Subject: [PATCH bpf-next v2 5/8] samples: bpf: Convert xdp_redirect to use XDP samples helper

From: Kumar Kartikeya Dwivedi <[email-masked]>
Date: Thu, 22 Jul 2021 02:58:30 +0530

This change converts XDP redirect tool to use the XDP samples support
introduced in previous changes.

Signed-off-by: Kumar Kartikeya Dwivedi <[email-masked]>
---
 samples/bpf/Makefile            |  10 +-
 samples/bpf/xdp_redirect.bpf.c  |  52 +++++++
 samples/bpf/xdp_redirect_kern.c |  90 -----------
 samples/bpf/xdp_redirect_user.c | 262 +++++++++++++-------------------
 4 files changed, 160 insertions(+), 254 deletions(-)
 create mode 100644 samples/bpf/xdp_redirect.bpf.c
 delete mode 100644 samples/bpf/xdp_redirect_kern.c

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 1b4838b2beb0..b94b6dac09ff 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -39,7 +39,6 @@ tprogs-y += lwt_len_hist
 tprogs-y += xdp_tx_iptunnel
 tprogs-y += test_map_in_map
 tprogs-y += per_socket_stats_example
-tprogs-y += xdp_redirect
 tprogs-y += xdp_redirect_map
 tprogs-y += xdp_redirect_map_multi
 tprogs-y += xdp_redirect_cpu
@@ -56,6 +55,7 @@ tprogs-y += xdp_sample_pkts
 tprogs-y += ibumad
 tprogs-y += hbm
 
+tprogs-y += xdp_redirect
 tprogs-y += xdp_monitor
 
 # Libbpf dependencies
@@ -100,7 +100,6 @@ lwt_len_hist-objs := lwt_len_hist_user.o
 xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
 test_map_in_map-objs := test_map_in_map_user.o
 per_socket_stats_example-objs := cookie_uid_helper_example.o
-xdp_redirect-objs := xdp_redirect_user.o
 xdp_redirect_map-objs := xdp_redirect_map_user.o
 xdp_redirect_map_multi-objs := xdp_redirect_map_multi_user.o
 xdp_redirect_cpu-objs := xdp_redirect_cpu_user.o
@@ -118,6 +117,7 @@ ibumad-objs := ibumad_user.o
 hbm-objs := hbm.o $(CGROUP_HELPERS)
 
 xdp_sample_user-objs := xdp_sample_user.o $(LIBBPFDIR)/hashmap.o
+xdp_redirect-objs := xdp_redirect_user.o $(XDP_SAMPLE)
 xdp_monitor-objs := xdp_monitor_user.o $(XDP_SAMPLE)
 
 # Tell kbuild to always build the programs
@@ -164,7 +164,6 @@ always-y += tcp_clamp_kern.o
 always-y += tcp_basertt_kern.o
 always-y += tcp_tos_reflect_kern.o
 always-y += tcp_dumpstats_kern.o
-always-y += xdp_redirect_kern.o
 always-y += xdp_redirect_map_kern.o
 always-y += xdp_redirect_map_multi_kern.o
 always-y += xdp_redirect_cpu_kern.o
@@ -315,6 +314,7 @@ verify_target_bpf: verify_cmds
 $(BPF_SAMPLES_PATH)/*.c: verify_target_bpf $(LIBBPF)
 $(src)/*.c: verify_target_bpf $(LIBBPF)
 
+$(obj)/xdp_redirect_user.o: $(obj)/xdp_redirect.skel.h
 $(obj)/xdp_monitor_user.o: $(obj)/xdp_monitor.skel.h
 
 $(obj)/tracex5_kern.o: $(obj)/syscall_nrs.h
@@ -358,6 +358,7 @@ endef
 
 CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))
 
+$(obj)/xdp_redirect.bpf.o: $(obj)/xdp_sample.bpf.o
 $(obj)/xdp_monitor.bpf.o: $(obj)/xdp_sample.bpf.o
 
 $(obj)/%.bpf.o: $(src)/%.bpf.c $(obj)/vmlinux.h $(src)/xdp_sample.bpf.h $(src)/xdp_sample_shared.h
@@ -368,9 +369,10 @@ $(obj)/%.bpf.o: $(src)/%.bpf.c $(obj)/vmlinux.h $(src)/xdp_sample.bpf.h $(src)/x
 		-I$(srctree)/tools/lib $(CLANG_SYS_INCLUDES) \
 		-c $(filter %.bpf.c,$^) -o $@
 
-LINKED_SKELS := xdp_monitor.skel.h
+LINKED_SKELS := xdp_redirect.skel.h xdp_monitor.skel.h
 clean-files += $(LINKED_SKELS)
 
