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[RFC PATCH v2 3/3] bpf: add sample for BPF_MAP_TYPE_QUEUE

Mauricio Vasquez
 

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@...>
---
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;
+}