diff --git a/lib/buffer.c b/lib/buffer.c
new file mode 100644
index 0000000..de51ee3
--- /dev/null
+++ b/lib/buffer.c
@@ -0,0 +1,568 @@
+/*
+ * Buffering of output and input. 
+ * Copyright (C) 1998 Kunihiro Ishiguro
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2, or (at your
+ * option) any later version.
+ * 
+ * GNU Zebra is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Zebra; see the file COPYING.  If not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA. 
+ */
+
+#include <zebra.h>
+
+#include "memory.h"
+#include "buffer.h"
+
+/* Make buffer data. */
+struct buffer_data *
+buffer_data_new (size_t size)
+{
+  struct buffer_data *d;
+
+  d = XMALLOC (MTYPE_BUFFER_DATA, sizeof (struct buffer_data));
+  memset (d, 0, sizeof (struct buffer_data));
+  d->data = XMALLOC (MTYPE_BUFFER_DATA, size);
+
+  return d;
+}
+
+void
+buffer_data_free (struct buffer_data *d)
+{
+  if (d->data)
+    XFREE (MTYPE_BUFFER_DATA, d->data);
+  XFREE (MTYPE_BUFFER_DATA, d);
+}
+
+/* Make new buffer. */
+struct buffer *
+buffer_new (size_t size)
+{
+  struct buffer *b;
+
+  b = XMALLOC (MTYPE_BUFFER, sizeof (struct buffer));
+  memset (b, 0, sizeof (struct buffer));
+
+  b->size = size;
+
+  return b;
+}
+
+/* Free buffer. */
+void
+buffer_free (struct buffer *b)
+{
+  struct buffer_data *d;
+  struct buffer_data *next;
+
+  d = b->head;
+  while (d)
+    {
+      next = d->next;
+      buffer_data_free (d);
+      d = next;
+    }
+
+  d = b->unused_head;
+  while (d)
+    {
+      next = d->next;
+      buffer_data_free (d);
+      d = next;
+    }
+  
+  XFREE (MTYPE_BUFFER, b);
+}
+
+/* Make string clone. */
+char *
+buffer_getstr (struct buffer *b)
+{
+  return strdup ((char *)b->head->data);
+}
+
+/* Return 1 if buffer is empty. */
+int
+buffer_empty (struct buffer *b)
+{
+  if (b->tail == NULL || b->tail->cp == b->tail->sp)
+    return 1;
+  else
+    return 0;
+}
+
+/* Clear and free all allocated data. */
+void
+buffer_reset (struct buffer *b)
+{
+  struct buffer_data *data;
+  struct buffer_data *next;
+  
+  for (data = b->head; data; data = next)
+    {
+      next = data->next;
+      buffer_data_free (data);
+    }
+  b->head = b->tail = NULL;
+  b->alloc = 0;
+  b->length = 0;
+}
+
+/* Add buffer_data to the end of buffer. */
+void
+buffer_add (struct buffer *b)
+{
+  struct buffer_data *d;
+
+  d = buffer_data_new (b->size);
+
+  if (b->tail == NULL)
+    {
+      d->prev = NULL;
+      d->next = NULL;
+      b->head = d;
+      b->tail = d;
+    }
+  else
+    {
+      d->prev = b->tail;
+      d->next = NULL;
+
+      b->tail->next = d;
+      b->tail = d;
+    }
+
+  b->alloc++;
+}
+
+/* Write data to buffer. */
+int
+buffer_write (struct buffer *b, u_char *ptr, size_t size)
+{
+  struct buffer_data *data;
+
+  data = b->tail;
+  b->length += size;
+
+  /* We use even last one byte of data buffer. */
+  while (size)    
+    {
+      /* If there is no data buffer add it. */
+      if (data == NULL || data->cp == b->size)
+	{
+	  buffer_add (b);
+	  data = b->tail;
+	}
+
+      /* Last data. */
+      if (size <= (b->size - data->cp))
+	{
+	  memcpy ((data->data + data->cp), ptr, size);
+
+	  data->cp += size;
+	  size = 0;
+	}
+      else
+	{
+	  memcpy ((data->data + data->cp), ptr, (b->size - data->cp));
+
+	  size -= (b->size - data->cp);
+	  ptr += (b->size - data->cp);
+
+	  data->cp = b->size;
+	}
+    }
+  return 1;
+}
+
+/* Insert character into the buffer. */
+int
+buffer_putc (struct buffer *b, u_char c)
+{
+  buffer_write (b, &c, 1);
+  return 1;
+}
+
+/* Insert word (2 octets) into ther buffer. */
+int
+buffer_putw (struct buffer *b, u_short c)
+{
+  buffer_write (b, (char *)&c, 2);
+  return 1;
+}
+
+/* Put string to the buffer. */
+int
+buffer_putstr (struct buffer *b, u_char *c)
+{
+  size_t size;
+
+  size = strlen ((char *)c);
+  buffer_write (b, c, size);
