![Martin Murray](/assets/img/avatar_default.png)
From: Martin Murray <murrayma@citi.umich.edu> Sanity check nlmsg_len during netlink_rcv_skb. An nlmsg_len == 0 can cause infinite loop in kernel, effectively DoSing machine. Noted by Matin Murray. Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: David S. Miller <davem@davemloft.net>
1762 lines
39 KiB
C
1762 lines
39 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/config.h>
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#include <linux/module.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/smp_lock.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 <net/sock.h>
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#include <net/scm.h>
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#include <net/netlink.h>
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#define Nprintk(a...)
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#define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
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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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spinlock_t cb_lock;
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void (*data_ready)(struct sock *sk, int bytes);
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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 (struct netlink_sock *)sk;
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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 int nl_nonroot;
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unsigned int groups;
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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 struct notifier_block *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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skb_queue_purge(&sk->sk_receive_queue);
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if (!sock_flag(sk, SOCK_DEAD)) {
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printk("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)->cb);
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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 SMP.
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* 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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{
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write_lock_bh(&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_bh(&nl_table_lock);
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schedule();
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write_lock_bh(&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 __inline__ void netlink_table_ungrab(void)
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{
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write_unlock_bh(&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(int protocol, 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 (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_alloc(size_t size)
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{
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if (size <= PAGE_SIZE)
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return kmalloc(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, 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_alloc(size);
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if (!table)
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return 0;
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memset(table, 0, size);
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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 int netlink_insert(struct sock *sk, 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 (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 socket *sock, 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(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
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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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spin_lock_init(&nlk->cb_lock);
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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 socket *sock, int protocol)
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{
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struct module *module = NULL;
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struct netlink_sock *nlk;
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unsigned int groups;
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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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groups = nl_table[protocol].groups;
