subnet.conf overhaul

The subnet.conf system has been rewritten to offer greater flexibility,
and to fix some issues that appeared with 838321a36c79e71117320154c9b611c99e93af03.

It is now possible to enter, separately, LAN subnets:

- `lan_subnets`: This is essentially the same feature present in the old
  subnet.conf. Each entry in this list defines a (LAN, private) subnet
  the server is in. Clients connecting from the same subnet, will be
  redirected to the LAN IP rather than the default public IP. The format
  has been simplified, and it only requires one IP and one subnet mask (as
  opposed to a character and a map server IP).
- `allowed`: Allowed IPs are IP ranges a server (char to login or map to
  char) can connect from. Any attempt to connect as a server from an IP
  not included here, will fail. For convenience, a wildcard range
  (matching all possible IP addresses) has been provided
  (`0.0.0.0:0.0.0.0`), but it is very advisable to edit it to a more
  restrictive set.
- `trusted`: Trusted IPs are IP ranges excluded from the IPban checks.
  This may be useful, for example, to exclude the server's own IP from
  ipbans, in case of false positives. Any IP ranges added to this list are
  also implicitly included in the allowed IP ranges.

6 files changed, 265 insertions, 177 deletions

diff --git a/src/char/char.c b/src/char/char.c
index b6ce70985..c731c89ee 100644
--- a/src/char/char.c
+++ b/src/char/char.c
@@ -121,14 +121,6 @@ int log_inter = 1; // logging inter or not [devil]
 
 int char_aegis_delete = 0; // Verify if char is in guild/party or char and reacts as Aegis does (doesn't allow deletion), see chr->delete2_req for more information
 
-// Advanced subnet check [LuzZza]
-struct s_subnet {
-	uint32 mask;
-	uint32 char_ip;
-	uint32 map_ip;
-} subnet[16];
-int subnet_count = 0;
-
 int max_connect_user = -1;
 int gm_allow_group = -1;
 int autosave_interval = DEFAULT_AUTOSAVE_INTERVAL;
@@ -4171,20 +4163,22 @@ static int char_mapif_init(int fd)
 	return inter->mapif_init(fd);
 }
 
-//--------------------------------------------
-// Test to know if an IP come from LAN or WAN.
-//--------------------------------------------
-int char_lan_subnetcheck(uint32 ip)
+/**
+ * Checks whether the given IP comes from LAN or WAN.
+ *
+ * @param ip IP address to check.
+ * @retval 0 if it is a WAN IP.
+ * @return the appropriate LAN server address to send, if it is a LAN IP.
+ */
+uint32 char_lan_subnet_check(uint32 ip)
 {
-	int i;
-	ARR_FIND( 0, subnet_count, i, (subnet[i].char_ip & subnet[i].mask) == (ip & subnet[i].mask) );
-	if( i < subnet_count ) {
-		ShowInfo("Subnet check [%u.%u.%u.%u]: Matches "CL_CYAN"%u.%u.%u.%u/%u.%u.%u.%u"CL_RESET"\n", CONVIP(ip), CONVIP(subnet[i].char_ip & subnet[i].mask), CONVIP(subnet[i].mask));
-		return subnet[i].map_ip;
-	} else {
-		ShowInfo("Subnet check [%u.%u.%u.%u]: "CL_CYAN"WAN"CL_RESET"\n", CONVIP(ip));
-		return 0;
+	struct s_subnet lan = {0};
+	if (sockt->lan_subnet_check(ip, &lan)) {
+		ShowInfo("Subnet check [%u.%u.%u.%u]: Matches "CL_CYAN"%u.%u.%u.%u/%u.%u.%u.%u"CL_RESET"\n", CONVIP(ip), CONVIP(lan.ip & lan.mask), CONVIP(lan.mask));
+		return lan.ip;
 	}
+	ShowInfo("Subnet check [%u.%u.%u.%u]: "CL_CYAN"WAN"CL_RESET"\n", CONVIP(ip));
+	return 0;
 }
 
 
@@ -4662,7 +4656,7 @@ void char_parse_char_select(int fd, struct char_session_data* sd, uint32 ipl)
 		return;
 	}
 
-	subnet_map_ip = chr->lan_subnetcheck(ipl); // Advanced subnet check [LuzZza]
+	subnet_map_ip = chr->lan_subnet_check(ipl);
 	//Send player to map
 	chr->send_map_info(fd, i, subnet_map_ip, cd);
 
