1 files changed, 121 insertions, 0 deletions
diff --git a/deprecated-webircgateway/pkg/dnsbl/dnsbl.go b/deprecated-webircgateway/pkg/dnsbl/dnsbl.go
new file mode 100644
index 0000000..318102e
--- /dev/null
+++ b/deprecated-webircgateway/pkg/dnsbl/dnsbl.go
@@ -0,0 +1,121 @@
+package dnsbl
+
+import (
+	"encoding/hex"
+	"fmt"
+	"net"
+	"strings"
+)
+
+type ResultList struct {
+	Listed  bool
+	Results []Result
+}
+
+/*
+Result holds the individual IP lookup results for each RBL search
+*/
+type Result struct {
+	// Blacklist is the DNSBL server that gave this result
+	Blacklist string
+	// Address is the IP address that was searched
+	Address string
+	// Listed indicates whether or not the IP was on the RBL
+	Listed bool
+	// RBL lists sometimes add extra information as a TXT record
+	// if any info is present, it will be stored here.
+	Text string
+	// Error represents any error that was encountered (DNS timeout, host not
+	// found, etc.) if any
+	Error bool
+	// ErrorType is the type of error encountered if any
+	ErrorType error
+}
+
+/*
+Convert an IP to a hostname ready for a dnsbl lookup
+127.0.0.1 becomes 1.0.0.127
+1234:1234:1234:1234:1234:1234:1234:1234 becomes 4.3.2.1.4.3.2.1.4.3.2.1.4.3.2.1.4.3.2.1.4.3.2.1.4.3.2.1.4.3.2.1
+*/
+func toDnsBlHostname(ip net.IP) string {
+	if ip.To4() != nil {
+		// IPv4
+		// Reverse the complete octects
+		splitAddress := strings.Split(ip.String(), ".")
+		for i, j := 0, len(splitAddress)-1; i < len(splitAddress)/2; i, j = i+1, j-1 {
+			splitAddress[i], splitAddress[j] = splitAddress[j], splitAddress[i]
+		}
+
+		return strings.Join(splitAddress, ".")
+	}
+
+	// IPv6
+	// Remove all : from a full expanded address, then reverse all the hex characters
+	ipv6Str := expandIPv6(ip)
+	addrHexStr := strings.ReplaceAll(ipv6Str, ":", "")
+	chars := []rune(addrHexStr)
+	for i, j := 0, len(chars)-1; i < j; i, j = i+1, j-1 {
+		chars[i], chars[j] = chars[j], chars[i]
+	}
+
+	return strings.Join(strings.Split(string(chars), ""), ".")
+}
+
+func expandIPv6(ip net.IP) string {
+	dst := make([]byte, hex.EncodedLen(len(ip)))
+	_ = hex.Encode(dst, ip)
+	return string(dst[0:4]) + ":" +
+		string(dst[4:8]) + ":" +
+		string(dst[8:12]) + ":" +
+		string(dst[12:16]) + ":" +
+		string(dst[16:20]) + ":" +
+		string(dst[20:24]) + ":" +
+		string(dst[24:28]) + ":" +
+		string(dst[28:])
+}
+
+func query(rbl string, host string, r *Result) {
+	r.Listed = false
+
+	lookup := fmt.Sprintf("%s.%s", host, rbl)
+	res, err := net.LookupHost(lookup)
+
+	if len(res) > 0 {
+		r.Listed = true
+		txt, _ := net.LookupTXT(lookup)
+		if len(txt) > 0 {
+			r.Text = txt[0]
+		}
+	}
+	if err != nil {
+		r.Error = true
+		r.ErrorType = err
+	}
+
+	return
+}
+
+func Lookup(dnsblList []string, targetHost string) (r ResultList) {
+	ip, err := net.LookupIP(targetHost)
+	if err != nil {
+		return
+	}
+
+	for _, dnsbl := range dnsblList {
+		for _, addr := range ip {
+			res := Result{}
+			res.Blacklist = dnsbl
+			res.Address = addr.String()
+
+			addr := toDnsBlHostname(addr)
+			query(dnsbl, addr, &res)
+			r.Results = append(r.Results, res)
+
+			if res.Listed {
+				r.Listed = true
+			}
+		}
+	}
+
+	return
+}