Restructure

Signed-off-by: Mattias Andrée <maandree@kth.se>

10 files changed, 2060 insertions, 0 deletions

diff --git a/src/types/filter.c b/src/types/filter.c
new file mode 100644
index 0000000..e6facc9
--- /dev/null
+++ b/src/types/filter.c
@@ -0,0 +1,144 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "filter.h"
+#include "../util.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+
+
+/**
+ * Free all resources allocated to a filter.
+ * The allocation of `filter` itself is not freed.
+ * 
+ * @param  this  The filter
+ */
+void filter_destroy(struct filter* restrict this)
+{
+  free(this->class);
+  free(this->ramps);
+}
+
+
+
+#if defined(__clang__)
+# pragma GCC diagnostic ignored "-Wcast-align"
+#endif
+
+
+/**
+ * Marshal a filter
+ * 
+ * @param   this        The filter
+ * @param   buf         Output buffer for the marshalled filter,
+ *                      `NULL` just measure how large the buffers
+ *                      needs to be
+ * @param   ramps_size  The byte-size of `this->ramps`
+ * @return              The number of marshalled byte
+ */
+size_t filter_marshal(const struct filter* restrict this, void* restrict buf, size_t ramps_size)
+{
+  size_t off = 0, n;
+  char nonnulls = 0;
+  char* restrict bs = buf;
+  
+  if (bs != NULL)
+    {
+      if (this->class != NULL)  nonnulls |= 1;
+      if (this->ramps != NULL)  nonnulls |= 2;
+      *(bs + off) = nonnulls;
+    }
+  off += 1;
+  
+  if (bs != NULL)
+    *(int64_t*)(bs + off) = this->priority;
+  off += sizeof(int64_t);
+  
+  if (bs != NULL)
+    *(enum lifespan*)(bs + off) = this->lifespan;
+  off += sizeof(enum lifespan);
+  
+  if (this->class != NULL)
+    {
+      n = strlen(this->class) + 1;
+      if (bs != NULL)
+	memcpy(bs + off, this->class, n);
+      off += n;
+    }
+  
+  if (this->ramps != NULL)
+    {
+      if (bs != NULL)
+	memcpy(bs + off, this->ramps, ramps_size);
+      off += ramps_size;
+    }
+  
+  return off;
+}
+
+
+/**
+ * Unmarshal a filter
+ * 
+ * @param   this        Output for the filter
+ * @param   buf         Buffer with the marshalled filter
+ * @param   ramps_size  The byte-size of `this->ramps`
+ * @return              The number of unmarshalled bytes, 0 on error
+ */
+size_t filter_unmarshal(struct filter* restrict this, const void* restrict buf, size_t ramps_size)
+{
+  size_t off = 0, n;
+  char nonnulls = 0;
+  const char* restrict bs = buf;
+  
+  nonnulls = *(bs + off);
+  off += 1;
+  
+  this->class = NULL;
+  this->ramps = NULL;
+  
+  this->priority = *(const int64_t*)(bs + off);
+  off += sizeof(int64_t);
+  
+  this->lifespan = *(const enum lifespan*)(bs + off);
+  off += sizeof(enum lifespan);
+  
+  if (nonnulls & 1)
+    {
+      n = strlen(bs + off) + 1;
+      if (!(this->class = memdup(bs + off, n)))
+	goto fail;
+      off += n;
+    }
+  
+  if (nonnulls & 2)
+    {
+      if (!(this->ramps = memdup(bs + off, ramps_size)))
+	goto fail;
+      off += ramps_size;
+    }
+  
+  return off;
+  
+ fail:
+  free(this->class);
+  free(this->ramps);
+  return 0;
+}
+
diff --git a/src/types/filter.h b/src/types/filter.h
new file mode 100644
index 0000000..c9e01bb
--- /dev/null
+++ b/src/types/filter.h
@@ -0,0 +1,138 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef TYPES_FILTER_H
+#define TYPES_FILTER_H
+
+
+#include <stddef.h>
+#include <stdint.h>
+
+
+
+#ifndef GCC_ONLY
+# if defined(__GNUC__) && !defined(__clang__)
+#  define GCC_ONLY(...)  __VA_ARGS__
+# else
+#  define GCC_ONLY(...)  /* nothing */
+# endif
+#endif
+
+
+
+/**
+ * The lifespan of a filter
+ */
+enum lifespan
+{
+  /**
+   * The filter should be applied
+   * until it is explicitly removed
+   */
+  LIFESPAN_UNTIL_REMOVAL,
+  
+  /**
+   * The filter should be applied
+   * until the client exists
+   */
+  LIFESPAN_UNTIL_DEATH,
+  
+  /**
+   * The filter should be removed now
+   */
+  LIFESPAN_REMOVE
+  
+};
+
+
+/**
+ * Information about a filter
+ */
+struct filter
+{
+  /**
+   * The client that applied it. This need not be
+   * set unless `.lifespan == LIFESPAN_UNTIL_DEATH`
+   * and unless the process itself added this.
+   * This is the file descriptor of the client's
+   * connection.
