summaryrefslogtreecommitdiff
path: root/net/netlink/af_netlink.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/netlink/af_netlink.c')
-rw-r--r--net/netlink/af_netlink.c2182
1 files changed, 2182 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
new file mode 100644
index 00000000..59debb73
--- /dev/null
+++ b/net/netlink/af_netlink.c
@@ -0,0 +1,2182 @@
+/*
+ * NETLINK Kernel-user communication protocol.
+ *
+ * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
+ * 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/module.h>
+
+#include <linux/capability.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/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 <linux/mutex.h>
+
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include <net/scm.h>
+#include <net/netlink.h>
+
+#define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
+#define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long))
+
+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;
+ struct mutex *cb_mutex;
+ struct mutex cb_def_mutex;
+ void (*netlink_rcv)(struct sk_buff *skb);
+ struct module *module;
+};
+
+struct listeners {
+ struct rcu_head rcu;
+ unsigned long masks[0];
+};
+
+#define NETLINK_KERNEL_SOCKET 0x1
+#define NETLINK_RECV_PKTINFO 0x2
+#define NETLINK_BROADCAST_SEND_ERROR 0x4
+#define NETLINK_RECV_NO_ENOBUFS 0x8
+
+static inline struct netlink_sock *nlk_sk(struct sock *sk)
+{
+ return container_of(sk, struct netlink_sock, sk);
+}
+
+static inline int netlink_is_kernel(struct sock *sk)
+{
+ return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
+}
+
+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;
+ struct listeners __rcu *listeners;
+ unsigned int nl_nonroot;
+ unsigned int groups;
+ struct mutex *cb_mutex;
+ 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 ATOMIC_NOTIFIER_HEAD(netlink_chain);
+
+static inline u32 netlink_group_mask(u32 group)
+{
+ return group ? 1 << (group - 1) : 0;
+}
+
+static inline 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)
+{
+ struct netlink_sock *nlk = nlk_sk(sk);
+
+ if (nlk->cb) {
+ if (nlk->cb->done)
+ nlk->cb->done(nlk->cb);
+ netlink_destroy_callback(nlk->cb);
+ }
+
+ skb_queue_purge(&sk->sk_receive_queue);
+
+ if (!sock_flag(sk, SOCK_DEAD)) {
+ printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
+ return;
+ }
+
+ WARN_ON(atomic_read(&sk->sk_rmem_alloc));
+ WARN_ON(atomic_read(&sk->sk_wmem_alloc));
+ WARN_ON(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.
+ */
+
+void netlink_table_grab(void)
+ __acquires(nl_table_lock)
+{
+ might_sleep();
+
+ write_lock_irq(&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_irq(&nl_table_lock);
+ schedule();
+ write_lock_irq(&nl_table_lock);
+ }
+
+ __set_current_state(TASK_RUNNING);
+ remove_wait_queue(&nl_table_wait, &wait);
+ }
+}
+
+void netlink_table_ungrab(void)
+ __releases(nl_table_lock)
+{
+ write_unlock_irq(&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 struct sock *netlink_lookup(struct net *net, 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 (net_eq(sock_net(sk), net) && (nlk_sk(sk)->pid == pid)) {
+ sock_hold(sk);
+ goto found;
+ }
+ }
+ sk = NULL;
+found:
+ read_unlock(&nl_table_lock);
+ return sk;
+}
+
+static struct hlist_head *nl_pid_hash_zalloc(size_t size)
+{
+ if (size <= PAGE_SIZE)
+ return kzalloc(size, GFP_ATOMIC);
+ else
+ return (struct hlist_head *)
+ __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
+ get_order(size));
+}
+
+static 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_zalloc(size);
+ if (!table)
+ return 0;
+
+ 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 const struct proto_ops netlink_ops;
+
+static void
+netlink_update_listeners(struct sock *sk)
+{
+ struct netlink_table *tbl = &nl_table[sk->sk_protocol];
+ struct hlist_node *node;
+ unsigned long mask;
+ unsigned int i;
+
+ for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
+ mask = 0;
+ sk_for_each_bound(sk, node, &tbl->mc_list) {
+ if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
+ mask |= nlk_sk(sk)->groups[i];
+ }
+ tbl->listeners->masks[i] = mask;
+ }
+ /* this function is only called with the netlink table "grabbed", which
+ * makes sure updates are visible before bind or setsockopt return. */
+}
+
+static int netlink_insert(struct sock *sk, struct net *net, 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 (net_eq(sock_net(osk), net) && (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 net *net, struct socket *sock,
+ struct mutex *cb_mutex, int protocol)
+{
+ struct sock *sk;
+ struct netlink_sock *nlk;
+
+ sock->ops = &netlink_ops;
+
+ sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
+ if (!sk)
+ return -ENOMEM;
+
+ sock_init_data(sock, sk);
+
+ nlk = nlk_sk(sk);
+ if (cb_mutex)
+ nlk->cb_mutex = cb_mutex;
+ else {
+ nlk->cb_mutex = &nlk->cb_def_mutex;
+ mutex_init(nlk->cb_mutex);
+ }
+ init_waitqueue_head(&nlk->wait);
+
+ sk->sk_destruct = netlink_sock_destruct;
+ sk->sk_protocol = protocol;
+ return 0;
+}
+
+static int netlink_create(struct net *net, struct socket *sock, int protocol,
+ int kern)
+{
+ struct module *module = NULL;
+ struct mutex *cb_mutex;
+ struct netlink_sock *nlk;
+ 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_MODULES
+ 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;
+ else
+ err = -EPROTONOSUPPORT;
+ cb_mutex = nl_table[protocol].cb_mutex;
+ netlink_unlock_table();
+
+ if (err < 0)
+ goto out;
+
+ err = __netlink_create(net, sock, cb_mutex, protocol);
+ if (err < 0)
+ goto out_module;
+
+ local_bh_disable();
+ sock_prot_inuse_add(net, &netlink_proto, 1);
+ local_bh_enable();
+
+ 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);
+ sock_orphan(sk);
+ nlk = nlk_sk(sk);
+
+ /*
+ * OK. Socket is unlinked, any packets that arrive now
+ * will be purged.
