ucode-mod-bpf: add new package for a ucode libbpf binding

The bpf plugin provides functionality for loading and interacting with
eBPF modules.

It allows loading full modules and pinned maps/programs and supports
interacting with maps and attaching programs as tc classifiers.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
Felix Fietkau 2023-01-08 20:40:40 +01:00
parent d6a284e4ce
commit 0cc1c302b1
2 changed files with 854 additions and 0 deletions

View File

@ -0,0 +1,40 @@
include $(TOPDIR)/rules.mk
PKG_NAME:=ucode-mod-bpf
PKG_RELEASE:=1
PKG_LICENSE:=ISC
PKG_MAINTAINER:=Felix Fietkau <nbd@nbd.name>
include $(INCLUDE_DIR)/package.mk
include $(INCLUDE_DIR)/nls.mk
define Package/ucode-mod-bpf
SECTION:=utils
CATEGORY:=Utilities
TITLE:=ucode eBPF module
DEPENDS:=+libucode +libbpf
endef
define Package/ucode-mod-bpf/description
The bpf plugin provides functionality for loading and interacting with
eBPF modules.
It allows loading full modules and pinned maps/programs and supports
interacting with maps and attaching programs as tc classifiers.
endef
define Package/ucode-mod-bpf/install
$(INSTALL_DIR) $(1)/usr/lib/ucode
$(CP) $(PKG_BUILD_DIR)/bpf.so $(1)/usr/lib/ucode/
endef
define Build/Configure
endef
define Build/Compile
$(TARGET_CC) $(TARGET_CFLAGS) $(TARGET_LDFLAGS) $(FPIC) \
-Wall -ffunction-sections -Wl,--gc-sections -shared -Wl,--no-as-needed -lbpf \
-o $(PKG_BUILD_DIR)/bpf.so $(PKG_BUILD_DIR)/bpf.c
endef
$(eval $(call BuildPackage,ucode-mod-bpf))

View File

@ -0,0 +1,814 @@
#include <sys/resource.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <stdint.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "ucode/module.h"
#define err_return_int(err, ...) do { set_error(err, __VA_ARGS__); return -1; } while(0)
#define err_return(err, ...) do { set_error(err, __VA_ARGS__); return NULL; } while(0)
#define TRUE ucv_boolean_new(true)
static uc_resource_type_t *module_type, *map_type, *map_iter_type, *program_type;
static uc_value_t *registry;
static uc_vm_t *debug_vm;
static struct {
int code;
char *msg;
} last_error;
struct uc_bpf_fd {
int fd;
bool close;
};
struct uc_bpf_map {
struct uc_bpf_fd fd; /* must be first */
unsigned int key_size, val_size;
};
struct uc_bpf_map_iter {
int fd;
unsigned int key_size;
bool has_next;
uint8_t key[];
};
__attribute__((format(printf, 2, 3))) static void
set_error(int errcode, const char *fmt, ...)