@@ -4971,7 +4965,7 @@ void char_parse_char_login_map_server(int fd, uint32 ipl)
 		i == ARRAYLENGTH(chr->server) ||
 		strcmp(l_user, chr->userid) != 0 ||
 		strcmp(l_pass, chr->passwd) != 0 ||
-		!chr->lan_subnetcheck(ipl))
+		!sockt->allowed_ip_check(ipl))
 	{
 		chr->login_map_server_ack(fd, 3); // Failure
 	} else {
@@ -5449,60 +5443,6 @@ static int char_online_data_cleanup(int tid, int64 tick, int id, intptr_t data)
 	return 0;
 }
 
-//----------------------------------
-// Reading LAN Support configuration
-// Rewrote: Advanced subnet check [LuzZza]
-//----------------------------------
-int char_lan_config_read(const char *lancfgName)
-{
-	FILE *fp;
-	int line_num = 0;
-	char line[1024], w1[64], w2[64], w3[64], w4[64];
-
-	if((fp = fopen(lancfgName, "r")) == NULL) {
-		ShowWarning("LAN Support configuration file is not found: %s\n", lancfgName);
-		return 1;
-	}
-
-	while(fgets(line, sizeof(line), fp)) {
-		line_num++;
-		if ((line[0] == '/' && line[1] == '/') || line[0] == '\n' || line[1] == '\n')
-			continue;
-
-		if (sscanf(line,"%63[^:]: %63[^:]:%63[^:]:%63[^\r\n]", w1, w2, w3, w4) != 4) {
-
-			ShowWarning("Error syntax of configuration file %s in line %d.\n", lancfgName, line_num);
-			continue;
-		}
-
-		remove_control_chars(w1);
-		remove_control_chars(w2);
-		remove_control_chars(w3);
-		remove_control_chars(w4);
-
-		if( strcmpi(w1, "subnet") == 0 )
-		{
-			subnet[subnet_count].mask = str2ip(w2);
-			subnet[subnet_count].char_ip = str2ip(w3);
-			subnet[subnet_count].map_ip = str2ip(w4);
-
-			if( (subnet[subnet_count].char_ip & subnet[subnet_count].mask) != (subnet[subnet_count].map_ip & subnet[subnet_count].mask) )
-			{
-				ShowError("%s: Configuration Error: The char server (%s) and map server (%s) belong to different subnetworks!\n", lancfgName, w3, w4);
-				continue;
-			}
-
-			subnet_count++;
-		}
-	}
-
-	if( subnet_count > 1 ) /* only useful if there is more than 1 */
-		ShowStatus("Read information about %d subnetworks.\n", subnet_count);
-
-	fclose(fp);
-	return 0;
-}
-
 void char_sql_config_read(const char* cfgName)
 {
 	char line[1024], w1[1024], w2[1024];
@@ -5826,7 +5766,7 @@ int do_final(void) {
 			aFree(chr->server[i].map);
 
 	aFree(chr->CHAR_CONF_NAME);
-	aFree(chr->LAN_CONF_NAME);
+	aFree(chr->NET_CONF_NAME);
 	aFree(chr->SQL_CONF_NAME);
 	aFree(chr->INTER_CONF_NAME);
 
@@ -5911,15 +5851,15 @@ static CMDLINEARG(interconfig)
 	return true;
 }
 /**
- * --lan-config handler
+ * --net-config handler
  *
- * Overrides the default subnet configuration file.
+ * Overrides the default network configuration file.
  * @see cmdline->exec
  */
-static CMDLINEARG(lanconfig)
+static CMDLINEARG(netconfig)
 {
-	aFree(chr->LAN_CONF_NAME);
-	chr->LAN_CONF_NAME = aStrdup(params);
+	aFree(chr->NET_CONF_NAME);
+	chr->NET_CONF_NAME = aStrdup(params);
 	return true;
 }
 /**
@@ -5929,7 +5869,7 @@ void cmdline_args_init_local(void)
 {
 	CMDLINEARG_DEF2(char-config, charconfig, "Alternative char-server configuration.", CMDLINE_OPT_PARAM);
 	CMDLINEARG_DEF2(inter-config, interconfig, "Alternative inter-server configuration.", CMDLINE_OPT_PARAM);
-	CMDLINEARG_DEF2(lan-config, lanconfig, "Alternative subnet configuration.", CMDLINE_OPT_PARAM);
+	CMDLINEARG_DEF2(net-config, netconfig, "Alternative network configuration.", CMDLINE_OPT_PARAM);
 }
 
 int do_init(int argc, char **argv) {
@@ -5939,7 +5879,7 @@ int do_init(int argc, char **argv) {
 	char_load_defaults();
 
 	chr->CHAR_CONF_NAME = aStrdup("conf/char-server.conf");
-	chr->LAN_CONF_NAME = aStrdup("conf/subnet.conf");
+	chr->NET_CONF_NAME = aStrdup("conf/network.conf");
 	chr->SQL_CONF_NAME = aStrdup("conf/inter-server.conf");
 	chr->INTER_CONF_NAME = aStrdup("conf/inter-server.conf");
 
