else if (k >= SKF_LL_OFF)
ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
- if (ptr >= skb->head && ptr < skb->tail)
+ if (ptr >= skb->head && ptr < skb_tail_pointer(skb))
return ptr;
return NULL;
}
return 0;
}
+EXPORT_SYMBOL(sk_run_filter);
/**
* sk_chk_filter - verify socket filter code
return (BPF_CLASS(filter[flen - 1].code) == BPF_RET) ? 0 : -EINVAL;
}
+EXPORT_SYMBOL(sk_chk_filter);
+
+/**
+ * sk_filter_rcu_release: Release a socket filter by rcu_head
+ * @rcu: rcu_head that contains the sk_filter to free
+ */
+static void sk_filter_rcu_release(struct rcu_head *rcu)
+{
+ struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu);
+
+ sk_filter_release(fp);
+}
+
+static void sk_filter_delayed_uncharge(struct sock *sk, struct sk_filter *fp)
+{
+ unsigned int size = sk_filter_len(fp);
+
+ atomic_sub(size, &sk->sk_omem_alloc);
+ call_rcu_bh(&fp->rcu, sk_filter_rcu_release);
+}
/**
* sk_attach_filter - attach a socket filter
*/
int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
{
- struct sk_filter *fp;
+ struct sk_filter *fp, *old_fp;
unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
int err;
fp->len = fprog->len;
err = sk_chk_filter(fp->insns, fp->len);
- if (!err) {
- struct sk_filter *old_fp;
-
- rcu_read_lock_bh();
- old_fp = rcu_dereference(sk->sk_filter);
- rcu_assign_pointer(sk->sk_filter, fp);
- rcu_read_unlock_bh();
- fp = old_fp;
+ if (err) {
+ sk_filter_uncharge(sk, fp);
+ return err;
}
- if (fp)
- sk_filter_release(sk, fp);
- return err;
+ rcu_read_lock_bh();
+ old_fp = rcu_dereference(sk->sk_filter);
+ rcu_assign_pointer(sk->sk_filter, fp);
+ rcu_read_unlock_bh();
+
+ if (old_fp)
+ sk_filter_delayed_uncharge(sk, old_fp);
+ return 0;
}
-EXPORT_SYMBOL(sk_chk_filter);
-EXPORT_SYMBOL(sk_run_filter);
+int sk_detach_filter(struct sock *sk)
+{
+ int ret = -ENOENT;
+ struct sk_filter *filter;
+
+ rcu_read_lock_bh();
+ filter = rcu_dereference(sk->sk_filter);
+ if (filter) {
+ rcu_assign_pointer(sk->sk_filter, NULL);
+ sk_filter_delayed_uncharge(sk, filter);
+ ret = 0;
+ }
+ rcu_read_unlock_bh();
+ return ret;
+}