From eee2636582ebfaae86e5d6262177c01f7e9e5778 Mon Sep 17 00:00:00 2001
From: Jan Vidar Krey <janvidar@extatic.org>
Date: Mon, 9 Jan 2012 19:54:03 +0100
Subject: [PATCH] Added a chat only hub plugin that disables searching and
 connection setup.

This also deprecates the built-in chat_only configuration option.
If you need this functionality, then load the mod_chat_only plugin (if it is loaded then only operators
are able to search, connect, etc).
---
 GNUmakefile                  |   8 +-
 src/adc/adcconst.h           |   5 ++
 src/core/config.xml          |   8 --
 src/core/gen_config.c        |  14 ---
 src/core/gen_config.h        |   1 -
 src/core/hub.c               |  26 ++++--
 src/core/plugincallback.c    |  15 ++++
 src/core/plugininvoke.c      |   7 ++
 src/core/plugininvoke.h      |   1 +
 src/plugin_api/handle.h      |   4 +
 src/plugin_api/message_api.h |   5 ++
 src/plugins/mod_chat_only.c  | 163 +++++++++++++++++++++++++++++++++++
 12 files changed, 226 insertions(+), 31 deletions(-)
 create mode 100644 src/plugins/mod_chat_only.c

diff --git a/GNUmakefile b/GNUmakefile
index 3c9bd6d..68f0416 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -229,6 +229,9 @@ plugin_auth_sqlite_LIBS    := -lsqlite3
 plugin_chat_history_SOURCE := src/plugins/mod_chat_history.c
 plugin_chat_history_TARGET := mod_chat_history.so
 
+plugin_chat_only_SOURCE := src/plugins/mod_chat_only.c
+plugin_chat_only_TARGET := mod_chat_only.so
+
 # Source to objects
 libuhub_OBJECTS       := $(libuhub_SOURCES:.c=.o)
 libutils_OBJECTS      := $(libutils_SOURCES:.c=.o)
@@ -240,7 +243,7 @@ uhub-passwd_OBJECTS   := $(uhub-passwd_SOURCES:.c=.o)
 adcrush_OBJECTS       := $(adcrush_SOURCES:.c=.o)
 admin_OBJECTS         := $(admin_SOURCES:.c=.o)
 
-all_plugins     := $(plugin_example_TARGET) $(plugin_logging_TARGET) $(plugin_auth_TARGET) $(plugin_auth_sqlite_TARGET) $(plugin_welcome_TARGET) $(plugin_chat_history_TARGET)
+all_plugins     := $(plugin_example_TARGET) $(plugin_logging_TARGET) $(plugin_auth_TARGET) $(plugin_auth_sqlite_TARGET) $(plugin_welcome_TARGET) $(plugin_chat_history_TARGET) $(plugin_chat_only_TARGET)
 all_OBJECTS     := $(libuhub_OBJECTS) $(uhub_OBJECTS) $(libutils_OBJECTS) $(adcrush_OBJECTS) $(autotest_OBJECTS) $(admin_OBJECTS) $(libadc_common_OBJECTS) $(libadc_client_OBJECTS)
 all_OBJECTS     += $(all_plugins)
 
@@ -280,6 +283,9 @@ $(plugin_logging_TARGET): $(plugin_logging_SOURCES) $(libutils_OBJECTS) $(libadc
 $(plugin_chat_history_TARGET): $(plugin_chat_history_SOURCE) $(libutils_OBJECTS)
 	$(MSG_CC) $(CC) -shared -fPIC -o $@ $^ $(CFLAGS)
 
