[#2022] Checkpoint: last version of parking code

src/bin/dhcp6/dhcp6_srv.cc

@@ -1004,6 +1004,23 @@ Dhcpv6Srv::processLocalizedQuery6AndSendResponse(Pkt6Ptr query,
  }
 }
 
+void
+Dhcpv6Srv::processLocalizedQuery6AndSendResponse(Pkt6Ptr query) {
+ // Initialize context.
+ AllocEngine::ClientContext6 ctx;
+ initContext0(query, ctx);
+
+ // Subnet is cached in the callout context associated to the query.
+ try {
+ CalloutHandlePtr callout_handle = getCalloutHandle(query);
+ callout_handle->getContext("subnet6", ctx.subnet_);
+ } catch (const Exception&) {
+ // No subnet, leave it to null...
+ }
+
+ processLocalizedQuery6AndSendResponse(query, ctx);
+}
+
 Pkt6Ptr
 Dhcpv6Srv::processLocalizedQuery6(AllocEngine::ClientContext6& ctx) {
  Pkt6Ptr query = ctx.query_;
@@ -1991,8 +2008,32 @@ Dhcpv6Srv::selectSubnet(const Pkt6Ptr& question, bool& drop) {
  CfgMgr::instance().getCurrentCfg()->
  getCfgSubnets6()->getAll());
 
+ // We proactively park the packet.
+ HooksManager::park("subnet6_select", question,
+ [this, question] () {
+ processLocalizedQuery6AndSendResponse(question);
+ });
+
  // Call user (and server-side) callouts
- HooksManager::callCallouts(Hooks.hook_index_subnet6_select_, *callout_handle);
+ try {
+ HooksManager::callCallouts(Hooks.hook_index_subnet6_select_,
+ *callout_handle);
+ } catch (...) {
+ // Make sure we don't orphan a parked packet.
+ HooksManager::drop("subnet6_select", question);
+ throw;
+ }
+
+ // Callouts parked the packet. Same as drop but callouts will resume
+ // processing or drop the packet later.
+ if (callout_handle->getStatus() == CalloutHandle::NEXT_STEP_PARK) {
+ LOG_DEBUG(hooks_logger, DBG_DHCP6_HOOKS, DHCP6_HOOK_SUBNET6_SELECT_PARK)
+ .arg(question->getLabel());
+ drop = true;
+ return (Subnet6Ptr());
+ } else {
+ HooksManager::drop("subnet6_select", question);
+ }
 
  // Callouts decided to skip this step. This means that no
  // subnet will be selected. Packet processing will continue,
@@ -2013,15 +2054,6 @@ Dhcpv6Srv::selectSubnet(const Pkt6Ptr& question, bool& drop) {
  return (Subnet6Ptr());
  }
 
- // Callouts parked the packet. Same as drop but callouts will resume
- // processing or drop the packet later.
- if (callout_handle->getStatus() == CalloutHandle::NEXT_STEP_PARK) {
- LOG_DEBUG(hooks_logger, DBG_DHCP6_HOOKS, DHCP6_HOOK_SUBNET6_SELECT_PARK)
- .arg(question->getLabel());
- drop = true;
- return (Subnet6Ptr());
- }
-
  // Use whatever subnet was specified by the callout
  callout_handle->getArgument("subnet6", subnet);
  }

src/bin/dhcp6/dhcp6_srv.h

@@ -217,6 +217,14 @@ class Dhcpv6Srv : public process::Daemon {
  void processLocalizedQuery6AndSendResponse(Pkt6Ptr query,
  AllocEngine::ClientContext6& ctx);
 
+ /// @brief Process a localized incoming DHCPv6 query.
+ ///
+ /// A variant of the precedent method used to resume processing
+ /// for packets parked in the subnet6_select callout.
+ ///
+ /// @param query A pointer to the unparked packet.
+ void processLocalizedQuery6AndSendResponse(Pkt6Ptr query);
+
  /// @brief Instructs the server to shut down.
  void shutdown() override;