/*
* 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)
*
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/major.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 <net/sock.h>
#include <net/scm.h>
#define Nprintk(a...)
#if defined(CONFIG_NETLINK_DEV) || defined(CONFIG_NETLINK_DEV_MODULE)
#define NL_EMULATE_DEV
#endif
struct netlink_opt
{
u32 pid;
unsigned groups;
u32 dst_pid;
unsigned dst_groups;
unsigned long state;
int (*handler)(int unit, struct sk_buff *skb);
wait_queue_head_t wait;
struct netlink_callback *cb;
spinlock_t cb_lock;
void (*data_ready)(struct sock *sk, int bytes);
};
#define nlk_sk(__sk) ((struct netlink_opt *)(__sk)->sk_protinfo)
static struct hlist_head nl_table[MAX_LINKS];
static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
static unsigned nl_nonroot[MAX_LINKS];
#ifdef NL_EMULATE_DEV
static struct socket *netlink_kernel[MAX_LINKS];
#endif
static int netlink_dump(struct sock *sk);
static void netlink_destroy_callback(struct netlink_callback *cb);
atomic_t netlink_sock_nr;
static rwlock_t nl_table_lock = RW_LOCK_UNLOCKED;
static atomic_t nl_table_users = ATOMIC_INIT(0);
static struct notifier_block *netlink_chain;
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);
kfree(nlk_sk(sk));
atomic_dec(&netlink_sock_nr);
#ifdef NETLINK_REFCNT_DEBUG
printk(KERN_DEBUG "NETLINK %p released, %d are still alive\n", sk, atomic_read(&netlink_sock_nr));
#endif
}
/* 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 sock *sk;
struct hlist_node *node;
read_lock(&nl_table_lock);
sk_for_each(sk, node, &nl_table[protocol]) {
if (nlk_sk(sk)->pid == pid) {
sock_hold(sk);
goto found;
}
}
sk = NULL;
found:
read_unlock(&nl_table_lock);
return sk;
}
extern struct proto_ops netlink_ops;
static int netlink_insert(struct sock *sk, u32 pid)
{
int err = -EADDRINUSE;
struct sock *osk;
struct hlist_node *node;
netlink_table_grab();
sk_for_each(osk, node, &nl_table[sk->sk_protocol]) {
if (nlk_sk(osk)->pid == pid)
break;
}
if (!node) {
err = -EBUSY;
if (nlk_sk(sk)->pid == 0) {
nlk_sk(sk)->pid = pid;
sk_add_node(sk, &nl_table[sk->sk_protocol]);
err = 0;
}
}
netlink_table_ungrab();
return err;
}
static void netlink_remove(struct sock *sk)
{
netlink_table_grab();
sk_del_node_init(sk);
netlink_table_ungrab();
}
static int netlink_create(struct socket *sock, int protocol)
{
struct sock *sk;
struct netlink_opt *nlk;
sock->state = SS_UNCONNECTED;
if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
return -ESOCKTNOSUPPORT;
if (protocol<0 || protocol >= MAX_LINKS)
return -EPROTONOSUPPORT;
sock->ops = &netlink_ops;
sk = sk_alloc(PF_NETLINK, GFP_KERNEL, 1, NULL);
if (!sk)
return -ENOMEM;
sock_init_data(sock,sk);
sk_set_owner(sk, THIS_MODULE);
nlk = nlk_sk(sk) = kmalloc(sizeof(*nlk), GFP_KERNEL);
if (!nlk) {
sk_free(sk);
return -ENOMEM;
}
memset(nlk, 0, sizeof(*nlk));
spin_lock_init(&nlk->cb_lock);
init_waitqueue_head(&nlk->wait);
sk->sk_destruct = netlink_sock_destruct;
atomic_inc(&netlink_sock_nr);
sk->sk_protocol = protocol;
return 0;
}
static int netlink_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct netlink_opt *nlk;
if (!sk)
return 0;
netlink_remove(sk);
nlk = nlk_sk(sk);
spin_lock(&nlk->cb_lock);
if (nlk->cb) {
nlk->cb->done(nlk->cb);
netlink_destroy_callback(nlk->cb);
nlk->cb = NULL;
__sock_put(sk);
}
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->groups) {
struct netlink_notify n = {
.protocol = sk->sk_protocol,
.pid = nlk->pid,
};
notifier_call_chain(&netlink_chain, NETLINK_URELEASE, &n);
}
sock_put(sk);
return 0;
}
static int netlink_autobind(struct socket *sock)
{
struct sock *sk = sock->sk;
struct sock *osk;
struct hlist_node *node;
s32 pid = current->pid;
int err;
retry:
netlink_table_grab();
sk_for_each(osk, node, &nl_table[sk->sk_protocol]) {
