From 69e8cc134bcbf0ccfcf852c400b8e6788d1d0038 Mon Sep 17 00:00:00 2001
From: John Fastabend <john.fastabend@gmail.com>
Date: Tue, 15 Aug 2017 22:33:32 -0700
Subject: bpf: sockmap sample program

This program binds a program to a cgroup and then matches hard
coded IP addresses and adds these to a sockmap.

This will receive messages from the backend and send them to
the client.

     client:X <---> frontend:10000 client:X <---> backend:10001

To keep things simple this is only designed for 1:1 connections
using hard coded values. A more complete example would allow many
backends and clients.

To run,

 # sockmap <cgroup2_dir>

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 samples/sockmap/sockmap_kern.c | 110 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 samples/sockmap/sockmap_kern.c

(limited to 'samples/sockmap/sockmap_kern.c')

diff --git a/samples/sockmap/sockmap_kern.c b/samples/sockmap/sockmap_kern.c
new file mode 100644
index 000000000000..6ff986f7059b
--- /dev/null
+++ b/samples/sockmap/sockmap_kern.c
@@ -0,0 +1,110 @@
+/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <uapi/linux/bpf.h>
+#include <uapi/linux/if_ether.h>
+#include <uapi/linux/if_packet.h>
+#include <uapi/linux/ip.h>
+#include "../../tools/testing/selftests/bpf/bpf_helpers.h"
+#include "../../tools/testing/selftests/bpf/bpf_endian.h"
+
+/* Sockmap sample program connects a client and a backend together
+ * using cgroups.
+ *
+ *    client:X <---> frontend:80 client:X <---> backend:80
+ *
+ * For simplicity we hard code values here and bind 1:1. The hard
+ * coded values are part of the setup in sockmap.sh script that
+ * is associated with this BPF program.
+ *
+ * The bpf_printk is verbose and prints information as connections
+ * are established and verdicts are decided.
+ */
+
+#define bpf_printk(fmt, ...)					\
+({								\
+	       char ____fmt[] = fmt;				\
+	       bpf_trace_printk(____fmt, sizeof(____fmt),	\
+				##__VA_ARGS__);			\
+})
+
+struct bpf_map_def SEC("maps") sock_map = {
+	.type = BPF_MAP_TYPE_SOCKMAP,
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.max_entries = 20,
+};
+
+SEC("sk_skb1")
+int bpf_prog1(struct __sk_buff *skb)
+{
+	return skb->len;
+}
+
+SEC("sk_skb2")
+int bpf_prog2(struct __sk_buff *skb)
+{
+	__u32 lport = skb->local_port;
+	__u32 rport = skb->remote_port;
+	int ret = 0;
+
+	if (lport == 10000)
+		ret = 10;
+	else
+		ret = 1;
+
+	bpf_printk("sockmap: %d -> %d @ %d\n", lport, bpf_ntohl(rport), ret);
+	return bpf_sk_redirect_map(&sock_map, ret, 0);
+}
+
+SEC("sockops")
+int bpf_sockmap(struct bpf_sock_ops *skops)
+{
+	__u32 lport, rport;
+	int op, err = 0, index, key, ret;
+
+
+	op = (int) skops->op;
+
+	switch (op) {
+	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
+		lport = skops->local_port;
+		rport = skops->remote_port;
+
+		if (lport == 10000) {
+			ret = 1;
+			err = bpf_sock_map_update(skops, &sock_map, &ret,
+						  BPF_NOEXIST,
+						  BPF_SOCKMAP_STRPARSER);
+			bpf_printk("passive(%i -> %i) map ctx update err: %d\n",
+				   lport, bpf_ntohl(rport), err);
+		}
+		break;
+	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
+		lport = skops->local_port;
+		rport = skops->remote_port;
+
+		if (bpf_ntohl(rport) == 10001) {
+			ret = 10;
+			err = bpf_sock_map_update(skops, &sock_map, &ret,
+						  BPF_NOEXIST,
+						  BPF_SOCKMAP_STRPARSER);
+			bpf_printk("active(%i -> %i) map ctx update err: %d\n",
+				   lport, bpf_ntohl(rport), err);
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+char _license[] SEC("license") = "GPL";
-- 
cgit