@@ -477,7 +477,7 @@ SOCKET_INCLUDES="
"
AC_CHECK_HEADERS(
- [net/if.h netinet/ip.h resolv.h sys/un.h net/if_utun.h sys/kern_control.h],
+ [net/if.h netinet/ip.h arpa/nameser.h resolv.h sys/un.h net/if_utun.h sys/kern_control.h],
,
,
[[${SOCKET_INCLUDES}]]
@@ -299,10 +299,88 @@ configuration.
specification (4/6 suffix), OpenVPN will try both IPv4 and IPv6
addresses, in the order getaddrinfo() returns them.
+--remote-srv args
+ Perform DNS SRV remote host discovery using specified ``domain`` and
+ two additional optional arguments: ``service`` and ``proto``. On the
+ client, multiple ``--remote-srv`` options may be specified for
+ redundancy, each referring to a different DNS SRV domain. Specifying
+ multiple ``--remote`` or ``--remote-srv`` options for this purpose is
+ a special case of the more general connection-profile feature. See the
+ ``<connection>`` documentation below.
+
+ Client will try to resolve ``_service._proto.domain`` name via DNS and
+ use returned DNS SRV records as OpenVPN remote server list ordered by
+ server selection mechanism defined in RFC 2782:
+ ::
+
+ A client MUST attempt to contact the target host with the
+ lowest-numbered priority field value it can reach, target hosts
+ with the same priority SHOULD be tried in an order defined by the
+ weight field.
+ The weight field specifies a relative weight for entries with the
+ same priority. Larger weights SHOULD be given a proportionately
+ higher probability of being selected.
+ Domain administrators SHOULD use Weight 0 when there isn't any
+ server selection to do. In the presence of records containing
+ weights greater than 0, records with weight 0 SHOULD have a very
+ small chance of being selected.
+
+ If one DNS SRV record resolves to multiple IP addresses, OpenVPN will
+ try them in the order that the system getaddrinfo() presents them.
+
+ Example:
+ ::
+
+ remote-srv example.net
+ remote-srv example.net openvpn
+ remote-srv example.net openvpn auto
+
+ By default, ``service`` is :code:`openvpn` as OpenVPN's IANA registered
+ service name.
+
+ ``proto`` indicates the protocol part for discovery and the protocol to
+ use when connecting with the remote. It may be :code:`tcp`, :code:`udp`
+ or special value :code:`auto` used by default to try both. In this case
+ all the discovered remote servers will be ordered by server selection
+ mechanism regardless the used protocol.
+
+ For forcing IPv4 or IPv6 connection suffix tcp, udp or auto with 4/6 like
+ udp4/udp6/tcp4/tcp6/auto4/auto6.
+
+ DNS SRV records example:
+ ::
+
+ name prio weight port target
+ _openvpn._udp.example.net IN SRV 10 60 1194 s1.example.net
+ _openvpn._udp.example.net IN SRV 10 40 1194 s2.example.net
+ _openvpn._udp.example.net IN SRV 10 0 1194 s3.example.net
+ _openvpn._tcp.example.net IN SRV 20 0 443 s4.example.net
+
+ For above, client will first try to resolve ``_openvpn._udp.example.net``
+ and ``_openvpn._tcp.example.net`` names.
+ Next, ``s1.example.net``, ``s2.example.net`` and ``s3.example.net`` will
+ be ordered before ``s4.example.net`` as their priority 10 is smaller
+ than 20.
+ Next, ``s1.example.net``, ``s2.example.net`` and ``s3.example.net`` will
+ be randomly ordered with weight probability - first will be either
+ ``s1.example.net`` with probability 60% or ``s2.example.net`` with 40%
+ or ``s3.example.net`` with almost zero probability.
+ Next, if ``s1.example.net`` is picked as first, second server will be
+ either ``s2.example.net`` with almost 100% probability or
+ ``s3.example.net`` instead.
+ Next, if ``s2.example.net`` is picked as second, ``s3.example.net`` will
+ be skipped due zero weight.
+ ``s4.example.net`` will be the last one as the only server with prio 20.
+ Finally, servers will be resolved and accessed in this order.
+
+ If ``_openvpn._udp.example.net`` and ``_openvpn._udp.example.net`` can't
+ be resolved or no valid records were returned, client will move on to the
+ next connection entry.
+
--remote-random
- When multiple ``--remote`` address/ports are specified, or if connection
- profiles are being used, initially randomize the order of the list as a
- kind of basic load-balancing measure.
+ When multiple ``--remote`` address/ports or ``--remote-srv`` records are
+ specified, or if connection profiles are being used, initially randomize
+ the order of the list as a kind of basic load-balancing measure.
--remote-random-hostname
Prepend a random string (6 bytes, 12 hex characters) to hostname to
@@ -310,8 +388,8 @@ configuration.
"<random-chars>.foo.bar.gov".
--resolv-retry n
- If hostname resolve fails for ``--remote``, retry resolve for ``n``
- seconds before failing.
+ If hostname resolve fails for ``--remote`` or ``--remote-srv``, retry
+ resolve for ``n`` seconds before failing.
Set ``n`` to "infinite" to retry indefinitely.
@@ -851,6 +851,12 @@ the above notification, use this command:
remote MOD vpn.otherexample.com 1234
+DNS SRV discovery domain and service name with protocol code:`auto`
+can't be overriden, but either acceted or skipped only.
+Example of such notification:
+
+ >REMOTE:example.com,openvpn,auto
+
To accept the same host and port as the client would ordinarily
have connected to, use this command:
@@ -143,5 +143,5 @@ openvpn_LDADD = \
$(OPTIONAL_INOTIFY_LIBS)
if WIN32
openvpn_SOURCES += openvpn_win32_resources.rc block_dns.c block_dns.h ring_buffer.h
-openvpn_LDADD += -lgdi32 -lws2_32 -lwininet -lcrypt32 -liphlpapi -lwinmm -lfwpuclnt -lrpcrt4 -lncrypt -lsetupapi
+openvpn_LDADD += -lgdi32 -lws2_32 -lwininet -lcrypt32 -liphlpapi -lwinmm -lfwpuclnt -lrpcrt4 -lncrypt -lsetupapi -ldnsapi
endif
@@ -198,11 +198,6 @@ bool buf_init_debug(struct buffer *buf, int offset, const char *file, int line);
/* inline functions */
-inline static void
-gc_freeaddrinfo_callback(void *addr)
-{
- freeaddrinfo((struct addrinfo *) addr);
-}
/** Return an empty struct buffer */
static inline struct buffer
@@ -91,6 +91,7 @@
#define D_OSBUF LOGLEV(3, 43, 0) /* show socket/tun/tap buffer sizes */
#define D_PS_PROXY LOGLEV(3, 44, 0) /* messages related to --port-share option */
#define D_PF_INFO LOGLEV(3, 45, 0) /* packet filter informational messages */
+#define D_RESOLVE_INFO LOGLEV(3, 46, 0) /* show hostname resolve info */
#define D_SHOW_PARMS LOGLEV(4, 50, 0) /* show all parameters on program initiation */
#define D_SHOW_OCC LOGLEV(4, 51, 0) /* show options compatibility string */
@@ -352,7 +352,12 @@ management_callback_remote_cmd(void *arg, const char **p)
}
else if (!strcmp(p[1], "MOD") && p[2] && p[3])
{
- if (strlen(p[2]) < RH_HOST_LEN && strlen(p[3]) < RH_PORT_LEN)
+ if (ce->remote_srv && ce->proto == PROTO_AUTO)
+ {
+ /* can't mutate --remote-srv into --remote without protocol */
+ ret = false;
+ }
+ else if (strlen(p[2]) < RH_HOST_LEN && strlen(p[3]) < RH_PORT_LEN)
{
struct remote_host_store *rhs = c->options.rh_store;
if (!rhs)
@@ -365,6 +370,7 @@ management_callback_remote_cmd(void *arg, const char **p)
ce->remote = rhs->host;
ce->remote_port = rhs->port;
+ ce->remote_srv = false;
flags = CE_MAN_QUERY_REMOTE_MOD;
ret = true;
}
@@ -456,10 +462,16 @@ init_connection_list(struct context *c)
static void
clear_remote_addrlist(struct link_socket_addr *lsa, bool free)
{
- if (lsa->remote_list && free)
+ if (lsa->service_list && free)
+ {
+ freeservinfo(lsa->service_list);
+ }
+ else if (lsa->remote_list && free)
{
freeaddrinfo(lsa->remote_list);
