v0.22.0 several enhancements and fixes for security, network, doc, test, packaging

internal/core/const_test.go

@@ -0,0 +1,53 @@
+package core
+
+import (
+	"net"
+	"testing"
+
+	"logwisp/internal/testutil"
+)
+
+// The host literal picks the family, strictly: an IPv4 literal or the empty
+// host is IPv4 only, an IPv6 literal (the wildcard :: too) IPv6 only, and a
+// hostname resolves. Brackets and ports belong to addresses, not hosts, and
+// an IPv4-mapped address is IPv4 written as IPv6.
+func TestNetworkFollowsTheHostLiteral(t *testing.T) {
+	for _, tc := range []struct{ host, want string }{
+		{"127.0.0.1", "tcp4"}, {"0.0.0.0", "tcp4"}, {"", "tcp4"},
+		{"::1", "tcp6"}, {"::", "tcp6"}, {"fe80::1%eth0", "tcp6"},
+		{"relay.example", "tcp"}, {"localhost", "tcp"},
+		{"[::1]", ""}, {"::1]", ""}, {"10.0.0.1:80", ""}, {"::ffff:10.0.0.1", ""},
+	} {
+		got, err := Network(tc.host)
+		if got != tc.want || (err != nil) != (tc.want == "") {
+			t.Errorf("Network(%q) = %q, %v; want %q", tc.host, got, err, tc.want)
+		}
+	}
+
+	testutil.RequireIPv6(t)
+	network, _ := Network("::")
+	ln, err := net.Listen(network, "[::]:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { ln.Close() })
+	go func() {
+		for {
+			c, err := ln.Accept()
+			if err != nil {
+				return
+			}
+			c.Close()
+		}
+	}()
+	_, port, _ := net.SplitHostPort(ln.Addr().String())
+	if c, err := net.Dial("tcp4", net.JoinHostPort("127.0.0.1", port)); err == nil {
+		c.Close()
+		t.Error(":: accepted an IPv4 connection")
+	}
+	c, err := net.Dial("tcp6", net.JoinHostPort("::1", port))
+	if err != nil {
+		t.Fatalf(":: refused [::1]: %v", err)
+	}
+	c.Close()
+}