Constants.h

@@ -6,10 +6,4 @@
 
 #define MTU_MIN 74
 #define MTU_MAX 1522
-#define MTU_DEFAULT 329
-
-#define TXQUEUELEN 10
-
-// ARP timings, in seconds
-#define ARP_BASE_REACHABLE_TIME 300
-#define ARP_RETRANS_TIME 5
+#define MTU_DEFAULT 329

KISS.c

@@ -19,67 +19,67 @@ extern int device_type;
 extern void cleanup(void);
 
 void kiss_frame_received(int frame_len) {
-    if ( (device_type == IF_TUN && frame_len >= TUN_MIN_FRAME_SIZE) || (device_type == IF_TAP && frame_len >= ETHERNET_MIN_FRAME_SIZE) )  {
-        int written = write(attached_if, frame_buffer, frame_len);
-        if (written == -1) {
-            if (verbose && !daemonize) printf("Could not write received KISS frame (%d bytes) to network interface, is the interface up?\r\n", frame_len);
-        } else if (written != frame_len) {
-            if (!daemonize) printf("Error: Could only write %d of %d bytes to interface", written, frame_len);
-            cleanup();
-            exit(1);
-        }
-        if (verbose && !daemonize) printf("Got %d bytes from TNC, wrote %d bytes to interface\r\n", frame_len, written);
-    }
+	if ( (device_type == IF_TUN && frame_len >= TUN_MIN_FRAME_SIZE) || (device_type == IF_TAP && frame_len >= ETHERNET_MIN_FRAME_SIZE) )  {
+		int written = write(attached_if, frame_buffer, frame_len);
+		if (written == -1) {
+			if (verbose && !daemonize) printf("Could not write received KISS frame (%d bytes) to network interface, is the interface up?\r\n", frame_len);
+		} else if (written != frame_len) {
+			if (!daemonize) printf("Error: Could only write %d of %d bytes to interface", written, frame_len);
+			cleanup();
+			exit(1);
+		}
+		if (verbose && !daemonize) printf("Got %d bytes from TNC, wrote %d bytes to interface\r\n", frame_len, written);
+	}
 }
 
 void kiss_serial_read(uint8_t sbyte) {
-    if (IN_FRAME && sbyte == FEND && kiss_command == CMD_DATA) {
-        IN_FRAME = false;
-        kiss_frame_received(frame_len);
-    } else if (sbyte == FEND) {
-        IN_FRAME = true;
-        kiss_command = CMD_UNKNOWN;
-        frame_len = 0;
-    } else if (IN_FRAME && frame_len < MAX_PAYLOAD) {
-        // Have a look at the command byte first
-        if (frame_len == 0 && kiss_command == CMD_UNKNOWN) {
-            // Strip of port nibble
-            kiss_command = sbyte & 0x0F;
-        } else if (kiss_command == CMD_DATA) {
-            if (sbyte == FESC) {
-                ESCAPE = true;
-            } else {
-                if (ESCAPE) {
-                    if (sbyte == TFEND) sbyte = FEND;
-                    if (sbyte == TFESC) sbyte = FESC;
-                    ESCAPE = false;
-                }
+	if (IN_FRAME && sbyte == FEND && kiss_command == CMD_DATA) {
+	    IN_FRAME = false;
+	    kiss_frame_received(frame_len);
+	} else if (sbyte == FEND) {
+	    IN_FRAME = true;
+	    kiss_command = CMD_UNKNOWN;
+	    frame_len = 0;
+	} else if (IN_FRAME && frame_len < MAX_PAYLOAD) {
+	    // Have a look at the command byte first
+	    if (frame_len == 0 && kiss_command == CMD_UNKNOWN) {
+	    	// Strip of port nibble
+	        kiss_command = sbyte & 0x0F;
+	    } else if (kiss_command == CMD_DATA) {
+	        if (sbyte == FESC) {
+	            ESCAPE = true;
+	        } else {
+	            if (ESCAPE) {
+	                if (sbyte == TFEND) sbyte = FEND;
+	                if (sbyte == TFESC) sbyte = FESC;
+	                ESCAPE = false;
+	            }
 
-                if (frame_len < MAX_PAYLOAD) {
-                    frame_buffer[frame_len++] = sbyte;
-                }
-            }
-        }
-    }
+	            if (frame_len < MAX_PAYLOAD) {
+	            	frame_buffer[frame_len++] = sbyte;
+	            }
+	        }
+	    }
+	}
 }
 