}
+ lsa->service_list = NULL;
+ lsa->current_service = NULL;
lsa->remote_list = NULL;
lsa->current_remote = NULL;
}
@@ -492,8 +504,29 @@ next_connection_entry(struct context *c)
c->c1.link_socket_addr.current_remote =
c->c1.link_socket_addr.current_remote->ai_next;
}
+ /* Check if there is another resolved service to try for
+ * the current connection */
+ else if (c->c1.link_socket_addr.current_service
+ && c->c1.link_socket_addr.current_service->next)
+ {
+ c->c1.link_socket_addr.current_service =
+ c->c1.link_socket_addr.current_service->next;
+ c->c1.link_socket_addr.remote_list =
+ c->c1.link_socket_addr.current_service->ai;
+ c->c1.link_socket_addr.current_remote =
+ c->c1.link_socket_addr.remote_list;
+ }
else
{
+ /* All services iterated w/o close_instance, so clear
+ * the addrinfo objects here */
+ if (c->c1.link_socket_addr.service_list)
+ {
+ ASSERT(!c->options.persist_remote_ip);
+ clear_remote_addrlist(&c->c1.link_socket_addr,
+ !c->options.resolve_in_advance);
+ }
+
/* FIXME (schwabe) fix the persist-remote-ip option for real,
* this is broken probably ever since connection lists and multiple
* remote existed
@@ -538,8 +571,14 @@ next_connection_entry(struct context *c)
}
c->options.ce = *ce;
+ if (ce_defined && c->c1.link_socket_addr.current_service)
+ {
+ /* map in current service */
+ struct servinfo *si = c->c1.link_socket_addr.current_service;
+ ce_defined = options_mutate_ce_servinfo(&c->options, si);
+ }
#ifdef ENABLE_MANAGEMENT
- if (ce_defined && management && management_query_remote_enabled(management))
+ else if (ce_defined && management && management_query_remote_enabled(management))
{
/* allow management interface to override connection entry details */
ce_defined = ce_management_query_remote(c);
@@ -3636,6 +3675,7 @@ do_close_link_socket(struct context *c)
||
( c->sig->source != SIG_SOURCE_HARD
&& ((c->c1.link_socket_addr.current_remote && c->c1.link_socket_addr.current_remote->ai_next)
+ || (c->c1.link_socket_addr.current_service && c->c1.link_socket_addr.current_service->next)
|| c->options.no_advance))
)))
{
@@ -4171,6 +4211,17 @@ init_instance(struct context *c, const struct env_set *env, const unsigned int f
/* map in current connection entry */
next_connection_entry(c);
+ /* map in current remote service */
+ if (c->options.ce.remote_srv)
+ {
+ do_resolve_service(c);
+ if (IS_SIG(c))
+ {
+ goto sig;
+ }
+ update_options_ce_post(&c->options);
+ }
+
/* link_socket_mode allows CM_CHILD_TCP
* instances to inherit acceptable fds
* from a top-level parent */
@@ -92,7 +92,7 @@
</ClCompile>
<ResourceCompile />
<Link>
- <AdditionalDependencies>legacy_stdio_definitions.lib;Ncrypt.lib;libssl.lib;libcrypto.lib;lzo2.lib;pkcs11-helper.dll.lib;gdi32.lib;ws2_32.lib;wininet.lib;crypt32.lib;iphlpapi.lib;winmm.lib;Fwpuclnt.lib;Rpcrt4.lib;%(AdditionalDependencies)</AdditionalDependencies>
+ <AdditionalDependencies>legacy_stdio_definitions.lib;Ncrypt.lib;libssl.lib;libcrypto.lib;lzo2.lib;pkcs11-helper.dll.lib;gdi32.lib;ws2_32.lib;wininet.lib;crypt32.lib;iphlpapi.lib;winmm.lib;Fwpuclnt.lib;Rpcrt4.lib;dnsapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
<AdditionalLibraryDirectories>$(OPENSSL_HOME)/lib;$(LZO_HOME)/lib;$(PKCS11H_HOME)/lib;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
<SubSystem>Console</SubSystem>
</Link>
@@ -107,7 +107,7 @@
</ClCompile>
<ResourceCompile />
<Link>
- <AdditionalDependencies>legacy_stdio_definitions.lib;Ncrypt.lib;libssl.lib;libcrypto.lib;lzo2.lib;pkcs11-helper.dll.lib;gdi32.lib;ws2_32.lib;wininet.lib;crypt32.lib;iphlpapi.lib;winmm.lib;Fwpuclnt.lib;Rpcrt4.lib;setupapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
+ <AdditionalDependencies>legacy_stdio_definitions.lib;Ncrypt.lib;libssl.lib;libcrypto.lib;lzo2.lib;pkcs11-helper.dll.lib;gdi32.lib;ws2_32.lib;wininet.lib;crypt32.lib;iphlpapi.lib;winmm.lib;Fwpuclnt.lib;Rpcrt4.lib;setupapi.lib;dnsapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
<AdditionalLibraryDirectories>$(OPENSSL_HOME)/lib;$(LZO_HOME)/lib;$(PKCS11H_HOME)/lib;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
<SubSystem>Console</SubSystem>
</Link>
@@ -122,7 +122,7 @@
</ClCompile>
<ResourceCompile />
<Link>
- <AdditionalDependencies>legacy_stdio_definitions.lib;Ncrypt.lib;libssl.lib;libcrypto.lib;lzo2.lib;pkcs11-helper.dll.lib;gdi32.lib;ws2_32.lib;wininet.lib;crypt32.lib;iphlpapi.lib;winmm.lib;Fwpuclnt.lib;Rpcrt4.lib;%(AdditionalDependencies)</AdditionalDependencies>
+ <AdditionalDependencies>legacy_stdio_definitions.lib;Ncrypt.lib;libssl.lib;libcrypto.lib;lzo2.lib;pkcs11-helper.dll.lib;gdi32.lib;ws2_32.lib;wininet.lib;crypt32.lib;iphlpapi.lib;winmm.lib;Fwpuclnt.lib;Rpcrt4.lib;dnsapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
<AdditionalLibraryDirectories>$(OPENSSL_HOME)/lib;$(LZO_HOME)/lib;$(PKCS11H_HOME)/lib;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
<SubSystem>Console</SubSystem>
</Link>
@@ -137,7 +137,7 @@
</ClCompile>
<ResourceCompile />
<Link>
- <AdditionalDependencies>legacy_stdio_definitions.lib;Ncrypt.lib;libssl.lib;libcrypto.lib;lzo2.lib;pkcs11-helper.dll.lib;gdi32.lib;ws2_32.lib;wininet.lib;crypt32.lib;iphlpapi.lib;winmm.lib;Fwpuclnt.lib;Rpcrt4.lib;setupapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
+ <AdditionalDependencies>legacy_stdio_definitions.lib;Ncrypt.lib;libssl.lib;libcrypto.lib;lzo2.lib;pkcs11-helper.dll.lib;gdi32.lib;ws2_32.lib;wininet.lib;crypt32.lib;iphlpapi.lib;winmm.lib;Fwpuclnt.lib;Rpcrt4.lib;setupapi.lib;dnsapi.lib;%(AdditionalDependencies)</AdditionalDependencies>
<AdditionalLibraryDirectories>$(OPENSSL_HOME)/lib;$(LZO_HOME)/lib;$(PKCS11H_HOME)/lib;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
<SubSystem>Console</SubSystem>
</Link>
@@ -121,6 +121,7 @@ static const char usage_message[] =
"Tunnel Options:\n"
"--local host : Local host name or ip address. Implies --bind.\n"
"--remote host [port] : Remote host name or ip address.\n"
+ "--remote-srv domain [service] : Perform DNS SRV remote host discovery.\n"
"--remote-random : If multiple --remote options specified, choose one randomly.\n"
"--remote-random-hostname : Add a random string to remote DNS name.\n"
"--mode m : Major mode, m = 'p2p' (default, point-to-point) or 'server'.\n"
@@ -1446,6 +1447,7 @@ show_connection_entry(const struct connection_entry *o)
SHOW_STR(local_port);
SHOW_STR(remote);
SHOW_STR(remote_port);
+ SHOW_BOOL(remote_srv);
SHOW_BOOL(remote_float);
SHOW_BOOL(bind_defined);
SHOW_BOOL(bind_local);
@@ -1980,6 +1982,58 @@ connection_entry_load_re(struct connection_entry *ce, const struct remote_entry
{
ce->af = re->af;
}
+ ce->remote_srv = re->remote_srv;
+}
+
+static bool
+options_postprocess_verify_ce_proto(const struct options *options, const struct connection_entry *ce)
+{
+ int level = M_WARN|M_NOPREFIX|M_OPTERR;
+
+ /*
+ * Sanity check on --local, --remote, and --ifconfig
+ */
+
+ if (proto_is_net(ce->proto)
+ && string_defined_equal(ce->local, ce->remote)
+ && string_defined_equal(ce->local_port, ce->remote_port))
+ {
+ msg(level, "--remote and --local addresses are the same");
+ return false;
+ }
+
+ if (string_defined_equal(ce->remote, options->ifconfig_local)
+ || string_defined_equal(ce->remote, options->ifconfig_remote_netmask))
+ {
+ msg(level, "--local and --remote addresses must be distinct from --ifconfig addresses");
+ return false;
+ }
+
+ /*
+ * Check that protocol options make sense.
