/diag.c

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+186 −0
Original line number Diff line number Diff line 
/*

 * vsock sock_diag(7) module

 *

 * Copyright (C) 2017 Red Hat, Inc.

 * Author: Stefan Hajnoczi <stefanha@redhat.com>

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the Free

 * Software Foundation version 2 and no later version.

 *

 * This program is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 */



#include <linux/module.h>

#include <linux/sock_diag.h>

#include <linux/vm_sockets_diag.h>

#include <net/af_vsock.h>



static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,

			u32 portid, u32 seq, u32 flags)

{

	struct vsock_sock *vsk = vsock_sk(sk);

	struct vsock_diag_msg *rep;

	struct nlmsghdr *nlh;



	nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),

			flags);

	if (!nlh)

		return -EMSGSIZE;



	rep = nlmsg_data(nlh);

	rep->vdiag_family = AF_VSOCK;



	/* Lock order dictates that sk_lock is acquired before

	 * vsock_table_lock, so we cannot lock here.  Simply don't take

	 * sk_lock; sk is guaranteed to stay alive since vsock_table_lock is

	 * held.

	 */

	rep->vdiag_type = sk->sk_type;

	rep->vdiag_state = sk->sk_state;

	rep->vdiag_shutdown = sk->sk_shutdown;

	rep->vdiag_src_cid = vsk->local_addr.svm_cid;

	rep->vdiag_src_port = vsk->local_addr.svm_port;

	rep->vdiag_dst_cid = vsk->remote_addr.svm_cid;

	rep->vdiag_dst_port = vsk->remote_addr.svm_port;

	rep->vdiag_ino = sock_i_ino(sk);



	sock_diag_save_cookie(sk, rep->vdiag_cookie);



	return 0;

}



static int vsock_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)

{

	struct vsock_diag_req *req;

	struct vsock_sock *vsk;

	unsigned int bucket;

	unsigned int last_i;

	unsigned int table;

	struct net *net;

	unsigned int i;



	req = nlmsg_data(cb->nlh);

	net = sock_net(skb->sk);



	/* State saved between calls: */

	table = cb->args[0];

	bucket = cb->args[1];

	i = last_i = cb->args[2];



	/* TODO VMCI pending sockets? */



	spin_lock_bh(&vsock_table_lock);



	/* Bind table (locally created sockets) */

	if (table == 0) {

		while (bucket < ARRAY_SIZE(vsock_bind_table)) {

			struct list_head *head = &vsock_bind_table[bucket];



			i = 0;

			list_for_each_entry(vsk, head, bound_table) {

				struct sock *sk = sk_vsock(vsk);



				if (!net_eq(sock_net(sk), net))

					continue;

				if (i < last_i)

					goto next_bind;

				if (!(req->vdiag_states & (1 << sk->sk_state)))

					goto next_bind;

				if (sk_diag_fill(sk, skb,

						 NETLINK_CB(cb->skb).portid,

						 cb->nlh->nlmsg_seq,

						 NLM_F_MULTI) < 0)

					goto done;

next_bind:

				i++;

			}

			last_i = 0;

			bucket++;

		}



		table++;

		bucket = 0;

	}



	/* Connected table (accepted connections) */

	while (bucket < ARRAY_SIZE(vsock_connected_table)) {

		struct list_head *head = &vsock_connected_table[bucket];



		i = 0;

		list_for_each_entry(vsk, head, connected_table) {

			struct sock *sk = sk_vsock(vsk);



			/* Skip sockets we've already seen above */

			if (__vsock_in_bound_table(vsk))

				continue;



			if (!net_eq(sock_net(sk), net))

				continue;

			if (i < last_i)

				goto next_connected;

			if (!(req->vdiag_states & (1 << sk->sk_state)))

				goto next_connected;

			if (sk_diag_fill(sk, skb,

					 NETLINK_CB(cb->skb).portid,

					 cb->nlh->nlmsg_seq,

					 NLM_F_MULTI) < 0)

				goto done;

next_connected:

			i++;

		}

		last_i = 0;

		bucket++;

	}



done:

	spin_unlock_bh(&vsock_table_lock);



	cb->args[0] = table;

	cb->args[1] = bucket;

	cb->args[2] = i;



	return skb->len;

}



static int vsock_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)

{

	int hdrlen = sizeof(struct vsock_diag_req);

	struct net *net = sock_net(skb->sk);



	if (nlmsg_len(h) < hdrlen)

		return -EINVAL;



	if (h->nlmsg_flags & NLM_F_DUMP) {

		struct netlink_dump_control c = {

			.dump = vsock_diag_dump,

		};

		return netlink_dump_start(net->diag_nlsk, skb, h, &c);

	}



	return -EOPNOTSUPP;

}



static const struct sock_diag_handler vsock_diag_handler = {

	.family = AF_VSOCK,

	.dump = vsock_diag_handler_dump,

};



static int __init vsock_diag_init(void)

{

	return sock_diag_register(&vsock_diag_handler);

}



static void __exit vsock_diag_exit(void)

{

	sock_diag_unregister(&vsock_diag_handler);

}



module_init(vsock_diag_init);

module_exit(vsock_diag_exit);

MODULE_LICENSE("GPL");

MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG,

			       40 /* AF_VSOCK */);

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