 int kiss_write_frame(int serial_port, uint8_t* buffer, int frame_len) {
-    int write_len = 0;
-    write_buffer[write_len++] = FEND;
-    write_buffer[write_len++] = CMD_DATA;
-    for (int i = 0; i < frame_len; i++) {
-        uint8_t byte = buffer[i];
-        if (byte == FEND) {
-            write_buffer[write_len++] = FESC;
-            write_buffer[write_len++] = TFEND;
-        } else if (byte == FESC) {
-            write_buffer[write_len++] = FESC;
-            write_buffer[write_len++] = TFESC;
-        } else {
-            write_buffer[write_len++] = byte;
-        }
-    }
-    write_buffer[write_len++] = FEND;
+	int write_len = 0;
+	write_buffer[write_len++] = FEND;
+	write_buffer[write_len++] = CMD_DATA;
+	for (int i = 0; i < frame_len; i++) {
+		uint8_t byte = buffer[i];
+		if (byte == FEND) {
+			write_buffer[write_len++] = FESC;
+			write_buffer[write_len++] = TFEND;
+		} else if (byte == FESC) {
+			write_buffer[write_len++] = FESC;
+			write_buffer[write_len++] = TFESC;
+		} else {
+			write_buffer[write_len++] = byte;
+		}
+	}
+	write_buffer[write_len++] = FEND;
 
-    return write(serial_port, write_buffer, write_len);
+	return write(serial_port, write_buffer, write_len);
 }

README.md

@@ -6,7 +6,7 @@ Attach KISS TNC devices as network interfaces in Linux. This program allows you
 
 Currently it is recommended to compile and install __tncattach__ from source with the below commands.
 
-If that is not possible for you, precompiled __amd64__ and __armhf__ (Raspberry Pi and similar) binaries have been provided in the releases section. You can [download the latest release here](https://github.com/markqvist/tncattach/releases).
+If that is not possible for you, precompiled __amd64__ and __armhf__ (Raspberry Pi and similar) binaries have been provided in the releases section. You can [download the latest release here](https://github.com/markqvist/tncattach/releases/tag/0.1.3).
 
 ```sh
 # If you don't already have a compiler installed
@@ -34,17 +34,14 @@ Usage: tncattach [OPTION...] port baudrate
 
 Attach TNC devices as system network interfaces
 
-  -m, --mtu=MTU              Specify interface MTU
+  -d, --daemon               Run tncattach as a daemon
   -e, --ethernet             Create a full ethernet device
   -i, --ipv4=IP_ADDRESS      Configure an IPv4 address on interface
+  -m, --mtu=MTU              Specify interface MTU
   -n, --noipv6               Filter IPv6 traffic from reaching TNC
       --noup                 Only create interface, don't bring it up
-  -T, --kisstcp              Use KISS over TCP instead of serial port
-  -H, --tcphost=TCP_HOST     Host to connect to when using KISS over TCP
-  -P, --tcpport=TCP_PORT     TCP port when using KISS over TCP
-  -t, --interval=SECONDS     Maximum interval between station identifications
   -s, --id=CALLSIGN          Station identification data
-  -d, --daemon               Run tncattach as a daemon
+  -t, --interval=SECONDS     Maximum interval between station identifications
   -v, --verbose              Enable verbose output
   -?, --help                 Give this help list
       --usage                Give a short usage message
@@ -53,8 +50,6 @@ Attach TNC devices as system network interfaces
 
 The program supports attaching TNCs as point-to-point tunnel devices, or generic ethernet devices. The ethernet mode is suitable for point-to-multipoint setups, and can be enabled with the corresponding command line switch. If you only need point-to-point links, it is advisable to just use the standard point-to-point mode, since it doesn't incur the ethernet header overhead on each packet.
 
-If you want to connect to a virtual KISS TNC over a TCP connection, you can use the -T option, along with the -H and -P options to specify the host and port.
-
 Additionally, it is worth noting that __tncattach__ can filter out IPv6 packets from reaching the TNC. Most operating systems attempts to autoconfigure IPv6 when an interface is brought up, which results in a substantial amount of IPv6 traffic generated by router solicitations and similar, which is usually unwanted for packet radio links and similar.
 
 If you intend to use __tncattach__ on a system with mDNS services enabled (avahi-daemon, for example), you may want to consider modifying your mDNS setup to exclude TNC interfaces, or turning it off entirely, since it will generate a lot of traffic that might be unwanted.
@@ -80,13 +75,6 @@ Create an ethernet device with a USB-connected TNC, set the MTU, filter IPv6 tra
 sudo tncattach /dev/ttyUSB0 115200 --ethernet --mtu 576 --noipv6 --ipv4 10.92.0.10/24
 ```
 
-Create an ethernet device with a TCP-connected TNC, set the MTU, filter IPv6 traffic, and set an IPv4 address:
-
-```sh
-# Attach interface
-sudo tncattach -T -H localhost -P 8001 --ethernet --mtu 576 --noipv6 --ipv4 10.92.0.10/24
-```
-
 You can interact with the interface like any other using the __ip__ or __ifconfig__ utilities:
 
 ```sh
@@ -123,7 +111,6 @@ tnc0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 400
         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
 