+$(plugin_chat_only_TARGET): $(plugin_chat_only_SOURCE) $(libutils_OBJECTS)
+	$(MSG_CC) $(CC) -shared -fPIC -o $@ $^ $(CFLAGS)
+
 $(plugin_welcome_TARGET): $(plugin_welcome_SOURCES) $(libutils_OBJECTS)
 	$(MSG_CC) $(CC) -shared -fPIC -o $@ $^ $(CFLAGS)
 
diff --git a/src/adc/adcconst.h b/src/adc/adcconst.h
index f78db84..45e4f38 100644
--- a/src/adc/adcconst.h
+++ b/src/adc/adcconst.h
@@ -64,6 +64,11 @@ typedef uint32_t fourcc_t;
 #define ADC_CMD_FSCH FOURCC('F','S','C','H')
 #define ADC_CMD_DRES FOURCC('D','R','E','S')
 
+/* invalid search results (spam) */
+#define ADC_CMD_BRES FOURCC('B','R','E','S')
+#define ADC_CMD_ERES FOURCC('E','R','E','S')
+#define ADC_CMD_FRES FOURCC('F','R','E','S')
+
 /* connection setup */
 #define ADC_CMD_DCTM FOURCC('D','C','T','M')
 #define ADC_CMD_DRCM FOURCC('D','R','C','M')
diff --git a/src/core/config.xml b/src/core/config.xml
index 990683e..40e4932 100644
--- a/src/core/config.xml
+++ b/src/core/config.xml
@@ -126,14 +126,6 @@
 		<since>0.3.1</since>
 	</option>
 
-	<option name="chat_only" type="boolean" default="0">
-		<short>Allow chat only operation on hub</short>
-		<description><![CDATA[
-			If this is enabled the hub will refuse to relay messages for search and connection setup. This effectively makes the hub viable for chat only.
-		]]></description>
-		<since>0.1.1</since>
-	</option>
-
 	<option name="chat_is_privileged" type="boolean" default="0">
 		<short>Allow chat for operators and above only</short>
 		<description><![CDATA[
diff --git a/src/core/gen_config.c b/src/core/gen_config.c
index 58bf3e5..855f296 100644
--- a/src/core/gen_config.c
+++ b/src/core/gen_config.c
@@ -13,7 +13,6 @@ void config_defaults(struct hub_config* config)
 	config->registered_users_only = 0;
 	config->register_self = 0;
 	config->obsolete_clients = 0;
-	config->chat_only = 0;
 	config->chat_is_privileged = 0;
 	config->hub_name = hub_strdup("uhub");
 	config->hub_description = hub_strdup("no description");
@@ -203,16 +202,6 @@ static int apply_config(struct hub_config* config, char* key, char* data, int li
 		return 0;
 	}
 
-	if (!strcmp(key, "chat_only"))
-	{
-		if (!apply_boolean(key, data, &config->chat_only))
-		{
-			LOG_ERROR("Configuration parse error on line %d", line_count);
-			return -1;
-		}
-		return 0;
-	}
-
 	if (!strcmp(key, "chat_is_privileged"))
 	{
 		if (!apply_boolean(key, data, &config->chat_is_privileged))
@@ -1052,9 +1041,6 @@ void dump_config(struct hub_config* config, int ignore_defaults)
 	if (!ignore_defaults || config->obsolete_clients != 0)
 		fprintf(stdout, "obsolete_clients = %s\n", config->obsolete_clients ? "yes" : "no");
 
-	if (!ignore_defaults || config->chat_only != 0)
-		fprintf(stdout, "chat_only = %s\n", config->chat_only ? "yes" : "no");
-
 	if (!ignore_defaults || config->chat_is_privileged != 0)
 		fprintf(stdout, "chat_is_privileged = %s\n", config->chat_is_privileged ? "yes" : "no");
 
