[RFCv2 bpf-next 01/12] flow_dissector: Extract attach/detach/query helpers
From: Jakub Sitnicki <jakub@cloudflare.com>
Date: 2019-08-28 07:23:00
Also in:
bpf
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 <redacted> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> --- include/linux/bpf.h | 8 +++++ net/core/filter.c | 73 +++++++++++++++++++++++++++++++++++++++ net/core/flow_dissector.c | 65 ++++++---------------------------- 3 files changed, 92 insertions(+), 54 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 5b9d22338606..b301e0c03a8c 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h@@ -23,6 +23,7 @@ struct sock; struct seq_file; struct btf; struct btf_type; +struct mutex; extern struct idr btf_idr; extern spinlock_t btf_idr_lock;
@@ -1145,4 +1146,11 @@ static inline u32 bpf_xdp_sock_convert_ctx_access(enum bpf_access_type type, } #endif /* CONFIG_INET */ +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 0c1059cdad3d..a498fbaa2d50 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -8668,6 +8668,79 @@ 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; + + mutex_lock(lock); + attached = rcu_dereference_protected(*pprog, + lockdep_is_held(lock)); + if (attached) { + /* Only one BPF program can be attached at a time */ + mutex_unlock(lock); + return -EEXIST; + } + rcu_assign_pointer(*pprog, prog); + mutex_unlock(lock); + + return 0; +} + +int bpf_prog_detach_one(struct bpf_prog __rcu **pprog, struct mutex *lock) +{ + struct bpf_prog *attached; + + mutex_lock(lock); + attached = rcu_dereference_protected(*pprog, + lockdep_is_held(lock)); + if (!attached) { + mutex_unlock(lock); + return -ENOENT; + } + RCU_INIT_POINTER(*pprog, NULL); + bpf_prog_put(attached); + mutex_unlock(lock); + + return 0; +} + #ifdef CONFIG_INET struct sk_reuseport_kern { struct sk_buff *skb;
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 9741b593ea53..c51602158906 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c@@ -73,80 +73,37 @@ 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; + struct net *net = current->nsproxy->net_ns; - 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) { - /* Only one BPF program can be attached at a time */ - mutex_unlock(&flow_dissector_mutex); - return -EEXIST; - } - rcu_assign_pointer(net->flow_dissector_prog, prog); - mutex_unlock(&flow_dissector_mutex); - return 0; + return bpf_prog_attach_one(&net->flow_dissector_prog, + &flow_dissector_mutex, prog, + attr->attach_flags); } 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; - 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; - } - bpf_prog_put(attached); - RCU_INIT_POINTER(net->flow_dissector_prog, NULL); - mutex_unlock(&flow_dissector_mutex); - return 0; + return bpf_prog_detach_one(&net->flow_dissector_prog, + &flow_dissector_mutex); } + /** * skb_flow_get_be16 - extract be16 entity * @skb: sk_buff to extract from
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2.20.1