{
va_list ap;
free(last_error.msg);
last_error.code = errcode;
last_error.msg = NULL;
if (fmt) {
va_start(ap, fmt);
xvasprintf(&last_error.msg, fmt, ap);
va_end(ap);
}
}
static void init_env(void)
{
static bool init_done = false;
struct rlimit limit = {
.rlim_cur = RLIM_INFINITY,
.rlim_max = RLIM_INFINITY,
};
if (init_done)
return;
setrlimit(RLIMIT_MEMLOCK, &limit);
init_done = true;
}
static uc_value_t *
uc_bpf_error(uc_vm_t *vm, size_t nargs)
{
uc_value_t *numeric = uc_fn_arg(0);
const char *msg = last_error.msg;
int code = last_error.code;
uc_stringbuf_t *buf;
const char *s;
if (last_error.code == 0)
return NULL;
set_error(0, NULL);
if (ucv_is_truish(numeric))
return ucv_int64_new(code);
buf = ucv_stringbuf_new();
if (code < 0 && msg) {
ucv_stringbuf_addstr(buf, msg, strlen(msg));
} else {
s = strerror(code);
ucv_stringbuf_addstr(buf, s, strlen(s));
if (msg)
ucv_stringbuf_printf(buf, ": %s", msg);
}
return ucv_stringbuf_finish(buf);
}
static int
uc_bpf_module_set_opts(struct bpf_object *obj, uc_value_t *opts)
{
uc_value_t *val;
if (!opts)
return 0;
if (ucv_type(opts) != UC_OBJECT)
err_return_int(EINVAL, "options argument");
if ((val = ucv_object_get(opts, "rodata", NULL)) != NULL) {
struct bpf_map *map = NULL;
if (ucv_type(val) != UC_STRING)
err_return_int(EINVAL, "rodata type");
while ((map = bpf_object__next_map(obj, map)) != NULL) {
if (!strstr(bpf_map__name(map), ".rodata"))
continue;
break;
}
if (!map)
err_return_int(errno, "rodata map");
if (bpf_map__set_initial_value(map, ucv_string_get(val),
ucv_string_length(val)))
err_return_int(errno, "rodata");
}
if ((val = ucv_object_get(opts, "program-type", NULL)) != NULL) {
if (ucv_type(val) != UC_OBJECT)
err_return_int(EINVAL, "prog_types argument");
ucv_object_foreach(val, name, type) {
struct bpf_program *prog;
if (ucv_type(type) != UC_INTEGER)
err_return_int(EINVAL, "program %s type", name);
prog = bpf_object__find_program_by_name(obj, name);
if (!prog)
err_return_int(-1, "program %s not found", name);
bpf_program__set_type(prog, ucv_int64_get(type));
}
}
return 0;
}
static uc_value_t *
uc_bpf_open_module(uc_vm_t *vm, size_t nargs)
{
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, bpf_opts);
uc_value_t *path = uc_fn_arg(0);
uc_value_t *opts = uc_fn_arg(1);
struct bpf_object *obj;
if (ucv_type(path) != UC_STRING)
err_return(EINVAL, "module path");
init_env();
obj = bpf_object__open_file(ucv_string_get(path), &bpf_opts);
if (libbpf_get_error(obj))
err_return(errno, NULL);
if (uc_bpf_module_set_opts(obj, opts)) {
bpf_object__close(obj);
return NULL;
}
if (bpf_object__load(obj)) {
bpf_object__close(obj);
err_return(errno, NULL);
}
return uc_resource_new(module_type, obj);
}
static uc_value_t *
uc_bpf_map_create(int fd, unsigned int key_size, unsigned int val_size, bool close)
{
struct uc_bpf_map *uc_map;
uc_map = xalloc(sizeof(*uc_map));
uc_map->fd.fd = fd;
uc_map->key_size = key_size;
uc_map->val_size = val_size;
uc_map->fd.close = close;
return uc_resource_new(map_type, uc_map);
}
static uc_value_t *
uc_bpf_open_map(uc_vm_t *vm, size_t nargs)
{
struct bpf_map_info info;
uc_value_t *path = uc_fn_arg(0);
__u32 len = sizeof(info);
int err;
