- tun/tap support for ax25ipd

	- fclose() fix in config.c

	description of tun/tap:
	added a new fast and efficient link to the linux kernel ax25 stack,
	via the ethertap interface.
	ax25 goes directly to the bpqether interface in the kernel via
	ethertap/tuntap interfaces, which is a much better way than traditional
	kissattach to a ttyp/ptyp pair.

1 files changed, 342 insertions, 0 deletions

diff --git a/ax25ipd/bpqether.c b/ax25ipd/bpqether.c
new file mode 100644
index 0000000..58333f1
--- /dev/null
+++ b/ax25ipd/bpqether.c
@@ -0,0 +1,342 @@
+/* @(#) $Id: bpqether.c,v 1.1 2005/10/30 10:31:40 dl9sau Exp $ */
+
+extern int ttyfd;
+/*
+ * this is a port of wampes ethertap whith my extension for bpqether
+ *
+ * (c) 20020630 Thomas Osterried  dl9sau
+ * License: GPL
+ */
+
+#include <sys/types.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <syslog.h>
+
+#ifdef  linux
+
+#include <linux/version.h>
+#ifndef KERNEL_VERSION
+#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
+#endif
+#ifndef LINUX_VERSION_CODE
+#define LINUX_VERSION_CODE KERNEL_VERSION(2,4,0)-1
+#endif
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
+#define TRY_TUNTAP 1
+#include <net/if.h>
+#include <linux/if_tun.h>
+#else
+#include <linux/if.h>
+#endif
+
+#endif /* linux */
+
+#include "ax25ipd.h"
+
+#define ETAP_MTU_MIN    256
+#define ETAP_MTU        1024
+#define ETAP_MTU_MAX    1500
+#ifndef	MAX_FRAME
+#define MAX_FRAME       2048
+#endif
+
+#define ETHERTAP_HEADER_LEN_TUN		18
+#define ETHERTAP_HEADER_LEN_ETHERTAP	16
+#define	ETHERTAP_HEADER_LEN_MAX	ETHERTAP_HEADER_LEN_TUN
+
+struct ethertap_packet {
+  char ethernet_header[18];
+  char data[MAX_FRAME];
+};
+
+unsigned char hwaddr_remote[6];
+
+static int ethertap_header_len;
+
+/*---------------------------------------------------------------------------*/
+
+int send_bpq(unsigned char *buf, int l)
+{
+  struct ethertap_packet ethertap_packet;
+  void *addr = &ethertap_packet;
+  int offset = ETHERTAP_HEADER_LEN_MAX - ethertap_header_len;
+
+  static const unsigned char ethernet_header[18] = {
+    0x00, 0x00, 0x00, 0x02,                     /* ??? ??? ETH_P_AX25 (16bit) */ 
+    0xfe, 0xfd, 0x00, 0x00, 0x00, 0x00,         /* Destination address (kernel et
+hertap module) */
+    0xfe, 0xfe, 0x00, 0x00, 0x00, 0x00,         /* Source address (WAMPES etherta
+p module) */
+    0x08, 0xff                                  /* Protocol (bpqether) */
+  };
+
+  if (l <= 0)
+    return -1;
+
+  if (l > (sizeof(ethertap_packet.data) - 2))
+    l = sizeof(ethertap_packet.data);
+  memcpy(ethertap_packet.data + 2, buf, l);
+  memcpy(ethertap_packet.ethernet_header, (const char *) ethernet_header, sizeof(ethernet_header));
+  memcpy(ethertap_packet.ethernet_header + 4, hwaddr_remote, 6);
+  memcpy(ethertap_packet.ethernet_header + 4 + 6 + 2, hwaddr_remote +2, 6 -2);
+  ethertap_packet.data[0] = (l + 5) % 256;
+  ethertap_packet.data[1] = (l + 5) / 256;
+  l += 2;
+
+  //send_tty(addr + offset, l + sizeof(ethertap_packet.ethernet_header) - offset);
+  write(ttyfd, addr + offset, l + sizeof(ethertap_packet.ethernet_header) - offset);
+  return l;
+}
+
+/*---------------------------------------------------------------------------*/
+
+int receive_bpq(unsigned char *buf, int l)
+{
+  if ((l -= ethertap_header_len) <= 0 ||
+      buf[ethertap_header_len-2] & 0xff != 0x08 ||
+      buf[ethertap_header_len-1] & 0xff != 0xff) {
+    // not a bpqether packet.
