![Wang Chen](/assets/img/avatar_default.png)
We already have a variable, which has the same capability. Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1994 lines
44 KiB
C
1994 lines
44 KiB
C
/*
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* NETLINK Kernel-user communication protocol.
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*
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* Authors: Alan Cox <alan@redhat.com>
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* Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
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* added netlink_proto_exit
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* Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
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* use nlk_sk, as sk->protinfo is on a diet 8)
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* Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
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* - inc module use count of module that owns
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* the kernel socket in case userspace opens
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* socket of same protocol
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* - remove all module support, since netlink is
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* mandatory if CONFIG_NET=y these days
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*/
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#include <linux/module.h>
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#include <linux/capability.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/stat.h>
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#include <linux/socket.h>
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#include <linux/un.h>
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#include <linux/fcntl.h>
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#include <linux/termios.h>
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#include <linux/sockios.h>
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#include <linux/net.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <asm/uaccess.h>
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#include <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/rtnetlink.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/notifier.h>
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#include <linux/security.h>
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#include <linux/jhash.h>
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#include <linux/jiffies.h>
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#include <linux/random.h>
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#include <linux/bitops.h>
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#include <linux/mm.h>
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#include <linux/types.h>
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#include <linux/audit.h>
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#include <linux/mutex.h>
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#include <net/net_namespace.h>
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#include <net/sock.h>
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#include <net/scm.h>
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#include <net/netlink.h>
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#define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
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#define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long))
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struct netlink_sock {
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/* struct sock has to be the first member of netlink_sock */
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struct sock sk;
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u32 pid;
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u32 dst_pid;
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u32 dst_group;
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u32 flags;
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u32 subscriptions;
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u32 ngroups;
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unsigned long *groups;
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unsigned long state;
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wait_queue_head_t wait;
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struct netlink_callback *cb;
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struct mutex *cb_mutex;
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struct mutex cb_def_mutex;
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void (*netlink_rcv)(struct sk_buff *skb);
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struct module *module;
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};
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#define NETLINK_KERNEL_SOCKET 0x1
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#define NETLINK_RECV_PKTINFO 0x2
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static inline struct netlink_sock *nlk_sk(struct sock *sk)
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{
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return container_of(sk, struct netlink_sock, sk);
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}
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static inline int netlink_is_kernel(struct sock *sk)
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{
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return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
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}
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struct nl_pid_hash {
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struct hlist_head *table;
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unsigned long rehash_time;
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unsigned int mask;
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unsigned int shift;
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unsigned int entries;
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unsigned int max_shift;
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u32 rnd;
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};
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struct netlink_table {
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struct nl_pid_hash hash;
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struct hlist_head mc_list;
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unsigned long *listeners;
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unsigned int nl_nonroot;
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unsigned int groups;
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struct mutex *cb_mutex;
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struct module *module;
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int registered;
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};
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static struct netlink_table *nl_table;
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static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
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static int netlink_dump(struct sock *sk);
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static void netlink_destroy_callback(struct netlink_callback *cb);
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static DEFINE_RWLOCK(nl_table_lock);
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static atomic_t nl_table_users = ATOMIC_INIT(0);
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static ATOMIC_NOTIFIER_HEAD(netlink_chain);
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static u32 netlink_group_mask(u32 group)
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{
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return group ? 1 << (group - 1) : 0;
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}
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static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
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{
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return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
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}
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static void netlink_sock_destruct(struct sock *sk)
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{
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struct netlink_sock *nlk = nlk_sk(sk);
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if (nlk->cb) {
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if (nlk->cb->done)
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nlk->cb->done(nlk->cb);
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netlink_destroy_callback(nlk->cb);
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}
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skb_queue_purge(&sk->sk_receive_queue);
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if (!sock_flag(sk, SOCK_DEAD)) {
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printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
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return;
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}
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BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
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BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
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BUG_TRAP(!nlk_sk(sk)->groups);
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}
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/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
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* SMP. Look, when several writers sleep and reader wakes them up, all but one
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* immediately hit write lock and grab all the cpus. Exclusive sleep solves
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* this, _but_ remember, it adds useless work on UP machines.
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*/
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static void netlink_table_grab(void)
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__acquires(nl_table_lock)
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{
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write_lock_irq(&nl_table_lock);
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if (atomic_read(&nl_table_users)) {
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DECLARE_WAITQUEUE(wait, current);
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add_wait_queue_exclusive(&nl_table_wait, &wait);
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for (;;) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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if (atomic_read(&nl_table_users) == 0)
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break;
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write_unlock_irq(&nl_table_lock);
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schedule();
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write_lock_irq(&nl_table_lock);
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}
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__set_current_state(TASK_RUNNING);
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remove_wait_queue(&nl_table_wait, &wait);
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}
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}
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static void netlink_table_ungrab(void)
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__releases(nl_table_lock)
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{
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write_unlock_irq(&nl_table_lock);
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wake_up(&nl_table_wait);
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}
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static inline void
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netlink_lock_table(void)
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{
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/* read_lock() synchronizes us to netlink_table_grab */
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read_lock(&nl_table_lock);
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atomic_inc(&nl_table_users);
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read_unlock(&nl_table_lock);
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}
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static inline void
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netlink_unlock_table(void)
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{
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if (atomic_dec_and_test(&nl_table_users))
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wake_up(&nl_table_wait);
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}
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static inline struct sock *netlink_lookup(struct net *net, int protocol,
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u32 pid)
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{
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struct nl_pid_hash *hash = &nl_table[protocol].hash;
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struct hlist_head *head;
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struct sock *sk;
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struct hlist_node *node;
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read_lock(&nl_table_lock);
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head = nl_pid_hashfn(hash, pid);
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sk_for_each(sk, node, head) {
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if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->pid == pid)) {
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sock_hold(sk);
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goto found;
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}
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}
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sk = NULL;
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found:
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read_unlock(&nl_table_lock);
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return sk;
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}
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static inline struct hlist_head *nl_pid_hash_zalloc(size_t size)
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{
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if (size <= PAGE_SIZE)
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return kzalloc(size, GFP_ATOMIC);
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else
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return (struct hlist_head *)
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__get_free_pages(GFP_ATOMIC | __GFP_ZERO,
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get_order(size));
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}
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static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
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{
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if (size <= PAGE_SIZE)
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kfree(table);
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else
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free_pages((unsigned long)table, get_order(size));
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}
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static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
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{
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unsigned int omask, mask, shift;
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size_t osize, size;
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struct hlist_head *otable, *table;
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int i;
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omask = mask = hash->mask;
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osize = size = (mask + 1) * sizeof(*table);
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shift = hash->shift;
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if (grow) {
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if (++shift > hash->max_shift)
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return 0;
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mask = mask * 2 + 1;
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size *= 2;
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}
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table = nl_pid_hash_zalloc(size);
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if (!table)
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return 0;
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otable = hash->table;
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hash->table = table;
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hash->mask = mask;
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hash->shift = shift;
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get_random_bytes(&hash->rnd, sizeof(hash->rnd));
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for (i = 0; i <= omask; i++) {
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struct sock *sk;
