Port plugin extension

doc/METADATA.ini

@@ -553,6 +553,21 @@ usedby/plugin= network ipaddr
 description= check if value resolves correctly to an ipaddr
 	empty value uses either ipv4 or ipv6
 
+[check/port]
+type= string
+status = implemented
+usedby/plugin= network
+description= check if the given port is either a service under /etc/services or
+	is between 0 - 65535 (both inclusive)
+
+[check/port/listen]
+type= string
+status = implemented
+usedby/plugin= network
+description= check if the given port is either a service under /etc/services or
+     is between 0 - 65535 (both inclusive) and is unused so that potential
+     applications can start with that port
+
 [check/format]
 type= string
 status= idea

doc/news/_preparation_next_release.md

@@ -120,6 +120,9 @@ This new plugin parses a subset of YAML using a parser generated by [Bison](http
 The `network` plugin now also allows for non-numerical hosts (i.e. "localhost") to be set and tries to
 resolve it via DNS. *(Michael Zronek)*
 
+The `network` plugin also supports port declarations to check if a portnumber is valid
+or if the port is available to use. *(Michael Zronek)*
+
 ### <<Plugin2>>
 
 - <<TODO>>

src/error/specification

@@ -1258,3 +1258,27 @@ severity:warning
 ingroup:plugin
 module:gpgme
 macro:GPGME_INVALID_RECIPIENT
+
+number:201
+description:The given port was not withing a valid range
+severity:error
+ingroup:plugin
+module:network
+
+number:202
+description:Could not find service name for port declaration
+severity:error
+ingroup:plugin
+module:network
+
+number:203
+description:Could not use port as it is already in use
+severity:error
+ingroup:plugin
+module:network
+
+number:204
+description:Connection Error occured
+severity:error
+ingroup:plugin
+module:network

src/plugins/network/README.md

@@ -5,7 +5,7 @@
 - infos/needs =
 - infos/placements = presetstorage
 - infos/status = maintained unittest nodep libc nodoc
-- infos/metadata = check/ipaddr
+- infos/metadata = check/ipaddr check/port check/port/listen
 - infos/description = Checks keys if they contain a valid ip address
 
 ## Introduction
@@ -14,6 +14,10 @@ This plugin is a check plugin that checks if a key contains a valid ip
 address. It uses the `POSIX.1-2001` interface `getaddrinfo()` in order
 to check if an ip address is valid.
 
+Furthermore `getaddrinfo()` is used in `check/port` to resolve a port by its service name
+which is defined under `/etc/services`. The portname is translated to the respective portnumber.
+The plugin can be used to check for valid port numbers and if the set port is free to use.
+
 ## Purpose
 
 While, in theory, a regular expression can express if a string is a
@@ -36,7 +40,15 @@ it to implement this plugin.
 
 Every key tagged with the metakey `check/ipaddr` will be checked
 using `getaddrinfo()`.  If additionally the values `ipv4` or `ipv6`
-are supplied, the address family will be specified. If supplied only
-numerical hosts are allowed. If left empty, the plugin will resolve 
-domain names and look if it is reachable (i.e. "localhost" should most
-likely work on any system)
+are supplied, the address family will be specified.
+
+If `check/port` is specified on a given key, the plugin will validate if the port is a
+correct number between 1 and 65535.
+
+If `check/port/listen` is specified, the plugin will check if the application can be started
+and listen on the given port.
+
+## Future Work
+
+`check/port/connect` to check if the port can be pinged/reached (usually for clients).
+If not reachable, users receive a warning. A correct timeout setting will be problematic though.