+    // drop silently - ethernet.ax25 is not the only protocol spokenon ethernet ;)
+    return -1;
+  }
+  l -= 2;
+  if (l <= 0 && buf[ethertap_header_len] + buf[ethertap_header_len] * 256 - 5 != l) {
+    // length error in bpqether packet
+    return 0;
+  }
+
+  from_kiss(buf + ethertap_header_len + 2, l);
+  return l;
+}
+
+/*---------------------------------------------------------------------------*/
+/* TUN/TAP support for linux. ethertap is obsolete */
+
+#ifdef  TRY_TUNTAP
+static int tun_alloc(char *dev)
+{
+  struct ifreq ifr;
+  int fd, err;
+
+  if ((fd = open("/dev/net/tun", O_RDWR)) < 0)
+     return -1;
+
+  memset(&ifr, 0, sizeof(ifr));
+
+  /* Flags: IFF_TUN   - TUN device (no Ethernet headers)
+   *        IFF_TAP   - TAP device
+   *
+   *        IFF_NO_PI - Do not provide packet information
+   */
+  ifr.ifr_flags = IFF_TAP;
+  if (*dev) {
+     strncpy(ifr.ifr_name, dev, IFNAMSIZ);
+     ifr.ifr_name[IFNAMSIZ-1] = 0;
+  }
+
+  if ((err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0 ) {
+     close(fd);
+     return err;
+  }
+  strcpy(dev, ifr.ifr_name);
+
+  /* persist mode */
+  //if (ioctl(fd, TUNSETPERSIST, 1) < 0)
+    //perror("TUNSETPERSIST");
+
+  /* don't checksum */
+  //if (ioctl(fd, TUNSETNOCSUM, 1) < 0)
+    //perror("TUNSETNOCSUM");
+
+  return fd;
+}              
+#endif
+
+/*---------------------------------------------------------------------------*/
+
+int open_ethertap(char *ifname)
+{
+
+  int fd;
+  char devname[PATH_MAX];
+  struct ifreq ifr;
+  struct stat statbuf;
+  int tuntap = 0;
+  int mtu = 0;
+  int skfd;
+  
+  strcpy(devname, "/dev/");
+  strncpy(devname + 5, ifname, sizeof(devname) - 5 -1);
+  devname[sizeof(devname) -1] = 0;
+
+  // tuntap == 0: original ethertap. works on a real character device
+  if (!stat(devname, &statbuf)) {
+    fd = open(devname, O_RDWR);
+    if (fd < 0) {
+      LOGL2("%s: %s\n", devname, strerror(errno));
+      return -1;
+    }
+#ifdef  TRY_TUNTAP
+  } else {
+    strcpy(devname, ifname);
+    if ((fd = tun_alloc(devname)) < 0) {
+      LOGL2("%s: %s\n", devname, strerror(errno));
+      return -1;
+    }
+    ifname = devname;
+    tuntap = 1;
+#endif
+  }
+  ethertap_header_len = (tuntap ? ETHERTAP_HEADER_LEN_TUN : ETHERTAP_HEADER_LEN_ETHERTAP);
+
+  if ((skfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+    perror("socket()");
+    close(fd);
+    return -1;
+  }
+
+  memset(&ifr, 0, sizeof(ifr));
+
+  strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+  ifr.ifr_name[IFNAMSIZ-1] = 0;
+  if (ioctl(skfd, SIOCGIFFLAGS, &ifr) < 0)
+    perror("SIOCGIFFLAGS");
+
+  ifr.ifr_flags |= (IFF_UP | IFF_NOARP);
+  if (ioctl(skfd, SIOCSIFFLAGS, &ifr) < 0)
+    perror("SIOCSIFFLAGS");
+
+  strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+  ifr.ifr_name[IFNAMSIZ-1] = 0;
+  if (ioctl(skfd, SIOCGIFHWADDR, &ifr) < 0) {
+    perror("SIOCGIFHWADDR");
+    hwaddr_remote[0] = 0xfe;
+    hwaddr_remote[1] = 0xfd;
+    hwaddr_remote[2] = 0x0;