@@ -5958,7 +5898,7 @@ int do_init(int argc, char **argv) {
 
 	cmdline->exec(argc, argv, CMDLINE_OPT_NORMAL);
 	chr->config_read(chr->CHAR_CONF_NAME);
-	chr->lan_config_read(chr->LAN_CONF_NAME);
+	sockt->net_config_read(chr->NET_CONF_NAME);
 	chr->sql_config_read(chr->SQL_CONF_NAME);
 
 	if (strcmp(chr->userid, "s1")==0 && strcmp(chr->passwd, "p1")==0) {
@@ -6194,7 +6134,7 @@ void char_defaults(void)
 	chr->parse_frommap = char_parse_frommap;
 	chr->search_mapserver = char_search_mapserver;
 	chr->mapif_init = char_mapif_init;
-	chr->lan_subnetcheck = char_lan_subnetcheck;
+	chr->lan_subnet_check = char_lan_subnet_check;
 	chr->delete2_ack = char_delete2_ack;
 	chr->delete2_accept_actual_ack = char_delete2_accept_actual_ack;
 	chr->delete2_accept_ack = char_delete2_accept_ack;
@@ -6243,7 +6183,6 @@ void char_defaults(void)
 	chr->check_connect_login_server = char_check_connect_login_server;
 	chr->online_data_cleanup_sub = char_online_data_cleanup_sub;
 	chr->online_data_cleanup = char_online_data_cleanup;
-	chr->lan_config_read = char_lan_config_read;
 	chr->sql_config_read = char_sql_config_read;
 	chr->config_dispatch = char_config_dispatch;
 	chr->config_read = char_config_read;
diff --git a/src/char/char.h b/src/char/char.h
index b3aa7bc34..3b6e0fa8c 100644
--- a/src/char/char.h
+++ b/src/char/char.h
@@ -145,7 +145,7 @@ struct char_interface {
 	int new_display;
 
 	char *CHAR_CONF_NAME;
-	char *LAN_CONF_NAME;
+	char *NET_CONF_NAME; ///< Network config filename
 	char *SQL_CONF_NAME;
 	char *INTER_CONF_NAME;
 
@@ -256,7 +256,7 @@ struct char_interface {
 	int (*parse_frommap) (int fd);
 	int (*search_mapserver) (unsigned short map, uint32 ip, uint16 port);
 	int (*mapif_init) (int fd);
-	int (*lan_subnetcheck) (uint32 ip);
+	uint32 (*lan_subnet_check) (uint32 ip);
 	void (*delete2_ack) (int fd, int char_id, uint32 result, time_t delete_date);
 	void (*delete2_accept_actual_ack) (int fd, int char_id, uint32 result);
 	void (*delete2_accept_ack) (int fd, int char_id, uint32 result);
@@ -305,7 +305,6 @@ struct char_interface {
 	int (*check_connect_login_server) (int tid, int64 tick, int id, intptr_t data);
 	int (*online_data_cleanup_sub) (DBKey key, DBData *data, va_list ap);
 	int (*online_data_cleanup) (int tid, int64 tick, int id, intptr_t data);
-	int (*lan_config_read) (const char *lancfgName);
 	void (*sql_config_read) (const char* cfgName);
 	void (*config_dispatch) (char *w1, char *w2);
 	int (*config_read) (const char* cfgName);
diff --git a/src/common/socket.c b/src/common/socket.c
index 17c31db50..830877044 100644
--- a/src/common/socket.c
+++ b/src/common/socket.c
@@ -14,6 +14,7 @@
 #include "common/db.h"
 #include "common/malloc.h"
 #include "common/mmo.h"
+#include "common/nullpo.h"
 #include "common/showmsg.h"
 #include "common/strlib.h"
 #include "common/timer.h"
@@ -1228,6 +1229,21 @@ void socket_final(void)
 	aFree(session[0]);
 
 	aFree(session);
+
+	if (sockt->lan_subnet)
+		aFree(sockt->lan_subnet);
+	sockt->lan_subnet = NULL;
+	sockt->lan_subnet_count = 0;
+
+	if (sockt->allowed_ip)
+		aFree(sockt->allowed_ip);
+	sockt->allowed_ip = NULL;
+	sockt->allowed_ip_count = 0;
+
+	if (sockt->trusted_ip)
+		aFree(sockt->trusted_ip);
+	sockt->trusted_ip = NULL;
+	sockt->trusted_ip_count = 0;
 }
 
