introduce a new map to pass server id based routing flags

Summary: don't see an easy way to use the global variable in the current katran flow. introduce the map instead. The map can be removed later when the flag is enabled by default everywhere. Reviewed By: nikhildl12, avasylev Differential Revision: D49548529 fbshipit-source-id: a7c59f1fe3a3cc164adc870e6de9f75435d12fe5
facebookincubator · Oct 11, 2023 · be2795b · be2795b
1 parent bfb0f60
commit be2795b
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Showing 7 changed files with 44 additions and 2 deletions.
diff --git a/katran/lib/BalancerStructs.h b/katran/lib/BalancerStructs.h
@@ -137,4 +137,9 @@ struct lb_tpr_packets_stats {
   uint64_t tcp_syn;
 };
 
+// struct for quic routing flags
+struct lb_sid_routing_flags {
+  bool update_quic_sid_based_dst_in_lru;
+};
+
 } // namespace katran
diff --git a/katran/lib/KatranLb.cpp b/katran/lib/KatranLb.cpp
@@ -751,6 +751,7 @@ void KatranLb::loadBpfProgs() {
     if (res) {
       throw std::invalid_argument("can't load main bpf program");
     }
+    updateSvrIdRoutingFlags();
   }
 
   if (config_.enableHc) {
@@ -2598,4 +2599,16 @@ lb_stats KatranLb::getSidRoutingStatsForVip(const VipKey& vip) {
   return getLbStats(vipNum, "server_id_routing_stats");
 }
 
+void KatranLb::updateSvrIdRoutingFlags() {
+  uint32_t key = 0;
+  lb_sid_routing_flags flags;
+  flags.update_quic_sid_based_dst_in_lru = config_.updateLRUForQuic;
+  int res = bpfAdapter_->bpfUpdateMap(
+      bpfAdapter_->getMapFdByName("server_id_flags"), &key, &flags);
+  if (res) {
+    LOG(ERROR) << "can't update svr_id_routing_flags map, error: "
+               << folly::errnoStr(errno);
+  }
+}
+
 } // namespace katran
diff --git a/katran/lib/KatranLb.h b/katran/lib/KatranLb.h
@@ -821,6 +821,11 @@ class KatranLb {
    */
   lb_stats getSidRoutingStatsForVip(const VipKey& vip);
 
+  /**
+   * initialize the server id based routing flags map
+   */
+  void updateSvrIdRoutingFlags();
+
  private:
   /**
    * update vipmap(add or remove vip) in forwarding plane

diff --git a/katran/lib/KatranLbStructs.h b/katran/lib/KatranLbStructs.h
@@ -221,6 +221,7 @@ struct KatranConfig {
   bool enableCidV3 = false;
   uint32_t mainInterfaceIndex = kUnspecifiedInterfaceIndex;
   uint32_t hcInterfaceIndex = kUnspecifiedInterfaceIndex;
+  bool updateLRUForQuic = false;
 };
 
 /**

diff --git a/katran/lib/bpf/balancer.bpf.c b/katran/lib/bpf/balancer.bpf.c
@@ -804,8 +804,13 @@ process_packet(struct xdp_md* xdp, __u64 off, bool is_ipv6) {
                   xdp, data, data_end - data, false);
               return XDP_DROP;
             }
-            int res = check_and_update_real_index_in_lru(
-                &pckt, lru_map, /* update_lru */ false);
+            __u32 flags_key = 0;
+            struct lb_sid_routing_flags* flags_value =
+                bpf_map_lookup_elem(&server_id_flags, &flags_key);
+            bool update_lru =
+                flags_value && flags_value->update_quic_sid_based_dst_in_lru;
+            int res =
+                check_and_update_real_index_in_lru(&pckt, lru_map, update_lru);
             if (res == DST_MATCH_IN_LRU) {
               quic_packets_stats->dst_match_in_lru += 1;
             } else if (res == DST_MISMATCH_IN_LRU) {

diff --git a/katran/lib/bpf/balancer_maps.h b/katran/lib/bpf/balancer_maps.h
@@ -209,4 +209,12 @@ struct {
   __uint(map_flags, NO_FLAGS);
 } server_id_routing_stats SEC(".maps");
 
+struct {
+  __uint(type, BPF_MAP_TYPE_ARRAY);
+  __type(key, __u32);
+  __type(value, struct lb_sid_routing_flags);
+  __uint(max_entries, 1);
+  __uint(map_flags, NO_FLAGS);
+} server_id_flags SEC(".maps");
+
 #endif // of _BALANCER_MAPS
diff --git a/katran/lib/bpf/balancer_structs.h b/katran/lib/bpf/balancer_structs.h
@@ -163,4 +163,9 @@ struct lb_tpr_packets_stats {
   __u64 tcp_syn;
 };
 
+// struct for quic routing flags
+struct lb_sid_routing_flags {
+  bool update_quic_sid_based_dst_in_lru;
+};
+
 #endif // of _BALANCER_STRUCTS