picnoir
/
Systemd
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

resolve-tool: provide resolvconf(8) compatibility 

This turns resolve-tool into a multi-call binary. When invoked as
"resolvconf" it provides minimal compatibility with the resolvconf(8)
tool of various distributions (and FreeBSD as it appears).

This new interface understands to varying degrees features of the two
major implementations of resolvconf(8): Debian's original one and
"openresolv". Specifically:

Fully supported:

        -a -d (supported by all implementations)
        -f    (introduced by openresolv)

Somewhat supported:

        -x    (introduced by openresolv, mapped to a '~.' domain entry)

Unsupported and ignored:

        -m -p (introduced by openresolv, not really necessary for us)

Unsupported and resulting in failure:
        -u    (supported by all other implementations)
        -I -i -l -R -r -v -V
              (all introduced by openresolv)
        --enable-updates --disable-updates --updates-are-enabled
              (specific to Debian's implementation)

Of course, resolvconf(8) is a tool with multiple backends, in our
implementation systemd-resolved is the only backend.

Fixes: #7202
This commit is contained in:
Lennart Poettering 2018-02-27 17:48:54 +01:00
parent 6cc7e918ff
commit 088c136384
8 changed files with 388 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
meson.build
View File

@ -1632,6 +1632,10 @@ if conf.get('ENABLE_RESOLVE') == 1
install_rpath : rootlibexecdir,
install : true)
public_programs += [exe]
meson.add_install_script(meson_make_symlink,
join_paths(bindir, 'systemd-resolve'),
join_paths(rootsbindir, 'resolvconf'))
endif
if conf.get('ENABLE_LOGIND') == 1

7
src/resolve/meson.build
View File

@ -80,7 +80,12 @@ systemd_resolved_sources = files('''
resolved-etc-hosts.c
'''.split())
systemd_resolve_sources = files('resolve-tool.c')
systemd_resolve_sources = files('''
resolvconf-compat.c
resolvconf-compat.h
resolve-tool.c
resolve-tool.h
'''.split())
############################################################

