syscall: provide and use ioctlPtr for all BSD platforms

Provide ioctlPtr for all BSD platforms, then use this for BPF.
This reduces darwin specific code, as well as avoiding the use of
an indirect system call on OpenBSD.

Updates #63900

Change-Id: I81f3e74a3149150abe972f106903310e3cf26929
Reviewed-on: https://go-review.googlesource.com/c/go/+/540019
Reviewed-by: Bryan Mills <[email protected]>
Reviewed-by: Heschi Kreinick <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Run-TryBot: Joel Sing <[email protected]>
Reviewed-by: Josh Rickmar <[email protected]>

Author: 4a6f656c

src/syscall/bpf_bsd.go

@@ -1,8 +1,8 @@
-// Copyright 2011 The Go Authors. All rights reserved.
+// Copyright 2018 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.
 
-//go:build dragonfly || freebsd || netbsd || openbsd
+//go:build darwin || dragonfly || freebsd || netbsd || openbsd
 
 // Berkeley packet filter for BSD variants
 
@@ -25,55 +25,55 @@ func BpfJump(code, k, jt, jf int) *BpfInsn {
 // Deprecated: Use golang.org/x/net/bpf instead.
 func BpfBuflen(fd int) (int, error) {
 	var l int
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCGBLEN, uintptr(unsafe.Pointer(&l)))
-	if err != 0 {
-		return 0, Errno(err)
+	err := ioctlPtr(fd, BIOCGBLEN, unsafe.Pointer(&l))
+	if err != nil {
+		return 0, err
 	}
 	return l, nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func SetBpfBuflen(fd, l int) (int, error) {
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCSBLEN, uintptr(unsafe.Pointer(&l)))
-	if err != 0 {
-		return 0, Errno(err)
+	err := ioctlPtr(fd, BIOCSBLEN, unsafe.Pointer(&l))
+	if err != nil {
+		return 0, err
 	}
 	return l, nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func BpfDatalink(fd int) (int, error) {
 	var t int
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCGDLT, uintptr(unsafe.Pointer(&t)))
-	if err != 0 {
-		return 0, Errno(err)
+	err := ioctlPtr(fd, BIOCGDLT, unsafe.Pointer(&t))
+	if err != nil {
+		return 0, err
 	}
 	return t, nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func SetBpfDatalink(fd, t int) (int, error) {
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCSDLT, uintptr(unsafe.Pointer(&t)))
-	if err != 0 {
-		return 0, Errno(err)
+	err := ioctlPtr(fd, BIOCSDLT, unsafe.Pointer(&t))
+	if err != nil {
+		return 0, err
 	}
 	return t, nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func SetBpfPromisc(fd, m int) error {
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCPROMISC, uintptr(unsafe.Pointer(&m)))
-	if err != 0 {
-		return Errno(err)
+	err := ioctlPtr(fd, BIOCPROMISC, unsafe.Pointer(&m))
+	if err != nil {
+		return err
 	}
 	return nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func FlushBpf(fd int) error {
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCFLUSH, 0)
-	if err != 0 {
-		return Errno(err)
+	err := ioctlPtr(fd, BIOCFLUSH, nil)
+	if err != nil {
+		return err
 	}
 	return nil
 }
@@ -86,9 +86,9 @@ type ivalue struct {
 // Deprecated: Use golang.org/x/net/bpf instead.
 func BpfInterface(fd int, name string) (string, error) {
 	var iv ivalue
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCGETIF, uintptr(unsafe.Pointer(&iv)))
-	if err != 0 {
-		return "", Errno(err)
+	err := ioctlPtr(fd, BIOCGETIF, unsafe.Pointer(&iv))
+	if err != nil {
+		return "", err
 	}
 	return name, nil