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netlink_unlock_table();
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if ((err = __netlink_create(sock, protocol)) < 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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nlk = nlk_sk(sk);
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spin_lock(&nlk->cb_lock);
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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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nlk->cb = NULL;
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}
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spin_unlock(&nlk->cb_lock);
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/* OK. Socket is unlinked, and, therefore,
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no new packets will arrive */
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sock_orphan(sk);
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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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|
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if (nlk->pid && !nlk->subscriptions) {
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struct netlink_notify n = {
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.protocol = sk->sk_protocol,
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.pid = nlk->pid,
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};
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notifier_call_chain(&netlink_chain, NETLINK_URELEASE, &n);
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}
|
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|
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if (nlk->module)
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module_put(nlk->module);
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|
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if (nlk->flags & NETLINK_KERNEL_SOCKET) {
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netlink_table_grab();
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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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netlink_table_ungrab();
|
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}
|
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|
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kfree(nlk->groups);
|
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nlk->groups = NULL;
|
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|
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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 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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|
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retry:
|
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cond_resched();
|
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netlink_table_grab();
|
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head = nl_pid_hashfn(hash, pid);
|
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sk_for_each(osk, node, head) {
|
|
if (nlk_sk(osk)->pid == pid) {
|
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/* Bind collision, search negative pid values. */
|
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pid = rover--;
|
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if (rover > -4097)
|
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rover = -4097;
|
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netlink_table_ungrab();
|
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goto retry;
|
|
}
|
|
}
|
|
netlink_table_ungrab();
|
|
|
|
err = netlink_insert(sk, pid);
|
|
if (err == -EADDRINUSE)
|
|
goto retry;
|
|
|
|
/* If 2 threads race to autobind, that is fine. */
|
|
if (err == -EBUSY)
|
|
err = 0;
|
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|
|
return err;
|
|
}
|
|
|
|
static inline int netlink_capable(struct socket *sock, unsigned int flag)
|
|
{
|
|
return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
|
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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_alloc_groups(struct sock *sk)
|
|
{
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
unsigned int groups;
|
|
int err = 0;
|
|
|
|
netlink_lock_table();
|
|
groups = nl_table[sk->sk_protocol].groups;
|
|
if (!nl_table[sk->sk_protocol].registered)
|
|
err = -ENOENT;
|
|
netlink_unlock_table();
|
|
|
|
if (err)
|
|
return err;
|
|
|
|
nlk->groups = kmalloc(NLGRPSZ(groups), GFP_KERNEL);
|
|
if (nlk->groups == NULL)
|
|
return -ENOMEM;
|
|
memset(nlk->groups, 0, NLGRPSZ(groups));
|
|
