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-rw-r--r--src/lib/decoder/tun.c125
1 files changed, 125 insertions, 0 deletions
diff --git a/src/lib/decoder/tun.c b/src/lib/decoder/tun.c
new file mode 100644
index 0000000..2abda90
--- /dev/null
+++ b/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;
+}
personal git repositories of Harald Welte. Your mileage may vary