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libbpf.c
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/*
* Copyright (c) 2015 PLUMgrid, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include "libbpf.h"
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <libgen.h>
#include <limits.h>
#include <linux/bpf.h>
#include <linux/bpf_common.h>
#include <linux/if_alg.h>
#include <linux/if_packet.h>
#include <linux/perf_event.h>
#include <linux/pkt_cls.h>
#include <linux/rtnetlink.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/unistd.h>
#include <linux/version.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <sched.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/vfs.h>
#include <unistd.h>
#include "bcc_zip.h"
#include "perf_reader.h"
// TODO: Remove this when CentOS 6 support is not needed anymore
#include "setns.h"
#include "bcc_libbpf_inc.h"
// TODO: remove these defines when linux-libc-dev exports them properly
#ifndef __NR_bpf
#if defined(__powerpc64__)
#define __NR_bpf 361
#elif defined(__s390x__)
#define __NR_bpf 351
#elif defined(__aarch64__)
#define __NR_bpf 280
#else
#define __NR_bpf 321
#endif
#endif
#ifndef SO_ATTACH_BPF
#define SO_ATTACH_BPF 50
#endif
#ifndef PERF_EVENT_IOC_SET_BPF
#define PERF_EVENT_IOC_SET_BPF _IOW('$', 8, __u32)
#endif
#ifndef PERF_FLAG_FD_CLOEXEC
#define PERF_FLAG_FD_CLOEXEC (1UL << 3)
#endif
// TODO: Remove this when CentOS 6 support is not needed anymore
#ifndef AF_ALG
#define AF_ALG 38
#endif
#ifndef min
#define min(x, y) ((x) < (y) ? (x) : (y))
#endif
#define UNUSED(expr) do { (void)(expr); } while (0)
#define PERF_UPROBE_REF_CTR_OFFSET_SHIFT 32
#ifndef BPF_FS_MAGIC
#define BPF_FS_MAGIC 0xcafe4a11
#endif
struct bpf_helper {
char *name;
char *required_version;
};
static struct bpf_helper helpers[] = {
{"map_lookup_elem", "3.19"},
{"map_update_elem", "3.19"},
{"map_delete_elem", "3.19"},
{"probe_read", "4.1"},
{"ktime_get_ns", "4.1"},
{"trace_printk", "4.1"},
{"get_prandom_u32", "4.1"},
{"get_smp_processor_id", "4.1"},
{"skb_store_bytes", "4.1"},
{"l3_csum_replace", "4.1"},
{"l4_csum_replace", "4.1"},
{"tail_call", "4.2"},
{"clone_redirect", "4.2"},
{"get_current_pid_tgid", "4.2"},
{"get_current_uid_gid", "4.2"},
{"get_current_comm", "4.2"},
{"get_cgroup_classid", "4.3"},
{"skb_vlan_push", "4.3"},
{"skb_vlan_pop", "4.3"},
{"skb_get_tunnel_key", "4.3"},
{"skb_set_tunnel_key", "4.3"},
{"perf_event_read", "4.3"},
{"redirect", "4.4"},
{"get_route_realm", "4.4"},
{"perf_event_output", "4.4"},
{"skb_load_bytes", "4.5"},
{"get_stackid", "4.6"},
{"csum_diff", "4.6"},
{"skb_get_tunnel_opt", "4.6"},
{"skb_set_tunnel_opt", "4.6"},
{"skb_change_proto", "4.8"},
{"skb_change_type", "4.8"},
{"skb_under_cgroup", "4.8"},
{"get_hash_recalc", "4.8"},
{"get_current_task", "4.8"},
{"probe_write_user", "4.8"},
{"current_task_under_cgroup", "4.9"},
{"skb_change_tail", "4.9"},
{"skb_pull_data", "4.9"},
{"csum_update", "4.9"},
{"set_hash_invalid", "4.9"},
{"get_numa_node_id", "4.10"},
{"skb_change_head", "4.10"},
{"xdp_adjust_head", "4.10"},
{"probe_read_str", "4.11"},
{"get_socket_cookie", "4.12"},