if (nlk_sk(osk)->pid == pid) {
/* Bind collision, search negative pid values. */
if (pid > 0)
pid = -4096;
pid--;
netlink_table_ungrab();
goto retry;
}
}
netlink_table_ungrab();
err = netlink_insert(sk, pid);
if (err == -EADDRINUSE)
goto retry;
nlk_sk(sk)->groups = 0;
return 0;
}
static inline int netlink_capable(struct socket *sock, unsigned flag)
{
return (nl_nonroot[sock->sk->sk_protocol] & flag) ||
capable(CAP_NET_ADMIN);
}
static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
{
struct sock *sk = sock->sk;
struct netlink_opt *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 && !netlink_capable(sock, NL_NONROOT_RECV))
return -EPERM;
if (nlk->pid) {
if (nladdr->nl_pid != nlk->pid)
return -EINVAL;
nlk->groups = nladdr->nl_groups;
return 0;
}
if (nladdr->nl_pid == 0) {
err = netlink_autobind(sock);
if (err == 0)
nlk->groups = nladdr->nl_groups;
return err;
}
err = netlink_insert(sk, nladdr->nl_pid);
if (err == 0)
nlk->groups = nladdr->nl_groups;
return err;
}
static int netlink_connect(struct socket *sock, struct sockaddr *addr,
int alen, int flags)
{
int err = 0;
struct sock *sk = sock->sk;
struct netlink_opt *nlk = nlk_sk(sk);
struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr;
if (addr->sa_family == AF_UNSPEC) {
nlk->dst_pid = 0;
nlk->dst_groups = 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) {
nlk->dst_pid = nladdr->nl_pid;
nlk->dst_groups = nladdr->nl_groups;
}
return 0;
}
static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer)
{
struct sock *sk = sock->sk;
struct netlink_opt *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 = nlk->dst_groups;
} else {
nladdr->nl_pid = nlk->pid;
nladdr->nl_groups = nlk->groups;
}
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);
}
}
int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock)
{
struct sock *sk;
struct netlink_opt *nlk;
int len = skb->len;
int protocol = ssk->sk_protocol;
long timeo;
DECLARE_WAITQUEUE(wait, current);
timeo = sock_sndtimeo(ssk, nonblock);
retry:
sk = netlink_lookup(protocol, pid);
if (sk == NULL)
goto no_dst;
nlk = nlk_sk(sk);
/* Don't bother queuing skb if kernel socket has no input function */
if (nlk->pid == 0 && !nlk->data_ready)
goto no_dst;
#ifdef NL_EMULATE_DEV
if (nlk->handler) {
skb_orphan(skb);
len = nlk->handler(protocol, skb);
sock_put(sk);
return len;
}
#endif
if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
test_bit(0, &nlk->state)) {
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);
}
goto retry;
}
skb_orphan(skb);
skb_set_owner_r(skb, sk);
skb_queue_tail(&sk->sk_receive_queue, skb);
sk->sk_data_ready(sk, len);
sock_put(sk);
return len;
no_dst:
kfree_skb(skb);
return -ECONNREFUSED;
}
static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
{
struct netlink_opt *nlk = nlk_sk(sk);
#ifdef NL_EMULATE_DEV
if (nlk->handler) {
skb_orphan(skb);
nlk->handler(sk->sk_protocol, skb);
return 0;
} else
#endif
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
!test_bit(0, &nlk->state)) {
skb_orphan(skb);
skb_set_owner_r(skb, sk);
skb_queue_tail(&sk->sk_receive_queue, skb);
sk->sk_data_ready(sk, skb->len);
return 0;
}
return -1;
}
int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
u32 group, int allocation)
{
struct sock *sk;
struct hlist_node *node;
struct sk_buff *skb2 = NULL;
int protocol = ssk->sk_protocol;
int failure = 0, delivered = 0;
/* While we sleep in clone, do not allow to change socket list */
netlink_lock_table();
sk_for_each(sk, node, &nl_table[protocol]) {
struct netlink_opt *nlk = nlk_sk(sk);
if (ssk == sk)
continue;
if (nlk->pid == pid || !(nlk->groups & group))
continue;
if (failure) {
netlink_overrun(sk);
continue;
}
sock_hold(sk);
if (skb2 == NULL) {
if (atomic_read(&skb->users) != 1) {
skb2 = skb_clone(skb, allocation);
} else {