diff --git a/src/core/gen_config.h b/src/core/gen_config.h
index 7071211..b5db448 100644
--- a/src/core/gen_config.h
+++ b/src/core/gen_config.h
@@ -13,7 +13,6 @@ struct hub_config
 	int   registered_users_only;           /*<<< Allow registered users only (default: 0) */
 	int   register_self;                   /*<<< Allow users to register themselves on the hub. (default: 0) */
 	int   obsolete_clients;                /*<<< Support obsolete clients using a ADC protocol prior to 1.0 (default: 0) */
-	int   chat_only;                       /*<<< Allow chat only operation on hub (default: 0) */
 	int   chat_is_privileged;              /*<<< Allow chat for operators and above only (default: 0) */
 	char* hub_name;                        /*<<< Name of hub (default: uhub) */
 	char* hub_description;                 /*<<< Short hub description, topic or subject. (default: no description) */
diff --git a/src/core/hub.c b/src/core/hub.c
index 61e50b9..e817bf2 100644
--- a/src/core/hub.c
+++ b/src/core/hub.c
@@ -21,10 +21,6 @@
 
 struct hub_info* g_hub = 0;
 
-#define CHECK_CHAT_ONLY \
-	if (hub->config->chat_only && u->credentials < auth_cred_operator) \
-		break
-
 /* FIXME: Flood control should be done in a plugin! */
 #define CHECK_FLOOD(TYPE, WARN) \
 	if (flood_control_check(&u->flood_ ## TYPE , hub->config->flood_ctl_  ## TYPE, hub->config->flood_ctl_interval, net_get_time())) \
@@ -81,6 +77,7 @@ int hub_handle_message(struct hub_info* hub, struct hub_user* u, const char* lin
 			case ADC_CMD_EINF:
 			case ADC_CMD_FINF:
 				/* these must never be allowed for security reasons, so we ignore them. */
+				CHECK_FLOOD(extras, 1);
 				break;
 
 			case ADC_CMD_EMSG:
@@ -96,20 +93,35 @@ int hub_handle_message(struct hub_info* hub, struct hub_user* u, const char* lin
 			case ADC_CMD_ESCH:
 			case ADC_CMD_FSCH:
 				cmd->priority = -1;
-				CHECK_CHAT_ONLY;
+				if (plugin_handle_search(hub, u, cmd->cache) == st_deny)
+					break;
 				CHECK_FLOOD(search, 1);
 				ROUTE_MSG;
 
+			case ADC_CMD_FRES: // spam
+			case ADC_CMD_BRES: // spam
+			case ADC_CMD_ERES: // pointless.
+				CHECK_FLOOD(extras, 1);
+				break;
+
 			case ADC_CMD_DRES:
 				cmd->priority = -1;
-				CHECK_CHAT_ONLY;
+				if (plugin_handle_search_result(hub, u, uman_get_user_by_sid(hub, cmd->target), cmd->cache) == st_deny)
+					break;
 				/* CHECK_FLOOD(search, 0); */
 				ROUTE_MSG;
 
 			case ADC_CMD_DRCM:
+				cmd->priority = -1;
+				if (plugin_handle_revconnect(hub, u, uman_get_user_by_sid(hub, cmd->target)) == st_deny)
+					break;
+				CHECK_FLOOD(connect, 1);
+				ROUTE_MSG;
+
 			case ADC_CMD_DCTM:
 				cmd->priority = -1;
-				CHECK_CHAT_ONLY;
+				if (plugin_handle_connect(hub, u, uman_get_user_by_sid(hub, cmd->target)) == st_deny)
+					break;
 				CHECK_FLOOD(connect, 1);
 				ROUTE_MSG;
 
diff --git a/src/core/plugincallback.c b/src/core/plugincallback.c
index 373c31f..62b5c5b 100644
--- a/src/core/plugincallback.c
+++ b/src/core/plugincallback.c
@@ -92,6 +92,20 @@ static int cbfunc_send_message(struct plugin_handle* plugin, struct plugin_user*
 	return 1;
 }
 
