Added support for connecting the hub to an upstream master hub (slave mode).

.gitignore

@@ -14,6 +14,7 @@ uhub-admin
 adcrush
 uhub
 build-stamp
+build.ninja
 debian/files
 debian/uhub.debhelper.log
 debian/uhub.postinst.debhelper
@@ -22,3 +23,4 @@ debian/uhub.prerm.debhelper
 debian/uhub.substvars
 uhub-passwd
 src/version.h
+

CMakeLists.txt

@@ -36,6 +36,10 @@ if (SSL_SUPPORT)
 	endif()
 endif()
 
+if (LINK_SUPPORT)
+	add_definitions(-DLINK_SUPPORT)
+endif()
+
 if (SYSTEMD_SUPPORT)
         INCLUDE(FindPkgConfig)
         pkg_search_module(SD_DAEMON REQUIRED libsystemd-daemon)
@@ -200,7 +204,7 @@ if (RELEASE)
 	add_definitions(-DNDEBUG)
 else()
 	set(CMAKE_BUILD_TYPE Debug)
-	# add_definitions(-DDEBUG)
+	add_definitions(-DDEBUG)
 endif()
 
 if (UNIX)

src/adc/adcconst.h

@@ -1,6 +1,6 @@
 /*
  * uhub - A tiny ADC p2p connection hub
- * Copyright (C) 2007-2012, Jan Vidar Krey
+ * Copyright (C) 2007-2013, Jan Vidar Krey
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -34,6 +34,7 @@ typedef uint32_t fourcc_t;
 
 /* default welcome protocol support message, as sent by this server */
 #define ADC_PROTO_SUPPORT "ADBASE ADTIGR ADPING ADUCMD"
+#define ADC_PROTO_LINK_SUPPORT "ADTIGR ADLINK"
 
 /* Server sent commands */
 #define ADC_CMD_ISID FOURCC('I','S','I','D')
@@ -101,6 +102,12 @@ typedef uint32_t fourcc_t;
 #define ADC_CMD_HCMD FOURCC('H','C','M','D')
 #define ADC_CMD_ICMD FOURCC('I','C','M','D')
 
+/* Link commands */
+#define ADC_CMD_LSUP FOURCC('L','S','U','P') /* Link support handshake */
+#define ADC_CMD_LINF FOURCC('L','I','N','F') /* Hub link info */
+#define ADC_CMD_LGPA FOURCC('L','G','P','A') /* Hub link get password */
+#define ADC_CMD_LPAS FOURCC('L','P','A','S') /* Hub link password */
+#define ADC_CMD_LSTA FOURCC('L','S','T','A') /* Hub link status */
 
 #define ADC_INF_FLAG_IPV4_ADDR          "I4" /* ipv4 address */
 #define ADC_INF_FLAG_IPV6_ADDR          "I6" /* ipv6 address */

src/adc/message.c

@@ -1,6 +1,6 @@
 /*
  * uhub - A tiny ADC p2p connection hub
- * Copyright (C) 2007-2010, Jan Vidar Krey
+ * Copyright (C) 2007-2013, Jan Vidar Krey
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -178,6 +178,7 @@ int adc_msg_get_arg_offset(struct adc_message* msg)
 		
 		case 'I':
 		case 'H':
+		case 'L':
 			return 4;
 			
 		case 'B':
@@ -383,8 +384,9 @@ struct adc_message* adc_msg_parse(const char* line, size_t length)
 			ok = 0;
 			break;
 
-		case 'I':
+		case 'I': /* Hub to client */
-		case 'H':
+		case 'H': /* Clien to hub */
+		case 'L': /* hub to hub Link */
 			ok = (length > 3);
 			break;
 
@@ -787,6 +789,16 @@ int adc_msg_add_argument(struct adc_message* cmd, const char* string)
 	return 0;
 }
 
+int adc_msg_add_argument_string(struct adc_message* cmd, const char* string)
+{
+	char* arg = adc_msg_escape(string);
+	int ret;
+	if (!arg) return -1;
+	ret = adc_msg_add_argument(cmd, arg);
+	hub_free(arg);
+	return ret;
+}
+
 
 char* adc_msg_get_argument(struct adc_message* cmd, int offset)
 {
@@ -868,21 +880,21 @@ int adc_msg_get_argument_index(struct adc_message* cmd, const char prefix[2])
 
 
 
-int adc_msg_escape_length(const char* str)
+size_t adc_msg_escape_length(const char* str)
 {
-	int add = 0;
+	size_t add = 0;
-	int n = 0;
+	size_t n = 0;
 	for (; str[n]; n++)
 		if (str[n] == ' ' || str[n] == '\n' || str[n] == '\\') add++;
 	return n + add;
 }
 
 
-int adc_msg_unescape_length(const char* str)
+size_t adc_msg_unescape_length(const char* str)
 {
-	int add = 0;
+	size_t add = 0;
-	int n = 0;
+	size_t n = 0;
-	int escape = 0;
+	size_t escape = 0;
 	for (; str[n]; n++)
 	{
 		if (escape)
@@ -998,3 +1010,20 @@ char* adc_msg_escape(const char* string)
 	return str;
 }
 