+ */
+
+ sock->sk = NULL;
+ wake_up_interruptible_all(&nlk->wait);
+
+ skb_queue_purge(&sk->sk_write_queue);
+
+ if (nlk->pid) {
+ struct netlink_notify n = {
+ .net = sock_net(sk),
+ .protocol = sk->sk_protocol,
+ .pid = nlk->pid,
+ };
+ atomic_notifier_call_chain(&netlink_chain,
+ NETLINK_URELEASE, &n);
+ }
+
+ module_put(nlk->module);
+
+ netlink_table_grab();
+ if (netlink_is_kernel(sk)) {
+ BUG_ON(nl_table[sk->sk_protocol].registered == 0);
+ if (--nl_table[sk->sk_protocol].registered == 0) {
+ kfree(nl_table[sk->sk_protocol].listeners);
+ nl_table[sk->sk_protocol].module = NULL;
+ nl_table[sk->sk_protocol].registered = 0;
+ }
+ } else if (nlk->subscriptions)
+ netlink_update_listeners(sk);
+ netlink_table_ungrab();
+
+ kfree(nlk->groups);
+ nlk->groups = NULL;
+
+ local_bh_disable();
+ sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
+ local_bh_enable();
+ sock_put(sk);
+ return 0;
+}
+
+static int netlink_autobind(struct socket *sock)
+{
+ struct sock *sk = sock->sk;
+ struct net *net = sock_net(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 = task_tgid_vnr(current);
+ 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 (!net_eq(sock_net(osk), net))
+ continue;
+ if (nlk_sk(osk)->pid == pid) {
+ /* Bind collision, search negative pid values. */
+ pid = rover--;
+ if (rover > -4097)
+ rover = -4097;
+ netlink_table_ungrab();
+ goto retry;
+ }
+ }
+ netlink_table_ungrab();
+
+ err = netlink_insert(sk, net, pid);
+ if (err == -EADDRINUSE)
+ goto retry;
+
+ /* If 2 threads race to autobind, that is fine. */
+ if (err == -EBUSY)
+ err = 0;
+
+ return err;
+}
+
+static inline int netlink_capable(const struct socket *sock, unsigned int flag)
+{
+ return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
+ capable(CAP_NET_ADMIN);
+}
+
+static void
+netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
+{
+ struct netlink_sock *nlk = nlk_sk(sk);
+
+ if (nlk->subscriptions && !subscriptions)
+ __sk_del_bind_node(sk);
+ else if (!nlk->subscriptions && subscriptions)
+ sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
+ nlk->subscriptions = subscriptions;
+}
+
+static int netlink_realloc_groups(struct sock *sk)
+{
+ struct netlink_sock *nlk = nlk_sk(sk);
+ unsigned int groups;
+ unsigned long *new_groups;
+ int err = 0;
+
+ netlink_table_grab();
+
+ groups = nl_table[sk->sk_protocol].groups;
+ if (!nl_table[sk->sk_protocol].registered) {
+ err = -ENOENT;
+ goto out_unlock;
+ }
+
+ if (nlk->ngroups >= groups)
+ goto out_unlock;
+
+ new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
+ if (new_groups == NULL) {
+ err = -ENOMEM;
+ goto out_unlock;
+ }
+ memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
+ NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
+
+ nlk->groups = new_groups;
+ nlk->ngroups = groups;
+ out_unlock:
+ netlink_table_ungrab();
+ return err;
+}
+
+static int netlink_bind(struct socket *sock, struct sockaddr *addr,
+ int addr_len)
+{
+ struct sock *sk = sock->sk;
+ struct net *net = sock_net(sk);
+ struct netlink_sock *nlk = nlk_sk(sk);
+ struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
+ int err;
+
+ if (nladdr->nl_family != AF_NETLINK)
+ return -EINVAL;
+
+ /* Only superuser is allowed to listen multicasts */
+ if (nladdr->nl_groups) {
+ if (!netlink_capable(sock, NL_NONROOT_RECV))
+ return -EPERM;
+ err = netlink_realloc_groups(sk);
+ if (err)
+ return err;
+ }
+
+ if (nlk->pid) {
+ if (nladdr->nl_pid != nlk->pid)
+ return -EINVAL;
+ } else {
+ err = nladdr->nl_pid ?
+ netlink_insert(sk, net, nladdr->nl_pid) :
+ netlink_autobind(sock);
+ if (err)
+ return err;
+ }
+
+ if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
+ return 0;
+
+ netlink_table_grab();
+ netlink_update_subscriptions(sk, nlk->subscriptions +
+ hweight32(nladdr->nl_groups) -
+ hweight32(nlk->groups[0]));
+ nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
+ netlink_update_listeners(sk);
+ netlink_table_ungrab();
+
+ return 0;
+}
+
+static int netlink_connect(struct socket *sock, struct sockaddr *addr,
+ int alen, int flags)
+{
+ int err = 0;
+ struct sock *sk = sock->sk;
+ struct netlink_sock *nlk = nlk_sk(sk);
+ struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
+
+ if (alen < sizeof(addr->sa_family))
+ return -EINVAL;
+
+ 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);
+ DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, 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)
+{
+ struct netlink_sock *nlk = nlk_sk(sk);
+
+ if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
+ if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
+ sk->sk_err = ENOBUFS;
+ sk->sk_error_report(sk);
+ }
+ }
+ atomic_inc(&sk->sk_drops);
+}
+
+static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
+{
+ struct sock *sock;
+ struct netlink_sock *nlk;
+
+ sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid);
+ if (!sock)
+ return ERR_PTR(-ECONNREFUSED);
+
+ /* Don't bother queuing skb if kernel socket has no input function */
+ nlk = nlk_sk(sock);
+ if (sock->sk_state == NETLINK_CONNECTED &&
+ nlk->dst_pid != nlk_sk(ssk)->pid) {
+ sock_put(sock);
+ return ERR_PTR(-ECONNREFUSED);
+ }
+ return sock;
+}
+
+struct sock *netlink_getsockbyfilp(struct file *filp)
+{
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ struct sock *sock;
+
+ if (!S_ISSOCK(inode->i_mode))
+ return ERR_PTR(-ENOTSOCK);
+
+ sock = SOCKET_I(inode)->sk;
+ if (sock->sk_family != AF_NETLINK)
+ return ERR_PTR(-EINVAL);
+
+ sock_hold(sock);
+ return sock;
+}
+
+/*
+ * Attach a skb to a netlink socket.