int fd;
if (ucv_type(path) != UC_STRING)
err_return(EINVAL, "module path");
fd = bpf_obj_get(ucv_string_get(path));
if (fd < 0)
err_return(errno, NULL);
err = bpf_obj_get_info_by_fd(fd, &info, &len);
if (err) {
close(fd);
err_return(errno, NULL);
}
return uc_bpf_map_create(fd, info.key_size, info.value_size, true);
}
static uc_value_t *
uc_bpf_open_program(uc_vm_t *vm, size_t nargs)
{
uc_value_t *path = uc_fn_arg(0);
struct uc_bpf_fd *f;
int fd;
if (ucv_type(path) != UC_STRING)
err_return(EINVAL, "module path");
fd = bpf_obj_get(ucv_string_get(path));
if (fd < 0)
err_return(errno, NULL);
f = xalloc(sizeof(*f));
f->fd = fd;
f->close = true;
return uc_resource_new(program_type, f);
}
static uc_value_t *
uc_bpf_module_get_maps(uc_vm_t *vm, size_t nargs)
{
struct bpf_object *obj = uc_fn_thisval("bpf.module");
struct bpf_map *map = NULL;
uc_value_t *rv;
int i = 0;
if (!obj)
err_return(EINVAL, NULL);
rv = ucv_array_new(vm);
bpf_object__for_each_map(map, obj)
ucv_array_set(rv, i++, ucv_string_new(bpf_map__name(map)));
return rv;
}
static uc_value_t *
uc_bpf_module_get_map(uc_vm_t *vm, size_t nargs)
{
struct bpf_object *obj = uc_fn_thisval("bpf.module");
struct bpf_map *map;
uc_value_t *name = uc_fn_arg(0);
int fd;
if (!obj || ucv_type(name) != UC_STRING)
err_return(EINVAL, NULL);
map = bpf_object__find_map_by_name(obj, ucv_string_get(name));
if (!map)
err_return(errno, NULL);
fd = bpf_map__fd(map);
if (fd < 0)
err_return(EINVAL, NULL);
return uc_bpf_map_create(fd, bpf_map__key_size(map), bpf_map__value_size(map), false);
}
static uc_value_t *
uc_bpf_module_get_programs(uc_vm_t *vm, size_t nargs)
{
struct bpf_object *obj = uc_fn_thisval("bpf.module");
struct bpf_program *prog = NULL;
uc_value_t *rv;
int i = 0;
if (!obj)
err_return(EINVAL, NULL);
rv = ucv_array_new(vm);
bpf_object__for_each_program(prog, obj)
ucv_array_set(rv, i++, ucv_string_new(bpf_program__name(prog)));
return rv;
}
static uc_value_t *
uc_bpf_module_get_program(uc_vm_t *vm, size_t nargs)
{
struct bpf_object *obj = uc_fn_thisval("bpf.module");
struct bpf_program *prog;
uc_value_t *name = uc_fn_arg(0);
struct uc_bpf_fd *f;
int fd;
if (!obj || !name || ucv_type(name) != UC_STRING)
err_return(EINVAL, NULL);
prog = bpf_object__find_program_by_name(obj, ucv_string_get(name));
if (!prog)
err_return(errno, NULL);
fd = bpf_program__fd(prog);
if (fd < 0)
err_return(EINVAL, NULL);
f = xalloc(sizeof(*f));
f->fd = fd;
return uc_resource_new(program_type, f);
}
static void *
uc_bpf_map_arg(uc_value_t *val, const char *kind, unsigned int size)
{
static union {
uint32_t u32;
uint64_t u64;
} val_int;
switch (ucv_type(val)) {
case UC_INTEGER:
if (size == 4)
val_int.u32 = ucv_int64_get(val);
else if (size == 8)
val_int.u64 = ucv_int64_get(val);
else
break;
return &val_int;
case UC_STRING:
if (size != ucv_string_length(val))
break;
return ucv_string_get(val);
default:
err_return(EINVAL, "%s type", kind);
}
err_return(EINVAL, "%s size mismatch (expected: %d)", kind, size);
}
static uc_value_t *
uc_bpf_map_get(uc_vm_t *vm, size_t nargs)
{
struct uc_bpf_map *map = uc_fn_thisval("bpf.map");
uc_value_t *a_key = uc_fn_arg(0);
void *key, *val;
if (!map)
