Commit 54af769d authored by Kumar Kartikeya Dwivedi's avatar Kumar Kartikeya Dwivedi Committed by Alexei Starovoitov
Browse files

samples: bpf: Convert xdp_redirect_map_kern.o to XDP samples helper 



Also update it to use consistent SEC("xdp") and SEC("xdp_devmap")
naming, and use global variable instead of BPF map for copying the mac
address.

Signed-off-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-20-memxor@gmail.com
parent e531a220

samples/bpf/Makefile

+4 −2
Original line number Diff line number Diff line
@@ -163,7 +163,6 @@ 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_map_kern.o

always-y += xdp_redirect_map_multi_kern.o

always-y += xdp_rxq_info_kern.o

always-y += xdp2skb_meta_kern.o
@@ -357,6 +356,7 @@ endef 
CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))



$(obj)/xdp_redirect_cpu.bpf.o: $(obj)/xdp_sample.bpf.o

$(obj)/xdp_redirect_map.bpf.o: $(obj)/xdp_sample.bpf.o

$(obj)/xdp_redirect.bpf.o: $(obj)/xdp_sample.bpf.o

$(obj)/xdp_monitor.bpf.o: $(obj)/xdp_sample.bpf.o
@@ -368,10 +368,12 @@ $(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_redirect_cpu.skel.h xdp_redirect.skel.h xdp_monitor.skel.h

LINKED_SKELS := xdp_redirect_cpu.skel.h xdp_redirect_map.skel.h \

		 xdp_redirect.skel.h xdp_monitor.skel.h

clean-files += $(LINKED_SKELS)



xdp_redirect_cpu.skel.h-deps := xdp_redirect_cpu.bpf.o xdp_sample.bpf.o

xdp_redirect_map.skel.h-deps := xdp_redirect_map.bpf.o xdp_sample.bpf.o

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

samples/bpf/xdp_redirect_map_kern.c→samples/bpf/xdp_redirect_map.bpf.c

+21 −68
Original line number Diff line number Diff line
@@ -10,14 +10,10 @@ 
 * 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>



#include "vmlinux.h"

#include "xdp_sample.bpf.h"

#include "xdp_sample_shared.h"



/* The 2nd xdp prog on egress does not support skb mode, so we define two

 * maps, tx_port_general and tx_port_native.
@@ -26,114 +22,71 @@ struct { 
	__uint(type, BPF_MAP_TYPE_DEVMAP);

	__uint(key_size, sizeof(int));

	__uint(value_size, sizeof(int));

	__uint(max_entries, 100);

	__uint(max_entries, 1);

} tx_port_general SEC(".maps");



struct {

	__uint(type, BPF_MAP_TYPE_DEVMAP);

	__uint(key_size, sizeof(int));

	__uint(value_size, sizeof(struct bpf_devmap_val));

	__uint(max_entries, 100);

} tx_port_native 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");



/* map to store egress interface mac address */

struct {

	__uint(type, BPF_MAP_TYPE_ARRAY);

	__type(key, u32);

	__type(value, __be64);

	__uint(max_entries, 1);

} tx_mac SEC(".maps");

} tx_port_native 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];

}

/* store egress interface mac address */

const volatile char tx_mac_addr[ETH_ALEN];



static __always_inline int xdp_redirect_map(struct xdp_md *ctx, void *redirect_map)

{

	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;

	int rc = XDP_DROP;

	long *value;

	u32 key = 0;

	struct datarec *rec;

	u64 nh_off;

	int vport;



	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;

		return XDP_DROP;



	rec = bpf_map_lookup_elem(&rx_cnt, &key);

	if (!rec)

		return XDP_PASS;

	NO_TEAR_INC(rec->processed);

	swap_src_dst_mac(data);



	/* send packet out physical port */

	return bpf_redirect_map(redirect_map, vport, 0);

	return bpf_redirect_map(redirect_map, 0, 0);

}



SEC("xdp_redirect_general")

SEC("xdp")

int xdp_redirect_map_general(struct xdp_md *ctx)

{

	return xdp_redirect_map(ctx, &tx_port_general);

}



SEC("xdp_redirect_native")

SEC("xdp")

int xdp_redirect_map_native(struct xdp_md *ctx)

{

	return xdp_redirect_map(ctx, &tx_port_native);

}



SEC("xdp_devmap/map_prog")

SEC("xdp_devmap/egress")

int xdp_redirect_map_egress(struct xdp_md *ctx)

{

	void *data_end = (void *)(long)ctx->data_end;

	void *data = (void *)(long)ctx->data;

	struct ethhdr *eth = data;

	__be64 *mac;

	u32 key = 0;

	u64 nh_off;



	nh_off = sizeof(*eth);

	if (data + nh_off > data_end)

		return XDP_DROP;



	mac = bpf_map_lookup_elem(&tx_mac, &key);

	if (mac)

		__builtin_memcpy(eth->h_source, mac, ETH_ALEN);

	__builtin_memcpy(eth->h_source, (const char *)tx_mac_addr, ETH_ALEN);



	return XDP_PASS;

}



/* Redirect require an XDP bpf_prog loaded on the TX device */

SEC("xdp_redirect_dummy")

SEC("xdp")

int xdp_redirect_dummy_prog(struct xdp_md *ctx)

{

	return XDP_PASS;