unix: extend AF_CAN socket support

Fixes golang/go#40842

Change-Id: Icbb8f89e241d6990c06ee805e3dabeeb99750c8e
GitHub-Last-Rev: 360962020364460efe5128bdf07c545ba9561e94
GitHub-Pull-Request: golang/sys#78
Reviewed-on: https://go-review.googlesource.com/c/sys/+/248977
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>

unix/syscall_linux.go

@@ -1111,6 +1111,21 @@ func anyToSockaddr(fd int, rsa *RawSockaddrAny) (Sockaddr, error) {
 		}
 		return sa, nil
 
+	case AF_CAN:
+		pp := (*RawSockaddrCAN)(unsafe.Pointer(rsa))
+		sa := &SockaddrCAN{
+			Ifindex: int(pp.Ifindex),
+		}
+		rx := (*[4]byte)(unsafe.Pointer(&sa.RxID))
+		for i := 0; i < 4; i++ {
+			rx[i] = pp.Addr[i]
+		}
+		tx := (*[4]byte)(unsafe.Pointer(&sa.TxID))
+		for i := 0; i < 4; i++ {
+			tx[i] = pp.Addr[i+4]
+		}
+		return sa, nil
+
 	}
 	return nil, EAFNOSUPPORT
 }