+enum msg_type adc_msg_get_type(const struct adc_message* msg)
+{
+	switch (msg->cache[0])
+	{
+		case 'B': return msg_type_client_broadcast;
+		case 'C': return msg_type_client_to_client;
+		case 'D': return msg_type_client_direct;
+		case 'E': return msg_type_client_echo;
+		case 'F': return msg_type_client_feature;
+		case 'H': return msg_type_client_to_hub;
+		case 'I': return msg_type_hub_to_client;
+		case 'L': return msg_type_link_to_link;
+		case 'U': return msg_type_hub_to_client_udp;
+	}
+	return msg_type_unknown;
+}
+

src/adc/message.h

@@ -1,6 +1,6 @@
 /*
  * uhub - A tiny ADC p2p connection hub
- * Copyright (C) 2007-2010, Jan Vidar Krey
+ * Copyright (C) 2007-2013, Jan Vidar Krey
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -43,6 +43,20 @@ enum msg_status_level
 	status_level_fatal = 2, /* Fatal error (disconnect) */
 };
 
+enum msg_type
+{
+	msg_type_unknown           = 0,
+	msg_type_client_broadcast  = 'B',
+	msg_type_client_to_client  = 'C',
+	msg_type_client_direct     = 'D',
+	msg_type_client_echo       = 'E',
+	msg_type_client_feature    = 'F',
+	msg_type_client_to_hub     = 'H',
+	msg_type_hub_to_client     = 'I',
+	msg_type_link_to_link      = 'L',
+	msg_type_hub_to_client_udp = 'U',
+};
+
 /**
  * Increase the reference counter for an ADC message struct.
  * NOTE: Always use the returned value, and not the passed value, as
@@ -171,6 +185,13 @@ extern int adc_msg_replace_named_argument(struct adc_message* cmd, const char pr
  */
 extern int adc_msg_add_argument(struct adc_message* cmd, const char* string);
 
+/**
+ * Append a string argumnent.
+ * The string will automatcally be escaped.
+ * @return  0 if successful, or -1 if an error occured (out of memory).
+ */
+extern int adc_msg_add_argument_string(struct adc_message* cmd, const char* string);
+
 /**
  * Append a named argument
  *
@@ -216,6 +237,12 @@ extern int adc_msg_unescape_to_target(const char* string, char* target, size_t t
  */
 extern char* adc_msg_escape(const char* string);
 
+/**
+ * Calculate the length str would be after escaping.
+ * Does not include any NULL terminator.
+ */
+size_t adc_msg_escape_length(const char* str);
+
 /**
  * This will ensure a newline is at the end of the command.
  */
@@ -234,4 +261,6 @@ void adc_msg_unterminate(struct adc_message* cmd);
  */
 int adc_msg_get_arg_offset(struct adc_message* msg);
 
+enum msg_type adc_msg_get_type(const struct adc_message* msg);
+
 #endif /* HAVE_UHUB_COMMAND_H */

src/core/config.c

@@ -102,7 +102,7 @@ static int config_parse_line(char* line, int line_count, void* ptr_data)
 	data = strip_white_space(data);
 	data = strip_off_quotes(data);
 
-	if (!*key || !*data)
+	if (!*key /*|| !*data*/)
 	{
 		LOG_FATAL("Configuration parse error on line %d", line_count);
 		return -1;

src/core/config.xml

@@ -165,6 +165,36 @@
 		<since>0.3.2</since>
 	</option>
 
+	<option name="hub_link_enabled" type="boolean" default="0">
+		<short>Allow other hubs to link to this hub</short>
+		<description><![CDATA[
+			This allows multiple hubs to link to this hub so
+			that users on the different hubs appear as being on one hub.
+			This is useful for distributing or load balancing large hubs.
+		]]></description>
+		<since>0.5.0</since>
+		<ifdef>LINK_SUPPORT</ifdef>
+	</option>
+
+	<option name="hub_link_secret" type="string" default="">
+		<short>A secret token required to accept hub linking</short>
+		<description><![CDATA[
+			This should be a secret token needed to authorize hubs
+			linking into this one.
+		]]></description>
+		<since>0.5.0</since>
+		<ifdef>LINK_SUPPORT</ifdef>
+	</option>
+
+	<option name="hub_link_connect" type="string" default="">
+		<short>Connect this to hub to another hub</short>
+		<description><![CDATA[
+			The other hub must allow links to be established.
+			Example: uhub://host:port
+		]]></description>
+		<since>0.5.0</since>
+		<ifdef>LINK_SUPPORT</ifdef>
+	</option>
 
 	<option name="max_recv_buffer" type="int" default="4096" advanced="true" >
 		<check min="1024" max="1048576" />

src/core/gen_config.c

@@ -17,6 +17,15 @@ void config_defaults(struct hub_config* config)
 	config->hub_name = hub_strdup("uhub");
 	config->hub_description = hub_strdup("no description");
 	config->redirect_addr = hub_strdup("");
+#ifdef LINK_SUPPORT
+	config->hub_link_enabled = 0;
+#endif /* LINK_SUPPORT */
+#ifdef LINK_SUPPORT
+	config->hub_link_secret = hub_strdup("");
+#endif /* LINK_SUPPORT */
+#ifdef LINK_SUPPORT
+	config->hub_link_connect = hub_strdup("");
+#endif /* LINK_SUPPORT */
 	config->max_recv_buffer = 4096;
 	config->max_send_buffer = 131072;
 	config->max_send_buffer_soft = 98304;
@@ -245,6 +254,42 @@ static int apply_config(struct hub_config* config, char* key, char* data, int li
 		return 0;
 	}
 