+ * The caller must hold a reference to the destination socket. On error, the
+ * reference is dropped. The skb is not send to the destination, just all
+ * all error checks are performed and memory in the queue is reserved.
+ * Return values:
+ * < 0: error. skb freed, reference to sock dropped.
+ * 0: continue
+ * 1: repeat lookup - reference dropped while waiting for socket memory.
+ */
+int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
+ long *timeo, struct sock *ssk)
+{
+ struct netlink_sock *nlk;
+
+ nlk = nlk_sk(sk);
+
+ if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
+ test_bit(0, &nlk->state)) {
+ DECLARE_WAITQUEUE(wait, current);
+ if (!*timeo) {
+ if (!ssk || netlink_is_kernel(ssk))
+ netlink_overrun(sk);
+ sock_put(sk);
+ kfree_skb(skb);
+ return -EAGAIN;
+ }
+
+ __set_current_state(TASK_INTERRUPTIBLE);
+ add_wait_queue(&nlk->wait, &wait);
+
+ if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
+ test_bit(0, &nlk->state)) &&
+ !sock_flag(sk, SOCK_DEAD))
+ *timeo = schedule_timeout(*timeo);
+
+ __set_current_state(TASK_RUNNING);
+ remove_wait_queue(&nlk->wait, &wait);
+ sock_put(sk);
+
+ if (signal_pending(current)) {
+ kfree_skb(skb);
+ return sock_intr_errno(*timeo);
+ }
+ return 1;
+ }
+ skb_set_owner_r(skb, sk);
+ return 0;
+}
+
+static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
+{
+ int len = skb->len;
+
+ skb_queue_tail(&sk->sk_receive_queue, skb);
+ sk->sk_data_ready(sk, len);
+ return len;
+}
+
+int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
+{
+ int len = __netlink_sendskb(sk, skb);
+
+ sock_put(sk);
+ return len;
+}
+
+void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
+{
+ kfree_skb(skb);
+ sock_put(sk);
+}
+
+static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
+{
+ int delta;
+
+ skb_orphan(skb);
+
+ delta = skb->end - skb->tail;
+ if (delta * 2 < skb->truesize)
+ return skb;
+
+ if (skb_shared(skb)) {
+ struct sk_buff *nskb = skb_clone(skb, allocation);
+ if (!nskb)
+ return skb;
+ kfree_skb(skb);
+ skb = nskb;
+ }
+
+ if (!pskb_expand_head(skb, 0, -delta, allocation))
+ skb->truesize -= delta;
+
+ return skb;
+}
+
+static 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_unicast_kernel(struct sock *sk, struct sk_buff *skb)
+{
+ int ret;
+ struct netlink_sock *nlk = nlk_sk(sk);
+
+ ret = -ECONNREFUSED;
+ if (nlk->netlink_rcv != NULL) {
+ ret = skb->len;
+ skb_set_owner_r(skb, sk);
+ nlk->netlink_rcv(skb);
+ }
+ kfree_skb(skb);
+ sock_put(sk);
+ return ret;
+}
+
+int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
+ u32 pid, int nonblock)
+{
+ struct sock *sk;
+ int err;
+ long timeo;
+
+ skb = netlink_trim(skb, gfp_any());
+
+ timeo = sock_sndtimeo(ssk, nonblock);
+retry:
+ sk = netlink_getsockbypid(ssk, pid);
+ if (IS_ERR(sk)) {
+ kfree_skb(skb);
+ return PTR_ERR(sk);
+ }
+ if (netlink_is_kernel(sk))
+ return netlink_unicast_kernel(sk, skb);
+
+ if (sk_filter(sk, skb)) {
+ err = skb->len;
+ kfree_skb(skb);
+ sock_put(sk);
+ return err;
+ }
+
+ err = netlink_attachskb(sk, skb, &timeo, ssk);
+ if (err == 1)
+ goto retry;
+ if (err)
+ return err;
+
+ return netlink_sendskb(sk, skb);
+}
+EXPORT_SYMBOL(netlink_unicast);
+
+int netlink_has_listeners(struct sock *sk, unsigned int group)
+{
+ int res = 0;
+ struct listeners *listeners;
+
+ BUG_ON(!netlink_is_kernel(sk));
+
+ rcu_read_lock();
+ listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
+
+ if (group - 1 < nl_table[sk->sk_protocol].groups)
+ res = test_bit(group - 1, listeners->masks);
+
+ rcu_read_unlock();
+
+ return res;
+}
+EXPORT_SYMBOL_GPL(netlink_has_listeners);
+
+static 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);
+ __netlink_sendskb(sk, skb);
+ return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
+ }
+ return -1;
+}
+
+struct netlink_broadcast_data {
+ struct sock *exclude_sk;
+ struct net *net;
+ u32 pid;
+ u32 group;
+ int failure;
+ int delivery_failure;
+ int congested;
+ int delivered;
+ gfp_t allocation;
+ struct sk_buff *skb, *skb2;
+ int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
+ void *tx_data;
+};
+
+static int do_one_broadcast(struct sock *sk,
+ struct netlink_broadcast_data *p)
+{
+ struct netlink_sock *nlk = nlk_sk(sk);
+ int val;
+
+ if (p->exclude_sk == sk)
+ goto out;
+
+ if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
+ !test_bit(p->group - 1, nlk->groups))
+ goto out;
+
+ if (!net_eq(sock_net(sk), p->net))
+ goto out;
+
+ if (p->failure) {
+ netlink_overrun(sk);
+ goto out;
+ }
+
+ sock_hold(sk);
+ if (p->skb2 == NULL) {
+ if (skb_shared(p->skb)) {
+ p->skb2 = skb_clone(p->skb, p->allocation);
+ } else {
+ p->skb2 = skb_get(p->skb);
+ /*
+ * skb ownership may have been set when
+ * delivered to a previous socket.
