From: Chenbo Feng <fe...@google.com>
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.
Signed-off-by: Chenbo Feng <chenbofeng.ker...@gmail.com>
---
include/linux/sock_diag.h | 1 +
include/uapi/linux/bpf.h | 9 ++++++++-
net/core/filter.c | 15 +++++++++++++++
net/core/sock_diag.c | 2 +-
4 files changed, 25 insertions(+), 2 deletions(-)
diff --git a/include/linux/sock_diag.h b/include/linux/sock_diag.h
index a0596ca0..a2f8109 100644
--- a/include/linux/sock_diag.h
+++ b/include/linux/sock_diag.h
@@ -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);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e07fd5a..6923d21 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -449,6 +449,12 @@ 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), \
@@ -496,7 +502,8 @@ 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
diff --git a/net/core/filter.c b/net/core/filter.c
index 0b753cb..632fb91 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -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>
@@ -2599,6 +2600,18 @@ 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)
{
@@ -2622,6 +2635,8 @@ bpf_base_func_proto(enum bpf_func_id func_id)
case BPF_FUNC_trace_printk:
if (capable(CAP_SYS_ADMIN))
return bpf_get_trace_printk_proto();
+ case BPF_FUNC_get_socket_cookie:
+ return &bpf_get_socket_cookie_proto;
default:
return NULL;
}
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index 6b10573..acd2a6c 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -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);
--
2.7.4