+#ifdef LINK_SUPPORT
+	if (!strcmp(key, "hub_link_enabled"))
+	{
+		if (!apply_boolean(key, data, &config->hub_link_enabled))
+		{
+			LOG_ERROR("Configuration parse error on line %d", line_count);
+			return -1;
+		}
+		return 0;
+	}
+#endif /* LINK_SUPPORT */
+
+#ifdef LINK_SUPPORT
+	if (!strcmp(key, "hub_link_secret"))
+	{
+		if (!apply_string(key, data, &config->hub_link_secret, (char*) ""))
+		{
+			LOG_ERROR("Configuration parse error on line %d", line_count);
+			return -1;
+		}
+		return 0;
+	}
+#endif /* LINK_SUPPORT */
+
+#ifdef LINK_SUPPORT
+	if (!strcmp(key, "hub_link_connect"))
+	{
+		if (!apply_string(key, data, &config->hub_link_connect, (char*) ""))
+		{
+			LOG_ERROR("Configuration parse error on line %d", line_count);
+			return -1;
+		}
+		return 0;
+	}
+#endif /* LINK_SUPPORT */
+
 	if (!strcmp(key, "max_recv_buffer"))
 	{
 		min = 1024;
@@ -943,6 +988,14 @@ void free_config(struct hub_config* config)
 
 	hub_free(config->redirect_addr);
 
+#ifdef LINK_SUPPORT
+	hub_free(config->hub_link_secret);
+#endif /* LINK_SUPPORT */
+
+#ifdef LINK_SUPPORT
+	hub_free(config->hub_link_connect);
+#endif /* LINK_SUPPORT */
+
 	hub_free(config->tls_require_redirect_addr);
 
 	hub_free(config->tls_certificate);
@@ -1074,6 +1127,21 @@ void dump_config(struct hub_config* config, int ignore_defaults)
 	if (!ignore_defaults || strcmp(config->redirect_addr, "") != 0)
 		fprintf(stdout, "redirect_addr = \"%s\"\n", config->redirect_addr);
 
+#ifdef LINK_SUPPORT
+	if (!ignore_defaults || config->hub_link_enabled != 0)
+		fprintf(stdout, "hub_link_enabled = %s\n", config->hub_link_enabled ? "yes" : "no");
+#endif /* LINK_SUPPORT */
+
+#ifdef LINK_SUPPORT
+	if (!ignore_defaults || strcmp(config->hub_link_secret, "") != 0)
+		fprintf(stdout, "hub_link_secret = \"%s\"\n", config->hub_link_secret);
+#endif /* LINK_SUPPORT */
+
+#ifdef LINK_SUPPORT
+	if (!ignore_defaults || strcmp(config->hub_link_connect, "") != 0)
+		fprintf(stdout, "hub_link_connect = \"%s\"\n", config->hub_link_connect);
+#endif /* LINK_SUPPORT */
+
 	if (!ignore_defaults || config->max_recv_buffer != 4096)
 		fprintf(stdout, "max_recv_buffer = %d\n", config->max_recv_buffer);
 

src/core/gen_config.h

@@ -17,6 +17,15 @@ struct hub_config
 	char* hub_name;                        /*<<< Name of hub (default: "uhub") */
 	char* hub_description;                 /*<<< Short hub description, topic or subject. (default: "no description") */
 	char* redirect_addr;                   /*<<< A common hub redirect address. (default: "") */
+#ifdef LINK_SUPPORT
+	int   hub_link_enabled;                /*<<< Allow other hubs to link to this hub (default: 0) */
+#endif /* LINK_SUPPORT */
+#ifdef LINK_SUPPORT
+	char* hub_link_secret;                 /*<<< A secret token required to accept hub linking (default: "") */
+#endif /* LINK_SUPPORT */
+#ifdef LINK_SUPPORT
+	char* hub_link_connect;                /*<<< Connect this to hub to another hub (default: "") */
+#endif /* LINK_SUPPORT */
 	int   max_recv_buffer;                 /*<<< Max read buffer before parse, per user (default: 4096) */
 	int   max_send_buffer;                 /*<<< Max send buffer before disconnect, per user (default: 131072) */
 	int   max_send_buffer_soft;            /*<<< Max send buffer before message drops, per user (default: 98304) */

src/core/hub.c

@@ -787,6 +787,13 @@ struct hub_info* hub_start_service(struct hub_config* config)
 	}
 #endif
 
+#ifdef LINK_SUPPORT
+	if (config->hub_link_enabled)
+	{
+		LOG_INFO("Hub linking support enabled");
+	}
+#endif
+
 	hub->config = config;
 	hub->users = NULL;
 
