Commit b27f7bb5 authored by Jakub Sitnicki's avatar Jakub Sitnicki Committed by Alexei Starovoitov
Browse files

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: default avatarJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200531082846.2117903-4-jakub@cloudflare.com
parent a3fd7cee

include/net/flow_dissector.h

+6 −0
Original line number Diff line number Diff line
@@ -8,6 +8,8 @@ 
#include <linux/string.h>

#include <uapi/linux/if_ether.h>



struct bpf_prog;

struct net;

struct sk_buff;



/**
@@ -369,4 +371,8 @@ flow_dissector_init_keys(struct flow_dissector_key_control *key_control, 
	memset(key_basic, 0, sizeof(*key_basic));

}



#ifdef CONFIG_BPF_SYSCALL

int flow_dissector_bpf_prog_attach(struct net *net, struct bpf_prog *prog);

#endif /* CONFIG_BPF_SYSCALL */



#endif

kernel/bpf/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

kernel/bpf/net_namespace.c

0 → 100644
+133 −0
Original line number Diff line number Diff line 
// 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);

net/core/flow_dissector.c

+4 −121
Original line number Diff line number Diff line
@@ -33,9 +33,6 @@ 
#endif

#include <linux/bpf-netns.h>



/* Protects updates to netns_bpf */

DEFINE_MUTEX(netns_bpf_mutex);



static void dissector_set_key(struct flow_dissector *flow_dissector,

			      enum flow_dissector_key_id key_id)

{
@@ -72,52 +69,8 @@ void skb_flow_dissector_init(struct flow_dissector *flow_dissector, 
}

EXPORT_SYMBOL(skb_flow_dissector_init);



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;

}



static int flow_dissector_bpf_prog_attach(struct net *net,

					  struct bpf_prog *prog)

#ifdef CONFIG_BPF_SYSCALL

int flow_dissector_bpf_prog_attach(struct net *net, struct bpf_prog *prog)

{

	enum netns_bpf_attach_type type = NETNS_BPF_FLOW_DISSECTOR;

	struct bpf_prog *attached;
@@ -155,76 +108,7 @@ static int flow_dissector_bpf_prog_attach(struct net *net, 
		bpf_prog_put(attached);

	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,

};

#endif /* CONFIG_BPF_SYSCALL */



/**

 * __skb_flow_get_ports - extract the upper layer ports and return them
@@ -1902,7 +1786,6 @@ static int __init init_default_flow_dissectors(void) 
	skb_flow_dissector_init(&flow_keys_basic_dissector,

				flow_keys_basic_dissector_keys,

				ARRAY_SIZE(flow_keys_basic_dissector_keys));



	return register_pernet_subsys(&netns_bpf_pernet_ops);

	return 0;

}

core_initcall(init_default_flow_dissectors);

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