bpf: selftests add sockmap tests

This generates a set of sockets, attaches BPF programs, and sends some
simple traffic using basic send/recv pattern. Additionally, we do a bunch
of negative tests to ensure adding/removing socks out of the sockmap fail
correctly.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/tools/testing/selftests/bpf/sockmap_parse_prog.c b/tools/testing/selftests/bpf/sockmap_parse_prog.c
new file mode 100644
index 0000000..8b54531
--- /dev/null
+++ b/tools/testing/selftests/bpf/sockmap_parse_prog.c
@@ -0,0 +1,38 @@
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+#include "bpf_util.h"
+#include "bpf_endian.h"
+
+int _version SEC("version") = 1;
+
+#define bpf_printk(fmt, ...)					\
+({								\
+	       char ____fmt[] = fmt;				\
+	       bpf_trace_printk(____fmt, sizeof(____fmt),	\
+				##__VA_ARGS__);			\
+})
+
+SEC("sk_skb1")
+int bpf_prog1(struct __sk_buff *skb)
+{
+	void *data_end = (void *)(long) skb->data_end;
+	void *data = (void *)(long) skb->data;
+	__u32 lport = skb->local_port;
+	__u32 rport = skb->remote_port;
+	char *d = data;
+
+	if (data + 8 > data_end)
+		return skb->len;
+
+	/* This write/read is a bit pointless but tests the verifier and
+	 * strparser handler for read/write pkt data and access into sk
+	 * fields.
+	 */
+	d[0] = 1;
+
+	bpf_printk("data[0] = (%u): local_port %i remote %i\n",
+		   d[0], lport, bpf_ntohl(rport));
+	return skb->len;
+}
+
+char _license[] SEC("license") = "GPL";