diff --git a/libc/bionic/net_if.cpp b/libc/bionic/net_if.cpp
new file mode 100644
index 0000000..a6b896e
--- /dev/null
+++ b/libc/bionic/net_if.cpp
@@ -0,0 +1,161 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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 THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS 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.
+ */
+
+#include <net/if.h>
+
+#include <errno.h>
+#include <ifaddrs.h>
+#include <linux/if_packet.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/sockios.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include "private/ErrnoRestorer.h"
+
+#include "bionic_netlink.h"
+
+char* if_indextoname(unsigned ifindex, char* ifname) {
+  int s = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+  if (s == -1) return nullptr;
+
+  struct ifreq ifr = {};
+  ifr.ifr_ifindex = ifindex;
+
+  int rc = ioctl(s, SIOCGIFNAME, &ifr);
+  ErrnoRestorer errno_restorer;
+  close(s);
+  return (rc == -1) ? nullptr : strncpy(ifname, ifr.ifr_name, IFNAMSIZ);
+}
+
+unsigned if_nametoindex(const char* ifname) {
+  int s = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+  if (s == -1) return 0;
+
+  struct ifreq ifr = {};
+  strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+  ifr.ifr_name[IFNAMSIZ - 1] = 0;
+
+  int rc = ioctl(s, SIOCGIFINDEX, &ifr);
+  ErrnoRestorer errno_restorer;
+  close(s);
+  return (rc == -1) ? 0 : ifr.ifr_ifindex;
+}
+
+struct if_list {
+  if_list* next;
+  struct if_nameindex data;
+
+  if_list(if_list** list) {
+    // push_front onto `list`.
+    next = *list;
+    *list = this;
+  }
+
+  static void Free(if_list* list, bool names_too) {
+    while (list) {
+      if_list* it = list;
+      list = it->next;
+      if (names_too) free(it->data.if_name);
+      free(it);
+    }
+  }
+};
+
+static void __if_nameindex_callback(void* context, nlmsghdr* hdr) {
+  if_list** list = reinterpret_cast<if_list**>(context);
+  if (hdr->nlmsg_type == RTM_NEWLINK) {
+    ifinfomsg* ifi = reinterpret_cast<ifinfomsg*>(NLMSG_DATA(hdr));
+
+    // Create a new entry and set the interface index.
+    if_list* new_link = new if_list(list);
+    new_link->data.if_index = ifi->ifi_index;
+
+    // Go through the various bits of information and find the name.
+    rtattr* rta = IFLA_RTA(ifi);
+    size_t rta_len = IFLA_PAYLOAD(hdr);
+    while (RTA_OK(rta, rta_len)) {
+      if (rta->rta_type == IFLA_IFNAME) {
+        new_link->data.if_name = strndup(reinterpret_cast<char*>(RTA_DATA(rta)), RTA_PAYLOAD(rta));
+      }
+      rta = RTA_NEXT(rta, rta_len);
+    }
+  }
+}
+
+struct if_nameindex* if_nameindex() {
+  if_list* list = nullptr;
+
+  // Open the netlink socket and ask for all the links;
+  NetlinkConnection nc;
+  bool okay = nc.SendRequest(RTM_GETLINK) && nc.ReadResponses(__if_nameindex_callback, &list);
+  if (!okay) {
+    if_list::Free(list, true);
+    return nullptr;
+  }
+
+  // Count the interfaces.
+  size_t interface_count = 0;
+  for (if_list* it = list; it != nullptr; it = it->next) {
+    ++interface_count;
+  }
+
+  // Build the array POSIX requires us to return.
+  struct if_nameindex* result = new struct if_nameindex[interface_count + 1];
+  if (result) {
+    struct if_nameindex* out = result;
+    for (if_list* it = list; it != nullptr; it = it->next) {
+      out->if_index = it->data.if_index;
+      out->if_name = it->data.if_name;
+      ++out;
+    }
+    out->if_index = 0;
+    out->if_name = nullptr;
+  }
+
+  // Free temporary storage.
+  if_list::Free(list, false);
+
+  return result;
+}
+
+void if_freenameindex(struct if_nameindex* array) {
+  if (array == nullptr) return;
+
+  struct if_nameindex* ptr = array;
+  while (ptr->if_index != 0 || ptr->if_name != nullptr) {
+    free(ptr->if_name);
+    ++ptr;
+  }
+
+  delete[] array;
+}