361 lines
		
	
	
		
			8.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			361 lines
		
	
	
		
			8.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
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/* Copyright (c) 2019 Netronome Systems, Inc. */
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#include <errno.h>
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#include <fcntl.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <net/if.h>
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#include <sys/utsname.h>
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#include <linux/btf.h>
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#include <linux/filter.h>
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#include <linux/kernel.h>
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#include "bpf.h"
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#include "libbpf.h"
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#include "libbpf_internal.h"
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static bool grep(const char *buffer, const char *pattern)
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{
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	return !!strstr(buffer, pattern);
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}
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static int get_vendor_id(int ifindex)
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{
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	char ifname[IF_NAMESIZE], path[64], buf[8];
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	ssize_t len;
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	int fd;
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	if (!if_indextoname(ifindex, ifname))
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		return -1;
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	snprintf(path, sizeof(path), "/sys/class/net/%s/device/vendor", ifname);
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	fd = open(path, O_RDONLY);
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	if (fd < 0)
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		return -1;
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	len = read(fd, buf, sizeof(buf));
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	close(fd);
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	if (len < 0)
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		return -1;
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	if (len >= (ssize_t)sizeof(buf))
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		return -1;
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	buf[len] = '\0';
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	return strtol(buf, NULL, 0);
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}
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static int get_kernel_version(void)
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{
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	int version, subversion, patchlevel;
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	struct utsname utsn;
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	/* Return 0 on failure, and attempt to probe with empty kversion */
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	if (uname(&utsn))
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		return 0;
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	if (sscanf(utsn.release, "%d.%d.%d",
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		   &version, &subversion, &patchlevel) != 3)
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		return 0;
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	return (version << 16) + (subversion << 8) + patchlevel;
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}
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static void
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probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns,
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	   size_t insns_cnt, char *buf, size_t buf_len, __u32 ifindex)
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{
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	struct bpf_load_program_attr xattr = {};
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	int fd;
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	switch (prog_type) {
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	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
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		xattr.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
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		break;
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	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
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		xattr.expected_attach_type = BPF_CGROUP_GETSOCKOPT;
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		break;
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	case BPF_PROG_TYPE_SK_LOOKUP:
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		xattr.expected_attach_type = BPF_SK_LOOKUP;
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		break;
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	case BPF_PROG_TYPE_KPROBE:
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		xattr.kern_version = get_kernel_version();
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		break;
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	case BPF_PROG_TYPE_UNSPEC:
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	case BPF_PROG_TYPE_SOCKET_FILTER:
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	case BPF_PROG_TYPE_SCHED_CLS:
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	case BPF_PROG_TYPE_SCHED_ACT:
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	case BPF_PROG_TYPE_TRACEPOINT:
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	case BPF_PROG_TYPE_XDP:
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	case BPF_PROG_TYPE_PERF_EVENT:
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	case BPF_PROG_TYPE_CGROUP_SKB:
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	case BPF_PROG_TYPE_CGROUP_SOCK:
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	case BPF_PROG_TYPE_LWT_IN:
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	case BPF_PROG_TYPE_LWT_OUT:
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	case BPF_PROG_TYPE_LWT_XMIT:
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	case BPF_PROG_TYPE_SOCK_OPS:
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	case BPF_PROG_TYPE_SK_SKB:
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	case BPF_PROG_TYPE_CGROUP_DEVICE:
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	case BPF_PROG_TYPE_SK_MSG:
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	case BPF_PROG_TYPE_RAW_TRACEPOINT:
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	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
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	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
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	case BPF_PROG_TYPE_LIRC_MODE2:
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	case BPF_PROG_TYPE_SK_REUSEPORT:
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	case BPF_PROG_TYPE_FLOW_DISSECTOR:
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	case BPF_PROG_TYPE_CGROUP_SYSCTL:
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	case BPF_PROG_TYPE_TRACING:
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	case BPF_PROG_TYPE_STRUCT_OPS:
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	case BPF_PROG_TYPE_EXT:
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	case BPF_PROG_TYPE_LSM:
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	default:
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		break;
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	}
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	xattr.prog_type = prog_type;
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	xattr.insns = insns;
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	xattr.insns_cnt = insns_cnt;
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	xattr.license = "GPL";
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	xattr.prog_ifindex = ifindex;
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	fd = bpf_load_program_xattr(&xattr, buf, buf_len);
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	if (fd >= 0)
