[PATCH bpf-next 3/3] bpf: add sample for BPF_MAP_TYPE_QUEUE

[Mauricio Vasquez B <mauricio.vasquez@polito.it>]

The example is made by two parts, a eBPF program that consumes elements
from a FIFO queue and prints them in the screen and a user space
application that inserts new elements into the queue each time this is
executed.

Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@polito.it>
---
 samples/bpf/.gitignore             |    1 +
 samples/bpf/Makefile               |    3 ++
 samples/bpf/test_map_in_map_user.c |    9 +-----
 samples/bpf/test_queuemap.sh       |   37 +++++++++++++++++++++++++
 samples/bpf/test_queuemap_kern.c   |   51 +++++++++++++++++++++++++++++++++++
 samples/bpf/test_queuemap_user.c   |   53 ++++++++++++++++++++++++++++++++++++
 6 files changed, 147 insertions(+), 7 deletions(-)
 create mode 100755 samples/bpf/test_queuemap.sh
 create mode 100644 samples/bpf/test_queuemap_kern.c
 create mode 100644 samples/bpf/test_queuemap_user.c

diff --git a/samples/bpf/.gitignore b/samples/bpf/.gitignore
index 8ae4940025f8..d7e518c1b3ed 100644
--- a/samples/bpf/.gitignore
+++ b/samples/bpf/.gitignore
@@ -26,6 +26,7 @@ test_lru_dist
 test_map_in_map
 test_overhead
 test_probe_write_user
+test_queuemap
 trace_event
 trace_output
 tracex1
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index f88d5683d6ee..624f4f4b81db 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -53,6 +53,7 @@ hostprogs-y += xdpsock
 hostprogs-y += xdp_fwd
 hostprogs-y += task_fd_query
 hostprogs-y += xdp_sample_pkts
+hostprogs-y += test_queuemap
 
 # Libbpf dependencies
 LIBBPF = $(TOOLS_PATH)/lib/bpf/libbpf.a
@@ -109,6 +110,7 @@ xdpsock-objs := xdpsock_user.o
 xdp_fwd-objs := xdp_fwd_user.o
 task_fd_query-objs := bpf_load.o task_fd_query_user.o $(TRACE_HELPERS)
 xdp_sample_pkts-objs := xdp_sample_pkts_user.o $(TRACE_HELPERS)
+test_queuemap-objs := bpf_load.o test_queuemap_user.o
 
 # Tell kbuild to always build the programs
 always := $(hostprogs-y)
@@ -166,6 +168,7 @@ always += xdpsock_kern.o
 always += xdp_fwd_kern.o
 always += task_fd_query_kern.o
 always += xdp_sample_pkts_kern.o
+always += test_queuemap_kern.o
 