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struct hlist_node *node, *tmp;
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sk_for_each_safe(sk, node, tmp, &otable[i])
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__sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
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}
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nl_pid_hash_free(otable, osize);
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hash->rehash_time = jiffies + 10 * 60 * HZ;
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return 1;
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}
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static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
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{
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int avg = hash->entries >> hash->shift;
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if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
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return 1;
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if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
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nl_pid_hash_rehash(hash, 0);
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return 1;
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}
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return 0;
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}
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static const struct proto_ops netlink_ops;
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static void
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netlink_update_listeners(struct sock *sk)
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{
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struct netlink_table *tbl = &nl_table[sk->sk_protocol];
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struct hlist_node *node;
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unsigned long mask;
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unsigned int i;
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for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
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mask = 0;
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sk_for_each_bound(sk, node, &tbl->mc_list) {
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if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
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mask |= nlk_sk(sk)->groups[i];
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}
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tbl->listeners[i] = mask;
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}
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/* this function is only called with the netlink table "grabbed", which
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* makes sure updates are visible before bind or setsockopt return. */
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}
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static int netlink_insert(struct sock *sk, struct net *net, u32 pid)
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{
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struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
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struct hlist_head *head;
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int err = -EADDRINUSE;
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struct sock *osk;
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struct hlist_node *node;
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int len;
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netlink_table_grab();
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head = nl_pid_hashfn(hash, pid);
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len = 0;
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sk_for_each(osk, node, head) {
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if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->pid == pid))
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break;
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len++;
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}
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if (node)
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goto err;
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err = -EBUSY;
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if (nlk_sk(sk)->pid)
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goto err;
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err = -ENOMEM;
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if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
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goto err;
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if (len && nl_pid_hash_dilute(hash, len))
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head = nl_pid_hashfn(hash, pid);
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hash->entries++;
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nlk_sk(sk)->pid = pid;
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sk_add_node(sk, head);
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err = 0;
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err:
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netlink_table_ungrab();
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return err;
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}
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static void netlink_remove(struct sock *sk)
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{
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netlink_table_grab();
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if (sk_del_node_init(sk))
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nl_table[sk->sk_protocol].hash.entries--;
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if (nlk_sk(sk)->subscriptions)
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__sk_del_bind_node(sk);
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netlink_table_ungrab();
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}
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static struct proto netlink_proto = {
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.name = "NETLINK",
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.owner = THIS_MODULE,
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.obj_size = sizeof(struct netlink_sock),
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};
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static int __netlink_create(struct net *net, struct socket *sock,
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struct mutex *cb_mutex, int protocol)
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{
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struct sock *sk;
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struct netlink_sock *nlk;
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sock->ops = &netlink_ops;
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sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
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if (!sk)
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return -ENOMEM;
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sock_init_data(sock, sk);
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nlk = nlk_sk(sk);
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if (cb_mutex)
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nlk->cb_mutex = cb_mutex;
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else {
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nlk->cb_mutex = &nlk->cb_def_mutex;
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mutex_init(nlk->cb_mutex);
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}
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init_waitqueue_head(&nlk->wait);
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sk->sk_destruct = netlink_sock_destruct;
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sk->sk_protocol = protocol;
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return 0;
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}
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static int netlink_create(struct net *net, struct socket *sock, int protocol)
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{
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struct module *module = NULL;
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struct mutex *cb_mutex;
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struct netlink_sock *nlk;
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int err = 0;
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sock->state = SS_UNCONNECTED;
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if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
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return -ESOCKTNOSUPPORT;
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if (protocol < 0 || protocol >= MAX_LINKS)
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return -EPROTONOSUPPORT;
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netlink_lock_table();
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#ifdef CONFIG_KMOD
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if (!nl_table[protocol].registered) {
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netlink_unlock_table();
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request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
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netlink_lock_table();
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}
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#endif
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if (nl_table[protocol].registered &&
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try_module_get(nl_table[protocol].module))
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module = nl_table[protocol].module;
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cb_mutex = nl_table[protocol].cb_mutex;
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netlink_unlock_table();
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err = __netlink_create(net, sock, cb_mutex, protocol);
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if (err < 0)
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goto out_module;
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nlk = nlk_sk(sock->sk);
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nlk->module = module;
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out:
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return err;
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out_module:
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module_put(module);
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goto out;
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}
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static int netlink_release(struct socket *sock)
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{
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struct sock *sk = sock->sk;
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struct netlink_sock *nlk;
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if (!sk)
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return 0;
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netlink_remove(sk);
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sock_orphan(sk);
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nlk = nlk_sk(sk);
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/*
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* OK. Socket is unlinked, any packets that arrive now
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* will be purged.
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*/
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sock->sk = NULL;
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wake_up_interruptible_all(&nlk->wait);
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skb_queue_purge(&sk->sk_write_queue);
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if (nlk->pid && !nlk->subscriptions) {
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struct netlink_notify n = {
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.net = sock_net(sk),
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.protocol = sk->sk_protocol,
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.pid = nlk->pid,
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};
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atomic_notifier_call_chain(&netlink_chain,
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NETLINK_URELEASE, &n);
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}
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module_put(nlk->module);
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netlink_table_grab();
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if (netlink_is_kernel(sk)) {
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BUG_ON(nl_table[sk->sk_protocol].registered == 0);
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if (--nl_table[sk->sk_protocol].registered == 0) {
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kfree(nl_table[sk->sk_protocol].listeners);
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nl_table[sk->sk_protocol].module = NULL;
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nl_table[sk->sk_protocol].registered = 0;
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}
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} else if (nlk->subscriptions)
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netlink_update_listeners(sk);
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netlink_table_ungrab();
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kfree(nlk->groups);
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nlk->groups = NULL;
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sock_put(sk);
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return 0;
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}
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static int netlink_autobind(struct socket *sock)
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{
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struct sock *sk = sock->sk;
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struct net *net = sock_net(sk);
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struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
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struct hlist_head *head;
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struct sock *osk;
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struct hlist_node *node;
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s32 pid = current->tgid;
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int err;
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static s32 rover = -4097;
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retry:
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cond_resched();
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netlink_table_grab();
|
|
head = nl_pid_hashfn(hash, pid);
|
|
sk_for_each(osk, node, head) {
|
|
if (!net_eq(sock_net(osk), net))
|
|
continue;
|
|
if (nlk_sk(osk)->pid == pid) {
|
|
/* Bind collision, search negative pid values. */
|
|
pid = rover--;
|
|
if (rover > -4097)
|
|
rover = -4097;
|
|
netlink_table_ungrab();
|
|
goto retry;
|
|
}
|
|
}
|
|
netlink_table_ungrab();
|
|
|
|
err = netlink_insert(sk, net, pid);
|
|
if (err == -EADDRINUSE)
|
|
goto retry;
|
|
|
|
/* If 2 threads race to autobind, that is fine. */
|
|
if (err == -EBUSY)
|
|
err = 0;
|
|
|
|
return err;
|
|
}
|
|
|
|
static inline int netlink_capable(struct socket *sock, unsigned int flag)
|
|
{
|
|
return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
|
|
capable(CAP_NET_ADMIN);
|
|
}
|
|
|
|
static void
|
|
netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
|
|
{
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
|
|
if (nlk->subscriptions && !subscriptions)
|
|
__sk_del_bind_node(sk);
|
|
else if (!nlk->subscriptions && subscriptions)
|
|
sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
|
|
nlk->subscriptions = subscriptions;
|
|
}
|
|
|
|
static int netlink_realloc_groups(struct sock *sk)
|
|
{
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
unsigned int groups;
|
|
unsigned long *new_groups;
|
|
int err = 0;
|
|
|
|
netlink_table_grab();
|
|
|
|
groups = nl_table[sk->sk_protocol].groups;
|
|
if (!nl_table[sk->sk_protocol].registered) {
|
|
err = -ENOENT;
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (nlk->ngroups >= groups)
|
|
goto out_unlock;
|
|
|
|
new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
|
|
if (new_groups == NULL) {
|
|
err = -ENOMEM;
|
|
goto out_unlock;
|
|
}
|
|
memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
|
|
NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
|
|
|
|
nlk->groups = new_groups;
|
|
nlk->ngroups = groups;
|
|
out_unlock:
|
|
netlink_table_ungrab();
|
|
return err;
|
|
}
|
|
|
|
static int netlink_bind(struct socket *sock, struct sockaddr *addr,
|
|
int addr_len)
|
|
{
|
|
struct sock *sk = sock->sk;
|
|
struct net *net = sock_net(sk);
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
|
|
int err;
|
|
|
|
if (nladdr->nl_family != AF_NETLINK)
|
|
return -EINVAL;
|
|
|
|
/* Only superuser is allowed to listen multicasts */
|
|
if (nladdr->nl_groups) {
|
|
if (!netlink_capable(sock, NL_NONROOT_RECV))
|
|
return -EPERM;
|
|
err = netlink_realloc_groups(sk);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
if (nlk->pid) {
|
|
if (nladdr->nl_pid != nlk->pid)
|
|
return -EINVAL;
|
|
} else {
|
|
err = nladdr->nl_pid ?