{"get_socket_uid", "4.12"},
{"set_hash", "4.13"},
{"setsockopt", "4.13"},
{"skb_adjust_room", "4.13"},
{"redirect_map", "4.14"},
{"sk_redirect_map", "4.14"},
{"sock_map_update", "4.14"},
{"xdp_adjust_meta", "4.15"},
{"perf_event_read_value", "4.15"},
{"perf_prog_read_value", "4.15"},
{"getsockopt", "4.15"},
{"override_return", "4.16"},
{"sock_ops_cb_flags_set", "4.16"},
{"msg_redirect_map", "4.17"},
{"msg_apply_bytes", "4.17"},
{"msg_cork_bytes", "4.17"},
{"msg_pull_data", "4.17"},
{"bind", "4.17"},
{"xdp_adjust_tail", "4.18"},
{"skb_get_xfrm_state", "4.18"},
{"get_stack", "4.18"},
{"skb_load_bytes_relative", "4.18"},
{"fib_lookup", "4.18"},
{"sock_hash_update", "4.18"},
{"msg_redirect_hash", "4.18"},
{"sk_redirect_hash", "4.18"},
{"lwt_push_encap", "4.18"},
{"lwt_seg6_store_bytes", "4.18"},
{"lwt_seg6_adjust_srh", "4.18"},
{"lwt_seg6_action", "4.18"},
{"rc_repeat", "4.18"},
{"rc_keydown", "4.18"},
{"skb_cgroup_id", "4.18"},
{"get_current_cgroup_id", "4.18"},
{"get_local_storage", "4.19"},
{"sk_select_reuseport", "4.19"},
{"skb_ancestor_cgroup_id", "4.19"},
{"sk_lookup_tcp", "4.20"},
{"sk_lookup_udp", "4.20"},
{"sk_release", "4.20"},
{"map_push_elem", "4.20"},
{"map_pop_elem", "4.20"},
{"map_peak_elem", "4.20"},
{"msg_push_data", "4.20"},
{"msg_pop_data", "5.0"},
{"rc_pointer_rel", "5.0"},
{"spin_lock", "5.1"},
{"spin_unlock", "5.1"},
{"sk_fullsock", "5.1"},
{"tcp_sock", "5.1"},
{"skb_ecn_set_ce", "5.1"},
{"get_listener_sock", "5.1"},
{"skc_lookup_tcp", "5.2"},
{"tcp_check_syncookie", "5.2"},
{"sysctl_get_name", "5.2"},
{"sysctl_get_current_value", "5.2"},
{"sysctl_get_new_value", "5.2"},
{"sysctl_set_new_value", "5.2"},
{"strtol", "5.2"},
{"strtoul", "5.2"},
{"sk_storage_get", "5.2"},
{"sk_storage_delete", "5.2"},
{"send_signal", "5.3"},
{"tcp_gen_syncookie", "5.3"},
{"skb_output", "5.5"},
{"probe_read_user", "5.5"},
{"probe_read_kernel", "5.5"},
{"probe_read_user_str", "5.5"},
{"probe_read_kernel_str", "5.5"},
{"tcp_send_ack", "5.5"},
{"send_signal_thread", "5.5"},
{"jiffies64", "5.5"},
{"read_branch_records", "5.6"},
{"get_ns_current_pid_tgid", "5.6"},
{"xdp_output", "5.6"},
{"get_netns_cookie", "5.6"},
{"get_current_ancestor_cgroup_id", "5.6"},
{"sk_assign", "5.6"},
{"ktime_get_boot_ns", "5.7"},
{"seq_printf", "5.7"},
{"seq_write", "5.7"},
{"sk_cgroup_id", "5.7"},
{"sk_ancestor_cgroup_id", "5.7"},
{"csum_level", "5.7"},
{"ringbuf_output", "5.8"},
{"ringbuf_reserve", "5.8"},
{"ringbuf_submit", "5.8"},
{"ringbuf_discard", "5.8"},
{"ringbuf_query", "5.8"},
{"skc_to_tcp6_sock", "5.9"},
{"skc_to_tcp_sock", "5.9"},
{"skc_to_tcp_timewait_sock", "5.9"},
{"skc_to_tcp_request_sock", "5.9"},
{"skc_to_udp6_sock", "5.9"},
{"get_task_stack", "5.9"},
{"load_hdr_opt", "5.10"},
{"store_hdr_opt", "5.10"},
{"reserve_hdr_opt", "5.10"},
{"inode_storage_get", "5.10"},
{"inode_storage_delete", "5.10"},
{"d_path", "5.10"},
{"copy_from_user", "5.10"},
{"snprintf_btf", "5.10"},
{"seq_printf_btf", "5.10"},
{"skb_cgroup_classid", "5.10"},
{"redirect_neigh", "5.10"},
{"per_cpu_ptr", "5.10"},
{"this_cpu_ptr", "5.10"},
{"redirect_peer", "5.10"},
{"task_storage_get", "5.11"},
