sshbuf.h - platform/external/openssh - Gitiles

 /*	$OpenBSD: sshbuf.h,v 1.9 2017/09/12 06:32:07 djm Exp $	*/
 /*
  * Copyright (c) 2011 Damien Miller
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */

 #ifndef _SSHBUF_H
 #define _SSHBUF_H

 #include <sys/types.h>
 #include <stdarg.h>
 #include <stdio.h>
 #ifdef WITH_OPENSSL
 # include <openssl/bn.h>
 # ifdef OPENSSL_HAS_ECC
 #  include <openssl/ec.h>
 # endif /* OPENSSL_HAS_ECC */
 #endif /* WITH_OPENSSL */

 #define SSHBUF_SIZE_MAX		0x8000000	/* Hard maximum size */
 #define SSHBUF_REFS_MAX		0x100000	/* Max child buffers */
 #define SSHBUF_MAX_BIGNUM	(16384 / 8)	/* Max bignum *bytes* */
 #define SSHBUF_MAX_ECPOINT	((528 * 2 / 8) + 1) /* Max EC point *bytes* */

 /*
  * NB. do not depend on the internals of this. It will be made opaque
  * one day.
  */
 struct sshbuf {
 	u_char *d;		/* Data */
 	const u_char *cd;	/* Const data */
 	size_t off;		/* First available byte is buf->d + buf->off */
 	size_t size;		/* Last byte is buf->d + buf->size - 1 */
 	size_t max_size;	/* Maximum size of buffer */
 	size_t alloc;		/* Total bytes allocated to buf->d */
 	int readonly;		/* Refers to external, const data */
 	int dont_free;		/* Kludge to support sshbuf_init */
 	u_int refcount;		/* Tracks self and number of child buffers */
 	struct sshbuf *parent;	/* If child, pointer to parent */
 };

 #ifndef SSHBUF_NO_DEPREACTED
 /*
  * NB. Please do not use sshbuf_init() in new code. Please use sshbuf_new()
  * instead. sshbuf_init() is deprectated and will go away soon (it is
  * only included to allow compat with buffer_* in OpenSSH)
  */
 void sshbuf_init(struct sshbuf *buf);
 #endif

 /*
  * Create a new sshbuf buffer.
  * Returns pointer to buffer on success, or NULL on allocation failure.
  */
 struct sshbuf *sshbuf_new(void);

 /*
  * Create a new, read-only sshbuf buffer from existing data.
  * Returns pointer to buffer on success, or NULL on allocation failure.
  */
 struct sshbuf *sshbuf_from(const void *blob, size_t len);

 /*
  * Create a new, read-only sshbuf buffer from the contents of an existing
  * buffer. The contents of "buf" must not change in the lifetime of the
  * resultant buffer.
  * Returns pointer to buffer on success, or NULL on allocation failure.
  */
 struct sshbuf *sshbuf_fromb(struct sshbuf *buf);

 /*
  * Create a new, read-only sshbuf buffer from the contents of a string in
  * an existing buffer (the string is consumed in the process).
  * The contents of "buf" must not change in the lifetime of the resultant
  * buffer.
  * Returns pointer to buffer on success, or NULL on allocation failure.
  */
 int	sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp);

 /*
  * Clear and free buf
  */
 void	sshbuf_free(struct sshbuf *buf);

 /*
  * Reset buf, clearing its contents. NB. max_size is preserved.
  */
 void	sshbuf_reset(struct sshbuf *buf);

 /*
  * Return the maximum size of buf
  */
 size_t	sshbuf_max_size(const struct sshbuf *buf);

 /*
  * Set the maximum size of buf
  * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
  */
 int	sshbuf_set_max_size(struct sshbuf *buf, size_t max_size);

 /*
  * Returns the length of data in buf
  */
 size_t	sshbuf_len(const struct sshbuf *buf);

 /*
  * Returns number of bytes left in buffer before hitting max_size.
  */
 size_t	sshbuf_avail(const struct sshbuf *buf);

 /*
  * Returns a read-only pointer to the start of the data in buf
  */
 const u_char *sshbuf_ptr(const struct sshbuf *buf);

 /*
  * Returns a mutable pointer to the start of the data in buf, or
  * NULL if the buffer is read-only.
  */
 u_char *sshbuf_mutable_ptr(const struct sshbuf *buf);