nlk->ngroups = groups;
|
|
return 0;
|
|
}
|
|
|
|
static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
|
|
{
|
|
struct sock *sk = sock->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;
|
|
if (nlk->groups == NULL) {
|
|
err = netlink_alloc_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, 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_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)
|
|
{
|
|
int protocol = ssk->sk_protocol;
|
|
struct sock *sock;
|
|
struct netlink_sock *nlk;
|
|
|
|
sock = netlink_lookup(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 ((nlk->pid == 0 && !nlk->data_ready) ||
|
|
(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_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 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 (!nlk->pid)
|
|
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 protocol)
|
|
{
|
|
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;
|
|
}
|
|
|
|
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);
|
|
}
|
|
err = netlink_attachskb(sk, skb, nonblock, timeo);
|
|
if (err == 1)
|
|
goto retry;
|
|
if (err)
|
|
return err;
|
|
|
|
return netlink_sendskb(sk, skb, ssk->sk_protocol);
|
|
}
|
|
|
|
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;
|
|
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 (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 ((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 netlink_broadcast_data info;
|
|
struct hlist_node *node;
|
|
struct sock *sk;
|
|
|
|
skb = netlink_trim(skb, allocation);
|
|
|
|
info.exclude_sk = ssk;
|
|
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;
|
|
}
|
|
|
|
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 (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);
|
|
}
|
|
|
|
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);
|
|
int val = 0, err;
|
|
|
|
if (level != SOL_NETLINK)
|
|
return -ENOPROTOOPT;
|
|
|
|
if (optlen >= sizeof(int) &&
|
|
get_user(val, (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: {
|
|
unsigned int subscriptions;
|
|
int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0;
|
|
|
|
if (!netlink_capable(sock, NL_NONROOT_RECV))
|
|
return -EPERM;
|
|
if (nlk->groups == NULL) {
|
|
err = netlink_alloc_groups(sk);
|
|
if (err)
|
|
return err;
|
|
}
|
|
if (!val || val - 1 >= nlk->ngroups)
|
|
return -EINVAL;
|
|
netlink_table_grab();
|
|
old = test_bit(val - 1, nlk->groups);
|
|
subscriptions = nlk->subscriptions - old + new;
|
|
if (new)
|
|
__set_bit(val - 1, nlk->groups);
|
|
else
|
|
__clear_bit(val - 1, nlk->groups);
|
|
netlink_update_subscriptions(sk, subscriptions);
|
|
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;
|
|
put_user(len, optlen);
|
|
put_user(val, optval);
|
|
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 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 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_pid = dst_pid;
|
|
NETLINK_CB(skb).dst_group = dst_group;
|
|
NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context);
|
|
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->h.raw = skb->data;
|
|
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 (NULL == siocb->scm) {
|
|
memset(&scm, 0, sizeof(scm));
|
|
siocb->scm = &scm;
|
|
}
|
|
siocb->scm->creds = *NETLINK_CREDS(skb);
|
|
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);
|
|
if (nlk->flags & NETLINK_RECV_PKTINFO)
|
|
netlink_cmsg_recv_pktinfo(msg, skb);
|
|
|
|
out:
|
|
netlink_rcv_wake(sk);
|
|
return err ? : copied;
|
|
}
|
|
|
|
static void netlink_data_ready(struct sock *sk, int len)
|
|
{
|
|
struct netlink_sock *nlk = nlk_sk(sk);
|
|
|
|
if (nlk->data_ready)
|
|
nlk->data_ready(sk, len);
|
|
netlink_rcv_wake(sk);
|
|
}
|
|
|
|
/*
|
|
* 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(int unit, unsigned int groups,
|
|
void (*input)(struct sock *sk, int len),
|
|
struct module *module)
|
|
{
|
|
struct socket *sock;
|
|
struct sock *sk;
|
|
struct netlink_sock *nlk;
|
|
|
|
if (!nl_table)
|
|
return NULL;
|
|
|
|
if (unit<0 || unit>=MAX_LINKS)
|
|
return NULL;
|
|
|
|
if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
|
|
return NULL;
|
|
|
|
if (__netlink_create(sock, unit) < 0)
|
|
goto out_sock_release;
|
|
|
|
sk = sock->sk;
|
|
sk->sk_data_ready = netlink_data_ready;
|
|
if (input)
|
|
nlk_sk(sk)->data_ready = input;
|
|
|
|
if (netlink_insert(sk, 0))
|
|
goto out_sock_release;
|
|
|
|
nlk = nlk_sk(sk);
|
|
nlk->flags |= NETLINK_KERNEL_SOCKET;
|
|
|
|
netlink_table_grab();
|
|
nl_table[unit].groups = groups < 32 ? 32 : groups;
|
|
nl_table[unit].module = module;
|
|
nl_table[unit].registered = 1;
|
|
netlink_table_ungrab();
|
|
|
|
return sk;
|
|
|
|
out_sock_release:
|
|
sock_release(sock);
|