 ```
-
 ## Worth Knowing on Raspbian
 
 On some versions of Raspbian (and probably other operating systems), the DHCP client daemon _dhcpcd_ interferes with TNC interfaces, by overriding their MTU and trying to auto-configure link-local addresses. You probably don't want this, and it can be disabled by editing the __/etc/dhcpcd.conf__ file, adding a statement telling _dhcpcd_ to ignore your TNC interface:
@@ -133,11 +120,4 @@ On some versions of Raspbian (and probably other operating systems), the DHCP cl
 # of /etc/dhcpcd.conf to prevent dhcpcd from changing MTU
 
 denyinterfaces tnc0
-```
-
-## Support tncattach development
-You can help support the continued development of open, free and private communications systems by donating via one of the following channels:
-
-- Ethereum: 0x81F7B979fEa6134bA9FD5c701b3501A2e61E897a
-- Bitcoin: 3CPmacGm34qYvR6XWLVEJmi2aNe3PZqUuq
-- Ko-Fi: https://ko-fi.com/markqvist
+```

Serial.c

@@ -3,172 +3,172 @@
 extern void cleanup();
 
 int open_port(char* port) {
-    int fd;
-    fd = open(port, O_RDWR | O_NOCTTY | O_SYNC | O_NDELAY);
+	int fd;
+	fd = open(port, O_RDWR | O_NOCTTY | O_SYNC | O_NDELAY);
 
-    if (fd == -1) {
-        perror("The serial port could not be opened");
-        cleanup();
-        exit(1);
-    } else {
-        fcntl(fd, F_SETFL, 0);
-    }
+	if (fd == -1) {
+		perror("The serial port could not be opened");
+		cleanup();
+		exit(1);
+	} else {
+		fcntl(fd, F_SETFL, 0);
+	}
 
-    return fd;
+	return fd;
 }
 
 int close_port(int fd) {
-    return close(fd);
+	return close(fd);
 }
 
 void set_speed(void *tty_s, int speed) {
-    cfsetospeed(tty_s, speed);
-    cfsetispeed(tty_s, speed);
+	cfsetospeed(tty_s, speed);
+	cfsetispeed(tty_s, speed);
 }
 
 bool setup_port(int fd, int speed) {
-    struct termios tty;
-    if (tcgetattr(fd, &tty) != 0) {
-        perror("Error setting port speed, could not read port parameters");
-        return false;
-    }
+	struct termios tty;
+	if (tcgetattr(fd, &tty) != 0) {
+		perror("Error setting port speed, could not read port parameters");
+		return false;
+	}
 
-    switch (speed) {
-        case 0:
-            set_speed(&tty, B0);
-            break;
-        case 50:
-            set_speed(&tty, B50);
-            break;
-        case 75:
-            set_speed(&tty, B75);
-            break;
-        case 110:
-            set_speed(&tty, B110);
-            break;
-        case 134:
-            set_speed(&tty, B134);
-            break;
-        case 150:
-            set_speed(&tty, B150);
-            break;
-        case 200:
-            set_speed(&tty, B200);
-            break;
-        case 300:
-            set_speed(&tty, B300);
-            break;
-        case 600:
-            set_speed(&tty, B600);
-            break;
-        case 1200:
-            set_speed(&tty, B1200);
-            break;
-        case 2400:
-            set_speed(&tty, B2400);
-            break;
-        case 4800:
-            set_speed(&tty, B4800);
-            break;
-        case 9600:
-            set_speed(&tty, B9600);
-            break;
-        case 19200:
-            set_speed(&tty, B19200);
-            break;
-        case 38400:
-            set_speed(&tty, B38400);
-            break;
-        case 57600:
-            set_speed(&tty, B57600);
-            break;
-        case 115200:
-            set_speed(&tty, B115200);
-            break;
-        case 230400:
-            set_speed(&tty, B230400);
-            break;
-        default:
-            printf("Error: Invalid port speed %d specified\r\n", speed);
-            cleanup();
-            exit(1);
-            return false;
-    }
+	switch (speed) {
+		case 0:
+			set_speed(&tty, B0);
+			break;
+		case 50:
+			set_speed(&tty, B50);
+			break;
+		case 75:
+			set_speed(&tty, B75);
+			break;
+		case 110:
+			set_speed(&tty, B110);
+			break;
+		case 134:
+			set_speed(&tty, B134);
+			break;
+		case 150:
+			set_speed(&tty, B150);
+			break;
+		case 200:
+			set_speed(&tty, B200);
+			break;
+		case 300:
+			set_speed(&tty, B300);
+			break;
+		case 600:
+			set_speed(&tty, B600);
+			break;
+		case 1200:
+			set_speed(&tty, B1200);
+			break;
+		case 2400:
+			set_speed(&tty, B2400);
+			break;
+		case 4800:
+			set_speed(&tty, B4800);
+			break;
+		case 9600:
+			set_speed(&tty, B9600);
+			break;
+		case 19200:
+			set_speed(&tty, B19200);
+			break;
+		case 38400:
+			set_speed(&tty, B38400);
+			break;
+		case 57600:
+			set_speed(&tty, B57600);
+			break;
+		case 115200:
+			set_speed(&tty, B115200);
+			break;
+		case 230400:
+			set_speed(&tty, B230400);
+			break;
+		default:
+			printf("Error: Invalid port speed %d specified\r\n", speed);
+			cleanup();
+			exit(1);
+			return false;
+	}
 