+static int cbfunc_send_status(struct plugin_handle* plugin, struct plugin_user* user, int code, const char* message)
+{
+//	struct plugin_callback_data* data = get_callback_data(plugin);
+	char code_str[4];
+	char* buffer = adc_msg_escape(message);
+	struct adc_message* command = adc_msg_construct(ADC_CMD_ISTA, strlen(buffer) + 10);
+	snprintf(code_str, sizeof(code_str), "%03d", code);
+	adc_msg_add_argument(command, code_str);
+	adc_msg_add_argument(command, buffer);
+	route_to_user(plugin_get_hub(plugin), convert_user_type(user), command);
+	adc_msg_free(command);
+	hub_free(buffer);
+	return 1;
+}
 
 static int cbfunc_user_disconnect(struct plugin_handle* plugin, struct plugin_user* user)
 {
@@ -136,6 +150,7 @@ static int cbfunc_command_del(struct plugin_handle* plugin, struct plugin_comman
 void plugin_register_callback_functions(struct plugin_handle* handle)
 {
 	handle->hub.send_message = cbfunc_send_message;
+	handle->hub.send_status_message = cbfunc_send_status;
 	handle->hub.user_disconnect = cbfunc_user_disconnect;
 	handle->hub.command_add = cbfunc_command_add;
 	handle->hub.command_del = cbfunc_command_del;
diff --git a/src/core/plugininvoke.c b/src/core/plugininvoke.c
index 773fba0..ed31ef7 100644
--- a/src/core/plugininvoke.c
+++ b/src/core/plugininvoke.c
@@ -155,6 +155,13 @@ plugin_st plugin_handle_search(struct hub_info* hub, struct hub_user* from, cons
 	PLUGIN_INVOKE_STATUS_2(hub, on_search, user, data);
 }
 
+plugin_st plugin_handle_search_result(struct hub_info* hub, struct hub_user* from, struct hub_user* to, const char* data)
+{
+	struct plugin_user* user1 = convert_user_type(from);
+	struct plugin_user* user2 = convert_user_type(to);
+	PLUGIN_INVOKE_STATUS_3(hub, on_search_result, user1, user2, data);
+}
+
 plugin_st plugin_handle_connect(struct hub_info* hub, struct hub_user* from, struct hub_user* to)
 {
 	struct plugin_user* user1 = convert_user_type(from);
diff --git a/src/core/plugininvoke.h b/src/core/plugininvoke.h
index 1c5a391..c01e705 100644
--- a/src/core/plugininvoke.h
+++ b/src/core/plugininvoke.h
@@ -50,6 +50,7 @@ plugin_st plugin_handle_private_message(struct hub_info* hub, struct hub_user* f
 
 /* Handle searches */
 plugin_st plugin_handle_search(struct hub_info* hub, struct hub_user* user, const char* data);
+plugin_st plugin_handle_search_result(struct hub_info* hub, struct hub_user* from, struct hub_user* to, const char* data);
 
 /* Handle p2p connections */
 plugin_st plugin_handle_connect(struct hub_info* hub, struct hub_user* from, struct hub_user* to);
diff --git a/src/plugin_api/handle.h b/src/plugin_api/handle.h
index 3faded5..c7fc709 100644
--- a/src/plugin_api/handle.h
+++ b/src/plugin_api/handle.h
@@ -32,6 +32,7 @@
 typedef plugin_st (*on_chat_msg_t)(struct plugin_handle*, struct plugin_user* from, const char* message);
 typedef plugin_st (*on_private_msg_t)(struct plugin_handle*, struct plugin_user* from, struct plugin_user* to, const char* message);
 typedef plugin_st (*on_search_t)(struct plugin_handle*, struct plugin_user* from, const char* data);
+typedef plugin_st (*on_search_result_t)(struct plugin_handle*, struct plugin_user* from, struct plugin_user* to, const char* data);
 typedef plugin_st (*on_p2p_connect_t)(struct plugin_handle*, struct plugin_user* from, struct plugin_user* to);
 typedef plugin_st (*on_p2p_revconnect_t)(struct plugin_handle*, struct plugin_user* from, struct plugin_user* to);
 
