stream: Add basic stream service for systemd sockets

This allows systemd socket activation by passing URIs such as systemd://foo
to plugins such as VICI.

For example setting charon.plugins.vici.socket = systemd://vici, a
systemd socket file descriptor with the name "vici" will be picked up.

So these would be the corresponding unit options:

  [Socket]
  FileDescriptorName=vici
  Service=strongswan.service

  ListenStream=/run/charon.vici

The implementation currently is very basic and right now only the first
file descriptor for a particular identifier is picked up if there are
multiple socket units with the same FileDescriptorName.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

Closes strongswan/strongswan#79.

src/libstrongswan/Makefile.am

@@ -96,6 +96,7 @@ fetcher/fetcher_manager.h eap/eap.h pen/pen.h ipsec/ipsec_types.h \
 networking/host.h networking/host_resolver.h networking/packet.h \
 networking/tun_device.h networking/streams/stream.h \
 networking/streams/stream_unix.h networking/streams/stream_service_unix.h \
+networking/streams/stream_service_systemd.h \
 networking/streams/stream_tcp.h networking/streams/stream_service_tcp.h \
 networking/streams/stream_service.h networking/streams/stream_manager.h \
 resolver/resolver.h resolver/resolver_response.h resolver/rr_set.h \
@@ -192,6 +193,12 @@ if USE_LIBCAP
   libstrongswan_la_LIBADD += -lcap
 endif
 
+if USE_SYSTEMD
+  AM_CPPFLAGS += $(systemd_CFLAGS) -DUSE_SYSTEMD
+  libstrongswan_la_SOURCES += networking/streams/stream_service_systemd.c
+  libstrongswan_la_LIBADD += $(systemd_LIBS)
+endif
+
 EXTRA_DIST = \
 asn1/oid.txt asn1/oid.pl \
 crypto/proposal/proposal_keywords_static.txt \

src/libstrongswan/networking/streams/stream_manager.c

@@ -21,6 +21,9 @@
 # include "stream_unix.h"
 # include "stream_service_unix.h"
 #endif
+#ifdef USE_SYSTEMD
+# include "stream_service_systemd.h"
+#endif
 
 #include <threading/rwlock.h>
 
@@ -241,6 +244,9 @@ stream_manager_t *stream_manager_create()
 	add_stream(this, "unix://", stream_create_unix);
 	add_service(this, "unix://", stream_service_create_unix);
 #endif
+#ifdef USE_SYSTEMD
+	add_service(this, "systemd://", stream_service_create_systemd);
+#endif
 
 	return &this->public;
 }

src/libstrongswan/networking/streams/stream_service_systemd.c

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2017 aszlig
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <systemd/sd-daemon.h>
+
+#include <library.h>
+
+/**
+ * See header
+ */
+stream_service_t *stream_service_create_systemd(char *uri, int backlog)
+{
+	int i, num_fds, fd;
+	char **fdmap;
+
+	if (!strpfx(uri, "systemd://"))
+	{
+		DBG1(DBG_NET, "invalid stream URI: '%s'", uri);
+		return NULL;
+	}
+	uri += strlen("systemd://");
+
+	num_fds = sd_listen_fds_with_names(0, &fdmap);
+	if (num_fds <= 0)
+	{
+		DBG1(DBG_NET, "no systemd sockets for '%s'", uri);
+		return NULL;
+	}
+
+	for (i = 0, fd = -1; i < num_fds; i++)
+	{
+		if (fd == -1 && streq(fdmap[i], uri))
+		{
+			fd = SD_LISTEN_FDS_START + i;
+		}
+		free(fdmap[i]);
+	}
+	free(fdmap);
+
+	if (fd == -1)
+	{
+		DBG1(DBG_NET, "unable to find systemd FD for '%s'", uri);
+		return NULL;
+	}
+	return stream_service_create_from_fd(fd);
+}

src/libstrongswan/networking/streams/stream_service_systemd.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2017 aszlig
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/**
+ * @defgroup stream_service_systemd stream_service_systemd
+ * @{ @ingroup stream
+ */
+
+#ifndef STREAM_SERVICE_SYSTEMD_H_
+#define STREAM_SERVICE_SYSTEMD_H_
+
+/**
+ * Create a service instance for systemd sockets.
+ *
+ * @param uri		URI with FD identifier, must start with "systemd://"
+ * @param backlog	size of the backlog queue (ignored)
+ * @return			stream_service instance, NULL on failure
+ */
+stream_service_t *stream_service_create_systemd(char *uri, int backlog);
+
+#endif /** STREAM_SERVICE_SYSTEMD_H_ @}*/