err_return(EINVAL, NULL);
key = uc_bpf_map_arg(a_key, "key", map->key_size);
if (!key)
return NULL;
val = alloca(map->val_size);
if (bpf_map_lookup_elem(map->fd.fd, key, val))
return NULL;
return ucv_string_new_length(val, map->val_size);
}
static uc_value_t *
uc_bpf_map_set(uc_vm_t *vm, size_t nargs)
{
struct uc_bpf_map *map = uc_fn_thisval("bpf.map");
uc_value_t *a_key = uc_fn_arg(0);
uc_value_t *a_val = uc_fn_arg(1);
uc_value_t *a_flags = uc_fn_arg(2);
uint64_t flags;
void *key, *val;
if (!map)
err_return(EINVAL, NULL);
key = uc_bpf_map_arg(a_key, "key", map->key_size);
if (!key)
return NULL;
val = uc_bpf_map_arg(a_val, "value", map->val_size);
if (!val)
return NULL;
if (!a_flags)
flags = BPF_ANY;
else if (ucv_type(a_flags) != UC_INTEGER)
err_return(EINVAL, "flags");
else
flags = ucv_int64_get(a_flags);
if (bpf_map_update_elem(map->fd.fd, key, val, flags))
return NULL;
return ucv_string_new_length(val, map->val_size);
}
static uc_value_t *
uc_bpf_map_delete(uc_vm_t *vm, size_t nargs)
{
struct uc_bpf_map *map = uc_fn_thisval("bpf.map");
uc_value_t *a_key = uc_fn_arg(0);
uc_value_t *a_return = uc_fn_arg(1);
void *key, *val = NULL;
int ret;
if (!map)
err_return(EINVAL, NULL);
key = uc_bpf_map_arg(a_key, "key", map->key_size);
if (!key)
return NULL;
if (!ucv_is_truish(a_return)) {
ret = bpf_map_delete_elem(map->fd.fd, key);
return ucv_boolean_new(ret == 0);
}
val = alloca(map->val_size);
if (bpf_map_lookup_and_delete_elem(map->fd.fd, key, val))
return NULL;
return ucv_string_new_length(val, map->val_size);
}
static uc_value_t *
uc_bpf_map_delete_all(uc_vm_t *vm, size_t nargs)
{
struct uc_bpf_map *map = uc_fn_thisval("bpf.map");
uc_value_t *filter = uc_fn_arg(0);
bool has_next;
void *key, *next;
if (!map)
err_return(EINVAL, NULL);
key = alloca(map->key_size);
next = alloca(map->key_size);
has_next = !bpf_map_get_next_key(map->fd.fd, NULL, next);
while (has_next) {
bool skip = false;
memcpy(key, next, map->key_size);
has_next = !bpf_map_get_next_key(map->fd.fd, next, next);
if (ucv_is_callable(filter)) {
uc_value_t *rv;
uc_value_push(ucv_get(filter));
uc_value_push(ucv_string_new_length((const char *)key, map->key_size));
if (uc_call(1) != EXCEPTION_NONE)
break;
rv = uc_vm_stack_pop(vm);
if (!rv)
break;
skip = !ucv_is_truish(rv);
ucv_put(rv);
}
if (!skip)
bpf_map_delete_elem(map->fd.fd, key);
}
return TRUE;
}
static uc_value_t *
uc_bpf_map_iterator(uc_vm_t *vm, size_t nargs)
{
struct uc_bpf_map *map = uc_fn_thisval("bpf.map");
struct uc_bpf_map_iter *iter;
if (!map)
err_return(EINVAL, NULL);
iter = xalloc(sizeof(*iter) + map->key_size);
iter->fd = map->fd.fd;
iter->key_size = map->key_size;
iter->has_next = !bpf_map_get_next_key(iter->fd, NULL, &iter->key);
return uc_resource_new(map_iter_type, iter);
}
static uc_value_t *
uc_bpf_map_iter_next(uc_vm_t *vm, size_t nargs)
{
struct uc_bpf_map_iter *iter = uc_fn_thisval("bpf.map_iter");
uc_value_t *rv;
if (!iter->has_next)
return NULL;
rv = ucv_string_new_length((const char *)iter->key, iter->key_size);
iter->has_next = !bpf_map_get_next_key(iter->fd, &iter->key, &iter->key);
return rv;
}
static uc_value_t *
uc_bpf_map_iter_next_int(uc_vm_t *vm, size_t nargs)