312
src/resolve/resolvconf-compat.c Normal file
View File

@ -0,0 +1,312 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <getopt.h>
#include <net/if.h>
#include "alloc-util.h"
#include "def.h"
#include "dns-domain.h"
#include "extract-word.h"
#include "fileio.h"
#include "parse-util.h"
#include "resolvconf-compat.h"
#include "resolve-tool.h"
#include "resolved-def.h"
#include "string-util.h"
#include "strv.h"
static void resolvconf_help(void) {
printf("%1$s -a INTERFACE < FILE\n"
"%1$s -d INTERFACE\n"
"\n"
"Register DNS server and domain configuration with systemd-resolved.\n\n"
" -h --help Show this help\n"
" --version Show package version\n"
" -a Register per-interface DNS server and domain data\n"
" -d Unregister per-interface DNS server and domain data\n"
" -f Ignore if specified interface does not exist\n"
" -x Send DNS traffic preferably over this interface\n"
"\n"
"This is a compatibility alias for the systemd-resolve(1) tool, providing native\n"
"command line compatibility with the resolvconf(8) tool of various Linux\n"
"distributions and BSD systems. Some options supported by other implementations\n"
"are not supported and are ignored: -m, -p. Various options supported by other\n"
"implementations are not supported and will cause the invocation to fail: -u,\n"
"-I, -i, -l, -R, -r, -v, -V, --enable-updates, --disable-updates,\n"
"--updates-are-enabled.\n"
, program_invocation_short_name);
}
static int parse_nameserver(const char *string) {
int r;
assert(string);
for (;;) {
_cleanup_free_ char *word = NULL;
struct in_addr_data data, *n;
int ifindex = 0;
r = extract_first_word(&string, &word, NULL, 0);
if (r < 0)
return r;
if (r == 0)
break;
r = in_addr_ifindex_from_string_auto(word, &data.family, &data.address, &ifindex);
if (r < 0)
return log_error_errno(r, "Failed to parse name server '%s': %m", word);
if (ifindex > 0 && ifindex != arg_ifindex) {
log_error("Name server interface '%s' does not match selected interface: %m", word);
return -EINVAL;
}
/* Some superficial filtering */
if (in_addr_is_null(data.family, &data.address))
continue;
if (data.family == AF_INET && data.address.in.s_addr == htobe32(INADDR_DNS_STUB)) /* resolved's own stub? */
continue;
n = reallocarray(arg_set_dns, arg_n_set_dns + 1, sizeof(struct in_addr_data));
if (!n)
return log_oom();
arg_set_dns = n;
arg_set_dns[arg_n_set_dns++] = data;
}
return 0;
}
static int parse_search_domain(const char *string) {
int r;
assert(string);
for (;;) {
_cleanup_free_ char *word = NULL;
r = extract_first_word(&string, &word, NULL, EXTRACT_QUOTES);
if (r < 0)
return r;
if (r == 0)
break;
r = dns_name_is_valid(word);
if (r < 0)
return log_error_errno(r, "Failed to validate specified domain '%s': %m", word);
if (r == 0) {
log_error("Domain not valid: %s", word);
return -EINVAL;
}
if (strv_push(&arg_set_domain, word) < 0)
return log_oom();
word = NULL;
}
return 0;
}
int resolvconf_parse_argv(int argc, char *argv[]) {
enum {
ARG_VERSION = 0x100,
ARG_ENABLE_UPDATES,
ARG_DISABLE_UPDATES,
ARG_UPDATES_ARE_ENABLED,
};
static const struct option options[] = {
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, ARG_VERSION },
/* The following are specific to Debian's original resolvconf */
{ "enable-updates", no_argument, NULL, ARG_ENABLE_UPDATES },
{ "disable-updates", no_argument, NULL, ARG_DISABLE_UPDATES },
{ "updates-are-enabled", no_argument, NULL, ARG_UPDATES_ARE_ENABLED },
{}
};
enum {
TYPE_REGULAR,
TYPE_PRIVATE, /* -p: Not supported, treated identically to TYPE_REGULAR */
TYPE_EXCLUSIVE, /* -x */