+ */
+ skb_orphan(p->skb2);
+ }
+ }
+ if (p->skb2 == NULL) {
+ netlink_overrun(sk);
+ /* Clone failed. Notify ALL listeners. */
+ p->failure = 1;
+ if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
+ p->delivery_failure = 1;
+ } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
+ kfree_skb(p->skb2);
+ p->skb2 = NULL;
+ } else if (sk_filter(sk, p->skb2)) {
+ kfree_skb(p->skb2);
+ p->skb2 = NULL;
+ } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
+ netlink_overrun(sk);
+ if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
+ p->delivery_failure = 1;
+ } else {
+ p->congested |= val;
+ p->delivered = 1;
+ p->skb2 = NULL;
+ }
+ sock_put(sk);
+
+out:
+ return 0;
+}
+
+int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 pid,
+ u32 group, gfp_t allocation,
+ int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
+ void *filter_data)
+{
+ struct net *net = sock_net(ssk);
+ struct netlink_broadcast_data info;
+ struct hlist_node *node;
+ struct sock *sk;
+
+ skb = netlink_trim(skb, allocation);
+
+ info.exclude_sk = ssk;
+ info.net = net;
+ info.pid = pid;
+ info.group = group;
+ info.failure = 0;
+ info.delivery_failure = 0;
+ info.congested = 0;
+ info.delivered = 0;
+ info.allocation = allocation;
+ info.skb = skb;
+ info.skb2 = NULL;
+ info.tx_filter = filter;
+ info.tx_data = filter_data;
+
+ /* 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);
+
+ consume_skb(skb);
+
+ netlink_unlock_table();
+
+ if (info.delivery_failure) {
+ kfree_skb(info.skb2);
+ return -ENOBUFS;
+ } else
+ consume_skb(info.skb2);
+
+ if (info.delivered) {
+ if (info.congested && (allocation & __GFP_WAIT))
+ yield();
+ return 0;
+ }
+ return -ESRCH;
+}
+EXPORT_SYMBOL(netlink_broadcast_filtered);
+
+int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
+ u32 group, gfp_t allocation)
+{
+ return netlink_broadcast_filtered(ssk, skb, pid, group, allocation,
+ NULL, NULL);
+}
+EXPORT_SYMBOL(netlink_broadcast);
+
+struct netlink_set_err_data {
+ struct sock *exclude_sk;
+ u32 pid;
+ u32 group;
+ int code;
+};
+
+static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
+{
+ struct netlink_sock *nlk = nlk_sk(sk);
+ int ret = 0;
+
+ if (sk == p->exclude_sk)
+ goto out;
+
+ if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
+ goto out;
+
+ if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
+ !test_bit(p->group - 1, nlk->groups))
+ goto out;
+
+ if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
+ ret = 1;
+ goto out;
+ }
+
+ sk->sk_err = p->code;
+ sk->sk_error_report(sk);
+out:
+ return ret;
+}
+
+/**
+ * netlink_set_err - report error to broadcast listeners
+ * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
+ * @pid: the PID of a process that we want to skip (if any)
+ * @groups: the broadcast group that will notice the error
+ * @code: error code, must be negative (as usual in kernelspace)
+ *
+ * This function returns the number of broadcast listeners that have set the
+ * NETLINK_RECV_NO_ENOBUFS socket option.
+ */
+int 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;
+ int ret = 0;
+
+ info.exclude_sk = ssk;
+ info.pid = pid;
+ info.group = group;
+ /* sk->sk_err wants a positive error value */
+ info.code = -code;
+
+ read_lock(&nl_table_lock);
+
+ sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
+ ret += do_one_set_err(sk, &info);
+
+ read_unlock(&nl_table_lock);
+ return ret;
+}
+EXPORT_SYMBOL(netlink_set_err);
+
+/* must be called with netlink table grabbed */
+static void netlink_update_socket_mc(struct netlink_sock *nlk,
+ unsigned int group,
+ int is_new)
+{
+ int old, new = !!is_new, subscriptions;
+
+ old = test_bit(group - 1, nlk->groups);
+ subscriptions = nlk->subscriptions - old + new;
+ if (new)
+ __set_bit(group - 1, nlk->groups);
+ else
+ __clear_bit(group - 1, nlk->groups);
+ netlink_update_subscriptions(&nlk->sk, subscriptions);
+ netlink_update_listeners(&nlk->sk);
+}
+
+static int netlink_setsockopt(struct socket *sock, int level, int optname,
+ char __user *optval, unsigned int optlen)
+{
+ struct sock *sk = sock->sk;
+ struct netlink_sock *nlk = nlk_sk(sk);
+ unsigned int val = 0;
+ int err;
+
+ if (level != SOL_NETLINK)
+ return -ENOPROTOOPT;
+
+ if (optlen >= sizeof(int) &&
+ get_user(val, (unsigned int __user *)optval))
+ return -EFAULT;
+
+ switch (optname) {
+ case NETLINK_PKTINFO:
+ if (val)
+ nlk->flags |= NETLINK_RECV_PKTINFO;
+ else
+ nlk->flags &= ~NETLINK_RECV_PKTINFO;
+ err = 0;
+ break;
+ case NETLINK_ADD_MEMBERSHIP:
+ case NETLINK_DROP_MEMBERSHIP: {
+ if (!netlink_capable(sock, NL_NONROOT_RECV))
+ return -EPERM;
+ err = netlink_realloc_groups(sk);
+ if (err)
+ return err;
+ if (!val || val - 1 >= nlk->ngroups)
+ return -EINVAL;
+ netlink_table_grab();
+ netlink_update_socket_mc(nlk, val,
+ optname == NETLINK_ADD_MEMBERSHIP);
+ netlink_table_ungrab();
+ err = 0;
+ break;
+ }
+ case NETLINK_BROADCAST_ERROR:
+ if (val)
+ nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
+ else
+ nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
+ err = 0;
+ break;
+ case NETLINK_NO_ENOBUFS:
+ if (val) {
+ nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
+ clear_bit(0, &nlk->state);
+ wake_up_interruptible(&nlk->wait);
+ } else
+ nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
+ err = 0;
+ break;
+ default:
+ err = -ENOPROTOOPT;
+ }
+ return err;
+}
+
+static int netlink_getsockopt(struct socket *sock, int level, int optname,
+ char __user *optval, int __user *optlen)
+{
+ struct sock *sk = sock->sk;
+ struct netlink_sock *nlk = nlk_sk(sk);
+ int len, val, err;
+
+ if (level != SOL_NETLINK)
+ return -ENOPROTOOPT;
+
+ if (get_user(len, optlen))
+ return -EFAULT;
+ if (len < 0)
+ return -EINVAL;
+
+ switch (optname) {
+ case NETLINK_PKTINFO:
+ if (len < sizeof(int))
+ return -EINVAL;
+ len = sizeof(int);
+ val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
+ if (put_user(len, optlen) ||
+ put_user(val, optval))
+ return -EFAULT;
+ err = 0;
+ break;
+ case NETLINK_BROADCAST_ERROR:
+ if (len < sizeof(int))
+ return -EINVAL;
+ len = sizeof(int);
+ val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
+ if (put_user(len, optlen) ||
+ put_user(val, optval))
+ return -EFAULT;
+ err = 0;
+ break;
+ case NETLINK_NO_ENOBUFS:
+ if (len < sizeof(int))
+ return -EINVAL;
+ len = sizeof(int);
+ val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
+ if (put_user(len, optlen) ||
+ put_user(val, optval))
+ return -EFAULT;
+ err = 0;
+ break;
+ default:
+ err = -ENOPROTOOPT;
+ }
+ return err;
+}
+
+static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
+{
+ struct nl_pktinfo info;
+
+ info.group = NETLINK_CB(skb).dst_group;
+ put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
+}
+
+static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
+ struct msghdr *msg, size_t len)
+{
+ struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
+ struct sock *sk = sock->sk;
+ struct netlink_sock *nlk = nlk_sk(sk);
+ struct sockaddr_nl *addr = msg->msg_name;
+ u32 dst_pid;
+ u32 dst_group;
+ struct sk_buff *skb;
+ int err;
+ struct scm_cookie scm;
+
+ if (msg->msg_flags&MSG_OOB)
+ return -EOPNOTSUPP;
+
+ if (NULL == siocb->scm)
+ siocb->scm = &scm;
+
+ err = scm_send(sock, msg, siocb->scm, true);
+ if (err < 0)
+ return err;
+
+ if (msg->msg_namelen) {
+ err = -EINVAL;
+ if (addr->nl_family != AF_NETLINK)
+ goto out;
+ dst_pid = addr->nl_pid;
+ dst_group = ffs(addr->nl_groups);
+ err = -EPERM;
+ if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
+ goto out;
+ } else {
+ dst_pid = nlk->dst_pid;
+ dst_group = nlk->dst_group;
+ }
+
+ if (!nlk->pid) {
+ err = netlink_autobind(sock);
+ if (err)
+ goto out;
+ }
+
+ err = -EMSGSIZE;
+ if (len > sk->sk_sndbuf - 32)
+ goto out;
+ err = -ENOBUFS;
+ skb = alloc_skb(len, GFP_KERNEL);
+ if (skb == NULL)
+ goto out;
+
+ NETLINK_CB(skb).pid = nlk->pid;
+ NETLINK_CB(skb).dst_group = dst_group;
+ memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
+
+ 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:
+ scm_destroy(siocb->scm);
+ 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, *data_skb;
+ int err, ret;
+
+ if (flags&MSG_OOB)
+ return -EOPNOTSUPP;
+
+ copied = 0;
+
+ skb = skb_recv_datagram(sk, flags, noblock, &err);
+ if (skb == NULL)
+ goto out;
+
+ data_skb = skb;
+
+#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
+ if (unlikely(skb_shinfo(skb)->frag_list)) {
+ /*
+ * If this skb has a frag_list, then here that means that we
+ * will have to use the frag_list skb's data for compat tasks
+ * and the regular skb's data for normal (non-compat) tasks.
+ *
+ * If we need to send the compat skb, assign it to the
+ * 'data_skb' variable so that it will be used below for data
+ * copying. We keep 'skb' for everything else, including
+ * freeing both later.
+ */
+ if (flags & MSG_CMSG_COMPAT)
+ data_skb = skb_shinfo(skb)->frag_list;
+ }
+#endif
+
+ msg->msg_namelen = 0;
+
+ copied = data_skb->len;
+ if (len < copied) {
+ msg->msg_flags |= MSG_TRUNC;
+ copied = len;
+ }
+
+ skb_reset_transport_header(data_skb);
+ err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
+
+ if (msg->msg_name) {
+ struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
+ addr->nl_family = AF_NETLINK;
+ addr->nl_pad = 0;
+ addr->nl_pid = NETLINK_CB(skb).pid;
+ addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
+ msg->msg_namelen = sizeof(*addr);
+ }
+
+ if (nlk->flags & NETLINK_RECV_PKTINFO)
+ netlink_cmsg_recv_pktinfo(msg, skb);
+
+ if (NULL == siocb->scm) {
+ memset(&scm, 0, sizeof(scm));
+ siocb->scm = &scm;
+ }
+ siocb->scm->creds = *NETLINK_CREDS(skb);
+ if (flags & MSG_TRUNC)
+ copied = data_skb->len;
+
+ skb_free_datagram(sk, skb);
+
+ if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
+ ret = netlink_dump(sk);
+ if (ret) {
+ sk->sk_err = ret;
+ sk->sk_error_report(sk);
+ }
+ }
+
+ scm_recv(sock, msg, siocb->scm, flags);
+out:
+ netlink_rcv_wake(sk);
+ return err ? : copied;
+}
+
+static void netlink_data_ready(struct sock *sk, int len)
+{
+ BUG();
+}
+
+/*
+ * We export these functions to other modules. They provide a
+ * complete set of kernel non-blocking support for message
+ * queueing.