|
|
netlink_insert(sk, net, nladdr->nl_pid) :
|
|
netlink_autobind(sock);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
|
|
return 0;
|
|
|
|
netlink_table_grab();
|
|
netlink_update_subscriptions(sk, nlk->subscriptions +
|
|
hweight32(nladdr->nl_groups) -
|
|
hweight32(nlk->groups[0]));
|
|
nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
|
|
netlink_update_listeners(sk);
|
|
netlink_table_ungrab();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int netlink_connect(struct socket *sock, struct sockaddr *addr,
|
|
int alen, int flags)
|
|
{
|
|
int err = 0;
|
|
struct sock *sk = sock->sk;
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
|
|
|
|
if (addr->sa_family == AF_UNSPEC) {
|
|
sk->sk_state = NETLINK_UNCONNECTED;
|
|
nlk->dst_pid = 0;
|
|
nlk->dst_group = 0;
|
|
return 0;
|
|
}
|
|
if (addr->sa_family != AF_NETLINK)
|
|
return -EINVAL;
|
|
|
|
/* Only superuser is allowed to send multicasts */
|
|
if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
|
|
return -EPERM;
|
|
|
|
if (!nlk->pid)
|
|
err = netlink_autobind(sock);
|
|
|
|
if (err == 0) {
|
|
sk->sk_state = NETLINK_CONNECTED;
|
|
nlk->dst_pid = nladdr->nl_pid;
|
|
nlk->dst_group = ffs(nladdr->nl_groups);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int netlink_getname(struct socket *sock, struct sockaddr *addr,
|
|
int *addr_len, int peer)
|
|
{
|
|
struct sock *sk = sock->sk;
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
|
|
|
|
nladdr->nl_family = AF_NETLINK;
|
|
nladdr->nl_pad = 0;
|
|
*addr_len = sizeof(*nladdr);
|
|
|
|
if (peer) {
|
|
nladdr->nl_pid = nlk->dst_pid;
|
|
nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
|
|
} else {
|
|
nladdr->nl_pid = nlk->pid;
|
|
nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void netlink_overrun(struct sock *sk)
|
|
{
|
|
if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
|
|
sk->sk_err = ENOBUFS;
|
|
sk->sk_error_report(sk);
|
|
}
|
|
}
|
|
|
|
static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
|
|
{
|
|
struct sock *sock;
|
|
struct netlink_sock *nlk;
|
|
|
|
sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid);
|
|
if (!sock)
|
|
return ERR_PTR(-ECONNREFUSED);
|
|
|
|
/* Don't bother queuing skb if kernel socket has no input function */
|
|
nlk = nlk_sk(sock);
|
|
if (sock->sk_state == NETLINK_CONNECTED &&
|
|
nlk->dst_pid != nlk_sk(ssk)->pid) {
|
|
sock_put(sock);
|
|
return ERR_PTR(-ECONNREFUSED);
|
|
}
|
|
return sock;
|
|
}
|
|
|
|
struct sock *netlink_getsockbyfilp(struct file *filp)
|
|
{
|
|
struct inode *inode = filp->f_path.dentry->d_inode;
|
|
struct sock *sock;
|
|
|
|
if (!S_ISSOCK(inode->i_mode))
|
|
return ERR_PTR(-ENOTSOCK);
|
|
|
|
sock = SOCKET_I(inode)->sk;
|
|
if (sock->sk_family != AF_NETLINK)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
sock_hold(sock);
|
|
return sock;
|
|
}
|
|
|
|
/*
|
|
* Attach a skb to a netlink socket.
|
|
* The caller must hold a reference to the destination socket. On error, the
|
|
* reference is dropped. The skb is not send to the destination, just all
|
|
* all error checks are performed and memory in the queue is reserved.
|
|
* Return values:
|
|
* < 0: error. skb freed, reference to sock dropped.
|
|
* 0: continue
|
|
* 1: repeat lookup - reference dropped while waiting for socket memory.
