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Diffstat (limited to 'net/netlink/af_netlink.c')
-rw-r--r--net/netlink/af_netlink.c98
1 files changed, 64 insertions, 34 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index c48b0f49f00..42d2fb94eff 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -56,6 +56,7 @@
#include <linux/types.h>
#include <linux/audit.h>
#include <linux/selinux.h>
+#include <linux/mutex.h>
#include <net/sock.h>
#include <net/scm.h>
@@ -76,7 +77,8 @@ struct netlink_sock {
unsigned long state;
wait_queue_head_t wait;
struct netlink_callback *cb;
- spinlock_t cb_lock;
+ struct mutex *cb_mutex;
+ struct mutex cb_def_mutex;
void (*data_ready)(struct sock *sk, int bytes);
struct module *module;
};
@@ -108,6 +110,7 @@ struct netlink_table {
unsigned long *listeners;
unsigned int nl_nonroot;
unsigned int groups;
+ struct mutex *cb_mutex;
struct module *module;
int registered;
};
@@ -118,6 +121,7 @@ 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 void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb);
static DEFINE_RWLOCK(nl_table_lock);
static atomic_t nl_table_users = ATOMIC_INIT(0);
@@ -370,7 +374,8 @@ static struct proto netlink_proto = {
.obj_size = sizeof(struct netlink_sock),
};
-static int __netlink_create(struct socket *sock, int protocol)
+static int __netlink_create(struct socket *sock, struct mutex *cb_mutex,
+ int protocol)
{
struct sock *sk;
struct netlink_sock *nlk;
@@ -384,7 +389,12 @@ static int __netlink_create(struct socket *sock, int protocol)
sock_init_data(sock, sk);
nlk = nlk_sk(sk);
- spin_lock_init(&nlk->cb_lock);
+ 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;
@@ -395,8 +405,8 @@ static int __netlink_create(struct socket *sock, int protocol)
static int netlink_create(struct socket *sock, int protocol)
{
struct module *module = NULL;
+ struct mutex *cb_mutex;
struct netlink_sock *nlk;
- unsigned int groups;
int err = 0;
sock->state = SS_UNCONNECTED;
@@ -418,10 +428,10 @@ static int netlink_create(struct socket *sock, int protocol)
if (nl_table[protocol].registered &&
try_module_get(nl_table[protocol].module))
module = nl_table[protocol].module;
- groups = nl_table[protocol].groups;
+ cb_mutex = nl_table[protocol].cb_mutex;
netlink_unlock_table();
- if ((err = __netlink_create(sock, protocol)) < 0)
+ if ((err = __netlink_create(sock, cb_mutex, protocol)) < 0)
goto out_module;
nlk = nlk_sk(sock->sk);
@@ -446,14 +456,14 @@ static int netlink_release(struct socket *sock)
sock_orphan(sk);
nlk = nlk_sk(sk);
- spin_lock(&nlk->cb_lock);
+ mutex_lock(nlk->cb_mutex);
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);
+ mutex_unlock(nlk->cb_mutex);
/* OK. Socket is unlinked, and, therefore,
no new packets will arrive */
@@ -1215,7 +1225,7 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
copied = len;
}
- skb->h.raw = skb->data;
+ skb_reset_transport_header(skb);
err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
if (msg->msg_name) {
@@ -1242,6 +1252,9 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
scm_recv(sock, msg, siocb->scm, flags);
+ if (flags & MSG_TRUNC)
+ copied = skb->len;
+
out:
netlink_rcv_wake(sk);
return err ? : copied;
@@ -1265,7 +1278,7 @@ static void netlink_data_ready(struct sock *sk, int len)
struct sock *
netlink_kernel_create(int unit, unsigned int groups,
void (*input)(struct sock *sk, int len),
- struct module *module)
+ struct mutex *cb_mutex, struct module *module)
{
struct socket *sock;
struct sock *sk;
@@ -1280,7 +1293,7 @@ netlink_kernel_create(int unit, unsigned int groups,
if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
return NULL;
- if (__netlink_create(sock, unit) < 0)
+ if (__netlink_create(sock, cb_mutex, unit) < 0)
goto out_sock_release;
if (groups < 32)
@@ -1304,6 +1317,7 @@ netlink_kernel_create(int unit, unsigned int groups,
