SIGHUP support

README.md

@@ -1,34 +1,33 @@
 # tuninetd
 
-Is a simple Linux daemon for tun/tap devices, similar to inetd by its logic, but for mentioned interfaceces, instead of a ports.
+Simple yet powerful tun/tap event emitter. Could be used like VPN dispatcher...
 
 ### How it works:
-First, you create and configure tun/tap device, then run **tuninetd**. It start listening on that interface, until network packet will be received.
-Next, interface will be released and certain command is executed. From now on, daemon in monitoring state.
-After N seconds of interface idle, tuninetd send "stop" command by path, that you define, and start listening interface by its own again.
-
-Since, **tuninetd** based on **libpcap**, you can specify filter to trigging "start" event and monitoring iddle (i.e. cutoff unwanted traffic).
-To test/debug filters rules - use tcpdump, because it built upon the same library.
+You should create and configure tun/tap device, then run **tuninetd**. It starts listening on that interface until network traffic will be detected. After that, interface will be released and certain command executed. From now on daemon is in monitoring state.
+After N seconds of interface idle, tuninetd send "stop" command by path that you define and start listening interface by its own again.
+
+Since **tuninetd** based on **libpcap**, you can specify filter to trigging "start" and monitoring iddle (i.e. cutoff unwanted traffic). To test/debug pcap rules you might use tcpdump which is based on the same library.
 
 **! OR !**
 
-You can simply use netfilter nfgroup (*iptables NFLOG target*), for reading packets from. No binding to interface and no libpcap usage. This is more lightweight mode and because of that - more reliable. Option available since v1.1.0.
+You can simply use netfilter nfgroup (*iptables NFLOG target*), for reading packets from. No need binding to tun/tap interface nor heavy libpcap sensor. This is more lightweight mode and because of that - more reliable. Option available since v1.1.0.
 
 
-**tuninetd** allows you deploy "VPN by demand" or any other "by demand" services, which is the main idea of the project.
+**tuninetd** allows deploy "VPN by demand" or any other "by demand" services, which is the main idea of the project.
 
 ### Installation:
-If you're using Debian/Ubuntu, check deb-packages folder. Choose appropriate architecture, then run following command with root privileges:
+If you're using Debian/Ubuntu please check deb-packages folder. Choose appropriate architecture, then run following command with root privileges:
 ```sh
 # dpkg -i tuninetd_ver_arch.deb
 # apt-get -f install
 ```
-To install it from sources, download src folder. In case Debian/Ubuntu, you should also install **build-essential**, **libpcap-dev** and **libnetfilter-log-dev** packages first. To build tuninetd, run:<br/>
+To install from sources download src folder. In case Debian/Ubuntu, you should also install **build-essential**, **libpcap-dev** and **libnetfilter-log-dev** packages first. To build tuninetd just run:<br/>
 ```sh
 # cd /download/folder/src
 # make
 ```
-After that, bin folder should appears, which contains tuninetd.
+
+Congrats! Tuninend is ready to use. Check ./bin folder. :)
 
 ### Usage:
 
@@ -41,30 +40,32 @@ tuninetd {-i \<ifname> | -n \<nflog-group>} -c \<path> [-m \<iftype>] [-f \<filt
 **-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/>
-**-h**: prints this help text
+**-h**: prints this help
+
+`--- If tuninetd stuck in start condition for any reason, you can reset to "standby" (i.e. stop state) with SIGHUP. ---`
 
 ### Examples:
-Before launching as daemon, make sure there is no errors occurs. In daemon mode, tuninetd write status messages and errors to syslog.
+Before launching as daemon make sure there is no errors occurs. In daemon mode tuninetd write status messages and errors to syslog.
 
 ```sh
 # tuninetd -i tun0 -c /test/runtunnel.sh -f "! host 1.2.3.4" -t 3600 -d
 # tuninetd -n 2 -c /test/runtunnel.sh -t 3600 -d
 ```
 
-You can find example script 'runtunnel.sh', within examples folder.
+Check ```example``` folder to find some shell scripts.
 