+ */
+
+struct sock *
+netlink_kernel_create(struct net *net, int unit, unsigned int groups,
+ void (*input)(struct sk_buff *skb),
+ struct mutex *cb_mutex, struct module *module)
+{
+ struct socket *sock;
+ struct sock *sk;
+ struct netlink_sock *nlk;
+ struct listeners *listeners = NULL;
+
+ BUG_ON(!nl_table);
+
+ if (unit < 0 || unit >= MAX_LINKS)
+ return NULL;
+
+ if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
+ return NULL;
+
+ /*
+ * We have to just have a reference on the net from sk, but don't
+ * get_net it. Besides, we cannot get and then put the net here.
+ * So we create one inside init_net and the move it to net.
+ */
+
+ if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
+ goto out_sock_release_nosk;
+
+ sk = sock->sk;
+ sk_change_net(sk, net);
+
+ if (groups < 32)
+ groups = 32;
+
+ listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
+ if (!listeners)
+ goto out_sock_release;
+
+ sk->sk_data_ready = netlink_data_ready;
+ if (input)
+ nlk_sk(sk)->netlink_rcv = input;
+
+ if (netlink_insert(sk, net, 0))
+ goto out_sock_release;
+
+ nlk = nlk_sk(sk);
+ nlk->flags |= NETLINK_KERNEL_SOCKET;
+
+ netlink_table_grab();
+ if (!nl_table[unit].registered) {
+ nl_table[unit].groups = groups;
+ rcu_assign_pointer(nl_table[unit].listeners, listeners);
+ nl_table[unit].cb_mutex = cb_mutex;
+ nl_table[unit].module = module;
+ nl_table[unit].registered = 1;
+ } else {
+ kfree(listeners);
+ nl_table[unit].registered++;
+ }
+ netlink_table_ungrab();
+ return sk;
+
+out_sock_release:
+ kfree(listeners);
+ netlink_kernel_release(sk);
+ return NULL;
+
+out_sock_release_nosk:
+ sock_release(sock);
+ return NULL;
+}
+EXPORT_SYMBOL(netlink_kernel_create);
+
+
+void
+netlink_kernel_release(struct sock *sk)
+{
+ sk_release_kernel(sk);
+}
+EXPORT_SYMBOL(netlink_kernel_release);
+
+int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
+{
+ struct listeners *new, *old;
+ struct netlink_table *tbl = &nl_table[sk->sk_protocol];
+
+ if (groups < 32)
+ groups = 32;
+
+ if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
+ new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
+ if (!new)
+ return -ENOMEM;
+ old = rcu_dereference_protected(tbl->listeners, 1);
+ memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
+ rcu_assign_pointer(tbl->listeners, new);
+
+ kfree_rcu(old, rcu);
+ }
+ tbl->groups = groups;
+
+ return 0;
+}
+
+/**
+ * netlink_change_ngroups - change number of multicast groups
+ *
+ * This changes the number of multicast groups that are available
+ * on a certain netlink family. Note that it is not possible to
+ * change the number of groups to below 32. Also note that it does
+ * not implicitly call netlink_clear_multicast_users() when the
+ * number of groups is reduced.
+ *
+ * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
+ * @groups: The new number of groups.
+ */
+int netlink_change_ngroups(struct sock *sk, unsigned int groups)
+{
+ int err;
+
+ netlink_table_grab();
+ err = __netlink_change_ngroups(sk, groups);
+ netlink_table_ungrab();
+
+ return err;
+}
+
+void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
+{
+ struct sock *sk;
+ struct hlist_node *node;
+ struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
+
+ sk_for_each_bound(sk, node, &tbl->mc_list)
+ netlink_update_socket_mc(nlk_sk(sk), group, 0);
+}
+
+/**
+ * netlink_clear_multicast_users - kick off multicast listeners
+ *
+ * This function removes all listeners from the given group.
+ * @ksk: The kernel netlink socket, as returned by
+ * netlink_kernel_create().
+ * @group: The multicast group to clear.
+ */
+void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
+{
+ netlink_table_grab();
+ __netlink_clear_multicast_users(ksk, group);
+ netlink_table_ungrab();
+}
+
+void netlink_set_nonroot(int protocol, unsigned int flags)
+{
+ if ((unsigned int)protocol < MAX_LINKS)
+ nl_table[protocol].nl_nonroot = flags;
+}
+EXPORT_SYMBOL(netlink_set_nonroot);
+
+static void netlink_destroy_callback(struct netlink_callback *cb)
+{
+ kfree_skb(cb->skb);
+ kfree(cb);
+}
+
+struct nlmsghdr *
+__nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags)
+{
+ struct nlmsghdr *nlh;
+ int size = NLMSG_LENGTH(len);
+
+ nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
+ nlh->nlmsg_type = type;
+ nlh->nlmsg_len = size;
+ nlh->nlmsg_flags = flags;
+ nlh->nlmsg_pid = pid;
+ nlh->nlmsg_seq = seq;
+ if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
+ memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size);
+ return nlh;
+}
+EXPORT_SYMBOL(__nlmsg_put);
+
+/*
+ * 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 = NULL;
+ struct nlmsghdr *nlh;
+ int len, err = -ENOBUFS;
+ int alloc_size;
+
+ mutex_lock(nlk->cb_mutex);
+
+ cb = nlk->cb;
+ if (cb == NULL) {
+ err = -EINVAL;
+ goto errout_skb;
+ }
+
+ alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
+
+ skb = sock_rmalloc(sk, alloc_size, 0, GFP_KERNEL);
+ if (!skb)
+ goto errout_skb;
+
+ len = cb->dump(skb, cb);
+
+ if (len > 0) {
+ mutex_unlock(nlk->cb_mutex);
+
+ if (sk_filter(sk, skb))
+ kfree_skb(skb);
+ else
+ __netlink_sendskb(sk, skb);
+ return 0;
+ }
+
+ nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
+ if (!nlh)
+ goto errout_skb;
+
+ nl_dump_check_consistent(cb, nlh);
+
+ memcpy(nlmsg_data(nlh), &len, sizeof(len));
+
+ if (sk_filter(sk, skb))
+ kfree_skb(skb);
+ else
+ __netlink_sendskb(sk, skb);
+
+ if (cb->done)
+ cb->done(cb);
+ nlk->cb = NULL;
+ mutex_unlock(nlk->cb_mutex);
+
+ netlink_destroy_callback(cb);
+ return 0;
+
+errout_skb:
+ mutex_unlock(nlk->cb_mutex);
+ kfree_skb(skb);
+ return err;
+}
+
+int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
+ const struct nlmsghdr *nlh,
+ struct netlink_dump_control *control)
+{
+ struct netlink_callback *cb;
+ struct sock *sk;
+ struct netlink_sock *nlk;
+ int ret;
+
+ cb = kzalloc(sizeof(*cb), GFP_KERNEL);
+ if (cb == NULL)
+ return -ENOBUFS;
+
+ cb->dump = control->dump;
+ cb->done = control->done;
+ cb->nlh = nlh;
+ cb->data = control->data;
+ cb->min_dump_alloc = control->min_dump_alloc;
+ atomic_inc(&skb->users);
+ cb->skb = skb;
+
+ sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
+ if (sk == NULL) {
+ netlink_destroy_callback(cb);
+ return -ECONNREFUSED;
+ }
+ nlk = nlk_sk(sk);
+ /* A dump is in progress... */
+ mutex_lock(nlk->cb_mutex);
+ if (nlk->cb) {
+ mutex_unlock(nlk->cb_mutex);
+ netlink_destroy_callback(cb);
+ sock_put(sk);
+ return -EBUSY;
+ }
+ nlk->cb = cb;
+ mutex_unlock(nlk->cb_mutex);
+
+ ret = netlink_dump(sk);
+
+ sock_put(sk);
+
+ if (ret)
+ return ret;
+
+ /* We successfully started a dump, by returning -EINTR we
+ * signal not to send ACK even if it was requested.