+xdp_redirect.skel.h-deps := xdp_redirect.bpf.o xdp_sample.bpf.o
 xdp_monitor.skel.h-deps := xdp_monitor.bpf.o xdp_sample.bpf.o
 
 LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.bpf.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps)))
diff --git a/samples/bpf/xdp_redirect.bpf.c b/samples/bpf/xdp_redirect.bpf.c
new file mode 100644
index 000000000000..f5098812db36
--- /dev/null
+++ b/samples/bpf/xdp_redirect.bpf.c
@@ -0,0 +1,52 @@
+/* Copyright (c) 2016 John Fastabend <[email-masked]>
+ *
+ * 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 "vmlinux.h"
+#include "xdp_sample.bpf.h"
+#include "xdp_sample_shared.h"
+
+const volatile int ifindex_out;
+
+SEC("xdp_redirect")
+int xdp_redirect_prog(struct xdp_md *ctx)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	u32 key = bpf_get_smp_processor_id();
+	struct ethhdr *eth = data;
+	struct datarec *rec;
+	u64 nh_off;
+
+	nh_off = sizeof(*eth);
+	if (data + nh_off > data_end)
+		return XDP_DROP;
+
+	if (key < MAX_CPUS) {
+		rec = &sample_data.rx_cnt[key];
+		ATOMIC_INC_NORMW(rec->processed);
+
+		swap_src_dst_mac(data);
+		return bpf_redirect(ifindex_out, 0);
+	}
+
+	return XDP_PASS;
+}
+
+/* Redirect require an XDP bpf_prog loaded on the TX device */
+SEC("xdp_redirect_dummy")
+int xdp_redirect_dummy_prog(struct xdp_md *ctx)
+{
+	return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/samples/bpf/xdp_redirect_kern.c b/samples/bpf/xdp_redirect_kern.c
deleted file mode 100644
index d26ec3aa215e..000000000000
--- a/samples/bpf/xdp_redirect_kern.c
+++ /dev/null
@@ -1,90 +0,0 @@
-/* Copyright (c) 2016 John Fastabend <[email-masked]>
- *
- * 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/bpf_helpers.h>
-
-struct {
-	__uint(type, BPF_MAP_TYPE_ARRAY);
-	__type(key, int);
-	__type(value, int);
-	__uint(max_entries, 1);
-} tx_port SEC(".maps");
-
-/* Count RX packets, as XDP bpf_prog doesn't get direct TX-success
- * feedback.  Redirect TX errors can be caught via a tracepoint.
- */
-struct {
-	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
-	__type(key, u32);
-	__type(value, long);
-	__uint(max_entries, 1);
-} rxcnt SEC(".maps");
-
-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")
-int xdp_redirect_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 *ifindex, port = 0;
-	long *value;
-	u32 key = 0;
-	u64 nh_off;
-
-	nh_off = sizeof(*eth);
-	if (data + nh_off > data_end)
-		return rc;
-
-	ifindex = bpf_map_lookup_elem(&tx_port, &port);
-	if (!ifindex)
-		return rc;
-
-	value = bpf_map_lookup_elem(&rxcnt, &key);
-	if (value)
-		*value += 1;
-
-	swap_src_dst_mac(data);
-	return bpf_redirect(*ifindex, 0);
-}
-
-/* Redirect require an XDP bpf_prog loaded on the TX device */
-SEC("xdp_redirect_dummy")
-int xdp_redirect_dummy_prog(struct xdp_md *ctx)
-{
-	return XDP_PASS;
-}
-
-char _license[] SEC("license") = "GPL";
diff --git a/samples/bpf/xdp_redirect_user.c b/samples/bpf/xdp_redirect_user.c
index 93854e135134..192fd620573f 100644
--- a/samples/bpf/xdp_redirect_user.c
+++ b/samples/bpf/xdp_redirect_user.c
@@ -13,126 +13,91 @@
 #include <net/if.h>
 #include <unistd.h>
 #include <libgen.h>
+#include <getopt.h>
 #include <sys/resource.h>
-
-#include "bpf_util.h"
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
+#include "bpf_util.h"
+#include "xdp_sample_user.h"
+#include "xdp_redirect.skel.h"
 
-static int ifindex_in;
-static int ifindex_out;
-static bool ifindex_out_xdp_dummy_attached = true;
-static __u32 prog_id;
-static __u32 dummy_prog_id;
-
-static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
-static int rxcnt_map_fd;
+static int mask = SAMPLE_RX_CNT | SAMPLE_REDIRECT_ERR_CNT |
+		  SAMPLE_EXCEPTION_CNT;
 
-static void int_exit(int sig)
-{
-	__u32 curr_prog_id = 0;
+DEFINE_SAMPLE_INIT(xdp_redirect);
 