@@ -89,6 +90,7 @@ struct plugin_funcs
 	on_chat_msg_t           on_chat_msg;         /* A public chat message is about to be sent (can be intercepted) */
 	on_private_msg_t        on_private_msg;      /* A public chat message is about to be sent (can be intercepted) */
 	on_search_t             on_search;           /* A search is about to be sent (can be intercepted) */
+	on_search_result_t      on_search_result;    /* A search result is about to be sent (can be intercepted) */
 	on_p2p_connect_t        on_p2p_connect;      /* A user is about to connect to another user (can be intercepted) */
 	on_p2p_revconnect_t     on_p2p_revconnect;   /* A user is about to connect to another user (can be intercepted) */
 
@@ -106,6 +108,7 @@ struct plugin_funcs
 struct plugin_command_handle;
 
 typedef int (*hfunc_send_message)(struct plugin_handle*, struct plugin_user* user, const char* message);
+typedef int (*hfunc_send_status)(struct plugin_handle*, struct plugin_user* to, int code, const char* message);
 typedef int (*hfunc_user_disconnect)(struct plugin_handle*, struct plugin_user* user);
 typedef int (*hfunc_command_add)(struct plugin_handle*, struct plugin_command_handle*);
 typedef int (*hfunc_command_del)(struct plugin_handle*, struct plugin_command_handle*);
@@ -117,6 +120,7 @@ typedef int (*hfunc_command_del)(struct plugin_handle*, struct plugin_command_ha
 struct plugin_hub_funcs
 {
 	hfunc_send_message send_message;
+	hfunc_send_status send_status_message;
 	hfunc_user_disconnect user_disconnect;
 	hfunc_command_add command_add;
 	hfunc_command_del command_del;
diff --git a/src/plugin_api/message_api.h b/src/plugin_api/message_api.h
index 628805c..8903f8f 100644
--- a/src/plugin_api/message_api.h
+++ b/src/plugin_api/message_api.h
@@ -26,4 +26,9 @@
  */
 extern int plugin_send_message(struct plugin_handle*, struct plugin_user* to, const char* message);
 
