1 files changed, 65 insertions, 0 deletions
diff --git a/src/pkg/syscall/sockcmsg_unix.go b/src/pkg/syscall/sockcmsg_unix.go
new file mode 100644
index 000000000..f0c05eaf3
--- /dev/null
+++ b/src/pkg/syscall/sockcmsg_unix.go
@@ -0,0 +1,65 @@
+// 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.
+
+// Socket control messages
+
+package syscall
+
+import (
+	"unsafe"
+)
+
+// Round the length of a raw sockaddr up to align it propery.
+func cmsgAlignOf(salen int) int {
+	salign := sizeofPtr
+	// NOTE: It seems like 64-bit Darwin kernel still requires 32-bit
+	// aligned access to BSD subsystem.
+	if darwinAMD64 {
+		salign = 4
+	}
+	if salen == 0 {
+		return salign
+	}
+	return (salen + salign - 1) & ^(salign - 1)
+}
+
+func cmsgLen(datalen int) int {
+	return cmsgAlignOf(SizeofCmsghdr) + datalen
+}
+
+type SocketControlMessage struct {
+	Header Cmsghdr
+	Data   []byte
+}
+
+func ParseSocketControlMessage(buf []byte) ([]SocketControlMessage, int) {
+	var (
+		h     *Cmsghdr
+		dbuf  []byte
+		e     int
+		cmsgs []SocketControlMessage
+	)
+
+	for len(buf) >= cmsgLen(0) {
+		h, dbuf, e = socketControlMessageHeaderAndData(buf)
+		if e != 0 {
+			break
+		}
+		m := SocketControlMessage{}
+		m.Header = *h
+		m.Data = dbuf[:int(h.Len)-cmsgAlignOf(SizeofCmsghdr)]
+		cmsgs = append(cmsgs, m)
+		buf = buf[cmsgAlignOf(int(h.Len)):]
+	}
+
+	return cmsgs, e
+}
+
+func socketControlMessageHeaderAndData(buf []byte) (*Cmsghdr, []byte, int) {
+	h := (*Cmsghdr)(unsafe.Pointer(&buf[0]))
+	if h.Len < SizeofCmsghdr || int(h.Len) > len(buf) {
+		return nil, nil, EINVAL
+	}
+	return h, buf[cmsgAlignOf(SizeofCmsghdr):], 0
+}