lacp: Require non-zero system ID.

It's a bug if LACP is configured with a system ID of zero.  This
patch assert fails in this case.

2 files changed, 7 insertions, 0 deletions

diff --git a/lib/lacp.c b/lib/lacp.c
index 22cba942..6ee55c36 100644
--- a/lib/lacp.c
+++ b/lib/lacp.c
@@ -224,6 +224,8 @@ lacp_destroy(struct lacp *lacp)
 void
 lacp_configure(struct lacp *lacp, const struct lacp_settings *s)
 {
+    assert(!eth_addr_is_zero(s->id));
+
     if (!lacp->name || strcmp(s->name, lacp->name)) {
         free(lacp->name);
         lacp->name = xstrdup(s->name);
diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index 85cc79e6..f79b69cd 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -2677,6 +2677,11 @@ port_configure_lacp(struct port *port, struct lacp_settings *s)
         memcpy(s->id, port->bridge->ea, ETH_ADDR_LEN);
     }
 
+    if (eth_addr_is_zero(s->id)) {
+        VLOG_WARN("port %s: Invalid zero LACP system ID.", port->name);
+        return NULL;
+    }
+
     /* Prefer bondable links if unspecified. */
     priority = atoi(get_port_other_config(port->cfg, "lacp-system-priority",
                                           "0"));