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Message-Id: <20200506125514.1020829-2-jakub@cloudflare.com>
Date: Wed, 6 May 2020 14:54:57 +0200
From: Jakub Sitnicki <jakub@...udflare.com>
To: netdev@...r.kernel.org, bpf@...r.kernel.org
Cc: dccp@...r.kernel.org, kernel-team@...udflare.com,
Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Gerrit Renker <gerrit@....abdn.ac.uk>,
Jakub Kicinski <kuba@...nel.org>,
Lorenz Bauer <lmb@...udflare.com>
Subject: [PATCH bpf-next 01/17] flow_dissector: Extract attach/detach/query helpers
Move generic parts of callbacks for querying, attaching, and detaching a
single BPF program for reuse by other BPF program types.
Subsequent patch makes use of the extracted routines.
Reviewed-by: Lorenz Bauer <lmb@...udflare.com>
Signed-off-by: Jakub Sitnicki <jakub@...udflare.com>
---
include/linux/bpf.h | 8 +++++
net/core/filter.c | 68 +++++++++++++++++++++++++++++++++++++++
net/core/flow_dissector.c | 61 +++++++----------------------------
3 files changed, 88 insertions(+), 49 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 1262ec460ab3..716c47ac1e75 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -31,6 +31,7 @@ struct seq_file;
struct btf;
struct btf_type;
struct exception_table_entry;
+struct mutex;
extern struct idr btf_idr;
extern spinlock_t btf_idr_lock;
@@ -1660,4 +1661,11 @@ enum bpf_text_poke_type {
int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
void *addr1, void *addr2);
+int bpf_prog_query_one(struct bpf_prog __rcu **pprog,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr);
+int bpf_prog_attach_one(struct bpf_prog __rcu **pprog, struct mutex *lock,
+ struct bpf_prog *prog, u32 flags);
+int bpf_prog_detach_one(struct bpf_prog __rcu **pprog, struct mutex *lock);
+
#endif /* _LINUX_BPF_H */
diff --git a/net/core/filter.c b/net/core/filter.c
index dfaf5df13722..bc25bb1085b1 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8740,6 +8740,74 @@ int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf,
return ret;
}
+int bpf_prog_query_one(struct bpf_prog __rcu **pprog,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+ u32 prog_id, prog_cnt = 0, flags = 0;
+ struct bpf_prog *attached;
+
+ if (attr->query.query_flags)
+ return -EINVAL;
+
+ rcu_read_lock();
+ attached = rcu_dereference(*pprog);
+ if (attached) {
+ prog_cnt = 1;
+ prog_id = attached->aux->id;
+ }
+ rcu_read_unlock();
+
+ if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
+ return -EFAULT;
+ if (copy_to_user(&uattr->query.prog_cnt, &prog_cnt, sizeof(prog_cnt)))
+ return -EFAULT;
+
+ if (!attr->query.prog_cnt || !prog_ids || !prog_cnt)
+ return 0;
+
+ if (copy_to_user(prog_ids, &prog_id, sizeof(u32)))
+ return -EFAULT;
+
+ return 0;
+}
+
+int bpf_prog_attach_one(struct bpf_prog __rcu **pprog, struct mutex *lock,
+ struct bpf_prog *prog, u32 flags)
+{
+ struct bpf_prog *attached;
+
+ if (flags)
+ return -EINVAL;
+
+ attached = rcu_dereference_protected(*pprog,
+ lockdep_is_held(lock));
+ if (attached == prog) {
+ /* The same program cannot be attached twice */
+ return -EINVAL;
+ }
+ rcu_assign_pointer(*pprog, prog);
+ if (attached)
+ bpf_prog_put(attached);
+
+ return 0;
+}
+
+int bpf_prog_detach_one(struct bpf_prog __rcu **pprog, struct mutex *lock)
+{
+ struct bpf_prog *attached;
+
+ attached = rcu_dereference_protected(*pprog,
+ lockdep_is_held(lock));
+ if (!attached)
+ return -ENOENT;
+ RCU_INIT_POINTER(*pprog, NULL);
+ bpf_prog_put(attached);
+
+ return 0;
+}
+
#ifdef CONFIG_INET
static void bpf_init_reuseport_kern(struct sk_reuseport_kern *reuse_kern,
struct sock_reuseport *reuse,
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 3eff84824c8b..5ff99ed175bd 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -73,46 +73,22 @@ EXPORT_SYMBOL(skb_flow_dissector_init);
int skb_flow_dissector_prog_query(const union bpf_attr *attr,
union bpf_attr __user *uattr)
{
- __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
- u32 prog_id, prog_cnt = 0, flags = 0;
- struct bpf_prog *attached;
struct net *net;
-
- if (attr->query.query_flags)
- return -EINVAL;
+ int ret;
net = get_net_ns_by_fd(attr->query.target_fd);
if (IS_ERR(net))
return PTR_ERR(net);
- rcu_read_lock();
- attached = rcu_dereference(net->flow_dissector_prog);
- if (attached) {
- prog_cnt = 1;
- prog_id = attached->aux->id;
- }
- rcu_read_unlock();
+ ret = bpf_prog_query_one(&net->flow_dissector_prog, attr, uattr);
put_net(net);
-
- if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
- return -EFAULT;
- if (copy_to_user(&uattr->query.prog_cnt, &prog_cnt, sizeof(prog_cnt)))
- return -EFAULT;
-
- if (!attr->query.prog_cnt || !prog_ids || !prog_cnt)
- return 0;
-
- if (copy_to_user(prog_ids, &prog_id, sizeof(u32)))
- return -EFAULT;
-
- return 0;
+ return ret;
}
int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
struct bpf_prog *prog)
{
- struct bpf_prog *attached;
struct net *net;
int ret = 0;
@@ -145,16 +121,9 @@ int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
}
}
- attached = rcu_dereference_protected(net->flow_dissector_prog,
- lockdep_is_held(&flow_dissector_mutex));
- if (attached == prog) {
- /* The same program cannot be attached twice */
- ret = -EINVAL;
- goto out;
- }
- rcu_assign_pointer(net->flow_dissector_prog, prog);
- if (attached)
- bpf_prog_put(attached);
+ ret = bpf_prog_attach_one(&net->flow_dissector_prog,
+ &flow_dissector_mutex, prog,
+ attr->attach_flags);
out:
mutex_unlock(&flow_dissector_mutex);
return ret;
@@ -162,21 +131,15 @@ int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr)
{
- struct bpf_prog *attached;
- struct net *net;
+ struct net *net = current->nsproxy->net_ns;
+ int ret;
- net = current->nsproxy->net_ns;
mutex_lock(&flow_dissector_mutex);
- attached = rcu_dereference_protected(net->flow_dissector_prog,
- lockdep_is_held(&flow_dissector_mutex));
- if (!attached) {
- mutex_unlock(&flow_dissector_mutex);
- return -ENOENT;
- }
- RCU_INIT_POINTER(net->flow_dissector_prog, NULL);
- bpf_prog_put(attached);
+ ret = bpf_prog_detach_one(&net->flow_dissector_prog,
+ &flow_dissector_mutex);
mutex_unlock(&flow_dissector_mutex);
- return 0;
+
+ return ret;
}
/**
--
2.25.3
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