{
struct uc_bpf_map_iter *iter = uc_fn_thisval("bpf.map_iter");
uint64_t intval;
uc_value_t *rv;
if (!iter->has_next)
return NULL;
if (iter->key_size == 4)
intval = *(uint32_t *)iter->key;
else if (iter->key_size == 8)
intval = *(uint64_t *)iter->key;
else
return NULL;
rv = ucv_int64_new(intval);
iter->has_next = !bpf_map_get_next_key(iter->fd, &iter->key, &iter->key);
return rv;
}
static uc_value_t *
uc_bpf_map_foreach(uc_vm_t *vm, size_t nargs)
{
struct uc_bpf_map *map = uc_fn_thisval("bpf.map");
uc_value_t *func = uc_fn_arg(0);
bool has_next;
void *key, *next;
bool ret = false;
key = alloca(map->key_size);
next = alloca(map->key_size);
has_next = !bpf_map_get_next_key(map->fd.fd, NULL, next);
while (has_next) {
uc_value_t *rv;
bool stop;
memcpy(key, next, map->key_size);
has_next = !bpf_map_get_next_key(map->fd.fd, next, next);
uc_value_push(ucv_get(func));
uc_value_push(ucv_string_new_length((const char *)key, map->key_size));
if (uc_call(1) != EXCEPTION_NONE)
break;
rv = uc_vm_stack_pop(vm);
stop = (ucv_type(rv) == UC_BOOLEAN && !ucv_boolean_get(rv));
ucv_put(rv);
if (stop)
break;
ret = true;
}
return ucv_boolean_new(ret);
}
static uc_value_t *
uc_bpf_obj_pin(uc_vm_t *vm, size_t nargs, const char *type)
{
struct uc_bpf_fd *f = uc_fn_thisval(type);
uc_value_t *path = uc_fn_arg(0);
if (ucv_type(path) != UC_STRING)
err_return(EINVAL, NULL);
if (bpf_obj_pin(f->fd, ucv_string_get(path)))
err_return(errno, NULL);
return TRUE;
}
static uc_value_t *
uc_bpf_program_pin(uc_vm_t *vm, size_t nargs)
{
return uc_bpf_obj_pin(vm, nargs, "bpf.program");
}
static uc_value_t *
uc_bpf_map_pin(uc_vm_t *vm, size_t nargs)
{
return uc_bpf_obj_pin(vm, nargs, "bpf.map");
}
static uc_value_t *
uc_bpf_set_tc_hook(uc_value_t *ifname, uc_value_t *type, uc_value_t *prio,
int fd)
{
DECLARE_LIBBPF_OPTS(bpf_tc_hook, hook);
DECLARE_LIBBPF_OPTS(bpf_tc_opts, attach_tc,
.handle = 1);
const char *type_str;
uint64_t prio_val;
if (ucv_type(ifname) != UC_STRING || ucv_type(type) != UC_STRING ||
ucv_type(prio) != UC_INTEGER)
err_return(EINVAL, NULL);
prio_val = ucv_int64_get(prio);
if (prio_val > 0xffff)
err_return(EINVAL, NULL);
type_str = ucv_string_get(type);
if (!strcmp(type_str, "ingress"))
hook.attach_point = BPF_TC_INGRESS;
else if (!strcmp(type_str, "egress"))
hook.attach_point = BPF_TC_EGRESS;
else
err_return(EINVAL, NULL);
hook.ifindex = if_nametoindex(ucv_string_get(ifname));
if (!hook.ifindex)
goto error;
bpf_tc_hook_create(&hook);
attach_tc.priority = prio_val;
if (bpf_tc_detach(&hook, &attach_tc) < 0 && fd < 0)
goto error;
if (fd < 0)
goto out;
attach_tc.prog_fd = fd;
if (bpf_tc_attach(&hook, &attach_tc) < 0)
goto error;
out:
return TRUE;
error:
if (fd >= 0)
err_return(ENOENT, NULL);
return NULL;
}
static uc_value_t *
uc_bpf_program_tc_attach(uc_vm_t *vm, size_t nargs)
{
struct uc_bpf_fd *f = uc_fn_thisval("bpf.program");
uc_value_t *ifname = uc_fn_arg(0);
uc_value_t *type = uc_fn_arg(1);
uc_value_t *prio = uc_fn_arg(2);
if (!f)
err_return(EINVAL, NULL);
return uc_bpf_set_tc_hook(ifname, type, prio, f->fd);
}
static uc_value_t *
uc_bpf_tc_detach(uc_vm_t *vm, size_t nargs)
{
uc_value_t *ifname = uc_fn_arg(0);