+ */
+
+#ifdef ENABLE_FRAGMENT
+ if (!proto_is_udp(ce->proto) && ce->fragment)
+ {
+ msg(level, "--fragment can only be used with --proto udp");
+ return false;
+ }
+#endif
+
+ if (!proto_is_udp(ce->proto) && ce->explicit_exit_notification)
+ {
+ msg(level, "--explicit-exit-notify can only be used with --proto udp");
+ return false;
+ }
+
+ if ((ce->http_proxy_options) && ce->proto != PROTO_TCP_CLIENT)
+ {
+ msg(level, "--http-proxy MUST be used in TCP Client mode (i.e. --proto tcp-client)");
+ return false;
+ }
+
+ return true;
}
static void
@@ -2014,6 +2068,11 @@ options_postprocess_verify_ce(const struct options *options, const struct connec
msg(M_USAGE, "--proto tcp is ambiguous in this context. Please specify --proto tcp-server or --proto tcp-client");
}
+ if (ce->proto == PROTO_AUTO && !ce->remote_srv)
+ {
+ msg(M_USAGE, "--proto auto can be only used with --remote-srv");
+ }
+
/*
* Sanity check on daemon/inetd modes
*/
@@ -2023,9 +2082,9 @@ options_postprocess_verify_ce(const struct options *options, const struct connec
msg(M_USAGE, "only one of --daemon or --inetd may be specified");
}
- if (options->inetd && (ce->local || ce->remote))
+ if (options->inetd && (ce->local || ce->remote || ce->remote_srv))
{
- msg(M_USAGE, "--local or --remote cannot be used with --inetd");
+ msg(M_USAGE, "--local or --remote or --remote_srv cannot be used with --inetd");
}
if (options->inetd && ce->proto == PROTO_TCP_CLIENT)
@@ -2070,7 +2129,8 @@ options_postprocess_verify_ce(const struct options *options, const struct connec
if (!proto_is_udp(ce->proto) && options->mtu_test)
{
- msg(M_USAGE, "--mtu-test only makes sense with --proto udp");
+ int level = (ce->proto == PROTO_AUTO) ? M_WARN|M_NOPREFIX|M_OPTERR : M_USAGE;
+ msg(level, "--mtu-test only makes sense with --proto udp");
}
/* will we be pulling options from server? */
@@ -2082,6 +2142,11 @@ options_postprocess_verify_ce(const struct options *options, const struct connec
* Sanity check on --local, --remote, and --ifconfig
*/
+ if (ce->remote_srv && options->ip_remote_hint)
+ {
+ msg(M_USAGE, "--remote-srv and --ip_remote_hint can't be used together");
+ }
+
if (proto_is_net(ce->proto)
&& string_defined_equal(ce->local, ce->remote)
&& string_defined_equal(ce->local_port, ce->remote_port))
@@ -2200,13 +2265,15 @@ options_postprocess_verify_ce(const struct options *options, const struct connec
#ifdef ENABLE_FRAGMENT
if (!proto_is_udp(ce->proto) && ce->fragment)
{
- msg(M_USAGE, "--fragment can only be used with --proto udp");
+ int level = (ce->proto == PROTO_AUTO) ? M_WARN|M_NOPREFIX|M_OPTERR : M_USAGE;
+ msg(level, "--fragment can only be used with --proto udp");
}
#endif
if (!proto_is_udp(ce->proto) && ce->explicit_exit_notification)
{
- msg(M_USAGE, "--explicit-exit-notify can only be used with --proto udp");
+ int level = (ce->proto == PROTO_AUTO) ? M_WARN|M_NOPREFIX|M_OPTERR : M_USAGE;
+ msg(level, "--explicit-exit-notify can only be used with --proto udp");
}
if (!ce->remote && ce->proto == PROTO_TCP_CLIENT)
@@ -2216,8 +2283,10 @@ options_postprocess_verify_ce(const struct options *options, const struct connec
if ((ce->http_proxy_options) && ce->proto != PROTO_TCP_CLIENT)
{
- msg(M_USAGE, "--http-proxy MUST be used in TCP Client mode (i.e. --proto tcp-client)");
+ int level = (ce->proto == PROTO_AUTO) ? M_WARN|M_NOPREFIX|M_OPTERR : M_USAGE;
+ msg(level, "--http-proxy MUST be used in TCP Client mode (i.e. --proto tcp-client)");
}
+
if ((ce->http_proxy_options) && !ce->http_proxy_options->server)
{
msg(M_USAGE, "--http-proxy not specified but other http proxy options present");
@@ -2279,6 +2348,10 @@ options_postprocess_verify_ce(const struct options *options, const struct connec
{
msg(M_USAGE, "--remote cannot be used with --mode server");
}
+ if (ce->remote_srv)
+ {
+ msg(M_USAGE, "--remote-srv cannot be used with --mode server");
+ }
if (!ce->bind_local)
{
msg(M_USAGE, "--nobind cannot be used with --mode server");
@@ -2793,6 +2866,53 @@ options_postprocess_verify_ce(const struct options *options, const struct connec
uninit_options(&defaults);
}
+static bool
+options_postprocess_mutate_ce_proto(struct options *o, struct connection_entry *ce)
+{
+ bool result = true;
+
+ if (ce->proto == PROTO_TCP_CLIENT && !ce->local && !ce->local_port_defined && !ce->bind_defined)
+ {
+ ce->bind_local = false;
+ }
+
+ if (ce->proto == PROTO_UDP && ce->socks_proxy_server && !ce->local && !ce->local_port_defined && !ce->bind_defined)
+ {
+ ce->bind_local = false;
+ }
+
+ if (!ce->bind_local)
+ {
+ ce->local_port = NULL;
+ }
+
+ /* if protocol forcing is enabled, disable all protocols except for the forced one */
+ if (o->proto_force >= 0 && o->proto_force != ce->proto && ce->proto != PROTO_AUTO)
+ {
+ result = false;
+ }
+
+ /* our socks code is not fully IPv6 enabled yet (TCP works, UDP not)
+ * so fall back to IPv4-only (trac #1221)
+ */
+ if (ce->socks_proxy_server && proto_is_udp(ce->proto) && ce->af != AF_INET)
+ {
+ if (ce->af == AF_INET6)
+ {
+ msg(M_INFO, "WARNING: '--proto udp6' is not compatible with "
+ "'--socks-proxy' today. Forcing IPv4 mode." );
+ }
+ else
+ {
+ msg(M_INFO, "NOTICE: dual-stack mode for '--proto udp' does not "
+ "work correctly with '--socks-proxy' today. Forcing IPv4." );
+ }
+ ce->af = AF_INET;
+ }
+
+ return result;
+}
+
static void
options_postprocess_mutate_ce(struct options *o, struct connection_entry *ce)
{
@@ -2816,23 +2936,7 @@ options_postprocess_mutate_ce(struct options *o, struct connection_entry *ce)
}
#endif
- if (ce->proto == PROTO_TCP_CLIENT && !ce->local && !ce->local_port_defined && !ce->bind_defined)
- {
- ce->bind_local = false;
- }
-
- if (ce->proto == PROTO_UDP && ce->socks_proxy_server && !ce->local && !ce->local_port_defined && !ce->bind_defined)
- {
- ce->bind_local = false;
- }
-
- if (!ce->bind_local)
- {
- ce->local_port = NULL;
- }
-
- /* if protocol forcing is enabled, disable all protocols except for the forced one */
- if (o->proto_force >= 0 && o->proto_force != ce->proto)
+ if (!options_postprocess_mutate_ce_proto(o, ce))
{
ce->flags |= CE_DISABLED;
}
@@ -2853,24 +2957,6 @@ options_postprocess_mutate_ce(struct options *o, struct connection_entry *ce)
#endif
}
- /* our socks code is not fully IPv6 enabled yet (TCP works, UDP not)
- * so fall back to IPv4-only (trac #1221)
- */
- if (ce->socks_proxy_server && proto_is_udp(ce->proto) && ce->af != AF_INET)
- {
- if (ce->af == AF_INET6)
- {
- msg(M_INFO, "WARNING: '--proto udp6' is not compatible with "
- "'--socks-proxy' today. Forcing IPv4 mode." );
- }
- else
- {
- msg(M_INFO, "NOTICE: dual-stack mode for '--proto udp' does not "
- "work correctly with '--socks-proxy' today. Forcing IPv4." );
- }
- ce->af = AF_INET;
- }
-
/*
* Set MTU defaults
*/
@@ -2938,6 +3024,32 @@ options_postprocess_mutate_ce(struct options *o, struct connection_entry *ce)
}
}
+/*
+ * Merges servinfo's hostname, servname and proto into current connection
+ * entry if possible and doesn't conflict with the options.
