diff options
author | Jakub Sitnicki <jakub@cloudflare.com> | 2020-05-31 10:28:37 +0200 |
---|---|---|
committer | Alexei Starovoitov <ast@kernel.org> | 2020-06-02 00:21:02 +0200 |
commit | b27f7bb590ba835b32ef122389db158e44cfda1e (patch) | |
tree | 79716052834fb939fcb957d357f0b9213c9cb5fc /kernel/bpf | |
parent | net: Introduce netns_bpf for BPF programs attached to netns (diff) | |
download | linux-b27f7bb590ba835b32ef122389db158e44cfda1e.tar.xz linux-b27f7bb590ba835b32ef122389db158e44cfda1e.zip |
flow_dissector: Move out netns_bpf prog callbacks
Move functions to manage BPF programs attached to netns that are not
specific to flow dissector to a dedicated module named
bpf/net_namespace.c.
The set of functions will grow with the addition of bpf_link support for
netns attached programs. This patch prepares ground by creating a place
for it.
This is a code move with no functional changes intended.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200531082846.2117903-4-jakub@cloudflare.com
Diffstat (limited to 'kernel/bpf')
-rw-r--r-- | kernel/bpf/Makefile | 1 | ||||
-rw-r--r-- | kernel/bpf/net_namespace.c | 133 |
2 files changed, 134 insertions, 0 deletions
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 8fca02f64811..1131a921e1a6 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -13,6 +13,7 @@ ifeq ($(CONFIG_NET),y) obj-$(CONFIG_BPF_SYSCALL) += devmap.o obj-$(CONFIG_BPF_SYSCALL) += cpumap.o obj-$(CONFIG_BPF_SYSCALL) += offload.o +obj-$(CONFIG_BPF_SYSCALL) += net_namespace.o endif ifeq ($(CONFIG_PERF_EVENTS),y) obj-$(CONFIG_BPF_SYSCALL) += stackmap.o diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c new file mode 100644 index 000000000000..b37d81450c3a --- /dev/null +++ b/kernel/bpf/net_namespace.c @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/bpf.h> +#include <linux/filter.h> +#include <net/net_namespace.h> + +/* + * Functions to manage BPF programs attached to netns + */ + +/* Protects updates to netns_bpf */ +DEFINE_MUTEX(netns_bpf_mutex); + +int netns_bpf_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; + enum netns_bpf_attach_type type; + struct bpf_prog *attached; + struct net *net; + + if (attr->query.query_flags) + return -EINVAL; + + type = to_netns_bpf_attach_type(attr->query.attach_type); + if (type < 0) + return -EINVAL; + + 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->bpf.progs[type]); + if (attached) { + prog_cnt = 1; + prog_id = attached->aux->id; + } + rcu_read_unlock(); + + 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; +} + +int netns_bpf_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + enum netns_bpf_attach_type type; + struct net *net; + int ret; + + type = to_netns_bpf_attach_type(attr->attach_type); + if (type < 0) + return -EINVAL; + + net = current->nsproxy->net_ns; + mutex_lock(&netns_bpf_mutex); + switch (type) { + case NETNS_BPF_FLOW_DISSECTOR: + ret = flow_dissector_bpf_prog_attach(net, prog); + break; + default: + ret = -EINVAL; + break; + } + mutex_unlock(&netns_bpf_mutex); + + return ret; +} + +/* Must be called with netns_bpf_mutex held. */ +static int __netns_bpf_prog_detach(struct net *net, + enum netns_bpf_attach_type type) +{ + struct bpf_prog *attached; + + attached = rcu_dereference_protected(net->bpf.progs[type], + lockdep_is_held(&netns_bpf_mutex)); + if (!attached) + return -ENOENT; + RCU_INIT_POINTER(net->bpf.progs[type], NULL); + bpf_prog_put(attached); + return 0; +} + +int netns_bpf_prog_detach(const union bpf_attr *attr) +{ + enum netns_bpf_attach_type type; + int ret; + + type = to_netns_bpf_attach_type(attr->attach_type); + if (type < 0) + return -EINVAL; + + mutex_lock(&netns_bpf_mutex); + ret = __netns_bpf_prog_detach(current->nsproxy->net_ns, type); + mutex_unlock(&netns_bpf_mutex); + + return ret; +} + +static void __net_exit netns_bpf_pernet_pre_exit(struct net *net) +{ + enum netns_bpf_attach_type type; + + mutex_lock(&netns_bpf_mutex); + for (type = 0; type < MAX_NETNS_BPF_ATTACH_TYPE; type++) + __netns_bpf_prog_detach(net, type); + mutex_unlock(&netns_bpf_mutex); +} + +static struct pernet_operations netns_bpf_pernet_ops __net_initdata = { + .pre_exit = netns_bpf_pernet_pre_exit, +}; + +static int __init netns_bpf_init(void) +{ + return register_pernet_subsys(&netns_bpf_pernet_ops); +} + +subsys_initcall(netns_bpf_init); |