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		close(fd);
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}
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bool bpf_probe_prog_type(enum bpf_prog_type prog_type, __u32 ifindex)
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{
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	struct bpf_insn insns[2] = {
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		BPF_MOV64_IMM(BPF_REG_0, 0),
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		BPF_EXIT_INSN()
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	};
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	if (ifindex && prog_type == BPF_PROG_TYPE_SCHED_CLS)
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		/* nfp returns -EINVAL on exit(0) with TC offload */
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		insns[0].imm = 2;
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	errno = 0;
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	probe_load(prog_type, insns, ARRAY_SIZE(insns), NULL, 0, ifindex);
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	return errno != EINVAL && errno != EOPNOTSUPP;
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}
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int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
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			 const char *str_sec, size_t str_len)
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{
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	struct btf_header hdr = {
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		.magic = BTF_MAGIC,
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		.version = BTF_VERSION,
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		.hdr_len = sizeof(struct btf_header),
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		.type_len = types_len,
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		.str_off = types_len,
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		.str_len = str_len,
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	};
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	int btf_fd, btf_len;
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	__u8 *raw_btf;
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	btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len;
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	raw_btf = malloc(btf_len);
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	if (!raw_btf)
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		return -ENOMEM;
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	memcpy(raw_btf, &hdr, sizeof(hdr));
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	memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len);
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	memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len);
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	btf_fd = bpf_load_btf(raw_btf, btf_len, NULL, 0, false);
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	free(raw_btf);
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	return btf_fd;
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}
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static int load_local_storage_btf(void)
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{
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	const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
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	/* struct bpf_spin_lock {
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	 *   int val;
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	 * };
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	 * struct val {
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	 *   int cnt;
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	 *   struct bpf_spin_lock l;
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	 * };
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	 */
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	__u32 types[] = {
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		/* int */
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		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
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		/* struct bpf_spin_lock */                      /* [2] */
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		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),
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		BTF_MEMBER_ENC(15, 1, 0), /* int val; */
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		/* struct val */                                /* [3] */
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		BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8),
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		BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
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		BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
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	};
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	return libbpf__load_raw_btf((char *)types, sizeof(types),
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				     strs, sizeof(strs));
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}
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bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex)
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{
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	int key_size, value_size, max_entries, map_flags;
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	__u32 btf_key_type_id = 0, btf_value_type_id = 0;
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	struct bpf_create_map_attr attr = {};
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	int fd = -1, btf_fd = -1, fd_inner;
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	key_size	= sizeof(__u32);
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	value_size	= sizeof(__u32);
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	max_entries	= 1;
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	map_flags	= 0;
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	switch (map_type) {
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	case BPF_MAP_TYPE_STACK_TRACE:
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		value_size	= sizeof(__u64);
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		break;
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	case BPF_MAP_TYPE_LPM_TRIE:
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		key_size	= sizeof(__u64);
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		value_size	= sizeof(__u64);
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		map_flags	= BPF_F_NO_PREALLOC;
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		break;
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	case BPF_MAP_TYPE_CGROUP_STORAGE:
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	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
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		key_size	= sizeof(struct bpf_cgroup_storage_key);
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		value_size	= sizeof(__u64);
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		max_entries	= 0;
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		break;
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	case BPF_MAP_TYPE_QUEUE:
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	case BPF_MAP_TYPE_STACK:
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		key_size	= 0;
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		break;
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	case BPF_MAP_TYPE_SK_STORAGE:
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	case BPF_MAP_TYPE_INODE_STORAGE:
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	case BPF_MAP_TYPE_TASK_STORAGE:
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		btf_key_type_id = 1;
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		btf_value_type_id = 3;
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		value_size = 8;
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		max_entries = 0;
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		map_flags = BPF_F_NO_PREALLOC;
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		btf_fd = load_local_storage_btf();
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		if (btf_fd < 0)
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			return false;
