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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/net/netlink/af_netlink.c

1762 строки
38 KiB
C
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/*
* NETLINK Kernel-user communication protocol.
*
* Authors: Alan Cox <alan@redhat.com>
* Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
* added netlink_proto_exit
* Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
* use nlk_sk, as sk->protinfo is on a diet 8)
* Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
* - inc module use count of module that owns
* the kernel socket in case userspace opens
* socket of same protocol
* - remove all module support, since netlink is
* mandatory if CONFIG_NET=y these days
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/socket.h>
#include <linux/un.h>
#include <linux/fcntl.h>
#include <linux/termios.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/smp_lock.h>
#include <linux/notifier.h>
#include <linux/security.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/random.h>
#include <linux/bitops.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/audit.h>
#include <net/sock.h>
#include <net/scm.h>
#include <net/netlink.h>
#define Nprintk(a...)
#define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
struct netlink_sock {
/* struct sock has to be the first member of netlink_sock */
struct sock sk;
u32 pid;
u32 dst_pid;
u32 dst_group;
u32 flags;
u32 subscriptions;
u32 ngroups;
unsigned long *groups;
unsigned long state;
wait_queue_head_t wait;
struct netlink_callback *cb;
spinlock_t cb_lock;
void (*data_ready)(struct sock *sk, int bytes);
struct module *module;
};
#define NETLINK_KERNEL_SOCKET 0x1
#define NETLINK_RECV_PKTINFO 0x2
static inline struct netlink_sock *nlk_sk(struct sock *sk)
{
return (struct netlink_sock *)sk;
}
struct nl_pid_hash {
struct hlist_head *table;
unsigned long rehash_time;
unsigned int mask;
unsigned int shift;
unsigned int entries;
unsigned int max_shift;
u32 rnd;
};
struct netlink_table {
struct nl_pid_hash hash;
struct hlist_head mc_list;
unsigned int nl_nonroot;
unsigned int groups;
struct module *module;
int registered;
};
static struct netlink_table *nl_table;
static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
static int netlink_dump(struct sock *sk);
static void netlink_destroy_callback(struct netlink_callback *cb);
static DEFINE_RWLOCK(nl_table_lock);
static atomic_t nl_table_users = ATOMIC_INIT(0);
static struct notifier_block *netlink_chain;
static u32 netlink_group_mask(u32 group)
{
return group ? 1 << (group - 1) : 0;
}
static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
{
return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
}
static void netlink_sock_destruct(struct sock *sk)
{
skb_queue_purge(&sk->sk_receive_queue);
if (!sock_flag(sk, SOCK_DEAD)) {
printk("Freeing alive netlink socket %p\n", sk);
return;
}
BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
BUG_TRAP(!nlk_sk(sk)->cb);
BUG_TRAP(!nlk_sk(sk)->groups);
}
/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP.
* Look, when several writers sleep and reader wakes them up, all but one
* immediately hit write lock and grab all the cpus. Exclusive sleep solves
* this, _but_ remember, it adds useless work on UP machines.
*/
static void netlink_table_grab(void)
{
write_lock_bh(&nl_table_lock);
if (atomic_read(&nl_table_users)) {
DECLARE_WAITQUEUE(wait, current);
add_wait_queue_exclusive(&nl_table_wait, &wait);
for(;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (atomic_read(&nl_table_users) == 0)
break;
write_unlock_bh(&nl_table_lock);
schedule();
write_lock_bh(&nl_table_lock);
}
__set_current_state(TASK_RUNNING);
remove_wait_queue(&nl_table_wait, &wait);
}
}
static __inline__ void netlink_table_ungrab(void)
{
write_unlock_bh(&nl_table_lock);
wake_up(&nl_table_wait);
}
static __inline__ void
netlink_lock_table(void)
{
/* read_lock() synchronizes us to netlink_table_grab */
read_lock(&nl_table_lock);
atomic_inc(&nl_table_users);
read_unlock(&nl_table_lock);
}
static __inline__ void
netlink_unlock_table(void)
{
if (atomic_dec_and_test(&nl_table_users))
wake_up(&nl_table_wait);
}
static __inline__ struct sock *netlink_lookup(int protocol, u32 pid)
{
struct nl_pid_hash *hash = &nl_table[protocol].hash;
struct hlist_head *head;
struct sock *sk;
struct hlist_node *node;
read_lock(&nl_table_lock);
head = nl_pid_hashfn(hash, pid);
sk_for_each(sk, node, head) {
if (nlk_sk(sk)->pid == pid) {
sock_hold(sk);
goto found;
}
}
sk = NULL;
found:
read_unlock(&nl_table_lock);
return sk;
}
static inline struct hlist_head *nl_pid_hash_alloc(size_t size)
{
if (size <= PAGE_SIZE)
return kmalloc(size, GFP_ATOMIC);
else
return (struct hlist_head *)
__get_free_pages(GFP_ATOMIC, get_order(size));
}
static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
{
if (size <= PAGE_SIZE)
kfree(table);
else
free_pages((unsigned long)table, get_order(size));
}
static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
{
unsigned int omask, mask, shift;