 /// Closes a socket.
@@ -1589,6 +1605,164 @@ void send_shortlist_do_sends()
 }
 #endif
 
+/**
+ * Checks whether the given IP comes from LAN or WAN.
+ *
+ * @param[in]  ip   IP address to check.
+ * @param[out] info Verbose output, if requested. Filled with the matching entry. Ignored if NULL.
+ * @retval 0 if it is a WAN IP.
+ * @return the appropriate LAN server address to send, if it is a LAN IP.
+ */
+uint32 socket_lan_subnet_check(uint32 ip, struct s_subnet *info)
+{
+	int i;
+	ARR_FIND(0, sockt->lan_subnet_count, i, (sockt->lan_subnet[i].ip & sockt->lan_subnet[i].mask) == (ip & sockt->lan_subnet[i].mask));
+	if (i < sockt->lan_subnet_count) {
+		if (info) {
+			info->ip = sockt->lan_subnet[i].ip;
+			info->mask = sockt->lan_subnet[i].mask;
+		}
+		return sockt->lan_subnet[i].ip;
+	}
+	if (info) {
+		info->ip = info->mask = 0;
+	}
+	return 0;
+}
+
+/**
+ * Checks whether the given IP is allowed to connect as a server.
+ *
+ * @param ip IP address to check.
+ * @retval true if we allow server connections from the given IP.
+ * @retval false otherwise.
+ */
+bool socket_allowed_ip_check(uint32 ip)
+{
+	int i;
+	ARR_FIND(0, sockt->allowed_ip_count, i, (sockt->allowed_ip[i].ip & sockt->allowed_ip[i].mask) == (ip & sockt->allowed_ip[i].mask) );
+	if (i < sockt->allowed_ip_count)
+		return true;
+	return sockt->trusted_ip_check(ip); // If an address is trusted, it's automatically also allowed.
+}
+
+/**
+ * Checks whether the given IP is trusted and can skip ipban checks.
+ *
+ * @param ip IP address to check.
+ * @retval true if we trust the given IP.
+ * @retval false otherwise.
+ */
+bool socket_trusted_ip_check(uint32 ip)
+{
+	int i;
+	ARR_FIND(0, sockt->trusted_ip_count, i, (sockt->trusted_ip[i].ip & sockt->trusted_ip[i].mask) == (ip & sockt->trusted_ip[i].mask));
+	if (i < sockt->trusted_ip_count)
+		return true;
+	return false;
+}
+
+/**
+ * Helper function to read a list of network.conf values.
+ *
+ * Entries will be appended to the variable-size array pointed to by list/count.
+ *
+ * @param[in]     t         The list to parse.
+ * @param[in,out] list      Pointer to the head of the output array to append to. Must not be NULL (but the array may be empty).
+ * @param[in,out] count     Pointer to the counter of the output array to append to. Must not be NULL (but it may contain zero).
+ * @param[in]     filename  Current filename, for output/logging reasons.
+ * @param[in]     groupname Current group name, for output/logging reasons.
+ * @return The amount of entries read, zero in case of errors.
+ */
+int socket_net_config_read_sub(config_setting_t *t, struct s_subnet **list, int *count, const char *filename, const char *groupname)
+{
+	int i, len;
+	char ipbuf[64], maskbuf[64];
+
+	nullpo_retr(0, list);
+	nullpo_retr(0, count);
+
+	if (t == NULL)
+		return 0;
+
+	len = libconfig->setting_length(t);
+
+	for (i = 0; i < len; ++i) {
+		const char *subnet = libconfig->setting_get_string_elem(t, i);
+		struct s_subnet *l = NULL;
+
+		if (sscanf(subnet, "%63[^:]:%63[^:]", ipbuf, maskbuf) != 2) {
+			ShowWarning("Invalid IP:Subnet entry in configuration file %s: '%s' (%s)\n", filename, subnet, groupname);
+		}
+		RECREATE(*list, struct s_subnet, *count + 1);
+		l = *list;
+		l[*count].ip = str2ip(ipbuf);
+		l[*count].mask = str2ip(maskbuf);
+		++*count;
+	}
+	return *count;
+}
+
+/**
+ * Reads the network configuration file.
+ *
+ * @param filename The filename to read from.
+ */
+void socket_net_config_read(const char *filename)
+{
+	config_t network_config;
+	int i;
+	nullpo_retv(filename);
+
+	if (libconfig->read_file(&network_config, filename)) {
+		ShowError("LAN Support configuration file is not found: '%s'. This server won't be able to accept connections from any servers.\n", filename);
+		return;
+	}
+
+	if (sockt->lan_subnet) {
+		aFree(sockt->lan_subnet);
+		sockt->lan_subnet = NULL;
+	}
+	sockt->lan_subnet_count = 0;
+	if (sockt->net_config_read_sub(libconfig->lookup(&network_config, "lan_subnets"), &sockt->lan_subnet, &sockt->lan_subnet_count, filename, "lan_subnets") > 0)
+		ShowStatus("Read information about %d LAN subnets.\n", sockt->lan_subnet_count);
+
+	if (sockt->trusted_ip) {
+		aFree(sockt->trusted_ip);
+		sockt->trusted_ip = NULL;
+	}
+	sockt->trusted_ip_count = 0;
+	if (sockt->net_config_read_sub(libconfig->lookup(&network_config, "trusted"), &sockt->trusted_ip, &sockt->trusted_ip_count, filename, "trusted") > 0)
+		ShowStatus("Read information about %d trusted IP ranges.\n", sockt->trusted_ip_count);
+	for (i = 0; i < sockt->allowed_ip_count; ++i) {
+		if ((sockt->allowed_ip[i].ip & sockt->allowed_ip[i].mask) == 0) {
+			ShowError("Using a wildcard IP range in the trusted server IPs is NOT RECOMMENDED.\n");
+			ShowNotice("Please edit your '%s' trusted list to fit your network configuration.\n", filename);
+			break;
+		}
+	}
+
+	if (sockt->allowed_ip) {
+		aFree(sockt->allowed_ip);
+		sockt->allowed_ip = NULL;
+	}
+	sockt->allowed_ip_count = 0;
+	if (sockt->net_config_read_sub(libconfig->lookup(&network_config, "allowed"), &sockt->allowed_ip, &sockt->allowed_ip_count, filename, "allowed") > 0)
+		ShowStatus("Read information about %d allowed server IP ranges.\n", sockt->allowed_ip_count);
+	if (sockt->allowed_ip_count == 0) {
+		ShowError("No allowed server IP ranges configured. This server won't be able to accept connections from any char servers.\n");
+	}
+	for (i = 0; i < sockt->allowed_ip_count; ++i) {
+		if ((sockt->allowed_ip[i].ip & sockt->allowed_ip[i].mask) == 0) {
+			ShowWarning("Using a wildcard IP range in the allowed server IPs is NOT RECOMMENDED.\n");
+			ShowNotice("Please edit your '%s' allowed list to fit your network configuration.\n", filename);
+			break;
+		}
+	}
+	libconfig->destroy(&network_config);
+	return;
+}
+
 void socket_defaults(void) {
 	sockt = &sockt_s;
 
