From 61e198670bd61591a29b9c6c809c957b562fb75e Mon Sep 17 00:00:00 2001
From: Chris Patterson <pattersonc@ainfosec.com>
Date: Mon, 18 May 2015 12:58:46 -0400
Subject: [PATCH] installer: fix network interface detection

There are a few issues with the NIC detection code in
network_up_for_answerfile() that will surface if:
a) you are doing a network install
b) your nics are not detected before it sets
   NIC_LIST="$(find_physical_nics)"

This problem typically occurs on multi-homed systems.

This fix cleans up the logic such that we iterate
over currently known NICs, brings the interface up,
then checks for carrier signal.  If no carrier, move on
to the next known interface.  Once all interfaces have
been checked and fail carrier check, sleep for 5 seconds
and start over (redetecting for newly available interfaces).

If carrier signal is detected, use that NIC and configure it
accordingly.

OXT-287

Signed-off-by: Chris Patterson <pattersonc@ainfosec.com>
---
 part1/stages/Get-answerfile | 92 ++++++++++++++++---------------------
 1 file changed, 40 insertions(+), 52 deletions(-)

diff --git a/part1/stages/Get-answerfile b/part1/stages/Get-answerfile
index 45a53b0..1baf8fc 100755
--- a/part1/stages/Get-answerfile
+++ b/part1/stages/Get-answerfile
@@ -43,35 +43,17 @@ nic_has_carrier()
 {
     local DEV="$1"
 
+    echo "dev=${DEV} carrier=$(cat /sys/class/net/${DEV}/carrier)" >&2
     [ "x$(cat /sys/class/net/${DEV}/carrier)" = "x1" ]
 }
 
-wait_for_carrier()
-{
-    local DEV="$1"
-    local TIMEOUT="$2"
-
-    # Give the network time to come up. Put this indication on screen even
-    # in non-interactive case:
-    dialog --infobox "\n\n     Detecting hardware..." 7 35
-
-    COUNT=0
-    while [ "${COUNT}" -lt "${TIMEOUT}" ] ; do
-        nic_has_carrier "${DEV}" && return
-        sleep 1
-        COUNT=$((COUNT + 1))
-    done
-}
-
 network_up_for_answerfile()
 {
     # 1. Is the network already up?
-    NIC_LIST="$(find_physical_nics)"
-    NIC_COUNT="$?"
-
-    for DEV in ${NIC_LIST} ; do
-        if ifconfig ${DEV} | egrep -q '^\s*UP ' ; then
+    for DEV in $(find_physical_nics); do
+        if ifconfig ${DEV} | egrep -q '^\s*UP '; then
             if ifconfig ${DEV} | egrep -q '^\s*inet addr:(12[^7]|1[^2]|[^1])' ; then
+                echo "networking already configured for dev=${DEV}" >&2
                 return 0
             fi
         fi
@@ -83,38 +65,44 @@ network_up_for_answerfile()
 
     ANSWERFILE_NW=$(read_kcmdline_opt "answerfile_nw")
     unset NIC
+    
+    # Give the network time to come up. Put this indication on screen even
+    # in non-interactive case:
+    dialog --infobox "\n\n     Detecting hardware..." 7 35
 
-    if [ -z "${ANSWERFILE_NW}" ] ; then
-        case ${NIC_COUNT} in
-            0)
-                echo "No network interfaces found: aborting.">&2
-                return 1
-                ;;
-            *)
-                # Take the first NIC with carrier.
-                for DEV in ${NIC_LIST} ; do
-                    ifconfig "${DEV}" up
-                done
-
-                wait_for_carrier $(echo ${NIC_LIST} | cut -f1 -d' ') 10
-
-                for DEV in ${NIC_LIST} ; do
-                    if nic_has_carrier "${DEV}" ; then
-                        NIC="${DEV}"
-                        break
-                    fi
-                done
-
-                for DEV in ${NIC_LIST} ; do
-                    ifconfig "${DEV}" down
-                done
-
-                if [ -z "${NIC}" ] ; then
-                    echo "No network interface with carrier: aborting.">&2
-                    return 1
+    if [ -z "${ANSWERFILE_NW}" ] ; then     
+        # Take the first NIC with carrier.
+        retries=0
+        while [ ${retries} -lt 30 ]; do
+            for DEV in $(find_physical_nics); do
+                ifconfig "${DEV}" up
+                sleep 1
+                if nic_has_carrier "${DEV}" ; then
+                    NIC="${DEV}"
+                    break
                 fi
-                ;;
-        esac
+            done
+
+            # Break if NIC has been selected
+            if [ -n "${NIC}" ]; then
+                break
+            fi
+
+            # give it a rest before retrying
+            echo "no network interface ready yet, retrying..." >&2
+            sleep 5
+            retries=$((retries + 1))
+        done
+
+        if [ -z "$(find_physical_nics)" ]; then
+            echo "No network interfaces found: aborting." >&2
+            return 1
+        fi
+        
+        if [ -z "${NIC}" ] ; then
+            echo "No network interface with carrier: aborting." >&2
+            return 1
+        fi
     else
         # TODO: change defn of this cmd line opt, to support dhcp/static config
         NIC="${ANSWERFILE_NW}"