 /*
  * Check whether a reservation of size len will succeed in buf
  * Safer to use than direct comparisons again sshbuf_avail as it copes
  * with unsigned overflows correctly.
  * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
  */
 int	sshbuf_check_reserve(const struct sshbuf *buf, size_t len);

 /*
  * Preallocates len additional bytes in buf.
  * Useful for cases where the caller knows how many bytes will ultimately be
  * required to avoid realloc in the buffer code.
  * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
  */
 int	sshbuf_allocate(struct sshbuf *buf, size_t len);

 /*
  * Reserve len bytes in buf.
  * Returns 0 on success and a pointer to the first reserved byte via the
  * optional dpp parameter or a negative * SSH_ERR_* error code on failure.
  */
 int	sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp);

 /*
  * Consume len bytes from the start of buf
  * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
  */
 int	sshbuf_consume(struct sshbuf *buf, size_t len);

 /*
  * Consume len bytes from the end of buf
  * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
  */
 int	sshbuf_consume_end(struct sshbuf *buf, size_t len);

 /* Extract or deposit some bytes */
 int	sshbuf_get(struct sshbuf *buf, void *v, size_t len);
 int	sshbuf_put(struct sshbuf *buf, const void *v, size_t len);
 int	sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v);

 /* Append using a printf(3) format */
 int	sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)
 	    __attribute__((format(printf, 2, 3)));
 int	sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap);

 /* Functions to extract or store big-endian words of various sizes */
 int	sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp);
 int	sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp);
 int	sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp);
 int	sshbuf_get_u8(struct sshbuf *buf, u_char *valp);
 int	sshbuf_put_u64(struct sshbuf *buf, u_int64_t val);
 int	sshbuf_put_u32(struct sshbuf *buf, u_int32_t val);
 int	sshbuf_put_u16(struct sshbuf *buf, u_int16_t val);
 int	sshbuf_put_u8(struct sshbuf *buf, u_char val);

 /*
  * Functions to extract or store SSH wire encoded strings (u32 len || data)
  * The "cstring" variants admit no \0 characters in the string contents.
  * Caller must free *valp.
  */
 int	sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp);
 int	sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp);
 int	sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v);
 int	sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len);
 int	sshbuf_put_cstring(struct sshbuf *buf, const char *v);
 int	sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v);

 /*
  * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to
  * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the
  * next sshbuf-modifying function call. Caller does not free.
  */
 int	sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp,
 	    size_t *lenp);

 /* Skip past a string */
 #define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL)

 /* Another variant: "peeks" into the buffer without modifying it */
 int	sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,
 	    size_t *lenp);
 /* XXX peek_u8 / peek_u32 */

 /*
  * Functions to extract or store SSH wire encoded bignums and elliptic
  * curve points.
  */
 int	sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len);
 int	sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
 	    const u_char **valp, size_t *lenp);
 #ifdef WITH_OPENSSL
 int	sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM *v);
 int	sshbuf_get_bignum1(struct sshbuf *buf, BIGNUM *v);
 int	sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v);
 int	sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *v);
 # ifdef OPENSSL_HAS_ECC
 int	sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g);
 int	sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v);
 int	sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g);
 int	sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v);
 # endif /* OPENSSL_HAS_ECC */
 #endif /* WITH_OPENSSL */

 /* Dump the contents of the buffer in a human-readable format */
 void	sshbuf_dump(struct sshbuf *buf, FILE *f);

 /* Dump specified memory in a human-readable format */
 void	sshbuf_dump_data(const void *s, size_t len, FILE *f);

 /* Return the hexadecimal representation of the contents of the buffer */
 char	*sshbuf_dtob16(struct sshbuf *buf);

 /* Encode the contents of the buffer as base64 */
 char	*sshbuf_dtob64(struct sshbuf *buf);

 /* Decode base64 data and append it to the buffer */
 int	sshbuf_b64tod(struct sshbuf *buf, const char *b64);

 /*
  * Duplicate the contents of a buffer to a string (caller to free).
  * Returns NULL on buffer error, or if the buffer contains a premature
  * nul character.
  */
 char *sshbuf_dup_string(struct sshbuf *buf);

