diff --git a/configure b/configure index 307912aa..2c363d3b 100755 --- a/configure +++ b/configure @@ -2,6 +2,11 @@ # SPDX-License-Identifier: GPL-2.0 # This is not an autoconf generated configure # +# Influential LIBBPF environment variables: +# LIBBPF_FORCE={on,off} on: require link against libbpf; +# off: disable libbpf probing +# LIBBPF_DIR Path to libbpf DESTDIR to use + INCLUDE=${1:-"$PWD/include"} # Output file which is input to Makefile @@ -240,6 +245,111 @@ check_elf() fi } +have_libbpf_basic() +{ + cat >$TMPDIR/libbpf_test.c < +int main(int argc, char **argv) { + bpf_program__set_autoload(NULL, false); + bpf_map__ifindex(NULL); + bpf_map__set_pin_path(NULL, NULL); + bpf_object__open_file(NULL, NULL); + return 0; +} +EOF + + $CC -o $TMPDIR/libbpf_test $TMPDIR/libbpf_test.c $LIBBPF_CFLAGS $LIBBPF_LDLIBS >/dev/null 2>&1 + local ret=$? + + rm -f $TMPDIR/libbpf_test.c $TMPDIR/libbpf_test + return $ret +} + +have_libbpf_sec_name() +{ + cat >$TMPDIR/libbpf_sec_test.c < +int main(int argc, char **argv) { + void *ptr; + bpf_program__section_name(NULL); + return 0; +} +EOF + + $CC -o $TMPDIR/libbpf_sec_test $TMPDIR/libbpf_sec_test.c $LIBBPF_CFLAGS $LIBBPF_LDLIBS >/dev/null 2>&1 + local ret=$? + + rm -f $TMPDIR/libbpf_sec_test.c $TMPDIR/libbpf_sec_test + return $ret +} + +check_force_libbpf_on() +{ + # if set LIBBPF_FORCE=on but no libbpf support, just exist the config + # process to make sure we don't build without libbpf. + if [ "$LIBBPF_FORCE" = on ]; then + echo " LIBBPF_FORCE=on set, but couldn't find a usable libbpf" + exit 1 + fi +} + +check_libbpf() +{ + # if set LIBBPF_FORCE=off, disable libbpf entirely + if [ "$LIBBPF_FORCE" = off ]; then + echo "no" + return + fi + + if ! ${PKG_CONFIG} libbpf --exists && [ -z "$LIBBPF_DIR" ] ; then + echo "no" + check_force_libbpf_on + return + fi + + if [ $(uname -m) = x86_64 ]; then + local LIBBPF_LIBDIR="${LIBBPF_DIR}/usr/lib64" + else + local LIBBPF_LIBDIR="${LIBBPF_DIR}/usr/lib" + fi + + if [ -n "$LIBBPF_DIR" ]; then + LIBBPF_CFLAGS="-I${LIBBPF_DIR}/usr/include" + LIBBPF_LDLIBS="${LIBBPF_LIBDIR}/libbpf.a -lz -lelf" + LIBBPF_VERSION=$(PKG_CONFIG_LIBDIR=${LIBBPF_LIBDIR}/pkgconfig ${PKG_CONFIG} libbpf --modversion) + else + LIBBPF_CFLAGS=$(${PKG_CONFIG} libbpf --cflags) + LIBBPF_LDLIBS=$(${PKG_CONFIG} libbpf --libs) + LIBBPF_VERSION=$(${PKG_CONFIG} libbpf --modversion) + fi + + if ! have_libbpf_basic; then + echo "no" + echo " libbpf version $LIBBPF_VERSION is too low, please update it to at least 0.1.0" + check_force_libbpf_on + return + else + echo "HAVE_LIBBPF:=y" >> $CONFIG + echo 'CFLAGS += -DHAVE_LIBBPF ' $LIBBPF_CFLAGS >> $CONFIG + echo "CFLAGS += -DLIBBPF_VERSION=\\\"$LIBBPF_VERSION\\\"" >> $CONFIG + echo 'LDLIBS += ' $LIBBPF_LDLIBS >> $CONFIG + + if [ -z "$LIBBPF_DIR" ]; then + echo "CFLAGS += -DLIBBPF_DYNAMIC" >> $CONFIG + fi + fi + + # bpf_program__title() is deprecated since libbpf 0.2.0, use + # bpf_program__section_name() instead if we support + if have_libbpf_sec_name; then + echo "HAVE_LIBBPF_SECTION_NAME:=y" >> $CONFIG + echo 'CFLAGS += -DHAVE_LIBBPF_SECTION_NAME ' >> $CONFIG + fi + + echo "yes" + echo " libbpf version $LIBBPF_VERSION" +} + check_selinux() # SELinux is a compile time option in the ss utility { @@ -385,6 +495,9 @@ check_setns echo -n "SELinux support: " check_selinux +echo -n "libbpf support: " +check_libbpf + echo -n "ELF support: " check_elf diff --git a/include/bpf_util.h b/include/bpf_util.h index 63db07ca..dee5bb02 100644 --- a/include/bpf_util.h +++ b/include/bpf_util.h @@ -300,4 +300,7 @@ static inline int bpf_recv_map_fds(const char *path, int *fds, return -1; } #endif /* HAVE_ELF */ + +const char *get_libbpf_version(void); + #endif /* __BPF_UTIL__ */ diff --git a/ip/ip.c b/ip/ip.c index 5e31957f..466dbb52 100644 --- a/ip/ip.c +++ b/ip/ip.c @@ -24,6 +24,7 @@ #include "namespace.h" #include "color.h" #include "rt_names.h" +#include "bpf_util.h" int preferred_family = AF_UNSPEC; int