syscall: add socket control message support for darwin, freebsd, linux

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4528113

src/pkg/syscall/Makefile

@@ -20,6 +20,7 @@ GOFILES_freebsd=\
 	bpf_bsd.go\
 	exec_unix.go\
 	route_bsd.go\
+	sockcmsg_unix.go\
 	syscall_bsd.go\
 	syscall_unix.go\
 
@@ -27,6 +28,7 @@ GOFILES_darwin=\
 	bpf_bsd.go\
 	exec_unix.go\
 	route_bsd.go\
+	sockcmsg_unix.go\
 	syscall_bsd.go\
 	syscall_unix.go\
 
@@ -34,6 +36,7 @@ GOFILES_linux=\
 	exec_unix.go\
 	lsf_linux.go\
 	netlink_linux.go\
+	sockcmsg_unix.go\
 	syscall_unix.go\
 
 GOFILES_windows=\

src/pkg/syscall/route_bsd.go

@@ -10,8 +10,6 @@ import (
 	"unsafe"
 )
 
-const darwinAMD64 = OS == "darwin" && ARCH == "amd64"
-
 // Round the length of a raw sockaddr up to align it properly.
 func rsaAlignOf(salen int) int {
 	salign := sizeofPtr

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
+}

src/pkg/syscall/syscall_bsd.go

@@ -425,6 +425,80 @@ func Sendto(fd int, p []byte, flags int, to Sockaddr) (errno int) {
 	return sendto(fd, p, flags, ptr, n)
 }
 
+//sys	recvmsg(s int, msg *Msghdr, flags int) (n int, errno int)
+
+func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, errno int) {
+	var msg Msghdr
+	var rsa RawSockaddrAny
+	msg.Name = (*byte)(unsafe.Pointer(&rsa))
+	msg.Namelen = uint32(SizeofSockaddrAny)
+	var iov Iovec
+	if len(p) > 0 {
+		iov.Base = (*byte)(unsafe.Pointer(&p[0]))
+		iov.SetLen(len(p))
+	}
+	var dummy byte
+	if len(oob) > 0 {
+		// receive at least one normal byte
+		if len(p) == 0 {
+			iov.Base = &dummy
+			iov.SetLen(1)
+		}
+		msg.Control = (*byte)(unsafe.Pointer(&oob[0]))
+		msg.SetControllen(len(oob))
+	}
+	msg.Iov = &iov
+	msg.Iovlen = 1
+	if n, errno = recvmsg(fd, &msg, flags); errno != 0 {
+		return
+	}
+	oobn = int(msg.Controllen)
+	recvflags = int(msg.Flags)
+	// source address is only specified if the socket is unconnected
+	if rsa.Addr.Family != AF_UNSPEC {
+		from, errno = anyToSockaddr(&rsa)
+	}
+	return
+}
+
+//sys	sendmsg(s int, msg *Msghdr, flags int) (errno int)
+
+func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (errno int) {
+	var ptr uintptr
+	var salen _Socklen
+	if to != nil {
+		var err int
+		ptr, salen, err = to.sockaddr()
+		if err != 0 {
+			return err
+		}
+	}
+	var msg Msghdr
+	msg.Name = (*byte)(unsafe.Pointer(ptr))
+	msg.Namelen = uint32(salen)
+	var iov Iovec
+	if len(p) > 0 {
+		iov.Base = (*byte)(unsafe.Pointer(&p[0]))
+		iov.SetLen(len(p))
+	}
+	var dummy byte
+	if len(oob) > 0 {
+		// send at least one normal byte
+		if len(p) == 0 {
+			iov.Base = &dummy
+			iov.SetLen(1)
+		}
+		msg.Control = (*byte)(unsafe.Pointer(&oob[0]))
+		msg.SetControllen(len(oob))
+	}
+	msg.Iov = &iov
+	msg.Iovlen = 1
+	if errno = sendmsg(fd, &msg, flags); errno != 0 {
+		return
+	}
+	return
+}
+
 // TODO:
 // FreeBSD has IP_SENDIF.  Darwin probably needs BSDLLCTest, see:
 // http://developer.apple.com/mac/library/samplecode/BSDLLCTest/index.html
@@ -540,14 +614,6 @@ func Futimes(fd int, tv []Timeval) (errno int) {
 