{"task_storage_delete", "5.11"},
{"get_current_task_btf", "5.11"},
{"bprm_opts_set", "5.11"},
{"ktime_get_coarse_ns", "5.11"},
{"ima_inode_hash", "5.11"},
{"sock_from_file", "5.11"},
{"check_mtu", "5.12"},
{"for_each_map_elem", "5.13"},
{"snprintf", "5.13"},
{"sys_bpf", "5.14"},
{"btf_find_by_name_kind", "5.14"},
{"sys_close", "5.14"},
{"timer_init", "5.15"},
{"timer_set_callback", "5.15"},
{"timer_start", "5.15"},
{"timer_cancel", "5.15"},
{"get_func_ip", "5.15"},
{"get_attach_cookie", "5.15"},
{"task_pt_regs", "5.15"},
{"get_branch_snapshot", "5.16"},
{"trace_vprintk", "5.16"},
{"skc_to_unix_sock", "5.16"},
{"kallsyms_lookup_name", "5.16"},
{"find_vma", "5.17"},
{"loop", "5.17"},
{"strncmp", "5.17"},
{"get_func_arg", "5.17"},
{"get_func_ret", "5.17"},
{"get_func_ret", "5.17"},
{"get_retval", "5.18"},
{"set_retval", "5.18"},
{"xdp_get_buff_len", "5.18"},
{"xdp_load_bytes", "5.18"},
{"xdp_store_bytes", "5.18"},
{"copy_from_user_task", "5.18"},
{"skb_set_tstamp", "5.18"},
{"ima_file_hash", "5.18"},
{"kptr_xchg", "5.19"},
{"map_lookup_percpu_elem", "5.19"},
{"skc_to_mptcp_sock", "5.19"},
{"dynptr_from_mem", "5.19"},
{"ringbuf_reserve_dynptr", "5.19"},
{"ringbuf_submit_dynptr", "5.19"},
{"ringbuf_discard_dynptr", "5.19"},
{"dynptr_read", "5.19"},
{"dynptr_write", "5.19"},
{"dynptr_data", "5.19"},
{"tcp_raw_gen_syncookie_ipv4", "6.0"},
{"tcp_raw_gen_syncookie_ipv6", "6.0"},
{"tcp_raw_check_syncookie_ipv4", "6.0"},
{"tcp_raw_check_syncookie_ipv6", "6.0"},
{"ktime_get_tai_ns", "6.1"},
{"user_ringbuf_drain", "6.1"},
{"cgrp_storage_get", "6.2"},
{"cgrp_storage_delete", "6.2"},
};
static uint64_t ptr_to_u64(void *ptr)
{
return (uint64_t) (unsigned long) ptr;
}
static int libbpf_bpf_map_create(struct bcc_create_map_attr *create_attr)
{
LIBBPF_OPTS(bpf_map_create_opts, p);
p.map_flags = create_attr->map_flags;
p.numa_node = create_attr->numa_node;
p.btf_fd = create_attr->btf_fd;
p.btf_key_type_id = create_attr->btf_key_type_id;
p.btf_value_type_id = create_attr->btf_value_type_id;
p.map_ifindex = create_attr->map_ifindex;
if (create_attr->map_type == BPF_MAP_TYPE_STRUCT_OPS)
p.btf_vmlinux_value_type_id = create_attr->btf_vmlinux_value_type_id;
else
p.inner_map_fd = create_attr->inner_map_fd;
return bpf_map_create(create_attr->map_type, create_attr->name, create_attr->key_size,
create_attr->value_size, create_attr->max_entries, &p);
}
int bcc_create_map_xattr(struct bcc_create_map_attr *attr, bool allow_rlimit)
{
unsigned name_len = attr->name ? strlen(attr->name) : 0;
char map_name[BPF_OBJ_NAME_LEN] = {};
memcpy(map_name, attr->name, min(name_len, BPF_OBJ_NAME_LEN - 1));
attr->name = map_name;
int ret = libbpf_bpf_map_create(attr);
if (ret < 0 && errno == EPERM) {
if (!allow_rlimit)
return ret;
// see note below about the rationale for this retry
struct rlimit rl = {};
if (getrlimit(RLIMIT_MEMLOCK, &rl) == 0) {
rl.rlim_max = RLIM_INFINITY;
rl.rlim_cur = rl.rlim_max;
if (setrlimit(RLIMIT_MEMLOCK, &rl) == 0)
ret = libbpf_bpf_map_create(attr);
}
}
// kernel already supports btf if its loading is successful,
// but this map type may not support pretty print yet.
