Commit 91b8270f authored by Chenbo Feng's avatar Chenbo Feng Committed by David S. Miller
Browse files

Add a helper function to get socket cookie in eBPF 



Retrieve the socket cookie generated by sock_gen_cookie() from a sk_buff
with a known socket. Generates a new cookie if one was not yet set.If
the socket pointer inside sk_buff is NULL, 0 is returned. The helper
function coud be useful in monitoring per socket networking traffic
statistics and provide a unique socket identifier per namespace.

Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarChenbo Feng <fengc@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 16ae1f22

include/linux/sock_diag.h

+1 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ void sock_diag_unregister(const struct sock_diag_handler *h); 
void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh));

void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh));



u64 sock_gen_cookie(struct sock *sk);

int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie);

void sock_diag_save_cookie(struct sock *sk, __u32 *cookie);

include/uapi/linux/bpf.h

+8 −1
Original line number Diff line number Diff line
@@ -459,6 +459,12 @@ union bpf_attr { 
 *     Return:

 *       > 0 length of the string including the trailing NUL on success

 *       < 0 error

 *

 * u64 bpf_bpf_get_socket_cookie(skb)

 *     Get the cookie for the socket stored inside sk_buff.

 *     @skb: pointer to skb

 *     Return: 8 Bytes non-decreasing number on success or 0 if the socket

 *     field is missing inside sk_buff

 */

#define __BPF_FUNC_MAPPER(FN)		\

	FN(unspec),			\
@@ -506,7 +512,8 @@ union bpf_attr { 
	FN(get_numa_node_id),		\

	FN(skb_change_head),		\

	FN(xdp_adjust_head),		\

	FN(probe_read_str),

	FN(probe_read_str),		\

	FN(get_socket_cookie),



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

 * function eBPF program intends to call

net/core/filter.c

+17 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/mm.h>

#include <linux/fcntl.h>

#include <linux/socket.h>

#include <linux/sock_diag.h>

#include <linux/in.h>

#include <linux/inet.h>

#include <linux/netdevice.h>
@@ -2606,6 +2607,18 @@ static const struct bpf_func_proto bpf_xdp_event_output_proto = { 
	.arg5_type	= ARG_CONST_SIZE,

};



BPF_CALL_1(bpf_get_socket_cookie, struct sk_buff *, skb)

{

	return skb->sk ? sock_gen_cookie(skb->sk) : 0;

}



static const struct bpf_func_proto bpf_get_socket_cookie_proto = {

	.func           = bpf_get_socket_cookie,

	.gpl_only       = false,

	.ret_type       = RET_INTEGER,

	.arg1_type      = ARG_PTR_TO_CTX,

};



static const struct bpf_func_proto *

bpf_base_func_proto(enum bpf_func_id func_id)

{
@@ -2640,6 +2653,8 @@ sk_filter_func_proto(enum bpf_func_id func_id) 
	switch (func_id) {

	case BPF_FUNC_skb_load_bytes:

		return &bpf_skb_load_bytes_proto;

	case BPF_FUNC_get_socket_cookie:

		return &bpf_get_socket_cookie_proto;

	default:

		return bpf_base_func_proto(func_id);

	}
@@ -2699,6 +2714,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id) 
		return &bpf_get_smp_processor_id_proto;

	case BPF_FUNC_skb_under_cgroup:

		return &bpf_skb_under_cgroup_proto;

	case BPF_FUNC_get_socket_cookie:

		return &bpf_get_socket_cookie_proto;

	default:

		return bpf_base_func_proto(func_id);

	}

net/core/sock_diag.c

+1 −1
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh); 
static DEFINE_MUTEX(sock_diag_table_mutex);

static struct workqueue_struct *broadcast_wq;



static u64 sock_gen_cookie(struct sock *sk)

u64 sock_gen_cookie(struct sock *sk)

{

	while (1) {

		u64 res = atomic64_read(&sk->sk_cookie);

tools/include/uapi/linux/bpf.h

+2 −1
Original line number Diff line number Diff line
@@ -506,7 +506,8 @@ union bpf_attr { 
	FN(get_numa_node_id),		\

	FN(skb_change_head),		\

	FN(xdp_adjust_head),		\

	FN(probe_read_str),

	FN(probe_read_str),		\

	FN(get_socket_cookie),



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

 * function eBPF program intends to call

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