Merge pull request #66 from kennylam777/master

Added support for dynamic ip

README.md

@@ -91,8 +91,8 @@ git version:6e1df4b39f    build date:Oct 24 2017 09:21:15
 repository: https://github.com/wangyu-/udp2raw-tunnel
 
 usage:
-    run as client : ./this_program -c -l local_listen_ip:local_port -r server_ip:server_port  [options]
-    run as server : ./this_program -s -l server_listen_ip:server_port -r remote_ip:remote_port  [options]
+    run as client : ./this_program -c -l local_listen_ip:local_port -r remote_host:server_port  [options]
+    run as server : ./this_program -s -l server_listen_ip:server_port -r remote_host:remote_port  [options]
 
 common options,these options must be same on both side:
     --raw-mode            <string>        avaliable values:faketcp(default),udp,icmp

common.h

@@ -24,6 +24,7 @@
 #include <sys/stat.h>
 #include <stdlib.h> //for exit(0);
 #include <errno.h> //For errno - the error number
+#include <netdb.h> // for gethostbyname()
 #include <netinet/tcp.h>   //Provides declarations for tcp header
 #include <netinet/udp.h>
 #include <netinet/ip.h>    //Provides declarations for ip header

doc/README.zh-cn.md

@@ -119,8 +119,8 @@ git version:6e1df4b39f    build date:Oct 24 2017 09:21:15
 repository: https://github.com/wangyu-/udp2raw-tunnel
 
 usage:
-    run as client : ./this_program -c -l local_listen_ip:local_port -r server_ip:server_port  [options]
-    run as server : ./this_program -s -l server_listen_ip:server_port -r remote_ip:remote_port  [options]
+    run as client : ./this_program -c -l local_listen_ip:local_port -r remote_host:server_port  [options]
+    run as server : ./this_program -s -l server_listen_ip:server_port -r remote_host:remote_port  [options]
 
 common options,these options must be same on both side:
     --raw-mode            <string>        avaliable values:faketcp(default),udp,icmp

main.cpp

@@ -826,6 +826,7 @@ int server_on_raw_recv_ready(conn_info_t &conn_info,char * ip_port,char type,cha
 						tmp_conv_id);
 				return 0;
 			}
+			
 			struct sockaddr_in remote_addr_in={0};
 
 			socklen_t slen = sizeof(sockaddr_in);
@@ -1072,7 +1073,7 @@ int client_event_loop()
 			{
 				if(find_lower_level_info(remote_ip_uint32,dest_ip,if_name_string,hw_string)!=0)
 				{
-					mylog(log_fatal,"auto detect lower-level info failed for %s,specific it manually\n",remote_ip);
+					mylog(log_fatal,"auto detect lower-level info failed for %s,specific it manually\n",remote_host);
 					myexit(-1);
 				}
 			}
@@ -1083,7 +1084,7 @@ int client_event_loop()
 				{
 					if(find_lower_level_info(remote_ip_uint32,dest_ip,if_name_string,hw_string)!=0)
 					{
-						mylog(log_warn,"auto detect lower-level info failed for %s,retry in %d seconds\n",remote_ip,retry_on_error_interval);
+						mylog(log_warn,"auto detect lower-level info failed for %s,retry in %d seconds\n",remote_host,retry_on_error_interval);
 						sleep(retry_on_error_interval);
 					}
 					else
@@ -1121,7 +1122,7 @@ int client_event_loop()
 		}
 
 	}
-	//printf("?????\n");
+	
 	if(source_ip_uint32==0)
 	{
 		mylog(log_info,"get_src_adress called\n");
@@ -1757,8 +1758,17 @@ int main(int argc, char *argv[])
 		mylog(log_warn,"you can run udp2raw with non-root account for better security. check README.md in repo for more info.\n");
 	}
 
+
+	struct hostent        *he;
+	if ( (he = gethostbyname(remote_host) ) == NULL ) {
+		mylog(log_error,"Unable to resolve hostname: %s\n",remote_host);
+		exit(1); /* error */
+	}
+	struct in_addr **addr_list = (struct in_addr **)he->h_addr_list;
+	remote_ip_uint32=(*addr_list[0]).s_addr;
+	mylog(log_info,"%s ip = %s\n", program_mode==client_mode?"server":"remote", my_ntoa(remote_ip_uint32));
+
 	local_ip_uint32=inet_addr(local_ip);
-	remote_ip_uint32=inet_addr(remote_ip);
 	source_ip_uint32=inet_addr(source_ip);
 
 

misc.cpp

@@ -25,9 +25,9 @@ int max_rst_allowed=-1;
 
 fd_manager_t fd_manager;
 
