bridge: leave TX queue length as kernel default, not 0

Not using NewLinkAttrs() or not initializing TxQLen leaves
the value as 0, which tells the kernel to set a zero-length
tx_queue_len.  That messes up FIFO traffic shapers (like pfifo)
that use the device TX queue length as the default packet
limit.  This leads to a default packet limit of 0, which drops
all packets.

diff --git a/plugins/main/bridge/bridge.go b/plugins/main/bridge/bridge.go
index 77c5215..7bbba7e 100644 (file)
--- a/plugins/main/bridge/bridge.go
+++ b/plugins/main/bridge/bridge.go
@@ -101,6 +101,11 @@ func ensureBridge(brName string, mtu int) (*netlink.Bridge, error) {
                LinkAttrs: netlink.LinkAttrs{
                        Name: brName,
                        MTU:  mtu,
+                       // Let kernel use default txqueuelen; leaving it unset
+                       // means 0, and a zero-length TX queue messes up FIFO
+                       // traffic shapers which use TX queue length as the
+                       // default packet limit
+                       TxQLen: -1,
                },
        }