+   */
+  int client;
+  
+  /**
+   * The lifespan of the filter
+   */
+  enum lifespan lifespan;
+  
+  /**
+   * The priority of the filter
+   */
+  int64_t priority;
+  
+  /**
+   * Identifier for the filter
+   */
+  char* class;
+  
+  /**
+   * The gamma ramp adjustments for the filter.
+   * This is raw binary data. `NULL` iff
+   * `lifespan == LIFESPAN_REMOVE`.
+   */
+  void* ramps;
+  
+};
+
+
+
+/**
+ * Free all resources allocated to a filter.
+ * The allocation of `filter` itself is not freed.
+ * 
+ * @param  this  The filter
+ */
+GCC_ONLY(__attribute__((nonnull)))
+void filter_destroy(struct filter* restrict this);
+
+/**
+ * Marshal a filter
+ * 
+ * @param   this        The filter
+ * @param   buf         Output buffer for the marshalled filter,
+ *                      `NULL` just measure how large the buffers
+ *                      needs to be
+ * @param   ramps_size  The byte-size of `filter->ramps`
+ * @return              The number of marshalled byte
+ */
+GCC_ONLY(__attribute__((nonnull(1))))
+size_t filter_marshal(const struct filter* restrict this, void* restrict buf, size_t ramps_size);
+
+/**
+ * Unmarshal a filter
+ * 
+ * @param   this        Output for the filter, `.red_size`, `.green_size`,
+ *                      and `.blue_size` must already be set
+ * @param   buf         Buffer with the marshalled filter
+ * @param   ramps_size  The byte-size of `filter->ramps`
+ * @return              The number of unmarshalled bytes, 0 on error
+ */
+GCC_ONLY(__attribute__((nonnull)))
+size_t filter_unmarshal(struct filter* restrict this, const void* restrict buf, size_t ramps_size);
+
+
+#endif
+
diff --git a/src/types/message.c b/src/types/message.c
new file mode 100644
index 0000000..e7c844d
--- /dev/null
+++ b/src/types/message.c
@@ -0,0 +1,572 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "message.h"
+#include "../util.h"
+
+#include <sys/socket.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+
+/**
+ * Initialise a message slot so that it can
+ * be used by to read messages
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @return        Non-zero on error, `errno` will be set accordingly
+ */
+int message_initialise(struct message* restrict this)
+{
+  this->headers = NULL;
+  this->header_count = 0;
+  this->payload = NULL;
+  this->payload_size = 0;
+  this->payload_ptr = 0;
+  this->buffer_size = 128;
+  this->buffer_ptr = 0;
+  this->stage = 0;
+  this->buffer = malloc(this->buffer_size);
+  if (this->buffer == NULL)
+    return -1;
+  return 0;
+}
+
+
+/**
+ * Release all resources in a message, should
+ * be done even if initialisation fails
+ * 
+ * @param  this  The message
+ */
+void message_destroy(struct message* restrict this)
+{
+  size_t i;
+  if (this->headers != NULL)
+    for (i = 0; i < this->header_count; i++)
+      free(this->headers[i]);
+  
+  free(this->headers);
+  free(this->payload);
+  free(this->buffer);
+}
+
+
+
+#if defined(__clang__)
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wcast-align"
+#endif
+
+
+/**
+ * Marshal a message for state serialisation
+ * 
+ * @param  this  The message
+ * @param  buf   Output buffer for the marshalled data,
+ *               `NULL` just measure how large the buffers
+ *               needs to be
+ * @return       The number of marshalled byte
+ */
+size_t message_marshal(const struct message* restrict this, void* restrict buf)
+{
+  size_t i, n, off = 0;
+  char* bs = buf;
+  
+  if (bs != NULL)
+    *(size_t*)(bs + off) = this->header_count;
+  off += sizeof(size_t);
+  
+  if (bs != NULL)
+    *(size_t*)(bs + off) = this->payload_size;
+  off += sizeof(size_t);
+  
+  if (bs != NULL)
+    *(size_t*)(bs + off) = this->payload_ptr;
+  off += sizeof(size_t);
+  
+  if (bs != NULL)
+    *(size_t*)(bs + off) = this->buffer_ptr;
+  off += sizeof(size_t);
+  
+  if (bs != NULL)
+    *(int*)(bs + off) = this->stage;
+  off += sizeof(int);
+  
+  for (i = 0; i < this->header_count; i++)
+    {
+      n = strlen(this->headers[i]) + 1;
+      if (bs != NULL)
+	memcpy(bs + off, this->headers[i], n);
+      off += n;
+    }
+  
+  if (bs != NULL)
+    memcpy(bs + off, this->payload, this->payload_ptr);
+  off += this->payload_ptr;
+  
+  if (bs != NULL)
+    memcpy(bs + off, this->buffer, this->buffer_ptr);
+  off += this->buffer_ptr;
+  
+  return off;
+}
+
+
+/**
+ * Unmarshal a message for state deserialisation
