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Diffstat (limited to 'net/netlink/af_netlink.c')
-rw-r--r--net/netlink/af_netlink.c178
1 files changed, 168 insertions, 10 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 57ee84d..0c61b59 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -57,6 +57,7 @@
#include <linux/audit.h>
#include <linux/mutex.h>
#include <linux/vmalloc.h>
+#include <linux/if_arp.h>
#include <asm/cacheflush.h>
#include <net/net_namespace.h>
@@ -101,6 +102,9 @@ static atomic_t nl_table_users = ATOMIC_INIT(0);
static ATOMIC_NOTIFIER_HEAD(netlink_chain);
+static DEFINE_SPINLOCK(netlink_tap_lock);
+static struct list_head netlink_tap_all __read_mostly;
+
static inline u32 netlink_group_mask(u32 group)
{
return group ? 1 << (group - 1) : 0;
@@ -111,6 +115,100 @@ static inline struct hlist_head *nl_portid_hashfn(struct nl_portid_hash *hash, u
return &hash->table[jhash_1word(portid, hash->rnd) & hash->mask];
}
+int netlink_add_tap(struct netlink_tap *nt)
+{
+ if (unlikely(nt->dev->type != ARPHRD_NETLINK))
+ return -EINVAL;
+
+ spin_lock(&netlink_tap_lock);
+ list_add_rcu(&nt->list, &netlink_tap_all);
+ spin_unlock(&netlink_tap_lock);
+
+ if (nt->module)
+ __module_get(nt->module);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(netlink_add_tap);
+
+int __netlink_remove_tap(struct netlink_tap *nt)
+{
+ bool found = false;
+ struct netlink_tap *tmp;
+
+ spin_lock(&netlink_tap_lock);
+
+ list_for_each_entry(tmp, &netlink_tap_all, list) {
+ if (nt == tmp) {
+ list_del_rcu(&nt->list);
+ found = true;
+ goto out;
+ }
+ }
+
+ pr_warn("__netlink_remove_tap: %p not found\n", nt);
+out:
+ spin_unlock(&netlink_tap_lock);
+
+ if (found && nt->module)
+ module_put(nt->module);
+
+ return found ? 0 : -ENODEV;
+}
+EXPORT_SYMBOL_GPL(__netlink_remove_tap);
+
+int netlink_remove_tap(struct netlink_tap *nt)
+{
+ int ret;
+
+ ret = __netlink_remove_tap(nt);
+ synchronize_net();
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(netlink_remove_tap);
+
+static int __netlink_deliver_tap_skb(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ struct sk_buff *nskb;
+ int ret = -ENOMEM;
+
+ dev_hold(dev);
+ nskb = skb_clone(skb, GFP_ATOMIC);
+ if (nskb) {
+ nskb->dev = dev;
+ ret = dev_queue_xmit(nskb);
+ if (unlikely(ret > 0))
+ ret = net_xmit_errno(ret);
+ }
+
+ dev_put(dev);
+ return ret;
+}
+
+static void __netlink_deliver_tap(struct sk_buff *skb)
+{
+ int ret;
+ struct netlink_tap *tmp;
+
+ list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
+ ret = __netlink_deliver_tap_skb(skb, tmp->dev);
+ if (unlikely(ret))
+ break;
+ }
+}
+
+static void netlink_deliver_tap(struct sk_buff *skb)
+{
+ rcu_read_lock();
+
+ if (unlikely(!list_empty(&netlink_tap_all)))
+ __netlink_deliver_tap(skb);
+
+ rcu_read_unlock();
+}
+
static void netlink_overrun(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
@@ -750,6 +848,13 @@ static void netlink_skb_destructor(struct sk_buff *skb)
skb->head = NULL;
}
#endif
+ if (is_vmalloc_addr(skb->head)) {
+ if (!skb->cloned ||
+ !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
+ vfree(skb->head);
+
+ skb->head = NULL;
+ }
if (skb->sk != NULL)
sock_rfree(skb);
}
@@ -854,16 +959,23 @@ netlink_unlock_table(void)
wake_up(&nl_table_wait);
}
+static bool netlink_compare(struct net *net, struct sock *sk)
+{
+ return net_eq(sock_net(sk), net);
+}
+
static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
{
- struct nl_portid_hash *hash = &nl_table[protocol].hash;
+ struct netlink_table *table = &nl_table[protocol];
+ struct nl_portid_hash *hash = &table->hash;
struct hlist_head *head;
struct sock *sk;
read_lock(&nl_table_lock);
head = nl_portid_hashfn(hash, portid);
sk_for_each(sk, head) {
- if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->portid == portid)) {
+ if (table->compare(net, sk) &&
+ (nlk_sk(sk)->portid == portid)) {
sock_hold(sk);
goto found;
}
@@ -976,7 +1088,8 @@ netlink_update_listeners(struct sock *sk)
static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
{
- struct nl_portid_hash *hash = &nl_table[sk->sk_protocol].hash;
+ struct netlink_table *table = &nl_table[sk->sk_protocol];
+ struct nl_portid_hash *hash = &table->hash;
struct hlist_head *head;
int err = -EADDRINUSE;