+    hwaddr_remote[3] = 0x0;
+    hwaddr_remote[4] = 0x0;
+    hwaddr_remote[5] = 0x0;
+  } else
+    memcpy(hwaddr_remote, ifr.ifr_hwaddr.sa_data, 6);
+
+  if (ttyspeed > ETAP_MTU_MIN && ttyspeed != 9600) {
+    mtu = ttyspeed;
+  } else {
+    strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+    ifr.ifr_name[IFNAMSIZ-1] = 0;
+    strcpy(ifr.ifr_name, ifname);
+    if (ioctl(skfd, SIOCGIFMTU, &ifr) < 0)
+      perror("SIOCGIFMTU");
+    else
+      mtu = ifr.ifr_mtu;
+  }
+  if (mtu < ETAP_MTU_MIN || mtu > ETAP_MTU_MAX)
+    mtu = ETAP_MTU;
+  strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+  ifr.ifr_name[IFNAMSIZ-1] = 0;
+  ifr.ifr_mtu = mtu;
+  if (ioctl(skfd, SIOCSIFMTU, &ifr) < 0)
+    perror("SIOSGIFMTU");
+
+  close(skfd);
+
+  return fd;
+
+}
+
+/*---------------------------------------------------------------------------*/
+
+int set_bpq_dev_call_and_up(char *ifname)
+{
+  FILE * fp;
+  char buf[1024];
+  char bpq_name[IFNAMSIZ];
+  char dev_name[IFNAMSIZ];
+  struct ifreq ifr;
+  struct sockaddr *sa;
+  int drop;
+  int skfd;
+  int len;
+  int err = -1;
+
+  // 1. find correspondent bpqether device in /proc (i.e. bpq0 for tap0)
+  // 2. set the ax25 call of bpq0 (in this example)
+  // 3. ifup bpq0
+
+  if (!(fp = fopen("/proc/net/bpqether", "r"))) {
+    perror("/proc/net/bpqether");
+    return -1;
+  }
+
+  // look up bpqether devce in /proc:
+  //   dev   ether      destination        accept from
+  //   bpq0  tap0       FF:FF:FF:FF:FF:FF  *
+
+  drop = 1;
+  *bpq_name = *dev_name = 0;
+  while (fgets(buf, sizeof(buf), fp)) {
+    if (drop) {
+      // header line
+      drop = 0;
+      continue;
+    }
+    sscanf(buf, "%s %s ", bpq_name, dev_name);
+    if (!strcmp(dev_name, ifname))
+      break;
+    *bpq_name = *dev_name = 0;
+  }
+  fclose(fp);
+  if (!*bpq_name) {
+    LOGL2("Did not found bpqether device for %s in /proc/net/bpqether: %s", ifr.ifr_name, strerror(errno));
+    return -1;
+  }
+
+  LOGL1("found bpq device %s for %s\n", bpq_name, dev_name);
+
+  if ((skfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+    perror("socket()");
+    return -1;
+  }
+  memset(&ifr, 0, sizeof(ifr));
+  memcpy(ifr.ifr_name, bpq_name, IFNAMSIZ);
+  ifr.ifr_name[IFNAMSIZ-1] = 0;
+
+  ifr.ifr_hwaddr.sa_family = PF_AX25;
+  memcpy(ifr.ifr_hwaddr.sa_data, mycallsign, 7);
+
+  if (ioctl(skfd, SIOCSIFHWADDR, &ifr) < 0) {
+    perror("SIOCSIFHWADDR");
+    close(skfd);
+    return -1;
+  }
+  strncpy(ifr.ifr_name, bpq_name, IFNAMSIZ);
+  ifr.ifr_name[IFNAMSIZ-1] = 0;
+  ifr.ifr_mtu = 256;
+  if (ioctl(skfd, SIOCSIFMTU, &ifr) < 0)
+    perror("SIOSGIFMTU");
+
+  strncpy(ifr.ifr_name, bpq_name, IFNAMSIZ);
+  ifr.ifr_name[IFNAMSIZ-1] = 0;
+  if (ioctl(skfd, SIOCGIFFLAGS, &ifr) < 0) {
+    perror("SIOCGIFFLAGS");
+    ifr.ifr_flags = 0;
+  }
+
+  ifr.ifr_flags |= (IFF_UP);
+  if (ioctl(skfd, SIOCSIFFLAGS, &ifr) < 0) {
+    perror("SIOCSIFFLAGS");
+    err = -1;
+  }
+
+  close(skfd);
+
+  return err;
+}