-	if (bpf_get_link_xdp_id(ifindex_in, &curr_prog_id, xdp_flags)) {
-		printf("bpf_get_link_xdp_id failed\n");
-		exit(1);
-	}
-	if (prog_id == curr_prog_id)
-		bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
-	else if (!curr_prog_id)
-		printf("couldn't find a prog id on iface IN\n");
-	else
-		printf("program on iface IN changed, not removing\n");
-
-	if (ifindex_out_xdp_dummy_attached) {
-		curr_prog_id = 0;
-		if (bpf_get_link_xdp_id(ifindex_out, &curr_prog_id,
-					xdp_flags)) {
-			printf("bpf_get_link_xdp_id failed\n");
-			exit(1);
-		}
-		if (dummy_prog_id == curr_prog_id)
-			bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
-		else if (!curr_prog_id)
-			printf("couldn't find a prog id on iface OUT\n");
-		else
-			printf("program on iface OUT changed, not removing\n");
-	}
-	exit(0);
-}
+static const struct option long_options[] = {
+	{"help",	no_argument,		NULL, 'h' },
+	{"skb-mode",	no_argument,		NULL, 'S' },
+	{"force",	no_argument,		NULL, 'F' },
+	{"stats",	no_argument,		NULL, 's' },
+	{"interval",	required_argument,	NULL, 'i' },
+	{"verbose",	no_argument,		NULL, 'v' },
+	{}
+};
 
-static void poll_stats(int interval, int ifindex)
+static void usage(char *argv[])
 {
-	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(rxcnt_map_fd, &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 i;
+
+	sample_print_help(mask);
+
+	printf("\n");
+	printf(" Usage: %s (options-see-below)\n",
+	       argv[0]);
+	printf(" Listing options:\n");
+	for (i = 0; long_options[i].name != 0; i++) {
+		printf(" --%-15s", long_options[i].name);
+		if (long_options[i].flag != NULL)
+			printf(" flag (internal value:%d)",
+			       *long_options[i].flag);
+		else
+			printf("short-option: -%c",
+			       long_options[i].val);
+		printf("\n");
 	}
+	printf("\n");
 }
 
-static void usage(const char *prog)
-{
-	fprintf(stderr,
-		"usage: %s [OPTS] <IFNAME|IFINDEX>_IN <IFNAME|IFINDEX>_OUT\n\n"
-		"OPTS:\n"
-		"    -S    use skb-mode\n"
-		"    -N    enforce native mode\n"
-		"    -F    force loading prog\n",
-		prog);
-}
-
-
 int main(int argc, char **argv)
 {
-	struct bpf_prog_load_attr prog_load_attr = {
-		.prog_type	= BPF_PROG_TYPE_XDP,
-	};
-	struct bpf_program *prog, *dummy_prog;
-	int prog_fd, tx_port_map_fd, opt;
-	struct bpf_prog_info info = {};
-	__u32 info_len = sizeof(info);
-	const char *optstr = "FSN";
-	struct bpf_object *obj;
-	char filename[256];
-	int dummy_prog_fd;
-	int ret, key = 0;
-
-	while ((opt = getopt(argc, argv, optstr)) != -1) {
+	int ifindex_in, ifindex_out, opt;
+	char str[2 * IF_NAMESIZE + 1];
+	char ifname_out[IF_NAMESIZE];
+	char ifname_in[IF_NAMESIZE];
+	int ret = EXIT_FAIL_OPTION;
+	unsigned long interval = 2;
+	struct xdp_redirect *skel;
+	bool generic = false;
+	bool force = false;
+
+	while ((opt = getopt_long(argc, argv, "SFi:vs",
+				  long_options, NULL)) != -1) {
 		switch (opt) {
 		case 'S':
-			xdp_flags |= XDP_FLAGS_SKB_MODE;
-			break;
-		case 'N':
-			/* default, set below */
+			generic = true;
 			break;
 		case 'F':
-			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
+			force = true;
+			break;
+		case 'i':
+			interval = strtoul(optarg, NULL, 0);
+			break;
+		case 'v':
+			sample_switch_mode();
+			break;
+		case 's':
+			mask |= SAMPLE_REDIRECT_CNT;
 			break;
 		default:
-			usage(basename(argv[0]));
-			return 1;
+			usage(argv);
+			return ret;
 		}
 	}
 
-	if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
-		xdp_flags |= XDP_FLAGS_DRV_MODE;
-
-	if (optind + 2 != argc) {
-		printf("usage: %s <IFNAME|IFINDEX>_IN <IFNAME|IFINDEX>_OUT\n", argv[0]);
-		return 1;
+	if (argc <= optind + 1) {
+		usage(argv);
+		return ret;
 	}
 
 	ifindex_in = if_nametoindex(argv[optind]);
@@ -143,75 +108,52 @@ int main(int argc, char **argv)
 	if (!ifindex_out)
 		ifindex_out = strtoul(argv[optind + 1], NULL, 0);
 
