[RFC PATCH v2 3/5] tools/hotplug/Linux: Add bridge VLAN support

[Leigh Brown <leigh@xxxxxxxxxxxxx>]

Update add_to_bridge shell function to read the vlan parameter
from xenstore and set the bridge VLAN configuration for the VID.

Add additional helper functions to parse the vlan specification,
which consists of one or more of the follow:

a) single VLAN (e.g. 10).
b) contiguous range of VLANs (e.g. 10-15).
c) discontiguous range with base, increment and count
   (e.g. 100+10x9 which gives VLAN IDs 100, 110, ... 190).

A single VLAN can be suffixed with "p" to indicate the PVID, or
"u" to indicate untagged. A range of VLANs can be suffixed with
"u" to indicate untagged.  A complex example would be:

   vlan=1p/10-15/20-25u

This capability only works when using the iproute2 bridge command,
so a warning is issued if the vlan parameter is set and the bridge
command is not available, as it will be ignored.

Signed-off-by: Leigh Brown <leigh@xxxxxxxxxxxxx>
---
 tools/hotplug/Linux/xen-network-common.sh | 111 ++++++++++++++++++++++
 1 file changed, 111 insertions(+)

diff --git a/tools/hotplug/Linux/xen-network-common.sh 
b/tools/hotplug/Linux/xen-network-common.sh
index 42fa704e8d..d9fb4f7355 100644
--- a/tools/hotplug/Linux/xen-network-common.sh
+++ b/tools/hotplug/Linux/xen-network-common.sh
@@ -121,10 +121,113 @@ create_bridge () {
     fi
 }
 
+_vif_vlan_add() {
+    # References vlans, pvid and error variables from the calling function
+    local -i vid=$1
+    local flag=${2:-}
+
+    if (( vid < 1 || vid > 4094 )) ;then
+        error="vlan id $vid not between 1 and 4094"
+        return
+    fi
+    if [[ -n "${vlans[$vid]}" ]] ;then
+        error="vlan id $vid specified more than once"
+        return
+    fi
+    case $flag in
+     p) if (( pvid != 0 )) ;then
+            error="more than one pvid specified ($vid and $pvid)"
+            return
+        fi
+        pvid=$vid
+        vlans[$vid]=p ;;
+     u) vlans[$vid]=u ;;
+     *) vlans[$vid]=t ;;
+    esac
+}
+
+_vif_vlan_parse_term() {
+    # References error variable from the calling function
+    local vid incr last term=${1:-}
+
+    if [[ $term =~ ^([0-9]+)([pu])?$ ]] ;then
+        _vif_vlan_add ${BASH_REMATCH[1]} ${BASH_REMATCH[2]}
+    elif [[ $term =~ ^([0-9]+)-([0-9]+)(u)?$ ]] ;then
+        vid=${BASH_REMATCH[1]}
+        last=${BASH_REMATCH[2]}
+        if (( last >= vid )) ;then
+            for (( ; vid<=last; vid++ )) ;do
+                _vif_vlan_add $vid ${BASH_REMATCH[3]}
+            done
+        else
+           error="invalid vlan id range: $term"
+        fi
+    elif [[ $term =~ ^([0-9]+)\+([0-9]+)x([0-9]+)(u)?$ ]] ;then
+        vid=${BASH_REMATCH[1]}
+        incr=${BASH_REMATCH[2]}
+        for (( j=${BASH_REMATCH[3]}; j>0; --j, vid+=incr ))
+        do
+            _vif_vlan_add $vid ${BASH_REMATCH[4]}
+        done
+    else
+        error="invalid vlan specification: $term"
+    fi
+}
+
+_vif_vlan_validate_pvid() {
+    # References vlans and pvid variables from the calling function
+    if (( pvid == 0 )) ;then
+        if (( ${#vlans[@]} == 1 )) ;then
+            vlans[${!vlans[*]}]=p
+        else
+            error="pvid required for multiple vlan ids"
+        fi
+    fi
+}
+
+_vif_vlan_setup() {
+    # References vlans and dev variable from the calling function
+    local vid cmd
+
+    bridge vlan del dev "$dev" vid 1
+    for vid in ${!vlans[@]} ;do
+        cmd="bridge vlan add dev '$dev' vid $vid"
+        case ${vlans[$vid]} in
+             p) cmd="$cmd pvid untagged" ;;
+             u) cmd="$cmd untagged" ;;
+             t) ;;
+        esac
+        eval "$cmd"
+    done
+}
+
+_vif_vlan_membership() {
+    # The vlans, pvid, dev and error variables are used by sub-functions
+    local -A vlans=()
+    local -a terms=()
+    local -i i pvid=0
+    local dev=$1 error=""
+
+    # Split the vlan specification string into its terms
+    readarray -d / -t terms <<<$2
+    for (( i=0; i<${#terms[@]}; ++i )) ;do
+        _vif_vlan_parse_term ${terms[$i]%%[[:space:]]}
+        [[ -n "$error" ]] && break
+    done
+
+    [[ -z "$error" ]] && _vif_vlan_validate_pvid
+    [[ -z "$error" ]] && _vif_vlan_setup
+    [[ -z "$error" ]] && return 0
+
+    log error "$error"
+    return 1
+}
+
 # Usage: add_to_bridge bridge dev
 add_to_bridge () {
     local bridge=$1
     local dev=$2
+    local vlan=$(xenstore_read_default "$XENBUS_PATH/vlan" "")
 
     # Don't add $dev to $bridge if it's already on the bridge.
     if [ ! -e "/sys/class/net/${bridge}/brif/${dev}" ]; then
@@ -134,6 +237,14 @@ add_to_bridge () {
         else
             ip link set ${dev} master ${bridge}
         fi
+        if [ -n "${vlan}" ] ;then
+            if which bridge >&/dev/null; then
+                log debug "configuring VLANs for ${dev} on ${bridge}"
+                _vif_vlan_membership "${dev}" "${vlan}"
+            else
+                log warning "bridge command not available, ignoring vlan 
config"
+            fi
+        fi
     else
         log debug "$dev already on bridge $bridge"
     fi
-- 
2.39.2