lib/bpf/bpf.c

// SPDX-License-Identifier: LGPL-2.1

/*
 * common eBPF ELF operations.
 *
 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
 * Copyright (C) 2015 Huawei Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License (not later!)
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not,  see <http://www.gnu.org/licenses>
 */

#include <stdlib.h>
#include <memory.h>
#include <unistd.h>
#include <asm/unistd.h>
#include <linux/bpf.h>
#include "bpf.h"
#include "libbpf.h"
#include "nlattr.h"
#include <linux/rtnetlink.h>
#include <linux/if_link.h>
#include <sys/socket.h>
#include <errno.h>

#ifndef SOL_NETLINK
#define SOL_NETLINK 270
#endif

/*
 * When building perf, unistd.h is overridden. __NR_bpf is
 * required to be defined explicitly.
 */
#ifndef __NR_bpf
# if defined(__i386__)
#  define __NR_bpf 357
# elif defined(__x86_64__)
#  define __NR_bpf 321
# elif defined(__aarch64__)
#  define __NR_bpf 280
# elif defined(__sparc__)
#  define __NR_bpf 349
# elif defined(__s390__)
#  define __NR_bpf 351
# elif defined(__arc__)
#  define __NR_bpf 280
# else
#  error __NR_bpf not defined. libbpf does not support your arch.
# endif
#endif

#ifndef min
#define min(x, y) ((x) < (y) ? (x) : (y))
#endif

static inline __u64 ptr_to_u64(const void *ptr)
{
	return (__u64) (unsigned long) ptr;
}

static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
			  unsigned int size)
{
	return syscall(__NR_bpf, cmd, attr, size);
}

static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size)
{
	int fd;

	do {
		fd = sys_bpf(BPF_PROG_LOAD, attr, size);
	} while (fd < 0 && errno == EAGAIN);

	return fd;
}

int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)
{
	__u32 name_len = create_attr->name ? strlen(create_attr->name) : 0;
	union bpf_attr attr;
	int ret;

	memset(&attr, '\0', sizeof(attr));

	attr.map_type = create_attr->map_type;
	attr.key_size = create_attr->key_size;
	attr.value_size = create_attr->value_size;
	attr.max_entries = create_attr->max_entries;
	attr.map_flags = create_attr->map_flags;
	memcpy(attr.map_name, create_attr->name,
	       min(name_len, BPF_OBJ_NAME_LEN - 1));
	attr.numa_node = create_attr->numa_node;
	attr.btf_fd = create_attr->btf_fd;
	attr.btf_key_type_id = create_attr->btf_key_type_id;
	attr.btf_value_type_id = create_attr->btf_value_type_id;
	attr.map_ifindex = create_attr->map_ifindex;
	attr.inner_map_fd = create_attr->inner_map_fd;

	ret = sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
	if (ret < 0 && errno == EINVAL && create_attr->name) {
		/* Retry the same syscall, but without the name.
		 * Pre v4.14 kernels don't support map names.
		 */
		memset(attr.map_name, 0, sizeof(attr.map_name));
		return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
	}
	return ret;
}

int bpf_create_map_node(enum bpf_map_type map_type, const char *name,
			int key_size, int value_size, int max_entries,
			__u32 map_flags, int node)
{
	struct bpf_create_map_attr map_attr = {};

	map_attr.name = name;
	map_attr.map_type = map_type;
	map_attr.map_flags = map_flags;
	map_attr.key_size = key_size;
	map_attr.value_size = value_size;
	map_attr.max_entries = max_entries;
	if (node >= 0) {
		map_attr.numa_node = node;
		map_attr.map_flags |= BPF_F_NUMA_NODE;
	}

	return bpf_create_map_xattr(&map_attr);
}

int bpf_create_map(enum bpf_map_type map_type, int key_size,
		   int value_size, int max_entries, __u32 map_flags)
{
	struct bpf_create_map_attr map_attr = {};

	map_attr.map_type = map_type;
	map_attr.map_flags = map_flags;
	map_attr.key_size = key_size;
	map_attr.value_size = value_size;
	map_attr.max_entries = max_entries;

	return bpf_create_map_xattr(&map_attr);
}

int bpf_create_map_name(enum bpf_map_type map_type, const char *name,
			int key_size, int value_size, int max_entries,
			__u32 map_flags)
{
	struct bpf_create_map_attr map_attr = {};

	map_attr.name = name;
	map_attr.map_type = map_type;
	map_attr.map_flags = map_flags;
	map_attr.key_size = key_size;
	map_attr.value_size = value_size;
	map_attr.max_entries = max_entries;