|
|
*/
|
|
int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock,
|
|
long *timeo, struct sock *ssk)
|
|
{
|
|
struct netlink_sock *nlk;
|
|
|
|
nlk = nlk_sk(sk);
|
|
|
|
if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
|
|
test_bit(0, &nlk->state)) {
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
if (!*timeo) {
|
|
if (!ssk || netlink_is_kernel(ssk))
|
|
netlink_overrun(sk);
|
|
sock_put(sk);
|
|
kfree_skb(skb);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
__set_current_state(TASK_INTERRUPTIBLE);
|
|
add_wait_queue(&nlk->wait, &wait);
|
|
|
|
if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
|
|
test_bit(0, &nlk->state)) &&
|
|
!sock_flag(sk, SOCK_DEAD))
|
|
*timeo = schedule_timeout(*timeo);
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
remove_wait_queue(&nlk->wait, &wait);
|
|
sock_put(sk);
|
|
|
|
if (signal_pending(current)) {
|
|
kfree_skb(skb);
|
|
return sock_intr_errno(*timeo);
|
|
}
|
|
return 1;
|
|
}
|
|
skb_set_owner_r(skb, sk);
|
|
return 0;
|
|
}
|
|
|
|
int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
int len = skb->len;
|
|
|
|
skb_queue_tail(&sk->sk_receive_queue, skb);
|
|
sk->sk_data_ready(sk, len);
|
|
sock_put(sk);
|
|
return len;
|
|
}
|
|
|
|
void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
kfree_skb(skb);
|
|
sock_put(sk);
|
|
}
|
|
|
|
static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
|
|
gfp_t allocation)
|
|
{
|
|
int delta;
|
|
|
|
skb_orphan(skb);
|
|
|
|
delta = skb->end - skb->tail;
|
|
if (delta * 2 < skb->truesize)
|
|
return skb;
|
|
|
|
if (skb_shared(skb)) {
|
|
struct sk_buff *nskb = skb_clone(skb, allocation);
|
|
if (!nskb)
|
|
return skb;
|
|
kfree_skb(skb);
|
|
skb = nskb;
|
|
}
|
|
|
|
if (!pskb_expand_head(skb, 0, -delta, allocation))
|
|
skb->truesize -= delta;
|
|
|
|
return skb;
|
|
}
|
|
|
|
static inline void netlink_rcv_wake(struct sock *sk)
|
|
{
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
|
|
if (skb_queue_empty(&sk->sk_receive_queue))
|
|
clear_bit(0, &nlk->state);
|
|
if (!test_bit(0, &nlk->state))
|
|
wake_up_interruptible(&nlk->wait);
|
|
}
|
|
|
|
static inline int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
int ret;
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
|
|
ret = -ECONNREFUSED;
|
|
if (nlk->netlink_rcv != NULL) {
|
|
ret = skb->len;
|
|
skb_set_owner_r(skb, sk);
|
|
nlk->netlink_rcv(skb);
|
|
}
|
|
kfree_skb(skb);
|
|
sock_put(sk);
|
|
return ret;
|
|
}
|
|
|
|
int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
|
|
u32 pid, int nonblock)
|
|
{
|
|
struct sock *sk;
|
|
int err;
|
|
long timeo;
|
|
|
|
skb = netlink_trim(skb, gfp_any());
|
|
|
|
timeo = sock_sndtimeo(ssk, nonblock);
|
|
retry:
|
|
sk = netlink_getsockbypid(ssk, pid);
|
|
if (IS_ERR(sk)) {
|
|
kfree_skb(skb);
|
|
return PTR_ERR(sk);
|
|
}
|
|
if (netlink_is_kernel(sk))
|
|
return netlink_unicast_kernel(sk, skb);
|
|
|
|
if (sk_filter(sk, skb)) {
|
|
err = skb->len;
|
|
kfree_skb(skb);
|
|
sock_put(sk);
|
|
return err;
|
|
}
|
|
|
|
err = netlink_attachskb(sk, skb, nonblock, &timeo, ssk);
|
|
if (err == 1)
|
|
goto retry;
|
|
if (err)
|
|
return err;
|
|
|
|
return netlink_sendskb(sk, skb);
|
|
}
|
|
EXPORT_SYMBOL(netlink_unicast);
|
|
|
|
int netlink_has_listeners(struct sock *sk, unsigned int group)
|
|
{
|
|
int res = 0;
|
|
unsigned long *listeners;
|
|
|
|
BUG_ON(!netlink_is_kernel(sk));
|
|
|
|
rcu_read_lock();
|
|
listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
|
|
|
|
if (group - 1 < nl_table[sk->sk_protocol].groups)
|
|
res = test_bit(group - 1, listeners);
|
|
|
|
rcu_read_unlock();
|
|
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL_GPL(netlink_has_listeners);
|
|
|
|
static inline int netlink_broadcast_deliver(struct sock *sk,
|
|
struct sk_buff *skb)
|
|
{
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
|
|
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
|
|
!test_bit(0, &nlk->state)) {
|
|
skb_set_owner_r(skb, sk);
|
|
skb_queue_tail(&sk->sk_receive_queue, skb);
|
|
sk->sk_data_ready(sk, skb->len);
|
|
return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
struct netlink_broadcast_data {
|
|
struct sock *exclude_sk;
|
|
struct net *net;
|
|
u32 pid;
|
|
u32 group;
|
|
int failure;
|
|
int congested;
|
|
int delivered;
|
|
gfp_t allocation;
|
|
struct sk_buff *skb, *skb2;
|
|
};
|
|
|
|
static inline int do_one_broadcast(struct sock *sk,
|
|
struct netlink_broadcast_data *p)
|
|
{
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
int val;
|
|
|
|
if (p->exclude_sk == sk)
|
|
goto out;
|
|
|
|
if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
|
|
!test_bit(p->group - 1, nlk->groups))
|
|
goto out;
|
|
|
|
if (!net_eq(sock_net(sk), p->net))
|
|
goto out;
|
|
|
|
if (p->failure) {
|
|
netlink_overrun(sk);
|
|
goto out;
|
|
}
|
|
|
|
sock_hold(sk);
|
|
if (p->skb2 == NULL) {
|
|
if (skb_shared(p->skb)) {
|
|
p->skb2 = skb_clone(p->skb, p->allocation);
|
|
} else {
|
|
p->skb2 = skb_get(p->skb);
|
|
/*
|
|
* skb ownership may have been set when
|
|
* delivered to a previous socket.
|
|
*/
|
|
skb_orphan(p->skb2);
|
|
}
|
|
}
|
|
if (p->skb2 == NULL) {
|
|
netlink_overrun(sk);
|
|
/* Clone failed. Notify ALL listeners. */
|
|
p->failure = 1;
|
|
} else if (sk_filter(sk, p->skb2)) {
|
|
kfree_skb(p->skb2);
|
|
p->skb2 = NULL;
|
|
} else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
|
|
netlink_overrun(sk);
|
|
} else {
|
|
p->congested |= val;
|
|
p->delivered = 1;
|
|
p->skb2 = NULL;
|
|
}
|
|
sock_put(sk);
|
|
|
|
out:
|
|
return 0;
|
|
}
|
|
|
|
int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
|
|
u32 group, gfp_t allocation)
|
|
{
|
|
struct net *net = sock_net(ssk);
|
|
struct netlink_broadcast_data info;
|
|
struct hlist_node *node;
|
|
struct sock *sk;
|
|
|
|
skb = netlink_trim(skb, allocation);
|
|
|
|
info.exclude_sk = ssk;
|
|
info.net = net;
|
|
info.pid = pid;
|
|
info.group = group;
|
|
info.failure = 0;
|
|
info.congested = 0;
|
|
info.delivered = 0;
|
|
info.allocation = allocation;
|
|
info.skb = skb;
|
|
info.skb2 = NULL;
|
|
|
|
/* While we sleep in clone, do not allow to change socket list */
|
|
|
|
netlink_lock_table();
|
|
|
|
sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
|
|
do_one_broadcast(sk, &info);
|
|
|
|
kfree_skb(skb);
|
|
|
|
netlink_unlock_table();
|
|
|
|
if (info.skb2)
|
|
kfree_skb(info.skb2);
|
|
|
|
if (info.delivered) {
|
|
if (info.congested && (allocation & __GFP_WAIT))
|
|
yield();
|
|
return 0;
|
|
}
|
|
if (info.failure)
|
|
return -ENOBUFS;
|
|
return -ESRCH;
|
|
}
|
|
EXPORT_SYMBOL(netlink_broadcast);
|
|
|
|
struct netlink_set_err_data {
|
|
struct sock *exclude_sk;
|
|
u32 pid;
|
|
u32 group;
|
|
int code;
|
|
};
|
|
|
|
static inline int do_one_set_err(struct sock *sk,
|
|
struct netlink_set_err_data *p)
|
|
{
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
|
|
if (sk == p->exclude_sk)
|
|
goto out;
|
|
|
|
if (sock_net(sk) != sock_net(p->exclude_sk))
|
|
goto out;
|
|
|
|
if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
|
|
!test_bit(p->group - 1, nlk->groups))
