Files
NetworkManager/src/core/nm-firewall-utils.c

832 lines
29 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2004 - 2016 Red Hat, Inc.
* Copyright (C) 2005 - 2008 Novell, Inc.
*/
#include "src/core/nm-default-daemon.h"
#include "nm-firewall-utils.h"
#include "libnm-glib-aux/nm-str-buf.h"
#include "libnm-glib-aux/nm-io-utils.h"
#include "libnm-platform/nm-platform.h"
#include "nm-config.h"
#include "NetworkManagerUtils.h"
/*****************************************************************************/
static const struct {
const char *name;
const char *path;
} FirewallBackends[] = {
[NM_FIREWALL_BACKEND_NONE - 1] =
{
.name = "none",
},
[NM_FIREWALL_BACKEND_NFTABLES - 1] =
{
.name = "nftables",
.path = NFT_PATH,
},
[NM_FIREWALL_BACKEND_IPTABLES - 1] =
{
.name = "iptables",
.path = IPTABLES_PATH,
},
};
/*****************************************************************************/
#define _SHARE_IPTABLES_SUBNET_TO_STR_LEN (INET_ADDRSTRLEN + 1 + 2 + 1)
static const char *
_share_iptables_subnet_to_str(char buf[static _SHARE_IPTABLES_SUBNET_TO_STR_LEN],
in_addr_t addr,
guint8 plen)
{
char buf_addr[INET_ADDRSTRLEN];
in_addr_t netmask;
int l;
netmask = nm_ip4_addr_netmask_from_prefix(plen);
l = g_snprintf(buf,
_SHARE_IPTABLES_SUBNET_TO_STR_LEN,
"%s/%u",
nm_inet4_ntop(addr & netmask, buf_addr),
plen);
nm_assert(l < _SHARE_IPTABLES_SUBNET_TO_STR_LEN);
return buf;
}
static char *
_share_iptables_get_name(gboolean is_iptables_chain, const char *prefix, const char *ip_iface)
{
NMStrBuf strbuf = NM_STR_BUF_INIT(NM_UTILS_GET_NEXT_REALLOC_SIZE_40, FALSE);
gsize ip_iface_len;
nm_assert(prefix);
nm_assert(ip_iface);
/* This function is used to generate iptables chain names and comments.
* Chain names must be shorter than 29 chars. Comments don't have this
* limitation.
*
* Below we sanitize the ip_iface. If it's all benign, we use
* - either "-$IP_IFACE" (at most 16 chars)
* - otherwise, we base64 encode the name as "$(base64 $IP_IFACE)", at
* most 20 chars.
*
* Since for benign names we already add a '-', prefix probably should not
* contain a '-'. The '-' is necessary to distinguish between base64 encoding
* an plain name.
*
* That means, for chain names the prefix must be at most 8 chars long. */
nm_assert(!is_iptables_chain || (strlen(prefix) <= 8));
nm_str_buf_append(&strbuf, prefix);
ip_iface_len = strlen(ip_iface);
G_STATIC_ASSERT_EXPR(NMP_IFNAMSIZ == 16);
if (ip_iface_len >= NMP_IFNAMSIZ) {
nm_assert_not_reached();
ip_iface_len = NMP_IFNAMSIZ - 1;
}
if (NM_STRCHAR_ALL(ip_iface,
ch,
(ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'z')
|| (ch >= 'A' && ch <= 'Z') || NM_IN_SET(ch, '.', '_', '-', '+'))) {
nm_str_buf_append_c(&strbuf, '-');
nm_str_buf_append(&strbuf, ip_iface);
} else {
gs_free char *s = NULL;
s = g_base64_encode((const guchar *) ip_iface, ip_iface_len);
nm_str_buf_append(&strbuf, s);
}
return nm_str_buf_finalize(&strbuf, NULL);
}
/*****************************************************************************/
static gboolean
_share_iptables_call_v(const char *const *argv)
{
gs_free_error GError *error = NULL;
gs_free char *argv_str = NULL;
int status;
nm_log_dbg(LOGD_SHARING, "iptables: %s", (argv_str = g_strjoinv(" ", (char **) argv)));
if (!g_spawn_sync("/",
(char **) argv,
(char **) NM_PTRARRAY_EMPTY(const char *),
