1 /* Slice-side code to allocate tuntap interface in root slice
3 * Thom Haddow - 08/10/09
5 * Call tun_alloc() with IFFTUN or IFFTAP as an argument to get back fd to
6 * new tuntap interface. Interface name can be acquired via TUNGETIFF ioctl.
15 #include <sys/socket.h>
17 #include <linux/if_tun.h>
21 #define VSYS_TUNTAP "/var/run/pl-ovs.control"
23 /* Reads vif FD from "fd", writes interface name to vif_name, and returns vif FD.
24 * vif_name should be IFNAMSIZ chars long. */
25 static int receive_vif_fd(int fd, char *vif_name)
30 size_t ccmsg[CMSG_SPACE(sizeof(int)) / sizeof(size_t)];
33 /* Use IOV to read interface name */
34 iov.iov_base = vif_name;
35 iov.iov_len = IFNAMSIZ;
41 /* old BSD implementations should use msg_accrights instead of
42 * msg_control; the interface is different. */
43 msg.msg_control = ccmsg;
44 msg.msg_controllen = sizeof(ccmsg);
46 while(((rv = recvmsg(fd, &msg, 0)) == -1) && errno == EINTR);
55 cmsg = CMSG_FIRSTHDR(&msg);
56 if (!cmsg->cmsg_type == SCM_RIGHTS) {
59 return *(int*)CMSG_DATA(cmsg);
63 int tun_alloc(int iftype, char *if_name)
66 struct sockaddr_un addr;
69 control_fd = socket(AF_UNIX, SOCK_STREAM, 0);
70 if (control_fd == -1) {
74 memset(&addr, 0, sizeof(struct sockaddr_un));
76 addr.sun_family = AF_UNIX;
77 strncpy(addr.sun_path, VSYS_TUNTAP,
78 sizeof(addr.sun_path) - 1);
80 if (connect(control_fd, (struct sockaddr *) &addr,
81 sizeof(struct sockaddr_un)) == -1) {
85 remotefd = receive_vif_fd(control_fd, if_name);