@@ -834,6 +841,15 @@ struct hub_info* hub_start_service(struct hub_config* config)
 
 	// Start the hub command sub-system
 	hub->commands = command_initialize(hub);
+
+#ifdef LINK_SUPPORT
+	if (*config->hub_link_connect)
+	{
+		link_connect_uri(hub, config->hub_link_connect);
+	}
+#endif
+
+
 	return hub;
 }
 
@@ -897,23 +913,14 @@ void hub_plugins_unload(struct hub_info* hub)
 
 void hub_set_variables(struct hub_info* hub, struct acl_handle* acl)
 {
-	char* tmp;
-	char* server = adc_msg_escape(PRODUCT_STRING); /* FIXME: OOM */
-
 	hub->acl = acl;
 	hub->command_info = adc_msg_construct(ADC_CMD_IINF, 15);
 	if (hub->command_info)
 	{
 		adc_msg_add_named_argument(hub->command_info, ADC_INF_FLAG_CLIENT_TYPE, ADC_CLIENT_TYPE_HUB);
-		adc_msg_add_named_argument(hub->command_info, ADC_INF_FLAG_USER_AGENT, server);
+		adc_msg_add_named_argument_string(hub->command_info, ADC_INF_FLAG_USER_AGENT, PRODUCT_STRING);
-
+		adc_msg_add_named_argument_string(hub->command_info, ADC_INF_FLAG_NICK, hub->config->hub_name);
-		tmp = adc_msg_escape(hub->config->hub_name);
+		adc_msg_add_named_argument_string(hub->command_info, ADC_INF_FLAG_DESCRIPTION, hub->config->hub_description);
-		adc_msg_add_named_argument(hub->command_info, ADC_INF_FLAG_NICK, tmp);
-		hub_free(tmp);
-
-		tmp = adc_msg_escape(hub->config->hub_description);
-		adc_msg_add_named_argument(hub->command_info, ADC_INF_FLAG_DESCRIPTION, tmp);
-		hub_free(tmp);
 	}
 
 	hub->command_support = adc_msg_construct(ADC_CMD_ISUP, 6 + strlen(ADC_PROTO_SUPPORT));
@@ -922,16 +929,14 @@ void hub_set_variables(struct hub_info* hub, struct acl_handle* acl)
 		adc_msg_add_argument(hub->command_support, ADC_PROTO_SUPPORT);
 	}
 
-	hub->command_banner = adc_msg_construct(ADC_CMD_ISTA, 100 + strlen(server));
+	hub->command_banner = adc_msg_construct(ADC_CMD_ISTA, 100 + adc_msg_escape_length(PRODUCT_STRING));
 	if (hub->command_banner)
 	{
-		if (hub->config->show_banner_sys_info)
-			tmp = adc_msg_escape("Powered by " PRODUCT_STRING " on " OPSYS "/" CPUINFO);
-		else
-			tmp = adc_msg_escape("Powered by " PRODUCT_STRING);
 		adc_msg_add_argument(hub->command_banner, "000");
-		adc_msg_add_argument(hub->command_banner, tmp);
+		if (hub->config->show_banner_sys_info)
-		hub_free(tmp);
+			adc_msg_add_argument_string(hub->command_banner, "Powered by " PRODUCT_STRING " on " OPSYS "/" CPUINFO);
+		else
+			adc_msg_add_argument_string(hub->command_banner, "Powered by " PRODUCT_STRING);
 	}
 
 	if (hub_plugins_load(hub) < 0)
@@ -942,7 +947,6 @@ void hub_set_variables(struct hub_info* hub, struct acl_handle* acl)
 	else
 
 	hub->status = (hub->config->hub_enabled ? hub_status_running : hub_status_disabled);
-	hub_free(server);
 }
 
 

src/core/hub.h

@@ -115,6 +115,10 @@ struct hub_info
 	struct command_base* commands;       /* Hub command handler */
 	struct uhub_plugins* plugins;        /* Plug-ins loaded for this hub instance. */
 
+#ifdef LINK_SUPPORT
+	struct linked_list* hub_links;       /* Other hubs linked to this hub */
+#endif
+
 #ifdef SSL_SUPPORT
 	struct ssl_context_handle* ctx;
 #endif /*  SSL_SUPPORT */

src/core/ioqueue.c

@@ -49,6 +49,34 @@ void ioq_recv_destroy(struct ioq_recv* q)
 	}
 }
 
+#define IOQ_RECV_FLAGS_PREALLOC 1
+#define IOQ_RECV_FLAGS_FULL 2
+
+enum ioq_recv_status ioq_recv_read(struct ioq_recv* q, struct net_connection* con)
+{
+	static char buf[MAX_RECV_BUF];
+	size_t buf_size = ioq_recv_get(q, buf, MAX_RECV_BUF);
+	ssize_t size;
+
+	if (buf_size >= MAX_RECV_BUF)
+		return ioq_recv_full;
+
+	size = net_con_recv(con, buf + buf_size, MAX_RECV_BUF - buf_size);
+
+	if (size > 0)
+		buf_size += size;
+	if (size < 0)
+		return ioq_recv_error;
+	if (size == 0)
+		return ioq_recv_later;
+
+	ioq_recv_set(q, buf, buf_size);
+	return ioq_recv_ok;
+}
+
+
+
+
 size_t ioq_recv_get(struct ioq_recv* q, void* buf, size_t bufsize)
 {
 	uhub_assert(bufsize >= q->size);
@@ -88,6 +116,21 @@ size_t ioq_recv_set(struct ioq_recv* q, void* buf, size_t bufsize)
 }
 
