From 3c217d82f710843f1f19b8234a3a9fc5b43ac23d Mon Sep 17 00:00:00 2001
From: Francis Dupont <fdupont@isc.org>
Date: Tue, 12 Mar 2024 16:24:10 +0100
Subject: [PATCH] [#3262] Optimized getSubnet() (#3268 1st point)

---
 src/lib/dhcpsrv/cfg_subnets4.cc | 20 ++++----------------
 src/lib/dhcpsrv/cfg_subnets4.h  |  8 ++++----
 src/lib/dhcpsrv/cfg_subnets6.cc | 20 ++++----------------
 src/lib/dhcpsrv/cfg_subnets6.h  |  8 ++++----
 4 files changed, 16 insertions(+), 40 deletions(-)

diff --git a/src/lib/dhcpsrv/cfg_subnets4.cc b/src/lib/dhcpsrv/cfg_subnets4.cc
index 5b91f3c916..681f4c36f0 100644
--- a/src/lib/dhcpsrv/cfg_subnets4.cc
+++ b/src/lib/dhcpsrv/cfg_subnets4.cc
@@ -183,13 +183,6 @@ CfgSubnets4::merge(CfgOptionDefPtr cfg_def, CfgSharedNetworks4Ptr networks,
     }
 }
 
-ConstSubnet4Ptr
-CfgSubnets4::getBySubnetId(const SubnetID& subnet_id) const {
-    auto const& index = subnets_.get<SubnetSubnetIdIndexTag>();
-    auto subnet_it = index.find(subnet_id);
-    return ((subnet_it != index.cend()) ? (*subnet_it) : ConstSubnet4Ptr());
-}
-
 ConstSubnet4Ptr
 CfgSubnets4::getByPrefix(const std::string& subnet_text) const {
     auto const& index = subnets_.get<SubnetPrefixIndexTag>();
@@ -459,15 +452,10 @@ CfgSubnets4::selectSubnet(const std::string& iface,
 }
 
 Subnet4Ptr
-CfgSubnets4::getSubnet(const SubnetID id) const {
-    /// @todo: Once this code is migrated to multi-index container, use
-    /// an index rather than full scan.
-    for (auto const& subnet : subnets_) {
-        if (subnet->getID() == id) {
-            return (subnet);
-        }
-    }
-    return (Subnet4Ptr());
+CfgSubnets4::getSubnet(const SubnetID subnet_id) const {
+    auto const& index = subnets_.get<SubnetSubnetIdIndexTag>();
+    auto subnet_it = index.find(subnet_id);
+    return ((subnet_it != index.cend()) ? (*subnet_it) : Subnet4Ptr());
 }
 
 Subnet4Ptr
diff --git a/src/lib/dhcpsrv/cfg_subnets4.h b/src/lib/dhcpsrv/cfg_subnets4.h
index 57b7e00e68..5d2519b9e6 100644
--- a/src/lib/dhcpsrv/cfg_subnets4.h
+++ b/src/lib/dhcpsrv/cfg_subnets4.h
@@ -135,7 +135,9 @@ public:
     ///
     /// @return Pointer to the @c Subnet4 object or null pointer if such
     /// subnet doesn't exist.
-    ConstSubnet4Ptr getBySubnetId(const SubnetID& subnet_id) const;
+    ConstSubnet4Ptr getBySubnetId(const SubnetID& subnet_id) const {
+        return (getSubnet(subnet_id));
+    }
 
     /// @brief Returns const pointer to a subnet which matches the specified
     /// prefix in the canonical form.
@@ -221,11 +223,9 @@ public:
 
     /// @brief Returns subnet with specified subnet-id value
     ///
-    /// Warning: this method uses full scan. Its use is not recommended for
-    /// packet processing.
     /// Please use @ref getBySubnetId instead when possible.
     ///
-    /// @return Subnet (or NULL)
+    /// @return Subnet (or null)
     Subnet4Ptr getSubnet(const SubnetID id) const;
 
     /// @brief Returns a pointer to a subnet if provided address is in its range.
diff --git a/src/lib/dhcpsrv/cfg_subnets6.cc b/src/lib/dhcpsrv/cfg_subnets6.cc
index 0b77ef43f4..704cd42cb9 100644
--- a/src/lib/dhcpsrv/cfg_subnets6.cc
+++ b/src/lib/dhcpsrv/cfg_subnets6.cc
@@ -185,13 +185,6 @@ CfgSubnets6::merge(CfgOptionDefPtr cfg_def, CfgSharedNetworks6Ptr networks,
     }
 }
 
-ConstSubnet6Ptr
-CfgSubnets6::getBySubnetId(const SubnetID& subnet_id) const {
-    auto const& index = subnets_.get<SubnetSubnetIdIndexTag>();
-    auto subnet_it = index.find(subnet_id);
-    return ((subnet_it != index.cend()) ? (*subnet_it) : ConstSubnet6Ptr());
-}
-
 ConstSubnet6Ptr
 CfgSubnets6::getByPrefix(const std::string& subnet_text) const {
     auto const& index = subnets_.get<SubnetPrefixIndexTag>();
@@ -375,15 +368,10 @@ CfgSubnets6::selectSubnet(const OptionPtr& interface_id,
 }
 
 Subnet6Ptr
-CfgSubnets6::getSubnet(const SubnetID id) const {
-    /// @todo: Once this code is migrated to multi-index container, use
-    /// an index rather than full scan.
-    for (auto const& subnet : subnets_) {
-        if (subnet->getID() == id) {
-            return (subnet);
-        }
-    }
-    return (Subnet6Ptr());
+CfgSubnets6::getSubnet(const SubnetID subnet_id) const {
+    auto const& index = subnets_.get<SubnetSubnetIdIndexTag>();
+    auto subnet_it = index.find(subnet_id);
+    return ((subnet_it != index.cend()) ? (*subnet_it) : Subnet6Ptr());
 }
 
 SubnetIDSet
diff --git a/src/lib/dhcpsrv/cfg_subnets6.h b/src/lib/dhcpsrv/cfg_subnets6.h
index ddf17d6499..9e618b4422 100644
--- a/src/lib/dhcpsrv/cfg_subnets6.h
+++ b/src/lib/dhcpsrv/cfg_subnets6.h
@@ -136,7 +136,9 @@ public:
     ///
     /// @return Pointer to the @c Subnet6 object or null pointer if such
     /// subnet doesn't exist.
-    ConstSubnet6Ptr getBySubnetId(const SubnetID& subnet_id) const;
+    ConstSubnet6Ptr getBySubnetId(const SubnetID& subnet_id) const {
+        return (getSubnet(subnet_id));
+    }
 
     /// @brief Returns const pointer to a subnet which matches the specified
     /// prefix in the canonical form.
@@ -203,11 +205,9 @@ public:
 
     /// @brief Returns subnet with specified subnet-id value
     ///
-    /// Warning: this method uses full scan. Its use is not recommended for
-    /// packet processing.
     /// Please use @ref getBySubnetId instead when possible.
     ///
-    /// @return Subnet (or NULL)
+    /// @return Subnet (or null)
     Subnet6Ptr getSubnet(const SubnetID id) const;
 
     /// @brief Selects the subnet using a specified address.
-- 
2.47.3