X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Ftunalloc.c;fp=lib%2Ftunalloc.c;h=12c2a70e27accd15353b5b125a2f83914f0da1e4;hb=1e3f34c7693bcabae8e443ac1b246680ef9b60e2;hp=0000000000000000000000000000000000000000;hpb=079b5942276a04b2b18f1ec5bd2e07170e3ab9bd;p=sliver-openvswitch.git

diff --git a/lib/tunalloc.c b/lib/tunalloc.c
new file mode 100644
index 000000000..12c2a70e2
--- /dev/null
+++ b/lib/tunalloc.c
@@ -0,0 +1,90 @@
+/* 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 <unistd.h>
+#include <sys/socket.h>
+#include <linux/if.h>
+#include <linux/if_tun.h>
+
+#include "tunalloc.h"
+
+#define VSYS_TUNTAP "/var/run/pl-ovs.control"
+
+/* Reads vif FD from "fd", writes interface name to vif_name, and returns vif FD.
+ * vif_name should be IFNAMSIZ chars long. */
+static 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) {
+		return -1;
+	}
+	if(!rv) {
+		/* EOF */
+		return -1;
+	}
+
+	cmsg = CMSG_FIRSTHDR(&msg);
+	if (!cmsg->cmsg_type == SCM_RIGHTS) {
+		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) {
+        return -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) {
+        return -1;
+    }
+
+    remotefd = receive_vif_fd(control_fd, if_name);
+
+    close(control_fd);
+
+    return remotefd;
+}