SPF and DKIM checks

vendor/blitiri.com.ar/go/spf/internal/dnstest/dns.go

@@ -0,0 +1,111 @@
+// DNS resolver for testing purposes.
+//
+// In the future, when go fuzz can make use of _test.go files, we can rename
+// this file dns_test.go and remove this extra package entirely.
+// Until then, unfortunately this is the most reasonable way to share these
+// helpers between go and fuzz tests.
+package dnstest
+
+import (
+	"context"
+	"net"
+	"strings"
+)
+
+// Testing DNS resolver.
+//
+// Not exported since this is not part of the public API and only used
+// internally on tests.
+//
+type TestResolver struct {
+	Txt    map[string][]string
+	Mx     map[string][]*net.MX
+	Ip     map[string][]net.IP
+	Addr   map[string][]string
+	Cname  map[string]string
+	Errors map[string]error
+}
+
+func NewResolver() *TestResolver {
+	return &TestResolver{
+		Txt:    map[string][]string{},
+		Mx:     map[string][]*net.MX{},
+		Ip:     map[string][]net.IP{},
+		Addr:   map[string][]string{},
+		Cname:  map[string]string{},
+		Errors: map[string]error{},
+	}
+}
+
+var nxDomainErr = &net.DNSError{
+	Err:        "domain not found (for testing)",
+	IsNotFound: true,
+}
+
+func (r *TestResolver) LookupTXT(ctx context.Context, domain string) (txts []string, err error) {
+	if ctx.Err() != nil {
+		return nil, ctx.Err()
+	}
+	domain = strings.ToLower(domain)
+	domain = strings.TrimRight(domain, ".")
+	if cname, ok := r.Cname[domain]; ok {
+		return r.LookupTXT(ctx, cname)
+	}
+	if _, ok := r.Txt[domain]; !ok && r.Errors[domain] == nil {
+		return nil, nxDomainErr
+	}
+	return r.Txt[domain], r.Errors[domain]
+}
+
+func (r *TestResolver) LookupMX(ctx context.Context, domain string) (mxs []*net.MX, err error) {
+	if ctx.Err() != nil {
+		return nil, ctx.Err()
+	}
+	domain = strings.ToLower(domain)
+	domain = strings.TrimRight(domain, ".")
+	if cname, ok := r.Cname[domain]; ok {
+		return r.LookupMX(ctx, cname)
+	}
+	if _, ok := r.Mx[domain]; !ok && r.Errors[domain] == nil {
+		return nil, nxDomainErr
+	}
+	return r.Mx[domain], r.Errors[domain]
+}
+
+func (r *TestResolver) LookupIPAddr(ctx context.Context, host string) (as []net.IPAddr, err error) {
+	if ctx.Err() != nil {
+		return nil, ctx.Err()
+	}
+	host = strings.ToLower(host)
+	host = strings.TrimRight(host, ".")
+	if cname, ok := r.Cname[host]; ok {
+		return r.LookupIPAddr(ctx, cname)
+	}
+	if _, ok := r.Ip[host]; !ok && r.Errors[host] == nil {
+		return nil, nxDomainErr
+	}
+	return ipsToAddrs(r.Ip[host]), r.Errors[host]
+}
+
+func ipsToAddrs(ips []net.IP) []net.IPAddr {
+	as := []net.IPAddr{}
+	for _, ip := range ips {
+		as = append(as, net.IPAddr{IP: ip, Zone: ""})
+	}
+	return as
+}
+
+func (r *TestResolver) LookupAddr(ctx context.Context, host string) (addrs []string, err error) {
+	if ctx.Err() != nil {
+		return nil, ctx.Err()
+	}
+	host = strings.ToLower(host)
+	host = strings.TrimRight(host, ".")
+	if cname, ok := r.Cname[host]; ok {
+		return r.LookupAddr(ctx, cname)
+	}
+	if _, ok := r.Addr[host]; !ok && r.Errors[host] == nil {
+		return nil, nxDomainErr
+	}
+	return r.Addr[host], r.Errors[host]
+}