 
+int ioq_recv_consume(struct ioq_recv* q, size_t bytes)
+{
+	size_t newsize;
+	void* ptr;
+
+	if (!q || bytes > q->size) return 0;
+
+	newsize = (q->size - bytes);
+	memmove(q->buf, q->buf + bytes, newsize);
+	ptr = hub_realloc(q->buf, newsize);
+	q->buf = ptr;
+	q->size = newsize;
+	return 1;
+}
+
 struct ioq_send* ioq_send_create()
 {
 	struct ioq_send* q = hub_malloc_zero(sizeof(struct ioq_send));

src/core/ioqueue.h

@@ -39,6 +39,7 @@ struct ioq_recv
 {
 	char* buf;
 	size_t size;
+	// int flags;
 };
 
 /**
@@ -102,5 +103,26 @@ extern size_t ioq_recv_set(struct ioq_recv*, void* buf, size_t bufsize);
 extern int ioq_recv_is_empty(struct ioq_recv* buf);
 
 
+enum ioq_recv_status
+{
+	ioq_recv_ok = 0,    // read data OK
+	ioq_recv_later = 1, // all OK, but call again later (no change)
+	ioq_recv_full  = 2, // all OK, but the buffer is full
+	ioq_recv_error = 3, // error (connection is not working)
+};
+
+/**
+ * Receive from connection into buffer.
+ */
+extern enum ioq_recv_status ioq_recv_read(struct ioq_recv* q, struct net_connection* con);
+
+/**
+ * Consume 'bytes' bytes.
+ * 'bytes' must be <= q->size
+ *
+ * @return 1 on success, or 0 on error (only if q == NULL or bytes is > q->size).
+ */
+extern int ioq_recv_consume(struct ioq_recv* q, size_t bytes);
+
 