|
return NULL;
|
|
}
|
|
|
|
void netlink_set_nonroot(int protocol, unsigned int flags)
|
|
{
|
|
if ((unsigned int)protocol < MAX_LINKS)
|
|
nl_table[protocol].nl_nonroot = flags;
|
|
}
|
|
|
|
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;
|
|
|
|
skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
|
|
if (!skb)
|
|
return -ENOBUFS;
|
|
|
|
spin_lock(&nlk->cb_lock);
|
|
|
|
cb = nlk->cb;
|
|
if (cb == NULL) {
|
|
spin_unlock(&nlk->cb_lock);
|
|
kfree_skb(skb);
|
|
return -EINVAL;
|
|
}
|
|
|
|
len = cb->dump(skb, cb);
|
|
|
|
if (len > 0) {
|
|
spin_unlock(&nlk->cb_lock);
|
|
skb_queue_tail(&sk->sk_receive_queue, skb);
|
|
sk->sk_data_ready(sk, len);
|
|
return 0;
|
|
}
|
|
|
|
nlh = NLMSG_NEW_ANSWER(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
|
|
memcpy(NLMSG_DATA(nlh), &len, sizeof(len));
|
|
skb_queue_tail(&sk->sk_receive_queue, skb);
|
|
sk->sk_data_ready(sk, skb->len);
|
|
|
|
if (cb->done)
|
|
cb->done(cb);
|
|
nlk->cb = NULL;
|
|
spin_unlock(&nlk->cb_lock);
|
|
|
|
netlink_destroy_callback(cb);
|
|
return 0;
|
|
|
|
nlmsg_failure:
|
|
return -ENOBUFS;
|
|
}
|
|
|
|
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 = kmalloc(sizeof(*cb), GFP_KERNEL);
|
|
if (cb == NULL)
|
|
return -ENOBUFS;
|
|
|
|
memset(cb, 0, sizeof(*cb));
|
|
cb->dump = dump;
|
|
cb->done = done;
|
|
cb->nlh = nlh;
|
|
atomic_inc(&skb->users);
|
|
cb->skb = skb;
|
|
|
|
sk = netlink_lookup(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... */
|
|
spin_lock(&nlk->cb_lock);
|
|
if (nlk->cb) {
|
|
spin_unlock(&nlk->cb_lock);
|
|
netlink_destroy_callback(cb);
|
|
sock_put(sk);
|
|
return -EBUSY;
|
|
}
|
|
nlk->cb = cb;
|
|
spin_unlock(&nlk->cb_lock);
|
|
|
|
netlink_dump(sk);
|
|
sock_put(sk);
|
|
return 0;
|
|
}
|
|
|
|
void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
|
|
{
|
|
struct sk_buff *skb;
|
|
struct nlmsghdr *rep;
|
|
struct nlmsgerr *errmsg;
|
|
int size;
|
|
|
|
if (err == 0)
|
|
size = NLMSG_SPACE(sizeof(struct nlmsgerr));
|
|
else
|
|
size = NLMSG_SPACE(4 + NLMSG_ALIGN(nlh->nlmsg_len));
|
|
|
|
skb = alloc_skb(size, GFP_KERNEL);
|
|
if (!skb) {
|
|
struct sock *sk;
|
|
|
|
sk = netlink_lookup(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(struct nlmsghdr));
|
|
netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
|
|
}
|
|
|
|
static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
|
|
struct nlmsghdr *, int *))
|
|
{
|
|
unsigned int total_len;
|
|
struct nlmsghdr *nlh;
|
|
int err;
|
|
|
|
while (skb->len >= nlmsg_total_size(0)) {
|
|
nlh = (struct nlmsghdr *) skb->data;
|
|
|
|
if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
|
|
return 0;
|
|
|
|
total_len = min(NLMSG_ALIGN(nlh->nlmsg_len), skb->len);
|
|
|
|
if (cb(skb, nlh, &err) < 0) {
|
|
/* Not an error, but we have to interrupt processing
|
|
* here. Note: that in this case we do not pull
|
|
* message from skb, it will be processed later.
|
|
*/
|
|
if (err == 0)
|
|
return -1;
|
|
netlink_ack(skb, nlh, err);
|
|
} else if (nlh->nlmsg_flags & NLM_F_ACK)
|
|
netlink_ack(skb, nlh, 0);
|
|
|
|
skb_pull(skb, total_len);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* nelink_run_queue - Process netlink receive queue.
|
|
* @sk: Netlink socket containing the queue
|
|
* @qlen: Place to store queue length upon entry
|
|
* @cb: Callback function invoked for each netlink message found
|
|
*
|
|
* Processes as much as there was in the queue upon entry and invokes
|
|
* a callback function for each netlink message found. The callback
|
|
* function may refuse a message by returning a negative error code
|
|
* but setting the error pointer to 0 in which case this function
|
|
* returns with a qlen != 0.
|
|
*
|
|
* qlen must be initialized to 0 before the initial entry, afterwards
|
|
* the function may be called repeatedly until qlen reaches 0.
|
|
*/
|
|
void netlink_run_queue(struct sock *sk, unsigned int *qlen,
|
|
int (*cb)(struct sk_buff *, struct nlmsghdr *, int *))
|
|
{
|
|
struct sk_buff *skb;
|
|
|
|
if (!*qlen || *qlen > skb_queue_len(&sk->sk_receive_queue))
|
|
*qlen = skb_queue_len(&sk->sk_receive_queue);
|
|
|
|
for (; *qlen; (*qlen)--) {
|
|
skb = skb_dequeue(&sk->sk_receive_queue);
|
|
if (netlink_rcv_skb(skb, cb)) {
|
|
if (skb->len)
|
|
skb_queue_head(&sk->sk_receive_queue, skb);
|
|
else {
|
|
kfree_skb(skb);
|
|
(*qlen)--;
|
|
}
|
|
break;
|
|
}
|
|
|
|
kfree_skb(skb);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* netlink_queue_skip - Skip netlink message while processing queue.
|
|
* @nlh: Netlink message to be skipped
|
|
* @skb: Socket buffer containing the netlink messages.
|
|
*
|
|
* Pulls the given netlink message off the socket buffer so the next
|
|
* call to netlink_queue_run() will not reconsider the message.