struct sock *osk;
@@ -986,7 +1099,8 @@ static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
head = nl_portid_hashfn(hash, portid);
len = 0;
sk_for_each(osk, head) {
- if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->portid == portid))
+ if (table->compare(net, osk) &&
+ (nlk_sk(osk)->portid == portid))
break;
len++;
}
@@ -1183,7 +1297,8 @@ static int netlink_autobind(struct socket *sock)
{
struct sock *sk = sock->sk;
struct net *net = sock_net(sk);
- struct nl_portid_hash *hash = &nl_table[sk->sk_protocol].hash;
+ struct netlink_table *table = &nl_table[sk->sk_protocol];
+ struct nl_portid_hash *hash = &table->hash;
struct hlist_head *head;
struct sock *osk;
s32 portid = task_tgid_vnr(current);
@@ -1195,7 +1310,7 @@ retry:
netlink_table_grab();
head = nl_portid_hashfn(hash, portid);
sk_for_each(osk, head) {
- if (!net_eq(sock_net(osk), net))
+ if (!table->compare(net, osk))
continue;
if (nlk_sk(osk)->portid == portid) {
/* Bind collision, search negative portid values. */
@@ -1420,6 +1535,33 @@ struct sock *netlink_getsockbyfilp(struct file *filp)
return sock;
}
+static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
+ int broadcast)
+{
+ struct sk_buff *skb;
+ void *data;
+
+ if (size <= NLMSG_GOODSIZE || broadcast)
+ return alloc_skb(size, GFP_KERNEL);
+
+ size = SKB_DATA_ALIGN(size) +
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+
+ data = vmalloc(size);
+ if (data == NULL)
+ return NULL;
+
+ skb = build_skb(data, size);
+ if (skb == NULL)
+ vfree(data);
+ else {
+ skb->head_frag = 0;
+ skb->destructor = netlink_skb_destructor;
+ }
+
+ return skb;
+}
+
/*
* Attach a skb to a netlink socket.
* The caller must hold a reference to the destination socket. On error, the
@@ -1475,6 +1617,8 @@ static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
{
int len = skb->len;
+ netlink_deliver_tap(skb);
+
#ifdef CONFIG_NETLINK_MMAP
if (netlink_skb_is_mmaped(skb))
netlink_queue_mmaped_skb(sk, skb);
@@ -1510,7 +1654,7 @@ static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
return skb;
delta = skb->end - skb->tail;
- if (delta * 2 < skb->truesize)
+ if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
return skb;
if (skb_shared(skb)) {
@@ -1535,6 +1679,11 @@ static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
ret = -ECONNREFUSED;
if (nlk->netlink_rcv != NULL) {
+ /* We could do a netlink_deliver_tap(skb) here as well
+ * but since this is intended for the kernel only, we
+ * should rather let it stay under the hood.
+ */
+
ret = skb->len;
netlink_skb_set_owner_r(skb, sk);
NETLINK_CB(skb).sk = ssk;
@@ -2096,7 +2245,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
if (len > sk->sk_sndbuf - 32)
goto out;
err = -ENOBUFS;
- skb = alloc_skb(len, GFP_KERNEL);
+ skb = netlink_alloc_large_skb(len, dst_group);
if (skb == NULL)
goto out;
@@ -2285,6 +2434,8 @@ __netlink_kernel_create(struct net *net, int unit, struct module *module,
if (cfg) {
nl_table[unit].bind = cfg->bind;
nl_table[unit].flags = cfg->flags;
+ if (cfg->compare)
+ nl_table[unit].compare = cfg->compare;
}
nl_table[unit].registered = 1;
} else {
@@ -2707,6 +2858,7 @@ static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct sock *s;
struct nl_seq_iter *iter;
+ struct net *net;
int i, j;
++*pos;
@@ -2714,11 +2866,12 @@ static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
if (v == SEQ_START_TOKEN)
return netlink_seq_socket_idx(seq, 0);
+ net = seq_file_net(seq);
iter = seq->private;
s = v;
do {
s = sk_next(s);
- } while (s && sock_net(s) != seq_file_net(seq));
+ } while (s && !nl_table[s->sk_protocol].compare(net, s));
if (s)
return s;
@@ -2730,7 +2883,8 @@ static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
for (; j <= hash->mask; j++) {
s = sk_head(&hash->table[j]);
- while (s && sock_net(s) != seq_file_net(seq))
+
+ while (s && !nl_table[s->sk_protocol].compare(net, s))
s = sk_next(s);
if (s) {
iter->link = i;
@@ -2923,8 +3077,12 @@ static int __init netlink_proto_init(void)
hash->shift = 0;
hash->mask = 0;
hash->rehash_time = jiffies;
+
+ nl_table[i].compare = netlink_compare;
}
+ INIT_LIST_HEAD(&netlink_tap_all);
+
netlink_add_usersock_entry();
sock_register(&netlink_family_ops);
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