 }
@@ -97,47 +97,47 @@ func BpfInterface(fd int, name string) (string, error) {
 func SetBpfInterface(fd int, name string) error {
 	var iv ivalue
 	copy(iv.name[:], []byte(name))
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCSETIF, uintptr(unsafe.Pointer(&iv)))
-	if err != 0 {
-		return Errno(err)
+	err := ioctlPtr(fd, BIOCSETIF, unsafe.Pointer(&iv))
+	if err != nil {
+		return err
 	}
 	return nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func BpfTimeout(fd int) (*Timeval, error) {
 	var tv Timeval
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCGRTIMEOUT, uintptr(unsafe.Pointer(&tv)))
-	if err != 0 {
-		return nil, Errno(err)
+	err := ioctlPtr(fd, BIOCGRTIMEOUT, unsafe.Pointer(&tv))
+	if err != nil {
+		return nil, err
 	}
 	return &tv, nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func SetBpfTimeout(fd int, tv *Timeval) error {
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCSRTIMEOUT, uintptr(unsafe.Pointer(tv)))
-	if err != 0 {
-		return Errno(err)
+	err := ioctlPtr(fd, BIOCSRTIMEOUT, unsafe.Pointer(tv))
+	if err != nil {
+		return err
 	}
 	return nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func BpfStats(fd int) (*BpfStat, error) {
 	var s BpfStat
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCGSTATS, uintptr(unsafe.Pointer(&s)))
-	if err != 0 {
-		return nil, Errno(err)
+	err := ioctlPtr(fd, BIOCGSTATS, unsafe.Pointer(&s))
+	if err != nil {
+		return nil, err
 	}
 	return &s, nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func SetBpfImmediate(fd, m int) error {
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCIMMEDIATE, uintptr(unsafe.Pointer(&m)))
-	if err != 0 {
-		return Errno(err)
+	err := ioctlPtr(fd, BIOCIMMEDIATE, unsafe.Pointer(&m))
+	if err != nil {
+		return err
 	}
 	return nil
 }
@@ -147,19 +147,19 @@ func SetBpf(fd int, i []BpfInsn) error {
 	var p BpfProgram
 	p.Len = uint32(len(i))
 	p.Insns = (*BpfInsn)(unsafe.Pointer(&i[0]))
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCSETF, uintptr(unsafe.Pointer(&p)))
-	if err != 0 {
-		return Errno(err)
+	err := ioctlPtr(fd, BIOCSETF, unsafe.Pointer(&p))
+	if err != nil {
+		return err
 	}
 	return nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func CheckBpfVersion(fd int) error {
 	var v BpfVersion
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCVERSION, uintptr(unsafe.Pointer(&v)))
-	if err != 0 {
-		return Errno(err)
+	err := ioctlPtr(fd, BIOCVERSION, unsafe.Pointer(&v))
+	if err != nil {
+		return err
 	}
 	if v.Major != BPF_MAJOR_VERSION || v.Minor != BPF_MINOR_VERSION {
 		return EINVAL
@@ -170,18 +170,18 @@ func CheckBpfVersion(fd int) error {
 // Deprecated: Use golang.org/x/net/bpf instead.
 func BpfHeadercmpl(fd int) (int, error) {
 	var f int
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCGHDRCMPLT, uintptr(unsafe.Pointer(&f)))
-	if err != 0 {
-		return 0, Errno(err)
+	err := ioctlPtr(fd, BIOCGHDRCMPLT, unsafe.Pointer(&f))
+	if err != nil {
+		return 0, err
 	}
 	return f, nil
 }
 
 // Deprecated: Use golang.org/x/net/bpf instead.
 func SetBpfHeadercmpl(fd, f int) error {
-	_, _, err := Syscall(SYS_IOCTL, uintptr(fd), BIOCSHDRCMPLT, uintptr(unsafe.Pointer(&f)))
-	if err != 0 {
-		return Errno(err)
+	err := ioctlPtr(fd, BIOCSHDRCMPLT, unsafe.Pointer(&f))
+	if err != nil {
+		return err
 	}
 	return nil
 }