if (ret < 0 && attr->btf_key_type_id && errno == 524 /* ENOTSUPP */) {
attr->btf_fd = 0;
attr->btf_key_type_id = 0;
attr->btf_value_type_id = 0;
ret = libbpf_bpf_map_create(attr);
}
if (ret < 0 && name_len && (errno == E2BIG || errno == EINVAL)) {
map_name[0] = '\0';
ret = libbpf_bpf_map_create(attr);
}
if (ret < 0 && errno == EPERM) {
if (!allow_rlimit)
return ret;
// see note below about the rationale for this retry
struct rlimit rl = {};
if (getrlimit(RLIMIT_MEMLOCK, &rl) == 0) {
rl.rlim_max = RLIM_INFINITY;
rl.rlim_cur = rl.rlim_max;
if (setrlimit(RLIMIT_MEMLOCK, &rl) == 0)
ret = libbpf_bpf_map_create(attr);
}
}
return ret;
}
int bcc_create_map(enum bpf_map_type map_type, const char *name,
int key_size, int value_size,
int max_entries, int map_flags)
{
struct bcc_create_map_attr attr = {};
attr.map_type = map_type;
attr.name = name;
attr.key_size = key_size;
attr.value_size = value_size;
attr.max_entries = max_entries;
attr.map_flags = map_flags;
return bcc_create_map_xattr(&attr, true);
}
int bpf_update_elem(int fd, void *key, void *value, unsigned long long flags)
{
return bpf_map_update_elem(fd, key, value, flags);
}
int bpf_lookup_elem(int fd, void *key, void *value)
{
return bpf_map_lookup_elem(fd, key, value);
}
int bpf_delete_elem(int fd, void *key)
{
return bpf_map_delete_elem(fd, key);
}
int bpf_lookup_and_delete(int fd, void *key, void *value)
{
return bpf_map_lookup_and_delete_elem(fd, key, value);
}
int bpf_lookup_batch(int fd, __u32 *in_batch, __u32 *out_batch, void *keys,
void *values, __u32 *count)
{
return bpf_map_lookup_batch(fd, in_batch, out_batch, keys, values, count,
NULL);
}
int bpf_delete_batch(int fd, void *keys, __u32 *count)
{
return bpf_map_delete_batch(fd, keys, count, NULL);
}
int bpf_update_batch(int fd, void *keys, void *values, __u32 *count)
{
return bpf_map_update_batch(fd, keys, values, count, NULL);
}
int bpf_lookup_and_delete_batch(int fd, __u32 *in_batch, __u32 *out_batch,
void *keys, void *values, __u32 *count)
{
return bpf_map_lookup_and_delete_batch(fd, in_batch, out_batch, keys, values,
count, NULL);
}
int bpf_get_first_key(int fd, void *key, size_t key_size)
{
int i, res;
// 4.12 and above kernel supports passing NULL to BPF_MAP_GET_NEXT_KEY
// to get first key of the map. For older kernels, the call will fail.
res = bpf_map_get_next_key(fd, 0, key);
if (res < 0 && errno == EFAULT) {
// Fall back to try to find a non-existing key.
static unsigned char try_values[3] = {0, 0xff, 0x55};
for (i = 0; i < 3; i++) {
memset(key, try_values[i], key_size);
// We want to check the existence of the key but we don't know the size
// of map's value. So we pass an invalid pointer for value, expect
// the call to fail and check if the error is ENOENT indicating the
// key doesn't exist. If we use NULL for the invalid pointer, it might
// trigger a page fault in kernel and affect performance. Hence we use
// ~0 which will fail and return fast.
// This should fail since we pass an invalid pointer for value.
if (bpf_map_lookup_elem(fd, key, (void *)~0) >= 0)
return -1;
// This means the key doesn't exist.
if (errno == ENOENT)
return bpf_map_get_next_key(fd, (void*)&try_values[i], key);
}
return -1;
} else {
return res;
}
}
int bpf_get_next_key(int fd, void *key, void *next_key)
{
return bpf_map_get_next_key(fd, key, next_key);
}
static void bpf_print_hints(int ret, char *log)
{
if (ret < 0)
fprintf(stderr, "bpf: Failed to load program: %s\n", strerror(errno));
if (log == NULL)
return;
else
fprintf(stderr, "%s\n", log);
if (ret >= 0)
return;
// The following error strings will need maintenance to match LLVM.