|
|
goto out;
|
|
|
|
sk->sk_err = p->code;
|
|
sk->sk_error_report(sk);
|
|
out:
|
|
return 0;
|
|
}
|
|
|
|
void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
|
|
{
|
|
struct netlink_set_err_data info;
|
|
struct hlist_node *node;
|
|
struct sock *sk;
|
|
|
|
info.exclude_sk = ssk;
|
|
info.pid = pid;
|
|
info.group = group;
|
|
info.code = code;
|
|
|
|
read_lock(&nl_table_lock);
|
|
|
|
sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
|
|
do_one_set_err(sk, &info);
|
|
|
|
read_unlock(&nl_table_lock);
|
|
}
|
|
|
|
/* must be called with netlink table grabbed */
|
|
static void netlink_update_socket_mc(struct netlink_sock *nlk,
|
|
unsigned int group,
|
|
int is_new)
|
|
{
|
|
int old, new = !!is_new, subscriptions;
|
|
|
|
old = test_bit(group - 1, nlk->groups);
|
|
subscriptions = nlk->subscriptions - old + new;
|
|
if (new)
|
|
__set_bit(group - 1, nlk->groups);
|
|
else
|
|
__clear_bit(group - 1, nlk->groups);
|
|
netlink_update_subscriptions(&nlk->sk, subscriptions);
|
|
netlink_update_listeners(&nlk->sk);
|
|
}
|
|
|
|
static int netlink_setsockopt(struct socket *sock, int level, int optname,
|
|
char __user *optval, int optlen)
|
|
{
|
|
struct sock *sk = sock->sk;
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
unsigned int val = 0;
|
|
int err;
|
|
|
|
if (level != SOL_NETLINK)
|
|
return -ENOPROTOOPT;
|
|
|
|
if (optlen >= sizeof(int) &&
|
|
get_user(val, (unsigned int __user *)optval))
|
|
return -EFAULT;
|
|
|
|
switch (optname) {
|
|
case NETLINK_PKTINFO:
|
|
if (val)
|
|
nlk->flags |= NETLINK_RECV_PKTINFO;
|
|
else
|
|
nlk->flags &= ~NETLINK_RECV_PKTINFO;
|
|
err = 0;
|
|
break;
|
|
case NETLINK_ADD_MEMBERSHIP:
|
|
case NETLINK_DROP_MEMBERSHIP: {
|
|
if (!netlink_capable(sock, NL_NONROOT_RECV))
|
|
return -EPERM;
|
|
err = netlink_realloc_groups(sk);
|
|
if (err)
|
|
return err;
|
|
if (!val || val - 1 >= nlk->ngroups)
|
|
return -EINVAL;
|
|
netlink_table_grab();
|
|
netlink_update_socket_mc(nlk, val,
|
|
optname == NETLINK_ADD_MEMBERSHIP);
|
|
netlink_table_ungrab();
|
|
err = 0;
|
|
break;
|
|
}
|
|
default:
|
|
err = -ENOPROTOOPT;
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static int netlink_getsockopt(struct socket *sock, int level, int optname,
|
|
char __user *optval, int __user *optlen)
|
|
{
|
|
struct sock *sk = sock->sk;
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
int len, val, err;
|
|
|
|
if (level != SOL_NETLINK)
|
|
return -ENOPROTOOPT;
|
|
|
|
if (get_user(len, optlen))
|
|
return -EFAULT;
|
|
if (len < 0)
|
|
return -EINVAL;
|
|
|
|
switch (optname) {
|
|
case NETLINK_PKTINFO:
|
|
if (len < sizeof(int))
|
|
return -EINVAL;
|
|
len = sizeof(int);
|
|
val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
|
|
if (put_user(len, optlen) ||
|
|
put_user(val, optval))
|
|
return -EFAULT;
|
|
err = 0;
|
|
break;
|
|
default:
|
|
err = -ENOPROTOOPT;
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
|
|
{
|
|
struct nl_pktinfo info;
|
|
|
|
info.group = NETLINK_CB(skb).dst_group;
|
|
put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
|
|
}
|
|
|
|
static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
|
|
struct msghdr *msg, size_t len)
|
|
{
|
|
struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
|
|
struct sock *sk = sock->sk;
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
struct sockaddr_nl *addr = msg->msg_name;
|
|
u32 dst_pid;
|
|
u32 dst_group;
|
|
struct sk_buff *skb;
|
|
int err;
|
|
struct scm_cookie scm;
|
|
|
|
if (msg->msg_flags&MSG_OOB)
|
|
return -EOPNOTSUPP;
|
|
|
|
if (NULL == siocb->scm)
|
|
siocb->scm = &scm;
|
|
err = scm_send(sock, msg, siocb->scm);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (msg->msg_namelen) {
|
|
if (addr->nl_family != AF_NETLINK)
|
|
return -EINVAL;
|
|
dst_pid = addr->nl_pid;
|
|
dst_group = ffs(addr->nl_groups);
|
|
if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
|
|
return -EPERM;
|
|
} else {
|
|
dst_pid = nlk->dst_pid;
|
|
dst_group = nlk->dst_group;
|
|
}
|
|
|
|
if (!nlk->pid) {
|
|
err = netlink_autobind(sock);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
|
|
err = -EMSGSIZE;
|
|
if (len > sk->sk_sndbuf - 32)
|
|
goto out;
|
|
err = -ENOBUFS;
|
|
skb = alloc_skb(len, GFP_KERNEL);
|
|
if (skb == NULL)
|
|
goto out;
|
|
|
|
NETLINK_CB(skb).pid = nlk->pid;
|
|
NETLINK_CB(skb).dst_group = dst_group;
|
|
NETLINK_CB(skb).loginuid = audit_get_loginuid(current);
|
|
NETLINK_CB(skb).sessionid = audit_get_sessionid(current);
|
|
security_task_getsecid(current, &(NETLINK_CB(skb).sid));
|
|
memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
|
|
|
|
/* What can I do? Netlink is asynchronous, so that
|
|
we will have to save current capabilities to
|
|
check them, when this message will be delivered
|
|
to corresponding kernel module. --ANK (980802)
|
|
*/
|
|
|
|
err = -EFAULT;
|
|
if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
|
|
kfree_skb(skb);
|
|
goto out;
|
|
}
|
|
|
|
err = security_netlink_send(sk, skb);
|
|
if (err) {
|
|
kfree_skb(skb);
|
|
goto out;
|
|
}
|
|
|
|
if (dst_group) {
|
|
atomic_inc(&skb->users);
|
|
netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
|
|
}
|
|
err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
|
|
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
|
|
struct msghdr *msg, size_t len,
|
|
int flags)
|
|
{
|
|
struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
|
|
struct scm_cookie scm;
|
|
struct sock *sk = sock->sk;
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
int noblock = flags&MSG_DONTWAIT;
|
|
size_t copied;
|
|
struct sk_buff *skb;
|
|
int err;
|
|
|
|
if (flags&MSG_OOB)
|
|
return -EOPNOTSUPP;
|
|
|
|
copied = 0;
|
|
|
|
skb = skb_recv_datagram(sk, flags, noblock, &err);
|
|
if (skb == NULL)
|
|
goto out;
|
|
|
|
msg->msg_namelen = 0;
|
|
|
|
copied = skb->len;
|
|
if (len < copied) {
|
|
msg->msg_flags |= MSG_TRUNC;
|
|
copied = len;
|
|
}
|
|
|
|
skb_reset_transport_header(skb);
|
|
err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
|
|
|
|
if (msg->msg_name) {
|
|
struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
|
|
addr->nl_family = AF_NETLINK;
|
|
addr->nl_pad = 0;
|
|
addr->nl_pid = NETLINK_CB(skb).pid;
|
|
addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
|
|
msg->msg_namelen = sizeof(*addr);
|
|
}
|
|
|
|
if (nlk->flags & NETLINK_RECV_PKTINFO)
|
|
netlink_cmsg_recv_pktinfo(msg, skb);
|
|
|
|
if (NULL == siocb->scm) {
|
|
memset(&scm, 0, sizeof(scm));
|
|
siocb->scm = &scm;
|
|
}
|
|
siocb->scm->creds = *NETLINK_CREDS(skb);
|
|
if (flags & MSG_TRUNC)
|
|
copied = skb->len;
|
|
skb_free_datagram(sk, skb);
|
|
|
|
if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
|
|
netlink_dump(sk);
|
|
|
|
scm_recv(sock, msg, siocb->scm, flags);
|
|
out:
|
|
netlink_rcv_wake(sk);
|
|
return err ? : copied;
|
|
}
|
|
|
|
static void netlink_data_ready(struct sock *sk, int len)
|
|
{
|
|
BUG();
|
|
}
|
|
|
|
/*
|
|
* We export these functions to other modules. They provide a
|
|
* complete set of kernel non-blocking support for message
|
|
* queueing.