 #endif /* HAVE_UHUB_IO_QUEUE_H */

src/core/link.c

@@ -0,0 +1,508 @@
+/*
+ * uhub - A tiny ADC p2p connection hub
+ * Copyright (C) 2007-2013, Jan Vidar Krey
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "uhub.h"
+
+#ifdef LINK_SUPPORT
+static int link_send_support(struct hub_link* link);
+
+static void link_net_event(struct net_connection* con, int event, void *arg)
+{
+	LOG_INFO("link_net_event(), event=%d", event);
+	struct hub_link* link = (struct hub_link*) arg;
+	struct hub_info* hub = link->hub;
+	int ret = 0;
+
+	if (event == NET_EVENT_TIMEOUT)
+	{
+		LOG_DEBUG("Hub link timeout!");
+	}
+
+	if (event & NET_EVENT_READ)
+	{
+		ret = link_handle_read(link);
+		if (ret < 0)
+		{
+			link_disconnect(link);
+			return;
+		}
+	}
+
+	if (event & NET_EVENT_WRITE)
+	{
+		ret = link_handle_write(link);
+		if (ret < 0)
+		{
+			link_disconnect(link);
+			return;
+		}
+	}
+}
+
+void link_disconnect(struct hub_link* link)
+{
+	if (link->connection)
+		net_con_close(link->connection);
+	link->connection = NULL;
+
+	ioq_send_destroy(link->send_queue);
+	ioq_recv_destroy(link->recv_queue);
+	link->send_queue = NULL;
+	link->recv_queue = NULL;
+
+	// FIXME: Notify hub and disconnect users!
+
+	hub_free(link);
+}
+
+static struct hub_link* link_create_internal(struct hub_info* hub)
+{
+	struct hub_link* link = NULL;
+
+	LOG_DEBUG("link_create_internal(), hub=%p");
+	link = (struct hub_link*) hub_malloc_zero(sizeof(struct hub_link));
+	if (link == NULL)
+		return NULL; /* OOM */
+
+	link->send_queue = ioq_send_create();
+	link->recv_queue = ioq_recv_create();
+
+	link->hub = hub;
+	link->state = state_protocol;
+	return link;
+}
+
+
+struct hub_link* link_create(struct hub_info* hub, struct net_connection* con, struct ip_addr_encap* addr)
+{
+	struct hub_link* link = link_create_internal(hub);
+	link->connection = con;
+	net_con_reinitialize(link->connection, link_net_event, link, NET_EVENT_READ);
+	link->mode = link_mode_server;
+	return link;
+}
+
+static void link_connect_callback(struct net_connect_handle* handle, enum net_connect_status status, struct net_connection* con, void* ptr)
+{
+	struct hub_link* link = (struct hub_link*) ptr;
+	link->connect_job = NULL;
+
+	LOG_DEBUG("link_connect_callback()");
+
+	switch (status)
+	{
+		case net_connect_status_ok:
+			link->connection = con;
+			net_con_reinitialize(link->connection, link_net_event, link, NET_EVENT_READ);
+			// FIXME: send handshake here
+			link_send_support(link);
+			break;
+
+		case net_connect_status_host_not_found:
+		case net_connect_status_no_address:
+		case net_connect_status_dns_error:
+		case net_connect_status_refused:
+		case net_connect_status_unreachable:
+		case net_connect_status_timeout:
+		case net_connect_status_socket_error:
+			// FIXME: Unable to connect - start timer and re-try connection establishment!
+			break;
+	}
+}
+
+struct link_address
+{
+	char host[256];
+	uint16_t port;
+};
+
+static int link_parse_address(const char* arg, struct link_address* addr)
+{
+	int port;
+	char* split;
+
+	memset(addr, 0, sizeof(struct link_address));
+
+	/* Split hostname and port (if possible) */
+	split = strrchr(arg, ':');
+	if (split == 0 || strlen(split) < 2 || strlen(split) > 6)
+		return 0;
+
+	/* Ensure port number is valid */
+	port = strtol(split+1, NULL, 10);
+	if (port <= 0 || port > 65535)
+		return 0;
+
+	memcpy(addr->host, arg, &split[0] - &arg[0]);
+	addr->port = port;
+	return 1;
+}
+
+
+struct hub_link* link_connect_uri(struct hub_info* hub, const char* address)
+{
+	struct link_address link_address;
+	if (!link_parse_address(address, &link_address))
+	{
+		LOG_INFO("Invalid master hub link address");
+		return NULL;
+	}
+
+	return link_connect(hub, link_address.host, link_address.port);
+}
+
+
+struct hub_link* link_connect(struct hub_info* hub, const char* address, uint16_t port)
+{
+	struct hub_link* link = link_create_internal(hub);
+
+	LOG_DEBUG("Connecting to master link at %s:%d...", address, port);
+
+	link->mode = link_mode_client;
+	link->connect_job = net_con_connect(address, port, link_connect_callback, link);
+	if (!link->connect_job)
+	{
+		// FIXME: Immediate failure!
+		LOG_DEBUG("Error connecting to master hub link.");
+		link_disconnect(link);
+		return NULL;
+	}
+
+	return link;
+}
+
+static int link_net_io_want_read(struct hub_link* link)
+{
+	net_con_update(link->connection, NET_EVENT_READ);
+}
+
+static int link_net_io_want_write(struct hub_link* link)
+{
+	net_con_update(link->connection, NET_EVENT_READ | NET_EVENT_WRITE);
+}
+
+
+int link_handle_write(struct hub_link* link)
+{
+	int ret = 0;
+	while (ioq_send_get_bytes(link->send_queue))
+	{
+		ret = ioq_send_send(link->send_queue, link->connection);
+		if (ret <= 0)
+			break;
+	}
+
+	if (ret < 0)
+		return -1; // FIXME! Extract socket error!
+
+	if (ioq_send_get_bytes(link->send_queue))
+		link_net_io_want_write(link);
+	else
+		link_net_io_want_read(link);
+	return 0;
+}
+
+
+int link_send_message(struct hub_link* link, struct adc_message* msg)
+{
+#ifdef DEBUG_SENDQ
+	char* data = strndup(msg->cache, msg->length-1);
+	LOG_PROTO("[link] send %p: \"%s\"", link, data);
+	free(data);
+#endif
+
+	if (!link->connection)
+		return -1;
+
+	uhub_assert(msg->cache && *msg->cache);
+
+	if (ioq_send_is_empty(link->send_queue) /*&& !user_flag_get(user, flag_pipeline)*/)
+	{
+		/* Perform oportunistic write */
+		ioq_send_add(link->send_queue, msg);
+		link_handle_write(link);
+	}
+	else
+	{
+// 		if (check_send_queue(hub, user, msg) >= 0)
+// 		{
+			ioq_send_add(link->send_queue, msg);
+// 			if (!user_flag_get(user, flag_pipeline))
+			link_net_io_want_write(link);
+	}
+	return 0;
+}
+
+static int link_send_support(struct hub_link* link)