size_t osize, size;
struct hlist_head *otable, *table;
int i;
omask = mask = hash->mask;
osize = size = (mask + 1) * sizeof(*table);
shift = hash->shift;
if (grow) {
if (++shift > hash->max_shift)
return 0;
mask = mask * 2 + 1;
size *= 2;
}
table = nl_pid_hash_alloc(size);
if (!table)
return 0;
memset(table, 0, size);
otable = hash->table;
hash->table = table;
hash->mask = mask;
hash->shift = shift;
get_random_bytes(&hash->rnd, sizeof(hash->rnd));
for (i = 0; i <= omask; i++) {
struct sock *sk;
struct hlist_node *node, *tmp;
sk_for_each_safe(sk, node, tmp, &otable[i])
__sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
}
nl_pid_hash_free(otable, osize);
hash->rehash_time = jiffies + 10 * 60 * HZ;
return 1;
}
static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
{
int avg = hash->entries >> hash->shift;
if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
return 1;
if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
nl_pid_hash_rehash(hash, 0);
return 1;
}
return 0;
}
static struct proto_ops netlink_ops;
static int netlink_insert(struct sock *sk, u32 pid)
{
struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
struct hlist_head *head;
int err = -EADDRINUSE;
struct sock *osk;
struct hlist_node *node;
int len;
netlink_table_grab();
head = nl_pid_hashfn(hash, pid);
len = 0;
sk_for_each(osk, node, head) {
if (nlk_sk(osk)->pid == pid)
break;
len++;
}
if (node)
goto err;
err = -EBUSY;
if (nlk_sk(sk)->pid)
goto err;
err = -ENOMEM;
if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
goto err;
if (len && nl_pid_hash_dilute(hash, len))
head = nl_pid_hashfn(hash, pid);
hash->entries++;
nlk_sk(sk)->pid = pid;
sk_add_node(sk, head);
err = 0;
err:
netlink_table_ungrab();
return err;
}
static void netlink_remove(struct sock *sk)
{
netlink_table_grab();
if (sk_del_node_init(sk))
nl_table[sk->sk_protocol].hash.entries--;
if (nlk_sk(sk)->subscriptions)
__sk_del_bind_node(sk);
netlink_table_ungrab();
}
static struct proto netlink_proto = {
.name = "NETLINK",
.owner = THIS_MODULE,
.obj_size = sizeof(struct netlink_sock),
};
static int __netlink_create(struct socket *sock, int protocol)
{
struct sock *sk;
struct netlink_sock *nlk;
sock->ops = &netlink_ops;
sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
if (!sk)
return -ENOMEM;
sock_init_data(sock, sk);
nlk = nlk_sk(sk);
spin_lock_init(&nlk->cb_lock);
init_waitqueue_head(&nlk->wait);
sk->sk_destruct = netlink_sock_destruct;
sk->sk_protocol = protocol;
return 0;
}
static int netlink_create(struct socket *sock, int protocol)
{
struct module *module = NULL;
struct netlink_sock *nlk;
unsigned int groups;
int err = 0;
sock->state = SS_UNCONNECTED;
if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
return -ESOCKTNOSUPPORT;
if (protocol<0 || protocol >= MAX_LINKS)
return -EPROTONOSUPPORT;
netlink_lock_table();
#ifdef CONFIG_KMOD
if (!nl_table[protocol].registered) {
netlink_unlock_table();
request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
netlink_lock_table();
}
#endif
if (nl_table[protocol].registered &&
try_module_get(nl_table[protocol].module))
module = nl_table[protocol].module;
groups = nl_table[protocol].groups;
netlink_unlock_table();
if ((err = __netlink_create(sock, protocol) < 0))
goto out_module;
nlk = nlk_sk(sock->sk);
nlk->module = module;
out:
return err;
out_module:
module_put(module);
goto out;
}
static int netlink_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk;
if (!sk)
return 0;
netlink_remove(sk);
nlk = nlk_sk(sk);
spin_lock(&nlk->cb_lock);
if (nlk->cb) {
if (nlk->cb->done)
nlk->cb->done(nlk->cb);
netlink_destroy_callback(nlk->cb);
nlk->cb = NULL;
}
spin_unlock(&nlk->cb_lock);
/* OK. Socket is unlinked, and, therefore,
no new packets will arrive */
sock_orphan(sk);
sock->sk = NULL;
wake_up_interruptible_all(&nlk->wait);
skb_queue_purge(&sk->sk_write_queue);
if (nlk->pid && !nlk->subscriptions) {
struct netlink_notify n = {
.protocol = sk->sk_protocol,
.pid = nlk->pid,
};
notifier_call_chain(&netlink_chain, NETLINK_URELEASE, &n);
}
if (nlk->module)
module_put(nlk->module);
if (nlk->flags & NETLINK_KERNEL_SOCKET) {
netlink_table_grab();
nl_table[sk->sk_protocol].module = NULL;
nl_table[sk->sk_protocol].registered = 0;
netlink_table_ungrab();
}
kfree(nlk->groups);
nlk->groups = NULL;
sock_put(sk);
return 0;
}
static int netlink_autobind(struct socket *sock)
{
struct sock *sk = sock->sk;
struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
struct hlist_head *head;
struct sock *osk;
struct hlist_node *node;
s32 pid = current->tgid;
int err;
static s32 rover = -4097;
retry:
cond_resched();
netlink_table_grab();
head = nl_pid_hashfn(hash, pid);
sk_for_each(osk, node, head) {
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, 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_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 (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 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);
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