@@ -1600,6 +1774,13 @@ void socket_defaults(void) {
 	memset(&sockt->addr_, 0, sizeof(sockt->addr_));
 	sockt->naddr_ = 0;
 	/* */
+	sockt->lan_subnet_count = 0;
+	sockt->lan_subnet = NULL;
+	sockt->allowed_ip_count = 0;
+	sockt->allowed_ip = NULL;
+	sockt->trusted_ip_count = 0;
+	sockt->trusted_ip = NULL;
+
 	sockt->init = socket_init;
 	sockt->final = socket_final;
 	/* */
@@ -1628,4 +1809,10 @@ void socket_defaults(void) {
 	sockt->ntows = ntows;
 	sockt->getips = socket_getips;
 	sockt->set_eof = set_eof;
+
+	sockt->lan_subnet_check = socket_lan_subnet_check;
+	sockt->allowed_ip_check = socket_allowed_ip_check;
+	sockt->trusted_ip_check = socket_trusted_ip_check;
+	sockt->net_config_read_sub = socket_net_config_read_sub;
+	sockt->net_config_read = socket_net_config_read;
 }
diff --git a/src/common/socket.h b/src/common/socket.h
index bd5d9baa2..26b674d43 100644
--- a/src/common/socket.h
+++ b/src/common/socket.h
@@ -6,6 +6,7 @@
 #define COMMON_SOCKET_H
 
 #include "common/cbasetypes.h"
+#include "common/conf.h"
 
 #ifdef WIN32
 #	include "common/winapi.h"
@@ -105,6 +106,12 @@ struct hSockOpt {
 	unsigned int setTimeo : 1;
 };
 