skb2 = skb;
atomic_inc(&skb->users);
}
}
if (skb2 == NULL) {
netlink_overrun(sk);
/* Clone failed. Notify ALL listeners. */
failure = 1;
} else if (netlink_broadcast_deliver(sk, skb2)) {
netlink_overrun(sk);
} else {
delivered = 1;
skb2 = NULL;
}
sock_put(sk);
}
netlink_unlock_table();
if (skb2)
kfree_skb(skb2);
kfree_skb(skb);
if (delivered)
return 0;
if (failure)
return -ENOBUFS;
return -ESRCH;
}
void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
{
struct sock *sk;
struct hlist_node *node;
int protocol = ssk->sk_protocol;
read_lock(&nl_table_lock);
sk_for_each(sk, node, &nl_table[protocol]) {
struct netlink_opt *nlk = nlk_sk(sk);
if (ssk == sk)
continue;
if (nlk->pid == pid || !(nlk->groups & group))
continue;
sk->sk_err = code;
sk->sk_error_report(sk);
}
read_unlock(&nl_table_lock);
}
static inline void netlink_rcv_wake(struct sock *sk)
{
struct netlink_opt *nlk = nlk_sk(sk);
if (!skb_queue_len(&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, int len)
{
struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
struct sock *sk = sock->sk;
struct netlink_opt *nlk = nlk_sk(sk);
struct sockaddr_nl *addr=msg->msg_name;
u32 dst_pid;
u32 dst_groups;
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_groups = addr->nl_groups;
if (dst_groups && !netlink_capable(sock, NL_NONROOT_SEND))
return -EPERM;
} else {
dst_pid = nlk->dst_pid;
dst_groups = nlk->dst_groups;
}
if (!nlk->pid) {
err = netlink_autobind(sock);
if (err)
goto out;
}
err = -EMSGSIZE;
if ((unsigned)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).groups = nlk->groups;
NETLINK_CB(skb).dst_pid = dst_pid;
NETLINK_CB(skb).dst_groups = dst_groups;
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 = security_netlink_send(skb);
if (err) {
kfree_skb(skb);
goto out;
}
err = -EFAULT;
if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) {
kfree_skb(skb);
goto out;
}
if (dst_groups) {
atomic_inc(&skb->users);
netlink_broadcast(sk, skb, dst_pid, dst_groups, 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, int len,
int flags)
{
struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
struct scm_cookie scm;
struct sock *sk = sock->sk;
struct netlink_opt *nlk = nlk_sk(sk);
int noblock = flags&MSG_DONTWAIT;
int 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_CB(skb).dst_groups;
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);
out:
netlink_rcv_wake(sk);
return err ? : copied;
}
void netlink_data_ready(struct sock *sk, int len)
{
struct netlink_opt *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, void (*input)(struct sock *sk, int len))
{
struct socket *sock;
struct sock *sk;
if (unit<0 || unit>=MAX_LINKS)
return NULL;
if (!(sock = sock_alloc()))
return NULL;
sock->type = SOCK_RAW;
if (netlink_create(sock, unit) < 0) {
sock_release(sock);
return NULL;
}
sk = sock->sk;
sk->sk_data_ready = netlink_data_ready;
if (input)
nlk_sk(sk)->data_ready = input;
netlink_insert(sk, 0);
return sk;
}
void netlink_set_nonroot(int protocol, unsigned flags)
{
if ((unsigned)protocol < MAX_LINKS)
nl_nonroot[protocol] = 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_opt *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_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq, NLMSG_DONE, sizeof(int));
nlh->nlmsg_flags |= 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);
cb->done(cb);
nlk->cb = NULL;
spin_unlock(&nlk->cb_lock);
netlink_destroy_callback(cb);
sock_put(sk);
return 0;
}
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_opt *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);
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));
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);
}
#ifdef NL_EMULATE_DEV
static rwlock_t nl_emu_lock = RW_LOCK_UNLOCKED;
/*
* Backward compatibility.