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		break;
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	case BPF_MAP_TYPE_RINGBUF:
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		key_size = 0;
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		value_size = 0;
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		max_entries = 4096;
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		break;
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	case BPF_MAP_TYPE_UNSPEC:
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	case BPF_MAP_TYPE_HASH:
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	case BPF_MAP_TYPE_ARRAY:
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	case BPF_MAP_TYPE_PROG_ARRAY:
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	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
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	case BPF_MAP_TYPE_PERCPU_HASH:
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	case BPF_MAP_TYPE_PERCPU_ARRAY:
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	case BPF_MAP_TYPE_CGROUP_ARRAY:
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	case BPF_MAP_TYPE_LRU_HASH:
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	case BPF_MAP_TYPE_LRU_PERCPU_HASH:
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	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
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	case BPF_MAP_TYPE_HASH_OF_MAPS:
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	case BPF_MAP_TYPE_DEVMAP:
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	case BPF_MAP_TYPE_DEVMAP_HASH:
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	case BPF_MAP_TYPE_SOCKMAP:
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	case BPF_MAP_TYPE_CPUMAP:
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	case BPF_MAP_TYPE_XSKMAP:
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	case BPF_MAP_TYPE_SOCKHASH:
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	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
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	case BPF_MAP_TYPE_STRUCT_OPS:
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	default:
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		break;
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	}
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	if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
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	    map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
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		/* TODO: probe for device, once libbpf has a function to create
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		 * map-in-map for offload
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		 */
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		if (ifindex)
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			return false;
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		fd_inner = bpf_create_map(BPF_MAP_TYPE_HASH,
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					  sizeof(__u32), sizeof(__u32), 1, 0);
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		if (fd_inner < 0)
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			return false;
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		fd = bpf_create_map_in_map(map_type, NULL, sizeof(__u32),
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					   fd_inner, 1, 0);
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		close(fd_inner);
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	} else {
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		/* Note: No other restriction on map type probes for offload */
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		attr.map_type = map_type;
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		attr.key_size = key_size;
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		attr.value_size = value_size;
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		attr.max_entries = max_entries;
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		attr.map_flags = map_flags;
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		attr.map_ifindex = ifindex;
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		if (btf_fd >= 0) {
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			attr.btf_fd = btf_fd;
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			attr.btf_key_type_id = btf_key_type_id;
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			attr.btf_value_type_id = btf_value_type_id;
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		}
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		fd = bpf_create_map_xattr(&attr);
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	}
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	if (fd >= 0)
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		close(fd);
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	if (btf_fd >= 0)
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		close(btf_fd);
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	return fd >= 0;
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}
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bool bpf_probe_helper(enum bpf_func_id id, enum bpf_prog_type prog_type,
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		      __u32 ifindex)
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{
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	struct bpf_insn insns[2] = {
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		BPF_EMIT_CALL(id),
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		BPF_EXIT_INSN()
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	};
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	char buf[4096] = {};
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	bool res;
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	probe_load(prog_type, insns, ARRAY_SIZE(insns), buf, sizeof(buf),
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		   ifindex);
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	res = !grep(buf, "invalid func ") && !grep(buf, "unknown func ");
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	if (ifindex) {
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		switch (get_vendor_id(ifindex)) {
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		case 0x19ee: /* Netronome specific */
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			res = res && !grep(buf, "not supported by FW") &&
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				!grep(buf, "unsupported function id");
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			break;
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		default:
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			break;
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		}
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	}
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	return res;
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}
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/*
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 * Probe for availability of kernel commit (5.3):
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 *
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 * c04c0d2b968a ("bpf: increase complexity limit and maximum program size")
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 */
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bool bpf_probe_large_insn_limit(__u32 ifindex)
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{
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	struct bpf_insn insns[BPF_MAXINSNS + 1];
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	int i;
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	for (i = 0; i < BPF_MAXINSNS; i++)
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		insns[i] = BPF_MOV64_IMM(BPF_REG_0, 1);
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	insns[BPF_MAXINSNS] = BPF_EXIT_INSN();
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	errno = 0;
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	probe_load(BPF_PROG_TYPE_SCHED_CLS, insns, ARRAY_SIZE(insns), NULL, 0,
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		   ifindex);
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	return errno != E2BIG && errno != EINVAL;
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}
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