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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: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stefan Hajnoczi 2017-10-05 16:46:53 -04:00 committed by David S. Miller
parent 3b4477d2dc
commit 413a4317ac
5 changed files with 234 additions and 0 deletions
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2
MAINTAINERS
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@ -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

33
include/uapi/linux/vm_sockets_diag.h Normal file
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@ -0,0 +1,33 @@
/* 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__ */

10
net/vmw_vsock/Kconfig
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@ -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

3
net/vmw_vsock/Makefile
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@ -1,4 +1,5 @@
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

186
net/vmw_vsock/diag.c Normal file
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@ -0,0 +1,186 @@
/*
* 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 */);