u-boot/include/pxe_utils.h

/* SPDX-License-Identifier: GPL-2.0+ */

#ifndef __PXE_UTILS_H
#define __PXE_UTILS_H

#include <bootflow.h>
#include <linux/list.h>

/*
 * A note on the pxe file parser.
 *
 * We're parsing files that use syslinux grammar, which has a few quirks.
 * String literals must be recognized based on context - there is no
 * quoting or escaping support. There's also nothing to explicitly indicate
 * when a label section completes. We deal with that by ending a label
 * section whenever we see a line that doesn't include.
 *
 * As with the syslinux family, this same file format could be reused in the
 * future for non pxe purposes. The only action it takes during parsing that
 * would throw this off is handling of include files. It assumes we're using
 * pxe, and does a tftp download of a file listed as an include file in the
 * middle of the parsing operation. That could be handled by refactoring it to
 * take a 'include file getter' function.
 */

/**
 * struct pxe_label - describes a single label in a pxe file
 *
 * Create these with label_create()
 *
 * @num: String version of the ID number of the label, e.g. "1"
 * @name: name of the 'label' line
 * @menu: name of the menu as given on the 'menu label' line
 * @kernel_label: the kernel label, including FIT config if present
 * @kernel: the path to the kernel file to use for this label
 * @config: FIT configuration to use (after '#'), or NULL if none
 * @append: kernel command line to use when booting this label
 * @initrd: path to the initrd to use for this label.
 * @fdt: path to FDT to use
 * @fdtdir: path to FDT directory to use
 * @fdtoverlays: space-separated list of paths of FDT overlays to apply
 * @ipappend: flags for appending IP address (0x1) and MAC address (0x3)
 * @attempted: 0 if we haven't tried to boot this label, 1 if we have
 * @localboot: 1 if this label specified 'localboot', 0 otherwise
 * @localboot_val: value of the localboot parameter
 * @kaslrseed: 1 to generate kaslrseed from hw_rng
 * @list: lets these form a list, which a pxe_menu struct will hold.
 */
struct pxe_label {
	char num[4];
	char *name;
	char *menu;
	char *kernel_label;
	char *kernel;
	char *config;
	char *append;
	char *initrd;
	char *fdt;
	char *fdtdir;
	char *fdtoverlays;
	int ipappend;
	int attempted;
	int localboot;
	int localboot_val;
	int kaslrseed;
	struct list_head list;
};

/*
 * Describes a pxe menu as given via pxe files.
 *
 * title - the name of the menu as given by a 'menu title' line.
 * default_label - the name of the default label, if any.
 * fallback_label - the name of the fallback label, if any.
 * bmp - the bmp file name which is displayed in background
 * timeout - time in tenths of a second to wait for a user key-press before
 *           booting the default label.
 * prompt - if 0, don't prompt for a choice unless the timeout period is
 *          interrupted.  If 1, always prompt for a choice regardless of
 *          timeout.
 * labels - a list of labels defined for the menu.
 */
struct pxe_menu {
	char *title;
	char *default_label;
	char *fallback_label;
	char *bmp;
	int timeout;
	int prompt;
	struct list_head labels;
};

struct pxe_context;

/**
 * Read a file
 *
 * @ctx: PXE context
 * @file_path: Full path to filename to read
 * @addrp: On entry, address to load file or 0 to reserve an address with lmb;
 * on exit, address to which the file was loaded
 * @align: Reservation alignment, if using lmb
 * @type: File type
 * @fileszeip: Returns file size
 */
typedef int (*pxe_getfile_func)(struct pxe_context *ctx, const char *file_path,
				ulong *addrp, ulong align,
				enum bootflow_img_t type, ulong *filesizep);