-    // Set 8-bit characters, no parity, one stop bit
-    tty.c_cflag |= CS8;
-    tty.c_cflag &= ~PARENB;
-    tty.c_cflag &= ~CSTOPB;
+	// Set 8-bit characters, no parity, one stop bit
+	tty.c_cflag |= CS8;
+	tty.c_cflag &= ~PARENB;
+	tty.c_cflag &= ~CSTOPB;
 
-    // Disable hardware flow control
-    tty.c_cflag &= ~CRTSCTS;
+	// Disable hardware flow control
+	tty.c_cflag &= ~CRTSCTS;
 
-    // Enable reading and ignore modem
-    // control lines
-    tty.c_cflag |= CREAD | CLOCAL;
+	// Enable reading and ignore modem
+	// control lines
+	tty.c_cflag |= CREAD | CLOCAL;
 
-    // Disable canonical mode, echo
-    // and signal characters.
-    tty.c_lflag &= ~ICANON;
-    tty.c_lflag &= ~ECHO;
-    tty.c_lflag &= ~ECHOE;
-    tty.c_lflag &= ~ECHONL;
-    tty.c_lflag &= ~ISIG;
+	// Disable canonical mode, echo
+	// and signal characters.
+	tty.c_lflag &= ~ICANON;
+	tty.c_lflag &= ~ECHO;
+	tty.c_lflag &= ~ECHOE;
+	tty.c_lflag &= ~ECHONL;
+	tty.c_lflag &= ~ISIG;
 
-    // Disable processing of input,
-    // just pass the raw data.
-    tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL);
+	// Disable processing of input,
+	// just pass the raw data.
+	tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL);
 
-    // Disable XON/XOFF software flow control.
-    tty.c_iflag &= ~(IXON | IXOFF | IXANY);
+	// Disable XON/XOFF software flow control.
+	tty.c_iflag &= ~(IXON | IXOFF | IXANY);
 
-    // Disable processing output bytes
-    // and new line conversions
-    tty.c_oflag &= ~OPOST;
-    tty.c_oflag &= ~ONLCR;
+	// Disable processing output bytes
+	// and new line conversions
+	tty.c_oflag &= ~OPOST;
+	tty.c_oflag &= ~ONLCR;
 
-    // Block forever until at least one byte is read.
-    tty.c_cc[VMIN]   = 1;
-    tty.c_cc[VTIME]  = 0;
+	// Block forever until at least one byte is read.
+	tty.c_cc[VMIN]   = 1;
+	tty.c_cc[VTIME]  = 0;
 
-    // TODO: Check these
-    // Prevent conversion of tabs to spaces (NOT PRESENT IN LINUX)
-    // tty.c_oflag &= ~OXTABS;
-    // Prevent removal of C-d chars (0x004) in output (NOT PRESENT IN LINUX)
-    // tty.c_oflag &= ~ONOEOT;
+	// TODO: Check these
+	// Prevent conversion of tabs to spaces (NOT PRESENT IN LINUX)
+	// tty.c_oflag &= ~OXTABS;
+	// Prevent removal of C-d chars (0x004) in output (NOT PRESENT IN LINUX)
+	// tty.c_oflag &= ~ONOEOT;
 
-    if (tcsetattr(fd, TCSANOW, &tty) != 0) {
-        perror("Could not configure serial port parameters");
-        return false;
-    } else {
-        return true;
-    }
+	if (tcsetattr(fd, TCSANOW, &tty) != 0) {
+		perror("Could not configure serial port parameters");
+		return false;
+	} else {
+		return true;
+	}
 }
 
 bool set_port_blocking(int fd, bool should_block) {
-    struct termios tty;
-    memset(&tty, 0, sizeof tty);
+	struct termios tty;
+	memset(&tty, 0, sizeof tty);
 
-    if (tcgetattr(fd, &tty) != 0) {
-        perror("Error configuring port blocking behaviour, could not read port parameters");
-        return false;
-    } else {
-        // TODO: Implement this correctly
-        if (should_block) {
-            // Block forever until at least one byte is read.
-            tty.c_cc[VMIN]   = 1;
-            tty.c_cc[VTIME]  = 0;
-        } else {
-            // Never block, always return immediately with
-            // whatever is available.
-            tty.c_cc[VMIN]   = 0;
-            tty.c_cc[VTIME]  = 0;
-        }
-        if (tcsetattr(fd, TCSANOW, &tty) != 0) {
-            perror("Could not set port parameters while configuring blocking behaviour");
-            return false;
-        } else {
-            return true;
-        }
-    }
+	if (tcgetattr(fd, &tty) != 0) {
+		perror("Error configuring port blocking behaviour, could not read port parameters");
+		return false;
+	} else {
+		// TODO: Implement this correctly
+		if (should_block) {
+			// Block forever until at least one byte is read.
+			tty.c_cc[VMIN]   = 1;
+			tty.c_cc[VTIME]  = 0;
+		} else {
+			// Never block, always return immediately with
+			// whatever is available.
+			tty.c_cc[VMIN]   = 0;
+			tty.c_cc[VTIME]  = 0;
+		}
+		if (tcsetattr(fd, TCSANOW, &tty) != 0) {
+			perror("Could not set port parameters while configuring blocking behaviour");
+			return false;
+		} else {
+			return true;
+		}
+	}
 }

