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Commit cd86d1fd authored by Lawrence Brakmo's avatar Lawrence Brakmo Committed by David S. Miller
Browse files

bpf: Adding helper function bpf_getsockops 



Adding support for helper function bpf_getsockops to socket_ops BPF
programs. This patch only supports TCP_CONGESTION.

Signed-off-by: default avatarVlad Vysotsky <vlad@cs.ucla.edu>
Acked-by: default avatarLawrence Brakmo <brakmo@fb.com>
Acked-by: default avatarAlexei Starovoitov <ast@fb.com>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e6546ef6

include/uapi/linux/bpf.h

+15 −4
Original line number Diff line number Diff line
@@ -613,12 +613,22 @@ union bpf_attr { 
 * int bpf_setsockopt(bpf_socket, level, optname, optval, optlen)

 *     Calls setsockopt. Not all opts are available, only those with

 *     integer optvals plus TCP_CONGESTION.

 *     Supported levels: SOL_SOCKET and IPROTO_TCP

 *     Supported levels: SOL_SOCKET and IPPROTO_TCP

 *     @bpf_socket: pointer to bpf_socket

 *     @level: SOL_SOCKET or IPROTO_TCP

 *     @level: SOL_SOCKET or IPPROTO_TCP

 *     @optname: option name

 *     @optval: pointer to option value

 *     @optlen: length of optval in byes

 *     @optlen: length of optval in bytes

 *     Return: 0 or negative error

 *

 * int bpf_getsockopt(bpf_socket, level, optname, optval, optlen)

 *     Calls getsockopt. Not all opts are available.

 *     Supported levels: IPPROTO_TCP

 *     @bpf_socket: pointer to bpf_socket

 *     @level: IPPROTO_TCP

 *     @optname: option name

 *     @optval: pointer to option value

 *     @optlen: length of optval in bytes

 *     Return: 0 or negative error

 *

 * int bpf_skb_adjust_room(skb, len_diff, mode, flags)
@@ -721,7 +731,8 @@ union bpf_attr { 
	FN(sock_map_update),		\

	FN(xdp_adjust_meta),		\

	FN(perf_event_read_value),	\

	FN(perf_prog_read_value),

	FN(perf_prog_read_value),	\

	FN(getsockopt),



/* integer value in 'imm' field of BPF_CALL instruction selects which helper

 * function eBPF program intends to call

net/core/filter.c

+45 −1
Original line number Diff line number Diff line
@@ -3273,7 +3273,7 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock, 


static const struct bpf_func_proto bpf_setsockopt_proto = {

	.func		= bpf_setsockopt,

	.gpl_only	= true,

	.gpl_only	= false,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_CTX,

	.arg2_type	= ARG_ANYTHING,
@@ -3282,6 +3282,48 @@ static const struct bpf_func_proto bpf_setsockopt_proto = { 
	.arg5_type	= ARG_CONST_SIZE,

};



BPF_CALL_5(bpf_getsockopt, struct bpf_sock_ops_kern *, bpf_sock,

	   int, level, int, optname, char *, optval, int, optlen)

{

	struct sock *sk = bpf_sock->sk;

	int ret = 0;



	if (!sk_fullsock(sk))

		goto err_clear;



#ifdef CONFIG_INET

	if (level == SOL_TCP && sk->sk_prot->getsockopt == tcp_getsockopt) {

		if (optname == TCP_CONGESTION) {

			struct inet_connection_sock *icsk = inet_csk(sk);



			if (!icsk->icsk_ca_ops || optlen <= 1)

				goto err_clear;

			strncpy(optval, icsk->icsk_ca_ops->name, optlen);

			optval[optlen - 1] = 0;

		} else {

			goto err_clear;

		}

	} else {

		goto err_clear;

	}

	return ret;

#endif

err_clear:

	memset(optval, 0, optlen);

	return -EINVAL;

}



static const struct bpf_func_proto bpf_getsockopt_proto = {

	.func		= bpf_getsockopt,

	.gpl_only	= false,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_CTX,

	.arg2_type	= ARG_ANYTHING,

	.arg3_type	= ARG_ANYTHING,

	.arg4_type	= ARG_PTR_TO_UNINIT_MEM,

	.arg5_type	= ARG_CONST_SIZE,

};



static const struct bpf_func_proto *

bpf_base_func_proto(enum bpf_func_id func_id)

{
@@ -3460,6 +3502,8 @@ static const struct bpf_func_proto * 
	switch (func_id) {

	case BPF_FUNC_setsockopt:

		return &bpf_setsockopt_proto;

	case BPF_FUNC_getsockopt:

		return &bpf_getsockopt_proto;

	case BPF_FUNC_sock_map_update:

		return &bpf_sock_map_update_proto;

	default:

tools/testing/selftests/bpf/bpf_helpers.h

+3 −0
Original line number Diff line number Diff line
@@ -67,6 +67,9 @@ static int (*bpf_xdp_adjust_meta)(void *ctx, int offset) = 
static int (*bpf_setsockopt)(void *ctx, int level, int optname, void *optval,

			     int optlen) =

	(void *) BPF_FUNC_setsockopt;

static int (*bpf_getsockopt)(void *ctx, int level, int optname, void *optval,

			     int optlen) =

	(void *) BPF_FUNC_getsockopt;

static int (*bpf_sk_redirect_map)(void *map, int key, int flags) =

	(void *) BPF_FUNC_sk_redirect_map;

static int (*bpf_sock_map_update)(void *map, void *key, void *value,