+ * Used by runtime DNS SRV discovery.
+ */
+bool
+options_mutate_ce_servinfo(struct options *o, struct servinfo *si)
+{
+ struct connection_entry ce = o->ce;
+
+ ASSERT(ce.remote_srv);
+
+ ce.remote = si->hostname;
+ ce.remote_port = si->servname;
+ ce.proto = si->proto;
+
+ if (options_postprocess_mutate_ce_proto(o, &ce)
+ && options_postprocess_verify_ce_proto(o, &ce))
+ {
+ o->ce = ce;
+ return true;
+ }
+
+ return false;
+}
+
#ifdef _WIN32
/* If iservice is in use, we need def1 method for redirect-gateway */
static void
@@ -5675,6 +5787,7 @@ add_option(struct options *options,
{
struct remote_entry re;
re.remote = re.remote_port = NULL;
+ re.remote_srv = false;
re.proto = -1;
re.af = 0;
@@ -5710,6 +5823,47 @@ add_option(struct options *options,
connection_entry_load_re(&options->ce, &re);
}
}
+ else if (streq(p[0], "remote-srv") && p[1] && !p[4])
+ {
+ struct remote_entry re;
+ re.remote = NULL;
+ re.remote_port = OPENVPN_SERVICE;
+ re.remote_srv = true;
+ re.proto = PROTO_AUTO;
+ re.af = 0;
+
+ VERIFY_PERMISSION(OPT_P_GENERAL|OPT_P_CONNECTION);
+ re.remote = p[1];
+ if (p[2])
+ {
+ re.remote_port = p[2];
+ if (p[3])
+ {
+ const int proto = ascii2proto(p[3]);
+ const sa_family_t af = ascii2af(p[3]);
+ if (proto < 0)
+ {
+ msg(msglevel, "remote-srv: bad protocol associated with host %s: '%s'", p[1], p[3]);
+ goto err;
+ }
+ re.proto = proto;
+ re.af = af;
+ }
+ }
+ if (permission_mask & OPT_P_GENERAL)
+ {
+ struct remote_entry *e = alloc_remote_entry(options, msglevel);
+ if (!e)
+ {
+ goto err;
+ }
+ *e = re;
+ }
+ else if (permission_mask & OPT_P_CONNECTION)
+ {
+ connection_entry_load_re(&options->ce, &re);
+ }
+ }
else if (streq(p[0], "resolv-retry") && p[1] && !p[2])
{
VERIFY_PERMISSION(OPT_P_GENERAL);
@@ -6222,7 +6376,7 @@ add_option(struct options *options,
int proto_force;
VERIFY_PERMISSION(OPT_P_GENERAL);
proto_force = ascii2proto(p[1]);
- if (proto_force < 0)
+ if (proto_force < 0 || proto_force == PROTO_AUTO)
{
msg(msglevel, "Bad --proto-force protocol: '%s'", p[1]);
goto err;
@@ -92,6 +92,7 @@ struct connection_entry
const char *remote_port;
const char *local;
const char *remote;
+ bool remote_srv;
bool remote_float;
bool bind_defined;
bool bind_ipv6_only;
@@ -152,6 +153,7 @@ struct remote_entry
const char *remote_port;
int proto;
sa_family_t af;
+ bool remote_srv;
};
#define CONNECTION_LIST_SIZE 64
@@ -787,6 +789,8 @@ char *options_string_extract_option(const char *options_string,
void options_postprocess(struct options *options);
+bool options_mutate_ce_servinfo(struct options *o, struct servinfo *si);
+
void pre_pull_save(struct options *o);
void pre_pull_restore(struct options *o, struct gc_arena *gc);
@@ -260,22 +260,37 @@ get_cached_dns_entry(struct cached_dns_entry *dns_cache,
const char *servname,
int ai_family,
int resolve_flags,
- struct addrinfo **ai)
+ struct addrinfo **ai,
+ struct servinfo **si)
{
struct cached_dns_entry *ph;
int flags;
/* Only use flags that are relevant for the structure */
- flags = resolve_flags & GETADDR_CACHE_MASK;
+ if (si)
+ {
+ flags = resolve_flags & GETADDR_CACHE_SERVICE_MASK;
+ }
+ else
+ {
+ flags = resolve_flags & GETADDR_CACHE_MASK;
+ }
for (ph = dns_cache; ph; ph = ph->next)
{
if (streqnull(ph->hostname, hostname)
&& streqnull(ph->servname, servname)
- && ph->ai_family == ai_family
+ && (si || ph->ai_family == ai_family)
&& ph->flags == flags)
{
- *ai = ph->ai;
+ if (si)
+ {
+ *si = ph->si;
+ }
+ else if (ai)
+ {
+ *ai = ph->ai;
+ }
return 0;
}
}
@@ -298,7 +313,7 @@ do_preresolve_host(struct context *c,
servname,
af,
flags,
- &ai) == 0)
+ &ai, NULL) == 0)
{
/* entry already cached, return success */
return 0;
@@ -337,6 +352,76 @@ do_preresolve_host(struct context *c,
return status;
}
+static int
+do_preresolve_service(struct context *c,
+ const char *hostname,
+ const char *servname,
+ const int af,
+ const int flags,
+ bool preresolve_host)
+{
+ struct servinfo *si;
+ int status;
+
+ if (get_cached_dns_entry(c->c1.dns_cache,
+ hostname,
+ servname,
+ af,
+ flags,
+ NULL, &si) == 0)
+ {
+ /* entry already cached, return success */
+ return 0;
+ }
+
+ status = openvpn_getservinfo(flags, hostname, servname,
+ c->options.resolve_retry_seconds, NULL,
+ af, &si);
+ if (status == 0)
+ {
+ struct cached_dns_entry *ph;
+
+ ALLOC_OBJ_CLEAR_GC(ph, struct cached_dns_entry, &c->gc);
+ ph->si = si;
+ ph->hostname = hostname;
+ ph->servname = servname;
+ ph->flags = flags & GETADDR_CACHE_SERVICE_MASK;
+
+ if (!c->c1.dns_cache)
+ {
+ c->c1.dns_cache = ph;
+ }
+ else
+ {
+ struct cached_dns_entry *prev = c->c1.dns_cache;
+ while (prev->next)
+ {
+ prev = prev->next;
+ }
+ prev->next = ph;
+ }
+
+ gc_addspecial(si, &gc_freeservinfo_callback, &c->gc);
+
+ /* preresolve service targets unless disabled */
+ if (preresolve_host)
+ {
+ while (si)
+ {
+ int host_flags = flags & ~GETADDR_PROTO_MASK;
+ if (proto_is_dgram(si->proto))
+ {
+ host_flags |= GETADDR_DATAGRAM;
+ }
+ /* ignore errors */
+ do_preresolve_host(c, si->hostname, si->servname, af, host_flags);
+ si = si->next;
+ }
+ }
+ }
+ return status;
+}
+
void
do_preresolve(struct context *c)
{
@@ -375,8 +460,30 @@ do_preresolve(struct context *c)
remote = ce->remote;
}
+ /* Preresolve remote services */
+ if (ce->remote_srv)
+ {
+ int service_flags = flags|GETADDR_SERVICE;
+
+ if (proto_is_dgram(ce->proto) || ce->proto == PROTO_AUTO)
+ {
+ service_flags |= GETADDR_DATAGRAM;
+ }
+ if (proto_is_stream(ce->proto) || ce->proto == PROTO_AUTO)
+ {
+ service_flags |= GETADDR_STREAM;
+ }
+
+ /* HTTP remote hostnames does not need to be resolved */
+ status = do_preresolve_service(c, remote, ce->remote_port, ce->af,
+ service_flags, !ce->http_proxy_options);
+ if (status != 0)
+ {
+ goto err;
+ }
+ }
/* HTTP remote hostname does not need to be resolved */
- if (!ce->http_proxy_options)
+ else if (!ce->http_proxy_options)
{
status = do_preresolve_host(c, remote, ce->remote_port, ce->af, flags);
if (status != 0)
@@ -432,6 +539,584 @@ err:
throw_signal_soft(SIGHUP, "Preresolving failed");
}
+/*
+ * Allocates new service structure on heap and stores
+ * its initial host, port and proto values.
