Commit eb4cb008 authored by Craig Gallek's avatar Craig Gallek Committed by David S. Miller

sock_diag: define destruction multicast groups

These groups will contain socket-destruction events for
AF_INET/AF_INET6, IPPROTO_TCP/IPPROTO_UDP.

Near the end of socket destruction, a check for listeners is
performed.  In the presence of a listener, rather than completely
cleanup the socket, a unit of work will be added to a private
work queue which will first broadcast information about the socket
and then finish the cleanup operation.
Signed-off-by: default avatarCraig Gallek <kraig@google.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 916035dd
#ifndef __SOCK_DIAG_H__
#define __SOCK_DIAG_H__
#include <linux/netlink.h>
#include <linux/user_namespace.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <uapi/linux/sock_diag.h>
struct sk_buff;
......@@ -11,6 +14,7 @@ struct sock;
struct sock_diag_handler {
__u8 family;
int (*dump)(struct sk_buff *skb, struct nlmsghdr *nlh);
int (*get_info)(struct sk_buff *skb, struct sock *sk);
};
int sock_diag_register(const struct sock_diag_handler *h);
......@@ -26,4 +30,42 @@ int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attr);
int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk,
struct sk_buff *skb, int attrtype);
static inline
enum sknetlink_groups sock_diag_destroy_group(const struct sock *sk)
{
switch (sk->sk_family) {
case AF_INET:
switch (sk->sk_protocol) {
case IPPROTO_TCP:
return SKNLGRP_INET_TCP_DESTROY;
case IPPROTO_UDP:
return SKNLGRP_INET_UDP_DESTROY;
default:
return SKNLGRP_NONE;
}
case AF_INET6:
switch (sk->sk_protocol) {
case IPPROTO_TCP:
return SKNLGRP_INET6_TCP_DESTROY;
case IPPROTO_UDP:
return SKNLGRP_INET6_UDP_DESTROY;
default:
return SKNLGRP_NONE;
}
default:
return SKNLGRP_NONE;
}
}
static inline
bool sock_diag_has_destroy_listeners(const struct sock *sk)
{
const struct net *n = sock_net(sk);
const enum sknetlink_groups group = sock_diag_destroy_group(sk);
return group != SKNLGRP_NONE && n->diag_nlsk &&
netlink_has_listeners(n->diag_nlsk, group);
}
void sock_diag_broadcast_destroy(struct sock *sk);
#endif
......@@ -1518,6 +1518,7 @@ static inline void unlock_sock_fast(struct sock *sk, bool slow)
struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
struct proto *prot, int kern);
void sk_free(struct sock *sk);
void sk_destruct(struct sock *sk);
struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority);
struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
......
......@@ -23,4 +23,14 @@ enum {
SK_MEMINFO_VARS,
};
enum sknetlink_groups {
SKNLGRP_NONE,
SKNLGRP_INET_TCP_DESTROY,
SKNLGRP_INET_UDP_DESTROY,
SKNLGRP_INET6_TCP_DESTROY,
SKNLGRP_INET6_UDP_DESTROY,
__SKNLGRP_MAX,
};
#define SKNLGRP_MAX (__SKNLGRP_MAX - 1)
#endif /* _UAPI__SOCK_DIAG_H__ */
......@@ -131,6 +131,7 @@
#include <linux/ipsec.h>
#include <net/cls_cgroup.h>
#include <net/netprio_cgroup.h>
#include <linux/sock_diag.h>
#include <linux/filter.h>
......@@ -1423,7 +1424,7 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
}
EXPORT_SYMBOL(sk_alloc);
static void __sk_free(struct sock *sk)
void sk_destruct(struct sock *sk)
{
struct sk_filter *filter;
......@@ -1451,6 +1452,14 @@ static void __sk_free(struct sock *sk)
sk_prot_free(sk->sk_prot_creator, sk);
}
static void __sk_free(struct sock *sk)
{
if (unlikely(sock_diag_has_destroy_listeners(sk)))
sock_diag_broadcast_destroy(sk);
else
sk_destruct(sk);
}