// stack busting
if (strstr(log, "invalid stack off=-") != NULL) {
fprintf(stderr, "HINT: Looks like you exceeded the BPF stack limit. "
"This can happen if you allocate too much local variable storage. "
"For example, if you allocated a 1 Kbyte struct (maybe for "
"BPF_PERF_OUTPUT), busting a max stack of 512 bytes.\n\n");
}
// didn't check NULL on map lookup
if (strstr(log, "invalid mem access 'map_value_or_null'") != NULL) {
fprintf(stderr, "HINT: The 'map_value_or_null' error can happen if "
"you dereference a pointer value from a map lookup without first "
"checking if that pointer is NULL.\n\n");
}
// lacking a bpf_probe_read
if (strstr(log, "invalid mem access 'inv'") != NULL) {
fprintf(stderr, "HINT: The invalid mem access 'inv' error can happen "
"if you try to dereference memory without first using "
"bpf_probe_read_kernel() to copy it to the BPF stack. Sometimes the "
"bpf_probe_read_kernel() is automatic by the bcc rewriter, other times "
"you'll need to be explicit.\n\n");
}
// referencing global/static variables or read only data
if (strstr(log, "unknown opcode") != NULL) {
fprintf(stderr, "HINT: The 'unknown opcode' can happen if you reference "
"a global or static variable, or data in read-only section. For example,"
" 'char *p = \"hello\"' will result in p referencing a read-only section,"
" and 'char p[] = \"hello\"' will have \"hello\" stored on the stack.\n\n");
}
// helper function not found in kernel
char *helper_str = strstr(log, "invalid func ");
if (helper_str != NULL) {
helper_str += strlen("invalid func ");
char *str = strchr(helper_str, '#');
if (str != NULL) {
helper_str = str + 1;
}
int helper_id = atoi(helper_str);
if (helper_id && helper_id < sizeof(helpers) / sizeof(struct bpf_helper)) {
struct bpf_helper helper = helpers[helper_id - 1];
fprintf(stderr, "HINT: bpf_%s missing (added in Linux %s).\n\n",
helper.name, helper.required_version);
}
}
}
#define ROUND_UP(x, n) (((x) + (n) - 1u) & ~((n) - 1u))
int bpf_obj_get_info(int prog_map_fd, void *info, uint32_t *info_len)
{
return bpf_obj_get_info_by_fd(prog_map_fd, info, info_len);
}
int bpf_prog_compute_tag(const struct bpf_insn *insns, int prog_len,
unsigned long long *ptag)
{
struct sockaddr_alg alg = {
.salg_family = AF_ALG,
.salg_type = "hash",
.salg_name = "sha1",
};
int shafd = socket(AF_ALG, SOCK_SEQPACKET, 0);
if (shafd < 0) {
fprintf(stderr, "sha1 socket not available %s\n", strerror(errno));
return -1;
}
int ret = bind(shafd, (struct sockaddr *)&alg, sizeof(alg));
if (ret < 0) {
fprintf(stderr, "sha1 bind fail %s\n", strerror(errno));
close(shafd);
return ret;
}
int shafd2 = accept(shafd, NULL, 0);
if (shafd2 < 0) {
fprintf(stderr, "sha1 accept fail %s\n", strerror(errno));
close(shafd);
return -1;
}
struct bpf_insn prog[prog_len / 8];
bool map_ld_seen = false;
int i;
for (i = 0; i < prog_len / 8; i++) {
prog[i] = insns[i];
if (insns[i].code == (BPF_LD | BPF_DW | BPF_IMM) &&
insns[i].src_reg == BPF_PSEUDO_MAP_FD &&
!map_ld_seen) {
prog[i].imm = 0;
map_ld_seen = true;
} else if (insns[i].code == 0 && map_ld_seen) {
prog[i].imm = 0;
map_ld_seen = false;
} else {
map_ld_seen = false;
}
}
ret = write(shafd2, prog, prog_len);
if (ret != prog_len) {
fprintf(stderr, "sha1 write fail %s\n", strerror(errno));
close(shafd2);
close(shafd);
return -1;
}
union {
unsigned char sha[20];
unsigned long long tag;
} u = {};
ret = read(shafd2, u.sha, 20);
if (ret != 20) {
fprintf(stderr, "sha1 read fail %s\n", strerror(errno));
close(shafd2);
close(shafd);
return -1;
}
*ptag = __builtin_bswap64(u.tag);
close(shafd2);
close(shafd);
return 0;
}
int bpf_prog_get_tag(int fd, unsigned long long *ptag)
{
char fmt[64];
snprintf(fmt, sizeof(fmt), "/proc/self/fdinfo/%d", fd);
FILE * f = fopen(fmt, "r");
if (!f) {
/* fprintf(stderr, "failed to open fdinfo %s\n", strerror(errno));*/
return -1;
}
