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https://git.kernel.org/pub/scm/network/iproute2/iproute2.git
synced 2024-11-30 13:26:12 +08:00
f8decf82af
If __NR_bpf is not enabled, bpf() function set errno and return -1. Thus,
this patch includes the header.
Fixes: ac4e0913be ("bpf: Export bpf syscall wrapper")
Signed-off-by: Juhee Kang <claudiajkang@gmail.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
92 lines
2.3 KiB
C
92 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* bpf_glue.c: BPF code to call both legacy and libbpf code
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* Authors: Hangbin Liu <haliu@redhat.com>
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*
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*/
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#include <sys/syscall.h>
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#include <limits.h>
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#include <unistd.h>
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#include <errno.h>
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#include "bpf_util.h"
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#ifdef HAVE_LIBBPF
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#include <bpf/bpf.h>
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#endif
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int bpf(int cmd, union bpf_attr *attr, unsigned int size)
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{
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#ifdef __NR_bpf
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return syscall(__NR_bpf, cmd, attr, size);
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#else
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fprintf(stderr, "No bpf syscall, kernel headers too old?\n");
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errno = ENOSYS;
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return -1;
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#endif
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}
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int bpf_program_attach(int prog_fd, int target_fd, enum bpf_attach_type type)
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{
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#ifdef HAVE_LIBBPF
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return bpf_prog_attach(prog_fd, target_fd, type, 0);
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#else
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return bpf_prog_attach_fd(prog_fd, target_fd, type);
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#endif
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}
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#ifdef HAVE_LIBBPF
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static const char *_libbpf_compile_version = LIBBPF_VERSION;
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static char _libbpf_version[10] = {};
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const char *get_libbpf_version(void)
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{
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/* Start by copying compile-time version into buffer so we have a
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* fallback value in case we are dynamically linked, or can't find a
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* version in /proc/self/maps below.
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*/
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strncpy(_libbpf_version, _libbpf_compile_version,
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sizeof(_libbpf_version)-1);
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#ifdef LIBBPF_DYNAMIC
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char buf[PATH_MAX], *s;
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bool found = false;
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FILE *fp;
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/* When dynamically linking against libbpf, we can't be sure that the
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* version we discovered at compile time is actually the one we are
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* using at runtime. This can lead to hard-to-debug errors, so we try to
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* discover the correct version at runtime.
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*
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* The simple solution to this would be if libbpf itself exported a
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* version in its API. But since it doesn't, we work around this by
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* parsing the mappings of the binary at runtime, looking for the full
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* filename of libbpf.so and using that.
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*/
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fp = fopen("/proc/self/maps", "r");
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if (fp == NULL)
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goto out;
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while (fgets(buf, sizeof(buf), fp) != NULL) {
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if ((s = strstr(buf, "libbpf.so.")) != NULL) {
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strncpy(_libbpf_version, s+10, sizeof(_libbpf_version)-1);
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strtok(_libbpf_version, "\n");
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found = true;
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break;
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}
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}
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fclose(fp);
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out:
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if (!found)
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fprintf(stderr, "Couldn't find runtime libbpf version - falling back to compile-time value!\n");
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#endif /* LIBBPF_DYNAMIC */
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_libbpf_version[sizeof(_libbpf_version)-1] = '\0';
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return _libbpf_version;
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}
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#else
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const char *get_libbpf_version(void)
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{
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return NULL;
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}
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#endif /* HAVE_LIBBPF */
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