|
|
*/
|
|
|
|
struct sock *
|
|
netlink_kernel_create(struct net *net, int unit, unsigned int groups,
|
|
void (*input)(struct sk_buff *skb),
|
|
struct mutex *cb_mutex, struct module *module)
|
|
{
|
|
struct socket *sock;
|
|
struct sock *sk;
|
|
struct netlink_sock *nlk;
|
|
unsigned long *listeners = NULL;
|
|
|
|
BUG_ON(!nl_table);
|
|
|
|
if (unit < 0 || unit >= MAX_LINKS)
|
|
return NULL;
|
|
|
|
if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
|
|
return NULL;
|
|
|
|
/*
|
|
* We have to just have a reference on the net from sk, but don't
|
|
* get_net it. Besides, we cannot get and then put the net here.
|
|
* So we create one inside init_net and the move it to net.
|
|
*/
|
|
|
|
if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
|
|
goto out_sock_release_nosk;
|
|
|
|
sk = sock->sk;
|
|
sk_change_net(sk, net);
|
|
|
|
if (groups < 32)
|
|
groups = 32;
|
|
|
|
listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
|
|
if (!listeners)
|
|
goto out_sock_release;
|
|
|
|
sk->sk_data_ready = netlink_data_ready;
|
|
if (input)
|
|
nlk_sk(sk)->netlink_rcv = input;
|
|
|
|
if (netlink_insert(sk, net, 0))
|
|
goto out_sock_release;
|
|
|
|
nlk = nlk_sk(sk);
|
|
nlk->flags |= NETLINK_KERNEL_SOCKET;
|
|
|
|
netlink_table_grab();
|
|
if (!nl_table[unit].registered) {
|
|
nl_table[unit].groups = groups;
|
|
nl_table[unit].listeners = listeners;
|
|
nl_table[unit].cb_mutex = cb_mutex;
|
|
nl_table[unit].module = module;
|
|
nl_table[unit].registered = 1;
|
|
} else {
|
|
kfree(listeners);
|
|
nl_table[unit].registered++;
|
|
}
|
|
netlink_table_ungrab();
|
|
return sk;
|
|
|
|
out_sock_release:
|
|
kfree(listeners);
|
|
netlink_kernel_release(sk);
|
|
return NULL;
|
|
|
|
out_sock_release_nosk:
|
|
sock_release(sock);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(netlink_kernel_create);
|
|
|
|
|
|
void
|
|
netlink_kernel_release(struct sock *sk)
|
|
{
|
|
sk_release_kernel(sk);
|
|
}
|
|
EXPORT_SYMBOL(netlink_kernel_release);
|
|
|
|
|
|
/**
|
|
* netlink_change_ngroups - change number of multicast groups
|
|
*
|
|
* This changes the number of multicast groups that are available
|
|
* on a certain netlink family. Note that it is not possible to
|
|
* change the number of groups to below 32. Also note that it does
|
|
* not implicitly call netlink_clear_multicast_users() when the
|
|
* number of groups is reduced.
|
|
*
|
|
* @sk: The kernel netlink socket, as returned by netlink_kernel_create().
|
|
* @groups: The new number of groups.
|
|
*/
|
|
int netlink_change_ngroups(struct sock *sk, unsigned int groups)
|
|
{
|
|
unsigned long *listeners, *old = NULL;
|
|
struct netlink_table *tbl = &nl_table[sk->sk_protocol];
|
|
int err = 0;
|
|
|
|
if (groups < 32)
|
|
groups = 32;
|
|
|
|
netlink_table_grab();
|
|
if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
|
|
listeners = kzalloc(NLGRPSZ(groups), GFP_ATOMIC);
|
|
if (!listeners) {
|
|
err = -ENOMEM;
|
|
goto out_ungrab;
|
|
}
|
|
old = tbl->listeners;
|
|
memcpy(listeners, old, NLGRPSZ(tbl->groups));
|
|
rcu_assign_pointer(tbl->listeners, listeners);
|
|
}
|
|
tbl->groups = groups;
|
|
|
|
out_ungrab:
|
|
netlink_table_ungrab();
|
|
synchronize_rcu();
|
|
kfree(old);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL(netlink_change_ngroups);
|
|
|
|
/**
|
|
* netlink_clear_multicast_users - kick off multicast listeners
|
|
*
|
|
* This function removes all listeners from the given group.
|
|
* @ksk: The kernel netlink socket, as returned by
|
|
* netlink_kernel_create().
|
|
* @group: The multicast group to clear.
|
|
*/
|
|
void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
|
|
{
|
|
struct sock *sk;
|
|
struct hlist_node *node;
|
|
struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
|
|
|
|
netlink_table_grab();
|
|
|
|
sk_for_each_bound(sk, node, &tbl->mc_list)
|
|
netlink_update_socket_mc(nlk_sk(sk), group, 0);
|
|
|
|
netlink_table_ungrab();
|
|
}
|
|
EXPORT_SYMBOL(netlink_clear_multicast_users);
|
|
|
|
void netlink_set_nonroot(int protocol, unsigned int flags)
|
|
{
|
|
if ((unsigned int)protocol < MAX_LINKS)
|
|
nl_table[protocol].nl_nonroot = flags;
|
|
}
|
|
EXPORT_SYMBOL(netlink_set_nonroot);
|
|
|
|
static void netlink_destroy_callback(struct netlink_callback *cb)
|
|
{
|
|
if (cb->skb)
|
|
kfree_skb(cb->skb);
|
|
kfree(cb);
|
|
}
|
|
|
|
/*
|
|
* It looks a bit ugly.
|
|
* It would be better to create kernel thread.