 //sys	fcntl(fd int, cmd int, arg int) (val int, errno int)
 
-func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from Sockaddr, errno int) {
-	return 0, 0, 0, nil, EAFNOSUPPORT
-}
-
-func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (errno int) {
-	return EAFNOSUPPORT
-}
-
 // TODO: wrap
 //	Acct(name nil-string) (errno int)
 //	Gethostuuid(uuid *byte, timeout *Timespec) (errno int)

src/pkg/syscall/syscall_darwin_386.go

@@ -40,4 +40,16 @@ func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Flags = uint16(flags)
 }
 
+func (iov *Iovec) SetLen(length int) {
+	iov.Len = uint32(length)
+}
+
+func (msghdr *Msghdr) SetControllen(length int) {
+	msghdr.Controllen = uint32(length)
+}
+
+func (cmsg *Cmsghdr) SetLen(length int) {
+	cmsg.Len = uint32(length)
+}
+
 func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr) // sic

src/pkg/syscall/syscall_darwin_amd64.go

@@ -39,3 +39,15 @@ func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Filter = int16(mode)
 	k.Flags = uint16(flags)
 }
+
+func (iov *Iovec) SetLen(length int) {
+	iov.Len = uint64(length)
+}
+
+func (msghdr *Msghdr) SetControllen(length int) {
+	msghdr.Controllen = uint32(length)
+}
+
+func (cmsg *Cmsghdr) SetLen(length int) {
+	cmsg.Len = uint32(length)
+}

src/pkg/syscall/syscall_freebsd_386.go

@@ -29,4 +29,16 @@ func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Flags = uint16(flags)
 }
 
+func (iov *Iovec) SetLen(length int) {
+	iov.Len = uint32(length)
+}
+
+func (msghdr *Msghdr) SetControllen(length int) {
+	msghdr.Controllen = uint32(length)
+}
+
+func (cmsg *Cmsghdr) SetLen(length int) {
+	cmsg.Len = uint32(length)
+}
+
 func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr) // sic

src/pkg/syscall/syscall_freebsd_amd64.go

@@ -28,3 +28,15 @@ func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Filter = int16(mode)
 	k.Flags = uint16(flags)
 }
+
+func (iov *Iovec) SetLen(length int) {
+	iov.Len = uint64(length)
+}
+
+func (msghdr *Msghdr) SetControllen(length int) {
+	msghdr.Controllen = uint32(length)
+}
+
+func (cmsg *Cmsghdr) SetLen(length int) {
+	cmsg.Len = uint32(length)
+}

src/pkg/syscall/syscall_linux.go

@@ -529,17 +529,17 @@ func Recvmsg(fd int, p, oob []byte, flags int) (n, oobn int, recvflags int, from
 
 func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (errno int) {
 	var ptr uintptr
-	var nsock _Socklen
+	var salen _Socklen
 	if to != nil {
 		var err int
-		ptr, nsock, err = to.sockaddr()
+		ptr, salen, err = to.sockaddr()
 		if err != 0 {
 			return err
 		}
 	}
 	var msg Msghdr
 	msg.Name = (*byte)(unsafe.Pointer(ptr))
-	msg.Namelen = uint32(nsock)
+	msg.Namelen = uint32(salen)
 	var iov Iovec
 	if len(p) > 0 {
 		iov.Base = (*byte)(unsafe.Pointer(&p[0]))

src/pkg/syscall/syscall_unix.go

@@ -16,6 +16,8 @@ var (
 	Stderr = 2
 )
 
