Build PCAP file with atomic blocking writes

The previous use of non-blocking writes could result in corrupt PCAP files if a
partial write occurs. Using (*os.File).Write solves this problem by not
allowing partial writes. This change does not increase allocations (in one path
it actually reduces them), but does add additional copying.

PiperOrigin-RevId: 209652974
Change-Id: I4b1cf2eda4cfd7f237a4245aceb7391b3055a66c

1 files changed, 0 insertions, 23 deletions

diff --git a/pkg/tcpip/link/rawfile/rawfile_unsafe.go b/pkg/tcpip/link/rawfile/rawfile_unsafe.go
index 261d350d7..cea3cd6a1 100644
--- a/pkg/tcpip/link/rawfile/rawfile_unsafe.go
+++ b/pkg/tcpip/link/rawfile/rawfile_unsafe.go
@@ -94,29 +94,6 @@ func NonBlockingWrite2(fd int, b1, b2 []byte) *tcpip.Error {
 	return nil
 }
 
-// NonBlockingWriteN writes up to N byte slices to a file descriptor in a
-// single syscall. It fails if partial data is written.
-func NonBlockingWriteN(fd int, bs ...[]byte) *tcpip.Error {
-	iovec := make([]syscall.Iovec, 0, len(bs))
-
-	for _, b := range bs {
-		if len(b) == 0 {
-			continue
-		}
-		iovec = append(iovec, syscall.Iovec{
-			Base: &b[0],
-			Len:  uint64(len(b)),
-		})
-	}
-
-	_, _, e := syscall.RawSyscall(syscall.SYS_WRITEV, uintptr(fd), uintptr(unsafe.Pointer(&iovec[0])), uintptr(len(iovec)))
-	if e != 0 {
-		return TranslateErrno(e)
-	}
-
-	return nil
-}
-
 type pollEvent struct {
 	fd      int32
 	events  int16