Commit 9e83f54f authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'bpf: expose bpf_{s,g}etsockopt helpers to bind{4,6} hooks' 



Stanislav Fomichev says:

====================

This might be useful for the listener sockets to pre-populate
some options. Since those helpers require locked sockets,
I'm changing bind hooks to lock/unlock the sockets. This
should not cause any performance overhead because at this
point there shouldn't be any socket lock contention and the
locking/unlocking should be cheap.

Also, as part of the series, I convert test_sock_addr bpf
assembly into C (and preserve the narrow load tests) to
make it easier to extend with th bpf_setsockopt later on.

v2:
* remove version from bpf programs (Andrii Nakryiko)
====================

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents ba058174 a540c81a

include/linux/bpf-cgroup.h

+6 −6
Original line number Diff line number Diff line
@@ -246,11 +246,11 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key, 
	__ret;								       \

})



#define BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr)			       \

	BPF_CGROUP_RUN_SA_PROG(sk, uaddr, BPF_CGROUP_INET4_BIND)

#define BPF_CGROUP_RUN_PROG_INET4_BIND_LOCK(sk, uaddr)			       \

	BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_INET4_BIND, NULL)



#define BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr)			       \

	BPF_CGROUP_RUN_SA_PROG(sk, uaddr, BPF_CGROUP_INET6_BIND)

#define BPF_CGROUP_RUN_PROG_INET6_BIND_LOCK(sk, uaddr)			       \

	BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_INET6_BIND, NULL)



#define BPF_CGROUP_PRE_CONNECT_ENABLED(sk) (cgroup_bpf_enabled && \

					    sk->sk_prot->pre_connect)
@@ -434,8 +434,8 @@ static inline int bpf_percpu_cgroup_storage_update(struct bpf_map *map, 
#define BPF_CGROUP_RUN_PROG_INET_EGRESS(sk,skb) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET4_BIND_LOCK(sk, uaddr) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET6_BIND_LOCK(sk, uaddr) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr) ({ 0; })

net/core/filter.c

+4 −0
Original line number Diff line number Diff line
@@ -6995,6 +6995,8 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
		return &bpf_sk_storage_delete_proto;

	case BPF_FUNC_setsockopt:

		switch (prog->expected_attach_type) {

		case BPF_CGROUP_INET4_BIND:

		case BPF_CGROUP_INET6_BIND:

		case BPF_CGROUP_INET4_CONNECT:

		case BPF_CGROUP_INET6_CONNECT:

			return &bpf_sock_addr_setsockopt_proto;
@@ -7003,6 +7005,8 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
		}

	case BPF_FUNC_getsockopt:

		switch (prog->expected_attach_type) {

		case BPF_CGROUP_INET4_BIND:

		case BPF_CGROUP_INET6_BIND:

		case BPF_CGROUP_INET4_CONNECT:

		case BPF_CGROUP_INET6_CONNECT:

			return &bpf_sock_addr_getsockopt_proto;

net/ipv4/af_inet.c

+1 −1
Original line number Diff line number Diff line
@@ -450,7 +450,7 @@ int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 
	/* BPF prog is run before any checks are done so that if the prog

	 * changes context in a wrong way it will be caught.

	 */

	err = BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr);

	err = BPF_CGROUP_RUN_PROG_INET4_BIND_LOCK(sk, uaddr);

	if (err)

		return err;

net/ipv6/af_inet6.c

+1 −1
Original line number Diff line number Diff line
@@ -451,7 +451,7 @@ int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 
	/* BPF prog is run before any checks are done so that if the prog

	 * changes context in a wrong way it will be caught.

	 */

	err = BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr);

	err = BPF_CGROUP_RUN_PROG_INET6_BIND_LOCK(sk, uaddr);

	if (err)

		return err;

tools/testing/selftests/bpf/progs/bind4_prog.c

0 → 100644
+102 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include <string.h>



#include <linux/stddef.h>

#include <linux/bpf.h>

#include <linux/in.h>

#include <linux/in6.h>

#include <sys/socket.h>

#include <netinet/tcp.h>

#include <linux/if.h>

#include <errno.h>



#include <bpf/bpf_helpers.h>

#include <bpf/bpf_endian.h>



#define SERV4_IP		0xc0a801feU /* 192.168.1.254 */

#define SERV4_PORT		4040

#define SERV4_REWRITE_IP	0x7f000001U /* 127.0.0.1 */

#define SERV4_REWRITE_PORT	4444



#ifndef IFNAMSIZ

#define IFNAMSIZ 16

#endif



static __inline int bind_to_device(struct bpf_sock_addr *ctx)

{

	char veth1[IFNAMSIZ] = "test_sock_addr1";

	char veth2[IFNAMSIZ] = "test_sock_addr2";

	char missing[IFNAMSIZ] = "nonexistent_dev";

	char del_bind[IFNAMSIZ] = "";



	if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,

				&veth1, sizeof(veth1)))

		return 1;

	if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,

				&veth2, sizeof(veth2)))

		return 1;

	if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,

				&missing, sizeof(missing)) != -ENODEV)

		return 1;

	if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,

				&del_bind, sizeof(del_bind)))

		return 1;



	return 0;

}



SEC("cgroup/bind4")

int bind_v4_prog(struct bpf_sock_addr *ctx)

{

	struct bpf_sock *sk;

	__u32 user_ip4;

	__u16 user_port;



	sk = ctx->sk;

	if (!sk)

		return 0;



	if (sk->family != AF_INET)

		return 0;



	if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)

		return 0;



	if (ctx->user_ip4 != bpf_htonl(SERV4_IP) ||

	    ctx->user_port != bpf_htons(SERV4_PORT))

		return 0;



	// u8 narrow loads:

	user_ip4 = 0;

	user_ip4 |= ((volatile __u8 *)&ctx->user_ip4)[0] << 0;

	user_ip4 |= ((volatile __u8 *)&ctx->user_ip4)[1] << 8;

	user_ip4 |= ((volatile __u8 *)&ctx->user_ip4)[2] << 16;

	user_ip4 |= ((volatile __u8 *)&ctx->user_ip4)[3] << 24;

	if (ctx->user_ip4 != user_ip4)

		return 0;



	user_port = 0;

	user_port |= ((volatile __u8 *)&ctx->user_port)[0] << 0;

	user_port |= ((volatile __u8 *)&ctx->user_port)[1] << 8;

	if (ctx->user_port != user_port)

		return 0;



	// u16 narrow loads:

	user_ip4 = 0;

	user_ip4 |= ((volatile __u16 *)&ctx->user_ip4)[0] << 0;

	user_ip4 |= ((volatile __u16 *)&ctx->user_ip4)[1] << 16;

	if (ctx->user_ip4 != user_ip4)

		return 0;



	/* Bind to device and unbind it. */

	if (bind_to_device(ctx))

		return 0;



	ctx->user_ip4 = bpf_htonl(SERV4_REWRITE_IP);

	ctx->user_port = bpf_htons(SERV4_REWRITE_PORT);



	return 1;

}



char _license[] SEC("license") = "GPL";

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