+/// Subnet/IP range in the IP/Mask format.
+struct s_subnet {
+	uint32 ip;
+	uint32 mask;
+};
+
 /// Use a shortlist of sockets instead of iterating all sessions for sockets
 /// that have data to send or need eof handling.
 /// Adapted to use a static array instead of a linked list.
@@ -132,6 +139,14 @@ struct socket_interface {
 	/* */
 	uint32 addr_[16];   // ip addresses of local host (host byte order)
 	int naddr_;   // # of ip addresses
+
+	struct s_subnet *lan_subnet; ///< LAN subnets array
+	int lan_subnet_count;        ///< LAN subnets count
+	struct s_subnet *trusted_ip; ///< Trusted IP ranges array
+	int trusted_ip_count;        ///< Trusted IP ranges count
+	struct s_subnet *allowed_ip; ///< Allowed server IP ranges array
+	int allowed_ip_count;        ///< Allowed server IP ranges count
+
 	/* */
 	void (*init) (void);
 	void (*final) (void);
@@ -165,6 +180,12 @@ struct socket_interface {
 	int (*getips) (uint32* ips, int max);
 	/* */
 	void (*set_eof) (int fd);
+
+	uint32 (*lan_subnet_check) (uint32 ip, struct s_subnet *info);
+	bool (*allowed_ip_check) (uint32 ip);
+	bool (*trusted_ip_check) (uint32 ip);
+	int (*net_config_read_sub) (config_setting_t *t, struct s_subnet **list, int *count, const char *filename, const char *groupname);
+	void (*net_config_read) (const char *filename);
 };
 
 struct socket_interface *sockt;
diff --git a/src/login/login.c b/src/login/login.c
index caace34da..141ab5e2b 100644
--- a/src/login/login.c
+++ b/src/login/login.c
@@ -12,6 +12,7 @@
 #include "login/loginlog.h"
 #include "common/HPM.h"
 #include "common/cbasetypes.h"
+#include "common/conf.h"
 #include "common/core.h"
 #include "common/db.h"
 #include "common/malloc.h"
@@ -238,65 +239,17 @@ bool login_check_password(const char* md5key, int passwdenc, const char* passwd,
 	}
 }
 
-//--------------------------------------------
-// Test to know if an IP come from LAN or WAN.
-//--------------------------------------------
-int login_lan_subnetcheck(uint32 ip)
-{
-	int i;
-	ARR_FIND( 0, login_config.subnet_count, i, (login_config.subnet[i].char_ip & login_config.subnet[i].mask) == (ip & login_config.subnet[i].mask) );
-	return ( i < login_config.subnet_count ) ? login_config.subnet[i].char_ip : 0;
-}
 
-//----------------------------------
-// Reading LAN Support configuration
-//----------------------------------
-int login_lan_config_read(const char *lancfgName)
+/**
+ * Checks whether the given IP comes from LAN or WAN.
+ *
+ * @param ip IP address to check.
+ * @retval 0 if it is a WAN IP.
+ * @return the appropriate LAN server address to send, if it is a LAN IP.
+ */
+uint32 login_lan_subnet_check(uint32 ip)
 {
-	FILE *fp;
-	int line_num = 0;
-	char line[1024], w1[64], w2[64], w3[64], w4[64];
-
-	nullpo_ret(lancfgName);
-	if((fp = fopen(lancfgName, "r")) == NULL) {
-		ShowWarning("LAN Support configuration file is not found: %s\n", lancfgName);
-		return 1;
-	}
-
-	while(fgets(line, sizeof(line), fp))
-	{
-		line_num++;
-		if ((line[0] == '/' && line[1] == '/') || line[0] == '\n' || line[1] == '\n')
-			continue;
-
-		if (sscanf(line, "%63[^:]: %63[^:]:%63[^:]:%63[^\r\n]", w1, w2, w3, w4) != 4) {
-			ShowWarning("Error syntax of configuration file %s in line %d.\n", lancfgName, line_num);
-			continue;
-		}
-
-		if( strcmpi(w1, "subnet") == 0 )
-		{
-			login_config.subnet[login_config.subnet_count].mask = str2ip(w2);
-			login_config.subnet[login_config.subnet_count].char_ip = str2ip(w3);
-			login_config.subnet[login_config.subnet_count].map_ip = str2ip(w4);
-
-			if( (login_config.subnet[login_config.subnet_count].char_ip
-			     & login_config.subnet[login_config.subnet_count].mask) != (login_config.subnet[login_config.subnet_count].map_ip
-			     & login_config.subnet[login_config.subnet_count].mask) )
-			{
-				ShowError("%s: Configuration Error: The char server (%s) and map server (%s) belong to different subnetworks!\n", lancfgName, w3, w4);
-				continue;
-			}
-
-			login_config.subnet_count++;
-		}
-	}
-
-	if( login_config.subnet_count > 1 ) /* only useful if there is more than 1 available */
-		ShowStatus("Read information about %d subnetworks.\n", login_config.subnet_count);
-
-	fclose(fp);
-	return 0;
+	return sockt->lan_subnet_check(ip, NULL);
 }
 