 /* Macros for decoding/encoding integers */
 #define PEEK_U64(p) \
 	(((u_int64_t)(((const u_char *)(p))[0]) << 56) | \
 	 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \
 	 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \
 	 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \
 	 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \
 	 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \
 	 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \
 	  (u_int64_t)(((const u_char *)(p))[7]))
 #define PEEK_U32(p) \
 	(((u_int32_t)(((const u_char *)(p))[0]) << 24) | \
 	 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \
 	 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \
 	  (u_int32_t)(((const u_char *)(p))[3]))
 #define PEEK_U16(p) \
 	(((u_int16_t)(((const u_char *)(p))[0]) << 8) | \
 	  (u_int16_t)(((const u_char *)(p))[1]))

 #define POKE_U64(p, v) \
 	do { \
 		const u_int64_t __v = (v); \
 		((u_char *)(p))[0] = (__v >> 56) & 0xff; \
 		((u_char *)(p))[1] = (__v >> 48) & 0xff; \
 		((u_char *)(p))[2] = (__v >> 40) & 0xff; \
 		((u_char *)(p))[3] = (__v >> 32) & 0xff; \
 		((u_char *)(p))[4] = (__v >> 24) & 0xff; \
 		((u_char *)(p))[5] = (__v >> 16) & 0xff; \
 		((u_char *)(p))[6] = (__v >> 8) & 0xff; \
 		((u_char *)(p))[7] = __v & 0xff; \
 	} while (0)
 #define POKE_U32(p, v) \
 	do { \
 		const u_int32_t __v = (v); \
 		((u_char *)(p))[0] = (__v >> 24) & 0xff; \
 		((u_char *)(p))[1] = (__v >> 16) & 0xff; \
 		((u_char *)(p))[2] = (__v >> 8) & 0xff; \
 		((u_char *)(p))[3] = __v & 0xff; \
 	} while (0)
 #define POKE_U16(p, v) \
 	do { \
 		const u_int16_t __v = (v); \
 		((u_char *)(p))[0] = (__v >> 8) & 0xff; \
 		((u_char *)(p))[1] = __v & 0xff; \
 	} while (0)

 /* Internal definitions follow. Exposed for regress tests */
 #ifdef SSHBUF_INTERNAL

 /*
  * Return the allocation size of buf
  */
 size_t	sshbuf_alloc(const struct sshbuf *buf);

 /*
  * Increment the reference count of buf.
  */
 int	sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent);

 /*
  * Return the parent buffer of buf, or NULL if it has no parent.
  */
 const struct sshbuf *sshbuf_parent(const struct sshbuf *buf);

 /*
  * Return the reference count of buf
  */
 u_int	sshbuf_refcount(const struct sshbuf *buf);

 # define SSHBUF_SIZE_INIT	256		/* Initial allocation */
 # define SSHBUF_SIZE_INC	256		/* Preferred increment length */
 # define SSHBUF_PACK_MIN	8192		/* Minimim packable offset */

 /* # define SSHBUF_ABORT abort */
 /* # define SSHBUF_DEBUG */

 # ifndef SSHBUF_ABORT
 #  define SSHBUF_ABORT()
 # endif

 # ifdef SSHBUF_DEBUG
 #  define SSHBUF_TELL(what) do { \
 		printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \
 		    __FILE__, __LINE__, __func__, what, \
 		    buf->size, buf->alloc, buf->off, buf->max_size); \
 		fflush(stdout); \
 	} while (0)
 #  define SSHBUF_DBG(x) do { \
 		printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \
 		printf x; \
 		printf("\n"); \
 		fflush(stdout); \
 	} while (0)
 # else
 #  define SSHBUF_TELL(what)
 #  define SSHBUF_DBG(x)
 # endif
 #endif /* SSHBUF_INTERNAL */

 #endif /* _SSHBUF_H */
	/* $OpenBSD: sshbuf.h,v 1.9 2017/09/12 06:32:07 djm Exp $ */
	/*
	* Copyright (c) 2011 Damien Miller
	*
	* Permission to use, copy, modify, and distribute this software for any
	* purpose with or without fee is hereby granted, provided that the above
	* copyright notice and this permission notice appear in all copies.
	*
	* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
	* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
	* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
	* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	*/

	#ifndef _SSHBUF_H
	#define _SSHBUF_H

	#include <sys/types.h>
	#include <stdarg.h>
	#include <stdio.h>
	#ifdef WITH_OPENSSL
	# include <openssl/bn.h>
	# ifdef OPENSSL_HAS_ECC
	# include <openssl/ec.h>
	# endif /* OPENSSL_HAS_ECC */
	#endif /* WITH_OPENSSL */

	#define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */
	#define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */
	#define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum bytes */
	#define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point bytes */