+{
+	int ret;
+	struct adc_message* msg = adc_msg_construct(ADC_CMD_LSUP, 6 + strlen(ADC_PROTO_LINK_SUPPORT));
+	adc_msg_add_argument(msg, ADC_PROTO_LINK_SUPPORT);
+	ret = link_send_message(link, msg);
+	adc_msg_free(msg);
+	return ret;
+}
+
+static int link_send_welcome(struct hub_link* link)
+{
+	int ret;
+	struct adc_message* info = adc_msg_construct(ADC_CMD_LINF, 128);
+
+	if (!info)
+		return -1;
+
+	adc_msg_add_named_argument(info, ADC_INF_FLAG_CLIENT_TYPE, ADC_CLIENT_TYPE_HUB);
+	adc_msg_add_named_argument_string(info, ADC_INF_FLAG_USER_AGENT, PRODUCT_STRING);
+	adc_msg_add_named_argument_string(info, ADC_INF_FLAG_NICK, link->hub->config->hub_name);
+	adc_msg_add_named_argument_string(info, ADC_INF_FLAG_DESCRIPTION, link->hub->config->hub_description);
+
+	ret = link_send_message(link, info);
+
+	link->state = state_normal;
+}
+
+static int link_send_auth_response(struct hub_link* link, const char* challenge)
+{
+	int ret;
+	struct adc_message* msg = adc_msg_construct(ADC_CMD_LPAS, 128);
+
+	// FIXME: Solve challenge.
+
+	ret = link_send_message(link, msg);
+	adc_msg_free(msg);
+	return ret;
+}
+
+static int link_send_auth_request(struct hub_link* link)
+{
+	int ret;
+	struct adc_message* msg = adc_msg_construct(ADC_CMD_LGPA, 128);
+
+	// FIXME: Create challenge.
+	char buf[64];
+	uint64_t tiger_res[3];
+	static char tiger_buf[MAX_CID_LEN+1];
+
+	LOG_DEBUG("link_send_auth_request");
+
+	// FIXME: Generate a better nonce scheme.
+	snprintf(buf, 64, "%p%d", link, (int) net_con_get_sd(link->connection));
+
+	tiger((uint64_t*) buf, strlen(buf), (uint64_t*) tiger_res);
+	base32_encode((unsigned char*) tiger_res, TIGERSIZE, tiger_buf);
+	tiger_buf[MAX_CID_LEN] = 0;
+
+	// Add nonce to message
+	adc_msg_add_argument(msg, (const char*) tiger_buf);
+	ret = link_send_message(link, msg);
+	adc_msg_free(msg);
+	return ret;
+}
+
+static int link_handle_support(struct hub_link* link, struct adc_message* msg)
+{
+	int ret = 0;
+
+	LOG_DEBUG("link_handle_support");
+
+	if (link->mode == link_mode_server)
+	{
+		if (link->state == state_protocol)
+		{
+			ret = link_send_support(link);
+			if (ret == 0)
+				ret = link_send_auth_request(link);
+			link->state = state_verify;
+		}
+	}
+	return ret;
+}
+
+static int link_handle_auth_request(struct hub_link* link, struct adc_message* msg)
+{
+	char* challenge;
+	int ret = -1;
+
+	LOG_DEBUG("link_handle_auth_request");
+
+	if (link->state == state_verify)
+		return -1;
+
+	if (link->mode == link_mode_client)
+	{
+		challenge = adc_msg_get_argument(msg, 0);
+		ret = link_send_auth_response(link, challenge);
+		hub_free(challenge);
+	}
+	return ret;
+}
+
+static int link_handle_auth_response(struct hub_link* link, struct adc_message* msg)
+{
+
+	LOG_DEBUG("link_handle_auth_response. link_state=%d", (int) link->state);
+
+	if (link->state != state_verify)
+		return -1;
+
+	LOG_DEBUG("State is not verify!");
+
+	if (link->mode == link_mode_server)
+	{
+		// Check authentication data
+		// FIXME: Can involve plug-ins at this point.
+		return link_send_welcome(link);
+	}
+	else
+	{
+		LOG_DEBUG("Ignoring auth response - We're client mode!");
+	}
+
+	return -1;
+}
+
+static int link_handle_link_info(struct hub_link* link, struct adc_message* msg)
+{
+	LOG_DEBUG("link_handle_link_info");
+	return 0;
+}
+
+static int link_handle_status(struct hub_link* link, struct adc_message* msg)
+{
+	LOG_DEBUG("link_handle_status");
+	return -1;
+}
+
+static int link_handle_message(struct hub_link* link, const char* message, size_t length)
+{
+	int ret = 0;
+	struct adc_message* cmd = 0;
+
+	LOG_INFO("link_handle_message(): %s (%d)", message, (int) length);
+
+	// FIXME: is this needed?
+	if (link->state == state_cleanup || link->state == state_disconnected)
+		return -1;
+
+	cmd = adc_msg_parse(message, length);
+	if (!cmd)
+	{
+		LOG_DEBUG("Unable to parse hub-link message");
+		return -1;
+	}
+
+	// if (
+
+	switch (cmd->cmd)
+	{
+		case ADC_CMD_LSUP:
+			ret = link_handle_support(link, cmd);
+			break;
+
+		case ADC_CMD_LPAS:
+			ret = link_handle_auth_response(link, cmd);
+			break;
+
+		case ADC_CMD_LGPA:
+			ret = link_handle_auth_request(link, cmd);
+			break;
+
+		case ADC_CMD_LINF:
+			ret = link_handle_link_info(link, cmd);
+			break;
+
+		case ADC_CMD_LSTA:
+			ret = link_handle_status(link, cmd);
+			break;
+	}
+
+	adc_msg_free(cmd);
+	return ret;
+}
+
+
+static int link_read_message(struct hub_link* link)
+{
+	char* lastPos = 0;
+	char* pos = 0;
+	char* start = link->recv_queue->buf;
+	size_t remaining = link->recv_queue->size;
+
+	while ((pos = memchr(start, '\n', remaining)))
+	{
+		lastPos = pos+1;
+		pos[0] = '\0';
+
+		if (link->flags & 1)
+		{
+			 /* FIXME Unset maxbuf flag */
+			link->flags = 0;
+		}
+		else
+		{
+			if (link_handle_message(link, start, (pos - start)) == -1)
+			{
+				return -1;
+			}
+		}
+
+		pos[0] = '\n'; /* FIXME: not needed */
+		pos ++;
+		remaining -= (pos - start);
+		start = pos;
+	}
+
+	ioq_recv_consume(link->recv_queue, (start - link->recv_queue->buf));
+	return 0;
+}
+
+int link_handle_read(struct hub_link* link)
+{
+	int ret = 0;
+	while (1)
+	{
+		switch (ioq_recv_read(link->recv_queue, link->connection))
+		{
+			case ioq_recv_ok:
+				if (link_read_message(link) < 0)
+				{
+					// FIXME: propagate protocol error?
+					return -1;
+				}
+				// Parse messages then call again
+				break;
+				
+			case ioq_recv_later:
+				return 0;
+
+			case ioq_recv_full:
+				link->flags = 1; // FIXME: MAXBUF
+				ioq_recv_set(link->recv_queue, 0, 0);
+				break;
+
+			case ioq_recv_error:
+				return -1; // FIXME: it would be good to signal type of socket error
+		}
+	}
+
+	return 0;
+}
+
+
+#endif /* LINK_SUPPORT */