*/
int netlink_attach(int unit, int (*function)(int, struct sk_buff *skb))
{
struct sock *sk = netlink_kernel_create(unit, NULL);
if (sk == NULL)
return -ENOBUFS;
nlk_sk(sk)->handler = function;
write_lock_bh(&nl_emu_lock);
netlink_kernel[unit] = sk->sk_socket;
write_unlock_bh(&nl_emu_lock);
return 0;
}
void netlink_detach(int unit)
{
struct socket *sock;
write_lock_bh(&nl_emu_lock);
sock = netlink_kernel[unit];
netlink_kernel[unit] = NULL;
write_unlock_bh(&nl_emu_lock);
sock_release(sock);
}
int netlink_post(int unit, struct sk_buff *skb)
{
struct socket *sock;
read_lock(&nl_emu_lock);
sock = netlink_kernel[unit];
if (sock) {
struct sock *sk = sock->sk;
memset(skb->cb, 0, sizeof(skb->cb));
sock_hold(sk);
read_unlock(&nl_emu_lock);
netlink_broadcast(sk, skb, 0, ~0, GFP_ATOMIC);
sock_put(sk);
return 0;
}
read_unlock(&nl_emu_lock);
return -EUNATCH;
}
#endif
#ifdef CONFIG_PROC_FS
static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
{
long i;
struct sock *s;
struct hlist_node *node;
loff_t off = 0;
for (i=0; i<MAX_LINKS; i++) {
sk_for_each(s, node, &nl_table[i]) {
if (off == pos) {
seq->private = (void *) i;
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;
++*pos;
if (v == SEQ_START_TOKEN)
return netlink_seq_socket_idx(seq, 0);
s = sk_next(v);
if (!s) {
long i = (long)seq->private;
while (++i < MAX_LINKS) {
s = sk_head(&nl_table[i]);
if (s) {
seq->private = (void *) i;
break;
}
}
}
return s;
}
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_opt *nlk = nlk_sk(s);
seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
s,
s->sk_protocol,
nlk->pid,
nlk->groups,
atomic_read(&s->sk_rmem_alloc),
atomic_read(&s->sk_wmem_alloc),
nlk->cb,
atomic_read(&s->sk_refcnt)
);
}
return 0;
}
struct seq_operations netlink_seq_ops = {
.start = netlink_seq_start,
.next = netlink_seq_next,
.stop = netlink_seq_stop,
.show = netlink_seq_show,
};
static int netlink_seq_open(struct inode *inode, struct file *file)
{
return seq_open(file, &netlink_seq_ops);
}
static struct file_operations netlink_seq_fops = {
.owner = THIS_MODULE,
.open = netlink_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#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);
}
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 = sock_no_setsockopt,
.getsockopt = sock_no_getsockopt,
.sendmsg = netlink_sendmsg,
.recvmsg = netlink_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
};
struct net_proto_family netlink_family_ops = {
.family = PF_NETLINK,
.create = netlink_create,
.owner = THIS_MODULE, /* for consistency 8) */
};
static int __init netlink_proto_init(void)
{
struct sk_buff *dummy_skb;
if (sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb)) {
printk(KERN_CRIT "netlink_init: panic\n");
return -1;
}
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();
return 0;
}
static void __exit netlink_proto_exit(void)
{
sock_unregister(PF_NETLINK);
proc_net_remove("netlink");
}
core_initcall(netlink_proto_init);
module_exit(netlink_proto_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_NETLINK);
EXPORT_SYMBOL(netlink_ack);
EXPORT_SYMBOL(netlink_broadcast);
EXPORT_SYMBOL(netlink_broadcast_deliver);
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);
#if defined(CONFIG_NETLINK_DEV) || defined(CONFIG_NETLINK_DEV_MODULE)
EXPORT_SYMBOL(netlink_attach);
EXPORT_SYMBOL(netlink_detach);
EXPORT_SYMBOL(netlink_post);
#endif
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