} type = TYPE_REGULAR;
const char *dot, *iface;
int c, r;
assert(argc >= 0);
assert(argv);
/* openresolv checks these environment variables */
if (getenv("IF_EXCLUSIVE"))
type = TYPE_EXCLUSIVE;
if (getenv("IF_PRIVATE"))
type = TYPE_PRIVATE; /* not actually supported */
arg_mode = _MODE_INVALID;
while ((c = getopt_long(argc, argv, "hadxpfm:uIi:l:Rr:vV", options, NULL)) >= 0)
switch(c) {
case 'h':
resolvconf_help();
return 0; /* done */;
case ARG_VERSION:
return version();
/* -a and -d is what everybody can agree on */
case 'a':
arg_mode = MODE_SET_LINK;
break;
case 'd':
arg_mode = MODE_REVERT_LINK;
break;
/* The exclusive/private/force stuff is an openresolv invention, we support in some skewed way */
case 'x':
type = TYPE_EXCLUSIVE;
break;
case 'p':
type = TYPE_PRIVATE; /* not actually supported */
break;
case 'f':
arg_ifindex_permissive = true;
break;
/* The metrics stuff is an openresolv invention we ignore (and don't really need) */
case 'm':
log_debug("Switch -%c ignored.", c);
break;
/* Everybody else can agree on the existance of -u but we don't support it. */
case 'u':
/* The following options are openresolv inventions we don't support. */
case 'I':
case 'i':
case 'l':
case 'R':
case 'r':
case 'v':
case 'V':
log_error("Switch -%c not supported.", c);
return -EINVAL;
/* The Debian resolvconf commands we don't support. */
case ARG_ENABLE_UPDATES:
log_error("Switch --enable-updates not supported.");
return -EINVAL;
case ARG_DISABLE_UPDATES:
log_error("Switch --disable-updates not supported.");
return -EINVAL;
case ARG_UPDATES_ARE_ENABLED:
log_error("Switch --updates-are-enabled not supported.");
return -EINVAL;
case '?':
return -EINVAL;
default:
assert_not_reached("Unhandled option");
}
if (arg_mode == _MODE_INVALID) {
log_error("Expected either -a or -d on the command line.");
return -EINVAL;
}
if (optind+1 != argc) {
log_error("Expected interface name as argument.");
return -EINVAL;
}
dot = strchr(argv[optind], '.');
if (dot) {
iface = strndupa(argv[optind], dot - argv[optind]);
log_debug("Ignoring protocol specifier '%s'.", dot + 1);
} else
iface = argv[optind];
optind++;
if (parse_ifindex(iface, &arg_ifindex) < 0) {
int ifi;
ifi = if_nametoindex(iface);
if (ifi <= 0) {
if (errno == ENODEV && arg_ifindex_permissive) {
log_debug("Interface '%s' not found, but -f specified, ignoring.", iface);
return 0; /* done */
}
return log_error_errno(errno, "Unknown interface '%s': %m", iface);
}
arg_ifindex = ifi;
}
if (arg_mode == MODE_SET_LINK) {
unsigned n = 0;
for (;;) {
_cleanup_free_ char *line = NULL;
const char *a, *l;
r = read_line(stdin, LONG_LINE_MAX, &line);
if (r < 0)
return log_error_errno(r, "Failed to read from stdin: %m");
if (r == 0)
break;
n++;
l = strstrip(line);
if (IN_SET(*l, '#', ';', 0))
continue;
a = first_word(l, "nameserver");
if (a) {
(void) parse_nameserver(a);
continue;
}
a = first_word(l, "domain");
if (!a)
a = first_word(l, "search");
if (a) {
(void) parse_search_domain(a);
continue;
}
log_syntax(NULL, LOG_DEBUG, "stdin", n, 0, "Ignoring resolv.conf line: %s", l);
}
if (type == TYPE_EXCLUSIVE) {
/* If -x mode is selected, let's preferably route non-suffixed lookups to this interface. This
* somewhat matches the original -x behaviour */
r = strv_extend(&arg_set_domain, "~.");
if (r < 0)
return log_oom();
} else if (type == TYPE_PRIVATE)
log_debug("Private DNS server data not supported, ignoring.");
if (arg_n_set_dns == 0) {
log_error("No DNS servers specified, refusing operation.");
return -EINVAL;
}
}
return 1; /* work to do */
}