human_readable; @@ -147,8 +148,9 @@ static int batch(const char *name) int main(int argc, char **argv) { - char *basename; + const char *libbpf_version; char *batch_file = NULL; + char *basename; int color = 0; /* to run vrf exec without root, capabilities might be set, drop them @@ -229,7 +231,11 @@ int main(int argc, char **argv) ++timestamp; ++timestamp_short; } else if (matches(opt, "-Version") == 0) { - printf("ip utility, iproute2-%s\n", version); + printf("ip utility, iproute2-%s", version); + libbpf_version = get_libbpf_version(); + if (libbpf_version) + printf(", libbpf %s", libbpf_version); + printf("\n"); exit(0); } else if (matches(opt, "-force") == 0) { ++force; diff --git a/lib/Makefile b/lib/Makefile index 13f4ee15..a02775a5 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -5,7 +5,7 @@ CFLAGS += -fPIC UTILOBJ = utils.o rt_names.o ll_map.o ll_types.o ll_proto.o ll_addr.o \ inet_proto.o namespace.o json_writer.o json_print.o \ - names.o color.o bpf.o exec.o fs.o cg_map.o + names.o color.o bpf.o bpf_glue.o exec.o fs.o cg_map.o NLOBJ=libgenl.o libnetlink.o mnl_utils.o diff --git a/lib/bpf_glue.c b/lib/bpf_glue.c new file mode 100644 index 00000000..67c41c22 --- /dev/null +++ b/lib/bpf_glue.c @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * bpf_glue.c: BPF code to call both legacy and libbpf code + * Authors: Hangbin Liu + * + */ +#include "bpf_util.h" + +#ifdef HAVE_LIBBPF +static const char *_libbpf_compile_version = LIBBPF_VERSION; +static char _libbpf_version[10] = {}; + +const char *get_libbpf_version(void) +{ + /* Start by copying compile-time version into buffer so we have a + * fallback value in case we are dynamically linked, or can't find a + * version in /proc/self/maps below. + */ + strncpy(_libbpf_version, _libbpf_compile_version, + sizeof(_libbpf_version)-1); +#ifdef LIBBPF_DYNAMIC + char buf[PATH_MAX], *s; + bool found = false; + FILE *fp; + + /* When dynamically linking against libbpf, we can't be sure that the + * version we discovered at compile time is actually the one we are + * using at runtime. This can lead to hard-to-debug errors, so we try to + * discover the correct version at runtime. + * + * The simple solution to this would be if libbpf itself exported a + * version in its API. But since it doesn't, we work around this by + * parsing the mappings of the binary at runtime, looking for the full + * filename of libbpf.so and using that. + */ + fp = fopen("/proc/self/maps", "r"); + if (fp == NULL) + goto out; + + while ((s = fgets(buf, sizeof(buf), fp)) != NULL) { + if ((s = strstr(buf, "libbpf.so.")) != NULL) { + strncpy(_libbpf_version, s+10, sizeof(_libbpf_version)-1); + strtok(_libbpf_version, "\n"); + found = true; + break; + } + } + + fclose(fp); +out: + if (!found) + fprintf(stderr, "Couldn't find runtime libbpf version - falling back to compile-time value!\n"); +#endif /* LIBBPF_DYNAMIC */ + + _libbpf_version[sizeof(_libbpf_version)-1] = '\0'; + return _libbpf_version; +} +#else +const char *get_libbpf_version(void) +{ + return NULL; +} +#endif /* HAVE_LIBBPF */ diff --git a/tc/tc.c b/tc/tc.c index af9b21da..7557b977 100644 --- a/tc/tc.c +++ b/tc/tc.c @@ -30,6 +30,7 @@ #include "tc_common.h" #include "namespace.h" #include "rt_names.h" +#include "bpf_util.h" int show_stats; int show_details; @@ -259,8 +260,9 @@ static int batch(const char *name) int main(int argc, char **argv) { - int ret; + const char *libbpf_version; char *batch_file = NULL; + int ret; while (argc > 1) { if (argv[1][0] != '-') @@ -277,7 +279,11 @@ int main(int argc, char **argv) } else if (matches(argv[1], "-graph") == 0) { show_graph = 1; } else if (matches(argv[1], "-Version") == 0) { - printf("tc utility, iproute2-%s\n", version); + printf("tc utility, iproute2-%s", version); + libbpf_version = get_libbpf_version(); + if (libbpf_version) + printf(", libbpf %s", libbpf_version); + printf("\n"); return 0; } else if (matches(argv[1], "-iec") == 0) { ++use_iec;