TAP.c

@@ -15,184 +15,125 @@ extern char* netmask;
 extern void cleanup();
 
 int open_tap(void) {
-    struct ifreq ifr;
-    int fd = open("/dev/net/tun", O_RDWR);
+	struct ifreq ifr;
+	int fd = open("/dev/net/tun", O_RDWR);
 
-    if (fd < 0) {
-        perror("Could not open clone device");
-        exit(1);
-    } else {
-        memset(&ifr, 0, sizeof(ifr));
-        // TODO: Enable PI header again?
+	if (fd < 0) {
+		perror("Could not open clone device");
+		exit(1);
+	} else {
+		memset(&ifr, 0, sizeof(ifr));
+		// TODO: Enable PI header again?
 
-        if (device_type == IF_TAP) {
-            ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
-        } else if (device_type == IF_TUN) {
-            ifr.ifr_flags = IFF_TUN;
-        } else {
-            printf("Error: Unsupported interface type\r\n");
-            cleanup();
-            exit(1);
-        }
+		if (device_type == IF_TAP) {
+			ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+		} else if (device_type == IF_TUN) {
+			ifr.ifr_flags = IFF_TUN;
+		} else {
+			printf("Error: Unsupported interface type\r\n");
+			cleanup();
+			exit(1);
+		}
 
-        strcpy(tap_name, "tnc%d");
-        strncpy(ifr.ifr_name, tap_name, IFNAMSIZ);
+		strcpy(tap_name, "tnc%d");
+		strncpy(ifr.ifr_name, tap_name, IFNAMSIZ);
 
-        if (ioctl(fd, TUNSETIFF, &ifr) < 0) {
-            perror("Could not configure network interface");
-            exit(1);
-        } else {
-            strcpy(if_name, ifr.ifr_name);
-            
-            int inet = socket(AF_INET, SOCK_DGRAM, 0);
-            if (inet == -1) {
-                perror("Could not open AF_INET socket");
-                cleanup();
-                exit(1);
-            } else {
-                if (ioctl(inet, SIOCGIFMTU, &ifr) < 0) {
-                    perror("Could not get interface flags from kernel");
-                    close(inet);
-                    cleanup();
-                    exit(1);
-                } else {
-                    ifr.ifr_mtu = mtu;
-                    if (ioctl(inet, SIOCSIFMTU, &ifr) < 0) {
-                        perror("Could not configure interface MTU");
-                        close(inet);
-                        cleanup();
-                        exit(1);
-                    }
+		if (ioctl(fd, TUNSETIFF, &ifr) < 0) {
+			perror("Could not configure network interface");
+			exit(1);
+		} else {
+			strcpy(if_name, ifr.ifr_name);
+			
+			int inet = socket(AF_INET, SOCK_DGRAM, 0);
+			if (inet == -1) {
+				perror("Could not open AF_INET socket\r\n");
+				cleanup();
+				exit(1);
+			} else {
+				if (ioctl(inet, SIOCGIFMTU, &ifr) < 0) {
+					perror("Could not get interface flags from kernel");
+					close(inet);
+					cleanup();
+					exit(1);
+				} else {
+					ifr.ifr_mtu = mtu;
+					if (ioctl(inet, SIOCSIFMTU, &ifr) < 0) {
+						perror("Could not configure interface MTU");
+						close(inet);
+						cleanup();
+						exit(1);
+					}
 
-                    // Configure TX queue length
-                    if (ioctl(inet, SIOCGIFTXQLEN, &ifr) < 0) {
-                        perror("Could not get interface flags from kernel");
-                        close(inet);
-                        cleanup();
-                        exit(1);
-                    } else {
-                        ifr.ifr_qlen = TXQUEUELEN;
-                        if (ioctl(inet, SIOCSIFTXQLEN, &ifr) < 0) {
-                            perror("Could not set interface TX queue length");
-                            close(inet);
-                            cleanup();
-                            exit(1);
-                        }
-                    }
+					if (!noup) {
+						if (ioctl(inet, SIOCGIFFLAGS, &ifr) < 0) {
+							perror("Could not get interface flags from kernel");
+							close(inet);
+							cleanup();
+							exit(1);
+						} else {
+							ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
+							if (ioctl(inet, SIOCSIFFLAGS, &ifr) < 0) {
+								perror("Could not bring up interface");
+								close(inet);
+								cleanup();
+								exit(1);
+							} else {
+								if (set_ipv4) {
+									struct ifreq a_ifr;
+									struct sockaddr_in addr, snm;
 
