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198 lines
8.3 KiB
198 lines
8.3 KiB
#include "TAP.h"
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char tap_name[IFNAMSIZ];
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extern bool verbose;
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extern bool noipv6;
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extern bool set_ipv4;
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extern bool set_netmask;
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extern bool noup;
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extern int mtu;
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extern int device_type;
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extern char if_name[IFNAMSIZ];
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extern char* ipv4_addr;
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extern char* netmask;
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extern void cleanup();
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int open_tap(void) {
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struct ifreq ifr;
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int fd = open("/dev/net/tun", O_RDWR);
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if (fd < 0) {
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perror("Could not open clone device");
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exit(1);
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} else {
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memset(&ifr, 0, sizeof(ifr));
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// TODO: Enable PI header again?
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if (device_type == IF_TAP) {
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ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
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} else if (device_type == IF_TUN) {
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ifr.ifr_flags = IFF_TUN;
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} else {
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printf("Error: Unsupported interface type\r\n");
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cleanup();
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exit(1);
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}
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strcpy(tap_name, "tnc%d");
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strncpy(ifr.ifr_name, tap_name, IFNAMSIZ);
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if (ioctl(fd, TUNSETIFF, &ifr) < 0) {
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perror("Could not configure network interface");
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exit(1);
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} else {
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strcpy(if_name, ifr.ifr_name);
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int inet = socket(AF_INET, SOCK_DGRAM, 0);
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if (inet == -1) {
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perror("Could not open AF_INET socket");
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cleanup();
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exit(1);
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} else {
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if (ioctl(inet, SIOCGIFMTU, &ifr) < 0) {
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perror("Could not get interface flags from kernel");
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close(inet);
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cleanup();
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exit(1);
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} else {
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ifr.ifr_mtu = mtu;
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if (ioctl(inet, SIOCSIFMTU, &ifr) < 0) {
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perror("Could not configure interface MTU");
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close(inet);
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cleanup();
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exit(1);
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}
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// Configure TX queue length
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if (ioctl(inet, SIOCGIFTXQLEN, &ifr) < 0) {
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perror("Could not get interface flags from kernel");
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close(inet);
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cleanup();
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exit(1);
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} else {
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ifr.ifr_qlen = TXQUEUELEN;
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if (ioctl(inet, SIOCSIFTXQLEN, &ifr) < 0) {
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perror("Could not set interface TX queue length");
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close(inet);
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cleanup();
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exit(1);
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}
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}
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// Configure ARP characteristics
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char path_buf[256];
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if (device_type == IF_TAP) {
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snprintf(path_buf, sizeof(path_buf), "/proc/sys/net/ipv4/neigh/%s/base_reachable_time_ms", ifr.ifr_name);
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int arp_fd = open(path_buf, O_WRONLY);
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if (arp_fd < 0) {
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perror("Could not open proc entry for ARP parameters");
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close(inet);
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cleanup();
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exit(1);
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} else {
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if (dprintf(arp_fd, "%d", ARP_BASE_REACHABLE_TIME*1000) <= 0) {
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perror("Could not configure interface ARP parameter base_reachable_time_ms");
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close(inet);
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close(arp_fd);
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cleanup();
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exit(1);
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} else {
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close(arp_fd);
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}
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}
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snprintf(path_buf, sizeof(path_buf), "/proc/sys/net/ipv4/neigh/%s/retrans_time_ms", ifr.ifr_name);
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arp_fd = open(path_buf, O_WRONLY);
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if (arp_fd < 0) {
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perror("Could not open proc entry for ARP parameters");
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close(inet);
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cleanup();
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exit(1);
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} else {
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if (dprintf(arp_fd, "%d", ARP_RETRANS_TIME*1000) <= 0) {
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perror("Could not configure interface ARP parameter retrans_time_ms");
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close(inet);
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close(arp_fd);
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cleanup();
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exit(1);
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} else {
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close(arp_fd);
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}
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}
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}
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// Bring up if requested
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if (!noup) {
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if (ioctl(inet, SIOCGIFFLAGS, &ifr) < 0) {
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perror("Could not get interface flags from kernel");
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close(inet);
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cleanup();
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exit(1);
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} else {
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ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
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if (ioctl(inet, SIOCSIFFLAGS, &ifr) < 0) {
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perror("Could not bring up interface");
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close(inet);
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cleanup();
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exit(1);
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} else {
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if (set_ipv4) {
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struct ifreq a_ifr;
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struct sockaddr_in addr, snm;
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memset(&a_ifr, 0, sizeof(a_ifr));
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memset(&addr, 0, sizeof(addr));
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memset(&snm, 0, sizeof(addr));
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strncpy(a_ifr.ifr_name, ifr.ifr_name, IFNAMSIZ);
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addr.sin_family = AF_INET;
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snm.sin_family = AF_INET;
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int addr_conversion = inet_pton(AF_INET, ipv4_addr, &(addr.sin_addr));
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if (addr_conversion != 1) {
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printf("Error: Invalid IPv4 address specified\r\n");
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close(inet);
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cleanup();
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exit(1);
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} else {
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a_ifr.ifr_addr = *(struct sockaddr*)&addr;
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if (ioctl(inet, SIOCSIFADDR, &a_ifr) < 0) {
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perror("Could not set IP-address");
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close(inet);
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cleanup();
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exit(1);
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} else {
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if (set_netmask) {
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int snm_conversion = inet_pton(AF_INET, netmask, &(snm.sin_addr));
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if (snm_conversion != 1) {
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printf("Error: Invalid subnet mask specified\r\n");
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close(inet);
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cleanup();
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exit(1);
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} else {
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a_ifr.ifr_addr = *(struct sockaddr*)&snm;
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if (ioctl(inet, SIOCSIFNETMASK, &a_ifr) < 0) {
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perror("Could not set subnet mask");
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close(inet);
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cleanup();
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exit(1);
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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return fd;
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}
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}
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}
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int close_tap(int tap_fd) {
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return close(tap_fd);
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} |