+/**
+ * Send a status message to a user.
+ */
+extern int plugin_send_status(struct plugin_handle* struct plugin_user* to, int code, const char* message);
+
 #endif /* HAVE_UHUB_PLUGIN_API_H */
diff --git a/src/plugins/mod_chat_only.c b/src/plugins/mod_chat_only.c
new file mode 100644
index 0000000..814a104
--- /dev/null
+++ b/src/plugins/mod_chat_only.c
@@ -0,0 +1,163 @@
+/*
+ * uhub - A tiny ADC p2p connection hub
+ * Copyright (C) 2007-2012, 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 "plugin_api/handle.h"
+#include "util/memory.h"
+
+enum Warnings
+{
+	WARN_SEARCH         = 0x01, ///<<< "Warn about searching."
+	WARN_CONNECT        = 0x02, ///<<< "Warn about connecting to a user"
+	WARN_EXTRA          = 0x08, ///<<< "Warn about unknown protocol data."
+};
+
+struct user_info
+{
+	sid_t sid;      // The SID of the user
+	int warnings;   // The number of denies (used to track wether or not a warning should be sent). @see enum Warnings.
+};
+
+struct chat_only_data
+{
+	size_t num_users;        // number of users tracked.
+	size_t max_users;        // max users (hard limit max 1M users due to limitations in the SID (20 bits)).
+	struct user_info* users; // array of max_users
+	int operator_override;   // operators are allowed to override these limitations.
+};
+
+static struct chat_only_data* co_initialize()
+{
+	struct chat_only_data* data = (struct chat_only_data*) hub_malloc(sizeof(struct chat_only_data));
+	data->num_users = 0;
+	data->max_users = 512;
+	data->users = hub_malloc_zero(sizeof(struct user_info) * data->max_users);
+	return data;
+}
+
+static void co_shutdown(struct chat_only_data* data)
+{
+	if (data)
+	{
+		hub_free(data->users);
+		hub_free(data);
+	}
+}
+
+static struct user_info* get_user_info(struct chat_only_data* data, sid_t sid)
+{
+	struct user_info* u;
+
+	// resize buffer if needed.
+	if (sid > data->max_users) // FIXME: >= ?
+	{
+		u = hub_malloc_zero(sizeof(struct user_info) * (sid + 1));
+		memcpy(u, data->users, data->max_users);
+		hub_free(data->users);
+		data->users = u;
+		data->max_users = sid;
+		u = NULL;
+	}
+
+	u = &data->users[sid];
+
+	// reset counters if the user was not previously known.
+	if (!u->sid)
+	{
+		u->sid = sid;
+		u->warnings = 0;
+		data->num_users++;
+	}
+	return u;
+}
+
+static plugin_st on_search_result(struct plugin_handle* plugin, struct plugin_user* from, struct plugin_user* to, const char* search_data)
+{
+	return st_deny;
+}
+
+static plugin_st on_search(struct plugin_handle* plugin, struct plugin_user* user, const char* search_data)
+{
+	struct chat_only_data* data = (struct chat_only_data*) plugin->ptr;
+	struct user_info* info = get_user_info(data, user->sid);
+
+	if (user->credentials >= auth_cred_operator && data->operator_override)
+		return st_allow;
+
+	if (!(info->warnings & WARN_SEARCH))
+	{
+		plugin->hub.send_status_message(plugin, user, 000, "Searching is disabled. This is a chat only hub.");
+		info->warnings |= WARN_SEARCH;
+	}
+	return st_deny;
+}
+
+static plugin_st on_p2p_connect(struct plugin_handle* plugin, struct plugin_user* from, struct plugin_user* to)
+{
+	struct chat_only_data* data = (struct chat_only_data*) plugin->ptr;
+	struct user_info* info = get_user_info(data, from->sid);
+
+	if (from->credentials >= auth_cred_operator && data->operator_override)
+		return st_allow;
+
+	if (!(info->warnings & WARN_CONNECT))
+	{
+		plugin->hub.send_status_message(plugin, from, 000, "Connection setup denied. This is a chat only hub.");
+		info->warnings |= WARN_CONNECT;
+	}
+	return st_deny;
+}
+
+static void on_user_login(struct plugin_handle* plugin, struct plugin_user* user)
+{
+	struct chat_only_data* data = (struct chat_only_data*) plugin->ptr;
+	/*struct user_info* info = */
+	get_user_info(data, user->sid);
+}
+
+static void on_user_logout(struct plugin_handle* plugin, struct plugin_user* user, const char* reason)
+{
+	struct chat_only_data* data = (struct chat_only_data*) plugin->ptr;
+	struct user_info* info = get_user_info(data, user->sid);
+	if (info->sid)
+		data->num_users--;
+	info->warnings = 0;
+	info->sid = 0;
+}
+
+int plugin_register(struct plugin_handle* plugin, const char* config)
+{
+	PLUGIN_INITIALIZE(plugin, "Chat only hub", "1.0", "Disables connection setup, search and results.");
+	plugin->ptr = co_initialize();
+
+	plugin->funcs.on_search = on_search;
+	plugin->funcs.on_search_result = on_search_result;
+	plugin->funcs.on_p2p_connect = on_p2p_connect;
+	plugin->funcs.on_p2p_revconnect = on_p2p_connect;
+	plugin->funcs.on_user_login = on_user_login;
+	plugin->funcs.on_user_logout = on_user_logout;
+
+	return 0;
+}
+
+int plugin_unregister(struct plugin_handle* plugin)
+{
+	co_shutdown((struct chat_only_data*) plugin->ptr);
+	return 0;
+}
+