From e2c442cdcb84385612bc51e3f07e195a71fb3639 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Mon, 25 Jun 2018 17:42:56 -0600
Subject: [PATCH] net/procfs: Fix a design REVISIT from the integration the
 IFINDEX logic and the existing ifconfig/procfs logic.

---
 net/procfs/net_procfs.c | 32 +++++++++++++++++++-------------
 net/procfs/procfs.h     |  3 +++
 2 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/net/procfs/net_procfs.c b/net/procfs/net_procfs.c
index cb36b6f9aa..63fa2a4881 100644
--- a/net/procfs/net_procfs.c
+++ b/net/procfs/net_procfs.c
@@ -521,29 +521,35 @@ static int netprocfs_readdir(FAR struct fs_dirent_s *dir)
       else
 #endif
         {
-          int ifindex = index - DEV_INDEX;
-
-          /* Correct for the fact that the interface is not zero based */
-
-          ifindex++;
+          int ifindex;
 
 #ifdef CONFIG_NETDEV_IFINDEX
-          /* Make sure the ifindex is a valid interface index.  If not,
-           * skip to the next valid index.
-           *
-           * REVISIT:  That actual underlying indices may be sparse.  The
-           * way that level1->base.nentries is set-up assumes that
-           * the indexing is continuous and this may cause entries to be
-           * lost in the output.
+          /* For the first network device, ifindex will be zero.  We have
+           * to take some special action to get the correct starting
+           * ifindex.
            */
 
-          ifindex = netdev_nextindex(ifindex);
+          if (level1->ifindex == 0)
+            {
+              ifindex = netdev_nextindex(1);
+            }
+          else
+            {
+              ifindex = netdev_nextindex(level1->ifindex);
+            }
+
           if (ifindex < 0)
             {
               /* There are no more... one must have been unregistered */
 
               return -ENOENT;
             }
+
+          level1->ifindex = ifindex + 1;
+#else
+          /* Get the raw index, accounting for 1 based indexing */
+
+          ifindex = index - DEV_INDEX + 1;
 #endif
           /* Find the device corresponding to this device index */
 
diff --git a/net/procfs/procfs.h b/net/procfs/procfs.h
index 3b80fbbe5a..0b67a214b7 100644
--- a/net/procfs/procfs.h
+++ b/net/procfs/procfs.h
@@ -97,6 +97,9 @@ struct netprocfs_level1_s
 {
   struct procfs_dir_priv_s  base;    /* Base directory private data */
   char name[NAME_MAX + 1];           /* Name of last node visited */
+#ifdef CONFIG_NETDEV_IFINDEX
+  uint8_t ifindex;                   /* Next ifindex to visit */
+#endif
 };
 
 /* Line generating function type */