xdp: bpf redirect with map sample program

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Tested-by: Andy Gospodarek <andy@greyhouse.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 192 insertions, 0 deletions

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 97734ced947e..770d46cdf9f4 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -38,6 +38,7 @@ hostprogs-y += test_map_in_map
 hostprogs-y += per_socket_stats_example
 hostprogs-y += load_sock_ops
 hostprogs-y += xdp_redirect
+hostprogs-y += xdp_redirect_map
 
 # Libbpf dependencies
 LIBBPF := ../../tools/lib/bpf/bpf.o
@@ -80,6 +81,7 @@ xdp_tx_iptunnel-objs := bpf_load.o $(LIBBPF) xdp_tx_iptunnel_user.o
 test_map_in_map-objs := bpf_load.o $(LIBBPF) test_map_in_map_user.o
 per_socket_stats_example-objs := $(LIBBPF) cookie_uid_helper_example.o
 xdp_redirect-objs := bpf_load.o $(LIBBPF) xdp_redirect_user.o
+xdp_redirect_map-objs := bpf_load.o $(LIBBPF) xdp_redirect_map_user.o
 
 # Tell kbuild to always build the programs
 always := $(hostprogs-y)
@@ -122,6 +124,7 @@ always += tcp_cong_kern.o
 always += tcp_iw_kern.o
 always += tcp_clamp_kern.o
 always += xdp_redirect_kern.o
+always += xdp_redirect_map_kern.o
 
 HOSTCFLAGS += -I$(objtree)/usr/include
 HOSTCFLAGS += -I$(srctree)/tools/lib/
@@ -159,6 +162,7 @@ HOSTLOADLIBES_lwt_len_hist += -l elf
 HOSTLOADLIBES_xdp_tx_iptunnel += -lelf
 HOSTLOADLIBES_test_map_in_map += -lelf
 HOSTLOADLIBES_xdp_redirect += -lelf
+HOSTLOADLIBES_xdp_redirect_map += -lelf
 
 # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
 #  make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
diff --git a/samples/bpf/xdp_redirect_map_kern.c b/samples/bpf/xdp_redirect_map_kern.c
new file mode 100644
index 000000000000..2faf196e17ea
--- /dev/null
+++ b/samples/bpf/xdp_redirect_map_kern.c
@@ -0,0 +1,83 @@
+/* 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.
+ */
+#define KBUILD_MODNAME "foo"
+#include <uapi/linux/bpf.h>
+#include <linux/in.h>
+#include <linux/if_ether.h>
+#include <linux/if_packet.h>
+#include <linux/if_vlan.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include "bpf_helpers.h"
+
+struct bpf_map_def SEC("maps") tx_port = {
+        .type = BPF_MAP_TYPE_DEVMAP,
+        .key_size = sizeof(int),
+        .value_size = sizeof(int),
+        .max_entries = 100,
+};
+
+struct bpf_map_def SEC("maps") rxcnt = {
+        .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+        .key_size = sizeof(u32),
+        .value_size = sizeof(long),
+        .max_entries = 1,
+};
+
+
+static void swap_src_dst_mac(void *data)
+{
+        unsigned short *p = data;
+        unsigned short dst[3];
+
+        dst[0] = p[0];
+        dst[1] = p[1];
+        dst[2] = p[2];
+        p[0] = p[3];
+        p[1] = p[4];
+        p[2] = p[5];
+        p[3] = dst[0];
+        p[4] = dst[1];
+        p[5] = dst[2];
+}
+
+SEC("xdp_redirect_map")
+int xdp_redirect_map_prog(struct xdp_md *ctx)
+{
+        void *data_end = (void *)(long)ctx->data_end;
+        void *data = (void *)(long)ctx->data;
+        struct ethhdr *eth = data;
+        int rc = XDP_DROP;
+        int vport, port = 0, m = 0;
+        long *value;
+        u32 key = 0;
+        u64 nh_off;
+
+        nh_off = sizeof(*eth);
+        if (data + nh_off > data_end)
+                return rc;
+
+        /* constant virtual port */
+        vport = 0;
+
+        /* count packet in global counter */
+        value = bpf_map_lookup_elem(&rxcnt, &key);
+        if (value)
+                *value += 1;
+
+        swap_src_dst_mac(data);
+
+        /* send packet out physical port */
+        return bpf_redirect_map(&tx_port, vport, 0);
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/samples/bpf/xdp_redirect_map_user.c b/samples/bpf/xdp_redirect_map_user.c
new file mode 100644
index 000000000000..0b8009a85415
--- /dev/null
+++ b/samples/bpf/xdp_redirect_map_user.c
@@ -0,0 +1,105 @@
+/* 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 <linux/bpf.h>
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "bpf_load.h"
+#include "bpf_util.h"
+#include "libbpf.h"
+
+static int ifindex_in;
+static int ifindex_out;
+
+static void int_exit(int sig)
+{
+        set_link_xdp_fd(ifindex_in, -1, 0);
+        exit(0);
+}
+
+/* simple per-protocol drop counter
+ */
+static void poll_stats(int interval, int ifindex)
+{
+        unsigned int nr_cpus = bpf_num_possible_cpus();
+        __u64 values[nr_cpus], prev[nr_cpus];
+
+        memset(prev, 0, sizeof(prev));
+
+        while (1) {
+                __u64 sum = 0;
+                __u32 key = 0;
+                int i;
+
+                sleep(interval);
+                assert(bpf_map_lookup_elem(map_fd[1], &key, values) == 0);
+                for (i = 0; i < nr_cpus; i++)
+                        sum += (values[i] - prev[i]);
+                if (sum)
+                        printf("ifindex %i: %10llu pkt/s\n",
+                               ifindex, sum / interval);
+                memcpy(prev, values, sizeof(values));
+        }
+}
+
+int main(int ac, char **argv)
+{
+        char filename[256];
+        int ret, key = 0;
+
+        snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+        if (ac != 3) {
+                printf("usage: %s IFINDEX_IN IFINDEX_OUT\n", argv[0]);
+                return 1;
+        }
+
+        ifindex_in = strtoul(argv[1], NULL, 0);
+        ifindex_out = strtoul(argv[2], NULL, 0);
+
+        if (load_bpf_file(filename)) {
+                printf("%s", bpf_log_buf);
+                return 1;
+        }
+
+        if (!prog_fd[0]) {
+                printf("load_bpf_file: %s\n", strerror(errno));
+                return 1;
+        }
+
+        signal(SIGINT, int_exit);
+
+        if (set_link_xdp_fd(ifindex_in, prog_fd[0], 0) < 0) {
+                printf("link set xdp fd failed\n");
+                return 1;
+        }
+
+        printf("map[0] (vports) = %i, map[1] (map) = %i, map[2] (count) = %i\n",
+                map_fd[0], map_fd[1], map_fd[2]);
+
+        /* populate virtual to physical port map */
+        ret = bpf_map_update_elem(map_fd[0], &key, &ifindex_out, 0);
+        if (ret) {
+                perror("bpf_update_elem");
+                goto out;
+        }
+
+        poll_stats(2, ifindex_out);
+
+out:
+        return 0;
+}