 HOSTCFLAGS += -I$(objtree)/usr/include
 HOSTCFLAGS += -I$(srctree)/tools/lib/
diff --git a/samples/bpf/test_map_in_map_user.c b/samples/bpf/test_map_in_map_user.c
index e308858f7bcf..28edac94234e 100644
--- a/samples/bpf/test_map_in_map_user.c
+++ b/samples/bpf/test_map_in_map_user.c
@@ -1,10 +1,5 @@
-/*
- * Copyright (c) 2017 Facebook
- *
- * 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.
- */
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2018 Politecnico di Torino */
 #include <sys/resource.h>
 #include <sys/socket.h>
 #include <arpa/inet.h>
diff --git a/samples/bpf/test_queuemap.sh b/samples/bpf/test_queuemap.sh
new file mode 100755
index 000000000000..ed08c1fa8c2c
--- /dev/null
+++ b/samples/bpf/test_queuemap.sh
@@ -0,0 +1,37 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+[[ -z $TC ]] && TC='tc'
+[[ -z $IP ]] && IP='ip'
+
+TEST_QUEUE_USER='./test_queuemap'
+TEST_QUEUE_BPF='./test_queuemap_kern.o'
+
+function config {
+	$IP netns add ns1
+	$IP link add ve1 type veth peer name vens1
+	$IP link set dev ve1 up
+	$IP link set dev ve1 mtu 1500
+	$IP link set dev vens1 netns ns1
+
+	$IP -n ns1 link set dev lo up
+	$IP -n ns1 link set dev vens1 up
+	$IP -n ns1 addr add 10.1.1.101/24 dev vens1
+
+	$IP addr add 10.1.1.1/24 dev ve1
+	$TC qdisc add dev ve1 clsact
+	$TC filter add dev ve1 ingress bpf da obj $TEST_QUEUE_BPF sec test_queue
+}
+
+function cleanup {
+	set +e
+	[[ -z $DEBUG ]] || set +x
+	$IP netns delete ns1 >& /dev/null
+	$IP link del ve1 >& /dev/null
+	rm -f /sys/fs/bpf/tc/globals/queue
+	[[ -z $DEBUG ]] || set -x
+	set -e
+}
+
+cleanup
+config
diff --git a/samples/bpf/test_queuemap_kern.c b/samples/bpf/test_queuemap_kern.c
new file mode 100644
index 000000000000..2b496dafaffd
--- /dev/null
+++ b/samples/bpf/test_queuemap_kern.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2018 Politecnico di Torino */
+#define KBUILD_MODNAME "foo"
+#include <linux/ptrace.h>
+#include <linux/version.h>
+#include <uapi/linux/bpf.h>
+#include <uapi/linux/in6.h>
+#include <uapi/linux/pkt_cls.h>
+#include "bpf_helpers.h"
+
+#define PIN_GLOBAL_NS		2
+
+struct bpf_elf_map {
+	__u32 type;
+	__u32 key_size;
+	__u32 value_size;
+	__u32 max_entries;
+	__u32 flags;
+	__u32 id;
+	__u32 pinning;
+};
+
+/* map #0 */
+struct bpf_elf_map SEC("maps") queue = {
+	.type = BPF_MAP_TYPE_QUEUE,
+	.key_size = 0,
+	.value_size = sizeof(u32),
+	.flags = BPF_F_QUEUE_FIFO,
+	.max_entries = 1024,
+	.pinning = PIN_GLOBAL_NS,
+};
+
+SEC("test_queue")
+int _test_queue(struct __sk_buff *skb)
+{
+	char msg[] = "element is %u\n";
+	char msg_no[] = "there are not elements\n";
+
+	u32 *val = bpf_map_lookup_elem(&queue, NULL);
+
+	if (!val) {
+		bpf_trace_printk(msg_no, sizeof(msg_no));
+		return TC_ACT_OK;
+	}
+
+	bpf_trace_printk(msg, sizeof(msg), *val);
+	return TC_ACT_OK;
+}
+
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;
diff --git a/samples/bpf/test_queuemap_user.c b/samples/bpf/test_queuemap_user.c
new file mode 100644
index 000000000000..68f9a5d54596
--- /dev/null
+++ b/samples/bpf/test_queuemap_user.c
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2018 Politecnico di Torino
+ *
+ * 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.
+ */
+#include <sys/resource.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <stdint.h>
+#include <assert.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <bpf/bpf.h>
+#include "bpf_load.h"
+
+int queue_map;
+
+static void test_queue_map(void)
+{
+	int ret;
+	uint32_t i;
+
+	queue_map = bpf_obj_get("/sys/fs/bpf/tc/globals/queue");
+	if (queue_map < 0) {
+		fprintf(stderr, "error getting map");
+		return;
+	}
+
+	for (i = 0; i < 256; i++) {
+		uint32_t v = 1000 - i*3;
+
+		ret = bpf_map_update_elem(queue_map, NULL, &v, 0);
+		if (ret)
+			fprintf(stderr, "ret is %d\n", ret);
+	}
+}
+
+int main(int argc, char **argv)
+{
+	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+	char filename[256];
+
+	assert(!setrlimit(RLIMIT_MEMLOCK, &r));
+
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+	test_queue_map();
+
+	return 0;
+}