Adding upstream version 1.22.1.upstream/1.22.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 121 insertions, 0 deletions

diff --git a/src/net/lookup_unix.go b/src/net/lookup_unix.go
new file mode 100644
index 0000000..382a2d4
--- /dev/null
+++ b/src/net/lookup_unix.go
@@ -0,0 +1,121 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build unix || js || wasip1
+
+package net
+
+import (
+	"context"
+	"internal/bytealg"
+	"sync"
+)
+
+var onceReadProtocols sync.Once
+
+// readProtocols loads contents of /etc/protocols into protocols map
+// for quick access.
+func readProtocols() {
+	file, err := open("/etc/protocols")
+	if err != nil {
+		return
+	}
+	defer file.close()
+
+	for line, ok := file.readLine(); ok; line, ok = file.readLine() {
+		// tcp    6   TCP    # transmission control protocol
+		if i := bytealg.IndexByteString(line, '#'); i >= 0 {
+			line = line[0:i]
+		}
+		f := getFields(line)
+		if len(f) < 2 {
+			continue
+		}
+		if proto, _, ok := dtoi(f[1]); ok {
+			if _, ok := protocols[f[0]]; !ok {
+				protocols[f[0]] = proto
+			}
+			for _, alias := range f[2:] {
+				if _, ok := protocols[alias]; !ok {
+					protocols[alias] = proto
+				}
+			}
+		}
+	}
+}
+
+// lookupProtocol looks up IP protocol name in /etc/protocols and
+// returns correspondent protocol number.
+func lookupProtocol(_ context.Context, name string) (int, error) {
+	onceReadProtocols.Do(readProtocols)
+	return lookupProtocolMap(name)
+}
+
+func (r *Resolver) lookupHost(ctx context.Context, host string) (addrs []string, err error) {
+	order, conf := systemConf().hostLookupOrder(r, host)
+	if order == hostLookupCgo {
+		return cgoLookupHost(ctx, host)
+	}
+	return r.goLookupHostOrder(ctx, host, order, conf)
+}
+
+func (r *Resolver) lookupIP(ctx context.Context, network, host string) (addrs []IPAddr, err error) {
+	order, conf := systemConf().hostLookupOrder(r, host)
+	if order == hostLookupCgo {
+		return cgoLookupIP(ctx, network, host)
+	}
+	ips, _, err := r.goLookupIPCNAMEOrder(ctx, network, host, order, conf)
+	return ips, err
+}
+
+func (r *Resolver) lookupPort(ctx context.Context, network, service string) (int, error) {
+	// Port lookup is not a DNS operation.
+	// Prefer the cgo resolver if possible.
+	if !systemConf().mustUseGoResolver(r) {
+		port, err := cgoLookupPort(ctx, network, service)
+		if err != nil {
+			// Issue 18213: if cgo fails, first check to see whether we
+			// have the answer baked-in to the net package.
+			if port, err := goLookupPort(network, service); err == nil {
+				return port, nil
+			}
+		}
+		return port, err
+	}
+	return goLookupPort(network, service)
+}
+
+func (r *Resolver) lookupCNAME(ctx context.Context, name string) (string, error) {
+	order, conf := systemConf().hostLookupOrder(r, name)
+	if order == hostLookupCgo {
+		if cname, err, ok := cgoLookupCNAME(ctx, name); ok {
+			return cname, err
+		}
+	}
+	return r.goLookupCNAME(ctx, name, order, conf)
+}
+
+func (r *Resolver) lookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) {
+	return r.goLookupSRV(ctx, service, proto, name)
+}
+
+func (r *Resolver) lookupMX(ctx context.Context, name string) ([]*MX, error) {
+	return r.goLookupMX(ctx, name)
+}
+
+func (r *Resolver) lookupNS(ctx context.Context, name string) ([]*NS, error) {
+	return r.goLookupNS(ctx, name)
+}
+
+func (r *Resolver) lookupTXT(ctx context.Context, name string) ([]string, error) {
+	return r.goLookupTXT(ctx, name)
+}
+
+func (r *Resolver) lookupAddr(ctx context.Context, addr string) ([]string, error) {
+	order, conf := systemConf().addrLookupOrder(r, addr)
+	if order == hostLookupCgo {
+		return cgoLookupPTR(ctx, addr)
+	}
+	return r.goLookupPTR(ctx, addr, order, conf)
+}