SIGUSR1 support and some code improvement

README.md

@@ -1,9 +1,11 @@
 # tuninetd
 
-Simple yet powerful event emitter by **tun/tap** (with/without **pcap** filter) or **nflog** source. Could be used as: VPN dispatcher, simplified detection system, by demand services handler, etc...
+Simple yet powerful event emitter by **tun/tap** (with/without **pcap** filter) or **nflog** source. 
 
-### 1. How it works.
-#### tun/tap device: ####
+Could be used as: VPN dispatcher, simplified detection system, by demand service handler, tricky lock etc...
+
+### 1. How it works:
+#### 1.1. tun/tap + pcap mode:
 You should create and configure tun/tap device first, then run **tuninetd**. It starts listening on this interface, until network traffic will be detected. After that, interface immediately releasing and specified command (with -c) will execute. From now on, daemon in monitoring state.
 
 ---
@@ -24,7 +26,7 @@ Since **tuninetd** based on **libpcap**, you can specify capture filter. To test
 
 >**! Notice !** *Modern Linux distributions periodically send 'icmpv6 router solicitation' packets, which cause tuninetd keep or change state. This situation appears in tun/tap mode without pcap filter applied.*
 
-#### NFLOG: ####
+#### 1.2. nflog mode:
 
 In general, behavior the same as tun/tap in part of start/stop. You could simply use netfilter nfgroup (*iptables **NFLOG** target*) to reading packets from. No binding to tun/tap device nor libpcap sensor. This is more lightweight mode and, because of that, - more reliable.
 
@@ -43,19 +45,28 @@ To install from sources download src folder. In case Debian/Ubuntu, you should a
 Congrats! Tuninend ready to use. Check ./bin folder.
 
 ### 3. Usage:
+#### 3.1. Launch:
 
-tuninetd {-i \<ifname> | -n \<nflog-group>} -c \<path> [-m \<iftype>] [-f \<filter>] [-t \<ttl>] [-d]
+```sh
+# tuninetd {-i <ifname> | -n <nflog-group>} -c <path> [-m <iftype>] [-f <filter>] [-t <ttl>] [-d]
+```
 
 **-i \<ifname>**: interface to use (tun or tap). Must be up and configured.<br/>
-**-n \<nflog-group>**: iptables NFLOG group number ('-i', '-m' and '-f' will be ignored).<br/>
-**-c \<path>**: will be executed with 'start' and 'stop' parameter.<br/>
+**-n \<nflog-group>**: iptables NFLOG group ('-i', '-m' and '-f' will be ignored).<br/>
+**-c \<path>**: will execute with 'start' and 'stop' parameter.<br/>
 **-m \<iftype>**: 'tun' or 'tap' mode. By default 'tun', should be set properly.<br/>
 **-f \<filter>**: specify pcap filter, similar to tcpdump<br/>
-**-t \<ttl>**: seconds of interface (traffic) idle, before 'stop' command (default is 600).<br/>
-**-d**: demonize process<br/>
+**-t \<ttl>**: seconds since last packet before 'stop' command (default is 600).<br/>
+**-d**: daemonize process<br/>
 **-h**: print this help
 
-`--- If tuninetd stuck in start condition for any reason, you can reset to "standby" (i.e. stop state) with SIGHUP. ---`
+---
+
+#### 3.2. Signals:
+SIGHUP  (-1): switch tuninetd to standby mode (deadlock resolving)<br/>
+SIGUSR1 (-10): write to syslog current state (debug information)
+
+
 
 ### 4. Examples:
 Before launching as a daemon make sure there is no errors. In daemon mode tuninetd write status messages and errors to syslog.
@@ -67,13 +78,29 @@ Before launching as a daemon make sure there is no errors. In daemon mode tunine
 
 Check ```example``` folder to find some shell scripts.
 