	/*
	* NB. do not depend on the internals of this. It will be made opaque
	* one day.
	*/
	struct sshbuf {
	u_char d; / Data */
	const u_char cd; / Const data */
	size_t off; /* First available byte is buf->d + buf->off */
	size_t size; /* Last byte is buf->d + buf->size - 1 */
	size_t max_size; /* Maximum size of buffer */
	size_t alloc; /* Total bytes allocated to buf->d */
	int readonly; /* Refers to external, const data */
	int dont_free; /* Kludge to support sshbuf_init */
	u_int refcount; /* Tracks self and number of child buffers */
	struct sshbuf parent; / If child, pointer to parent */
	};

	#ifndef SSHBUF_NO_DEPREACTED
	/*
	* NB. Please do not use sshbuf_init() in new code. Please use sshbuf_new()
	* instead. sshbuf_init() is deprectated and will go away soon (it is
	* only included to allow compat with buffer_* in OpenSSH)
	*/
	void sshbuf_init(struct sshbuf *buf);
	#endif

	/*
	* Create a new sshbuf buffer.
	* Returns pointer to buffer on success, or NULL on allocation failure.
	*/
	struct sshbuf *sshbuf_new(void);

	/*
	* Create a new, read-only sshbuf buffer from existing data.
	* Returns pointer to buffer on success, or NULL on allocation failure.
	*/
	struct sshbuf sshbuf_from(const void blob, size_t len);

	/*
	* Create a new, read-only sshbuf buffer from the contents of an existing
	* buffer. The contents of "buf" must not change in the lifetime of the
	* resultant buffer.
	* Returns pointer to buffer on success, or NULL on allocation failure.
	*/
	struct sshbuf sshbuf_fromb(struct sshbuf buf);

	/*
	* Create a new, read-only sshbuf buffer from the contents of a string in
	* an existing buffer (the string is consumed in the process).
	* The contents of "buf" must not change in the lifetime of the resultant
	* buffer.
	* Returns pointer to buffer on success, or NULL on allocation failure.
	*/
	int sshbuf_froms(struct sshbuf buf, struct sshbuf *bufp);

	/*
	* Clear and free buf
	*/
	void sshbuf_free(struct sshbuf *buf);

	/*
	* Reset buf, clearing its contents. NB. max_size is preserved.
	*/
	void sshbuf_reset(struct sshbuf *buf);

	/*
	* Return the maximum size of buf
	*/
	size_t sshbuf_max_size(const struct sshbuf *buf);

	/*
	* Set the maximum size of buf
	* Returns 0 on success, or a negative SSH_ERR_* error code on failure.
	*/
	int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size);

	/*
	* Returns the length of data in buf
	*/
	size_t sshbuf_len(const struct sshbuf *buf);

	/*
	* Returns number of bytes left in buffer before hitting max_size.
	*/
	size_t sshbuf_avail(const struct sshbuf *buf);

	/*
	* Returns a read-only pointer to the start of the data in buf
	*/
	const u_char sshbuf_ptr(const struct sshbuf buf);

	/*
	* Returns a mutable pointer to the start of the data in buf, or
	* NULL if the buffer is read-only.
	*/
	u_char sshbuf_mutable_ptr(const struct sshbuf buf);

	/*
	* Check whether a reservation of size len will succeed in buf
	* Safer to use than direct comparisons again sshbuf_avail as it copes
	* with unsigned overflows correctly.
	* Returns 0 on success, or a negative SSH_ERR_* error code on failure.
	*/
	int sshbuf_check_reserve(const struct sshbuf *buf, size_t len);

	/*
	* Preallocates len additional bytes in buf.
	* Useful for cases where the caller knows how many bytes will ultimately be
	* required to avoid realloc in the buffer code.
	* Returns 0 on success, or a negative SSH_ERR_* error code on failure.
	*/
	int sshbuf_allocate(struct sshbuf *buf, size_t len);

	/*
	* Reserve len bytes in buf.
	* Returns 0 on success and a pointer to the first reserved byte via the
	* optional dpp parameter or a negative * SSH_ERR_* error code on failure.
	*/
	int sshbuf_reserve(struct sshbuf buf, size_t len, u_char *dpp);

	/*
	* Consume len bytes from the start of buf
	* Returns 0 on success, or a negative SSH_ERR_* error code on failure.
	*/
	int sshbuf_consume(struct sshbuf *buf, size_t len);