	return bpf_create_map_xattr(&map_attr);
}

int bpf_create_map_in_map_node(enum bpf_map_type map_type, const char *name,
			       int key_size, int inner_map_fd, int max_entries,
			       __u32 map_flags, int node)
{
	__u32 name_len = name ? strlen(name) : 0;
	union bpf_attr attr;

	memset(&attr, '\0', sizeof(attr));

	attr.map_type = map_type;
	attr.key_size = key_size;
	attr.value_size = 4;
	attr.inner_map_fd = inner_map_fd;
	attr.max_entries = max_entries;
	attr.map_flags = map_flags;
	memcpy(attr.map_name, name, min(name_len, BPF_OBJ_NAME_LEN - 1));

	if (node >= 0) {
		attr.map_flags |= BPF_F_NUMA_NODE;
		attr.numa_node = node;
	}

	return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
}

int bpf_create_map_in_map(enum bpf_map_type map_type, const char *name,
			  int key_size, int inner_map_fd, int max_entries,
			  __u32 map_flags)
{
	return bpf_create_map_in_map_node(map_type, name, key_size,
					  inner_map_fd, max_entries, map_flags,
					  -1);
}

int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
			   char *log_buf, size_t log_buf_sz)
{
	union bpf_attr attr;
	__u32 name_len;
	int fd;

	if (!load_attr)
		return -EINVAL;

	name_len = load_attr->name ? strlen(load_attr->name) : 0;

	bzero(&attr, sizeof(attr));
	attr.prog_type = load_attr->prog_type;
	attr.expected_attach_type = load_attr->expected_attach_type;
	attr.insn_cnt = (__u32)load_attr->insns_cnt;
	attr.insns = ptr_to_u64(load_attr->insns);
	attr.license = ptr_to_u64(load_attr->license);
	attr.log_buf = ptr_to_u64(NULL);
	attr.log_size = 0;
	attr.log_level = 0;
	attr.kern_version = load_attr->kern_version;
	attr.prog_ifindex = load_attr->prog_ifindex;
	memcpy(attr.prog_name, load_attr->name,
	       min(name_len, BPF_OBJ_NAME_LEN - 1));

	fd = sys_bpf_prog_load(&attr, sizeof(attr));
	if (fd >= 0 || !log_buf || !log_buf_sz)
		return fd;

	/* Try again with log */
	attr.log_buf = ptr_to_u64(log_buf);
	attr.log_size = log_buf_sz;
	attr.log_level = 1;
	log_buf[0] = 0;
	return sys_bpf_prog_load(&attr, sizeof(attr));
}

int bpf_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
		     size_t insns_cnt, const char *license,
		     __u32 kern_version, char *log_buf,
		     size_t log_buf_sz)
{
	struct bpf_load_program_attr load_attr;

	memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
	load_attr.prog_type = type;
	load_attr.expected_attach_type = 0;
	load_attr.name = NULL;
	load_attr.insns = insns;
	load_attr.insns_cnt = insns_cnt;
	load_attr.license = license;
	load_attr.kern_version = kern_version;

	return bpf_load_program_xattr(&load_attr, log_buf, log_buf_sz);
}

int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
		       size_t insns_cnt, int strict_alignment,
		       const char *license, __u32 kern_version,
		       char *log_buf, size_t log_buf_sz, int log_level)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.prog_type = type;
	attr.insn_cnt = (__u32)insns_cnt;
	attr.insns = ptr_to_u64(insns);
	attr.license = ptr_to_u64(license);
	attr.log_buf = ptr_to_u64(log_buf);
	attr.log_size = log_buf_sz;
	attr.log_level = log_level;
	log_buf[0] = 0;
	attr.kern_version = kern_version;
	attr.prog_flags = strict_alignment ? BPF_F_STRICT_ALIGNMENT : 0;

	return sys_bpf_prog_load(&attr, sizeof(attr));
}

int bpf_map_update_elem(int fd, const void *key, const void *value,
			__u64 flags)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.map_fd = fd;
	attr.key = ptr_to_u64(key);
	attr.value = ptr_to_u64(value);
	attr.flags = flags;

	return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
}

int bpf_map_lookup_elem(int fd, const void *key, void *value)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.map_fd = fd;
	attr.key = ptr_to_u64(key);
	attr.value = ptr_to_u64(value);

	return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
}

int bpf_map_delete_elem(int fd, const void *key)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.map_fd = fd;
	attr.key = ptr_to_u64(key);

	return sys_bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr));
}

int bpf_map_get_next_key(int fd, const void *key, void *next_key)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.map_fd = fd;
	attr.key = ptr_to_u64(key);
	attr.next_key = ptr_to_u64(next_key);