unsigned long long tag = 0;
// prog_tag: can appear in different lines
while (fgets(fmt, sizeof(fmt), f)) {
if (sscanf(fmt, "prog_tag:%llx", &tag) == 1) {
*ptag = tag;
fclose(f);
return 0;
}
}
fclose(f);
return -2;
}
static int libbpf_bpf_prog_load(enum bpf_prog_type prog_type,
const char *prog_name, const char *license,
const struct bpf_insn *insns, size_t insn_cnt,
struct bpf_prog_load_opts *opts,
char *log_buf, size_t log_buf_sz)
{
LIBBPF_OPTS(bpf_prog_load_opts, p);
if (!opts || !log_buf != !log_buf_sz) {
errno = EINVAL;
return -EINVAL;
}
p.expected_attach_type = opts->expected_attach_type;
switch (prog_type) {
case BPF_PROG_TYPE_STRUCT_OPS:
case BPF_PROG_TYPE_LSM:
p.attach_btf_id = opts->attach_btf_id;
break;
case BPF_PROG_TYPE_TRACING:
case BPF_PROG_TYPE_EXT:
p.attach_btf_id = opts->attach_btf_id;
p.attach_prog_fd = opts->attach_prog_fd;
p.attach_btf_obj_fd = opts->attach_btf_obj_fd;
break;
default:
p.prog_ifindex = opts->prog_ifindex;
p.kern_version = opts->kern_version;
}
p.log_level = opts->log_level;
p.log_buf = log_buf;
p.log_size = log_buf_sz;
p.prog_btf_fd = opts->prog_btf_fd;
p.func_info_rec_size = opts->func_info_rec_size;
p.func_info_cnt = opts->func_info_cnt;
p.func_info = opts->func_info;
p.line_info_rec_size = opts->line_info_rec_size;
p.line_info_cnt = opts->line_info_cnt;
p.line_info = opts->line_info;
p.prog_flags = opts->prog_flags;
return bpf_prog_load(prog_type, prog_name, license,
insns, insn_cnt, &p);
}
static int find_btf_id(const char *module_name, const char *func_name,
enum bpf_attach_type expected_attach_type, int *btf_fd)
{
struct btf *vmlinux_btf = NULL, *module_btf = NULL;
struct bpf_btf_info info;
int err, fd, btf_id;
__u32 id = 0, len;
char name[64];
if (!module_name[0] || !strcmp(module_name, "vmlinux"))
return libbpf_find_vmlinux_btf_id(func_name, expected_attach_type);
while (true) {
err = bpf_btf_get_next_id(id, &id);
if (err) {
fprintf(stderr, "bpf_btf_get_next_id failed: %d\n", err);
return err;
}
fd = bpf_btf_get_fd_by_id(id);
if (fd < 0) {
err = fd;
fprintf(stderr, "bpf_btf_get_fd_by_id failed: %d\n", err);
return err;
}
len = sizeof(info);
memset(&info, 0, sizeof(info));
info.name = ptr_to_u64(name);
info.name_len = sizeof(name);
err = bpf_btf_get_info_by_fd(fd, &info, &len);
if (err) {
fprintf(stderr, "bpf_btf_get_info_by_fd failed: %d\n", err);
goto err_out;
}
if (!info.kernel_btf || strcmp(name, module_name)) {
close(fd);
continue;
}
vmlinux_btf = btf__load_vmlinux_btf();
err = libbpf_get_error(vmlinux_btf);
if (err) {
fprintf(stderr, "btf__load_vmlinux_btf failed: %d\n", err);
goto err_out;
}
module_btf = btf__load_module_btf(module_name, vmlinux_btf);
err = libbpf_get_error(vmlinux_btf);
if (err) {
fprintf(stderr, "btf__load_module_btf failed: %d\n", err);
goto err_out;
}
btf_id = btf__find_by_name_kind(module_btf, func_name, BTF_KIND_FUNC);
if (btf_id < 0) {
err = btf_id;
fprintf(stderr, "btf__find_by_name_kind failed: %d\n", err);
goto err_out;
}
btf__free(module_btf);
btf__free(vmlinux_btf);
*btf_fd = fd;
return btf_id;
err_out:
btf__free(module_btf);
btf__free(vmlinux_btf);
close(fd);
*btf_fd = -1;
return err;
}
return -1;
}
int bcc_prog_load_xattr(enum bpf_prog_type prog_type, const char *prog_name,
const char *license, const struct bpf_insn *insns,
struct bpf_prog_load_opts *opts, int prog_len,
char *log_buf, unsigned log_buf_size, bool allow_rlimit)
{
unsigned name_len = prog_name ? strlen(prog_name) : 0;
char *tmp_log_buf = NULL, *opts_log_buf = NULL;
unsigned tmp_log_buf_size = 0, opts_log_buf_size = 0;
int ret = 0, name_offset = 0, expected_attach_type = 0;
char new_prog_name[BPF_OBJ_NAME_LEN] = {};
char mod_name[64] = {};
char *mod_end;
int mod_len;
int fd = -1;
unsigned insns_cnt = prog_len / sizeof(struct bpf_insn);
if (opts->log_level > 0) {
if (log_buf_size > 0) {
// Use user-provided log buffer if available.
