Simple Proof-Of-Concept test program for BPF_TCP_INFO_NOTIFY
(will move this to testing/selftests/net later)
Signed-off-by: Sowmini Varadhan <sowmini.varad...@oracle.com>
---
samples/bpf/Makefile | 1 +
samples/bpf/tcp_notify_kern.c | 73 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 74 insertions(+), 0 deletions(-)
create mode 100644 samples/bpf/tcp_notify_kern.c
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index be0a961..d937bd2 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -152,6 +152,7 @@ always += tcp_bufs_kern.o
always += tcp_cong_kern.o
always += tcp_iw_kern.o
always += tcp_clamp_kern.o
+always += tcp_notify_kern.o
always += tcp_basertt_kern.o
always += tcp_tos_reflect_kern.o
always += xdp_redirect_kern.o
diff --git a/samples/bpf/tcp_notify_kern.c b/samples/bpf/tcp_notify_kern.c
new file mode 100644
index 0000000..bc4efd8
--- /dev/null
+++ b/samples/bpf/tcp_notify_kern.c
@@ -0,0 +1,73 @@
+/* Sample BPF program to demonstrate how to triger async tcp_info
+ * notification based on thresholds determeined in the filter.
+ * The example here will trigger notification if skops->total_retrans > 16
+ *
+ * Use load_sock_ops to load this BPF program.
+ */
+
+#include <uapi/linux/bpf.h>
+#include <uapi/linux/if_ether.h>
+#include <uapi/linux/if_packet.h>
+#include <uapi/linux/ip.h>
+#include <linux/socket.h>
+#include "bpf_helpers.h"
+#include "bpf_endian.h"
+
+#define DEBUG 0
+
+#define bpf_printk(fmt, ...) \
+({ \
+ char ____fmt[] = fmt; \
+ bpf_trace_printk(____fmt, sizeof(____fmt), \
+ ##__VA_ARGS__); \
+})
+
+SEC("sockops")
+int bpf_tcp_info_notify(struct bpf_sock_ops *skops)
+{
+ int bufsize = 150000;
+ int to_init = 10;
+ int clamp = 100;
+ int rv = 0;
+ int op;
+
+ /* For testing purposes, only execute rest of BPF program
+ * if neither port numberis 5001 (default iperf port)
+ */
+ if (bpf_ntohl(skops->remote_port) != 5001 &&
+ skops->local_port != 5001) {
+ skops->reply = -1;
+ return 0;
+ }
+
+ op = (int) skops->op;
+
+#ifdef DEBUG
+ bpf_printk("BPF command: %d\n", op);
+#endif
+
+ switch (op) {
+ case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
+ case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
+ bpf_sock_ops_cb_flags_set(skops,
+ (BPF_SOCK_OPS_RETRANS_CB_FLAG|
+ BPF_SOCK_OPS_RTO_CB_FLAG));
+ rv = 1;
+ break;
+ case BPF_SOCK_OPS_RETRANS_CB:
+ case BPF_SOCK_OPS_RTO_CB:
+ if (skops->total_retrans < 16)
+ rv = 1; /* skip */
+ else
+ rv = BPF_TCP_INFO_NOTIFY;
+ break;
+ default:
+ rv = -1;
+ }
+#ifdef DEBUG
+ bpf_printk("Returning %d\n", rv);
+#endif
+ skops->reply = rv;
+ return 1;
+}
+char _license[] SEC("license") = "GPL";
--
1.7.1
