Scan subnets in parallel, update readme, update gitignore

.gitignore

@@ -2,5 +2,6 @@
 !.gitignore
 !.screenshot.png
 minipam
+MinIPAM
 *.yaml
-*.json
+*.json

README.md

@@ -11,6 +11,9 @@ there is no authorization mechanism built in.
 Scanning is kind of slow, but I prefer to keep it that way, since I don't need it to be fast, and I don't want to waste
 my compute resources. It doesn't matter for me if my scan completes within 1 minute or within 30 minutes.
 
+Subnets are scanned in parallel, but addresses in each subnet are still scanned sequentially. So complete scan takes as
+much time, as scanning of biggest subnet that you have.
+
 ![Screenshot](.screenshot.png)
 
 # Compilation
@@ -33,9 +36,13 @@ scan_subnets:
   - 192.168.145.0/24
   - 10.250.100.64.0/27
 delay_between_scans: 15m
+#Setting this to absolute path seems like a good idea :)
 persistence_location: "data.json"
+#Don't scan network and broadcast address, usually you want to leave this set to true
 exclude_special_addresses: true
 use_tls: false
+#IF use_tls is set to false, following two options are ignored.
+#key and cert and fullchain can be in one file. In this case, specify the same file in both fields
 tls_key_file: "key.pem"
 tls_cert_file: "fullchain.pem"
 ```

minipam.go

@@ -12,6 +12,7 @@ import (
 	"net/netip"
 	"os"
 	"os/exec"
+	"sync"
 	"time"
 )
 
@@ -120,77 +121,86 @@ func ping(addr string) bool {
 
 func scanner() {
 	for {
+		var wg sync.WaitGroup
+		var mutex sync.Mutex
+		for _, subnet := range conf.ScanSubnets {
 
-		for _, v := range conf.ScanSubnets {
-
-			persistenceSubnet, ok := p.Subnets[v]
-			if !ok {
-				persistenceSubnet = SubnetT{}
-				persistenceSubnet.Hosts = make(map[string]HostT)
-			}
-			log.Printf("Scanning subnet %s", v)
-			prefix, err := netip.ParsePrefix(v)
-			if err != nil {
-				log.Printf("Error: %s", err)
-				continue
-			}
-			prefix = prefix.Masked()
-			addr := prefix.Addr()
-
-			if conf.ExcludeSpecialAddresses {
-				addr = addr.Next()
-			}
-			persistenceSubnet.TotalAddresses = 0
-			persistenceSubnet.UsedAddresses = 0
-			persistenceSubnet.HostList = make([]string, 0)
-			for {
-				if !prefix.Contains(addr) {
-					break
+			go func(v string) {
+				wg.Add(1)
+				defer wg.Done()
+				persistenceSubnet, ok := p.Subnets[v]
+				if !ok {
+					persistenceSubnet = SubnetT{}
+					persistenceSubnet.Hosts = make(map[string]HostT)
 				}
-				//skip broadcast address
-				if conf.ExcludeSpecialAddresses && !prefix.Contains(addr.Next()) {
-					break
+				log.Printf("Scanning subnet %s", v)
+				prefix, err := netip.ParsePrefix(v)
+				if err != nil {
+					log.Printf("Error: %s", err)
+					return
 				}
-				persistenceSubnet.TotalAddresses++
-				//fmt.Println(addr.String())
-				persistenceSubnet.HostList = append(persistenceSubnet.HostList, addr.String())
-				pingstate := ping(addr.String())
-				host, ok := persistenceSubnet.Hosts[addr.String()]
-				if pingstate {
-					persistenceSubnet.UsedAddresses++
-					//log.Printf("%s is up", addr.String())
-					rdnsString := ""
-					rdns, err := net.LookupAddr(addr.String())
-					if err == nil {
-						if len(rdns) > 0 {
-							rdnsString = rdns[0]
-						}
+				prefix = prefix.Masked()
+				addr := prefix.Addr()
+
+				if conf.ExcludeSpecialAddresses {
+					addr = addr.Next()
+				}
+				persistenceSubnet.TotalAddresses = 0
+				persistenceSubnet.UsedAddresses = 0
+				persistenceSubnet.HostList = make([]string, 0)
+				for {
+					if !prefix.Contains(addr) {
+						break
 					}
-					if !ok {
-						persistenceSubnet.Hosts[addr.String()] = HostT{
-							FirstSeen: time.Now(),
-							LastSeen:  time.Now(),
-							Online:    true,
-							RevDNS:    rdnsString,
+					//skip broadcast address
+					if conf.ExcludeSpecialAddresses && !prefix.Contains(addr.Next()) {
+						break
+					}
+					persistenceSubnet.TotalAddresses++
+					//fmt.Println(addr.String())
+					persistenceSubnet.HostList = append(persistenceSubnet.HostList, addr.String())
+					pingstate := ping(addr.String())
+					host, ok := persistenceSubnet.Hosts[addr.String()]
+					if pingstate {
+						persistenceSubnet.UsedAddresses++
+						//log.Printf("%s is up", addr.String())
+						rdnsString := ""
+						rdns, err := net.LookupAddr(addr.String())
+						if err == nil {
+							if len(rdns) > 0 {
+								rdnsString = rdns[0]
+							}
 						}
-					} else {
-						host.LastSeen = time.Now()
-						host.Online = true
-						host.RevDNS = rdnsString
+						if !ok {
+							persistenceSubnet.Hosts[addr.String()] = HostT{
+								FirstSeen: time.Now(),
+								LastSeen:  time.Now(),
+								Online:    true,
+								RevDNS:    rdnsString,
+							}
+						} else {
+							host.LastSeen = time.Now()
+							host.Online = true
+							host.RevDNS = rdnsString
+							persistenceSubnet.Hosts[addr.String()] = host
+						}
+
+					} else if ok {
+						host.Online = false
 						persistenceSubnet.Hosts[addr.String()] = host
+						persistenceSubnet.UsedAddresses++
 					}
 
-				} else if ok {
-					host.Online = false
-					persistenceSubnet.Hosts[addr.String()] = host
-					persistenceSubnet.UsedAddresses++
+					addr = addr.Next()
 				}
-
-				addr = addr.Next()
-			}
-			p.Subnets[v] = persistenceSubnet
+				mutex.Lock()
+				p.Subnets[v] = persistenceSubnet
+				mutex.Unlock()
+				log.Printf("Scan of %s finished", v)
+			}(subnet)
 		}
-		log.Printf("Scan finished")
+		wg.Wait()
+		log.Printf("All scans finished")
 		f, err := os.Create(conf.PersistenceLocation)
 		if err != nil {
 			log.Printf("Failed to save persistence: %s", err)