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Documented remainder of PXE TFTP API calls.

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This commit is contained in:
Michael Brown 2005-05-27 16:47:45 +00:00
parent 92f1a5c677
commit 59582db29d
1 changed files with 241 additions and 24 deletions
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265
src/interface/pxe/pxe_tftp.c
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@ -24,6 +24,9 @@
#include "pxe.h"
static int pxe_tftp_read_block ( unsigned char *data, unsigned int block,
unsigned int len, int eof );
/**
* TFTP OPEN
*
@ -74,6 +77,10 @@
* relevant @ref pxe_note_tftp "implementation note" for Etherboot's
* solution to this problem.
*
* 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
* @ref pxe_x86_pmode16 "implementation note" for more details.)
*
* @note If you pass in a value less than 512 for
* s_PXENV_TFTP_OPEN::PacketSize, Etherboot will attempt to negotiate
@ -89,7 +96,15 @@
* achieved without the existence of an API call %pxenv_tftp_write()
* is not made clear.
*
* Status: working
* @note Despite the existence of the numerous statements within the
* PXE specification of the form "...if a TFTP/MTFTP or UDP connection
* is active...", you cannot use pxenv_tftp_open() and
* pxenv_tftp_read() to read a file via MTFTP; only via plain old
* TFTP. If you want to use MTFTP, use pxenv_tftp_read_file()
* instead. Astute readers will note that, since
* pxenv_tftp_read_file() is an atomic operation from the point of
* view of the PXE API, it is conceptually impossible to issue any
* other PXE API call "if an MTFTP connection is active".
*/
PXENV_EXIT_t pxenv_tftp_open ( struct s_PXENV_TFTP_OPEN *tftp_open ) {
struct sockaddr_in tftp_server;
@ -134,9 +149,26 @@ PXENV_EXIT_t pxenv_tftp_open ( struct s_PXENV_TFTP_OPEN *tftp_open ) {
return PXENV_EXIT_SUCCESS;
}
/* PXENV_TFTP_CLOSE
/**
* TFTP CLOSE
*
* Status: working
* @v tftp_close Pointer to a struct s_PXENV_TFTP_CLOSE
* @ret #PXENV_EXIT_SUCCESS File was closed successfully
* @ret #PXENV_EXIT_FAILURE File was not closed
* @ret s_PXENV_TFTP_CLOSE::Status PXE status code
* @err None -
*
* Close a connection previously opened with pxenv_tftp_open(). You
* must have previously opened a connection with pxenv_tftp_open().
*
* 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
* @ref pxe_x86_pmode16 "implementation note" for more details.)
*
* @note Since TFTP runs over UDP, which is a connectionless protocol,
* the concept of closing a file is somewhat meaningless. This call
* is a no-op for Etherboot.
*/
PXENV_EXIT_t pxenv_tftp_close ( struct s_PXENV_TFTP_CLOSE *tftp_close ) {
DBG ( "PXENV_TFTP_CLOSE" );
@ -145,9 +177,71 @@ PXENV_EXIT_t pxenv_tftp_close ( struct s_PXENV_TFTP_CLOSE *tftp_close ) {
return PXENV_EXIT_SUCCESS;
}
/* PXENV_TFTP_READ
/**
* TFTP READ
*
* Status: working
* @v tftp_read Pointer to a struct s_PXENV_TFTP_READ
* @v s_PXENV_TFTP_READ::Buffer Address of data buffer
* @ret #PXENV_EXIT_SUCCESS Data was read successfully
* @ret #PXENV_EXIT_FAILURE Data was not read
* @ret s_PXENV_TFTP_READ::Status PXE status code
* @ret s_PXENV_TFTP_READ::PacketNumber TFTP packet number
* @ret s_PXENV_TFTP_READ::BufferSize Length of data written into buffer
*
* Reads a single packet from a connection previously opened with
* pxenv_tftp_open() into the data buffer pointed to by
* s_PXENV_TFTP_READ::Buffer. You must have previously opened a
* connection with pxenv_tftp_open(). The data written into
* s_PXENV_TFTP_READ::Buffer is just the file data; the various
* network headers have already been removed.