|
|
*/
|
|
|
|
static int netlink_dump(struct sock *sk)
|
|
{
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
struct netlink_callback *cb;
|
|
struct sk_buff *skb;
|
|
struct nlmsghdr *nlh;
|
|
int len, err = -ENOBUFS;
|
|
|
|
skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
|
|
if (!skb)
|
|
goto errout;
|
|
|
|
mutex_lock(nlk->cb_mutex);
|
|
|
|
cb = nlk->cb;
|
|
if (cb == NULL) {
|
|
err = -EINVAL;
|
|
goto errout_skb;
|
|
}
|
|
|
|
len = cb->dump(skb, cb);
|
|
|
|
if (len > 0) {
|
|
mutex_unlock(nlk->cb_mutex);
|
|
|
|
if (sk_filter(sk, skb))
|
|
kfree_skb(skb);
|
|
else {
|
|
skb_queue_tail(&sk->sk_receive_queue, skb);
|
|
sk->sk_data_ready(sk, skb->len);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
|
|
if (!nlh)
|
|
goto errout_skb;
|
|
|
|
memcpy(nlmsg_data(nlh), &len, sizeof(len));
|
|
|
|
if (sk_filter(sk, skb))
|
|
kfree_skb(skb);
|
|
else {
|
|
skb_queue_tail(&sk->sk_receive_queue, skb);
|
|
sk->sk_data_ready(sk, skb->len);
|
|
}
|
|
|
|
if (cb->done)
|
|
cb->done(cb);
|
|
nlk->cb = NULL;
|
|
mutex_unlock(nlk->cb_mutex);
|
|
|
|
netlink_destroy_callback(cb);
|
|
return 0;
|
|
|
|
errout_skb:
|
|
mutex_unlock(nlk->cb_mutex);
|
|
kfree_skb(skb);
|
|
errout:
|
|
return err;
|
|
}
|
|
|
|
int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
|
|
struct nlmsghdr *nlh,
|
|
int (*dump)(struct sk_buff *skb,
|
|
struct netlink_callback *),
|
|
int (*done)(struct netlink_callback *))
|
|
{
|
|
struct netlink_callback *cb;
|
|
struct sock *sk;
|
|
struct netlink_sock *nlk;
|
|
|
|
cb = kzalloc(sizeof(*cb), GFP_KERNEL);
|
|
if (cb == NULL)
|
|
return -ENOBUFS;
|
|
|
|
cb->dump = dump;
|
|
cb->done = done;
|
|
cb->nlh = nlh;
|
|
atomic_inc(&skb->users);
|
|
cb->skb = skb;
|
|
|
|
sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
|
|
if (sk == NULL) {
|
|
netlink_destroy_callback(cb);
|
|
return -ECONNREFUSED;
|
|
}
|
|
nlk = nlk_sk(sk);
|
|
/* A dump is in progress... */
|
|
mutex_lock(nlk->cb_mutex);
|
|
if (nlk->cb) {
|
|
mutex_unlock(nlk->cb_mutex);
|
|
netlink_destroy_callback(cb);
|
|
sock_put(sk);
|
|
return -EBUSY;
|
|
}
|
|
nlk->cb = cb;
|
|
mutex_unlock(nlk->cb_mutex);
|
|
|
|
netlink_dump(sk);
|
|
sock_put(sk);
|
|
|
|
/* We successfully started a dump, by returning -EINTR we
|
|
* signal not to send ACK even if it was requested.
|
|
*/
|
|
return -EINTR;
|
|
}
|
|
EXPORT_SYMBOL(netlink_dump_start);
|
|
|
|
void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
|
|
{
|
|
struct sk_buff *skb;
|
|
struct nlmsghdr *rep;
|
|
struct nlmsgerr *errmsg;
|
|
size_t payload = sizeof(*errmsg);
|
|
|
|
/* error messages get the original request appened */
|
|
if (err)
|
|
payload += nlmsg_len(nlh);
|
|
|
|
skb = nlmsg_new(payload, GFP_KERNEL);
|
|
if (!skb) {
|
|
struct sock *sk;
|
|
|
|
sk = netlink_lookup(sock_net(in_skb->sk),
|
|
in_skb->sk->sk_protocol,
|
|
NETLINK_CB(in_skb).pid);
|
|
if (sk) {
|
|
sk->sk_err = ENOBUFS;
|
|
sk->sk_error_report(sk);
|
|
sock_put(sk);
|
|
}
|
|
return;
|
|
}
|
|
|
|
rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
|
|
NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
|
|
errmsg = nlmsg_data(rep);
|
|
errmsg->error = err;
|
|
memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
|
|
netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
|
|
}
|
|
EXPORT_SYMBOL(netlink_ack);
|
|
|
|
int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
|
|
struct nlmsghdr *))
|
|
{
|
|
struct nlmsghdr *nlh;
|
|
int err;
|
|
|
|
while (skb->len >= nlmsg_total_size(0)) {
|
|
int msglen;
|
|
|
|
nlh = nlmsg_hdr(skb);
|
|
err = 0;
|
|
|
|
if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
|
|
return 0;
|
|
|
|
/* Only requests are handled by the kernel */
|
|
if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
|
|
goto ack;
|
|
|
|
/* Skip control messages */
|
|
if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
|
|
goto ack;
|
|
|
|
err = cb(skb, nlh);
|
|
if (err == -EINTR)
|
|
goto skip;
|
|
|
|
ack:
|
|
if (nlh->nlmsg_flags & NLM_F_ACK || err)
|
|
netlink_ack(skb, nlh, err);
|
|
|
|
skip:
|
|
msglen = NLMSG_ALIGN(nlh->nlmsg_len);
|
|
if (msglen > skb->len)
|
|
msglen = skb->len;
|
|
skb_pull(skb, msglen);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(netlink_rcv_skb);
|
|
|
|
/**
|
|
* nlmsg_notify - send a notification netlink message
|
|
* @sk: netlink socket to use
|
|
* @skb: notification message
|
|
* @pid: destination netlink pid for reports or 0
|
|
* @group: destination multicast group or 0
|
|
* @report: 1 to report back, 0 to disable
|
|
* @flags: allocation flags
|
|
*/
|
|
int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
|
|
unsigned int group, int report, gfp_t flags)
|
|
{
|
|
int err = 0;
|
|
|
|
if (group) {
|
|
int exclude_pid = 0;
|
|
|
|
if (report) {
|
|
atomic_inc(&skb->users);
|
|
exclude_pid = pid;
|
|
}
|
|
|
|
/* errors reported via destination sk->sk_err */
|
|
nlmsg_multicast(sk, skb, exclude_pid, group, flags);
|
|
}
|
|
|
|
if (report)
|
|
err = nlmsg_unicast(sk, skb, pid);
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL(nlmsg_notify);
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
struct nl_seq_iter {
|
|
struct seq_net_private p;
|
|
int link;
|
|
int hash_idx;
|
|
};
|
|
|
|
static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
|
|
{
|
|
struct nl_seq_iter *iter = seq->private;
|
|
int i, j;
|
|
struct sock *s;
|
|
struct hlist_node *node;
|
|
loff_t off = 0;
|
|
|
|
for (i = 0; i < MAX_LINKS; i++) {
|
|
struct nl_pid_hash *hash = &nl_table[i].hash;
|
|
|
|
for (j = 0; j <= hash->mask; j++) {
|
|
sk_for_each(s, node, &hash->table[j]) {