log_buf[0] = 0;
opts_log_buf = log_buf;
opts_log_buf_size = log_buf_size;
} else {
// Create and use temporary log buffer if user didn't provide one.
tmp_log_buf_size = LOG_BUF_SIZE;
tmp_log_buf = malloc(tmp_log_buf_size);
if (!tmp_log_buf) {
fprintf(stderr, "bpf: Failed to allocate temporary log buffer: %s\n\n",
strerror(errno));
opts->log_level = 0;
} else {
tmp_log_buf[0] = 0;
opts_log_buf = tmp_log_buf;
opts_log_buf_size = tmp_log_buf_size;
}
}
}
if (name_len) {
if (strncmp(prog_name, "kprobe__", 8) == 0)
name_offset = 8;
else if (strncmp(prog_name, "kretprobe__", 11) == 0)
name_offset = 11;
else if (strncmp(prog_name, "tracepoint__", 12) == 0)
name_offset = 12;
else if (strncmp(prog_name, "raw_tracepoint__", 16) == 0)
name_offset = 16;
else if (strncmp(prog_name, "kfunc__", 7) == 0) {
// kfunc__vmlinux__vfs_read
mod_end = strstr(prog_name + 7, "__");
mod_len = mod_end - prog_name - 7;
strncpy(mod_name, prog_name + 7, mod_len);
name_offset = 7 + mod_len + 2;
expected_attach_type = BPF_TRACE_FENTRY;
} else if (strncmp(prog_name, "kmod_ret__", 10) == 0) {
name_offset = 10;
expected_attach_type = BPF_MODIFY_RETURN;
} else if (strncmp(prog_name, "kretfunc__", 10) == 0) {
// kretfunc__vmlinux__vfs_read
mod_end = strstr(prog_name + 10, "__");
mod_len = mod_end - prog_name - 10;
strncpy(mod_name, prog_name + 10, mod_len);
name_offset = 10 + mod_len + 2;
expected_attach_type = BPF_TRACE_FEXIT;
} else if (strncmp(prog_name, "lsm__", 5) == 0) {
name_offset = 5;
expected_attach_type = BPF_LSM_MAC;
} else if (strncmp(prog_name, "bpf_iter__", 10) == 0) {
name_offset = 10;
expected_attach_type = BPF_TRACE_ITER;
}
if (prog_type == BPF_PROG_TYPE_TRACING ||
prog_type == BPF_PROG_TYPE_LSM) {
ret = find_btf_id(mod_name, prog_name + name_offset,
expected_attach_type, &fd);
if (ret == -EINVAL) {
fprintf(stderr, "bpf: %s BTF is not found\n", mod_name);
return ret;
} else if (ret < 0) {
fprintf(stderr, "bpf: %s is not found in %s BTF\n",
prog_name + name_offset, mod_name);
return ret;
}
opts->attach_btf_obj_fd = fd == -1 ? 0 : fd;
opts->attach_btf_id = ret;
opts->expected_attach_type = expected_attach_type;
}
memcpy(new_prog_name, prog_name + name_offset,
min(name_len - name_offset, BPF_OBJ_NAME_LEN - 1));
}
ret = libbpf_bpf_prog_load(prog_type, new_prog_name, license, insns, insns_cnt, opts, opts_log_buf, opts_log_buf_size);
// func_info/line_info may not be supported in old kernels.
if (ret < 0 && opts->func_info && errno == EINVAL) {
opts->prog_btf_fd = 0;
opts->func_info = NULL;
opts->func_info_cnt = 0;
opts->func_info_rec_size = 0;
opts->line_info = NULL;
opts->line_info_cnt = 0;
opts->line_info_rec_size = 0;
ret = libbpf_bpf_prog_load(prog_type, new_prog_name, license, insns, insns_cnt, opts, opts_log_buf, opts_log_buf_size);
}
// BPF object name is not supported on older Kernels.