	return sys_bpf(BPF_MAP_GET_NEXT_KEY, &attr, sizeof(attr));
}

int bpf_obj_pin(int fd, const char *pathname)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.pathname = ptr_to_u64((void *)pathname);
	attr.bpf_fd = fd;

	return sys_bpf(BPF_OBJ_PIN, &attr, sizeof(attr));
}

int bpf_obj_get(const char *pathname)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.pathname = ptr_to_u64((void *)pathname);

	return sys_bpf(BPF_OBJ_GET, &attr, sizeof(attr));
}

int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
		    unsigned int flags)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.target_fd	   = target_fd;
	attr.attach_bpf_fd = prog_fd;
	attr.attach_type   = type;
	attr.attach_flags  = flags;

	return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
}

int bpf_prog_detach(int target_fd, enum bpf_attach_type type)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.target_fd	 = target_fd;
	attr.attach_type = type;

	return sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr));
}

int bpf_prog_detach2(int prog_fd, int target_fd, enum bpf_attach_type type)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.target_fd	 = target_fd;
	attr.attach_bpf_fd = prog_fd;
	attr.attach_type = type;

	return sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr));
}

int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags,
		   __u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt)
{
	union bpf_attr attr;
	int ret;

	bzero(&attr, sizeof(attr));
	attr.query.target_fd	= target_fd;
	attr.query.attach_type	= type;
	attr.query.query_flags	= query_flags;
	attr.query.prog_cnt	= *prog_cnt;
	attr.query.prog_ids	= ptr_to_u64(prog_ids);

	ret = sys_bpf(BPF_PROG_QUERY, &attr, sizeof(attr));
	if (attach_flags)
		*attach_flags = attr.query.attach_flags;
	*prog_cnt = attr.query.prog_cnt;
	return ret;
}

int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
		      void *data_out, __u32 *size_out, __u32 *retval,
		      __u32 *duration)
{
	union bpf_attr attr;
	int ret;

	bzero(&attr, sizeof(attr));
	attr.test.prog_fd = prog_fd;
	attr.test.data_in = ptr_to_u64(data);
	attr.test.data_out = ptr_to_u64(data_out);
	attr.test.data_size_in = size;
	attr.test.repeat = repeat;

	ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr));
	if (size_out)
		*size_out = attr.test.data_size_out;
	if (retval)
		*retval = attr.test.retval;
	if (duration)
		*duration = attr.test.duration;
	return ret;
}

int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id)
{
	union bpf_attr attr;
	int err;

	bzero(&attr, sizeof(attr));
	attr.start_id = start_id;

	err = sys_bpf(BPF_PROG_GET_NEXT_ID, &attr, sizeof(attr));
	if (!err)
		*next_id = attr.next_id;

	return err;
}

int bpf_map_get_next_id(__u32 start_id, __u32 *next_id)
{
	union bpf_attr attr;
	int err;

	bzero(&attr, sizeof(attr));
	attr.start_id = start_id;

	err = sys_bpf(BPF_MAP_GET_NEXT_ID, &attr, sizeof(attr));
	if (!err)
		*next_id = attr.next_id;

	return err;
}

int bpf_prog_get_fd_by_id(__u32 id)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.prog_id = id;

	return sys_bpf(BPF_PROG_GET_FD_BY_ID, &attr, sizeof(attr));
}

int bpf_map_get_fd_by_id(__u32 id)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.map_id = id;

	return sys_bpf(BPF_MAP_GET_FD_BY_ID, &attr, sizeof(attr));
}

int bpf_btf_get_fd_by_id(__u32 id)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.btf_id = id;

	return sys_bpf(BPF_BTF_GET_FD_BY_ID, &attr, sizeof(attr));
}

int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len)
{
	union bpf_attr attr;
	int err;

	bzero(&attr, sizeof(attr));
	attr.info.bpf_fd = prog_fd;
	attr.info.info_len = *info_len;
	attr.info.info = ptr_to_u64(info);

	err = sys_bpf(BPF_OBJ_GET_INFO_BY_FD, &attr, sizeof(attr));
	if (!err)
		*info_len = attr.info.info_len;

	return err;
}

int bpf_raw_tracepoint_open(const char *name, int prog_fd)
{
	union bpf_attr attr;

	bzero(&attr, sizeof(attr));
	attr.raw_tracepoint.name = ptr_to_u64(name);
	attr.raw_tracepoint.prog_fd = prog_fd;

