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+/*
+
+bufaux.c
+
+Author: Tatu Ylonen <ylo@cs.hut.fi>
+
+Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+                   All rights reserved
+
+Created: Wed Mar 29 02:24:47 1995 ylo
+
+Auxiliary functions for storing and retrieving various data types to/from
+Buffers.
+
+*/
+
+#include "includes.h"
+RCSID("$Id: bufaux.c,v 1.1 1999/10/27 03:42:43 damien Exp $");
+
+#include "ssh.h"
+#include <openssl/bn.h>
+#include "bufaux.h"
+#include "xmalloc.h"
+#include "getput.h"
+
+/* Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed
+   by (bits+7)/8 bytes of binary data, msb first. */
+
+void
+buffer_put_bignum(Buffer *buffer, BIGNUM *value)
+{
+  int bits = BN_num_bits(value);
+  int bin_size = (bits + 7) / 8;
+  char *buf = xmalloc(bin_size);
+  int oi;
+  char msg[2];
+  
+  /* Get the value of in binary */
+  oi = BN_bn2bin(value, buf);
+  assert(oi == bin_size);
+
+  /* Store the number of bits in the buffer in two bytes, msb first. */
+  PUT_16BIT(msg, bits);
+  buffer_append(buffer, msg, 2);
+  /* Store the binary data. */
+  buffer_append(buffer, buf, oi);
+  /* Clear the temporary data. */
+  memset(buf, 0, bin_size);
+  xfree(buf);
+}
+
+/* Retrieves an BIGNUM from the buffer. */
+
+int
+buffer_get_bignum(Buffer *buffer, BIGNUM *value)
+{
+  int bits, bytes;
+  unsigned char buf[2], *bin;
+
+  /* Get the number for bits. */
+  buffer_get(buffer, (char *)buf, 2);
+  bits = GET_16BIT(buf);
+  /* Compute the number of binary bytes that follow. */
+  bytes = (bits + 7) / 8;
+  bin = xmalloc(bytes);
+  buffer_get(buffer, bin, bytes);
+  BN_bin2bn(bin, bytes, value);
+  xfree(bin);
+
+  return 2 + bytes;
+}
+
+/* Returns an integer from the buffer (4 bytes, msb first). */
+
+unsigned int buffer_get_int(Buffer *buffer)
+{
+  unsigned char buf[4];
+  buffer_get(buffer, (char *)buf, 4);
+  return GET_32BIT(buf);
+}
+
+/* Stores an integer in the buffer in 4 bytes, msb first. */
+
+void buffer_put_int(Buffer *buffer, unsigned int value)
+{
+  char buf[4];
+  PUT_32BIT(buf, value);
+  buffer_append(buffer, buf, 4);
+}
+
+/* Returns an arbitrary binary string from the buffer.  The string cannot
+   be longer than 256k.  The returned value points to memory allocated
+   with xmalloc; it is the responsibility of the calling function to free
+   the data.  If length_ptr is non-NULL, the length of the returned data
+   will be stored there.  A null character will be automatically appended
+   to the returned string, and is not counted in length. */
+
+char *buffer_get_string(Buffer *buffer, unsigned int *length_ptr)
+{
+  unsigned int len;
+  char *value;
+  /* Get the length. */
+  len = buffer_get_int(buffer);
+  if (len > 256*1024)
+    fatal("Received packet with bad string length %d", len);
+  /* Allocate space for the string.  Add one byte for a null character. */
+  value = xmalloc(len + 1);
+  /* Get the string. */
+  buffer_get(buffer, value, len);
+  /* Append a null character to make processing easier. */
+  value[len] = 0;
+  /* Optionally return the length of the string. */
+  if (length_ptr)
+    *length_ptr = len;
+  return value;
+}
+
+/* Stores and arbitrary binary string in the buffer. */
+
+void buffer_put_string(Buffer *buffer, const void *buf, unsigned int len)
+{
+  buffer_put_int(buffer, len);
+  buffer_append(buffer, buf, len);
+}
+
+/* Returns a character from the buffer (0 - 255). */
+
+int buffer_get_char(Buffer *buffer)
+{
+  char ch;
+  buffer_get(buffer, &ch, 1);
+  return (unsigned char)ch;
+}
+
+/* Stores a character in the buffer. */
+
+void buffer_put_char(Buffer *buffer, int value)
+{
+  char ch = value;
+  buffer_append(buffer, &ch, 1);
+}