@@ -153,6 +153,9 @@ static inline unsigned int sk_filter_len(const struct sk_filter *fp)
extern int sk_filter(struct sock *sk, struct sk_buff *skb);
extern unsigned int sk_run_filter(const struct sk_buff *skb,
const struct sock_filter *filter);
+extern int sk_unattached_filter_create(struct sk_filter **pfp,
+ struct sock_fprog *fprog);
+extern void sk_unattached_filter_destroy(struct sk_filter *fp);
extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
extern int sk_detach_filter(struct sock *sk);
extern int sk_chk_filter(struct sock_filter *filter, unsigned int flen);
@@ -587,6 +587,67 @@ void sk_filter_release_rcu(struct rcu_head *rcu)
}
EXPORT_SYMBOL(sk_filter_release_rcu);
+static int __sk_prepare_filter(struct sk_filter *fp)
+{
+ int err;
+
+ fp->bpf_func = sk_run_filter;
+
+ err = sk_chk_filter(fp->insns, fp->len);
+ if (err)
+ return err;
+
+ bpf_jit_compile(fp);
+ return 0;
+}
+
+/**
+ * sk_unattached_filter_create - create an unattached filter
+ * @fprog: the filter program
+ * @sk: the socket to use
+ *
+ * Create a filter independent ofr any socket. We first run some
+ * sanity checks on it to make sure it does not explode on us later.
+ * If an error occurs or there is insufficient memory for the filter
+ * a negative errno code is returned. On success the return is zero.
+ */
+int sk_unattached_filter_create(struct sk_filter **pfp,
+ struct sock_fprog *fprog)
+{
+ struct sk_filter *fp;
+ unsigned int fsize = sizeof(struct sock_filter) * fprog->len;
+ int err;
+
+ /* Make sure new filter is there and in the right amounts. */
+ if (fprog->filter == NULL)
+ return -EINVAL;
+
+ fp = kmalloc(fsize + sizeof(*fp), GFP_KERNEL);
+ if (!fp)
+ return -ENOMEM;
+ memcpy(fp->insns, fprog->filter, fsize);
+
+ atomic_set(&fp->refcnt, 1);
+ fp->len = fprog->len;
+
+ err = __sk_prepare_filter(fp);
+ if (err)
+ goto free_mem;
+
+ *pfp = fp;
+ return 0;
+free_mem:
+ kfree(fp);
+ return err;
+}
+EXPORT_SYMBOL_GPL(sk_unattached_filter_create);
+
+void sk_unattached_filter_destroy(struct sk_filter *fp)
+{
+ sk_filter_release(fp);
+}
+EXPORT_SYMBOL_GPL(sk_unattached_filter_destroy);
+
/**
* sk_attach_filter - attach a socket filter
* @fprog: the filter program
@@ -617,16 +678,13 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
atomic_set(&fp->refcnt, 1);
fp->len = fprog->len;
- fp->bpf_func = sk_run_filter;
- err = sk_chk_filter(fp->insns, fp->len);
+ err = __sk_prepare_filter(fp);
if (err) {
sk_filter_uncharge(sk, fp);
return err;
}
- bpf_jit_compile(fp);
-
old_fp = rcu_dereference_protected(sk->sk_filter,
sock_owned_by_user(sk));
rcu_assign_pointer(sk->sk_filter, fp);
Today, BPF filters are bind to sockets. Since BPF machine becomes handy for other purposes, this patch allows to create unattached filter. Signed-off-by: Jiri Pirko <jpirko@redhat.com> --- include/linux/filter.h | 3 ++ net/core/filter.c | 66 +++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 65 insertions(+), 4 deletions(-)