all: sync with master; upd chlog

internal/arpdb/arpdb_bsd.go

@@ -0,0 +1,74 @@
+//go:build darwin || freebsd
+
+package arpdb
+
+import (
+	"bufio"
+	"net"
+	"net/netip"
+	"strings"
+	"sync"
+
+	"github.com/AdguardTeam/golibs/log"
+)
+
+func newARPDB() (arp *cmdARPDB) {
+	return &cmdARPDB{
+		parse: parseArpA,
+		ns: &neighs{
+			mu: &sync.RWMutex{},
+			ns: make([]Neighbor, 0),
+		},
+		cmd: "arp",
+		// Use -n flag to avoid resolving the hostnames of the neighbors.  By
+		// default ARP attempts to resolve the hostnames via DNS.  See man 8
+		// arp.
+		//
+		// See also https://github.com/AdguardTeam/AdGuardHome/issues/3157.
+		args: []string{"-a", "-n"},
+	}
+}
+
+// parseArpA parses the output of the "arp -a -n" command on macOS and FreeBSD.
+// The expected input format:
+//
+//	host.name (192.168.0.1) at ff:ff:ff:ff:ff:ff on en0 ifscope [ethernet]
+func parseArpA(sc *bufio.Scanner, lenHint int) (ns []Neighbor) {
+	ns = make([]Neighbor, 0, lenHint)
+	for sc.Scan() {
+		ln := sc.Text()
+
+		fields := strings.Fields(ln)
+		if len(fields) < 4 {
+			continue
+		}
+
+		ipStr := fields[1]
+		if len(ipStr) < 2 {
+			continue
+		}
+
+		ip, err := netip.ParseAddr(ipStr[1 : len(ipStr)-1])
+		if err != nil {
+			log.Debug("arpdb: parsing arp output: ip: %s", err)
+
+			continue
+		}
+
+		hwStr := fields[3]
+		mac, err := net.ParseMAC(hwStr)
+		if err != nil {
+			log.Debug("arpdb: parsing arp output: mac: %s", err)
+
+			continue
+		}
+
+		ns = append(ns, Neighbor{
+			IP:   ip,
+			MAC:  mac,
+			Name: validatedHostname(fields[0]),
+		})
+	}
+
+	return ns
+}