+  return 1;
+}
+
+/* Flush specified size to the fd. */
+void
+buffer_flush (struct buffer *b, int fd, size_t size)
+{
+  int iov_index;
+  struct iovec *iovec;
+  struct buffer_data *data;
+  struct buffer_data *out;
+  struct buffer_data *next;
+
+  iovec = malloc (sizeof (struct iovec) * b->alloc);
+  iov_index = 0;
+
+  for (data = b->head; data; data = data->next)
+    {
+      iovec[iov_index].iov_base = (char *)(data->data + data->sp);
+
+      if (size <= (data->cp - data->sp))
+	{
+	  iovec[iov_index++].iov_len = size;
+	  data->sp += size;
+	  if (data->sp == data->cp)
+	    data = data->next;
+	  break;
+	}
+      else
+	{
+	  iovec[iov_index++].iov_len = data->cp - data->sp;
+	  size -= data->cp - data->sp;
+	  data->sp = data->cp;
+	}
+    }
+
+  /* Write buffer to the fd. */
+  writev (fd, iovec, iov_index);
+
+  /* Free printed buffer data. */
+  for (out = b->head; out && out != data; out = next)
+    {
+      next = out->next;
+      if (next)
+	next->prev = NULL;
+      else
+	b->tail = next;
+      b->head = next;
+
+      buffer_data_free (out);
+      b->alloc--;
+    }
+
+  free (iovec);
+}
+
+/* Flush all buffer to the fd. */
+int
+buffer_flush_all (struct buffer *b, int fd)
+{
+  int ret;
+  struct buffer_data *d;
+  int iov_index;
+  struct iovec *iovec;
+
+  if (buffer_empty (b))
+    return 0;
+
+  iovec = malloc (sizeof (struct iovec) * b->alloc);
+  iov_index = 0;
+
+  for (d = b->head; d; d = d->next)
+    {
+      iovec[iov_index].iov_base = (char *)(d->data + d->sp);
+      iovec[iov_index].iov_len = d->cp - d->sp;
+      iov_index++;
+    }
+  ret = writev (fd, iovec, iov_index);
+
+  free (iovec);
+
+  buffer_reset (b);
+
+  return ret;
+}
+
+/* Flush all buffer to the fd. */
+int
+buffer_flush_vty_all (struct buffer *b, int fd, int erase_flag,
+		      int no_more_flag)
+{
+  int nbytes;
+  int iov_index;
+  struct iovec *iov;
+  struct iovec small_iov[3];
+  char more[] = " --More-- ";
+  char erase[] = { 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+		   ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
+		   0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08};
+  struct buffer_data *data;
+  struct buffer_data *out;
+  struct buffer_data *next;
+
+  /* For erase and more data add two to b's buffer_data count.*/
+  if (b->alloc == 1)
+    iov = small_iov;
+  else
+    iov = XCALLOC (MTYPE_TMP, sizeof (struct iovec) * (b->alloc + 2));
+
+  data = b->head;
+  iov_index = 0;
+
+  /* Previously print out is performed. */
+  if (erase_flag)
+    {
+      iov[iov_index].iov_base = erase;
+      iov[iov_index].iov_len = sizeof erase;
+      iov_index++;
+    }
+
+  /* Output data. */
+  for (data = b->head; data; data = data->next)
+    {
+      iov[iov_index].iov_base = (char *)(data->data + data->sp);
+      iov[iov_index].iov_len = data->cp - data->sp;
+      iov_index++;
+    }
+
+  /* In case of `more' display need. */
+  if (! buffer_empty (b) && !no_more_flag)
+    {
+      iov[iov_index].iov_base = more;
+      iov[iov_index].iov_len = sizeof more;
+      iov_index++;
+    }
+
+  /* We use write or writev*/
+  nbytes = writev (fd, iov, iov_index);
+
+  /* Error treatment. */
+  if (nbytes < 0)
+    {
+      if (errno == EINTR)
+	;
+      if (errno == EWOULDBLOCK)
+	;
+    }
+
+  /* Free printed buffer data. */
+  for (out = b->head; out && out != data; out = next)
+    {
+      next = out->next;
+      if (next)
+	next->prev = NULL;
+      else
+	b->tail = next;
+      b->head = next;
+
+      buffer_data_free (out);
+      b->alloc--;
+    }
+
+  if (iov != small_iov)
+    XFREE (MTYPE_TMP, iov);
+
+  return nbytes;
+}
+
+/* Flush buffer to the file descriptor.  Mainly used from vty
+   interface. */
+int
+buffer_flush_vty (struct buffer *b, int fd, int size, 
+		  int erase_flag, int no_more_flag)
+{
+  int nbytes;