src/plugins/network/network.c

@@ -50,6 +50,70 @@ int elektraNetworkAddrInfo (Key * toCheck)
 	return 0;
 }
 
+int elektraPortInfo(Key * toCheck, Key * parentKey) {
+	const Key * meta = keyGetMeta (toCheck, "check/port");
+	const Key * listenMeta = keyGetMeta (toCheck, "check/port/listen");
+	if (!meta && !listenMeta) return 0; /* No check to do */
+	char *endptr = NULL;
+	long portNumber = strtol(keyString(toCheck), &endptr, 10);
+	int portNumberNetworkByteOrder;
+
+	if (*endptr == '\0') {
+		if (portNumber < 0 || portNumber > 65535 || *endptr != 0) {
+			ELEKTRA_SET_ERRORF(201, parentKey, "Port %d on key %s was not within 0 - 65535",
+							   portNumber, keyName(toCheck));
+			return -1;
+		}
+		portNumberNetworkByteOrder = htons(portNumber);
+	} else {
+		struct servent* service;
+		service = getservbyname(keyString(toCheck), NULL); //NULL means we accept both tcp and udp
+		if (service == NULL) {
+			ELEKTRA_SET_ERRORF(202, parentKey, "Could not find service with name %s on key %s",
+							   keyString(toCheck), keyName(toCheck));
+			return -1;
+		}
+		portNumberNetworkByteOrder = service->s_port;
+	}
+
+	//Check if we can connect to it
+	if (!listenMeta) return 0; /* No check to do */
+
+	char *hostname = "localhost";
+
+	int sockfd;
+	struct sockaddr_in serv_addr;
+	struct hostent *server;
+	sockfd = socket(AF_INET, SOCK_STREAM, 0);
+	if (sockfd < 0) {
+		ELEKTRA_SET_ERROR(204, parentKey, "Could not open a socket");
+	}
+
+	server = gethostbyname(hostname);
+	if (server == NULL) {
+		ELEKTRA_SET_ERRORF(204, parentKey, "Could not connect to %s: No such host",
+						   hostname);
+		return -1;
+	}
+
+	bzero((char *) &serv_addr, sizeof(serv_addr));
+	serv_addr.sin_family = AF_INET;
+	bcopy((char *)server->h_addr,
+		  (char *)&serv_addr.sin_addr.s_addr,
+		  server->h_length);
+
+	serv_addr.sin_port = (in_port_t) portNumberNetworkByteOrder;
+	if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) == 0) {
+		close(sockfd);
+		ELEKTRA_SET_ERRORF(203, parentKey, "Port %s is already in use which was specified on key %s",
+						   keyString(toCheck), keyName(toCheck));
+		return -1;
+	}
+	close(sockfd);
+
+	return 0;
+}
+
 int elektraNetworkGet (Plugin * handle ELEKTRA_UNUSED, KeySet * returned, Key * parentKey ELEKTRA_UNUSED)
 {
 	/* configuration only */
@@ -61,6 +125,8 @@ int elektraNetworkGet (Plugin * handle ELEKTRA_UNUSED, KeySet * returned, Key *
 			     keyNew ("system/elektra/modules/network/exports/set", KEY_FUNC, elektraNetworkSet, KEY_END),
 			     keyNew ("system/elektra/modules/network/exports/elektraNetworkAddrInfo", KEY_FUNC, elektraNetworkAddrInfo,
 				     KEY_END),
+				 keyNew ("system/elektra/modules/network/exports/elektraPortInfo", KEY_FUNC, elektraNetworkAddrInfo,
+					 KEY_END),
 #include "readme_network.c"
 			     keyNew ("system/elektra/modules/network/infos/version", KEY_VALUE, PLUGINVERSION, KEY_END), KS_END));
 	ksDel (n);
@@ -72,7 +138,6 @@ int elektraNetworkSet (Plugin * handle ELEKTRA_UNUSED, KeySet * returned, Key *
 {
 	/* check all keys */
 	Key * cur;
-
 	ksRewind (returned);
 	while ((cur = ksNext (returned)) != 0)
 	{
@@ -92,6 +157,10 @@ int elektraNetworkSet (Plugin * handle ELEKTRA_UNUSED, KeySet * returned, Key *
 			elektraFree (errmsg);
 			return -1;
 		}
+		int p = elektraPortInfo(cur, parentKey);
+		if (p != 0) {
+			return -1;
+		}
 	}
 
 	return 1; /* success */

src/plugins/network/network.h

@@ -21,6 +21,7 @@
 #include <unistd.h>
 
 int elektraNetworkAddrInfo (Key * toCheck);
+int elektraPortInfo(Key * toCheck, Key * parentKey);
 
 int elektraNetworkGet (Plugin * handle, KeySet * ks, Key * parentKey);
 int elektraNetworkSet (Plugin * handle, KeySet * ks, Key * parentKey);

src/plugins/network/testmod_network.c

@@ -17,6 +17,9 @@
 #include <tests.h>
 
 #define PLUGIN_NAME "network"
+
+static void testPorts() ;
+
 #include "../ipaddr/test_ipaddr.h"
 
 int main (int argc, char ** argv)
@@ -27,8 +30,53 @@ int main (int argc, char ** argv)
 	init (argc, argv);
 
 	testIPAll ();
+	testPorts ();
 
 	print_result ("testmod_network");
 
 	return nbError;
 }
+
+static void testPort (char const * const port, const int ret, char const * const version, char const * const metaName)
+{
+	Key * parentKey = keyNew ("user/tests/port", KEY_VALUE, "", KEY_END);
+	KeySet * conf = ksNew (0, KS_END);
+	KeySet * ks = ksNew (10, keyNew ("user/test/port/totest", KEY_VALUE, port, KEY_META, metaName, version, KEY_END), KS_END);
+	PLUGIN_OPEN (PLUGIN_NAME);
+	const int pluginStatus = plugin->kdbSet (plugin, ks, parentKey);
+	char message[200];
+	(void) snprintf (message, 200, "validation of %s “%s” returned %d instead of %d", version[0] == '\0' ? "Port" : version, port,
+					 pluginStatus, ret);
+	succeed_if (pluginStatus == ret, message);
+	ksDel (ks);
+	keyDel (parentKey);
+	PLUGIN_CLOSE ();
+}
+
+static inline void testPortAny (char const * const port, int ret)
+{
+	testPort (port, ret, "", "check/port");
+}
+
+static inline void testListenPortAny (char const * const port, int ret)
+{
+	testPort (port, ret, "", "check/port/listen");
+}
+
+static void testPorts() {
+	testPortAny("0", 1);
+	testPortAny("1234", 1);
+	testPortAny("65535", 1);
+	testPortAny("ssh", 1);
+	testPortAny("https", 1);
+
+	testPortAny("65536", -1);
+	testPortAny("-1", -1);
+	testPortAny("22d", -1);
+	testPortAny("myInvalidServiceName", -1);
+
+	//These tests aren't portable I guess
+	testListenPortAny("http", -1);
+	testListenPortAny("8080", 1);
+
+}