G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL,
NULL,
NULL,
NULL,
NULL,
&status,
&error)) {
nm_log_warn(LOGD_SHARING,
"iptables: error executing command %s: %s",
argv[0],
error->message);
return FALSE;
}
if (!g_spawn_check_exit_status(status, &error)) {
nm_log_warn(LOGD_SHARING, "iptables: command %s failed: %s", argv[0], error->message);
return FALSE;
}
return TRUE;
}
#define _share_iptables_call(...) _share_iptables_call_v(NM_MAKE_STRV(__VA_ARGS__))
static gboolean
_share_iptables_chain_op(const char *table, const char *chain, const char *op)
{
return _share_iptables_call("" IPTABLES_PATH "", "--table", table, op, chain);
}
static gboolean
_share_iptables_chain_delete(const char *table, const char *chain)
{
_share_iptables_chain_op(table, chain, "--flush");
return _share_iptables_chain_op(table, chain, "--delete-chain");
}
static gboolean
_share_iptables_chain_add(const char *table, const char *chain)
{
if (_share_iptables_chain_op(table, chain, "--new-chain"))
return TRUE;
_share_iptables_chain_delete(table, chain);
return _share_iptables_chain_op(table, chain, "--new-chain");
}
static void
_share_iptables_set_masquerade_sync(gboolean up, const char *ip_iface, in_addr_t addr, guint8 plen)
{
char str_subnet[_SHARE_IPTABLES_SUBNET_TO_STR_LEN];
gs_free char *comment_name = NULL;
comment_name = _share_iptables_get_name(FALSE, "nm-shared", ip_iface);
_share_iptables_subnet_to_str(str_subnet, addr, plen);
_share_iptables_call("" IPTABLES_PATH "",
"--table",
"nat",
up ? "--insert" : "--delete",
"POSTROUTING",
"--source",
str_subnet,
"!",
"--destination",
str_subnet,
"--jump",
"MASQUERADE",
"-m",
"comment",
"--comment",
comment_name);
}
static void
_share_iptables_set_shared_chains_add(const char *chain_input,
const char *chain_forward,
const char *ip_iface,
in_addr_t addr,
guint plen)
{
const char *const input_params[][2] = {
{
"tcp",
"67",
},
{
"udp",
"67",
},
{
"tcp",
"53",
},
{
"udp",
"53",
},
};
char str_subnet[_SHARE_IPTABLES_SUBNET_TO_STR_LEN];
int i;
_share_iptables_subnet_to_str(str_subnet, addr, plen);
_share_iptables_chain_add("filter", chain_input);
for (i = 0; i < (int) G_N_ELEMENTS(input_params); i++) {
_share_iptables_call("" IPTABLES_PATH "",
"--table",
"filter",
"--append",
chain_input,
"--protocol",
input_params[i][0],
"--destination-port",
input_params[i][1],
"--jump",
"ACCEPT");
}
_share_iptables_chain_add("filter", chain_forward);
_share_iptables_call("" IPTABLES_PATH "",
"--table",
"filter",
"--append",
chain_forward,
"--destination",
str_subnet,
"--out-interface",
ip_iface,
"--match",
"state",
"--state",
"ESTABLISHED,RELATED",
"--jump",
"ACCEPT");
_share_iptables_call("" IPTABLES_PATH "",
"--table",
"filter",
"--append",
chain_forward,
"--source",
str_subnet,
"--in-interface",
ip_iface,
"--jump",
"ACCEPT");
_share_iptables_call("" IPTABLES_PATH "",
"--table",
"filter",
"--append",
chain_forward,
"--in-interface",
ip_iface,
"--out-interface",
ip_iface,
"--jump",
"ACCEPT");
_share_iptables_call("" IPTABLES_PATH "",
"--table",
"filter",
"--append",
chain_forward,
"--out-interface",
ip_iface,
"--jump",
"REJECT");
_share_iptables_call("" IPTABLES_PATH "",
"--table",
"filter",
"--append",
chain_forward,
"--in-interface",
ip_iface,
"--jump",
"REJECT");
}
static void
