From 80040c7be1da23027bcd858dc377b3ef4a834ce8 Mon Sep 17 00:00:00 2001
From: Fei Chen <feichen@meta.com>
Date: Thu, 5 Oct 2023 05:28:46 -0700
Subject: [PATCH] introduce per vip sid routing stats

Summary: as per title

Reviewed By: avasylev

Differential Revision: D49685686

fbshipit-source-id: 38636551a94aa92df70e98c83a32b60ede3772ec
---
 katran/lib/KatranLb.cpp        | 14 ++++++++++++++
 katran/lib/KatranLb.h          |  9 +++++++++
 katran/lib/bpf/balancer.bpf.c  | 25 ++++++++++++++++++++++++-
 katran/lib/bpf/balancer_maps.h |  8 ++++++++
 4 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/katran/lib/KatranLb.cpp b/katran/lib/KatranLb.cpp
index d092893ad..a47d114b1 100644
--- a/katran/lib/KatranLb.cpp
+++ b/katran/lib/KatranLb.cpp
@@ -2584,4 +2584,18 @@ std::vector<int> KatranLb::getGlobalLruMapsFds() {
   return result;
 }
 
+lb_stats KatranLb::getSidRoutingStatsForVip(const VipKey& vip) {
+  auto vip_iter = vips_.find(vip);
+  if (vip_iter == vips_.end()) {
+    LOG(INFO) << fmt::format(
+        "trying to get sid routing stats for non-existing vip  {}:{}:{}",
+        vip.address,
+        vip.port,
+        vip.proto);
+    return lb_stats{};
+  }
+  auto vipNum = vip_iter->second.getVipNum();
+  return getLbStats(vipNum, "server_id_routing_stats");
+}
+
 } // namespace katran
diff --git a/katran/lib/KatranLb.h b/katran/lib/KatranLb.h
index 866f5c1cc..c146f7a0b 100644
--- a/katran/lib/KatranLb.h
+++ b/katran/lib/KatranLb.h
@@ -812,6 +812,15 @@ class KatranLb {
    */
   lb_tpr_packets_stats getLbTprPacketsStats();
 
+  /**
+   * @param VipKey vip
+   * @return struct lb_stats w/ statistic for specified vip
+   *
+   * helper function which return total ammount of initial/sync packets and
+   * server id routed packets which has been sent to specified vip.
+   */
+  lb_stats getSidRoutingStatsForVip(const VipKey& vip);
+
  private:
   /**
    * update vipmap(add or remove vip) in forwarding plane
diff --git a/katran/lib/bpf/balancer.bpf.c b/katran/lib/bpf/balancer.bpf.c
index 08c916adc..cadb68dbd 100644
--- a/katran/lib/bpf/balancer.bpf.c
+++ b/katran/lib/bpf/balancer.bpf.c
@@ -570,6 +570,21 @@ check_and_update_real_index_in_lru(
   return DST_NOT_FOUND_IN_LRU;
 }
 
+__attribute__((__always_inline__)) static inline void
+incr_server_id_routing_stats(__u32 vip_num, bool newConn, bool misMatchInLRU) {
+  struct lb_stats* per_vip_stats =
+      bpf_map_lookup_elem(&server_id_routing_stats, &vip_num);
+  if (!per_vip_stats) {
+    return;
+  }
+  if (newConn) {
+    per_vip_stats->v1 += 1;
+  }
+  if (misMatchInLRU) {
+    per_vip_stats->v2 += 1;
+  }
+}
+
 __attribute__((__always_inline__)) static inline int
 process_packet(struct xdp_md* xdp, __u64 off, bool is_ipv6) {
   void* data = (void*)(long)xdp->data;
@@ -720,6 +735,7 @@ process_packet(struct xdp_md* xdp, __u64 off, bool is_ipv6) {
     pckt.flow.port16[0] = 0;
   }
 
+  vip_num = vip_info->vip_num;
   __u32 cpu_num = bpf_get_smp_processor_id();
   void* lru_map = bpf_map_lookup_elem(&lru_mapping, &cpu_num);
   if (!lru_map) {
@@ -794,6 +810,8 @@ process_packet(struct xdp_md* xdp, __u64 off, bool is_ipv6) {
               quic_packets_stats->dst_match_in_lru += 1;
             } else if (res == DST_MISMATCH_IN_LRU) {
               quic_packets_stats->dst_mismatch_in_lru += 1;
+              incr_server_id_routing_stats(
+                  vip_num, /* new conn */ false, /* mismatch in lru */ true);
             } else {
               /* DST_NOT_FOUND_IN_LRU */
               quic_packets_stats->dst_not_found_in_lru += 1;
@@ -809,6 +827,8 @@ process_packet(struct xdp_md* xdp, __u64 off, bool is_ipv6) {
         quic_packets_stats->ch_routed += 1;
       } else {
         quic_packets_stats->cid_initial += 1;
+        incr_server_id_routing_stats(
+            vip_num, /* new conn */ true, /* mismatch in lru */ false);
       }
     }
   }
@@ -830,6 +850,8 @@ process_packet(struct xdp_md* xdp, __u64 off, bool is_ipv6) {
 
       if (pckt.flags & F_SYN_SET) {
         tpr_packets_stats->tcp_syn += 1;
+        incr_server_id_routing_stats(
+            vip_num, /* new conn */ true, /* mismatch in lru */ false);
       } else {
         if (tcp_hdr_opt_lookup(xdp, is_ipv6, &dst, &pckt) ==
             FURTHER_PROCESSING) {
@@ -841,6 +863,8 @@ process_packet(struct xdp_md* xdp, __u64 off, bool is_ipv6) {
                 &pckt, lru_map, /* update_lru */ true);
             if (res == DST_MISMATCH_IN_LRU) {
               tpr_packets_stats->dst_mismatch_in_lru += 1;
+              incr_server_id_routing_stats(
+                  vip_num, /* new conn */ false, /* mismatch in lru */ true);
             }
           }
           tpr_packets_stats->sid_routed += 1;
@@ -905,7 +929,6 @@ process_packet(struct xdp_md* xdp, __u64 off, bool is_ipv6) {
     return XDP_DROP;
   }
 
-  vip_num = vip_info->vip_num;
   data_stats = bpf_map_lookup_elem(&stats, &vip_num);
   if (!data_stats) {
     return XDP_DROP;
diff --git a/katran/lib/bpf/balancer_maps.h b/katran/lib/bpf/balancer_maps.h
index a0bf2196d..e07ed4c7f 100644
--- a/katran/lib/bpf/balancer_maps.h
+++ b/katran/lib/bpf/balancer_maps.h
@@ -201,4 +201,12 @@ struct {
   __uint(map_flags, NO_FLAGS);
 } tpr_packets_stats_map SEC(".maps");
 
+struct {
+  __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+  __type(key, __u32);
+  __type(value, struct lb_stats);
+  __uint(max_entries, MAX_VIPS);
+  __uint(map_flags, NO_FLAGS);
+} server_id_routing_stats SEC(".maps");
+
 #endif // of _BALANCER_MAPS