Data Structures | |
| struct | s_PXENV_TFTP_READ_FILE |
| Parameter block for pxenv_tftp_read_file(). More... | |
Defines | |
| #define | PXENV_TFTP_READ_FILE 0x0023 |
| PXE API function code for pxenv_tftp_read_file(). | |
Typedefs | |
| typedef struct s_PXENV_TFTP_READ_FILE | PXENV_TFTP_READ_FILE_t |
Functions | |
| PXENV_EXIT_t | pxenv_tftp_read_file (struct s_PXENV_TFTP_READ_FILE *tftp_read_file) |
| TFTP/MTFTP read file. | |
| #define PXENV_TFTP_READ_FILE 0x0023 |
PXE API function code for pxenv_tftp_read_file().
Definition at line 660 of file pxe_api.h.
Referenced by pxe_api_call().
| typedef struct s_PXENV_TFTP_READ_FILE PXENV_TFTP_READ_FILE_t |
| PXENV_EXIT_t pxenv_tftp_read_file | ( | struct s_PXENV_TFTP_READ_FILE * | tftp_read_file | ) |
TFTP/MTFTP read file.
| tftp_read_file | Pointer to a struct s_PXENV_TFTP_READ_FILE | |
| s_PXENV_TFTP_READ_FILE::FileName | File name | |
| s_PXENV_TFTP_READ_FILE::BufferSize | Size of the receive buffer | |
| s_PXENV_TFTP_READ_FILE::Buffer | Address of the receive buffer | |
| s_PXENV_TFTP_READ_FILE::ServerIPAddress | TFTP server IP address | |
| s_PXENV_TFTP_READ_FILE::GatewayIPAddress | Relay agent IP address | |
| s_PXENV_TFTP_READ_FILE::McastIPAddress | File's multicast IP address | |
| s_PXENV_TFTP_READ_FILE::TFTPClntPort | Client multicast UDP port | |
| s_PXENV_TFTP_READ_FILE::TFTPSrvPort | Server multicast UDP port | |
| s_PXENV_TFTP_READ_FILE::TFTPOpenTimeOut | Time to wait for first packet | |
| s_PXENV_TFTP_READ_FILE::TFTPReopenDelay | MTFTP inactivity timeout |
| PXENV_EXIT_SUCCESS | File downloaded successfully | |
| PXENV_EXIT_FAILURE | File not downloaded | |
| s_PXENV_TFTP_READ_FILE::Status | PXE status code | |
| s_PXENV_TFTP_READ_FILE::BufferSize | Length of downloaded file |
The PXE specification does not make it clear how the caller requests that MTFTP be used rather than TFTP (or vice versa). One reasonable guess is that setting s_PXENV_TFTP_READ_FILE::McastIPAddress to 0.0.0.0 would cause TFTP to be used instead of MTFTP, though it is conceivable that some PXE stacks would interpret that as "use the DHCP-provided multicast IP address" instead. Some PXE stacks will not implement MTFTP at all, and will always use TFTP.
It is not specified whether or not s_PXENV_TFTP_READ_FILE::TFTPSrvPort will be used as the TFTP server port for TFTP (rather than MTFTP) downloads. Callers should assume that the only way to access a TFTP server on a non-standard port is to use pxenv_tftp_open() and pxenv_tftp_read().
If s_PXENV_TFTP_READ_FILE::GatewayIPAddress is 0.0.0.0, normal IP routing will take place. See the relevant implementation note for more details.
It is interesting to note that s_PXENV_TFTP_READ_FILE::Buffer is an ADDR32_t type, i.e. nominally a flat physical address. Some PXE NBPs (e.g. NTLDR) are known to call pxenv_tftp_read_file() in real mode with s_PXENV_TFTP_READ_FILE::Buffer set to an address above 1MB. This means that PXE stacks must be prepared to write to areas outside base memory. Exactly how this is to be achieved is not specified, though using INT 15,87 is as close to a standard method as any, and should probably be used. Switching to protected-mode in order to access high memory will fail if pxenv_tftp_read_file() is called in V86 mode; it is reasonably to expect that a V86 monitor would intercept the relatively well-defined INT 15,87 if it wants the PXE stack to be able to write to high memory.
Things get even more interesting if pxenv_tftp_read_file() is called in protected mode, because there is then absolutely no way for the PXE stack to write to an absolute physical address. You can't even get around the problem by creating a special "access everything" segment in the s_PXE data structure, because the SEGDESC_t descriptors are limited to 64kB in size.
Previous versions of the PXE specification (e.g. WfM 1.1a) provide a separate API call, pxenv_tftp_read_file_pmode(), specifically to work around this problem. The s_PXENV_TFTP_READ_FILE_PMODE parameter block splits s_PXENV_TFTP_READ_FILE::Buffer into s_PXENV_TFTP_READ_FILE_PMODE::BufferSelector and s_PXENV_TFTP_READ_FILE_PMODE::BufferOffset, i.e. it provides a protected-mode segment:offset address for the data buffer. This API call is no longer present in version 2.1 of the PXE specification.
Etherboot makes the assumption that s_PXENV_TFTP_READ_FILE::Buffer is an offset relative to the caller's data segment, when pxenv_tftp_read_file() is called in protected mode.
On x86, you must set the s_PXE::StatusCallout field to a nonzero value before calling this function in protected mode. You cannot call this function with a 32-bit stack segment. (See the relevant implementation note for more details.)
Definition at line 471 of file pxe_tftp.c.
References pxe_tftp_connection::buffer, s_PXENV_TFTP_READ_FILE::Buffer, s_PXENV_TFTP_READ_FILE::BufferSize, DBG, EINPROGRESS, s_PXENV_TFTP_READ_FILE::FileName, pxe_tftp_connection::max_offset, phys_to_user(), pxe_tftp_close(), pxe_tftp_open(), PXENV_EXIT_FAILURE, PXENV_EXIT_SUCCESS, PXENV_STATUS, pxe_tftp_connection::rc, s_PXENV_TFTP_READ_FILE::ServerIPAddress, pxe_tftp_connection::size, s_PXENV_TFTP_READ_FILE::Status, step(), and UNULL.
Referenced by pxe_api_call(), and pxenv_restart_tftp().
00472 { 00473 int rc; 00474 00475 DBG ( "PXENV_TFTP_READ_FILE to %08x+%x", tftp_read_file->Buffer, 00476 tftp_read_file->BufferSize ); 00477 00478 /* Open TFTP file */ 00479 if ( ( rc = pxe_tftp_open ( tftp_read_file->ServerIPAddress, 0, 00480 tftp_read_file->FileName, 0, 0 ) ) != 0 ) { 00481 tftp_read_file->Status = PXENV_STATUS ( rc ); 00482 return PXENV_EXIT_FAILURE; 00483 } 00484 00485 /* Read entire file */ 00486 pxe_tftp.buffer = phys_to_user ( tftp_read_file->Buffer ); 00487 pxe_tftp.size = tftp_read_file->BufferSize; 00488 while ( ( rc = pxe_tftp.rc ) == -EINPROGRESS ) 00489 step(); 00490 pxe_tftp.buffer = UNULL; 00491 tftp_read_file->BufferSize = pxe_tftp.max_offset; 00492 00493 /* Close TFTP file */ 00494 pxe_tftp_close ( rc ); 00495 00496 tftp_read_file->Status = PXENV_STATUS ( rc ); 00497 return ( rc ? PXENV_EXIT_FAILURE : PXENV_EXIT_SUCCESS ); 00498 }
1.5.7.1