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: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Chenbo Feng <fengc@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Chenbo Feng 2017-03-22 17:27:34 -07:00 committed by David S. Miller
parent 16ae1f2236
commit 91b8270f2a
5 changed files with 29 additions and 3 deletions

View File

@ -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);

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@ -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

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@ -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);
}

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@ -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);

View File

@ -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