+ */
+static struct servinfo *
+alloc_servinfo(const char *hostname, uint16_t port, int proto)
+{
+ size_t namesize = hostname ? strlen(hostname) + 1 : 0;
+
+ char servname[sizeof("65535")];
+ openvpn_snprintf(servname, sizeof(servname), "%u", port);
+ size_t servsize = strlen(servname) + 1;
+
+ struct servinfo *si = calloc(1, sizeof(*si) + namesize + servsize);
+ if (si)
+ {
+ if (hostname)
+ {
+ si->hostname = (char *)(si + 1);
+ memcpy((char *)si->hostname, hostname, namesize);
+ }
+ si->servname = (char *)(si + 1) + namesize;
+ memcpy((char *)si->servname, servname, servsize);
+ si->proto = proto;
+ }
+ return si;
+}
+
+#ifdef _WIN32
+/*
+ * Queries DNS SRV records for specified DNS domain.
+ * Returns EAI_* status and service list on success in order of receive.
+ */
+static int
+query_servinfo_win32(const char *domain, int proto, struct servinfo *next,
+ struct servinfo **res)
+{
+ PDNS_RECORD pDnsRecord;
+ int status;
+
+ ASSERT(res);
+
+ DNS_STATUS DnsStatus = DnsQuery(domain, DNS_TYPE_SRV, DNS_QUERY_STANDARD, NULL, &pDnsRecord, NULL);
+ dmsg(D_SOCKET_DEBUG, "DNSQUERY type=%d domain=%s result=%d",
+ DNS_TYPE_SRV, domain, DnsStatus);
+ switch (DnsStatus)
+ {
+ case ERROR_SUCCESS:
+ break;
+
+ case DNS_ERROR_RCODE_NAME_ERROR:
+ return EAI_NONAME; /* HOST_NOT_FOUND */
+
+ case DNS_INFO_NO_RECORDS:
+ return EAI_NODATA; /* NO_DATA */
+
+ case DNS_ERROR_NO_DNS_SERVERS:
+ case DNS_ERROR_RCODE_FORMAT_ERROR:
+ case DNS_ERROR_RCODE_NOT_IMPLEMENTED:
+ case DNS_ERROR_RCODE_REFUSED:
+ return EAI_FAIL; /* NO_RECOVERY */
+
+ case ERROR_TIMEOUT:
+ case DNS_ERROR_RCODE_SERVER_FAILURE:
+ case DNS_ERROR_TRY_AGAIN_LATER:
+ return EAI_AGAIN; /* TRY_AGAIN */
+
+ default:
+ return EAI_NODATA;
+ }
+
+ struct servinfo *list = NULL, *first = NULL;
+ for (PDNS_RECORD rr = pDnsRecord; rr; rr = rr->pNext)
+ {
+ if (rr->wType == DNS_TYPE_SRV)
+ {
+ PDNS_SRV_DATA rdata = &rr->Data.Srv;
+
+ if (rr->wDataLength >= sizeof(DNS_SRV_DATA) && *rdata->pNameTarget)
+ {
+ struct servinfo *si = alloc_servinfo(rdata->pNameTarget, rdata->wPort, proto);
+ if (!si)
+ {
+ freeservinfo(list);
+ status = EAI_MEMORY;
+ goto done;
+ }
+ si->prio = rdata->wPriority;
+ si->weight = rdata->wWeight;
+ si->next = list, list = si;
+ if (!first)
+ {
+ first = si;
+ }
+ }
+ }
+ }
+ if (list)
+ {
+ first->next = next;
+ *res = list;
+ status = 0;
+ }
+ else
+ {
+ status = EAI_NODATA;
+ }
+
+done:
+ DnsRecordListFree(pDnsRecord, DnsFreeParsedMessageFields);
+ return status;
+}
+
+#else
+/*
+ * Queries DNS SRV records for specified DNS domain.
+ * Returns EAI_* status and service list on success in order of receive.
+ */
+static int
+query_servinfo(const char *domain, int proto, struct servinfo *next,
+ struct servinfo **res)
+{
+ unsigned char answer[NS_MAXMSG];
+ int status;
+
+ int n = res_query(domain, ns_c_in, ns_t_srv, answer, NS_MAXMSG);
+ dmsg(D_SOCKET_DEBUG, "RES_QUERY class=%d type=%d domain=%s result=%d",
+ ns_c_in, ns_t_srv, domain, n);
+ if (n < 0)
+ {
+ switch (h_errno)
+ {
+ case HOST_NOT_FOUND:
+ return EAI_NONAME;
+
+ case NO_ADDRESS:
+#if NO_ADDRESS != NO_DATA
+ case NO_DATA:
+#endif
+ return EAI_NODATA;
+
+ case NO_RECOVERY:
+ return EAI_FAIL;
+
+ case TRY_AGAIN:
+ return EAI_AGAIN;
+ }
+ return EAI_SYSTEM;
+ }
+
+ ns_msg msg;
+ if (ns_initparse(answer, n, &msg) < 0)
+ {
+ return EAI_FAIL;
+ }
+
+ struct servinfo *list = NULL, *first = NULL;
+ for (int i = 0; i < ns_msg_count(msg, ns_s_an); i++)
+ {
+ ns_rr rr;
+
+ if (ns_parserr(&msg, ns_s_an, i, &rr) == 0 && ns_rr_type(rr) == ns_t_srv)
+ {
+ const unsigned char *rdata = ns_rr_rdata(rr);
+ char name[NS_MAXDNAME];
+
+ if (ns_rr_rdlen(rr) > 6
+ && dn_expand(ns_msg_base(msg), ns_msg_end(msg),
+ rdata + 6, name, sizeof(name)) > 0 && *name)
+ {
+ struct servinfo *si = alloc_servinfo(name, ns_get16(rdata + 4), proto);
+ if (!si)
+ {
+ freeservinfo(list);
+ status = EAI_MEMORY;
+ goto done;
+ }
+ si->prio = ns_get16(rdata);
+ si->weight = ns_get16(rdata + 2);
+ si->next = list, list = si;
+ if (!first)
+ {
+ first = si;
+ }
+ }
+ }
+ }
+ if (list)
+ {
+ first->next = next;
+ *res = list;
+ status = 0;
+ }
+ else
+ {
+ status = EAI_NODATA;
+ }
+
+done:
+ return status;
+}
+#endif
+
+/*
+ * Service structure compare function for server selection
+ * mechanism, defined in RFC 2782.
+ */
+static int
+servinfo_cmp(const void *a, const void *b)
+{
+ const struct servinfo *ae = *(struct servinfo **)a;
+ const struct servinfo *be = *(struct servinfo **)b;
+
+ /* lowest-numbered priority first */
+ if (ae->prio != be->prio)
+ {
+ return ae->prio < be->prio ? -1 : 1;
+ }
+
+ /* zero-weighted first */
+ if ((ae->weight == 0 && be->weight)
+ || (ae->weight && be->weight == 0))
+ {
+ return ae->weight < be->weight ? -1 : 1;
+ }
+
+ /* else keep received order, can't be equal */
+ return ae->order > be->order ? -1 : 1;
+}
+
+/*
+ * Sort & order service list according server selection mechanism,
+ * defined in RFC 2782.
+ * Returns service list. Although specific elements can be freed,
+ * non-empty list can never become empty.