	return sys_bpf(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr));
}

int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
{
	struct sockaddr_nl sa;
	int sock, seq = 0, len, ret = -1;
	char buf[4096];
	struct nlattr *nla, *nla_xdp;
	struct {
		struct nlmsghdr  nh;
		struct ifinfomsg ifinfo;
		char             attrbuf[64];
	} req;
	struct nlmsghdr *nh;
	struct nlmsgerr *err;
	socklen_t addrlen;
	int one = 1;

	memset(&sa, 0, sizeof(sa));
	sa.nl_family = AF_NETLINK;

	sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
	if (sock < 0) {
		return -errno;
	}

	if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK,
		       &one, sizeof(one)) < 0) {
		fprintf(stderr, "Netlink error reporting not supported\n");
	}

	if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
		ret = -errno;
		goto cleanup;
	}

	addrlen = sizeof(sa);
	if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
		ret = -errno;
		goto cleanup;
	}

	if (addrlen != sizeof(sa)) {
		ret = -LIBBPF_ERRNO__INTERNAL;
		goto cleanup;
	}

	memset(&req, 0, sizeof(req));
	req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
	req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
	req.nh.nlmsg_type = RTM_SETLINK;
	req.nh.nlmsg_pid = 0;
	req.nh.nlmsg_seq = ++seq;
	req.ifinfo.ifi_family = AF_UNSPEC;
	req.ifinfo.ifi_index = ifindex;

	/* started nested attribute for XDP */
	nla = (struct nlattr *)(((char *)&req)
				+ NLMSG_ALIGN(req.nh.nlmsg_len));
	nla->nla_type = NLA_F_NESTED | IFLA_XDP;
	nla->nla_len = NLA_HDRLEN;

	/* add XDP fd */
	nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
	nla_xdp->nla_type = IFLA_XDP_FD;
	nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
	memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd));
	nla->nla_len += nla_xdp->nla_len;

	/* if user passed in any flags, add those too */
	if (flags) {
		nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
		nla_xdp->nla_type = IFLA_XDP_FLAGS;
		nla_xdp->nla_len = NLA_HDRLEN + sizeof(flags);
		memcpy((char *)nla_xdp + NLA_HDRLEN, &flags, sizeof(flags));
		nla->nla_len += nla_xdp->nla_len;
	}

	req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);

	if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
		ret = -errno;
		goto cleanup;
	}

	len = recv(sock, buf, sizeof(buf), 0);
	if (len < 0) {
		ret = -errno;
		goto cleanup;
	}

	for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
	     nh = NLMSG_NEXT(nh, len)) {
		if (nh->nlmsg_pid != sa.nl_pid) {
			ret = -LIBBPF_ERRNO__WRNGPID;
			goto cleanup;
		}
		if (nh->nlmsg_seq != seq) {
			ret = -LIBBPF_ERRNO__INVSEQ;
			goto cleanup;
		}
		switch (nh->nlmsg_type) {
		case NLMSG_ERROR:
			err = (struct nlmsgerr *)NLMSG_DATA(nh);
			if (!err->error)
				continue;
			ret = err->error;
			nla_dump_errormsg(nh);
			goto cleanup;
		case NLMSG_DONE:
			break;
		default:
			break;
		}
	}

	ret = 0;

cleanup:
	close(sock);
	return ret;
}

int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size,
		 bool do_log)
{
	union bpf_attr attr = {};
	int fd;

	attr.btf = ptr_to_u64(btf);
	attr.btf_size = btf_size;

retry:
	if (do_log && log_buf && log_buf_size) {
		attr.btf_log_level = 1;
		attr.btf_log_size = log_buf_size;
		attr.btf_log_buf = ptr_to_u64(log_buf);
	}

	fd = sys_bpf(BPF_BTF_LOAD, &attr, sizeof(attr));
	if (fd == -1 && !do_log && log_buf && log_buf_size) {
		do_log = true;
		goto retry;
	}

	return fd;
}

int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len,
		      __u32 *prog_id, __u32 *fd_type, __u64 *probe_offset,
		      __u64 *probe_addr)
{
	union bpf_attr attr = {};
	int err;

	attr.task_fd_query.pid = pid;
	attr.task_fd_query.fd = fd;
	attr.task_fd_query.flags = flags;
	attr.task_fd_query.buf = ptr_to_u64(buf);
	attr.task_fd_query.buf_len = *buf_len;

	err = sys_bpf(BPF_TASK_FD_QUERY, &attr, sizeof(attr));
	*buf_len = attr.task_fd_query.buf_len;
	*prog_id = attr.task_fd_query.prog_id;
	*fd_type = attr.task_fd_query.fd_type;
	*probe_offset = attr.task_fd_query.probe_offset;
	*probe_addr = attr.task_fd_query.probe_addr;

	return err;
}