From 4b5f8537becf96d57fd7fc8e38aa6f58076163cc Mon Sep 17 00:00:00 2001
From: Simon Zolin <s.zolin@adguard.com>
Date: Mon, 1 Jun 2020 11:20:58 +0300
Subject: [PATCH] + /dhcp/reset: clear leases

---
 AGHTechDoc.md        | 11 +++++++++-
 dhcpd/dhcp_http.go   | 48 +++++++++++++++++++++++++++++++++-----------
 openapi/openapi.yaml | 10 +++++++++
 3 files changed, 56 insertions(+), 13 deletions(-)

diff --git a/AGHTechDoc.md b/AGHTechDoc.md
index 002b6232..afe6002c 100644
--- a/AGHTechDoc.md
+++ b/AGHTechDoc.md
@@ -646,16 +646,25 @@ Response:
 ### API: Reset DHCP configuration
 
 Clear all DHCP leases and configuration settings.
-DHCP server will be stopped if it's currently running.
 
 Request:
 
 	POST /control/dhcp/reset
 
+	{
+		"what": "all" | "leases"
+	}
+
 Response:
 
 	200 OK
 
+`what`:
+* all:
+	Clear all DHCP leases and configuration settings.
+	DHCP server will be stopped if it's currently running.
+* leases:
+	Clear all DHCP leases
 
 ## TLS
 
diff --git a/dhcpd/dhcp_http.go b/dhcpd/dhcp_http.go
index a6cfca26..4a98a3a1 100644
--- a/dhcpd/dhcp_http.go
+++ b/dhcpd/dhcp_http.go
@@ -415,26 +415,50 @@ func (s *Server) handleDHCPRemoveStaticLease(w http.ResponseWriter, r *http.Requ
 	}
 }
 
+type resetJSON struct {
+	What string `json:"what"`
+}
+
 func (s *Server) handleReset(w http.ResponseWriter, r *http.Request) {
-	err := s.Stop()
+	req := resetJSON{}
+	err := json.NewDecoder(r.Body).Decode(&req)
 	if err != nil {
-		log.Error("DHCP: Stop: %s", err)
+		httpError(r, w, http.StatusBadRequest, "json.Decode: %s", err)
+		return
 	}
 
+	switch req.What {
+	case "all":
+		err = s.Stop()
+		if err != nil {
+			log.Error("DHCP: Stop: %s", err)
+		}
+
+		oldconf := s.conf
+		s.conf = ServerConfig{}
+		s.conf.WorkDir = oldconf.WorkDir
+		s.conf.HTTPRegister = oldconf.HTTPRegister
+		s.conf.ConfigModified = oldconf.ConfigModified
+		s.conf.DBFilePath = oldconf.DBFilePath
+
+		s.conf.ConfigModified()
+
+	case "leases":
+		//
+
+	default:
+		httpError(r, w, http.StatusBadRequest, "unsupported 'what' value")
+		return
+	}
+
+	s.srv4.ResetLeases(nil)
+	s.srv6.ResetLeases(nil)
 	err = os.Remove(s.conf.DBFilePath)
 	if err != nil && !os.IsNotExist(err) {
 		log.Error("DHCP: os.Remove: %s: %s", s.conf.DBFilePath, err)
+	} else if err == nil {
+		log.Debug("DHCP: Deleted leases file")
 	}
-
-	oldconf := s.conf
-	s.conf = ServerConfig{}
-
-	s.conf.WorkDir = oldconf.WorkDir
-	s.conf.HTTPRegister = oldconf.HTTPRegister
-	s.conf.ConfigModified = oldconf.ConfigModified
-	s.conf.DBFilePath = oldconf.DBFilePath
-
-	s.conf.ConfigModified()
 }
 
 func (s *Server) registerHandlers() {
diff --git a/openapi/openapi.yaml b/openapi/openapi.yaml
index a47394d3..473d48d8 100644
--- a/openapi/openapi.yaml
+++ b/openapi/openapi.yaml
@@ -397,6 +397,11 @@ paths:
                 - dhcp
             operationId: dhcpReset
             summary: Reset DHCP configuration
+            requestBody:
+                content:
+                    application/json:
+                        schema:
+                            $ref: "#/components/schemas/DhcpResetRequest"
             responses:
                 "200":
                     description: OK
@@ -1366,6 +1371,11 @@ components:
                     type: string
                     description: Set if static=no
                     example: ""
+        DhcpResetRequest:
+            type: object
+            properties:
+                what:
+                    type: string
         DnsAnswer:
             type: object
             description: DNS answer section