src/core/link.h

@@ -0,0 +1,70 @@
+/*
+ * uhub - A tiny ADC p2p connection hub
+ * Copyright (C) 2007-2013, Jan Vidar Krey
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef HAVE_UHUB_LINK_H
+#define HAVE_UHUB_LINK_H
+
+#ifdef LINK_SUPPORT
+
+struct hub_link
+{
+	char name[MAX_NICK_LEN+1];         /** The name of the linked hub */
+	char user_agent[MAX_UA_LEN+1];     /** The user agent of the linked hub */
+	char address[256];                 /** The official address of the linked hub */
+	enum link_mode { link_mode_client, link_mode_server } mode;
+	enum user_state state;
+	struct ioq_send* send_queue;
+	struct ioq_recv* recv_queue;
+	struct net_connection* connection; /** Connection data */
+	struct net_connect_handle* connect_job; /** Only used when establishing a connection in client mode */
+	struct hub_info* hub;
+	int flags;
+};
+
+/**
+ * Create a link from an accepted connection (act as a link server).
+ */
+extern struct hub_link* link_create(struct hub_info* hub, struct net_connection* con, struct ip_addr_encap* addr);
+
+/**
+ * Connect this hub to an upstream server (act as a link client).
+ */
+extern struct hub_link* link_connect(struct hub_info* hub, const char* address, uint16_t port);
+extern struct hub_link* link_connect_uri(struct hub_info* hub, const char* address);
+
+/**
+ * Disconnect a link connection.
+ */
+extern void link_disconnect(struct hub_link*);
+
+/**
+ * Read from link connection and process messages.
+ * @return 0 on success, and a negative value otherwise
+ */
+extern int link_handle_read(struct hub_link* link);
+
+/**
+ * Write queued messages to the link.
+ * @return 0 on success, and a negative value otherwise.
+ */
+extern int link_handle_write(struct hub_link* link);
+
+#endif // LINK_SUPPORT
+
+#endif /* HAVE_UHUB_LINK_H */

src/core/main.c

@@ -125,6 +125,10 @@ int main_loop()
 			hub_set_log_verbosity(arg_verbose);
 		}
 
+#ifdef DEBUG
+		LOG_INFO("Debug messages enabled");
+#endif
+	
 		if (read_config(arg_config, &configuration, !arg_have_config) == -1)
 			return -1;
 

src/core/probe.c

@@ -71,6 +71,17 @@ static void probe_net_event(struct net_connection* con, int events, void *arg)
 				probe_destroy(probe);
 				return;
 			}
+#ifdef LINK_SUPPORT
+			else if (probe->hub->config->hub_link_enabled && memcmp(probe_recvbuf, "LSUP", 4) == 0)
+			{
+				if (link_create(probe->hub, probe->connection, &probe->addr))
+				{
+					probe->connection = 0;
+				}
+				probe_destroy(probe);
+				return;
+			}
+#endif /* LINK_SUPPORT */
 #ifdef SSL_SUPPORT
 			else if (bytes >= 11 &&
 				probe_recvbuf[0] == 22 && 

src/core/route.c

@@ -99,7 +99,7 @@ int route_to_user(struct hub_info* hub, struct hub_user* user, struct adc_messag
 {
 #ifdef DEBUG_SENDQ
 	char* data = strndup(msg->cache, msg->length-1);
-	LOG_PROTO("send %s: \"%s\"", sid_to_string(user->id.sid), data);
+	LOG_PROTO("[user] send %s: \"%s\"", sid_to_string(user->id.sid), data);
 	free(data);
 #endif
 

src/uhub.h

@@ -94,6 +94,7 @@ extern "C" {
 #include "core/commands.h"
 #include "core/inf.h"
 #include "core/hubevent.h"
+#include "core/link.h"
 #include "core/plugincallback.h"
 #include "core/plugininvoke.h"
 #include "core/pluginloader.h"