This patch adds a new bpf helper BPF_FUNC_tcp_enter_cwr
"int bpf_tcp_enter_cwr(struct bpf_tcp_sock *tp)".
It is added to BPF_PROG_TYPE_CGROUP_SKB typed bpf_prog
which currently can be attached to the ingress and egress
path.
This helper makes a tcp_sock enter CWR state. It can be used
by a bpf_prog to manage egress network bandwidth limit per
cgroupv2. A later patch will have a sample program to
show how it can be used to limit bandwidth usage per cgroupv2.
Signed-off-by: Lawrence Brakmo <bra...@fb.com>
Signed-off-by: Martin KaFai Lau <ka...@fb.com>
---
include/linux/bpf.h | 1 +
include/uapi/linux/bpf.h | 9 ++++++++-
kernel/bpf/verifier.c | 4 ++++
net/core/filter.c | 14 ++++++++++++++
4 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index de18227b3d95..525628c913c9 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -195,6 +195,7 @@ enum bpf_arg_type {
ARG_PTR_TO_SOCKET, /* pointer to bpf_sock */
ARG_PTR_TO_SPIN_LOCK, /* pointer to bpf_spin_lock */
ARG_PTR_TO_SOCK_COMMON, /* pointer to sock_common */
+ ARG_PTR_TO_TCP_SOCK, /* pointer to tcp_sock */
};
/* type of values returned from helper functions */
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index bcdd2474eee7..9e9f4f1a0370 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2359,6 +2359,12 @@ union bpf_attr {
* Return
* A **struct bpf_tcp_sock** pointer on success, or NULL in
* case of failure.
+ *
+ * int bpf_tcp_enter_cwr(struct bpf_tcp_sock *tp)
+ * Description
+ * Make a tcp_sock enter CWR state.
+ * Return
+ * 0
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -2457,7 +2463,8 @@ union bpf_attr {
FN(spin_lock), \
FN(spin_unlock), \
FN(sk_fullsock), \
- FN(tcp_sock),
+ FN(tcp_sock), \
+ FN(tcp_enter_cwr),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1b9496c41383..95fb385c6f3c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2424,6 +2424,10 @@ static int check_func_arg(struct bpf_verifier_env *env,
u32 regno,
return -EFAULT;
}
meta->ptr_id = reg->id;
+ } else if (arg_type == ARG_PTR_TO_TCP_SOCK) {
+ expected_type = PTR_TO_TCP_SOCK;
+ if (type != expected_type)
+ goto err_type;
} else if (arg_type == ARG_PTR_TO_SPIN_LOCK) {
if (meta->func_id == BPF_FUNC_spin_lock) {
if (process_spin_lock(env, regno, true))
diff --git a/net/core/filter.c b/net/core/filter.c
index b584cb42a803..f51c4a781844 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5426,6 +5426,18 @@ static const struct bpf_func_proto bpf_tcp_sock_proto = {
.arg1_type = ARG_PTR_TO_SOCK_COMMON,
};
+BPF_CALL_1(bpf_tcp_enter_cwr, struct tcp_sock *, tp)
+{
+ tcp_enter_cwr((struct sock *)tp);
+ return 0;
+}
+
+static const struct bpf_func_proto bpf_tcp_enter_cwr_proto = {
+ .func = bpf_tcp_enter_cwr,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_TCP_SOCK,
+};
#endif /* CONFIG_INET */
bool bpf_helper_changes_pkt_data(void *func)
@@ -5585,6 +5597,8 @@ cg_skb_func_proto(enum bpf_func_id func_id, const struct
bpf_prog *prog)
#ifdef CONFIG_INET
case BPF_FUNC_tcp_sock:
return &bpf_tcp_sock_proto;
+ case BPF_FUNC_tcp_enter_cwr:
+ return &bpf_tcp_enter_cwr_proto;
#endif
default:
return sk_filter_func_proto(func_id, prog);
--
2.17.1
