On Apr 24, Hangbin Liu wrote:
> This is a sample for xdp multicast. In the sample we have 3 forward
> groups and 1 exclude group. It will redirect each interface's
> packets to all the interfaces in the forward group, and exclude
> the interface in exclude map.
> 
> For more testing details, please see the test description in
> xdp_redirect_map_multi.sh.
> 
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
> ---
>  samples/bpf/Makefile                      |   3 +
>  samples/bpf/xdp_redirect_map_multi.sh     | 124 ++++++++++++++++
>  samples/bpf/xdp_redirect_map_multi_kern.c | 100 +++++++++++++
>  samples/bpf/xdp_redirect_map_multi_user.c | 170 ++++++++++++++++++++++
>  4 files changed, 397 insertions(+)
>  create mode 100755 samples/bpf/xdp_redirect_map_multi.sh
>  create mode 100644 samples/bpf/xdp_redirect_map_multi_kern.c
>  create mode 100644 samples/bpf/xdp_redirect_map_multi_user.c
> 
> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> index 424f6fe7ce38..eb7306efe85e 100644

[...]

> +
> +SEC("xdp_redirect_map_multi")
> +int xdp_redirect_map_multi_prog(struct xdp_md *ctx)
> +{
> +	u32 key, mcast_group_id, exclude_group_id;
> +	void *data_end = (void *)(long)ctx->data_end;
> +	void *data = (void *)(long)ctx->data;
> +	struct ethhdr *eth = data;
> +	int *inmap_id;
> +	u16 h_proto;
> +	u64 nh_off;
> +
> +	nh_off = sizeof(*eth);
> +	if (data + nh_off > data_end)
> +		return XDP_DROP;
> +
> +	h_proto = eth->h_proto;
> +
> +	if (h_proto == htons(ETH_P_IP))
> +		return bpf_redirect_map_multi(&forward_map_v4, &exclude_map,
> +					      BPF_F_EXCLUDE_INGRESS);

Do we need the 'BPF_F_EXCLUDE_INGRESS' here?

> +	else if (h_proto == htons(ETH_P_IPV6))
> +		return bpf_redirect_map_multi(&forward_map_v6, &exclude_map,
> +					      BPF_F_EXCLUDE_INGRESS);