-	printf("input: %d output: %d\n", ifindex_in, ifindex_out);
-
-	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
-	prog_load_attr.file = filename;
-
-	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
-		return 1;
-
-	prog = bpf_program__next(NULL, obj);
-	dummy_prog = bpf_program__next(prog, obj);
-	if (!prog || !dummy_prog) {
-		printf("finding a prog in obj file failed\n");
-		return 1;
-	}
-	/* bpf_prog_load_xattr gives us the pointer to first prog's fd,
-	 * so we're missing only the fd for dummy prog
-	 */
-	dummy_prog_fd = bpf_program__fd(dummy_prog);
-	if (prog_fd < 0 || dummy_prog_fd < 0) {
-		printf("bpf_prog_load_xattr: %s\n", strerror(errno));
-		return 1;
-	}
-
-	tx_port_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_port");
-	rxcnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rxcnt");
-	if (tx_port_map_fd < 0 || rxcnt_map_fd < 0) {
-		printf("bpf_object__find_map_fd_by_name failed\n");
-		return 1;
+	skel = xdp_redirect__open();
+	if (!skel) {
+		fprintf(stderr, "Failed to xdp_redirect__open: %s\n", strerror(errno));
+		ret = EXIT_FAIL_BPF;
+		goto end;
 	}
 
-	if (bpf_set_link_xdp_fd(ifindex_in, prog_fd, xdp_flags) < 0) {
-		printf("ERROR: link set xdp fd failed on %d\n", ifindex_in);
-		return 1;
-	}
+	skel->rodata->ifindex_out = ifindex_out;
 
-	ret = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
-	if (ret) {
-		printf("can't get prog info - %s\n", strerror(errno));
-		return ret;
+	ret = xdp_redirect__load(skel);
+	if (ret < 0) {
+		fprintf(stderr, "Failed to xdp_redirect__load: %s\n", strerror(errno));
+		ret = EXIT_FAIL_BPF;
+		goto end_destroy;
 	}
-	prog_id = info.id;
 
-	/* Loading dummy XDP prog on out-device */
-	if (bpf_set_link_xdp_fd(ifindex_out, dummy_prog_fd,
-			    (xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) {
-		printf("WARN: link set xdp fd failed on %d\n", ifindex_out);
-		ifindex_out_xdp_dummy_attached = false;
+	ret = sample_init(skel, mask);
+	if (ret < 0) {
+		fprintf(stderr, "Failed to initialize sample: %s\n", strerror(-ret));
+		ret = EXIT_FAIL;
+		goto end_destroy;
 	}
 
-	memset(&info, 0, sizeof(info));
-	ret = bpf_obj_get_info_by_fd(dummy_prog_fd, &info, &info_len);
-	if (ret) {
-		printf("can't get prog info - %s\n", strerror(errno));
-		return ret;
-	}
-	dummy_prog_id = info.id;
+	ret = EXIT_FAIL_XDP;
+	if (sample_install_xdp(skel->progs.xdp_redirect_prog, ifindex_in,
+			       generic, force) < 0)
+		goto end_destroy;
 
-	signal(SIGINT, int_exit);
-	signal(SIGTERM, int_exit);
-
-	/* bpf redirect port */
-	ret = bpf_map_update_elem(tx_port_map_fd, &key, &ifindex_out, 0);
-	if (ret) {
-		perror("bpf_update_elem");
-		goto out;
+	/* Loading dummy XDP prog on out-device */
+	sample_install_xdp(skel->progs.xdp_redirect_dummy_prog, ifindex_out,
+			   generic, force);
+
+	safe_strncpy(str, get_driver_name(ifindex_in), sizeof(str));
+	printf("Redirecting from %s (ifindex %d; driver %s) to %s (ifindex %d; driver %s)\n",
+	       ifname_in, ifindex_in, str, ifname_out, ifindex_out, get_driver_name(ifindex_out));
+	snprintf(str, sizeof(str), "%s->%s", ifname_in, ifname_out);
+
+	ret = sample_run(interval, NULL, NULL);
+	if (ret < 0) {
+		fprintf(stderr, "Failed during sample run: %s\n", strerror(-ret));
+		ret = EXIT_FAIL;
+		goto end_destroy;
 	}
-
-	poll_stats(2, ifindex_out);
-
-out:
-	return ret;
+	ret = EXIT_OK;
+end_destroy:
+	xdp_redirect__destroy(skel);
+end:
+	sample_exit(ret);
 }
-- 
2.32.0