+ */
+ return -EINTR;
+}
+EXPORT_SYMBOL(netlink_dump_start);
+
+void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
+{
+ struct sk_buff *skb;
+ struct nlmsghdr *rep;
+ struct nlmsgerr *errmsg;
+ size_t payload = sizeof(*errmsg);
+
+ /* error messages get the original request appened */
+ if (err)
+ payload += nlmsg_len(nlh);
+
+ skb = nlmsg_new(payload, GFP_KERNEL);
+ if (!skb) {
+ struct sock *sk;
+
+ sk = netlink_lookup(sock_net(in_skb->sk),
+ in_skb->sk->sk_protocol,
+ NETLINK_CB(in_skb).pid);
+ if (sk) {
+ sk->sk_err = ENOBUFS;
+ sk->sk_error_report(sk);
+ sock_put(sk);
+ }
+ return;
+ }
+
+ rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
+ NLMSG_ERROR, payload, 0);
+ errmsg = nlmsg_data(rep);
+ errmsg->error = err;
+ memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
+ netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
+}
+EXPORT_SYMBOL(netlink_ack);
+
+int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
+ struct nlmsghdr *))
+{
+ struct nlmsghdr *nlh;
+ int err;
+
+ while (skb->len >= nlmsg_total_size(0)) {
+ int msglen;
+
+ nlh = nlmsg_hdr(skb);
+ err = 0;
+
+ if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
+ return 0;
+
+ /* Only requests are handled by the kernel */
+ if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
+ goto ack;
+
+ /* Skip control messages */
+ if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
+ goto ack;
+
+ err = cb(skb, nlh);
+ if (err == -EINTR)
+ goto skip;
+
+ack:
+ if (nlh->nlmsg_flags & NLM_F_ACK || err)
+ netlink_ack(skb, nlh, err);
+
+skip:
+ msglen = NLMSG_ALIGN(nlh->nlmsg_len);
+ if (msglen > skb->len)
+ msglen = skb->len;
+ skb_pull(skb, msglen);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(netlink_rcv_skb);
+
+/**
+ * nlmsg_notify - send a notification netlink message
+ * @sk: netlink socket to use
+ * @skb: notification message
+ * @pid: destination netlink pid for reports or 0
+ * @group: destination multicast group or 0
+ * @report: 1 to report back, 0 to disable
+ * @flags: allocation flags
+ */
+int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
+ unsigned int group, int report, gfp_t flags)
+{
+ int err = 0;
+
+ if (group) {
+ int exclude_pid = 0;
+
+ if (report) {
+ atomic_inc(&skb->users);
+ exclude_pid = pid;
+ }
+
+ /* errors reported via destination sk->sk_err, but propagate
+ * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
+ err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
+ }
+
+ if (report) {
+ int err2;
+
+ err2 = nlmsg_unicast(sk, skb, pid);
+ if (!err || err == -ESRCH)
+ err = err2;
+ }
+
+ return err;
+}
+EXPORT_SYMBOL(nlmsg_notify);
+
+#ifdef CONFIG_PROC_FS
+struct nl_seq_iter {
+ struct seq_net_private p;
+ int link;
+ int hash_idx;
+};
+
+static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
+{
+ struct nl_seq_iter *iter = seq->private;
+ int i, j;
+ struct sock *s;
+ struct hlist_node *node;
+ loff_t off = 0;
+
+ for (i = 0; i < MAX_LINKS; i++) {
+ struct nl_pid_hash *hash = &nl_table[i].hash;
+
+ for (j = 0; j <= hash->mask; j++) {
+ sk_for_each(s, node, &hash->table[j]) {
+ if (sock_net(s) != seq_file_net(seq))
+ continue;
+ if (off == pos) {
+ iter->link = i;
+ iter->hash_idx = j;
+ return s;
+ }
+ ++off;
+ }
+ }
+ }
+ return NULL;
+}
+
+static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
+ __acquires(nl_table_lock)
+{
+ read_lock(&nl_table_lock);
+ return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
+}
+
+static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct sock *s;
+ struct nl_seq_iter *iter;
+ int i, j;
+
+ ++*pos;
+
+ if (v == SEQ_START_TOKEN)
+ return netlink_seq_socket_idx(seq, 0);
+
+ iter = seq->private;
+ s = v;
+ do {
+ s = sk_next(s);
+ } while (s && sock_net(s) != seq_file_net(seq));
+ if (s)
+ return s;
+
+ i = iter->link;
+ j = iter->hash_idx + 1;
+
+ do {
+ struct nl_pid_hash *hash = &nl_table[i].hash;
+
+ for (; j <= hash->mask; j++) {
+ s = sk_head(&hash->table[j]);
+ while (s && sock_net(s) != seq_file_net(seq))
+ s = sk_next(s);
+ if (s) {
+ iter->link = i;
+ iter->hash_idx = j;
+ return s;
+ }
+ }
+
+ j = 0;
+ } while (++i < MAX_LINKS);
+
+ return NULL;
+}
+
+static void netlink_seq_stop(struct seq_file *seq, void *v)
+ __releases(nl_table_lock)
+{
+ read_unlock(&nl_table_lock);
+}
+
+
+static int netlink_seq_show(struct seq_file *seq, void *v)
+{
+ if (v == SEQ_START_TOKEN)
+ seq_puts(seq,
+ "sk Eth Pid Groups "
+ "Rmem Wmem Dump Locks Drops Inode\n");
