Add option to bypass Duplicate Address Detection

After several requests, here is SkipDAD to bypass Duplicate Address
Detection.

3 files changed, 18 insertions, 10 deletions

diff --git a/docs/netctl.profile.5.txt b/docs/netctl.profile.5.txt
index 74bbc6d..dfc13bb 100644
--- a/docs/netctl.profile.5.txt
+++ b/docs/netctl.profile.5.txt
@@ -180,16 +180,16 @@ network. In particular, these connection types are +ethernet+,
     Maximum time, in seconds, to wait for IPv6's Duplicate Address
     Detection to succeed. Defaults to `++3++'.
 
+'SkipDAD='::
+    Whether or not to bypass Duplicate Address Detection altogether.
+    Defaults to `++no++'.
+
 
 OPTIONS FOR `ethernet' CONNECTIONS
 ----------------------------------
 Next to the *ip options*, the following are understood for connections
 of the `ethernet' type:
 
-'SkipNoCarrier='::
-    Whether or not the absence of a carrier (plugged-in cable) is
-    acceptable. Defaults to `++no++'.
-
 'Auth8021X='::
     Set to `++yes++' to use 802.1x authentication.
 
@@ -209,6 +209,10 @@ of the `ethernet' type:
     Maximum time, in seconds, to wait for 802.1x authentication to
     succeed. Defaults to `++15++'.
 
+'SkipNoCarrier='::
+    Whether or not the absence of a carrier (plugged-in cable) is
+    acceptable. Defaults to `++no++'.
+
 
 OPTIONS FOR `wireless' CONNECTIONS
 ----------------------------------
diff --git a/src/lib/connections/ethernet b/src/lib/connections/ethernet
index 3db69a0..ce00dc3 100644
--- a/src/lib/connections/ethernet
+++ b/src/lib/connections/ethernet
@@ -19,7 +19,9 @@ ethernet_up() {
         return 1
     fi
 
-    if ! is_yes "${SkipNoCarrier:-no}"; then
+    if is_yes "${SkipNoCarrier:-no}"; then
+        SkipDAD=yes
+    else
         # Some cards are plain slow to come up. Don't fail immediately.
         if ! timeout_wait "${TimeoutCarrier:-5}" '(( $(< "/sys/class/net/$Interface/carrier") ))'; then
             report_error "No connection found on interface '$Interface' (timeout)"
diff --git a/src/lib/ip b/src/lib/ip
index a93eaee..4698595 100644
--- a/src/lib/ip
+++ b/src/lib/ip
@@ -117,7 +117,7 @@ ip_set() {
       ;;
       stateless|static)
         for addr in "${Address6[@]}"; do
-            if ! do_debug ip -6 addr add $addr dev "$Interface"; then
+            if ! do_debug ip -6 addr add $addr $(is_yes "${SkipDAD:-no}" && printf nodad) dev "$Interface"; then
                 report_error "Could not add address '$addr' to interface '$Interface'"
             fi
         done
@@ -125,10 +125,12 @@ ip_set() {
     esac
 
     if [[ $IP6 ]]; then
-        # Wait for Duplicate Address Detection to finish
-        if ! timeout_wait "${TimeoutDAD:-3}" '[[ -z "$(ip -6 addr show dev "$Interface" tentative)" ]]'; then
-            report_error "Duplicate Address Detection is taking too long on interface '$Interface'"
-            return 1
+        if ! is_yes "${SkipDAD:-no}"; then
+            # Wait for Duplicate Address Detection to finish
+            if ! timeout_wait "${TimeoutDAD:-3}" '[[ -z "$(ip -6 addr show dev "$Interface" tentative)" ]]'; then
+                report_error "Duplicate Address Detection is taking too long on interface '$Interface'"
+                return 1
+            fi
         fi
 
         # Add static IPv6 routes after DAD has finished