/**
 * struct pxe_context - context information for PXE parsing
 *
 * @getfile: Function called by PXE to read a file
 * @userdata: Data the caller requires for @getfile
 * @allow_abs_path: true to allow absolute paths
 * @bootdir: Directory that files are loaded from ("" if no directory). This is
 *	allocated
 * @pxe_file_size: Size of the PXE file
 * @use_ipv6: TRUE : use IPv6 addressing, FALSE : use IPv4 addressing
 * @use_fallback: TRUE : use "fallback" option as default, FALSE : use
 *	"default" option as default
 * @no_boot: Stop show of actually booting and just return
 * @bflow: Bootflow being booted, or NULL if none (must be valid if @no_boot)
 * @cfg: PXE menu (NULL if not yet probed)
 *
 * The following are only used when probing for a label
 * @label: Label to process
 * @kern_addr_str: String containing kernel address (cannot be NULL)
 * @kern_addr: Kernel address (cannot be 0)
 * @kern_size: Kernel size in bytes
 * @initrd_addr: initaddr address (0 if none)
 * @initrd_size: initrd size (only used if @initrd_addr)
 * @initrd_str: initrd string to process (only used if @initrd_addr)
 * @conf_fdt_str: FDT-address string
 * @conf_fdt: FDT address
 * @restart: true to use BOOTM_STATE_RESTART instead of BOOTM_STATE_START (only
 *	supported with FIT / bootm)
 * @fake_go: Do a 'fake' boot, up to the last possible point, then return
 */
struct pxe_context {
	/**
	 * getfile() - read a file
	 *
	 * @ctx: PXE context
	 * @file_path: Path to the file
	 * @file_addr: String containing the hex address to put the file in
	 *	memory
	 * @filesizep: Returns the file size in bytes
	 * Return 0 if OK, -ve on error
	 */
	pxe_getfile_func getfile;

	void *userdata;
	bool allow_abs_path;
	char *bootdir;
	ulong pxe_file_size;
	bool use_ipv6;
	bool use_fallback;
	bool no_boot;
	struct bootflow *bflow;
	struct pxe_menu *cfg;

	/* information on the selected label to boot */
	struct pxe_label *label;
	char *kern_addr_str;
	ulong kern_addr;
	ulong kern_size;
	ulong initrd_addr;
	ulong initrd_size;
	char *initrd_str;
	char *conf_fdt_str;
	ulong conf_fdt;
	bool restart;
	bool fake_go;
};

/**
 * destroy_pxe_menu() - Destroy an allocated pxe structure
 *
 * Free the memory used by a pxe_menu and its labels
 *
 * @cfg: Config to destroy, previous returned from parse_pxefile()
 */
void destroy_pxe_menu(struct pxe_menu *cfg);

/**
 * get_pxe_file() - Read a file
 *
 * Retrieve the file at 'file_path' to the locate given by 'file_addr'. If
 * 'bootfile' was specified in the environment, the path to bootfile will be
 * prepended to 'file_path' and the resulting path will be used.
 *
 * @ctx: PXE context
 * @file_path: Path to file
 * @file_addr: Address to place file
 * Returns 1 on success, or < 0 for error
 */
int get_pxe_file(struct pxe_context *ctx, const char *file_path,
		 ulong file_addr);

/**
 * get_pxelinux_path() - Read a file from the same place as pxelinux.cfg
 *
 * Retrieves a file in the 'pxelinux.cfg' folder. Since this uses get_pxe_file()
 * to do the hard work, the location of the 'pxelinux.cfg' folder is generated
 * from the bootfile path, as described in get_pxe_file().
 *
 * @ctx: PXE context
 * @file: Relative path to file
 * @pxefile_addr_r: Address to load file
 * Returns 1 on success or < 0 on error.
 */
int get_pxelinux_path(struct pxe_context *ctx, const char *file,
		      ulong pxefile_addr_r);

/**
 * handle_pxe_menu() - Boot the system as prescribed by a pxe_menu.
 *
 * Use the menu system to either get the user's choice or the default, based
 * on config or user input.  If there is no default or user's choice,
 * attempted to boot labels in the order they were given in pxe files.
 * If the default or user's choice fails to boot, attempt to boot other
 * labels in the order they were given in pxe files.
 *
 * If this function returns, there weren't any labels that successfully
 * booted, or the user interrupted the menu selection via ctrl+c.
 *
 * @ctx: PXE context
 * @cfg: PXE menu
 */
void handle_pxe_menu(struct pxe_context *ctx, struct pxe_menu *cfg);

/**
 * parse_pxefile() - Parsing a pxe file
 *
 * This is only used for the top-level file.
 *
 * @ctx: PXE context (provided by the caller)
 * Returns NULL if there is an error, otherwise, returns a pointer to a
 * pxe_menu struct populated with the results of parsing the pxe file (and any
 * files it includes). The resulting pxe_menu struct can be free()'d by using
 * the destroy_pxe_menu() function.
 */
struct pxe_menu *parse_pxefile(struct pxe_context *ctx, ulong menucfg);

/**
 * format_mac_pxe() - Convert a MAC address to PXE format
 *
 * Convert an ethaddr from the environment to the format used by pxelinux
 * filenames based on mac addresses. Convert's ':' to '-', and adds "01-" to
 * the beginning of the ethernet address to indicate a hardware type of
 * Ethernet. Also converts uppercase hex characters into lowercase, to match
 * pxelinux's behavior.
 *
 * @outbuf: Buffer to hold the output (must hold 22 bytes)
 * @outbuf_len: Length of buffer
 * Returns 1 for success, -ENOENT if 'ethaddr' is undefined in the
 * environment, or some other value < 0 on error.
 */
int format_mac_pxe(char *outbuf, size_t outbuf_len);