+ */
+static struct servinfo *
+sort_servinfo(struct servinfo *list)
+{
+ struct servinfo ordered, *tail = &ordered;
+ int count = 0;
+ struct gc_arena gc = gc_new();
+
+ ASSERT(list);
+
+ /* count and number entries in reverse order */
+ for (struct servinfo *si = list; si; si = si->next)
+ {
+ si->order = count++;
+ }
+
+ struct servinfo **sorted;
+ ALLOC_ARRAY_CLEAR_GC(sorted, struct servinfo *, count, &gc);
+ for (struct servinfo *si = list; si; si = si->next)
+ {
+ sorted[si->order] = si;
+ }
+
+ /* sort records by priority and zero weight */
+ qsort(sorted, count, sizeof(sorted[0]), servinfo_cmp);
+
+ /* apply weighted selection mechanism */
+ ordered.next = NULL;
+ for (int i = 0; i < count;)
+ {
+ struct servinfo unordered;
+
+ /* compute the sum of the weights of records of the same
+ * priority and put them in the unordered list */
+ unordered.prio = sorted[i]->prio;
+ unordered.weight = 0;
+ unordered.next = NULL;
+ for (struct servinfo *prev = &unordered;
+ i < count && sorted[i]->prio == unordered.prio; i++)
+ {
+ unordered.weight += sorted[i]->weight;
+
+ /* add entry to the tail of unordered list */
+ sorted[i]->next = NULL;
+ prev->next = sorted[i], prev = sorted[i];
+ }
+
+ /* process the unordered list */
+ while (unordered.next)
+ {
+ /* choose a uniform random number between 0 and the sum
+ * computed (inclusive) */
+ int weight = get_random() % (unordered.weight + 1);
+
+ /* select the entries whose running sum value is the first
+ * in the selected order which is greater than or equal
+ * to the random number selected */
+ for (struct servinfo *si = unordered.next, *prev = &unordered;
+ si; prev = si, si = si->next)
+ {
+ /* selected entry is the next one to be contacted */
+ if (si->weight >= weight)
+ {
+ unordered.weight -= si->weight;
+
+ /* move entry to the ordered list */
+ prev->next = si->next;
+ si->next = NULL;
+ tail->next = si, tail = si;
+
+ /* in the presence of records containing weights greater
+ * than 0, records with weight 0 should have a very small
+ * chance of being selected, so skip them all after the
+ * last weighted */
+ if (unordered.weight == 0 && si->weight)
+ {
+ freeservinfo(unordered.next);
+ unordered.next = NULL;
+ }
+ break;
+ }
+ weight -= si->weight;
+ }
+ }
+ }
+
+ gc_free(&gc);
+ return ordered.next;
+}
+
+
+/*
+ * Resolves DNS SRV records for specified domain and service.
+ * Returns EAI_* status (like getaddrinfo) and service list, ordered
+ * according server selection mechanism, defined in RFC 2782.
+ */
+static int
+getservinfo(const char *domain,
+ const char *service,
+ int flags,
+ struct servinfo **res)
+{
+ static const struct {
+ int flags;
+ int proto;
+ const char *name;
+ } proto[] = {
+ { GETADDR_DATAGRAM, PROTO_UDP, "udp" },
+ { GETADDR_STREAM, PROTO_TCP_CLIENT, "tcp" }
+ };
+ struct servinfo *list = NULL;
+ int status = EAI_SOCKTYPE;
+
+ ASSERT(res);
+
+ if (!domain)
+ {
+ return EAI_NONAME;
+ }
+ if (!service)
+ {
+ return EAI_SERVICE;
+ }
+
+ int proto_flags = flags & GETADDR_PROTO_MASK;
+ for (int i = 0; i < SIZE(proto); i++)
+ {
+ if (proto_flags & proto[i].flags)
+ {
+ proto_flags &= ~proto[i].flags;
+
+ char qname[256];
+ if (!openvpn_snprintf(qname, sizeof(qname), "_%s._%s.%s",
+ service, proto[i].name, domain))
+ {
+ freeservinfo(list);
+ return EAI_MEMORY;
+ }
+
+#ifdef _WIN32
+ status = query_servinfo_win32(qname, proto[i].proto, list, &list);
+#else
+ status = query_servinfo(qname, proto[i].proto, list, &list);
+#endif
+ }
+ }
+
+ if (list)
+ {
+ *res = sort_servinfo(list);
+ status = 0;
+ }
+
+ return status;
+}
+
+void
+freeservinfo(struct servinfo *res)
+{
+ while (res)
+ {
+ struct servinfo *si = res;
+ res = res->next;
+ freeaddrinfo(si->ai);
+ free(si);
+ }
+}
+
+/*
+ * Translate IPv4/IPv6 hostname and service name into struct servinfo
+ * If resolve error, try again for resolve_retry_seconds seconds.
+ */
+int
+openvpn_getservinfo(unsigned int flags,
+ const char *hostname,
+ const char *servname,
+ int resolve_retry_seconds,
+ volatile int *signal_received,
+ int family,
+ struct servinfo **res)
+{
+ int status;
+ int sigrec = 0;
+ int msglevel = (flags & GETADDR_FATAL) ? M_FATAL : D_RESOLVE_ERRORS;
+ struct gc_arena gc = gc_new();
+ const char *print_hostname;
+ const char *print_servname;
+
+ ASSERT(res);
+
+ ASSERT(hostname || servname);
+ ASSERT(!(flags & GETADDR_HOST_ORDER));
+
+ if (hostname)
+ {
+ print_hostname = hostname;
+ }
+ else
+ {
+ print_hostname = "undefined";
+ }
+
+ if (servname)
+ {
+ print_servname = servname;
+ }
+ else
+ {
+ print_servname = "";
+ }
+
+ if (flags & GETADDR_MSG_VIRT_OUT)
+ {
+ msglevel |= M_MSG_VIRT_OUT;
+ }
+
+ if ((flags & (GETADDR_FATAL_ON_SIGNAL|GETADDR_WARN_ON_SIGNAL))
+ && !signal_received)
+ {
+ signal_received = &sigrec;
+ }
+
+ const int fail_wait_interval = 5; /* seconds */
+ /* Add +4 to cause integer division rounding up (1 + 4) = 5, (0+4)/5=0 */
+ int resolve_retries = (flags & GETADDR_TRY_ONCE) ? 1 :
+ ((resolve_retry_seconds + 4)/ fail_wait_interval);
+ const char *fmt;
+ int level = 0;
+
+ fmt = "RESOLVE: Cannot resolve service: %s:%s (%s)";
+ if ((flags & GETADDR_MENTION_RESOLVE_RETRY)
+ && !resolve_retry_seconds)
+ {
+ fmt = "RESOLVE: Cannot resolve service: %s:%s (%s) (I would have retried this name query if you had specified the --resolv-retry option.)";
+ }
+
+#ifdef ENABLE_MANAGEMENT
+ if (flags & GETADDR_UPDATE_MANAGEMENT_STATE)
+ {
+ if (management)
+ {
+ management_set_state(management,
+ OPENVPN_STATE_RESOLVE,
+ NULL,
+ NULL,
+ NULL,
+ NULL,
+ NULL);
+ }
+ }
+#endif
+
+ /*
+ * Resolve service
+ */
+ while (true)
+ {
+ dmsg(D_SOCKET_DEBUG, "GETSERVINFO flags=0x%04x family=%d host=%s service=%s",
+ flags, family, print_hostname, print_servname);
+ status = getservinfo(hostname, servname, flags, res);
+
+ if (signal_received)
+ {
+ get_signal(signal_received);
+ if (*signal_received) /* were we interrupted by a signal? */
+ {
+ if (*signal_received == SIGUSR1) /* ignore SIGUSR1 */
+ {
+ msg(level, "RESOLVE: Ignored SIGUSR1 signal received during DNS resolution attempt");
+ *signal_received = 0;
+ }
+ else
+ {
+ /* turn success into failure (interrupted syscall) */
+ if (0 == status)
+ {
+ ASSERT(res);
+ freeservinfo(*res);
+ *res = NULL;
+ status = EAI_AGAIN; /* = temporary failure */
+ errno = EINTR;
+ }
+ goto done;
+ }
+ }
+ }
+
+ /* success? */
+ if (0 == status)
+ {
+ break;
+ }
+
+ /* resolve lookup failed, should we
+ * continue or fail? */
+ level = msglevel;
+ if (resolve_retries > 0)
+ {
+ level = D_RESOLVE_ERRORS;
+ }
+
+ msg(level,
+ fmt,
+ print_hostname,
+ print_servname,
+ gai_strerror(status));
+
+ if (--resolve_retries <= 0)
+ {
+ goto done;
+ }
+
+ management_sleep(fail_wait_interval);
+
+#ifndef _WIN32
+ /* resolve failed, force resolv.conf reload */
+ res_init();
+#endif
+ }
+
+ ASSERT(res);
+
+ /* service resolve succeeded */
+
+done:
+ if (signal_received && *signal_received)
+ {
+ int level = 0;
+ if (flags & GETADDR_FATAL_ON_SIGNAL)
+ {
+ level = M_FATAL;
+ }
+ else if (flags & GETADDR_WARN_ON_SIGNAL)
+ {
+ level = M_WARN;
+ }
+ msg(level, "RESOLVE: signal received during DNS resolution attempt");
+ }
+
+ gc_free(&gc);
+ return status;
+}
+
/*
* Translate IPv4/IPv6 addr or hostname into struct addrinfo
* If resolve error, try again for resolve_retry_seconds seconds.