*
* The buffer must be large enough to contain a packet of the size
* negotiated via the s_PXENV_TFTP_OPEN::PacketSize field in the
* pxenv_tftp_open() call. It is worth noting that the PXE
* specification does @b not require the caller to fill in
* s_PXENV_TFTP_READ::BufferSize before calling pxenv_tftp_read(), so
* the PXE stack is free to ignore whatever value the caller might
* place there and just assume that the buffer is large enough. That
* said, it may be worth the caller always filling in
* s_PXENV_TFTP_READ::BufferSize to guard against PXE stacks that
* mistake it for an input parameter.
*
* The length of the TFTP data packet will be returned via
* s_PXENV_TFTP_READ::BufferSize. If this length is less than the
* blksize negotiated via s_PXENV_TFTP_OPEN::PacketSize in the call to
* pxenv_tftp_open(), this indicates that the block is the last block
* in the file. Note that zero is a valid length for
* s_PXENV_TFTP_READ::BufferSize, and will occur when the length of
* the file is a multiple of the blksize.
*
* The PXE specification doesn't actually state that calls to
* pxenv_tftp_read() will return the data packets in strict sequential
* order, though most PXE stacks will probably do so. The sequence
* number of the packet will be returned in
* s_PXENV_TFTP_READ::PacketNumber. The first packet in the file has
* a sequence number of one, not zero.
*
* To guard against flawed PXE stacks, the caller should probably set
* s_PXENV_TFTP_READ::PacketNumber to one less than the expected
* returned value (i.e. set it to zero for the first call to
* pxenv_tftp_read() and then re-use the returned s_PXENV_TFTP_READ
* parameter block for subsequent calls without modifying
* s_PXENV_TFTP_READ::PacketNumber between calls). The caller should
* also guard against potential problems caused by flawed
* implementations returning the occasional duplicate packet, by
* checking that the value returned in s_PXENV_TFTP_READ::PacketNumber
* is as expected (i.e. one greater than that returned from the
* previous call to pxenv_tftp_read()).
*
* Nothing in the PXE specification indicates when the TFTP
* acknowledgement packets will be sent back to the server. See the
* relevant @ref pxe_note_tftp "implementation note" for details on
* when Etherboot chooses to send these packets.
*
* 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
* @ref pxe_x86_pmode16 "implementation note" for more details.)
*/
PXENV_EXIT_t pxenv_tftp_read ( struct s_PXENV_TFTP_READ *tftp_read ) {
struct tftpblk_info_t block;
@ -180,23 +274,97 @@ PXENV_EXIT_t pxenv_tftp_read ( struct s_PXENV_TFTP_READ *tftp_read ) {
return PXENV_EXIT_SUCCESS;
}
/* PXENV_TFTP_READ_FILE
/**
* TFTP/MTFTP read file
*
* @v tftp_read_file Pointer to a struct s_PXENV_TFTP_READ_FILE
* @v s_PXENV_TFTP_READ_FILE::FileName File name
* @v s_PXENV_TFTP_READ_FILE::BufferSize Size of the receive buffer
* @v s_PXENV_TFTP_READ_FILE::Buffer Address of the receive buffer
* @v s_PXENV_TFTP_READ_FILE::ServerIPAddress TFTP server IP address
* @v s_PXENV_TFTP_READ_FILE::GatewayIPAddress Relay agent IP address
* @v s_PXENV_TFTP_READ_FILE::McastIPAddress File's multicast IP address
* @v s_PXENV_TFTP_READ_FILE::TFTPClntPort Client multicast UDP port
* @v s_PXENV_TFTP_READ_FILE::TFTPSrvPort Server multicast UDP port
* @v s_PXENV_TFTP_READ_FILE::TFTPOpenTimeOut Time to wait for first packet
* @v s_PXENV_TFTP_READ_FILE::TFTPReopenDelay MTFTP inactivity timeout
* @ret #PXENV_EXIT_SUCCESS File downloaded successfully
* @ret #PXENV_EXIT_FAILURE File not downloaded
* @ret s_PXENV_TFTP_READ_FILE::Status PXE status code
* @ret s_PXENV_TFTP_READ_FILE::BufferSize Length of downloaded file
*
* Downloads an entire file via either TFTP or MTFTP into the buffer
* pointed to by s_PXENV_TFTP_READ_FILE::Buffer.
*
* 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
* @ref pxe_routing "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
* @ref pxe_x86_pmode16 "implementation note" for more details.)