_share_iptables_set_shared_chains_delete(const char *chain_input, const char *chain_forward)
{
_share_iptables_chain_delete("filter", chain_input);
_share_iptables_chain_delete("filter", chain_forward);
}
static void
_share_iptables_set_shared_sync(gboolean up, const char *ip_iface, in_addr_t addr, guint plen)
{
gs_free char *comment_name = NULL;
gs_free char *chain_input = NULL;
gs_free char *chain_forward = NULL;
comment_name = _share_iptables_get_name(FALSE, "nm-shared", ip_iface);
chain_input = _share_iptables_get_name(TRUE, "nm-sh-in", ip_iface);
chain_forward = _share_iptables_get_name(TRUE, "nm-sh-fw", ip_iface);
if (up)
_share_iptables_set_shared_chains_add(chain_input, chain_forward, ip_iface, addr, plen);
_share_iptables_call("" IPTABLES_PATH "",
"--table",
"filter",
up ? "--insert" : "--delete",
"INPUT",
"--in-interface",
ip_iface,
"--jump",
chain_input,
"-m",
"comment",
"--comment",
comment_name);
_share_iptables_call("" IPTABLES_PATH "",
"--table",
"filter",
up ? "--insert" : "--delete",
"FORWARD",
"--jump",
chain_forward,
"-m",
"comment",
"--comment",
comment_name);
if (!up)
_share_iptables_set_shared_chains_delete(chain_input, chain_forward);
}
/*****************************************************************************/
typedef struct {
GTask *task;
GSubprocess *subprocess;
GSource *timeout_source;
GCancellable *intern_cancellable;
char *identifier;
gulong cancellable_id;
} FwNftCallData;
static void
_fw_nft_call_data_free(FwNftCallData *call_data, GError *error_take)
{
nm_clear_g_signal_handler(g_task_get_cancellable(call_data->task), &call_data->cancellable_id);
nm_clear_g_cancellable(&call_data->intern_cancellable);
nm_clear_g_source_inst(&call_data->timeout_source);
if (error_take)
g_task_return_error(call_data->task, error_take);
else
g_task_return_boolean(call_data->task, TRUE);
g_object_unref(call_data->task);
nm_g_object_unref(call_data->subprocess);
g_free(call_data->identifier);
nm_g_slice_free(call_data);
}
static void
_fw_nft_call_communicate_cb(GObject *source, GAsyncResult *result, gpointer user_data)
{
FwNftCallData *call_data = user_data;
gs_free_error GError *error = NULL;
gs_unref_bytes GBytes *stdout_buf = NULL;
gs_unref_bytes GBytes *stderr_buf = NULL;
nm_assert(source == (gpointer) call_data->subprocess);
if (!g_subprocess_communicate_finish(G_SUBPROCESS(source),
result,
&stdout_buf,
&stderr_buf,
&error)) {
/* on any error, the process might still be running. We need to abort it in
* the background... */
if (!nm_utils_error_is_cancelled(error)) {
nm_log_dbg(LOGD_SHARING,
"firewall: nft[%s]: communication failed: %s. Kill process",
call_data->identifier,
error->message);
} else if (!call_data->timeout_source) {
nm_log_dbg(LOGD_SHARING,
"firewall: ntf[%s]: communication timed out. Kill process",
call_data->identifier);
nm_clear_error(&error);
nm_utils_error_set(&error, NM_UTILS_ERROR_UNKNOWN, "timeout communicating with nft");
} else {
nm_log_dbg(LOGD_SHARING,
"firewall: ntf[%s]: communication cancelled. Kill process",
call_data->identifier);
}
{
_nm_unused nm_auto_pop_gmaincontext GMainContext *main_context =
nm_g_main_context_push_thread_default_if_necessary(NULL);
nm_shutdown_wait_obj_register_object(call_data->subprocess, "nft-terminate");
G_STATIC_ASSERT_EXPR(200 < NM_SHUTDOWN_TIMEOUT_ADDITIONAL_MSEC * 2 / 3);