+const darwinAMD64 = OS == "darwin" && ARCH == "amd64"
+
 func Syscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)
 func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
 func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2, err uintptr)

src/pkg/syscall/zsyscall_darwin_386.go

@@ -154,6 +154,23 @@ func sendto(s int, buf []byte, flags int, to uintptr, addrlen _Socklen) (errno i
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func recvmsg(s int, msg *Msghdr, flags int) (n int, errno int) {
+	r0, _, e1 := Syscall(SYS_RECVMSG, uintptr(s), uintptr(unsafe.Pointer(msg)), uintptr(flags))
+	n = int(r0)
+	errno = int(e1)
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func sendmsg(s int, msg *Msghdr, flags int) (errno int) {
+	_, _, e1 := Syscall(SYS_SENDMSG, uintptr(s), uintptr(unsafe.Pointer(msg)), uintptr(flags))
+	errno = int(e1)
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func kevent(kq int, change uintptr, nchange int, event uintptr, nevent int, timeout *Timespec) (n int, errno int) {
 	r0, _, e1 := Syscall6(SYS_KEVENT, uintptr(kq), uintptr(change), uintptr(nchange), uintptr(event), uintptr(nevent), uintptr(unsafe.Pointer(timeout)))
 	n = int(r0)

src/pkg/syscall/zsyscall_darwin_amd64.go

@@ -154,6 +154,23 @@ func sendto(s int, buf []byte, flags int, to uintptr, addrlen _Socklen) (errno i
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func recvmsg(s int, msg *Msghdr, flags int) (n int, errno int) {
+	r0, _, e1 := Syscall(SYS_RECVMSG, uintptr(s), uintptr(unsafe.Pointer(msg)), uintptr(flags))
+	n = int(r0)
+	errno = int(e1)
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func sendmsg(s int, msg *Msghdr, flags int) (errno int) {
+	_, _, e1 := Syscall(SYS_SENDMSG, uintptr(s), uintptr(unsafe.Pointer(msg)), uintptr(flags))
+	errno = int(e1)
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func kevent(kq int, change uintptr, nchange int, event uintptr, nevent int, timeout *Timespec) (n int, errno int) {
 	r0, _, e1 := Syscall6(SYS_KEVENT, uintptr(kq), uintptr(change), uintptr(nchange), uintptr(event), uintptr(nevent), uintptr(unsafe.Pointer(timeout)))
 	n = int(r0)

src/pkg/syscall/zsyscall_freebsd_386.go

@@ -154,6 +154,23 @@ func sendto(s int, buf []byte, flags int, to uintptr, addrlen _Socklen) (errno i
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func recvmsg(s int, msg *Msghdr, flags int) (n int, errno int) {
+	r0, _, e1 := Syscall(SYS_RECVMSG, uintptr(s), uintptr(unsafe.Pointer(msg)), uintptr(flags))
+	n = int(r0)
+	errno = int(e1)
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func sendmsg(s int, msg *Msghdr, flags int) (errno int) {
+	_, _, e1 := Syscall(SYS_SENDMSG, uintptr(s), uintptr(unsafe.Pointer(msg)), uintptr(flags))
+	errno = int(e1)
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func kevent(kq int, change uintptr, nchange int, event uintptr, nevent int, timeout *Timespec) (n int, errno int) {
 	r0, _, e1 := Syscall6(SYS_KEVENT, uintptr(kq), uintptr(change), uintptr(nchange), uintptr(event), uintptr(nevent), uintptr(unsafe.Pointer(timeout)))
 	n = int(r0)

src/pkg/syscall/zsyscall_freebsd_amd64.go

@@ -154,6 +154,23 @@ func sendto(s int, buf []byte, flags int, to uintptr, addrlen _Socklen) (errno i
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func recvmsg(s int, msg *Msghdr, flags int) (n int, errno int) {
+	r0, _, e1 := Syscall(SYS_RECVMSG, uintptr(s), uintptr(unsafe.Pointer(msg)), uintptr(flags))
+	n = int(r0)
+	errno = int(e1)
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func sendmsg(s int, msg *Msghdr, flags int) (errno int) {
+	_, _, e1 := Syscall(SYS_SENDMSG, uintptr(s), uintptr(unsafe.Pointer(msg)), uintptr(flags))
+	errno = int(e1)
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func kevent(kq int, change uintptr, nchange int, event uintptr, nevent int, timeout *Timespec) (n int, errno int) {
 	r0, _, e1 := Syscall6(SYS_KEVENT, uintptr(kq), uintptr(change), uintptr(nchange), uintptr(event), uintptr(nevent), uintptr(unsafe.Pointer(timeout)))
 	n = int(r0)