*
* @note Microsoft's NTLDR assumes that the filename passed in via
* s_PXENV_TFTP_READ_FILE::FileName will be stored in the "file" field
* of the stored DHCPACK packet, whence it will be returned via any
* subsequent calls to pxenv_get_cached_info(). Though this is
* essentially a bug in the Intel PXE implementation (not, for once,
* in the specification!), it is a bug that Microsoft relies upon, and
* so we implement this bug-for-bug compatibility by overwriting the
* filename stored DHCPACK packet with the filename passed in
* s_PXENV_TFTP_READ_FILE::FileName.
*
* Status: working
*/
int pxe_tftp_read_block ( unsigned char *data, unsigned int block __unused,
unsigned int len, int eof ) {
if ( pxe_stack->readfile.buffer ) {
if ( pxe_stack->readfile.offset + len >=
pxe_stack->readfile.bufferlen ) return -1;
memcpy ( pxe_stack->readfile.buffer +
pxe_stack->readfile.offset, data, len );
}
pxe_stack->readfile.offset += len;
return eof ? 0 : 1;
}
PXENV_EXIT_t pxenv_tftp_read_file ( struct s_PXENV_TFTP_READ_FILE
*tftp_read_file ) {
struct sockaddr_in tftp_server;
@ -233,11 +401,60 @@ PXENV_EXIT_t pxenv_tftp_read_file ( struct s_PXENV_TFTP_READ_FILE
return PXENV_EXIT_SUCCESS;
}
/* PXENV_TFTP_GET_FSIZE
static int pxe_tftp_read_block ( unsigned char *data,
unsigned int block __unused,
unsigned int len, int eof ) {
if ( pxe_stack->readfile.buffer ) {
if ( pxe_stack->readfile.offset + len >=
pxe_stack->readfile.bufferlen ) return -1;
memcpy ( pxe_stack->readfile.buffer +
pxe_stack->readfile.offset, data, len );
}
pxe_stack->readfile.offset += len;
return eof ? 0 : 1;
}
/**
* TFTP GET FILE SIZE
*
* Status: working, though ugly (we actually read the whole file,
* because it's too ugly to make Etherboot request the tsize option
* and hand it to us).
* @v tftp_get_fsize Pointer to a struct s_PXENV_TFTP_GET_FSIZE
* @v s_PXENV_TFTP_GET_FSIZE::ServerIPAddress TFTP server IP address
* @v s_PXENV_TFTP_GET_FSIZE::GatewayIPAddress Relay agent IP address
* @v s_PXENV_TFTP_GET_FSIZE::FileName File name
* @ret #PXENV_EXIT_SUCCESS File size was determined successfully
* @ret #PXENV_EXIT_FAILURE File size was not determined
* @ret s_PXENV_TFTP_GET_FSIZE::Status PXE status code
* @ret s_PXENV_TFTP_GET_FSIZE::FileSize File size
*
* Determine the size of a file on a TFTP server. This uses the
* "tsize" TFTP option, and so will not work with a TFTP server that
* does not support TFTP options, or that does not support the "tsize"
* option.
*
* The PXE specification states that this API call will @b not open a
* TFTP connection for subsequent use with pxenv_tftp_read(). (This
* is somewhat daft, since the only way to obtain the file size via
* the "tsize" option involves issuing a TFTP open request, but that's
* life.)
*
* You cannot call pxenv_tftp_get_fsize() while a TFTP or UDP
* connection is open.
*
* If s_PXENV_TFTP_GET_FSIZE::GatewayIPAddress is 0.0.0.0, normal IP
* routing will take place. See the relevant
* @ref pxe_routing "implementation note" for more details.
*
* 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
* @ref pxe_x86_pmode16 "implementation note" for more details.)
*
* @note There is no way to specify the TFTP server port with this API
* call. Though you can open a file using a non-standard TFTP server
* port (via s_PXENV_TFTP_OPEN::TFTPPort or, potentially,
* s_PXENV_TFTP_READ_FILE::TFTPSrvPort), you can only get the size of
* a file from a TFTP server listening on the standard TFTP port.
* "Consistency" is not a word in Intel's vocabulary.
*/
PXENV_EXIT_t pxenv_tftp_get_fsize ( struct s_PXENV_TFTP_GET_FSIZE
*tftp_get_fsize ) {