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![Stefan Hajnoczi](/assets/img/avatar_default.png)
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>
186 lines
4.4 KiB
C
186 lines
4.4 KiB
C
/*
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* vsock sock_diag(7) module
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*
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* Copyright (C) 2017 Red Hat, Inc.
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* Author: Stefan Hajnoczi <stefanha@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation version 2 and no later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/module.h>
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#include <linux/sock_diag.h>
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#include <linux/vm_sockets_diag.h>
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#include <net/af_vsock.h>
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static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
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u32 portid, u32 seq, u32 flags)
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{
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struct vsock_sock *vsk = vsock_sk(sk);
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struct vsock_diag_msg *rep;
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struct nlmsghdr *nlh;
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nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),
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flags);
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if (!nlh)
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return -EMSGSIZE;
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rep = nlmsg_data(nlh);
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rep->vdiag_family = AF_VSOCK;
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/* Lock order dictates that sk_lock is acquired before
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* vsock_table_lock, so we cannot lock here. Simply don't take
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* sk_lock; sk is guaranteed to stay alive since vsock_table_lock is
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* held.
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*/
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rep->vdiag_type = sk->sk_type;
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rep->vdiag_state = sk->sk_state;
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rep->vdiag_shutdown = sk->sk_shutdown;
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rep->vdiag_src_cid = vsk->local_addr.svm_cid;
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rep->vdiag_src_port = vsk->local_addr.svm_port;
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rep->vdiag_dst_cid = vsk->remote_addr.svm_cid;
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rep->vdiag_dst_port = vsk->remote_addr.svm_port;
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rep->vdiag_ino = sock_i_ino(sk);
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sock_diag_save_cookie(sk, rep->vdiag_cookie);
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return 0;
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}
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static int vsock_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
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{
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struct vsock_diag_req *req;
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struct vsock_sock *vsk;
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unsigned int bucket;
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unsigned int last_i;
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unsigned int table;
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struct net *net;
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unsigned int i;
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req = nlmsg_data(cb->nlh);
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net = sock_net(skb->sk);
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/* State saved between calls: */
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table = cb->args[0];
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bucket = cb->args[1];
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i = last_i = cb->args[2];
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/* TODO VMCI pending sockets? */
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spin_lock_bh(&vsock_table_lock);
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/* Bind table (locally created sockets) */
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if (table == 0) {
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while (bucket < ARRAY_SIZE(vsock_bind_table)) {
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struct list_head *head = &vsock_bind_table[bucket];
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i = 0;
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list_for_each_entry(vsk, head, bound_table) {
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struct sock *sk = sk_vsock(vsk);
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if (!net_eq(sock_net(sk), net))
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continue;
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if (i < last_i)
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goto next_bind;
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if (!(req->vdiag_states & (1 << sk->sk_state)))
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goto next_bind;
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if (sk_diag_fill(sk, skb,
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NETLINK_CB(cb->skb).portid,
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cb->nlh->nlmsg_seq,
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NLM_F_MULTI) < 0)
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goto done;
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next_bind:
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i++;
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}
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last_i = 0;
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bucket++;
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}
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table++;
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bucket = 0;
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}
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/* Connected table (accepted connections) */
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while (bucket < ARRAY_SIZE(vsock_connected_table)) {
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struct list_head *head = &vsock_connected_table[bucket];
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i = 0;
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list_for_each_entry(vsk, head, connected_table) {
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struct sock *sk = sk_vsock(vsk);
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/* Skip sockets we've already seen above */
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if (__vsock_in_bound_table(vsk))
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continue;
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if (!net_eq(sock_net(sk), net))
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continue;
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if (i < last_i)
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goto next_connected;
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if (!(req->vdiag_states & (1 << sk->sk_state)))
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goto next_connected;
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if (sk_diag_fill(sk, skb,
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NETLINK_CB(cb->skb).portid,
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cb->nlh->nlmsg_seq,
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NLM_F_MULTI) < 0)
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goto done;
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next_connected:
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i++;
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}
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last_i = 0;
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bucket++;
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}
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done:
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spin_unlock_bh(&vsock_table_lock);
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cb->args[0] = table;
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cb->args[1] = bucket;
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cb->args[2] = i;
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return skb->len;
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}
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static int vsock_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
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{
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int hdrlen = sizeof(struct vsock_diag_req);
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struct net *net = sock_net(skb->sk);
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if (nlmsg_len(h) < hdrlen)
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return -EINVAL;
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if (h->nlmsg_flags & NLM_F_DUMP) {
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struct netlink_dump_control c = {
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.dump = vsock_diag_dump,
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};
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return netlink_dump_start(net->diag_nlsk, skb, h, &c);
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}
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return -EOPNOTSUPP;
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}
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static const struct sock_diag_handler vsock_diag_handler = {
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.family = AF_VSOCK,
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.dump = vsock_diag_handler_dump,
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};
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static int __init vsock_diag_init(void)
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{
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return sock_diag_register(&vsock_diag_handler);
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}
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static void __exit vsock_diag_exit(void)
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{
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sock_diag_unregister(&vsock_diag_handler);
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}
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module_init(vsock_diag_init);
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module_exit(vsock_diag_exit);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG,
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40 /* AF_VSOCK */);
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