	/*
	* Consume len bytes from the end of buf
	* Returns 0 on success, or a negative SSH_ERR_* error code on failure.
	*/
	int sshbuf_consume_end(struct sshbuf *buf, size_t len);

	/* Extract or deposit some bytes */
	int sshbuf_get(struct sshbuf buf, void v, size_t len);
	int sshbuf_put(struct sshbuf buf, const void v, size_t len);
	int sshbuf_putb(struct sshbuf buf, const struct sshbuf v);

	/* Append using a printf(3) format */
	int sshbuf_putf(struct sshbuf buf, const char fmt, ...)
	__attribute__((format(printf, 2, 3)));
	int sshbuf_putfv(struct sshbuf buf, const char fmt, va_list ap);

	/* Functions to extract or store big-endian words of various sizes */
	int sshbuf_get_u64(struct sshbuf buf, u_int64_t valp);
	int sshbuf_get_u32(struct sshbuf buf, u_int32_t valp);
	int sshbuf_get_u16(struct sshbuf buf, u_int16_t valp);
	int sshbuf_get_u8(struct sshbuf buf, u_char valp);
	int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val);
	int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val);
	int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val);
	int sshbuf_put_u8(struct sshbuf *buf, u_char val);

	/*
	* Functions to extract or store SSH wire encoded strings (u32 len \|\| data)
	* The "cstring" variants admit no \0 characters in the string contents.
	* Caller must free *valp.
	*/
	int sshbuf_get_string(struct sshbuf buf, u_char valp, size_t lenp);
	int sshbuf_get_cstring(struct sshbuf buf, char valp, size_t lenp);
	int sshbuf_get_stringb(struct sshbuf buf, struct sshbuf v);
	int sshbuf_put_string(struct sshbuf buf, const void v, size_t len);
	int sshbuf_put_cstring(struct sshbuf buf, const char v);
	int sshbuf_put_stringb(struct sshbuf buf, const struct sshbuf v);

	/*
	* "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to
	* avoid an malloc+memcpy. The pointer is guaranteed to be valid until the
	* next sshbuf-modifying function call. Caller does not free.
	*/
	int sshbuf_get_string_direct(struct sshbuf buf, const u_char *valp,
	size_t *lenp);

	/* Skip past a string */
	#define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL)

	/* Another variant: "peeks" into the buffer without modifying it */
	int sshbuf_peek_string_direct(const struct sshbuf buf, const u_char *valp,
	size_t *lenp);
	/* XXX peek_u8 / peek_u32 */

	/*
	* Functions to extract or store SSH wire encoded bignums and elliptic
	* curve points.
	*/
	int sshbuf_put_bignum2_bytes(struct sshbuf buf, const void v, size_t len);
	int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
	const u_char *valp, size_t lenp);
	#ifdef WITH_OPENSSL
	int sshbuf_get_bignum2(struct sshbuf buf, BIGNUM v);
	int sshbuf_get_bignum1(struct sshbuf buf, BIGNUM v);
	int sshbuf_put_bignum2(struct sshbuf buf, const BIGNUM v);
	int sshbuf_put_bignum1(struct sshbuf buf, const BIGNUM v);
	# ifdef OPENSSL_HAS_ECC
	int sshbuf_get_ec(struct sshbuf buf, EC_POINT v, const EC_GROUP *g);
	int sshbuf_get_eckey(struct sshbuf buf, EC_KEY v);
	int sshbuf_put_ec(struct sshbuf buf, const EC_POINT v, const EC_GROUP *g);
	int sshbuf_put_eckey(struct sshbuf buf, const EC_KEY v);
	# endif /* OPENSSL_HAS_ECC */
	#endif /* WITH_OPENSSL */

	/* Dump the contents of the buffer in a human-readable format */
	void sshbuf_dump(struct sshbuf buf, FILE f);

	/* Dump specified memory in a human-readable format */
	void sshbuf_dump_data(const void s, size_t len, FILE f);

	/* Return the hexadecimal representation of the contents of the buffer */
	char sshbuf_dtob16(struct sshbuf buf);

	/* Encode the contents of the buffer as base64 */
	char sshbuf_dtob64(struct sshbuf buf);

	/* Decode base64 data and append it to the buffer */
	int sshbuf_b64tod(struct sshbuf buf, const char b64);

	/*
	* Duplicate the contents of a buffer to a string (caller to free).
	* Returns NULL on buffer error, or if the buffer contains a premature
	* nul character.
	*/
	char sshbuf_dup_string(struct sshbuf buf);

