1 files changed, 86 insertions, 0 deletions

diff --git a/src/lib/libc/net/if_indextoname.c b/src/lib/libc/net/if_indextoname.c
new file mode 100644
index 0000000000..f99e52e387
--- /dev/null
+++ b/src/lib/libc/net/if_indextoname.c
@@ -0,0 +1,86 @@
+/*      $OpenBSD: if_indextoname.c,v 1.9 2002/03/07 22:40:23 millert Exp $      */
+/*      $KAME: if_indextoname.c,v 1.6 2000/11/07 22:33:25 jinmei Exp $  */
+
+/*-
+ * Copyright (c) 1997, 2000
+ *      Berkeley Software Design, Inc.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *      BSDI Id: if_indextoname.c,v 2.3 2000/04/17 22:38:05 dab Exp
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <net/if_dl.h>
+#include <net/if.h>
+#include <ifaddrs.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+/*
+ * From RFC 2533:
+ *
+ * The second function maps an interface index into its corresponding
+ * name.
+ *
+ *    #include <net/if.h>
+ *
+ *    char  *if_indextoname(unsigned int ifindex, char *ifname);
+ *
+ * The ifname argument must point to a buffer of at least IF_NAMESIZE
+ * bytes into which the interface name corresponding to the specified
+ * index is returned.  (IF_NAMESIZE is also defined in <net/if.h> and
+ * its value includes a terminating null byte at the end of the
+ * interface name.) This pointer is also the return value of the
+ * function.  If there is no interface corresponding to the specified
+ * index, NULL is returned, and errno is set to ENXIO, if there was a
+ * system error (such as running out of memory), if_indextoname returns
+ * NULL and errno would be set to the proper value (e.g., ENOMEM).
+ */
+
+char *
+if_indextoname(unsigned int ifindex, char *ifname)
+{
+        struct ifaddrs *ifaddrs, *ifa;
+        int error = 0;
+
+        if (getifaddrs(&ifaddrs) < 0)
+                return(NULL);   /* getifaddrs properly set errno */
+
+        for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
+                if (ifa->ifa_addr &&
+                    ifa->ifa_addr->sa_family == AF_LINK &&
+                    ifindex == ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index)
+                        break;
+        }
+
+        if (ifa == NULL) {
+                error = ENXIO;
+                ifname = NULL;
+        }
+        else
+                strlcpy(ifname, ifa->ifa_name, IFNAMSIZ);
+
+        freeifaddrs(ifaddrs);
+
+        errno = error;
+        return(ifname);
+}