nm_g_subprocess_terminate_in_background(call_data->subprocess, 200);
}
} else if (g_subprocess_get_successful(call_data->subprocess)) {
nm_log_dbg(LOGD_SHARING, "firewall: nft[%s]: command successful", call_data->identifier);
} else {
char buf[NM_UTILS_GET_PROCESS_EXIT_STATUS_BUF_LEN];
gs_free char *ss_stdout = NULL;
gs_free char *ss_stderr = NULL;
gboolean print_stdout = (stdout_buf && g_bytes_get_size(stdout_buf) > 0);
gboolean print_stderr = (stderr_buf && g_bytes_get_size(stderr_buf) > 0);
int status;
status = g_subprocess_get_status(call_data->subprocess);
nm_utils_get_process_exit_status_desc_buf(status, buf, sizeof(buf));
nm_log_warn(LOGD_SHARING,
"firewall: nft[%s]: command %s:%s%s%s%s%s%s%s",
call_data->identifier,
buf,
print_stdout || print_stderr ? "" : " unknown reason",
NM_PRINT_FMT_QUOTED(
print_stdout,
" (stdout: \"",
nm_utils_buf_utf8safe_escape_bytes(stdout_buf,
NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL,
&ss_stdout),
"\")",
""),
NM_PRINT_FMT_QUOTED(
print_stderr,
" (stderr: \"",
nm_utils_buf_utf8safe_escape_bytes(stderr_buf,
NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL,
&ss_stderr),
"\")",
""));
nm_utils_error_set(&error, NM_UTILS_ERROR_COMMAND_FAILED, "nft command %s", buf);
}
_fw_nft_call_data_free(call_data, g_steal_pointer(&error));
}
static void
_fw_nft_call_cancelled_cb(GCancellable *cancellable, gpointer user_data)
{
FwNftCallData *call_data = user_data;
if (call_data->cancellable_id == 0)
return;
nm_log_dbg(LOGD_SHARING, "firewall: nft[%s]: operation cancelled", call_data->identifier);
nm_clear_g_signal_handler(g_task_get_cancellable(call_data->task), &call_data->cancellable_id);
nm_clear_g_cancellable(&call_data->intern_cancellable);
}
static gboolean
_fw_nft_call_timeout_cb(gpointer user_data)
{
FwNftCallData *call_data = user_data;
nm_clear_g_source_inst(&call_data->timeout_source);
nm_log_dbg(LOGD_SHARING,
"firewall: nft[%s]: cancel operation after timeout",
call_data->identifier);
nm_clear_g_cancellable(&call_data->intern_cancellable);
return G_SOURCE_CONTINUE;
}
void
nm_firewall_nft_call(GBytes *stdin_buf,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer callback_user_data)
{
gs_unref_object GSubprocessLauncher *subprocess_launcher = NULL;
gs_free_error GError *error = NULL;
FwNftCallData *call_data;
gs_free char *ss1 = NULL;
call_data = g_slice_new(FwNftCallData);
*call_data = (FwNftCallData){
.task =
nm_g_task_new(NULL, cancellable, nm_firewall_nft_call, callback, callback_user_data),
.subprocess = NULL,
.timeout_source = NULL,
};
nm_log_trace(LOGD_SHARING,
"firewall: nft: call command: [ '%s' ]",
nm_utils_buf_utf8safe_escape_bytes(stdin_buf,
NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL,
&ss1));
if (cancellable) {
call_data->cancellable_id = g_cancellable_connect(cancellable,
G_CALLBACK(_fw_nft_call_cancelled_cb),
call_data,
NULL);
if (call_data->cancellable_id == 0) {
nm_log_dbg(LOGD_SHARING, "firewall: nft: already cancelled");
nm_utils_error_set_cancelled(&error, FALSE, NULL);
_fw_nft_call_data_free(call_data, g_steal_pointer(&error));
return;
}
}
subprocess_launcher =
g_subprocess_launcher_new(G_SUBPROCESS_FLAGS_STDIN_PIPE | G_SUBPROCESS_FLAGS_STDOUT_PIPE
| G_SUBPROCESS_FLAGS_STDERR_PIPE);
g_subprocess_launcher_set_environ(subprocess_launcher, NM_STRV_EMPTY());
