Some support scripts for tun/tap
Sapan Bhatia [Thu, 29 Oct 2009 00:53:18 +0000 (00:53 +0000)]
support/tun_test.c [moved from tun_test.c with 100% similarity]
support/tunalloc.c [new file with mode: 0644]
support/tunalloc.h [moved from tunalloc.h with 100% similarity]

similarity index 100%
rename from tun_test.c
rename to support/tun_test.c
diff --git a/support/tunalloc.c b/support/tunalloc.c
new file mode 100644 (file)
index 0000000..384a36d
--- /dev/null
@@ -0,0 +1,95 @@
+/* Slice-side code to allocate tuntap interface in root slice
+ * Based on bmsocket.c
+ *  Thom Haddow - 08/10/09
+ *
+ * Call tun_alloc() with IFFTUN or IFFTAP as an argument to get back fd to
+ * new tuntap interface. Interface name can be acquired via TUNGETIFF ioctl.
+ */
+
+#include <sys/un.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/socket.h>
+#include <linux/if.h>
+#include <linux/if_tun.h>
+
+#define VSYS_TUNTAP "/vsys/local_fd_tuntap.control"
+
+/* Reads vif FD from "fd", writes interface name to vif_name, and returns vif FD.
+ * vif_name should be IFNAMSIZ chars long. */
+int receive_vif_fd(int fd, char *vif_name)
+{
+       struct msghdr msg;
+       struct iovec iov;
+       int rv;
+       size_t ccmsg[CMSG_SPACE(sizeof(int)) / sizeof(size_t)];
+       struct cmsghdr *cmsg;
+
+    /* Use IOV to read interface name */
+       iov.iov_base = vif_name;
+       iov.iov_len = IFNAMSIZ;
+
+       msg.msg_name = 0;
+       msg.msg_namelen = 0;
+       msg.msg_iov = &iov;
+       msg.msg_iovlen = 1;
+       /* old BSD implementations should use msg_accrights instead of
+        * msg_control; the interface is different. */
+       msg.msg_control = ccmsg;
+       msg.msg_controllen = sizeof(ccmsg);
+
+       while(((rv = recvmsg(fd, &msg, 0)) == -1) && errno == EINTR);
+       if (rv == -1) {
+               perror("recvmsg");
+               return -1;
+       }
+       if(!rv) {
+               /* EOF */
+               return -1;
+       }
+
+       cmsg = CMSG_FIRSTHDR(&msg);
+       if (!cmsg->cmsg_type == SCM_RIGHTS) {
+               fprintf(stderr, "got control message of unknown type %d\n",
+                       cmsg->cmsg_type);
+               return -1;
+       }
+       return *(int*)CMSG_DATA(cmsg);
+}
+
+
+int tun_alloc(int iftype, char *if_name)
+{
+    int control_fd;
+    struct sockaddr_un addr;
+    int remotefd;
+
+    control_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (control_fd == -1) {
+        perror("Could not create UNIX socket\n");
+        exit(-1);
+    }
+
+    memset(&addr, 0, sizeof(struct sockaddr_un));
+    /* Clear structure */
+    addr.sun_family = AF_UNIX;
+    strncpy(addr.sun_path, VSYS_TUNTAP,
+            sizeof(addr.sun_path) - 1);
+
+    if (connect(control_fd, (struct sockaddr *) &addr,
+                sizeof(struct sockaddr_un)) == -1) {
+        perror("Could not connect to Vsys control socket");
+        exit(-1);
+    }
+
+    /* passing type param */
+    if (send(control_fd, &iftype, sizeof(iftype), 0) != sizeof(iftype)) {
+        perror("Could not send paramater to Vsys control socket");
+        exit(-1);
+    }
+
+    remotefd = receive_vif_fd(control_fd, if_name);
+    return remotefd;
+}
similarity index 100%
rename from tunalloc.h
rename to support/tunalloc.h