-                    // Configure ARP characteristics
-                    char path_buf[256];
-                    if (device_type == IF_TAP) {
-                        snprintf(path_buf, sizeof(path_buf), "/proc/sys/net/ipv4/neigh/%s/base_reachable_time_ms", ifr.ifr_name);
-                        int arp_fd = open(path_buf, O_WRONLY);
-                        if (arp_fd < 0) {
-                            perror("Could not open proc entry for ARP parameters");
-                            close(inet);
-                            cleanup();
-                            exit(1);
-                        } else {
-                            if (dprintf(arp_fd, "%d", ARP_BASE_REACHABLE_TIME*1000) <= 0) {
-                                perror("Could not configure interface ARP parameter base_reachable_time_ms");
-                                close(inet);
-                                close(arp_fd);
-                                cleanup();
-                                exit(1);
-                            } else {
-                                close(arp_fd);
-                            }
-                        }
+									memset(&a_ifr, 0, sizeof(a_ifr));
+									memset(&addr, 0, sizeof(addr));
+									memset(&snm, 0, sizeof(addr));
+									strncpy(a_ifr.ifr_name, ifr.ifr_name, IFNAMSIZ);
+									addr.sin_family = AF_INET;
+									snm.sin_family = AF_INET;
 
-                        snprintf(path_buf, sizeof(path_buf), "/proc/sys/net/ipv4/neigh/%s/retrans_time_ms", ifr.ifr_name);
-                        arp_fd = open(path_buf, O_WRONLY);
-                        if (arp_fd < 0) {
-                            perror("Could not open proc entry for ARP parameters");
-                            close(inet);
-                            cleanup();
-                            exit(1);
-                        } else {
-                            if (dprintf(arp_fd, "%d", ARP_RETRANS_TIME*1000) <= 0) {
-                                perror("Could not configure interface ARP parameter retrans_time_ms");
-                                close(inet);
-                                close(arp_fd);
-                                cleanup();
-                                exit(1);
-                            } else {
-                                close(arp_fd);
-                            }
-                        }
-                    }
+									int addr_conversion = inet_pton(AF_INET, ipv4_addr, &(addr.sin_addr));
+									if (addr_conversion != 1) {
+										printf("Error: Invalid IPv4 address specified\r\n");
+										close(inet);
+										cleanup();
+										exit(1);
+									} else {
+										a_ifr.ifr_addr = *(struct sockaddr*)&addr;
+										if (ioctl(inet, SIOCSIFADDR, &a_ifr) < 0) {
+											perror("Could not set IP-address");
+											close(inet);
+											cleanup();
+											exit(1);
+										} else {
+											if (set_netmask) {
+												int snm_conversion = inet_pton(AF_INET, netmask, &(snm.sin_addr));
+												if (snm_conversion != 1) {
+													printf("Error: Invalid subnet mask specified\r\n");
+													close(inet);
+													cleanup();
+													exit(1);
+												} else {
+													a_ifr.ifr_addr = *(struct sockaddr*)&snm;
+													if (ioctl(inet, SIOCSIFNETMASK, &a_ifr) < 0) {
+														perror("Could not set subnet mask");
+														close(inet);
+														cleanup();
+														exit(1);
+													}
+												}
+											}
+										}
+									}
+								}
+							}
+						}
+					}
+				}
+			}
 
-                    // Bring up if requested
-                    if (!noup) {
-                        if (ioctl(inet, SIOCGIFFLAGS, &ifr) < 0) {
-                            perror("Could not get interface flags from kernel");
-                            close(inet);
-                            cleanup();
-                            exit(1);
-                        } else {
-                            ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
-                            if (ioctl(inet, SIOCSIFFLAGS, &ifr) < 0) {
-                                perror("Could not bring up interface");
-                                close(inet);
-                                cleanup();
-                                exit(1);
-                            } else {
-                                if (set_ipv4) {
-                                    struct ifreq a_ifr;
-                                    struct sockaddr_in addr, snm;
-
-                                    memset(&a_ifr, 0, sizeof(a_ifr));
-                                    memset(&addr, 0, sizeof(addr));
-                                    memset(&snm, 0, sizeof(addr));
-                                    strncpy(a_ifr.ifr_name, ifr.ifr_name, IFNAMSIZ);
-                                    addr.sin_family = AF_INET;
-                                    snm.sin_family = AF_INET;
-
-                                    int addr_conversion = inet_pton(AF_INET, ipv4_addr, &(addr.sin_addr));
-                                    if (addr_conversion != 1) {
-                                        printf("Error: Invalid IPv4 address specified\r\n");
-                                        close(inet);
-                                        cleanup();
-                                        exit(1);
-                                    } else {
-                                        a_ifr.ifr_addr = *(struct sockaddr*)&addr;
-                                        if (ioctl(inet, SIOCSIFADDR, &a_ifr) < 0) {
-                                            perror("Could not set IP-address");
-                                            close(inet);
-                                            cleanup();
-                                            exit(1);
-                                        } else {
-                                            if (set_netmask) {
-                                                int snm_conversion = inet_pton(AF_INET, netmask, &(snm.sin_addr));
-                                                if (snm_conversion != 1) {
-                                                    printf("Error: Invalid subnet mask specified\r\n");
-                                                    close(inet);
-                                                    cleanup();
-                                                    exit(1);
-                                                } else {
-                                                    a_ifr.ifr_addr = *(struct sockaddr*)&snm;
-                                                    if (ioctl(inet, SIOCSIFNETMASK, &a_ifr) < 0) {
-                                                        perror("Could not set subnet mask");
-                                                        close(inet);
-                                                        cleanup();
-                                                        exit(1);
-                                                    }
-                                                }
-                                            }
-                                        }
-                                    }
-                                }
-                            }
-                        }
-                    }
-                }
-            }
-
-            return fd;
-        }
-    }
+			return fd;
+		}
+	}
 }
 
