v4.19.13 snapshot.
diff --git a/samples/bpf/test_cgrp2_attach.c b/samples/bpf/test_cgrp2_attach.c
new file mode 100644
index 0000000..20fbd12
--- /dev/null
+++ b/samples/bpf/test_cgrp2_attach.c
@@ -0,0 +1,172 @@
+/* eBPF example program:
+ *
+ * - Creates arraymap in kernel with 4 bytes keys and 8 byte values
+ *
+ * - Loads eBPF program
+ *
+ * The eBPF program accesses the map passed in to store two pieces of
+ * information. The number of invocations of the program, which maps
+ * to the number of packets received, is stored to key 0. Key 1 is
+ * incremented on each iteration by the number of bytes stored in
+ * the skb.
+ *
+ * - Attaches the new program to a cgroup using BPF_PROG_ATTACH
+ *
+ * - Every second, reads map[0] and map[1] to see how many bytes and
+ * packets were seen on any socket of tasks in the given cgroup.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include <linux/bpf.h>
+#include <bpf/bpf.h>
+
+#include "bpf_insn.h"
+
+enum {
+ MAP_KEY_PACKETS,
+ MAP_KEY_BYTES,
+};
+
+char bpf_log_buf[BPF_LOG_BUF_SIZE];
+
+static int prog_load(int map_fd, int verdict)
+{
+ struct bpf_insn prog[] = {
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), /* save r6 so it's not clobbered by BPF_CALL */
+
+ /* Count packets */
+ BPF_MOV64_IMM(BPF_REG_0, MAP_KEY_PACKETS), /* r0 = 0 */
+ BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */
+ BPF_LD_MAP_FD(BPF_REG_1, map_fd), /* load map fd to r1 */
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+ BPF_MOV64_IMM(BPF_REG_1, 1), /* r1 = 1 */
+ BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */
+
+ /* Count bytes */
+ BPF_MOV64_IMM(BPF_REG_0, MAP_KEY_BYTES), /* r0 = 1 */
+ BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */
+ BPF_LD_MAP_FD(BPF_REG_1, map_fd),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6, offsetof(struct __sk_buff, len)), /* r1 = skb->len */
+ BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */
+
+ BPF_MOV64_IMM(BPF_REG_0, verdict), /* r0 = verdict */
+ BPF_EXIT_INSN(),
+ };
+ size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn);
+
+ return bpf_load_program(BPF_PROG_TYPE_CGROUP_SKB,
+ prog, insns_cnt, "GPL", 0,
+ bpf_log_buf, BPF_LOG_BUF_SIZE);
+}
+
+static int usage(const char *argv0)
+{
+ printf("Usage: %s [-d] [-D] <cg-path> <egress|ingress>\n", argv0);
+ printf(" -d Drop Traffic\n");
+ printf(" -D Detach filter, and exit\n");
+ return EXIT_FAILURE;
+}
+
+static int attach_filter(int cg_fd, int type, int verdict)
+{
+ int prog_fd, map_fd, ret, key;
+ long long pkt_cnt, byte_cnt;
+
+ map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY,
+ sizeof(key), sizeof(byte_cnt),
+ 256, 0);
+ if (map_fd < 0) {
+ printf("Failed to create map: '%s'\n", strerror(errno));
+ return EXIT_FAILURE;
+ }
+
+ prog_fd = prog_load(map_fd, verdict);
+ printf("Output from kernel verifier:\n%s\n-------\n", bpf_log_buf);
+
+ if (prog_fd < 0) {
+ printf("Failed to load prog: '%s'\n", strerror(errno));
+ return EXIT_FAILURE;
+ }
+
+ ret = bpf_prog_attach(prog_fd, cg_fd, type, 0);
+ if (ret < 0) {
+ printf("Failed to attach prog to cgroup: '%s'\n",
+ strerror(errno));
+ return EXIT_FAILURE;
+ }
+ while (1) {
+ key = MAP_KEY_PACKETS;
+ assert(bpf_map_lookup_elem(map_fd, &key, &pkt_cnt) == 0);
+
+ key = MAP_KEY_BYTES;
+ assert(bpf_map_lookup_elem(map_fd, &key, &byte_cnt) == 0);
+
+ printf("cgroup received %lld packets, %lld bytes\n",
+ pkt_cnt, byte_cnt);
+ sleep(1);
+ }
+
+ return EXIT_SUCCESS;
+}
+
+int main(int argc, char **argv)
+{
+ int detach_only = 0, verdict = 1;
+ enum bpf_attach_type type;
+ int opt, cg_fd, ret;
+
+ while ((opt = getopt(argc, argv, "Dd")) != -1) {
+ switch (opt) {
+ case 'd':
+ verdict = 0;
+ break;
+ case 'D':
+ detach_only = 1;
+ break;
+ default:
+ return usage(argv[0]);
+ }
+ }
+
+ if (argc - optind < 2)
+ return usage(argv[0]);
+
+ if (strcmp(argv[optind + 1], "ingress") == 0)
+ type = BPF_CGROUP_INET_INGRESS;
+ else if (strcmp(argv[optind + 1], "egress") == 0)
+ type = BPF_CGROUP_INET_EGRESS;
+ else
+ return usage(argv[0]);
+
+ cg_fd = open(argv[optind], O_DIRECTORY | O_RDONLY);
+ if (cg_fd < 0) {
+ printf("Failed to open cgroup path: '%s'\n", strerror(errno));
+ return EXIT_FAILURE;
+ }
+
+ if (detach_only) {
+ ret = bpf_prog_detach(cg_fd, type);
+ printf("bpf_prog_detach() returned '%s' (%d)\n",
+ strerror(errno), errno);
+ } else
+ ret = attach_filter(cg_fd, type, verdict);
+
+ return ret;
+}