+  int iov_index;
+  struct iovec *iov;
+  struct iovec small_iov[3];
+  char more[] = " --More-- ";
+  char erase[] = { 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+		   ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
+		   0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08};
+  struct buffer_data *data;
+  struct buffer_data *out;
+  struct buffer_data *next;
+
+#ifdef  IOV_MAX
+  int iov_size;
+  int total_size;
+  struct iovec *c_iov;
+  int c_nbytes;
+#endif /* IOV_MAX */
+
+  /* For erase and more data add two to b's buffer_data count.*/
+  if (b->alloc == 1)
+    iov = small_iov;
+  else
+    iov = XCALLOC (MTYPE_TMP, sizeof (struct iovec) * (b->alloc + 2));
+
+  data = b->head;
+  iov_index = 0;
+
+  /* Previously print out is performed. */
+  if (erase_flag)
+    {
+      iov[iov_index].iov_base = erase;
+      iov[iov_index].iov_len = sizeof erase;
+      iov_index++;
+    }
+
+  /* Output data. */
+  for (data = b->head; data; data = data->next)
+    {
+      iov[iov_index].iov_base = (char *)(data->data + data->sp);
+
+      if (size <= (data->cp - data->sp))
+	{
+	  iov[iov_index++].iov_len = size;
+	  data->sp += size;
+	  if (data->sp == data->cp)
+	    data = data->next;
+	  break;
+	}
+      else
+	{
+	  iov[iov_index++].iov_len = data->cp - data->sp;
+	  size -= (data->cp - data->sp);
+	  data->sp = data->cp;
+	}
+    }
+
+  /* In case of `more' display need. */
+  if (!buffer_empty (b) && !no_more_flag)
+    {
+      iov[iov_index].iov_base = more;
+      iov[iov_index].iov_len = sizeof more;
+      iov_index++;
+    }
+
+  /* We use write or writev*/
+
+#ifdef IOV_MAX
+  /* IOV_MAX are normally defined in <sys/uio.h> , Posix.1g.
+     example: Solaris2.6 are defined IOV_MAX size at 16.     */
+  c_iov = iov;
+  total_size = iov_index;
+  nbytes = 0;
+
+  while( total_size > 0 )
+    {
+       /* initialize write vector size at once */
+       iov_size = ( total_size > IOV_MAX ) ? IOV_MAX : total_size;
+
+       c_nbytes = writev (fd, c_iov, iov_size );
+
+       if( c_nbytes < 0 )
+         {
+           if(errno == EINTR)
+             ;
+             ;
+           if(errno == EWOULDBLOCK)
+             ;
+             ;
+           nbytes = c_nbytes;
+           break;
+
+         }
+
+        nbytes += c_nbytes;
+
+       /* move pointer io-vector */
+       c_iov += iov_size;
+       total_size -= iov_size;
+    }
+#else  /* IOV_MAX */
+   nbytes = writev (fd, iov, iov_index);
+
+  /* Error treatment. */
+  if (nbytes < 0)
+    {
+      if (errno == EINTR)
+	;
+      if (errno == EWOULDBLOCK)
+	;
+    }
+#endif /* IOV_MAX */
+
+  /* Free printed buffer data. */
+  for (out = b->head; out && out != data; out = next)
+    {
+      next = out->next;
+      if (next)
+	next->prev = NULL;
+      else
+	b->tail = next;
+      b->head = next;
+
+      buffer_data_free (out);
+      b->alloc--;
+    }
+
+  if (iov != small_iov)
+    XFREE (MTYPE_TMP, iov);
+
+  return nbytes;
+}
+
+/* Calculate size of outputs then flush buffer to the file
+   descriptor. */
+int
+buffer_flush_window (struct buffer *b, int fd, int width, int height, 
+		     int erase, int no_more)
+{
+  unsigned long cp;
+  unsigned long size;
+  int lp;
+  int lineno;
+  struct buffer_data *data;
+
+  if (height >= 2)
+    height--;
+
+  /* We have to calculate how many bytes should be written. */
+  lp = 0;
+  lineno = 0;
+  size = 0;
+  
+  for (data = b->head; data; data = data->next)
+    {
+      cp = data->sp;
+
+      while (cp < data->cp)
+	{
+	  if (data->data[cp] == '\n' || lp == width)
+	    {
+	      lineno++;
+	      if (lineno == height)
+		{
+		  cp++;
+		  size++;
+		  goto flush;
+		}
+	      lp = 0;
+	    }
+	  cp++;
+	  lp++;
+	  size++;
+	}
+    }
+
+  /* Write data to the file descriptor. */
+ flush:
+
+  return buffer_flush_vty (b, fd, size, erase, no_more);
+}