Add bcnm-waitif

1 files changed, 30 insertions, 0 deletions

diff --git a/src/libbcnm/bcnm_if_getstate.c b/src/libbcnm/bcnm_if_getstate.c
new file mode 100644
index 0000000..af50268
--- /dev/null
+++ b/src/libbcnm/bcnm_if_getstate.c
@@ -0,0 +1,30 @@
+/* ISC license. */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+
+#include <bcnm/if.h>
+
+int bcnm_if_getstate (char const *ifname)
+{
+  struct ifreq blah ;
+  int sfd ;
+  int e = errno ;
+  size_t len = strlen(ifname) ;
+  if (len >= IFNAMSIZ) return (errno = ENAMETOOLONG, -1) ;
+  memcpy(blah.ifr_name, ifname, len+1) ;
+  sfd = socket(AF_INET, SOCK_DGRAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0) ;
+  if (sfd < 0) return -1 ;
+  if (ioctl(sfd, SIOCGIFFLAGS, &blah) < 0)
+    return errno == ENODEV ? (errno = e, 0) : -1 ;
+  close(sfd) ;
+  return 1 | !!(blah.ifr_flags & IFF_UP) << 1 | !!(blah.ifr_flags & IFF_RUNNING) << 2 ;
+}