call_data->subprocess = g_subprocess_launcher_spawnv(subprocess_launcher,
NM_MAKE_STRV(NFT_PATH, "-f", "-"),
&error);
if (!call_data->subprocess) {
nm_log_dbg(LOGD_SHARING, "firewall: nft: spawning nft failed: %s", error->message);
_fw_nft_call_data_free(call_data, g_steal_pointer(&error));
return;
}
call_data->identifier = g_strdup(g_subprocess_get_identifier(call_data->subprocess));
nm_log_dbg(LOGD_SHARING, "firewall: nft[%s]: communicate with nft", call_data->identifier);
nm_shutdown_wait_obj_register_object(call_data->task, "nft-call");
call_data->intern_cancellable = g_cancellable_new(),
g_subprocess_communicate_async(call_data->subprocess,
stdin_buf,
call_data->intern_cancellable,
_fw_nft_call_communicate_cb,
call_data);
call_data->timeout_source =
nm_g_source_attach(nm_g_timeout_source_new((NM_SHUTDOWN_TIMEOUT_1500_MSEC * 2) / 3,
G_PRIORITY_DEFAULT,
_fw_nft_call_timeout_cb,
call_data,
NULL),
g_task_get_context(call_data->task));
}
gboolean
nm_firewall_nft_call_finish(GAsyncResult *result, GError **error)
{
g_return_val_if_fail(nm_g_task_is_valid(result, NULL, nm_firewall_nft_call), FALSE);
return g_task_propagate_boolean(G_TASK(result), error);
}
/*****************************************************************************/
typedef struct {
GMainLoop *loop;
GError **error;
gboolean success;
} FwNftCallSyncData;
static void
_fw_nft_call_sync_done(GObject *source, GAsyncResult *result, gpointer user_data)
{
FwNftCallSyncData *data = user_data;
data->success = nm_firewall_nft_call_finish(result, data->error);
g_main_loop_quit(data->loop);
}
static gboolean
_fw_nft_call_sync(GBytes *stdin_buf, GError **error)
{
nm_auto_pop_and_unref_gmaincontext GMainContext *main_context =
nm_g_main_context_push_thread_default(g_main_context_new());
nm_auto_unref_gmainloop GMainLoop *main_loop = g_main_loop_new(main_context, FALSE);
FwNftCallSyncData data = (FwNftCallSyncData){
.loop = main_loop,
.error = error,
};
nm_firewall_nft_call(stdin_buf, NULL, _fw_nft_call_sync_done, &data);
g_main_loop_run(main_loop);
return data.success;
}
/*****************************************************************************/
#define _append(p_strbuf, fmt, ...) nm_str_buf_append_printf((p_strbuf), "" fmt "\n", ##__VA_ARGS__)
static GBytes *
_fw_nft_set_shared_construct(gboolean up, const char *ip_iface, in_addr_t addr, guint8 plen)
{
nm_auto_str_buf NMStrBuf strbuf = NM_STR_BUF_INIT(NM_UTILS_GET_NEXT_REALLOC_SIZE_1000, FALSE);
gs_free char *table_name = NULL;
char str_subnet[_SHARE_IPTABLES_SUBNET_TO_STR_LEN];
table_name = _share_iptables_get_name(FALSE, "nm-shared", ip_iface);
_share_iptables_subnet_to_str(str_subnet, addr, plen);
_append(&strbuf, "add table ip %s", table_name);
_append(&strbuf, "%s table ip %s", up ? "flush" : "delete", table_name);
if (up) {
_append(&strbuf,
"add chain ip %s nat_postrouting {"
" type nat hook postrouting priority 100; policy accept; "
"};",
table_name);
_append(&strbuf,
"add rule ip %s nat_postrouting ip saddr %s ip daddr != %s masquerade;",
table_name,
str_subnet,
str_subnet);
/* This filter_input chain serves no real purpose, because "accept" only stops
* evaluation of the current rule. It cannot fully accept the packet. Since
* this chain has no other rules, it is useless in this form.