+ else {
+ struct sock *s = v;
+ struct netlink_sock *nlk = nlk_sk(s);
+
+ seq_printf(seq, "%pK %-3d %-6d %08x %-8d %-8d %pK %-8d %-8d %-8lu\n",
+ s,
+ s->sk_protocol,
+ nlk->pid,
+ nlk->groups ? (u32)nlk->groups[0] : 0,
+ sk_rmem_alloc_get(s),
+ sk_wmem_alloc_get(s),
+ nlk->cb,
+ atomic_read(&s->sk_refcnt),
+ atomic_read(&s->sk_drops),
+ sock_i_ino(s)
+ );
+
+ }
+ return 0;
+}
+
+static const struct seq_operations netlink_seq_ops = {
+ .start = netlink_seq_start,
+ .next = netlink_seq_next,
+ .stop = netlink_seq_stop,
+ .show = netlink_seq_show,
+};
+
+
+static int netlink_seq_open(struct inode *inode, struct file *file)
+{
+ return seq_open_net(inode, file, &netlink_seq_ops,
+ sizeof(struct nl_seq_iter));
+}
+
+static const struct file_operations netlink_seq_fops = {
+ .owner = THIS_MODULE,
+ .open = netlink_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release_net,
+};
+
+#endif
+
+int netlink_register_notifier(struct notifier_block *nb)
+{
+ return atomic_notifier_chain_register(&netlink_chain, nb);
+}
+EXPORT_SYMBOL(netlink_register_notifier);
+
+int netlink_unregister_notifier(struct notifier_block *nb)
+{
+ return atomic_notifier_chain_unregister(&netlink_chain, nb);
+}
+EXPORT_SYMBOL(netlink_unregister_notifier);
+
+static const struct proto_ops netlink_ops = {
+ .family = PF_NETLINK,
+ .owner = THIS_MODULE,
+ .release = netlink_release,
+ .bind = netlink_bind,
+ .connect = netlink_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = sock_no_accept,
+ .getname = netlink_getname,
+ .poll = datagram_poll,
+ .ioctl = sock_no_ioctl,
+ .listen = sock_no_listen,
+ .shutdown = sock_no_shutdown,
+ .setsockopt = netlink_setsockopt,
+ .getsockopt = netlink_getsockopt,
+ .sendmsg = netlink_sendmsg,
+ .recvmsg = netlink_recvmsg,
+ .mmap = sock_no_mmap,
+ .sendpage = sock_no_sendpage,
+};
+
+static const struct net_proto_family netlink_family_ops = {
+ .family = PF_NETLINK,
+ .create = netlink_create,
+ .owner = THIS_MODULE, /* for consistency 8) */
+};
+
+static int __net_init netlink_net_init(struct net *net)
+{
+#ifdef CONFIG_PROC_FS
+ if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
+ return -ENOMEM;
+#endif
+ return 0;
+}
+
+static void __net_exit netlink_net_exit(struct net *net)
+{
+#ifdef CONFIG_PROC_FS
+ proc_net_remove(net, "netlink");
+#endif
+}
+
+static void __init netlink_add_usersock_entry(void)
+{
+ struct listeners *listeners;
+ int groups = 32;
+
+ listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
+ if (!listeners)
+ panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
+
+ netlink_table_grab();
+
+ nl_table[NETLINK_USERSOCK].groups = groups;
+ rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
+ nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
+ nl_table[NETLINK_USERSOCK].registered = 1;
+
+ netlink_table_ungrab();
+}
+
+static struct pernet_operations __net_initdata netlink_net_ops = {
+ .init = netlink_net_init,
+ .exit = netlink_net_exit,
+};
+
+static int __init netlink_proto_init(void)
+{
+ struct sk_buff *dummy_skb;
+ int i;
+ unsigned long limit;
+ unsigned int order;
+ int err = proto_register(&netlink_proto, 0);
+
+ if (err != 0)
+ goto out;
+
+ BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
+
+ nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
+ if (!nl_table)
+ goto panic;
+
+ if (totalram_pages >= (128 * 1024))
+ limit = totalram_pages >> (21 - PAGE_SHIFT);
+ else
+ limit = totalram_pages >> (23 - PAGE_SHIFT);
+
+ order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
+ limit = (1UL << order) / sizeof(struct hlist_head);
+ order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
+
+ for (i = 0; i < MAX_LINKS; i++) {
+ struct nl_pid_hash *hash = &nl_table[i].hash;
+
+ hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
+ if (!hash->table) {
+ while (i-- > 0)
+ nl_pid_hash_free(nl_table[i].hash.table,
+ 1 * sizeof(*hash->table));
+ kfree(nl_table);
+ goto panic;
+ }
+ hash->max_shift = order;
+ hash->shift = 0;
+ hash->mask = 0;
+ hash->rehash_time = jiffies;
+ }
+
+ netlink_add_usersock_entry();
+
+ sock_register(&netlink_family_ops);
+ register_pernet_subsys(&netlink_net_ops);
+ /* The netlink device handler may be needed early. */
+ rtnetlink_init();
+out:
+ return err;
+panic:
+ panic("netlink_init: Cannot allocate nl_table\n");
+}
+
+core_initcall(netlink_proto_init);
generated by cgit (git 2.34.1) at 2024-12-20 11:13:02 +0000