[linux-2.6-block.git] / net / ipv4 / udp_bpf.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Cloudflare Ltd https://cloudflare.com */

#include <linux/skmsg.h>
#include <net/sock.h>
#include <net/udp.h>

enum {
	UDP_BPF_IPV4,
	UDP_BPF_IPV6,
	UDP_BPF_NUM_PROTS,
};

static struct proto *udpv6_prot_saved __read_mostly;
static DEFINE_SPINLOCK(udpv6_prot_lock);
static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS];

static void udp_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
{
	*prot        = *base;
	prot->unhash = sock_map_unhash;
	prot->close  = sock_map_close;
}

static void udp_bpf_check_v6_needs_rebuild(struct proto *ops)
{
	if (unlikely(ops != smp_load_acquire(&udpv6_prot_saved))) {
		spin_lock_bh(&udpv6_prot_lock);
		if (likely(ops != udpv6_prot_saved)) {
			udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV6], ops);
			smp_store_release(&udpv6_prot_saved, ops);
		}
		spin_unlock_bh(&udpv6_prot_lock);
	}
}

static int __init udp_bpf_v4_build_proto(void)
{
	udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot);
	return 0;
}
core_initcall(udp_bpf_v4_build_proto);

int udp_bpf_update_proto(struct sock *sk, bool restore)
{
	int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
	struct sk_psock *psock = sk_psock(sk);

	if (restore) {
		sk->sk_write_space = psock->saved_write_space;
		/* Pairs with lockless read in sk_clone_lock() */
		WRITE_ONCE(sk->sk_prot, psock->sk_proto);
		return 0;
	}

	if (sk->sk_family == AF_INET6)
		udp_bpf_check_v6_needs_rebuild(psock->sk_proto);

	/* Pairs with lockless read in sk_clone_lock() */
	WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]);
	return 0;
}
EXPORT_SYMBOL_GPL(udp_bpf_update_proto);
Commit	Line	Data
edc6741c LB	1	// SPDX-License-Identifier: GPL-2.0
	2	/* Copyright (c) 2020 Cloudflare Ltd https://cloudflare.com */
	3
	4	#include <linux/skmsg.h>
	5	#include <net/sock.h>
	6	#include <net/udp.h>
	7
	8	enum {
	9	UDP_BPF_IPV4,
	10	UDP_BPF_IPV6,
	11	UDP_BPF_NUM_PROTS,
	12	};
	13
	14	static struct proto *udpv6_prot_saved __read_mostly;
	15	static DEFINE_SPINLOCK(udpv6_prot_lock);
	16	static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS];
	17
	18	static void udp_bpf_rebuild_protos(struct proto prot, const struct proto base)
	19	{
	20	prot = base;
	21	prot->unhash = sock_map_unhash;
	22	prot->close = sock_map_close;
	23	}
	24
7b219da4	25	static void udp_bpf_check_v6_needs_rebuild(struct proto *ops)
edc6741c	26	{
7b219da4	27	if (unlikely(ops != smp_load_acquire(&udpv6_prot_saved))) {
edc6741c LB	28	spin_lock_bh(&udpv6_prot_lock);
	29	if (likely(ops != udpv6_prot_saved)) {
	30	udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV6], ops);
	31	smp_store_release(&udpv6_prot_saved, ops);
	32	}
	33	spin_unlock_bh(&udpv6_prot_lock);
	34	}
	35	}
	36
	37	static int __init udp_bpf_v4_build_proto(void)
	38	{
	39	udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot);
	40	return 0;
	41	}
	42	core_initcall(udp_bpf_v4_build_proto);
	43
8a59f9d1	44	int udp_bpf_update_proto(struct sock *sk, bool restore)
edc6741c LB	45	{
edc6741c LB	46	int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
8a59f9d1 CW	47	struct sk_psock *psock = sk_psock(sk);
	48
	49	if (restore) {
	50	sk->sk_write_space = psock->saved_write_space;
	51	/* Pairs with lockless read in sk_clone_lock() */
	52	WRITE_ONCE(sk->sk_prot, psock->sk_proto);
	53	return 0;
	54	}
edc6741c	55
7b219da4 LB	56	if (sk->sk_family == AF_INET6)
7b219da4 LB	57	udp_bpf_check_v6_needs_rebuild(psock->sk_proto);
edc6741c	58
8a59f9d1 CW	59	/* Pairs with lockless read in sk_clone_lock() */
	60	WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]);
	61	return 0;
edc6741c	62	}
8a59f9d1	63	EXPORT_SYMBOL_GPL(udp_bpf_update_proto);