- (djm) [Makefile.in configure.ac includes.h misc.c]

         [openbsd-compat/port-tun.c openbsd-compat/port-tun.h] Add support
         for tunnel forwarding for FreeBSD and NetBSD. NetBSD's support is
         limited to IPv4 tunnels only, and most versions don't support the
         tap(4) device at all.

1 files changed, 97 insertions, 1 deletions

diff --git a/openbsd-compat/port-tun.c b/openbsd-compat/port-tun.c
index 479b46b7a..00a0442b1 100644
--- a/openbsd-compat/port-tun.c
+++ b/openbsd-compat/port-tun.c
@@ -89,6 +89,88 @@ sys_tun_open(int tun, int mode)
 }
 #endif /* SSH_TUN_LINUX */
 
+#ifdef SSH_TUN_FREEBSD
+#include <sys/socket.h>
+#include <net/if.h>
+#include <net/if_tun.h>
+
+int
+sys_tun_open(int tun, int mode)
+{
+        struct ifreq ifr;
+        char name[100];
+        int fd = -1, sock, flag;
+        const char *tunbase = "tun";
+
+        if (mode == SSH_TUNMODE_ETHERNET) {
+#ifdef SSH_TUN_NO_L2
+                debug("%s: no layer 2 tunnelling support", __func__);
+                return (-1);
+#else
+                tunbase = "tap";
+#endif
+        }
+
+        /* Open the tunnel device */
+        if (tun <= SSH_TUNID_MAX) {
+                snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
+                fd = open(name, O_RDWR);
+        } else if (tun == SSH_TUNID_ANY) {
+                for (tun = 100; tun >= 0; tun--) {
+                        snprintf(name, sizeof(name), "/dev/%s%d",
+                            tunbase, tun);
+                        if ((fd = open(name, O_RDWR)) >= 0)
+                                break;
+                }
+        } else {
+                debug("%s: invalid tunnel %u\n", __func__, tun);
+                return (-1);
+        }
+
+        if (fd < 0) {
+                debug("%s: %s open failed: %s", __func__, name,
+                    strerror(errno));
+                return (-1);
+        }
+
+        /* Turn on tunnel headers */
+        flag = 1;
+#if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
+        if (mode != SSH_TUNMODE_ETHERNET &&
+            ioctl(fd, TUNSIFHEAD, &flag) == -1) {
+                debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
+                    strerror(errno));
+                close(fd);
+        }
+#endif
+
+        debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
+
+        /* Set the tunnel device operation mode */
+        snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
+        if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
+                goto failed;
+
+        if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
+                goto failed;
+        ifr.ifr_flags |= IFF_UP;
+        if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
+                goto failed;
+
+        close(sock);
+        return (fd);
+
+ failed:
+        if (fd >= 0)
+                close(fd);
+        if (sock >= 0)
+                close(sock);
+        debug("%s: failed to set %s mode %d: %s", __func__, name,
+            mode, strerror(errno));
+        return (-1);
+}
+#endif /* SSH_TUN_FREEBSD */
+
 /*
  * System-specific channel filters
  */
@@ -102,16 +184,29 @@ sys_tun_infilter(struct Channel *c, char *buf, int len)
 {
 #if defined(SSH_TUN_PREPEND_AF)
         char rbuf[CHAN_RBUF];
+        struct ip *iph;
 #endif
         u_int32_t *af;
         char *ptr = buf;
 
 #if defined(SSH_TUN_PREPEND_AF)
-        if (len > (int)(sizeof(rbuf) - sizeof(*af)))
+        if (len <= 0 || len > (int)(sizeof(rbuf) - sizeof(*af)))
                 return (-1);
         ptr = (char *)&rbuf[0];
         bcopy(buf, ptr + sizeof(u_int32_t), len);
         len += sizeof(u_int32_t);
+        af = (u_int32_t *)ptr;
+
+        iph = (struct ip *)(ptr + sizeof(u_int32_t));
+        switch (iph->ip_v) {
+        case 6:
+                *af = AF_INET6;
+                break;
+        case 4:
+        default:
+                *af = AF_INET;
+                break;
+        }
 #endif
 
 #if defined(SSH_TUN_COMPAT_AF)
@@ -124,6 +219,7 @@ sys_tun_infilter(struct Channel *c, char *buf, int len)
         else
                 *af = htonl(OPENBSD_AF_INET);
 #endif
+
         buffer_put_string(&c->input, ptr, len);
         return (0);
 }