|
|
*/
|
|
void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb)
|
|
{
|
|
int msglen = NLMSG_ALIGN(nlh->nlmsg_len);
|
|
|
|
if (msglen > skb->len)
|
|
msglen = skb->len;
|
|
|
|
skb_pull(skb, msglen);
|
|
}
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
struct nl_seq_iter {
|
|
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 (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)
|
|
{
|
|
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);
|
|
|
|
s = sk_next(v);
|
|
if (s)
|
|
return s;
|
|
|
|
iter = seq->private;
|
|
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]);
|
|
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)
|
|
{
|
|
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 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)
|
|
{
|
|
struct seq_file *seq;
|
|
struct nl_seq_iter *iter;
|
|
int err;
|
|
|
|
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
|
|
if (!iter)
|
|
return -ENOMEM;
|
|
|
|
err = seq_open(file, &netlink_seq_ops);
|
|
if (err) {
|
|
kfree(iter);
|
|
return err;
|
|
}
|
|
|
|
memset(iter, 0, sizeof(*iter));
|
|
seq = file->private_data;
|
|
seq->private = iter;
|
|
return 0;
|
|
}
|
|
|
|
static struct file_operations netlink_seq_fops = {
|
|
.owner = THIS_MODULE,
|
|
.open = netlink_seq_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release_private,
|
|
};
|
|
|
|
#endif
|
|
|
|
int netlink_register_notifier(struct notifier_block *nb)
|
|
{
|
|
return notifier_chain_register(&netlink_chain, nb);
|
|
}
|
|
|
|
int netlink_unregister_notifier(struct notifier_block *nb)
|
|
{
|
|
return notifier_chain_unregister(&netlink_chain, nb);
|
|
}
|
|
|
|
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) */
|
|
};
|
|
|
|
extern void netlink_skb_parms_too_large(void);
|
|
|
|
static int __init netlink_proto_init(void)
|
|
{
|
|
struct sk_buff *dummy_skb;
|
|
int i;
|
|
unsigned long max;
|
|
unsigned int order;
|
|
int err = proto_register(&netlink_proto, 0);
|
|
|
|
if (err != 0)
|
|
goto out;
|
|
|
|
if (sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb))
|
|
netlink_skb_parms_too_large();
|
|
|
|
nl_table = kmalloc(sizeof(*nl_table) * MAX_LINKS, GFP_KERNEL);
|
|
if (!nl_table) {
|
|
enomem:
|
|
printk(KERN_CRIT "netlink_init: Cannot allocate nl_table\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
memset(nl_table, 0, sizeof(*nl_table) * MAX_LINKS);
|
|
|
|
if (num_physpages >= (128 * 1024))
|
|
max = num_physpages >> (21 - PAGE_SHIFT);
|
|
else
|
|
max = num_physpages >> (23 - PAGE_SHIFT);
|
|
|
|
order = get_bitmask_order(max) - 1 + PAGE_SHIFT;
|
|
max = (1UL << order) / sizeof(struct hlist_head);
|
|
order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1;
|
|
|
|
for (i = 0; i < MAX_LINKS; i++) {
|
|
struct nl_pid_hash *hash = &nl_table[i].hash;
|
|
|
|
hash->table = nl_pid_hash_alloc(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 enomem;
|
|
}
|
|
memset(hash->table, 0, 1 * sizeof(*hash->table));
|
|
hash->max_shift = order;
|
|
hash->shift = 0;
|
|
hash->mask = 0;
|
|
hash->rehash_time = jiffies;
|
|
}
|
|
|
|
sock_register(&netlink_family_ops);
|
|
#ifdef CONFIG_PROC_FS
|
|
proc_net_fops_create("netlink", 0, &netlink_seq_fops);
|
|
#endif
|
|
/* The netlink device handler may be needed early. */
|
|
rtnetlink_init();
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
core_initcall(netlink_proto_init);
|
|
|
|
EXPORT_SYMBOL(netlink_ack);
|
|
EXPORT_SYMBOL(netlink_run_queue);
|
|
EXPORT_SYMBOL(netlink_queue_skip);
|
|
EXPORT_SYMBOL(netlink_broadcast);
|
|
EXPORT_SYMBOL(netlink_dump_start);
|
|
EXPORT_SYMBOL(netlink_kernel_create);
|
|
EXPORT_SYMBOL(netlink_register_notifier);
|
|
EXPORT_SYMBOL(netlink_set_err);
|
|
EXPORT_SYMBOL(netlink_set_nonroot);
|
|
EXPORT_SYMBOL(netlink_unicast);
|
|
EXPORT_SYMBOL(netlink_unregister_notifier);
|
|
|