*
* _append(&strbuf,
* "add chain ip %s filter_input {"
* " type filter hook input priority 0; policy accept; "
* "};",
* table_name);
* _append(&strbuf, "add rule ip %s filter_input tcp dport { 67, 53 } accept;", table_name);
* _append(&strbuf, "add rule ip %s filter_input udp dport { 67, 53 } accept;", table_name);
*/
_append(&strbuf,
"add chain ip %s filter_forward {"
" type filter hook forward priority 0; policy accept; "
"};",
table_name);
_append(&strbuf,
"add rule ip %s filter_forward ip daddr %s oifname \"%s\" "
" ct state { established, related } accept;",
table_name,
str_subnet,
ip_iface);
_append(&strbuf,
"add rule ip %s filter_forward ip saddr %s iifname \"%s\" accept;",
table_name,
str_subnet,
ip_iface);
_append(&strbuf,
"add rule ip %s filter_forward iifname \"%s\" oifname \"%s\" accept;",
table_name,
ip_iface,
ip_iface);
_append(&strbuf,
"add rule ip %s filter_forward iifname \"%s\" reject;",
table_name,
ip_iface);
_append(&strbuf,
"add rule ip %s filter_forward oifname \"%s\" reject;",
table_name,
ip_iface);
}
return nm_str_buf_finalize_to_gbytes(&strbuf);
}
/*****************************************************************************/
struct _NMFirewallConfig {
char *ip_iface;
in_addr_t addr;
guint8 plen;
};
NMFirewallConfig *
nm_firewall_config_new_shared(const char *ip_iface, in_addr_t addr, guint8 plen)
{
NMFirewallConfig *self;
nm_assert(ip_iface);
nm_assert(addr != 0u);
nm_assert(plen <= 32);
self = g_slice_new(NMFirewallConfig);
*self = (NMFirewallConfig){
.ip_iface = g_strdup(ip_iface),
.addr = addr,
.plen = plen,
};
return self;
}
void
nm_firewall_config_free(NMFirewallConfig *self)
{
if (!self)
return;
g_free(self->ip_iface);
nm_g_slice_free(self);
}
/*****************************************************************************/
void
nm_firewall_config_apply_sync(NMFirewallConfig *self, gboolean up)
{
switch (nm_firewall_utils_get_backend()) {
case NM_FIREWALL_BACKEND_IPTABLES:
_share_iptables_set_masquerade_sync(up, self->ip_iface, self->addr, self->plen);
_share_iptables_set_shared_sync(up, self->ip_iface, self->addr, self->plen);
break;
case NM_FIREWALL_BACKEND_NFTABLES:
{
gs_unref_bytes GBytes *stdin_buf = NULL;
stdin_buf = _fw_nft_set_shared_construct(up, self->ip_iface, self->addr, self->plen);
_fw_nft_call_sync(stdin_buf, NULL);
break;
}
case NM_FIREWALL_BACKEND_NONE:
break;
default:
nm_assert_not_reached();
break;
}
}
/*****************************************************************************/
static NMFirewallBackend
_firewall_backend_detect(void)
{
if (g_file_test(NFT_PATH, G_FILE_TEST_IS_EXECUTABLE))
return NM_FIREWALL_BACKEND_NFTABLES;
if (g_file_test(IPTABLES_PATH, G_FILE_TEST_IS_EXECUTABLE))
return NM_FIREWALL_BACKEND_IPTABLES;
return NM_FIREWALL_BACKEND_NFTABLES;
}
NMFirewallBackend
nm_firewall_utils_get_backend(void)
{
static int backend = NM_FIREWALL_BACKEND_UNKNOWN;
int b;
again:
b = g_atomic_int_get(&backend);
if (b == NM_FIREWALL_BACKEND_UNKNOWN) {
gs_free char *conf_value = NULL;
gboolean detect;
int i;
conf_value =
nm_config_data_get_value(NM_CONFIG_GET_DATA_ORIG,
NM_CONFIG_KEYFILE_GROUP_MAIN,
NM_CONFIG_KEYFILE_KEY_MAIN_FIREWALL_BACKEND,
NM_CONFIG_GET_VALUE_STRIP | NM_CONFIG_GET_VALUE_NO_EMPTY);
if (conf_value) {
for (i = 0; i < (int) G_N_ELEMENTS(FirewallBackends); i++) {
if (!g_ascii_strcasecmp(conf_value, FirewallBackends[i].name)) {
b = (i + 1);
break;
}
}
}
detect = (b == NM_FIREWALL_BACKEND_UNKNOWN);
if (detect)
b = _firewall_backend_detect();
nm_assert(NM_IN_SET(b,
NM_FIREWALL_BACKEND_NONE,
NM_FIREWALL_BACKEND_IPTABLES,
NM_FIREWALL_BACKEND_NFTABLES));
if (!g_atomic_int_compare_and_exchange(&backend, NM_FIREWALL_BACKEND_UNKNOWN, b))
goto again;
nm_log_dbg(LOGD_SHARING,
"firewall: use %s backend%s%s%s%s%s%s%s",
FirewallBackends[b - 1].name,
NM_PRINT_FMT_QUOTED(FirewallBackends[b - 1].path,
" (",
FirewallBackends[b - 1].path,
")",
""),
detect ? " (detected)" : "",
NM_PRINT_FMT_QUOTED(detect && conf_value,
" (invalid setting \"",
conf_value,
"\")",
""));
}
nm_assert(NM_IN_SET(b,
NM_FIREWALL_BACKEND_NONE,
NM_FIREWALL_BACKEND_IPTABLES,
NM_FIREWALL_BACKEND_NFTABLES));
return b;
}