-To create and bring up ```tun``` device, could be used following commands:
+To create and bring up ```tun``` device could be used following commands:
 ```sh
 # ip tuntap add dev tun0 mode tun
 # ip link set tun0 up
 ```
 
-For more information about routing and configuring network devices, I strongly suggest LARCT how-to.
+For more information about routing and configuring network devices, I strongly suggest LARTC how-to.
+
+<br/>
+
+---
+```sh
+# killall -10 tuninetd 
+```
+syslog:<br/>
+
+>Oct 20 18:42:20 router1 tuninetd: SIGUSR1 caught:<br/>
+>Oct 20 18:42:20 router1 tuninetd: - Capture engine: nflog group 1<br/>
+>Oct 20 18:42:20 router1 tuninetd: - cmd_path = /etc/tuninetd/toggletunnel.sh<br/>
+>Oct 20 18:42:20 router1 tuninetd: - TTL = 600 sec.<br/>
+>Oct 20 18:42:20 router1 tuninetd: - Current status: up (ON), time since last captured packet: 2 sec.
+---
+
 
 ### License:
 MIT

src/Makefile

@@ -1,26 +1,29 @@
+CFLAGS = -Wall -O2
+
 all: tuninetd
-tuninetd: main.o nflog.o pcap.o thread.o tun.o utils.o
+
+tuninetd: main.o xnflog.o xpcap.o thread.o xtun.o utils.o
 	[ -d ./bin ] || mkdir -p ./bin
-	gcc main.o nflog.o pcap.o thread.o tun.o utils.o -o ./bin/tuninetd -lpthread -lpcap -lnetfilter_log
+	gcc main.o xnflog.o xpcap.o thread.o xtun.o utils.o -o ./bin/tuninetd -lpthread -lpcap -lnetfilter_log
 
-main.o: main.c main.h
-	gcc -c main.c
+main.o: main.c main.h common.h
+	gcc $(CFLAGS) -c main.c
 
-nflog.o: nflog.c main.h
-	gcc -c nflog.c
+xnflog.o: xnflog.c common.h
+	gcc $(CFLAGS) -c xnflog.c
 
-pcap.o: pcap.c main.h
-	gcc -c pcap.c
+xpcap.o: xpcap.c common.h
+	gcc $(CFLAGS) -c xpcap.c
 
-thread.o: thread.c main.h
-	gcc -c thread.c
+thread.o: thread.c common.h
+	gcc $(CFLAGS) -c thread.c
 
-tun.o: tun.c main.h
-	gcc -c tun.c
+xtun.o: xtun.c common.h
+	gcc $(CFLAGS) -c xtun.c
 
-utils.o: utils.c main.h
-	gcc -c utils.c
+utils.o: utils.c common.h
+	gcc $(CFLAGS) -c utils.c
 
 clean:
-	rm -f *.o tuninetd
-	rm -rf ./bin
+	rm -f *.o
+	rm -rf ./bin

src/common.h

@@ -0,0 +1,61 @@
+#ifndef H_TUNINETD_COMMON
+#define H_TUNINETD_COMMON
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <linux/if_tun.h>
+#include <unistd.h>
+#include <time.h>
+
+#define BUFSIZE 2000
+#define ON 1
+#define OFF 0
+
+#define ERROR 0
+#define WARNING 1
+#define INFO 2
+
+#define VERSION "\ntuninetd 1.3.0\n"
+
+//global vars.
+short int debug;
+short int status;
+unsigned long ts;
+unsigned long curts;
+
+struct globcfg_t {
+    short int isdaemon;
+    pid_t pid;
+    char *cmd_path;
+    char *cmd_path_start;
+    char *cmd_path_stop;
+    char *pcap_filter;
+    char *dev_name;
+    long nf_group;
+    int dev_mode;
+    long ttl;
+} globcfg;
+
+
+//from utils.c
+void do_debug(const char *msg, ...);
+void message(int, const char *msg, ...);
+
+void sighup_handler(int signo);
+void sigusr_handler(int signo);
+void usage();
+void version();
+
+//from thread.c
+void switch_guard(short action);
+void thread_init();
+
+void *tun_x(void *x_void_ptr);
+void *nflog_x(void *x_void_ptr);
+void *pcap_x(void *x_void_ptr);
+
+#endif

src/main.c

@@ -2,28 +2,60 @@
 
 int main(int argc, char *argv[])
 {
-    int opt = 0;
-
-    struct timespec tim;
+    curts = time(NULL);
 
