1 files changed, 31 insertions, 17 deletions

diff --git a/src/pkg/net/iprawsock_posix.go b/src/pkg/net/iprawsock_posix.go
index caeeb4653..722853257 100644
--- a/src/pkg/net/iprawsock_posix.go
+++ b/src/pkg/net/iprawsock_posix.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin freebsd linux netbsd openbsd windows
+// +build darwin dragonfly freebsd linux netbsd openbsd windows
 
 package net
 
@@ -11,6 +11,18 @@ import (
 	"time"
 )
 
+// BUG(mikio): On every POSIX platform, reads from the "ip4" network
+// using the ReadFrom or ReadFromIP method might not return a complete
+// IPv4 packet, including its header, even if there is space
+// available. This can occur even in cases where Read or ReadMsgIP
+// could return a complete packet. For this reason, it is recommended
+// that you do not uses these methods if it is important to receive a
+// full packet.
+//
+// The Go 1 compatibliity guidelines make it impossible for us to
+// change the behavior of these methods; use Read or ReadMsgIP
+// instead.
+
 func sockaddrToIP(sa syscall.Sockaddr) Addr {
 	switch sa := sa.(type) {
 	case *syscall.SockaddrInet4:
@@ -39,14 +51,10 @@ func (a *IPAddr) isWildcard() bool {
 }
 
 func (a *IPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
-	return ipToSockaddr(family, a.IP, 0, a.Zone)
-}
-
-func (a *IPAddr) toAddr() sockaddr {
-	if a == nil { // nil *IPAddr
-		return nil // nil interface
+	if a == nil {
+		return nil, nil
 	}
-	return a
+	return ipToSockaddr(family, a.IP, 0, a.Zone)
 }
 
 // IPConn is the implementation of the Conn and PacketConn interfaces
@@ -125,6 +133,9 @@ func (c *IPConn) WriteToIP(b []byte, addr *IPAddr) (int, error) {
 	if !c.ok() {
 		return 0, syscall.EINVAL
 	}
+	if addr == nil {
+		return 0, &OpError{Op: "write", Net: c.fd.net, Addr: nil, Err: errMissingAddress}
+	}
 	sa, err := addr.sockaddr(c.fd.family)
 	if err != nil {
 		return 0, &OpError{"write", c.fd.net, addr, err}
@@ -151,6 +162,9 @@ func (c *IPConn) WriteMsgIP(b, oob []byte, addr *IPAddr) (n, oobn int, err error
 	if !c.ok() {
 		return 0, 0, syscall.EINVAL
 	}
+	if addr == nil {
+		return 0, 0, &OpError{Op: "write", Net: c.fd.net, Addr: nil, Err: errMissingAddress}
+	}
 	sa, err := addr.sockaddr(c.fd.family)
 	if err != nil {
 		return 0, 0, &OpError{"write", c.fd.net, addr, err}
@@ -168,19 +182,19 @@ func DialIP(netProto string, laddr, raddr *IPAddr) (*IPConn, error) {
 func dialIP(netProto string, laddr, raddr *IPAddr, deadline time.Time) (*IPConn, error) {
 	net, proto, err := parseNetwork(netProto)
 	if err != nil {
-		return nil, err
+		return nil, &OpError{Op: "dial", Net: netProto, Addr: raddr, Err: err}
 	}
 	switch net {
 	case "ip", "ip4", "ip6":
 	default:
-		return nil, UnknownNetworkError(netProto)
+		return nil, &OpError{Op: "dial", Net: netProto, Addr: raddr, Err: UnknownNetworkError(netProto)}
 	}
 	if raddr == nil {
-		return nil, &OpError{"dial", netProto, nil, errMissingAddress}
+		return nil, &OpError{Op: "dial", Net: netProto, Addr: nil, Err: errMissingAddress}
 	}
-	fd, err := internetSocket(net, laddr.toAddr(), raddr.toAddr(), deadline, syscall.SOCK_RAW, proto, "dial", sockaddrToIP)
+	fd, err := internetSocket(net, laddr, raddr, deadline, syscall.SOCK_RAW, proto, "dial", sockaddrToIP)
 	if err != nil {
-		return nil, err
+		return nil, &OpError{Op: "dial", Net: netProto, Addr: raddr, Err: err}
 	}
 	return newIPConn(fd), nil
 }
@@ -192,16 +206,16 @@ func dialIP(netProto string, laddr, raddr *IPAddr, deadline time.Time) (*IPConn,
 func ListenIP(netProto string, laddr *IPAddr) (*IPConn, error) {
 	net, proto, err := parseNetwork(netProto)
 	if err != nil {
-		return nil, err
+		return nil, &OpError{Op: "dial", Net: netProto, Addr: laddr, Err: err}
 	}
 	switch net {
 	case "ip", "ip4", "ip6":
 	default:
-		return nil, UnknownNetworkError(netProto)
+		return nil, &OpError{Op: "listen", Net: netProto, Addr: laddr, Err: UnknownNetworkError(netProto)}
 	}
-	fd, err := internetSocket(net, laddr.toAddr(), nil, noDeadline, syscall.SOCK_RAW, proto, "listen", sockaddrToIP)
+	fd, err := internetSocket(net, laddr, nil, noDeadline, syscall.SOCK_RAW, proto, "listen", sockaddrToIP)
 	if err != nil {
-		return nil, err
+		return nil, &OpError{Op: "listen", Net: netProto, Addr: laddr, Err: err}
 	}
 	return newIPConn(fd), nil
 }