|
|
if (sock_net(s) != seq_file_net(seq))
|
|
continue;
|
|
if (off == pos) {
|
|
iter->link = i;
|
|
iter->hash_idx = j;
|
|
return s;
|
|
}
|
|
++off;
|
|
}
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
|
|
__acquires(nl_table_lock)
|
|
{
|
|
read_lock(&nl_table_lock);
|
|
return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
|
|
}
|
|
|
|
static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
|
|
{
|
|
struct sock *s;
|
|
struct nl_seq_iter *iter;
|
|
int i, j;
|
|
|
|
++*pos;
|
|
|
|
if (v == SEQ_START_TOKEN)
|
|
return netlink_seq_socket_idx(seq, 0);
|
|
|
|
iter = seq->private;
|
|
s = v;
|
|
do {
|
|
s = sk_next(s);
|
|
} while (s && sock_net(s) != seq_file_net(seq));
|
|
if (s)
|
|
return s;
|
|
|
|
i = iter->link;
|
|
j = iter->hash_idx + 1;
|
|
|
|
do {
|
|
struct nl_pid_hash *hash = &nl_table[i].hash;
|
|
|
|
for (; j <= hash->mask; j++) {
|
|
s = sk_head(&hash->table[j]);
|
|
while (s && sock_net(s) != seq_file_net(seq))
|
|
s = sk_next(s);
|
|
if (s) {
|
|
iter->link = i;
|
|
iter->hash_idx = j;
|
|
return s;
|
|
}
|
|
}
|
|
|
|
j = 0;
|
|
} while (++i < MAX_LINKS);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static void netlink_seq_stop(struct seq_file *seq, void *v)
|
|
__releases(nl_table_lock)
|
|
{
|
|
read_unlock(&nl_table_lock);
|
|
}
|
|
|
|
|
|
static int netlink_seq_show(struct seq_file *seq, void *v)
|
|
{
|
|
if (v == SEQ_START_TOKEN)
|
|
seq_puts(seq,
|
|
"sk Eth Pid Groups "
|
|
"Rmem Wmem Dump Locks\n");
|
|
else {
|
|
struct sock *s = v;
|
|
struct netlink_sock *nlk = nlk_sk(s);
|
|
|
|
seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
|
|
s,
|
|
s->sk_protocol,
|
|
nlk->pid,
|
|
nlk->groups ? (u32)nlk->groups[0] : 0,
|
|
atomic_read(&s->sk_rmem_alloc),
|
|
atomic_read(&s->sk_wmem_alloc),
|
|
nlk->cb,
|
|
atomic_read(&s->sk_refcnt)
|
|
);
|
|
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations netlink_seq_ops = {
|
|
.start = netlink_seq_start,
|
|
.next = netlink_seq_next,
|
|
.stop = netlink_seq_stop,
|
|
.show = netlink_seq_show,
|
|
};
|
|
|
|
|
|
static int netlink_seq_open(struct inode *inode, struct file *file)
|
|
{
|
|
return seq_open_net(inode, file, &netlink_seq_ops,
|
|
sizeof(struct nl_seq_iter));
|
|
}
|
|
|
|
static const struct file_operations netlink_seq_fops = {
|
|
.owner = THIS_MODULE,
|
|
.open = netlink_seq_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release_net,
|
|
};
|
|
|
|
#endif
|
|
|
|
int netlink_register_notifier(struct notifier_block *nb)
|
|
{
|
|
return atomic_notifier_chain_register(&netlink_chain, nb);
|
|
}
|
|
EXPORT_SYMBOL(netlink_register_notifier);
|
|
|
|
int netlink_unregister_notifier(struct notifier_block *nb)
|
|
{
|
|
return atomic_notifier_chain_unregister(&netlink_chain, nb);
|
|
}
|
|
EXPORT_SYMBOL(netlink_unregister_notifier);
|
|
|
|
static const struct proto_ops netlink_ops = {
|
|
.family = PF_NETLINK,
|
|
.owner = THIS_MODULE,
|
|
.release = netlink_release,
|
|
.bind = netlink_bind,
|
|
.connect = netlink_connect,
|
|
.socketpair = sock_no_socketpair,
|
|
.accept = sock_no_accept,
|
|
.getname = netlink_getname,
|
|
.poll = datagram_poll,
|
|
.ioctl = sock_no_ioctl,
|
|
.listen = sock_no_listen,
|
|
.shutdown = sock_no_shutdown,
|
|
.setsockopt = netlink_setsockopt,
|
|
.getsockopt = netlink_getsockopt,
|
|
.sendmsg = netlink_sendmsg,
|
|
.recvmsg = netlink_recvmsg,
|
|
.mmap = sock_no_mmap,
|
|
.sendpage = sock_no_sendpage,
|
|
};
|
|
|
|
static struct net_proto_family netlink_family_ops = {
|
|
.family = PF_NETLINK,
|
|
.create = netlink_create,
|
|
.owner = THIS_MODULE, /* for consistency 8) */
|
|
};
|
|
|
|
static int __net_init netlink_net_init(struct net *net)
|
|
{
|
|
#ifdef CONFIG_PROC_FS
|
|
if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
|
|
return -ENOMEM;
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
static void __net_exit netlink_net_exit(struct net *net)
|
|
{
|
|
#ifdef CONFIG_PROC_FS
|
|
proc_net_remove(net, "netlink");
|
|
#endif
|
|
}
|
|
|
|
static struct pernet_operations __net_initdata netlink_net_ops = {
|
|
.init = netlink_net_init,
|
|
.exit = netlink_net_exit,
|
|
};
|
|
|
|
static int __init netlink_proto_init(void)
|
|
{
|
|
struct sk_buff *dummy_skb;
|
|
int i;
|
|
unsigned long limit;
|
|
unsigned int order;
|
|
int err = proto_register(&netlink_proto, 0);
|
|
|
|
if (err != 0)
|
|
goto out;
|
|
|
|
BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
|
|
|
|
nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
|
|
if (!nl_table)
|
|
goto panic;
|
|
|
|
if (num_physpages >= (128 * 1024))
|
|
limit = num_physpages >> (21 - PAGE_SHIFT);
|
|
else
|
|
limit = num_physpages >> (23 - PAGE_SHIFT);
|
|
|
|
order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
|
|
limit = (1UL << order) / sizeof(struct hlist_head);
|
|
order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
|
|
|
|
for (i = 0; i < MAX_LINKS; i++) {
|
|
struct nl_pid_hash *hash = &nl_table[i].hash;
|
|
|
|
hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
|
|
if (!hash->table) {
|
|
while (i-- > 0)
|
|
nl_pid_hash_free(nl_table[i].hash.table,
|
|
1 * sizeof(*hash->table));
|
|
kfree(nl_table);
|
|
goto panic;
|
|
}
|
|
hash->max_shift = order;
|
|
hash->shift = 0;
|
|
hash->mask = 0;
|
|
hash->rehash_time = jiffies;
|
|
}
|
|
|
|
sock_register(&netlink_family_ops);
|
|
register_pernet_subsys(&netlink_net_ops);
|
|
/* The netlink device handler may be needed early. */
|
|
rtnetlink_init();
|
|
out:
|
|
return err;
|
|
panic:
|
|
panic("netlink_init: Cannot allocate nl_table\n");
|
|
}
|
|
|
|
core_initcall(netlink_proto_init);
|