ditto

> +	else
> +		return bpf_redirect_map_multi(&forward_map_all, NULL,
> +					      BPF_F_EXCLUDE_INGRESS);
> +}
> +
> +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_map_multi_user.c b/samples/bpf/xdp_redirect_map_multi_user.c
> new file mode 100644
> index 000000000000..2fcd15322201
> --- /dev/null
> +++ b/samples/bpf/xdp_redirect_map_multi_user.c
> @@ -0,0 +1,170 @@
> +/* SPDX-License-Identifier: GPL-2.0-only
> + */
> +#include <linux/bpf.h>
> +#include <linux/if_link.h>
> +#include <errno.h>
> +#include <signal.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <net/if.h>
> +#include <unistd.h>
> +#include <libgen.h>
> +
> +#include <bpf/bpf.h>
> +#include <bpf/libbpf.h>
> +
> +#define MAX_IFACE_NUM 32
> +
> +static int ifaces[MAX_IFACE_NUM] = {};
> +static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
> +
> +static void int_exit(int sig)
> +{
> +	__u32 prog_id = 0;
> +	int i;
> +
> +	for (i = 0; ifaces[i] > 0; i++) {
> +		if (bpf_get_link_xdp_id(ifaces[i], &prog_id, xdp_flags)) {
> +			printf("bpf_get_link_xdp_id failed\n");
> +			exit(1);
> +		}
> +		if (prog_id)
> +			bpf_set_link_xdp_fd(ifaces[i], -1, xdp_flags);
> +	}
> +
> +	exit(0);
> +}
> +
> +static void usage(const char *prog)
> +{
> +	fprintf(stderr,
> +		"usage: %s [OPTS] <IFNAME|IFINDEX> <IFNAME|IFINDEX> ... \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)
> +{
> +	int prog_fd, group_all, group_v4, group_v6, exclude;
> +	struct bpf_prog_load_attr prog_load_attr = {
> +		.prog_type      = BPF_PROG_TYPE_XDP,
> +	};
> +	int i, ret, opt, ifindex;
> +	char ifname[IF_NAMESIZE];
> +	struct bpf_object *obj;
> +	char filename[256];
> +
> +	while ((opt = getopt(argc, argv, "SNF")) != -1) {
> +		switch (opt) {
> +		case 'S':
> +			xdp_flags |= XDP_FLAGS_SKB_MODE;
> +			break;
> +		case 'N':
> +			/* default, set below */
> +			break;
> +		case 'F':
> +			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
> +			break;
> +		default:
> +			usage(basename(argv[0]));
> +			return 1;
> +		}
> +	}
> +
> +	if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
> +		xdp_flags |= XDP_FLAGS_DRV_MODE;
> +
> +	if (optind == argc) {
> +		printf("usage: %s <IFNAME|IFINDEX> <IFNAME|IFINDEX> ...\n", argv[0]);
> +		return 1;
> +	}
> +
> +	printf("Get interfaces");
> +	for (i = 0; i < MAX_IFACE_NUM && argv[optind + i]; i ++) {
> +		ifaces[i] = if_nametoindex(argv[optind + i]);
> +		if (!ifaces[i])
> +			ifaces[i] = strtoul(argv[optind + i], NULL, 0);
> +		if (!if_indextoname(ifaces[i], ifname)) {
> +			perror("Invalid interface name or i");
> +			return 1;
> +		}
> +		printf(" %d", ifaces[i]);
> +	}
> +	printf("\n");
> +
> +	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;
> +
> +	group_all = bpf_object__find_map_fd_by_name(obj, "forward_map_all");
> +	group_v4 = bpf_object__find_map_fd_by_name(obj, "forward_map_v4");
> +	group_v6 = bpf_object__find_map_fd_by_name(obj, "forward_map_v6");
> +	exclude = bpf_object__find_map_fd_by_name(obj, "exclude_map");
> +
> +	if (group_all < 0 || group_v4 < 0 || group_v6 < 0 || exclude < 0) {
> +		printf("bpf_object__find_map_fd_by_name failed\n");
> +		return 1;
> +	}
> +
> +	signal(SIGINT, int_exit);
> +	signal(SIGTERM, int_exit);
> +
> +	/* Init forward multicast groups and exclude group */
> +	for (i = 0; ifaces[i] > 0; i++) {
> +		ifindex = ifaces[i];
> +
> +		/* Add all the interfaces to group all */
> +		ret = bpf_map_update_elem(group_all, &ifindex, &ifindex, 0);
> +		if (ret) {
> +			perror("bpf_map_update_elem");
> +			goto err_out;
> +		}
> +
> +		/* For testing: remove the 2nd interfaces from group v4 */
> +		if (i != 1) {
> +			ret = bpf_map_update_elem(group_v4, &ifindex, &ifindex, 0);
> +			if (ret) {
> +				perror("bpf_map_update_elem");
> +				goto err_out;
> +			}
> +		}
> +
> +		/* For testing: remove the 1st interfaces from group v6 */
> +		if (i != 0) {
> +			ret = bpf_map_update_elem(group_v6, &ifindex, &ifindex, 0);
> +			if (ret) {
> +				perror("bpf_map_update_elem");
> +				goto err_out;
> +			}
> +		}
> +
> +		/* For testing: add the 3rd interfaces to exclude map */
> +		if (i == 2) {
> +			ret = bpf_map_update_elem(exclude, &ifindex, &ifindex, 0);
> +			if (ret) {
> +				perror("bpf_map_update_elem");
> +				goto err_out;
> +			}
> +		}
> +
> +		/* bind prog_fd to each interface */
> +		ret = bpf_set_link_xdp_fd(ifindex, prog_fd, xdp_flags);
> +		if (ret) {
> +			printf("Set xdp fd failed on %d\n", ifindex);
> +			goto err_out;
> +		}
> +
> +	}
> +
> +	sleep(600);
> +	return 0;
> +
> +err_out:
> +	return 1;
> +}
> -- 
> 2.19.2
>