-To create and up tun device, could be used next commands:
+To create and bring up ```tun``` device, could be used following commands:
 ```sh
 # ip tuntap add name tun0 mode tun
-# ip link tun0 up
+# ip link set tun0 up
 ```
 
-For more information about routing and configuring net devices, please check official documentation.
+For more information about routing and configuring net devices, I strongly suggest LARCT how-to.
 
-*! Notice, that the modern Linux distributions periodically send 'icmpv6 router solicitation' packets, which cause tuninetd state changing (call of 'start' script). This situation affects to tun/tap mode without filter (-f) applied.*
+*! Notice ! Modern Linux distributions periodically send 'icmpv6 router solicitation' packets, which cause tuninetd keep or change its status (calling 'start' script for example). This situation appears in tun/tap mode without pcap filter applied.*
 
 ### License:
 MIT
 ### Author:
 Paul aka root4root \<root4root at gmail dot com><br/>
-**Any suggestions will be appreciated.**
+**Any comment/suggestions are welcomed.**

src/Makefile

@@ -1,3 +1,6 @@
-first: main.c
+all: default
+default: main.c
 	[ -d ./bin ] || mkdir -p ./bin
 	gcc -o ./bin/tuninetd main.c -lpthread -lpcap -lnetfilter_log
+clean:
+	rm -rf ./bin

src/main.c

@@ -1,50 +1,13 @@
-#include <fcntl.h>
-#include <pthread.h>
-#include <pcap.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <net/if.h>
-#include <linux/if_tun.h>
-#include <sys/ioctl.h>
-#include <stdarg.h>
-#include <syslog.h>
-#include <unistd.h>
-
-//#include <sys/types.h>
-#include <libnetfilter_log/libnetfilter_log.h>
-//#include <sys/socket.h>
-
-#define BUFSIZE 2000
-
-short int debug = 0;
-short int status = 0;
-unsigned long ts = 0;
-unsigned long curts = 0;
-
-char progname[] = "tuninetd";
-
-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;
-    int ttl;
-} globcfg;
-
-#include "utils.c"
-#include "tun.c"
-#include "pcap.c"
-#include "nflog.c"
+#include "main.h"
 
 int main(int argc, char *argv[])
 {
-    int x, y, opt=0;
+    int opt = 0;
+
+    struct timespec tim;
+
+    tim.tv_sec = 1;
+    tim.tv_nsec = 0;
 
     static const char *optString = "i:t:c:f:m:n:dh";
 
@@ -117,6 +80,12 @@ int main(int argc, char *argv[])
         exit(1);
     }
 
+    if (pthread_mutex_init(&lock, NULL) != 0)
+    {
+        my_err("Mutex init failed. Abort.");
+        exit(1);
+    }
+
     if (globcfg.isdaemon == 1) {
         globcfg.pid = fork();
 
@@ -138,14 +107,10 @@ int main(int argc, char *argv[])
         close(STDIN_FILENO);
         close(STDOUT_FILENO);
         close(STDERR_FILENO);
-    }
+    } else 
+        my_info("Started with pid %d", getpid());    
 
-    pthread_t pcap_x_thread;
-    pthread_t tun_x_thread;
-    pthread_t nflog_x_thread;
 
-    pthread_attr_t attr;
-
     pthread_attr_init(&attr);
     pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 
@@ -158,22 +123,19 @@ int main(int argc, char *argv[])
         pthread_create(&nflog_x_thread, &attr, nflog_x, &y);
     }
 