 int close_tap(int tap_fd) {
-    return close(tap_fd);
+	return close(tap_fd);
 }

TCP.c

@@ -1,37 +0,0 @@
-#include "TCP.h"
-
-int open_tcp(char* ip, int port) {
-    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
-
-    if (sockfd < 0) {
-        perror("Could not open AF_INET socket");
-        exit(1);
-    }
-
-    struct hostent *server;
-    struct sockaddr_in serv_addr;
-
-    server = gethostbyname(ip);
-
-    if (server == NULL) {
-        perror("Error resolving host");
-        exit(1);
-    }
-
-    memset(&serv_addr, 0, sizeof(serv_addr)); 
-    serv_addr.sin_family = AF_INET;
-
-    memcpy(server->h_addr, &serv_addr.sin_addr.s_addr, server->h_length);
-    serv_addr.sin_port = htons(port);
-
-    if (connect(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0) {
-        perror("Could not connect TCP socket");
-        exit(1);
-    }
-
-    return sockfd;
-}
-
-int close_tcp(int fd) {
-    return close(fd);
-}

TCP.h

@@ -1,9 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdbool.h>
-#include <string.h>
-#include <unistd.h>
-#include <netdb.h>
-
-int open_tcp(char* ip, int port);
-int close_tcp(int fd);

makefile

@@ -1,35 +1,26 @@
 .DEFAULT_GOAL := all
 .PHONY: all clean install uninstall tncattach
 
-RM ?= rm
-INSTALL ?= install
-CC ?= gcc
-CFLAGS ?= -Wall -std=gnu11 -static-libgcc
-LDFLAGS ?= 
-PREFIX ?= /usr/local
+compiler = gcc
+flags = -std=gnu11 -lm
 
 all: tncattach
 rebuild: clean all
 
 clean:
 	@echo "Cleaning tncattach build..."
-	$(RM) -f tncattach
+	@rm -f tncattach
 
 tncattach:
 	@echo "Making tncattach..."
-	@echo "Compiling with: $(CC)"
-	$(CC) $(CFLAGS) $(LDFLAGS) tncattach.c Serial.c TCP.c KISS.c TAP.c -o tncattach
+	@echo "Compiling with: ${compiler}"
+	${compiler} ${flags} tncattach.c Serial.c KISS.c TAP.c -o tncattach -Wall
 
 install:
 	@echo "Installing tncattach..."
-	$(INSTALL) -d $(DESTDIR)/$(PREFIX)/bin
-	$(INSTALL) -Dm755 tncattach $(DESTDIR)/$(PREFIX)/bin/tncattach
-	@echo "Installing man page..."
-	gzip -9 tncattach.8
-	$(INSTALL) -d $(DESTDIR)/$(PREFIX)/share/man/man8
-	$(INSTALL) -Dm644 tncattach.8.gz $(DESTDIR)/$(PREFIX)/share/man/man8/tncattach.8.gz
+	chmod a+x tncattach
+	cp ./tncattach /usr/local/sbin/
 
 uninstall:
 	@echo "Uninstalling tncattach"
-	$(RM) $(DESTDIR)/$(PREFIX)/bin/tncattach
-	$(RM) $(DESTDIR)/$(PREFIX)/share/man/man8/tncattach.8.gz
+	rm /usr/local/sbin/tncattach