 void login_fromchar_auth_ack(int fd, int account_id, uint32 login_id1, uint32 login_id2, uint8 sex, int request_id, struct login_auth_node* node)
@@ -1233,7 +1186,6 @@ void login_auth_ok(struct login_session_data* sd)
 	int fd = 0;
 	uint32 ip;
 	uint8 server_num, n;
-	uint32 subnet_char_ip;
 	struct login_auth_node* node;
 	int i;
 
@@ -1308,12 +1260,13 @@ void login_auth_ok(struct login_session_data* sd)
 	memset(WFIFOP(fd,20), 0, 24);
 	WFIFOW(fd,44) = 0; // unknown
 	WFIFOB(fd,46) = sex_str2num(sd->sex);
-	for( i = 0, n = 0; i < ARRAYLENGTH(server); ++i )
-	{
+	for (i = 0, n = 0; i < ARRAYLENGTH(server); ++i) {
+		uint32 subnet_char_ip;
+
 		if( !session_isValid(server[i].fd) )
 			continue;
 
-		subnet_char_ip = login->lan_subnetcheck(ip); // Advanced subnet check [LuzZza]
+		subnet_char_ip = login->lan_subnet_check(ip);
 		WFIFOL(fd,47+n*32) = htonl((subnet_char_ip) ? subnet_char_ip : server[i].ip);
 		WFIFOW(fd,47+n*32+4) = ntows(htons(server[i].port)); // [!] LE byte order here [!]
 		memcpy(WFIFOP(fd,47+n*32+6), server[i].name, 20);
@@ -1393,7 +1346,7 @@ void login_auth_failed(struct login_session_data* sd, int result)
 		login_log(ip, sd->userid, result, error); // FIXME: result can be 100, conflicting with the value 100 we use for successful login...
 	}
 
-	if( result == 1 && login_config.dynamic_pass_failure_ban )
+	if (result == 1 && login_config.dynamic_pass_failure_ban && !sockt->trusted_ip_check(ip))
 		ipban_log(ip); // log failed password attempt
 
 #if PACKETVER >= 20120000 /* not sure when this started */
@@ -1590,7 +1543,7 @@ void login_parse_request_connection(int fd, struct login_session_data* sd, const
 		sd->account_id >= 0 &&
 		sd->account_id < ARRAYLENGTH(server) &&
 		!session_isValid(server[sd->account_id].fd) &&
-		login->lan_subnetcheck(ipl))
+		sockt->allowed_ip_check(ipl))
 	{
 		ShowStatus("Connection of the char-server '%s' accepted.\n", server_name);
 		safestrncpy(server[sd->account_id].name, server_name, sizeof(server[sd->account_id].name));
@@ -1637,7 +1590,7 @@ int login_parse_login(int fd)
 	if( sd == NULL )
 	{
 		// Perform ip-ban check
-		if( login_config.ipban && ipban_check(ipl) )
+		if (login_config.ipban && !sockt->trusted_ip_check(ipl) && ipban_check(ipl))
 		{
 			ShowStatus("Connection refused: IP isn't authorized (deny/allow, ip: %s).\n", ip);
 			login_log(ipl, "unknown", -3, "ip banned");
@@ -1759,7 +1712,6 @@ void login_set_defaults()
 
 	login_config.client_hash_check = 0;
 	login_config.client_hash_nodes = NULL;
-	login_config.subnet_count = 0;
 }
 
 //-----------------------------------
@@ -1929,7 +1881,7 @@ int do_final(void) {
 	HPM_login_do_final();
 
 	aFree(login->LOGIN_CONF_NAME);
-	aFree(login->LAN_CONF_NAME);
+	aFree(login->NET_CONF_NAME);
 
 	HPM->event(HPET_POST_FINAL);
 