-char local_ip[100]="0.0.0.0", remote_ip[100]="255.255.255.255",source_ip[100]="0.0.0.0";//local_ip is for -l option,remote_ip for -r option,source for --source-ip
+char local_ip[100]="0.0.0.0", remote_host[100]="255.255.255.255",source_ip[100]="0.0.0.0";//local_ip is for -l option,remote_host for -r option,source for --source-ip
 u32_t local_ip_uint32,remote_ip_uint32,source_ip_uint32;//convert from last line.
-int local_port = -1, remote_port=-1,source_port=0;//similiar to local_ip  remote_ip,buf for port.source_port=0 indicates --source-port is not enabled
+int local_port = -1, remote_port=-1,source_port=0;//similiar to local_ip  remote_host,buf for port.source_port=0 indicates --source-port is not enabled
 
 int force_source_ip=0; //if --source-ip is enabled
 
@@ -118,8 +118,8 @@ void print_help()
 	printf("repository: https://github.com/wangyu-/udp2raw-tunnel\n");
 	printf("\n");
 	printf("usage:\n");
-	printf("    run as client : ./this_program -c -l local_listen_ip:local_port -r server_ip:server_port  [options]\n");
-	printf("    run as server : ./this_program -s -l server_listen_ip:server_port -r remote_ip:remote_port  [options]\n");
+	printf("    run as client : ./this_program -c -l local_listen_ip:local_port -r server_host:server_port  [options]\n");
+	printf("    run as server : ./this_program -s -l server_listen_ip:server_port -r remote_host:remote_port  [options]\n");
 	printf("\n");
 	printf("common options,these options must be same on both side:\n");
 	printf("    --raw-mode            <string>        avaliable values:faketcp(default),udp,icmp\n");
@@ -393,7 +393,7 @@ void process_arg(int argc, char *argv[])  //process all options
 		case 'r':
 			no_r = 0;
 			if (strchr(optarg, ':') != 0) {
-				sscanf(optarg, "%[^:]:%d", remote_ip, &remote_port);
+				sscanf(optarg, "%[^:]:%d", remote_host, &remote_port);
 				if(remote_port==22)
 				{
 					mylog(log_fatal,"port 22 not allowed\n");
@@ -683,7 +683,7 @@ void process_arg(int argc, char *argv[])  //process all options
 
 	 log_bare(log_info,"local_ip=%s ",local_ip);
 	 log_bare(log_info,"local_port=%d ",local_port);
-	 log_bare(log_info,"remote_ip=%s ",remote_ip);
+	 log_bare(log_info,"remote_host=%s ",remote_host);
 	 log_bare(log_info,"remote_port=%d ",remote_port);
 	 log_bare(log_info,"source_ip=%s ",source_ip);
 	 log_bare(log_info,"source_port=%d ",source_port);
@@ -848,15 +848,15 @@ void iptables_rule()  // handles -a -g --gen-add  --keep-rule --clear --wait-loc
 	{
 		if(raw_mode==mode_faketcp)
 		{
-			sprintf(tmp_pattern,"-s %s/32 -p tcp -m tcp --sport %d",remote_ip,remote_port);
+			sprintf(tmp_pattern,"-s %s/32 -p tcp -m tcp --sport %d",my_ntoa(remote_ip_uint32),remote_port);
 		}
 		if(raw_mode==mode_udp)
 		{
-			sprintf(tmp_pattern,"-s %s/32 -p udp -m udp --sport %d",remote_ip,remote_port);
+			sprintf(tmp_pattern,"-s %s/32 -p udp -m udp --sport %d",my_ntoa(remote_ip_uint32),remote_port);
 		}
 		if(raw_mode==mode_icmp)
 		{
-			sprintf(tmp_pattern,"-s %s/32 -p icmp",remote_ip);
+			sprintf(tmp_pattern,"-s %s/32 -p icmp",my_ntoa(remote_ip_uint32));
 		}
 		pattern=tmp_pattern;
 	}

misc.h

@@ -69,9 +69,9 @@ union current_state_t
 	client_current_state_t client_current_state;
 };
 
-extern char local_ip[100], remote_ip[100],source_ip[100];//local_ip is for -l option,remote_ip for -r option,source for --source-ip
+extern char local_ip[100], remote_host[100],source_ip[100];//local_ip is for -l option,remote_host for -r option,source for --source-ip
 extern u32_t local_ip_uint32,remote_ip_uint32,source_ip_uint32;//convert from last line.
-extern int local_port , remote_port,source_port;//similiar to local_ip  remote_ip,buf for port.source_port=0 indicates --source-port is not enabled
+extern int local_port , remote_port,source_port;//similiar to local_ip  remote_host,buf for port.source_port=0 indicates --source-port is not enabled
 
 extern int force_source_ip; //if --source-ip is enabled