3
src/resolve/resolvconf-compat.h Normal file
View File

@ -0,0 +1,3 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
int resolvconf_parse_argv(int argc, char *argv[]);

53
src/resolve/resolve-tool.c
View File

@ -36,18 +36,21 @@
#include "netlink-util.h"
#include "pager.h"
#include "parse-util.h"
#include "resolvconf-compat.h"
#include "resolve-tool.h"
#include "resolved-def.h"
#include "resolved-dns-packet.h"
#include "strv.h"
#include "terminal-util.h"
static int arg_family = AF_UNSPEC;
static int arg_ifindex = 0;
int arg_ifindex = 0;
static uint16_t arg_type = 0;
static uint16_t arg_class = 0;
static bool arg_legend = true;
static uint64_t arg_flags = 0;
static bool arg_no_pager = false;
bool arg_ifindex_permissive = false; /* If true, don't generate an error if the specified interface index doesn't exist */
typedef enum ServiceFamily {
SERVICE_FAMILY_TCP,
@ -64,24 +67,11 @@ typedef enum RawType {
} RawType;
static RawType arg_raw = RAW_NONE;
static enum {
MODE_RESOLVE_HOST,
MODE_RESOLVE_RECORD,
MODE_RESOLVE_SERVICE,
MODE_RESOLVE_OPENPGP,
MODE_RESOLVE_TLSA,
MODE_STATISTICS,
MODE_RESET_STATISTICS,
MODE_FLUSH_CACHES,
MODE_RESET_SERVER_FEATURES,
MODE_STATUS,
MODE_SET_LINK,
MODE_REVERT_LINK,
} arg_mode = MODE_RESOLVE_HOST;
ExecutionMode arg_mode = MODE_RESOLVE_HOST;
static struct in_addr_data *arg_set_dns = NULL;
static size_t arg_n_set_dns = 0;
static char **arg_set_domain = NULL;
struct in_addr_data *arg_set_dns = NULL;
size_t arg_n_set_dns = 0;
char **arg_set_domain = NULL;
static char *arg_set_llmnr = NULL;
static char *arg_set_mdns = NULL;
static char *arg_set_dnssec = NULL;
@ -1609,6 +1599,9 @@ static int set_link(sd_bus *bus) {
if (q < 0) {
if (sd_bus_error_has_name(&error, BUS_ERROR_LINK_BUSY))
goto is_managed;
if (arg_ifindex_permissive &&
sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_LINK))
return 0;
log_error_errno(q, "Failed to set DNS configuration: %s", bus_error_message(&error, q));
if (r == 0)
@ -1655,6 +1648,9 @@ static int set_link(sd_bus *bus) {
if (q < 0) {
if (sd_bus_error_has_name(&error, BUS_ERROR_LINK_BUSY))
goto is_managed;
if (arg_ifindex_permissive &&
sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_LINK))
return 0;
log_error_errno(q, "Failed to set domain configuration: %s", bus_error_message(&error, q));
if (r == 0)
@ -1777,8 +1773,13 @@ static int revert_link(sd_bus *bus) {
&error,
NULL,
"i", arg_ifindex);
if (r < 0)
if (r < 0) {
if (arg_ifindex_permissive &&
sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_LINK))
return 0;
return log_error_errno(r, "Failed to revert interface configuration: %s", bus_error_message(&error, r));
}
return 0;
}
@ -1815,7 +1816,7 @@ static void help_dns_classes(void) {
}
}
static void help(void) {
static void native_help(void) {
printf("%1$s [OPTIONS...] HOSTNAME|ADDRESS...\n"
"%1$s [OPTIONS...] --service [[NAME] TYPE] DOMAIN\n"
"%1$s [OPTIONS...] --openpgp EMAIL@DOMAIN...\n"
@ -1858,7 +1859,7 @@ static void help(void) {
, program_invocation_short_name);
}
static int parse_argv(int argc, char *argv[]) {
static int native_parse_argv(int argc, char *argv[]) {
enum {
ARG_VERSION = 0x100,
ARG_LEGEND,
@ -1926,7 +1927,7 @@ static int parse_argv(int argc, char *argv[]) {
switch(c) {
case 'h':
help();
native_help();
return 0; /* done */;
case ARG_VERSION:
@ -2234,7 +2235,10 @@ int main(int argc, char **argv) {
log_parse_environment();
log_open();
r = parse_argv(argc, argv);
if (streq(program_invocation_short_name, "resolvconf"))
r = resolvconf_parse_argv(argc, argv);
else
r = native_parse_argv(argc, argv);
if (r <= 0)
goto finish;
@ -2435,6 +2439,9 @@ int main(int argc, char **argv) {
r = revert_link(bus);
break;
case _MODE_INVALID:
assert_not_reached("invalid mode");
}
finish:

30
src/resolve/resolve-tool.h Normal file
View File

@ -0,0 +1,30 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <in-addr-util.h>
#include <stdbool.h>
#include <sys/types.h>
extern int arg_ifindex;
extern bool arg_ifindex_permissive;
typedef enum ExecutionMode {
MODE_RESOLVE_HOST,
MODE_RESOLVE_RECORD,
MODE_RESOLVE_SERVICE,
MODE_RESOLVE_OPENPGP,
MODE_RESOLVE_TLSA,
MODE_STATISTICS,
MODE_RESET_STATISTICS,
MODE_FLUSH_CACHES,
MODE_RESET_SERVER_FEATURES,
MODE_STATUS,
MODE_SET_LINK,
MODE_REVERT_LINK,
_MODE_INVALID = -1,
} ExecutionMode;
extern ExecutionMode arg_mode;
extern struct in_addr_data *arg_set_dns;
extern size_t arg_n_set_dns;
extern char **arg_set_domain;

3
src/resolve/resolved-def.h
View File

@ -41,3 +41,6 @@
#define SD_RESOLVED_PROTOCOLS_ALL (SD_RESOLVED_MDNS|SD_RESOLVED_LLMNR|SD_RESOLVED_DNS)
#define SD_RESOLVED_QUERY_TIMEOUT_USEC (120 * USEC_PER_SEC)
/* 127.0.0.53 in native endian */
#define INADDR_DNS_STUB ((in_addr_t) 0x7f000035U)

3
src/resolve/resolved-dns-stub.h
View File

@ -22,8 +22,5 @@
#include "resolved-manager.h"
/* 127.0.0.53 in native endian */
#define INADDR_DNS_STUB ((in_addr_t) 0x7f000035U)
void manager_dns_stub_stop(Manager *m);
int manager_dns_stub_start(Manager *m);