1 files changed, 125 insertions, 0 deletions
diff --git a/gsm-receiver/src/lib/decoder/tun.c b/gsm-receiver/src/lib/decoder/tun.c
new file mode 100644
index 0000000..2abda90
--- /dev/null
+++ b/gsm-receiver/src/lib/decoder/tun.c
@@ -0,0 +1,125 @@
+// $Id: tun.cc,v 1.2 2007-07-07 16:31:42 jl Exp $
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <libgen.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <linux/if_tun.h>
+#include <linux/if.h>
+#include <linux/if_ether.h>
+#include <arpa/inet.h>
+
+int mktun(const char *chan_name, unsigned char *ether_addr) {
+
+	struct ifreq ifr;
+	// struct ifreq ifw;
+	char if_name[IFNAMSIZ];
+	int fd, one = 1;
+	// int sd;
+
+	// construct TUN interface
+	if((fd = open("/dev/net/tun", O_RDWR)) == -1) {
+		perror("open");
+		return -1;
+	}
+	memset(&ifr, 0, sizeof(ifr));
+	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+	snprintf(ifr.ifr_name, IFNAMSIZ, "%s", chan_name);
+	if(ioctl(fd, TUNSETIFF, (void *)&ifr) == -1) {
+		perror("TUNSETIFF");
+		close(fd);
+		return -1;
+	}
+
+	// save actual name
+	memcpy(if_name, ifr.ifr_name, IFNAMSIZ);
+
+	// get ether addr
+	memset(&ifr, 0, sizeof(ifr));
+	memcpy(ifr.ifr_name, if_name, IFNAMSIZ);
+	if(ioctl(fd, SIOCGIFHWADDR, (void *)&ifr) == -1) {
+		perror("SIOCGIFHWADDR");
+		close(fd);
+		return -1;
+	}
+	memcpy(ether_addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
+
+	// set persistent
+	if(ioctl(fd, TUNSETPERSIST, (void *)&one) == -1) {
+		perror("TUNSETPERSIST");
+		close(fd);
+		return -1;
+	}
+
+	// set interface up
+	/* XXX must be root
+	if((sd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
+		perror("socket");
+		close(fd);
+		return -1;
+	}
+
+	// get current flags
+	memset(&ifr, 0, sizeof(ifr));
+	strncpy(ifr.ifr_name, if_name, IFNAMSIZ - 1);
+	if(ioctl(sd, SIOCGIFFLAGS, &ifr) == -1) {
+		perror("SIOCGIFFLAGS");
+		close(sd);
+		close(fd);
+		return -1;
+	}
+
+	// set up
+	memset(&ifw, 0, sizeof(ifw));
+	strncpy(ifw.ifr_name, if_name, IFNAMSIZ - 1);
+	ifw.ifr_flags = ifr.ifr_flags | IFF_UP | IFF_RUNNING;
+	if(ioctl(sd, SIOCSIFFLAGS, &ifw) == -1) {
+		perror("SIOCSIFFLAGS");
+		close(sd);
+		close(fd);
+		return -1;
+	}
+	close(sd);
+	 */
+
+	return fd;
+}
+
+
+static inline int min(int a, int b) {
+
+	return (a < b)? a : b;
+}
+
+
+static const unsigned int DEFAULT_MTU = 1500;
+static const unsigned short ether_type = 0xfed5; // current dtap ethertype
+
+int write_interface(int fd, unsigned char *data, unsigned int data_len,
+   unsigned char *ether_addr) {
+
+	unsigned char frame[DEFAULT_MTU]; // XXX buffer overflow?
+	struct ethhdr eh;
+
+	if(fd < 0)
+		return data_len;
+
+	memcpy(eh.h_dest, ether_addr, ETH_ALEN);
+	memcpy(eh.h_source, ether_addr, ETH_ALEN);
+	eh.h_proto = htons(ether_type);
+
+	memcpy(frame, &eh, sizeof(eh));
+	memcpy(frame + sizeof(eh), data,
+	   min(data_len, sizeof(frame) - sizeof(eh)));
+
+	if(write(fd, frame, sizeof(eh) + data_len) == -1) {
+		perror("write");
+		return -1;
+	}
+
+	return data_len;
+}