@@ -557,13 +1242,10 @@ openvpn_getaddrinfo(unsigned int flags,
*/
while (true)
{
-#ifndef _WIN32
- res_init();
-#endif
/* try hostname lookup */
hints.ai_flags &= ~AI_NUMERICHOST;
- dmsg(D_SOCKET_DEBUG, "GETADDRINFO flags=0x%04x ai_family=%d ai_socktype=%d",
- flags, hints.ai_family, hints.ai_socktype);
+ dmsg(D_SOCKET_DEBUG, "GETADDRINFO flags=0x%04x ai_family=%d ai_socktype=%d hostname=%s servname=%s",
+ flags, hints.ai_family, hints.ai_socktype, print_hostname, print_servname);
status = getaddrinfo(hostname, servname, &hints, res);
if (signal_received)
@@ -618,6 +1300,11 @@ openvpn_getaddrinfo(unsigned int flags,
}
management_sleep(fail_wait_interval);
+
+#ifndef _WIN32
+ /* resolve failed, force resolv.conf reload */
+ res_init();
+#endif
}
ASSERT(res);
@@ -1707,7 +2394,7 @@ resolve_bind_local(struct link_socket *sock, const sa_family_t af)
sock->local_port,
af,
flags,
- &sock->info.lsa->bind_local);
+ &sock->info.lsa->bind_local, NULL);
if (status)
{
@@ -1790,7 +2477,7 @@ resolve_remote(struct link_socket *sock,
sock->remote_host,
sock->remote_port,
sock->info.af,
- flags, &ai);
+ flags, &ai, NULL);
if (status)
{
status = openvpn_getaddrinfo(flags, sock->remote_host, sock->remote_port,
@@ -1801,6 +2488,10 @@ resolve_remote(struct link_socket *sock,
{
sock->info.lsa->remote_list = ai;
sock->info.lsa->current_remote = ai;
+ if (sock->info.lsa->current_service)
+ {
+ sock->info.lsa->current_service->ai = ai;
+ }
dmsg(D_SOCKET_DEBUG, "RESOLVE_REMOTE flags=0x%04x phase=%d rrs=%d sig=%d status=%d",
flags,
@@ -1851,7 +2542,107 @@ done:
gc_free(&gc);
}
+void
+do_resolve_service(struct context *c)
+{
+ struct connection_entry *ce = &c->options.ce;
+
+ if (ce->remote_srv
+ && !c->c1.link_socket_addr.service_list)
+ {
+ if (ce->remote)
+ {
+ unsigned int flags = sf2gaf(GETADDR_RESOLVE|
+ GETADDR_UPDATE_MANAGEMENT_STATE|
+ GETADDR_SERVICE,
+ c->options.sockflags);
+ int retry = 0;
+ int status = -1;
+ struct servinfo *si;
+
+ if (proto_is_dgram(ce->proto) || ce->proto == PROTO_AUTO)
+ {
+ flags |= GETADDR_DATAGRAM;
+ }
+ if (proto_is_stream(ce->proto) || ce->proto == PROTO_AUTO)
+ {
+ flags |= GETADDR_STREAM;
+ }
+
+ if (c->options.sockflags & SF_HOST_RANDOMIZE)
+ {
+ flags |= GETADDR_RANDOMIZE;
+ }
+
+ if (c->options.resolve_retry_seconds == RESOLV_RETRY_INFINITE)
+ {
+ flags |= (GETADDR_TRY_ONCE | GETADDR_FATAL);
+ retry = 0;
+ }
+ else if (c->options.resolve_retry_seconds)
+ {
+ flags |= GETADDR_FATAL;
+ retry = c->options.resolve_retry_seconds;
+ }
+ else
+ {
+ flags |= (GETADDR_FATAL | GETADDR_MENTION_RESOLVE_RETRY);
+ retry = 0;
+ }
+
+ status = get_cached_dns_entry(c->c1.dns_cache,
+ ce->remote,
+ ce->remote_port,
+ ce->af,
+ flags, NULL, &si);
+ if (status)
+ {
+ status = openvpn_getservinfo(flags, ce->remote, ce->remote_port,
+ retry, &c->sig->signal_received, ce->af, &si);
+ }
+
+ if (status == 0)
+ {
+ c->c1.link_socket_addr.service_list = si;
+ c->c1.link_socket_addr.current_service = NULL;
+
+ /* advance to the first appropriate service */
+ while (si)
+ {
+ /* map in current service */
+ if (!c->c1.link_socket_addr.current_service
+ && options_mutate_ce_servinfo(&c->options, si))
+ {
+ c->c1.link_socket_addr.current_service = si;
+ }
+
+ /* log discovered service hosts */
+ msg(D_RESOLVE_INFO, "DNS SRV remote host: %s:%s,%s prio %u weight %u",
+ np(si->hostname), np(si->servname),
+ proto2ascii(si->proto, ce->af, false),
+ si->prio, si->weight);
+
+ si = si->next;
+ }
+ if (!c->c1.link_socket_addr.current_service)
+ {
+ status = EAI_NODATA;
+ }
+ dmsg(D_SOCKET_DEBUG, "RESOLVE_SERVICE flags=0x%04x rrs=%d sig=%d status=%d",
+ flags,
+ retry,
+ c->sig->signal_received,
+ status);
+ }
+
+ if (!c->sig->signal_received && status != 0)
+ {
+ c->sig->signal_received = SIGUSR1;
+ }
+ }
+ }
+}
struct link_socket *
link_socket_new(void)
@@ -3161,16 +3952,19 @@ static const struct proto_names proto_names[] = {
{"tcp-server", "TCP_SERVER", AF_UNSPEC, PROTO_TCP_SERVER},
{"tcp-client", "TCP_CLIENT", AF_UNSPEC, PROTO_TCP_CLIENT},
{"tcp", "TCP", AF_UNSPEC, PROTO_TCP},
+ {"auto", "AUTO", AF_UNSPEC, PROTO_AUTO},
/* force IPv4 */
{"udp4", "UDPv4", AF_INET, PROTO_UDP},
{"tcp4-server","TCPv4_SERVER", AF_INET, PROTO_TCP_SERVER},
{"tcp4-client","TCPv4_CLIENT", AF_INET, PROTO_TCP_CLIENT},
{"tcp4", "TCPv4", AF_INET, PROTO_TCP},
+ {"auto4", "AUTOv4", AF_INET, PROTO_AUTO},
/* force IPv6 */
{"udp6","UDPv6", AF_INET6, PROTO_UDP},
{"tcp6-server","TCPv6_SERVER", AF_INET6, PROTO_TCP_SERVER},
{"tcp6-client","TCPv6_CLIENT", AF_INET6, PROTO_TCP_CLIENT},
- {"tcp6","TCPv6", AF_INET6, PROTO_TCP},
+ {"tcp6", "TCPv6", AF_INET6, PROTO_TCP},
+ {"auto6", "AUTOv6", AF_INET6, PROTO_AUTO},
};
bool
@@ -3180,14 +3974,21 @@ proto_is_net(int proto)
{
ASSERT(0);
}
- return proto != PROTO_NONE;
+ return proto != PROTO_NONE && proto != PROTO_AUTO;
}
+
bool
proto_is_dgram(int proto)
{
return proto_is_udp(proto);
}
+bool
+proto_is_stream(int proto)
+{
+ return proto_is_tcp(proto);
+}
+
bool
proto_is_udp(int proto)
{
@@ -3266,6 +4067,11 @@ proto2ascii_all(struct gc_arena *gc)
for (i = 0; i < SIZE(proto_names); ++i)
{
+ if (proto_names[i].proto == PROTO_NONE
+ || proto_names[i].proto == PROTO_AUTO)
+ {
+ continue;
+ }
if (i)
{
buf_printf(&out, " ");
@@ -40,6 +40,11 @@
*/
#define OPENVPN_PORT "1194"
+/*
+ * OpenVPN's default service name for DNS SRV discovery.