-    //debug = 1;
+    build_config(argc, argv);
+    check_config_and_daemonize();
+    thread_init(); //Initialize our workers (thread.c)
+
+    struct timespec tim;
 
     tim.tv_sec = 1;
     tim.tv_nsec = 0;
-
+
+    //debug = 1;
+
+    if (signal(SIGHUP, sighup_handler) == SIG_ERR) {
+         message(WARNING, "Warning! Can't catch SIGHUP");
+    }
+
+    if (signal(SIGUSR1, sigusr_handler) == SIG_ERR) {
+         message(WARNING, "Warning! Can't catch SIGUSR1");
+    }
+
+    while (1) {
+
+        nanosleep(&tim, NULL); //Tick
+
+        curts = time(NULL);
+
+        if (ts != 0 && status == ON && ((long)(curts - ts) >= globcfg.ttl)) {
+            message(INFO, "CORE: executing STOP command...");
+            switch_guard(OFF);
+        }
+    }
+
+    free(globcfg.cmd_path_start);
+    free(globcfg.cmd_path_stop);
+
+    return 0;
+}
+
+
+void build_config(int argc, char **argv)
+{
+    int opt = 0;
     static const char *optString = "i:t:c:f:m:n:dhv";
-
-    curts = time(NULL);
-
+
     globcfg.isdaemon = 0;
     globcfg.pid = 0;
     globcfg.cmd_path = NULL;
     globcfg.ttl = 600;
     globcfg.dev_mode = IFF_TUN;
     globcfg.nf_group = -1;
-    
+
     opt = getopt( argc, argv, optString);
-    
+
     while( opt != -1 ) {
         switch( opt ) {
             case 'v':
@@ -41,12 +73,12 @@ int main(int argc, char *argv[])
                 globcfg.cmd_path_start = malloc(strlen(optarg) + 23);
                 strcpy(globcfg.cmd_path_start, optarg);
                 strcat(globcfg.cmd_path_start, " start > /dev/null 2>&1");
-                
+
                 globcfg.cmd_path_stop = malloc(strlen(optarg) + 22);
                 strcpy(globcfg.cmd_path_stop, optarg);
                 strcat(globcfg.cmd_path_stop, " stop > /dev/null 2>&1");
                 break;
-                
+
             case 'f':
                 globcfg.pcap_filter = optarg;
                 break;
@@ -69,68 +101,47 @@ int main(int argc, char *argv[])
                 exit(1);
                 break;
         }
-         
-        opt = getopt( argc, argv, optString );
+
+        opt = getopt(argc, argv, optString);
     }
-
+}
+
+void check_config_and_daemonize()
+{
     if (globcfg.dev_name == NULL && globcfg.nf_group < 0) {
-        my_err("tun/tap device OR nfgroup must be specified.");
+        message(ERROR, "tun/tap device OR nfgroup must be specified. Abort.");
         usage();
         exit(1);
     }
-    
+
     if (globcfg.cmd_path == NULL) {
-        my_err("Executable path must be specified");
+        message(ERROR, "Executable path must be specified. Abort.");
         usage();
         exit(1);
     }
-
-
+
     if (globcfg.isdaemon == 1) {
         globcfg.pid = fork();
-        
+
         if (globcfg.pid < 0) {
-            my_err("Can't fork process. Abort.");
+            message(ERROR, "Can't fork process. Abort.");
             exit(1);
         }
 
         if (globcfg.pid > 0) {
-            my_info("---");
-            my_info("Success! tuninetd has been started with pid: %i", globcfg.pid);
+            message(INFO, "---");
+            message(INFO, "Success! Tuninetd has been started with PID: %i", globcfg.pid);
             exit(0);
         }
 
         chdir("/");
-        
+
         setsid();
-       
+
         close(STDIN_FILENO);
         close(STDOUT_FILENO);
         close(STDERR_FILENO);
-    } else 
-        my_info("Started with pid %d", getpid());    
-
-    thread_init(); //Initialization our workers (thread.c)
-
-    if (signal(SIGHUP, sig_handler) == SIG_ERR)
-         my_info("Can't catch SIGHUP\n");
-
-
-    while (1) {
-
-        nanosleep(&tim, NULL); //Tick
-
-        curts = time(NULL);
-        //do_debug("Tick %lu ...\n", curts);//
-
-        if (ts != 0 && status == 1 && ((curts - ts) >= globcfg.ttl) ) {
-            my_info("CORE: executing STOP command...");
-            switch_guard(OFF);
-        }
+    } else {
+        message(INFO, "Started with pid %d", getpid());
     }
-
-    free(globcfg.cmd_path_start);
-    free(globcfg.cmd_path_stop);
-
-    return 0;
 }