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

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

14 files changed, 263 insertions, 13 deletions

diff --git a/src/pkg/syscall/Makefile b/src/pkg/syscall/Makefile
index c7f1b942c5..d7bd58373b 100644
--- a/src/pkg/syscall/Makefile
+++ b/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=\
diff --git a/src/pkg/syscall/route_bsd.go b/src/pkg/syscall/route_bsd.go
index dded97b346..7821a6d29b 100644
--- a/src/pkg/syscall/route_bsd.go
+++ b/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
diff --git a/src/pkg/syscall/sockcmsg_unix.go b/src/pkg/syscall/sockcmsg_unix.go
new file mode 100644
index 0000000000..f0c05eaf31
--- /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
+}
diff --git a/src/pkg/syscall/syscall_bsd.go b/src/pkg/syscall/syscall_bsd.go
index ec3b3167a8..2df75917b4 100644
--- a/src/pkg/syscall/syscall_bsd.go
+++ b/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)
diff --git a/src/pkg/syscall/syscall_darwin_386.go b/src/pkg/syscall/syscall_darwin_386.go
index 5101ba6c78..d76b22844b 100644
--- a/src/pkg/syscall/syscall_darwin_386.go
+++ b/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
diff --git a/src/pkg/syscall/syscall_darwin_amd64.go b/src/pkg/syscall/syscall_darwin_amd64.go
index acf7a55548..ed43723049 100644
--- a/src/pkg/syscall/syscall_darwin_amd64.go
+++ b/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)
+}
diff --git a/src/pkg/syscall/syscall_freebsd_386.go b/src/pkg/syscall/syscall_freebsd_386.go
index d0fa506c7e..d3b5a1bfec 100644
--- a/src/pkg/syscall/syscall_freebsd_386.go
+++ b/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
diff --git a/src/pkg/syscall/syscall_freebsd_amd64.go b/src/pkg/syscall/syscall_freebsd_amd64.go
index ef5aff6ef5..8c1ddf6db4 100644
--- a/src/pkg/syscall/syscall_freebsd_amd64.go
+++ b/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)
+}
diff --git a/src/pkg/syscall/syscall_linux.go b/src/pkg/syscall/syscall_linux.go
index 3b8f36da63..1d6fc76c79 100644
--- a/src/pkg/syscall/syscall_linux.go
+++ b/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]))
diff --git a/src/pkg/syscall/syscall_unix.go b/src/pkg/syscall/syscall_unix.go
index d17ef52d5c..20c8a135fe 100644
--- a/src/pkg/syscall/syscall_unix.go
+++ b/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)
diff --git a/src/pkg/syscall/zsyscall_darwin_386.go b/src/pkg/syscall/zsyscall_darwin_386.go
index bbaceee196..436953ecaa 100644
--- a/src/pkg/syscall/zsyscall_darwin_386.go
+++ b/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)
diff --git a/src/pkg/syscall/zsyscall_darwin_amd64.go b/src/pkg/syscall/zsyscall_darwin_amd64.go
index ee39eadc11..1ba4c3cfe5 100644
--- a/src/pkg/syscall/zsyscall_darwin_amd64.go
+++ b/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)
diff --git a/src/pkg/syscall/zsyscall_freebsd_386.go b/src/pkg/syscall/zsyscall_freebsd_386.go
index 4f7fdefba1..d152e43806 100644
--- a/src/pkg/syscall/zsyscall_freebsd_386.go
+++ b/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)
diff --git a/src/pkg/syscall/zsyscall_freebsd_amd64.go b/src/pkg/syscall/zsyscall_freebsd_amd64.go
index 609ecdd2a9..156b087e39 100644
--- a/src/pkg/syscall/zsyscall_freebsd_amd64.go
+++ b/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)