// If we failed due to this, clear the name and try again.
if (ret < 0 && name_len && (errno == E2BIG || errno == EINVAL)) {
new_prog_name[0] = '\0';
ret = libbpf_bpf_prog_load(prog_type, new_prog_name, license, insns, insns_cnt, opts, opts_log_buf, opts_log_buf_size);
}
if (ret < 0 && errno == EPERM) {
if (!allow_rlimit)
return ret;
// When EPERM is returned, two reasons are possible:
// 1. user has no permissions for bpf()
// 2. user has insufficent rlimit for locked memory
// Unfortunately, there is no api to inspect the current usage of locked
// mem for the user, so an accurate calculation of how much memory to lock
// for this new program is difficult to calculate. As a hack, bump the limit
// to unlimited. If program load fails again, return the error.
struct rlimit rl = {};
if (getrlimit(RLIMIT_MEMLOCK, &rl) == 0) {
rl.rlim_max = RLIM_INFINITY;
rl.rlim_cur = rl.rlim_max;
if (setrlimit(RLIMIT_MEMLOCK, &rl) == 0)
ret = libbpf_bpf_prog_load(prog_type, new_prog_name, license, insns, insns_cnt, opts, opts_log_buf, opts_log_buf_size);
}
}
if (ret < 0 && errno == E2BIG) {
fprintf(stderr,
"bpf: %s. Program %s too large (%u insns), at most %d insns\n\n",
strerror(errno), new_prog_name, insns_cnt, BPF_MAXINSNS);
return -1;
}
// The load has failed. Handle log message.
if (ret < 0) {
// User has provided a log buffer.
if (log_buf_size) {
// If logging is not already enabled, enable it and do the syscall again.
if (opts->log_level == 0) {
opts->log_level = 1;
ret = libbpf_bpf_prog_load(prog_type, new_prog_name, license, insns, insns_cnt, opts, log_buf, log_buf_size);
}
// Print the log message and return.
bpf_print_hints(ret, log_buf);
if (errno == ENOSPC)
fprintf(stderr, "bpf: log_buf size may be insufficient\n");
goto return_result;
}
// User did not provide log buffer. We will try to increase size of
// our temporary log buffer to get full error message.
if (tmp_log_buf)
free(tmp_log_buf);
tmp_log_buf_size = LOG_BUF_SIZE;
if (opts->log_level == 0)
opts->log_level = 1;
for (;;) {
tmp_log_buf = malloc(tmp_log_buf_size);
if (!tmp_log_buf) {
fprintf(stderr, "bpf: Failed to allocate temporary log buffer: %s\n\n",
strerror(errno));
goto return_result;
}
tmp_log_buf[0] = 0;
ret = libbpf_bpf_prog_load(prog_type, new_prog_name, license, insns, insns_cnt, opts, tmp_log_buf, tmp_log_buf_size);
if (ret < 0 && errno == ENOSPC) {
// Temporary buffer size is not enough. Double it and try again.
free(tmp_log_buf);
tmp_log_buf = NULL;
tmp_log_buf_size <<= 1;
} else {
break;
}
}
}
// Check if we should print the log message if log_level is not 0,
// either specified by user or set due to error.
if (opts->log_level > 0) {
// Don't print if user enabled logging and provided log buffer,
// but there is no error.
if (log_buf && ret < 0)
bpf_print_hints(ret, log_buf);
else if (tmp_log_buf)
bpf_print_hints(ret, tmp_log_buf);
}
return_result:
if (fd >= 0)
close(fd);
if (tmp_log_buf)
free(tmp_log_buf);
return ret;
}
int bcc_prog_load(enum bpf_prog_type prog_type, const char *name,
const struct bpf_insn *insns, int prog_len,
const char *license, unsigned kern_version,
int log_level, char *log_buf, unsigned log_buf_size)
{
struct bpf_prog_load_opts opts = {};
if (prog_type != BPF_PROG_TYPE_TRACING && prog_type != BPF_PROG_TYPE_EXT)
opts.kern_version = kern_version;
opts.log_level = log_level;
return bcc_prog_load_xattr(prog_type, name, license, insns, &opts, prog_len, log_buf, log_buf_size, true);
}
int bpf_open_raw_sock(const char *name)
{
struct sockaddr_ll sll;