/**
 * pxe_setup_ctx() - Setup a new PXE context
 *
 * @ctx: Context to set up
 * @getfile: Function to call to read a file
 * @userdata: Data the caller requires for @getfile - stored in ctx->userdata
 * @allow_abs_path: true to allow absolute paths
 * @bootfile: Bootfile whose directory loaded files are relative to, NULL if
 *	none
 * @use_ipv6: TRUE : use IPv6 addressing
 *            FALSE : use IPv4 addressing
 * @use_fallback: TRUE : Use "fallback" option instead of "default" should no
 *                       other choice be selected
 *                FALSE : Use "default" option should no other choice be
 *                        selected
 * @bflow: Bootflow to update, NULL if none
 * Return: 0 if OK, -ENOMEM if out of memory, -E2BIG if bootfile is larger than
 *	MAX_TFTP_PATH_LEN bytes
 */
int pxe_setup_ctx(struct pxe_context *ctx, pxe_getfile_func getfile,
		  void *userdata, bool allow_abs_path, const char *bootfile,
		  bool use_ipv6, bool use_fallback, struct bootflow *bflow);

/**
 * pxe_destroy_ctx() - Destroy a PXE context
 *
 * @ctx: Context to destroy
 */
void pxe_destroy_ctx(struct pxe_context *ctx);

/**
 * pxe_process() - Process a PXE file through to boot
 *
 * @ctx: PXE context created with pxe_setup_ctx()
 * @pxefile_addr_r: Address to load file
 * @prompt: Force a prompt for the user
 */
int pxe_process(struct pxe_context *ctx, ulong pxefile_addr_r, bool prompt);

/**
 * pxe_get_file_size() - Read the value of the 'filesize' environment variable
 *
 * @sizep: Place to put the value
 * Return: 0 if OK, -ENOENT if no such variable, -EINVAL if format is invalid
 */
int pxe_get_file_size(ulong *sizep);

/**
 * pxe_get() - Get the PXE file from the server
 *
 * This tries various filenames to obtain a PXE file
 *
 * @pxefile_addr_r: Address to put file
 * @bootdirp: Returns the boot filename, or NULL if none. This is the 'bootfile'
 *	option provided by the DHCP server. If none, returns NULL. For example,
 *	"rpi/info", which indicates that all files should be fetched from the
 *	"rpi/" subdirectory
 * @sizep: Size of the PXE file (not bootfile)
 * @use_ipv6: TRUE : use IPv6 addressing
 *            FALSE : use IPv4 addressing
 */
int pxe_get(ulong pxefile_addr_r, char **bootdirp, ulong *sizep, bool use_ipv6);

/**
 * pxe_probe() - Process a PXE file to find the label to boot
 *
 * This fills in the label, etc. fields in @ctx, assuming it funds something to
 * boot. Then pxe_do_boot() can be called to boot it.
 *
 * @ctx: PXE context created with pxe_setup_ctx()
 * @pxefile_addr_r: Address to load file
 * @prompt: Force a prompt for the user
 * Return: 0 if OK, -ve on error
 */
int pxe_probe(struct pxe_context *ctx, ulong pxefile_addr_r, bool prompt);

/**
 * pxe_do_boot() - Boot the selected label
 *
 * This boots the label discovered by pxe_probe()
 *
 * Return: Does not return, on success, otherwise returns a -ve error code
 */
int pxe_do_boot(struct pxe_context *ctx);

/*
 * Entry point for parsing a menu file. nest_level indicates how many times
 * we've nested in includes.  It will be 1 for the top level menu file.
 *
 * Returns 1 on success, < 0 on error.
 */
int parse_pxefile_top(struct pxe_context *ctx, char *p, ulong base,
		      struct pxe_menu *cfg, int nest_level);

/**
 * label_destroy() - free the memory used by a pxe_label
 *
 * This frees @label itself as well as memory used by its name,
 * kernel, config, append, initrd, fdt, fdtdir and fdtoverlay members, if
 * they're non-NULL.
 *
 * So - be sure to only use dynamically allocated memory for the members of
 * the pxe_label struct, unless you want to clean it up first. These are
 * currently only created by the pxe file parsing code.
 *
 * @label: Label to free
 */
void label_destroy(struct pxe_label *label);

#endif /* __PXE_UTILS_H */