+ */
+#define OPENVPN_SERVICE "openvpn"
+
/*
* Number of seconds that "resolv-retry infinite"
* represents.
@@ -71,13 +76,29 @@ struct openvpn_sockaddr
} addr;
};
+/* struct to hold resolved service targets */
+struct servinfo
+{
+ const char *hostname;
+ const char *servname;
+ int proto;
+ int order;
+ unsigned short prio;
+ unsigned short weight;
+ struct addrinfo *ai;
+ struct servinfo *next;
+};
+
/* struct to hold preresolved host names */
struct cached_dns_entry {
const char *hostname;
const char *servname;
int ai_family;
int flags;
- struct addrinfo *ai;
+ union {
+ struct addrinfo *ai;
+ struct servinfo *si;
+ };
struct cached_dns_entry *next;
};
@@ -106,6 +127,9 @@ struct link_socket_addr
struct addrinfo *remote_list; /* complete remote list */
struct addrinfo *current_remote; /* remote used in the
* current connection attempt */
+ struct servinfo *service_list; /* complete service list */
+ struct servinfo *current_service; /* service used in the
+ * current connection attempt */
struct link_socket_actual actual; /* reply to this address */
};
@@ -338,6 +362,8 @@ void link_socket_init_phase2(struct link_socket *sock,
void do_preresolve(struct context *c);
+void do_resolve_service(struct context *c);
+
void socket_adjust_frame_parameters(struct frame *frame, int proto);
void frame_adjust_path_mtu(struct frame *frame, int pmtu, int proto);
@@ -486,6 +512,7 @@ socket_descriptor_t socket_do_accept(socket_descriptor_t sd,
bool proto_is_net(int proto);
bool proto_is_dgram(int proto);
+bool proto_is_stream(int proto);
bool proto_is_udp(int proto);
@@ -532,8 +559,12 @@ bool unix_socket_get_peer_uid_gid(const socket_descriptor_t sd, int *uid, int *g
#define GETADDR_RANDOMIZE (1<<9)
#define GETADDR_PASSIVE (1<<10)
#define GETADDR_DATAGRAM (1<<11)
+#define GETADDR_STREAM (1<<12)
+#define GETADDR_SERVICE (1<<13)
+#define GETADDR_PROTO_MASK (GETADDR_DATAGRAM|GETADDR_STREAM)
#define GETADDR_CACHE_MASK (GETADDR_DATAGRAM|GETADDR_PASSIVE)
+#define GETADDR_CACHE_SERVICE_MASK (GETADDR_PROTO_MASK|GETADDR_SERVICE)
/**
* Translate an IPv4 addr or hostname from string form to in_addr_t
@@ -561,6 +592,28 @@ int openvpn_getaddrinfo(unsigned int flags,
int ai_family,
struct addrinfo **res);
+int openvpn_getservinfo(unsigned int flags,
+ const char *hostname,
+ const char *servname,
+ int resolve_retry_seconds,
+ volatile int *signal_received,
+ int family,
+ struct servinfo **res);
+
+void freeservinfo(struct servinfo *res);
+
+inline static void
+gc_freeaddrinfo_callback(void *addr)
+{
+ freeaddrinfo((struct addrinfo *) addr);
+}
+
+inline static void
+gc_freeservinfo_callback(void *addr)
+{
+ freeservinfo((struct servinfo *) addr);
+}
+
/*
* Transport protocol naming and other details.
*/
@@ -575,6 +628,7 @@ enum proto_num {
PROTO_TCP,
PROTO_TCP_SERVER,
PROTO_TCP_CLIENT,
+ PROTO_AUTO,
PROTO_N
};
@@ -38,6 +38,7 @@
#ifdef _WIN32
#include <windows.h>
+#include <windns.h>
#include <winsock2.h>
#include <tlhelp32.h>
#define sleep(x) Sleep((x)*1000)
@@ -176,6 +177,10 @@
#include <netinet/in.h>
#endif
+#ifdef HAVE_ARPA_NAMESER_H
+#include <arpa/nameser.h>
+#endif
+
#ifdef HAVE_RESOLV_H
#include <resolv.h>
#endif
DNS SRV host discovery allows to have multiple OpenVPN servers for a single domain w/o explicit profile enumeration, to move services from host to host with little fuss, and to designate hosts as primary servers for a service and others as backups. Feature has been asked several times already, useful in case of huge ammount of clients & servers deployed. Patch introduces "--remote-srv domain [service] [proto]" option, which enables DNS SRV discovery and optionally allows to change default "openvpn" service and default "auto" protocol to the specified values. Client will try to resolve "_service._proto.domain" name via DNS and use returned DNS SRV records as OpenVPN remote server list ordered by server selection mechanism defined in RFC 2782: A client MUST attempt to contact the target host with the lowest-numbered priority field value it can reach, target hosts with the same priority SHOULD be tried in an order defined by the weight field. The weight field specifies a relative weight for entries with the same priority. Larger weights SHOULD be given a proportionately higher probability of being selected. Domain administrators SHOULD use Weight 0 when there isn't any server selection to do. In the presence of records containing weights greater than 0, records with weight 0 SHOULD have a very small chance of being selected. Example: instead of multiple remotes in order: remote s1.example.net 1194 udp remote s2.example.net 1194 udp remote s3.example.net 1194 udp remote s4.example.net 1194 tcp now it's possible to specify just one remote-srv: remote-srv example.net and configure following DNS SRV records: name prio weight port host _openvpn._udp.example.net IN SRV 10 60 1194 s1.example.net _openvpn._udp.example.net IN SRV 10 40 1194 s2.example.net _openvpn._udp.example.net IN SRV 10 0 1194 s3.example.net _openvpn._tcp.example.net IN SRV 20 0 443 s4.example.net Client will first try to resolve "_openvpn._udp.example.net" and "_openvpn._tcp.example.net" names. Next, "s1.example.net", "s2.example.net" and "s3.example.net" will be ordered before "s4.example.net" as their priority 10 is smaller than 20. Next, "s1.example.net", "s2.example.net" and "s3.example.net" will be randomly ordered with weight probability - first will be either "s1.example.net" with probability 60% or "s2.example.net" with 40% or "s3.example.net" with almost zero probability. Next, if "s1.example.net" is picked as first, second server will be either "s2.example.net" with almost 100% probability or "s3.example.net" instead. Next, if "s2.example.net" is picked as second, "s3.example.net" will be skipped due zero weight. "s4.example.net" will be the last one as the only server with priority 20. Finally, servers will be resolved and accessed in this order. If "_openvpn._udp.example.net" and "_openvpn._udp.example.net" can't be resolved or no valid records were returned, client will move on to the next connection entry. Tested on Linux & Windows 10. v2: use DNS SRV for feature naming change option name to --remote-service-discovery add --remote-service-discovery [service] optional parameter support rewrite man, add algo/prio/weight description and examples fix random weight selection was not implicit remove pulled REMOTE_DISCOVERY support, not needed split windows/unix-specific parts into extra functions rename functions into servinfo scope, add doxygen comments when appropriate remove addrinfo hack, use servinfo containers of addrinfo list instead better proxy support (tcp mode not supported so far) log discovery attempts and results, if enabled v3: complete logic rewrite use separate --remote-srv [service] [proto] option remove fallback, same is achieved with additiona --remote/--remote-srv add "auto" protocol support to allow both udp & tcp hosts be discovered add support for tcp / http proxy (natively) man update Signed-off-by: Vladislav Grishenko <themiron@yandex-team.ru> --- configure.ac | 2 +- doc/man-sections/client-options.rst | 88 ++- doc/management-notes.txt | 6 + src/openvpn/Makefile.am | 2 +- src/openvpn/buffer.h | 5 - src/openvpn/errlevel.h | 1 + src/openvpn/init.c | 57 +- src/openvpn/openvpn.vcxproj | 8 +- src/openvpn/options.c | 238 ++++++-- src/openvpn/options.h | 4 + src/openvpn/socket.c | 836 +++++++++++++++++++++++++++- src/openvpn/socket.h | 56 +- src/openvpn/syshead.h | 5 + 13 files changed, 1231 insertions(+), 77 deletions(-)