netlink_table_grab();
nl_table[unit].groups = groups;
nl_table[unit].listeners = listeners;
+ nl_table[unit].cb_mutex = cb_mutex;
nl_table[unit].module = module;
nl_table[unit].registered = 1;
netlink_table_ungrab();
@@ -1346,7 +1360,7 @@ static int netlink_dump(struct sock *sk)
if (!skb)
goto errout;
- spin_lock(&nlk->cb_lock);
+ mutex_lock(nlk->cb_mutex);
cb = nlk->cb;
if (cb == NULL) {
@@ -1357,7 +1371,7 @@ static int netlink_dump(struct sock *sk)
len = cb->dump(skb, cb);
if (len > 0) {
- spin_unlock(&nlk->cb_lock);
+ mutex_unlock(nlk->cb_mutex);
skb_queue_tail(&sk->sk_receive_queue, skb);
sk->sk_data_ready(sk, len);
return 0;
@@ -1375,13 +1389,13 @@ static int netlink_dump(struct sock *sk)
if (cb->done)
cb->done(cb);
nlk->cb = NULL;
- spin_unlock(&nlk->cb_lock);
+ mutex_unlock(nlk->cb_mutex);
netlink_destroy_callback(cb);
return 0;
errout_skb:
- spin_unlock(&nlk->cb_lock);
+ mutex_unlock(nlk->cb_mutex);
kfree_skb(skb);
errout:
return err;
@@ -1413,19 +1427,24 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
}
nlk = nlk_sk(sk);
/* A dump or destruction is in progress... */
- spin_lock(&nlk->cb_lock);
+ mutex_lock(nlk->cb_mutex);
if (nlk->cb || sock_flag(sk, SOCK_DEAD)) {
- spin_unlock(&nlk->cb_lock);
+ mutex_unlock(nlk->cb_mutex);
netlink_destroy_callback(cb);
sock_put(sk);
return -EBUSY;
}
nlk->cb = cb;
- spin_unlock(&nlk->cb_lock);
+ mutex_unlock(nlk->cb_mutex);
netlink_dump(sk);
sock_put(sk);
- return 0;
+
+ /* We successfully started a dump, by returning -EINTR we
+ * signal the queue mangement to interrupt processing of
+ * any netlink messages so userspace gets a chance to read
+ * the results. */
+ return -EINTR;
}
void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
@@ -1462,27 +1481,35 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
}
static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
- struct nlmsghdr *, int *))
+ struct nlmsghdr *))
{
struct nlmsghdr *nlh;
int err;
while (skb->len >= nlmsg_total_size(0)) {
- nlh = (struct nlmsghdr *) skb->data;
+ nlh = nlmsg_hdr(skb);
+ err = 0;
if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
return 0;
- 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;
+ /* Only requests are handled by the kernel */
+ if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
+ goto skip;
+
+ /* Skip control messages */
+ if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
+ goto skip;
+
+ err = cb(skb, nlh);
+ if (err == -EINTR) {
+ /* Not an error, but we interrupt processing */
+ netlink_queue_skip(nlh, skb);
+ return err;
+ }
+skip:
+ if (nlh->nlmsg_flags & NLM_F_ACK || err)
netlink_ack(skb, nlh, err);
- } else if (nlh->nlmsg_flags & NLM_F_ACK)
- netlink_ack(skb, nlh, 0);
netlink_queue_skip(nlh, skb);
}
@@ -1504,9 +1531,14 @@ static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
*
* qlen must be initialized to 0 before the initial entry, afterwards
* the function may be called repeatedly until qlen reaches 0.
+ *
+ * The callback function may return -EINTR to signal that processing
+ * of netlink messages shall be interrupted. In this case the message
+ * currently being processed will NOT be requeued onto the receive
+ * queue.
*/
void netlink_run_queue(struct sock *sk, unsigned int *qlen,
- int (*cb)(struct sk_buff *, struct nlmsghdr *, int *))
+ int (*cb)(struct sk_buff *, struct nlmsghdr *))
{
struct sk_buff *skb;
@@ -1537,7 +1569,7 @@ void netlink_run_queue(struct sock *sk, unsigned int *qlen,
* 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)
+static void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb)
{
int msglen = NLMSG_ALIGN(nlh->nlmsg_len);
@@ -1820,12 +1852,10 @@ 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);
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-03 17:27:50 +0000