@@ -1984,15 +1936,15 @@ static CMDLINEARG(loginconfig)
 	return true;
 }
 /**
- * --lan-config handler
+ * --net-config handler
  *
  * Overrides the default subnet configuration file.
  * @see cmdline->exec
  */
-static CMDLINEARG(lanconfig)
+static CMDLINEARG(netconfig)
 {
-	aFree(login->LAN_CONF_NAME);
-	login->LAN_CONF_NAME = aStrdup(params);
+	aFree(login->NET_CONF_NAME);
+	login->NET_CONF_NAME = aStrdup(params);
 	return true;
 }
 /**
@@ -2001,7 +1953,7 @@ static CMDLINEARG(lanconfig)
 void cmdline_args_init_local(void)
 {
 	CMDLINEARG_DEF2(login-config, loginconfig, "Alternative login-server configuration.", CMDLINE_OPT_PARAM);
-	CMDLINEARG_DEF2(lan-config, lanconfig, "Alternative subnet configuration.", CMDLINE_OPT_PARAM);
+	CMDLINEARG_DEF2(net-config, netconfig, "Alternative subnet configuration.", CMDLINE_OPT_PARAM);
 }
 
 //------------------------------
@@ -2025,7 +1977,7 @@ int do_init(int argc, char** argv)
 	login_set_defaults();
 
 	login->LOGIN_CONF_NAME = aStrdup("conf/login-server.conf");
-	login->LAN_CONF_NAME   = aStrdup("conf/subnet.conf");
+	login->NET_CONF_NAME   = aStrdup("conf/network.conf");
 
 	HPM_login_do_init();
 	HPM->symbol_defaults_sub = login_hp_symbols;
@@ -2035,7 +1987,7 @@ int do_init(int argc, char** argv)
 
 	cmdline->exec(argc, argv, CMDLINE_OPT_NORMAL);
 	login_config_read(login->LOGIN_CONF_NAME);
-	login->lan_config_read(login->LAN_CONF_NAME);
+	sockt->net_config_read(login->NET_CONF_NAME);
 
 	for( i = 0; i < ARRAYLENGTH(server); ++i )
 		chrif_server_init(i);
@@ -2112,8 +2064,7 @@ void login_defaults(void) {
 	login->sync_ip_addresses = login_sync_ip_addresses;
 	login->check_encrypted = login_check_encrypted;
 	login->check_password = login_check_password;
-	login->lan_subnetcheck = login_lan_subnetcheck;
-	login->lan_config_read = login_lan_config_read;
+	login->lan_subnet_check = login_lan_subnet_check;
 
 	login->fromchar_auth_ack = login_fromchar_auth_ack;
 	login->fromchar_accinfo = login_fromchar_accinfo;
@@ -2159,5 +2110,5 @@ void login_defaults(void) {
 	login->send_coding_key = login_send_coding_key;
 
 	login->LOGIN_CONF_NAME = NULL;
-	login->LAN_CONF_NAME = NULL;
+	login->NET_CONF_NAME = NULL;
 }
diff --git a/src/login/login.h b/src/login/login.h
index de504db07..6dc4c875b 100644
--- a/src/login/login.h
+++ b/src/login/login.h
@@ -101,14 +101,6 @@ struct Login_Config {
 
 	int client_hash_check;                          ///< flags for checking client md5
 	struct client_hash_node *client_hash_nodes;     ///< linked list containg md5 hash for each gm group
-
-	/// Advanced subnet check [LuzZza]
-	struct s_subnet {
-		uint32 mask;
-		uint32 char_ip;
-		uint32 map_ip;
-	} subnet[16];
-	int subnet_count;
 };
 
 struct login_auth_node {
@@ -163,8 +155,7 @@ struct login_interface {
 	int (*sync_ip_addresses) (int tid, int64 tick, int id, intptr_t data);
 	bool (*check_encrypted) (const char* str1, const char* str2, const char* passwd);
 	bool (*check_password) (const char* md5key, int passwdenc, const char* passwd, const char* refpass);
-	int (*lan_subnetcheck) (uint32 ip);
-	int (*lan_config_read) (const char *lancfgName);
+	uint32 (*lan_subnet_check) (uint32 ip);
 	void (*fromchar_accinfo) (int fd, int account_id, int u_fd, int u_aid, int u_group, int map_fd, struct mmo_account *acc);
 	void (*fromchar_account) (int fd, int account_id, struct mmo_account *acc);
 	void (*fromchar_account_update_other) (int account_id, unsigned int state);
@@ -207,7 +198,7 @@ struct login_interface {
 	void (*parse_request_connection) (int fd, struct login_session_data* sd, const char *ip, uint32 ipl);
 	int (*parse_login) (int fd);
 	char *LOGIN_CONF_NAME;
-	char *LAN_CONF_NAME;
+	char *NET_CONF_NAME; ///< Network configuration filename
 };
 
 struct login_interface *login;