tncattach.8

@@ -1,165 +0,0 @@
-.TH tncattach 8 "September 12, 2020"
-
-.SH NAME
-.
-.
-tncattach \- Attach TNC devices as system network interfaces
-
-.SH SYNOPSIS
-.
-.
-\f[B]tncattach\f[R] [OPTION...] port baudrate
-
-.SH DESCRIPTION
-Attach KISS TNC devices as network interfaces in Linux. This program allows you to attach TNCs or any KISS-compatible device as a network interface. This program does not need any kernel modules, and has no external dependencies outside the standard Linux and GNU C libraries.
-
-.SH OPTIONS
-.
-.
-.TP
-.BI \-m, \-\-mtu=MTU
-.
-Specify interface MTU
-.
-.
-.TP
-.BI \-e, \-\-ethernet
-Create a full ethernet device
-.
-.
-.TP
-.BI \-i, \-\-ipv4=IP_ADDRESS
-Configure an IPv4 address on interface
-.
-.
-.TP
-.BI \-n, \-\-noipv6
-Filter IPv6 traffic from reaching TNC
-.
-.
-.TP
-.BI \-\-noup
-Only create interface, don't bring it up
-.
-.
-.TP
-.BI \-T, \-\-kisstcp
-Use KISS over TCP instead of serial port
-.
-.
-.TP
-.BI \-H, \-\-tcphost=TCP_HOST
-Host to connect to when using KISS over TCP
-.
-.
-.TP
-.BI \-P, \-\-tcpport=TCP_PORT
-TCP port when using KISS over TCP
-.
-.
-.TP
-.BI \-t, \-\-interval=SECONDS
-Maximum interval between station identifications
-.
-.
-.TP
-.B \-s, \-\-id=CALLSIGN
-Station identification data
-.
-.
-.TP
-.BI \-d, \-\-daemon
-Run tncattach as a daemon
-.
-.
-.TP
-.BI \-v, \-\-verbose
-Enable verbose output
-.
-.
-.TP
-.BI \-?, \-\-help
-Show help
-.
-.
-.TP
-.BI \-\-usage
-Give a short usage message
-.
-.
-.TP
-.BI \-V, \-\-version
-Print program version
-.
-.
-
-.SH USAGE
-The program supports attaching TNCs as point-to-point tunnel devices, or generic ethernet devices. The ethernet mode is suitable for point-to-multipoint setups, and can be enabled with the corresponding command line switch. If you only need point-to-point links, it is advisable to just use the standard point-to-point mode, since it doesn't incur the ethernet header overhead on each packet.
-.P
-If you want to connect to a virtual KISS TNC over a TCP connection, you can use the -T option, along with the -H and -P options to specify the host and port.
-.P
-Additionally, it is worth noting that tncattach can filter out IPv6 packets from reaching the TNC. Most operating systems attempts to autoconfigure IPv6 when an interface is brought up, which results in a substantial amount of IPv6 traffic generated by router solicitations and similar, which is usually unwanted for packet radio links and similar.
-.P
-If you intend to use tncattach on a system with mDNS services enabled (avahi-daemon, for example), you may want to consider modifying your mDNS setup to exclude TNC interfaces, or turning it off entirely, since it will generate a lot of traffic that might be unwanted.
-
-.SH STATION IDENTIFICATION
-
-You can configure tncattach to automatically transmit station identification beacons according to a given interval, by using the --id and --interval options. Identification will be transmitted as raw data frames with whatever content has been specified in the --id option. Useful for amateur radio use, or other areas where station identification is necessary.
-.P
-Identification beacons will be transmitted when:
-.P
-.IP
-There is outgoing data to send, and the specified interval has elapsed.
-.IP
-The specified interval elapses, and data has been sent since the last ID beacon.
-.IP
-The program exits, if any data frames have been transmitted since the last ID beacon.
-.P
-The above methodology should comply with station identification rules for amateur radio in most parts of the world, and complies with US Part 97 rules.
-
-.SH EXAMPLES
-.
-Create an ethernet device with a USB-connected TNC, set the MTU, filter IPv6 traffic, and set an IPv4 address:
-.IP
-sudo tncattach /dev/ttyUSB0 115200 --ethernet --mtu 576 --noipv6 --ipv4 10.92.0.10/24
-.P
-Create an ethernet device with a TCP-connected TNC, set the MTU, filter IPv6 traffic, and set an IPv4 address:
-.IP
-sudo tncattach -T -H localhost -P 8001 --ethernet --mtu 576 --noipv6 --ipv4 10.92.0.10/24
-.P
-You can interact with the interface like any other using the ip or ifconfig utilities.
-.p
-Check interface is running:
-.P
-# ifconfig
-.br
-tnc0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 400
-.br
-        inet 10.93.0.1  netmask 255.255.255.255  destination 10.93.0.2
-.br
-        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 500  (UNSPEC)
-.br
-        RX packets 0  bytes 0 (0.0 B)
-.br
-        RX errors 0  dropped 0  overruns 0  frame 0
-.br
-        TX packets 0  bytes 0 (0.0 B)
-.br
-        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
-.P
-.SH WORTH KNOWING ON RASPBIAN
-On some versions of Raspbian (and probably other operating systems), the DHCP client daemon dhcpcd interferes with TNC interfaces, by overriding their MTU and trying to auto-configure link-local addresses. You probably don't want this, and it can be disabled by editing the /etc/dhcpcd.conf file, adding a statement telling dhcpcd to ignore your TNC interface:
-.P
-# Add the following statement somewhere at the beginning
-.br
-# of /etc/dhcpcd.conf to prevent dhcpcd from changing MTU
-.br
-denyinterfaces tnc0
-
-.SH SEE ALSO
-
-rnodeconfigutil(8)
-
-.SH AUTHOR
-
-Mark Qvist