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Miller" , Eric Dumazet , Gerrit Renker , Jakub Kicinski , Lorenz Bauer Subject: [PATCH bpf-next 01/17] flow_dissector: Extract attach/detach/query helpers Date: Wed, 6 May 2020 14:54:57 +0200 Message-Id: <20200506125514.1020829-2-jakub@cloudflare.com> X-Mailer: git-send-email 2.25.3 In-Reply-To: <20200506125514.1020829-1-jakub@cloudflare.com> References: <20200506125514.1020829-1-jakub@cloudflare.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org 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 Signed-off-by: Jakub Sitnicki --- 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