	/* Macros for decoding/encoding integers */
	#define PEEK_U64(p) \
	(((u_int64_t)(((const u_char *)(p))[0]) << 56) \| \
	((u_int64_t)(((const u_char *)(p))[1]) << 48) \| \
	((u_int64_t)(((const u_char *)(p))[2]) << 40) \| \
	((u_int64_t)(((const u_char *)(p))[3]) << 32) \| \
	((u_int64_t)(((const u_char *)(p))[4]) << 24) \| \
	((u_int64_t)(((const u_char *)(p))[5]) << 16) \| \
	((u_int64_t)(((const u_char *)(p))[6]) << 8) \| \
	(u_int64_t)(((const u_char *)(p))[7]))
	#define PEEK_U32(p) \
	(((u_int32_t)(((const u_char *)(p))[0]) << 24) \| \
	((u_int32_t)(((const u_char *)(p))[1]) << 16) \| \
	((u_int32_t)(((const u_char *)(p))[2]) << 8) \| \
	(u_int32_t)(((const u_char *)(p))[3]))
	#define PEEK_U16(p) \
	(((u_int16_t)(((const u_char *)(p))[0]) << 8) \| \
	(u_int16_t)(((const u_char *)(p))[1]))

	#define POKE_U64(p, v) \
	do { \
	const u_int64_t __v = (v); \
	((u_char *)(p))[0] = (__v >> 56) & 0xff; \
	((u_char *)(p))[1] = (__v >> 48) & 0xff; \
	((u_char *)(p))[2] = (__v >> 40) & 0xff; \
	((u_char *)(p))[3] = (__v >> 32) & 0xff; \
	((u_char *)(p))[4] = (__v >> 24) & 0xff; \
	((u_char *)(p))[5] = (__v >> 16) & 0xff; \
	((u_char *)(p))[6] = (__v >> 8) & 0xff; \
	((u_char *)(p))[7] = __v & 0xff; \
	} while (0)
	#define POKE_U32(p, v) \
	do { \
	const u_int32_t __v = (v); \
	((u_char *)(p))[0] = (__v >> 24) & 0xff; \
	((u_char *)(p))[1] = (__v >> 16) & 0xff; \
	((u_char *)(p))[2] = (__v >> 8) & 0xff; \
	((u_char *)(p))[3] = __v & 0xff; \
	} while (0)
	#define POKE_U16(p, v) \
	do { \
	const u_int16_t __v = (v); \
	((u_char *)(p))[0] = (__v >> 8) & 0xff; \
	((u_char *)(p))[1] = __v & 0xff; \
	} while (0)

	/* Internal definitions follow. Exposed for regress tests */
	#ifdef SSHBUF_INTERNAL

	/*
	* Return the allocation size of buf
	*/
	size_t sshbuf_alloc(const struct sshbuf *buf);

	/*
	* Increment the reference count of buf.
	*/
	int sshbuf_set_parent(struct sshbuf child, struct sshbuf parent);

	/*
	* Return the parent buffer of buf, or NULL if it has no parent.
	*/
	const struct sshbuf sshbuf_parent(const struct sshbuf buf);

	/*
	* Return the reference count of buf
	*/
	u_int sshbuf_refcount(const struct sshbuf *buf);

	# define SSHBUF_SIZE_INIT 256 /* Initial allocation */
	# define SSHBUF_SIZE_INC 256 /* Preferred increment length */
	# define SSHBUF_PACK_MIN 8192 /* Minimim packable offset */

	/* # define SSHBUF_ABORT abort */
	/* # define SSHBUF_DEBUG */

	# ifndef SSHBUF_ABORT
	# define SSHBUF_ABORT()
	# endif

	# ifdef SSHBUF_DEBUG
	# define SSHBUF_TELL(what) do { \
	printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \
	__FILE__, __LINE__, __func__, what, \
	buf->size, buf->alloc, buf->off, buf->max_size); \
	fflush(stdout); \
	} while (0)
	# define SSHBUF_DBG(x) do { \
	printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \
	printf x; \
	printf("\n"); \
	fflush(stdout); \
	} while (0)
	# else
	# define SSHBUF_TELL(what)
	# define SSHBUF_DBG(x)
	# endif
	#endif /* SSHBUF_INTERNAL */

	#endif /* _SSHBUF_H */