void sk_free(struct sock *sk)
{
/*
......
......@@ -5,6 +5,9 @@
#include <net/net_namespace.h>
#include <linux/module.h>
#include <net/sock.h>
#include <linux/kernel.h>
#include <linux/tcp.h>
#include <linux/workqueue.h>
#include <linux/inet_diag.h>
#include <linux/sock_diag.h>
......@@ -12,6 +15,7 @@
static const struct sock_diag_handler *sock_diag_handlers[AF_MAX];
static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
static DEFINE_MUTEX(sock_diag_table_mutex);
static struct workqueue_struct *broadcast_wq;
static u64 sock_gen_cookie(struct sock *sk)
{
......@@ -101,6 +105,62 @@ out:
}
EXPORT_SYMBOL(sock_diag_put_filterinfo);
struct broadcast_sk {
struct sock *sk;
struct work_struct work;
};
static size_t sock_diag_nlmsg_size(void)
{
return NLMSG_ALIGN(sizeof(struct inet_diag_msg)
+ nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */
+ nla_total_size(sizeof(struct tcp_info))); /* INET_DIAG_INFO */
}
static void sock_diag_broadcast_destroy_work(struct work_struct *work)
{
struct broadcast_sk *bsk =
container_of(work, struct broadcast_sk, work);
struct sock *sk = bsk->sk;
const struct sock_diag_handler *hndl;
struct sk_buff *skb;
const enum sknetlink_groups group = sock_diag_destroy_group(sk);
int err = -1;
WARN_ON(group == SKNLGRP_NONE);
skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL);
if (!skb)
goto out;
mutex_lock(&sock_diag_table_mutex);
hndl = sock_diag_handlers[sk->sk_family];
if (hndl && hndl->get_info)
err = hndl->get_info(skb, sk);
mutex_unlock(&sock_diag_table_mutex);
if (!err)
nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group,
GFP_KERNEL);
else
kfree_skb(skb);
out:
sk_destruct(sk);
kfree(bsk);
}
void sock_diag_broadcast_destroy(struct sock *sk)
{
/* Note, this function is often called from an interrupt context. */
struct broadcast_sk *bsk =
kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC);
if (!bsk)
return sk_destruct(sk);
bsk->sk = sk;
INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work);
queue_work(broadcast_wq, &bsk->work);
}
void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
{
mutex_lock(&sock_diag_table_mutex);
......@@ -211,10 +271,32 @@ static void sock_diag_rcv(struct sk_buff *skb)
mutex_unlock(&sock_diag_mutex);
}
static int sock_diag_bind(struct net *net, int group)
{
switch (group) {
case SKNLGRP_INET_TCP_DESTROY:
case SKNLGRP_INET_UDP_DESTROY:
if (!sock_diag_handlers[AF_INET])
request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
NETLINK_SOCK_DIAG, AF_INET);
break;
case SKNLGRP_INET6_TCP_DESTROY:
case SKNLGRP_INET6_UDP_DESTROY:
if (!sock_diag_handlers[AF_INET6])
request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
NETLINK_SOCK_DIAG, AF_INET);
break;
}
return 0;
}
static int __net_init diag_net_init(struct net *net)
{
struct netlink_kernel_cfg cfg = {
.groups = SKNLGRP_MAX,
.input = sock_diag_rcv,
.bind = sock_diag_bind,
.flags = NL_CFG_F_NONROOT_RECV,
};
net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg);
......@@ -234,12 +316,15 @@ static struct pernet_operations diag_net_ops = {
static int __init sock_diag_init(void)
{
broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0);
BUG_ON(!broadcast_wq);
return register_pernet_subsys(&diag_net_ops);
}
static void __exit sock_diag_exit(void)
{
unregister_pernet_subsys(&diag_net_ops);
destroy_workqueue(broadcast_wq);
}
module_init(sock_diag_init);
......
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