uc_value_t *type = uc_fn_arg(1);
uc_value_t *prio = uc_fn_arg(2);
return uc_bpf_set_tc_hook(ifname, type, prio, -1);
}
static int
uc_bpf_debug_print(enum libbpf_print_level level, const char *format,
va_list args)
{
char buf[256], *str = NULL;
uc_value_t *val;
va_list ap;
int size;
va_copy(ap, args);
size = vsnprintf(buf, sizeof(buf), format, ap);
va_end(ap);
if (size > 0 && (unsigned long)size < ARRAY_SIZE(buf) - 1) {
val = ucv_string_new(buf);
goto out;
}
if (vasprintf(&str, format, args) < 0)
return 0;
val = ucv_string_new(str);
free(str);
out:
uc_vm_stack_push(debug_vm, ucv_get(ucv_array_get(registry, 0)));
uc_vm_stack_push(debug_vm, ucv_int64_new(level));
uc_vm_stack_push(debug_vm, val);
if (uc_vm_call(debug_vm, false, 2) == EXCEPTION_NONE)
ucv_put(uc_vm_stack_pop(debug_vm));
return 0;
}
static uc_value_t *
uc_bpf_set_debug_handler(uc_vm_t *vm, size_t nargs)
{
uc_value_t *handler = uc_fn_arg(0);
if (handler && !ucv_is_callable(handler))
err_return(EINVAL, NULL);
debug_vm = vm;
libbpf_set_print(handler ? uc_bpf_debug_print : NULL);
ucv_array_set(registry, 0, ucv_get(handler));
return NULL;
}
static void
register_constants(uc_vm_t *vm, uc_value_t *scope)
{
#define ADD_CONST(x) ucv_object_add(scope, #x, ucv_int64_new(x))
ADD_CONST(BPF_PROG_TYPE_SCHED_CLS);
ADD_CONST(BPF_PROG_TYPE_SCHED_ACT);
ADD_CONST(BPF_ANY);
ADD_CONST(BPF_NOEXIST);
ADD_CONST(BPF_EXIST);
ADD_CONST(BPF_F_LOCK);
}
static const uc_function_list_t module_fns[] = {
{ "get_map", uc_bpf_module_get_map },
{ "get_maps", uc_bpf_module_get_maps },
{ "get_programs", uc_bpf_module_get_programs },
{ "get_program", uc_bpf_module_get_program },
};
static void module_free(void *ptr)
{
struct bpf_object *obj = ptr;
bpf_object__close(obj);
}
static const uc_function_list_t map_fns[] = {
{ "pin", uc_bpf_map_pin },
{ "get", uc_bpf_map_get },
{ "set", uc_bpf_map_set },
{ "delete", uc_bpf_map_delete },
{ "delete_all", uc_bpf_map_delete_all },
{ "foreach", uc_bpf_map_foreach },
{ "iterator", uc_bpf_map_iterator },
};
static void uc_bpf_fd_free(void *ptr)
{
struct uc_bpf_fd *f = ptr;
if (f->close)
close(f->fd);
free(f);
}
static const uc_function_list_t map_iter_fns[] = {
{ "next", uc_bpf_map_iter_next },
{ "next_int", uc_bpf_map_iter_next_int },
};
static const uc_function_list_t prog_fns[] = {
{ "pin", uc_bpf_program_pin },
{ "tc_attach", uc_bpf_program_tc_attach },
};
static const uc_function_list_t global_fns[] = {
{ "error", uc_bpf_error },
{ "set_debug_handler", uc_bpf_set_debug_handler },
{ "open_module", uc_bpf_open_module },
{ "open_map", uc_bpf_open_map },
{ "open_program", uc_bpf_open_program },
{ "tc_detach", uc_bpf_tc_detach },
};
void uc_module_init(uc_vm_t *vm, uc_value_t *scope)
{
uc_function_list_register(scope, global_fns);
register_constants(vm, scope);
registry = ucv_array_new(vm);
uc_vm_registry_set(vm, "bpf.registry", registry);
module_type = uc_type_declare(vm, "bpf.module", module_fns, module_free);
map_type = uc_type_declare(vm, "bpf.map", map_fns, uc_bpf_fd_free);
map_iter_type = uc_type_declare(vm, "bpf.map_iter", map_iter_fns, free);
program_type = uc_type_declare(vm, "bpf.program", prog_fns, uc_bpf_fd_free);
}