+    if (signal(SIGHUP, sig_handler) == SIG_ERR)
+         my_info("Can't catch SIGHUP\n");
+
+
     while (1) {
-        usleep(1000000);
+
+        nanosleep(&tim, NULL);
+
         curts = time(NULL);
 
         if (ts != 0 && status == 1 && ((curts - ts) >= globcfg.ttl) ) {
             my_info("CORE: executing STOP command...");
-
-            if (system(globcfg.cmd_path_stop) != 0) {
-                my_err("Warning! Executable command doesn't return 0 (%s)", globcfg.cmd_path_stop);
-            }
-
-            status = 0;
-
-            if (globcfg.nf_group < 0) {
-                pthread_create(&tun_x_thread, &attr, tun_x, &y);
-            }
+            switch_guard(OFF);
         }
     }
 

src/main.h

@@ -0,0 +1,65 @@
+#include <fcntl.h>
+#include <pthread.h>
+#include <pcap.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <net/if.h>
+#include <linux/if_tun.h>
+#include <sys/ioctl.h>
+#include <stdarg.h>
+#include <syslog.h>
+#include <unistd.h>
+#include <signal.h>
+#include <time.h>
+
+#include <libnetfilter_log/libnetfilter_log.h>
+
+
+#define BUFSIZE 2000
+#define ON 1
+#define OFF 0
+
+int x, y;
+
+short int debug = 0;
+short int status = 0;
+unsigned long ts = 0;
+unsigned long curts = 0;
+
+char progname[] = "tuninetd";
+
+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;
+    int ttl;
+} globcfg;
+
+pthread_t pcap_x_thread;
+pthread_t tun_x_thread;
+pthread_t nflog_x_thread;
+
+pthread_attr_t attr;
+pthread_mutex_t lock;
+
+void do_debug(char *msg, ...);
+void my_err(char *msg, ...);
+void my_info(char *msg, ...);
+void switch_state(short action);
+void switch_guard(short action);
+
+void *tun_x(void *x_void_ptr);
+void *nflog_x(void *x_void_ptr);
+void *pcap_x(void *x_void_ptr);
+
+#include "utils.c"
+#include "tun.c"
+#include "pcap.c"
+#include "nflog.c"

src/nflog.c

@@ -1,18 +1,11 @@
 static int callback(struct nflog_g_handle *gh, struct nfgenmsg *nfmsg, struct nflog_data *ldata, void *data)
 {
-    if (status == 0) {
-
+    if (status == OFF) {
         my_info("NFLOG module: executing START command...");
-
-        if (system(globcfg.cmd_path_start) != 0) {
-            my_err("Warning! Executable command doesn't return 0 (%s)", globcfg.cmd_path_start);
-        }
-
-        status = 1;
+        switch_guard(ON);
     }
 
     ts = curts;
-
 }
 
 void *nflog_x(void *x_void_ptr)
@@ -41,7 +34,7 @@ void *nflog_x(void *x_void_ptr)
     }
     qh = nflog_bind_group(h, globcfg.nf_group);
     if (!qh) {
-        my_err("no handle for group 0");
+        my_err("no handle for group %i", globcfg.nf_group);
         exit(1);
     }
 

src/tun.c

@@ -43,6 +43,11 @@ void *tun_x(void *x_void_ptr)
     int nread;
     char buffer[BUFSIZE];
 
+    struct timespec tim;
+
+    tim.tv_sec = 0;
+    tim.tv_nsec = 15000000;
+
 
     if ( (tap_fd = tun_alloc(globcfg.dev_name, globcfg.dev_mode | IFF_NO_PI)) < 0 ) {
         my_err("Fatal error. Connecting to tun/tap interface %s failed.", globcfg.dev_name);
@@ -53,27 +58,21 @@ void *tun_x(void *x_void_ptr)
         nread = cread(tap_fd, buffer, BUFSIZE);
 
         if (globcfg.pcap_filter != NULL) {
-            usleep(15000); //Wait for libpcap timeout.
+            nanosleep(&tim, NULL);
             if ( (curts - ts) < 2 ) {
                 do_debug("Read %d bytes from the tap interface\n", nread);
                 break;
             } 
         } else {
-             break;   
+             break;
         }
     }
 
-    ts = time(NULL);
-
-    status = 1;
-
     close(tap_fd);
 
     my_info("TUN/TAP module: executing START command...");
 
-    if (system(globcfg.cmd_path_start) != 0) {
-        my_err("Warning! Executable command doesn't return 0 (%s)", globcfg.cmd_path_start);
-    }
-
+    switch_guard(ON);
+
     return 0;
 }