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.c168
1 files changed, 130 insertions, 38 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 1f15821c8da4..5681ce3aebca 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -62,6 +62,7 @@
#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 */
@@ -314,10 +315,12 @@ netlink_update_listeners(struct sock *sk)
unsigned long mask;
unsigned int i;
- for (i = 0; i < NLGRPSZ(tbl->groups)/sizeof(unsigned long); i++) {
+ for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
mask = 0;
- sk_for_each_bound(sk, node, &tbl->mc_list)
- mask |= nlk_sk(sk)->groups[i];
+ sk_for_each_bound(sk, node, &tbl->mc_list) {
+ if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
+ mask |= nlk_sk(sk)->groups[i];
+ }
tbl->listeners[i] = mask;
}
/* this function is only called with the netlink table "grabbed", which
@@ -555,26 +558,37 @@ netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
nlk->subscriptions = subscriptions;
}
-static int netlink_alloc_groups(struct sock *sk)
+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_lock_table();
+ netlink_table_grab();
+
groups = nl_table[sk->sk_protocol].groups;
- if (!nl_table[sk->sk_protocol].registered)
+ if (!nl_table[sk->sk_protocol].registered) {
err = -ENOENT;
- netlink_unlock_table();
+ goto out_unlock;
+ }
- if (err)
- return err;
+ if (nlk->ngroups >= groups)
+ goto out_unlock;
- nlk->groups = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
- if (nlk->groups == NULL)
- return -ENOMEM;
+ 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;
- return 0;
+ out_unlock:
+ netlink_table_ungrab();
+ return err;
}
static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
@@ -591,11 +605,9 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len
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;
- }
+ err = netlink_realloc_groups(sk);
+ if (err)
+ return err;
}
if (nlk->pid) {
@@ -839,10 +851,18 @@ retry:
int netlink_has_listeners(struct sock *sk, unsigned int group)
{
int res = 0;
+ unsigned long *listeners;
BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET));
+
+ 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, nl_table[sk->sk_protocol].listeners);
+ res = test_bit(group - 1, listeners);
+
+ rcu_read_unlock();
+
return res;
}
EXPORT_SYMBOL_GPL(netlink_has_listeners);
@@ -1007,18 +1027,36 @@ void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
read_unlock(&nl_table_lock);
}
+/* 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, int optlen)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
- int val = 0, err;
+ unsigned int val = 0;
+ int err;
if (level != SOL_NETLINK)
return -ENOPROTOOPT;
if (optlen >= sizeof(int) &&
- get_user(val, (int __user *)optval))
+ get_user(val, (unsigned int __user *)optval))
return -EFAULT;
switch (optname) {
@@ -1031,27 +1069,16 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname,
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;
- }
+ err = netlink_realloc_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_update_listeners(sk);
+ netlink_update_socket_mc(nlk, val,
+ optname == NETLINK_ADD_MEMBERSHIP);
netlink_table_ungrab();
err = 0;
break;
@@ -1327,6 +1354,71 @@ out_sock_release:
return NULL;
}
+/**
+ * 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)
+{
+ unsigned long *listeners, *old = NULL;
+ struct netlink_table *tbl = &nl_table[sk->sk_protocol];
+ int err = 0;
+
+ if (groups < 32)
+ groups = 32;
+
+ netlink_table_grab();
+ if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
+ listeners = kzalloc(NLGRPSZ(groups), GFP_ATOMIC);
+ if (!listeners) {
+ err = -ENOMEM;
+ goto out_ungrab;
+ }
+ old = tbl->listeners;
+ memcpy(listeners, old, NLGRPSZ(tbl->groups));
+ rcu_assign_pointer(tbl->listeners, listeners);
+ }
+ tbl->groups = groups;
+
+ out_ungrab:
+ netlink_table_ungrab();
+ synchronize_rcu();
+ kfree(old);
+ return err;
+}
+EXPORT_SYMBOL(netlink_change_ngroups);
+
+/**
+ * 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)
+{
+ struct sock *sk;
+ struct hlist_node *node;
+ struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
+
+ netlink_table_grab();
+
+ sk_for_each_bound(sk, node, &tbl->mc_list)
+ netlink_update_socket_mc(nlk_sk(sk), group, 0);
+
+ netlink_table_ungrab();
+}
+EXPORT_SYMBOL(netlink_clear_multicast_users);
+
void netlink_set_nonroot(int protocol, unsigned int flags)
{
if ((unsigned int)protocol < MAX_LINKS)
@@ -1713,7 +1805,7 @@ static int netlink_seq_show(struct seq_file *seq, void *v)
return 0;
}
-static struct seq_operations netlink_seq_ops = {
+static const struct seq_operations netlink_seq_ops = {
.start = netlink_seq_start,
.next = netlink_seq_next,
.stop = netlink_seq_stop,
generated by cgit v1.2.3 (git 2.0.4) at 2024-05-23 14:13:39 +0000