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @param   buf   In buffer with the marshalled data
+ * @return        The number of unmarshalled bytes, 0 on error
+ */
+size_t message_unmarshal(struct message* restrict this, const void* restrict buf)
+{
+  size_t i, n, off = 0, header_count;
+  const char* bs = buf;
+  
+  this->header_count = 0;
+  
+  header_count = *(const size_t*)(bs + off);
+  off += sizeof(size_t);
+  
+  this->payload_size = *(const size_t*)(bs + off);
+  off += sizeof(size_t);
+  
+  this->payload_ptr = *(const size_t*)(bs + off);
+  off += sizeof(size_t);
+  
+  this->buffer_size = this->buffer_ptr = *(const size_t*)(bs + off);
+  off += sizeof(size_t);
+  
+  this->stage = *(const int*)(bs + off);
+  off += sizeof(int);
+  
+  /* Make sure that the pointers are NULL so that they are
+     not freed without being allocated when the message is
+     destroyed if this function fails. */
+  this->headers = NULL;
+  this->payload = NULL;
+  this->buffer  = NULL;
+  
+  /* To 2-power-multiple of 128 bytes. */
+  this->buffer_size >>= 7;
+  if (this->buffer_size == 0)
+    this->buffer_size = 1;
+  else
+    {
+      this->buffer_size -= 1;
+      this->buffer_size |= this->buffer_size >> 1;
+      this->buffer_size |= this->buffer_size >> 2;
+      this->buffer_size |= this->buffer_size >> 4;
+      this->buffer_size |= this->buffer_size >> 8;
+      this->buffer_size |= this->buffer_size >> 16;
+#if SIZE_MAX == UINT64_MAX
+      this->buffer_size |= this->buffer_size >> 32;
+#endif
+      this->buffer_size += 1;
+    }
+  this->buffer_size <<= 7;
+  
+  /* Allocate header list, payload and read buffer. */
+  
+  if (header_count > 0)
+    if (!(this->headers = malloc(header_count * sizeof(char*))))
+      goto fail;
+  
+  if (this->payload_size > 0)
+    if (!(this->payload = malloc(this->payload_size)))
+      goto fail;
+  
+  if (!(this->buffer = malloc(this->buffer_size)))
+    goto fail;
+  
+  /* Fill the header list, payload and read buffer. */
+  
+  for (i = 0; i < header_count; i++)
+    {
+      n = strlen(bs + off) + 1;
+      this->headers[i] = memdup(bs + off, n);
+      if (this->headers[i] == NULL)
+	goto fail;
+      off += n;
+      this->header_count++;
+    }
+  
+  memcpy(this->payload, bs + off, this->payload_ptr);
+  off += this->payload_ptr;
+  
+  memcpy(this->buffer, bs + off, this->buffer_ptr);
+  off += this->buffer_ptr;
+  
+  return off;
+  
+ fail:
+  return 0;
+}
+
+
+#if defined(__clang__)
+# pragma GCC diagnostic pop
+#endif
+
+
+
+/**
+ * Extend the header list's allocation
+ * 
+ * @param   this    The message
+ * @param   extent  The number of additional entries
+ * @return          Zero on success, -1 on error
+ */
+GCC_ONLY(__attribute__((nonnull)))
+static int extend_headers(struct message* restrict this, size_t extent)
+{
+  char** new;
+  if (!(new = realloc(this->headers, (this->header_count + extent) * sizeof(char*))))
+    return -1;
+  this->headers = new;
+  return 0;
+}
+
+
+/**
+ * Extend the read buffer by way of doubling
+ * 
+ * @param   this  The message
+ * @return        Zero on success, -1 on error
+ */
+GCC_ONLY(__attribute__((nonnull)))
+static int extend_buffer(struct message* restrict this)
+{
+  char* restrict new;
+  if (!(new = realloc(this->buffer, (this->buffer_size << 1) * sizeof(char))))
+    return -1;
+  this->buffer = new;
+  this->buffer_size <<= 1;
+  return 0;
+}
+
+
+/**
+ * Reset the header list and the payload
+ * 
+ * @param  this  The message
+ */
+GCC_ONLY(__attribute__((nonnull)))
+static void reset_message(struct message* restrict this)
+{
+  size_t i;
+  if (this->headers != NULL)
+    for (i = 0; i < this->header_count; i++)
+      free(this->headers[i]);
+  free(this->headers);
+  this->headers = NULL;
+  this->header_count = 0;
+  
+  free(this->payload);
+  this->payload = NULL;
+  this->payload_size = 0;
+  this->payload_ptr = 0;
+}
+
+
+/**
+ * Read the headers the message and determine, and store, its payload's length
+ * 
+ * @param   this  The message
+ * @return        Zero on success, negative on error (malformated message: unrecoverable state)
+ */
+GCC_ONLY(__attribute__((pure, nonnull)))
+static int get_payload_length(struct message* restrict this)
+{
+  char* header;
+  size_t i;
+  
+  for (i = 0; i < this->header_count; i++)
+    if (strstr(this->headers[i], "Length: ") == this->headers[i])
+      {
+	/* Store the message length. */
+	header = this->headers[i] + strlen("Length: ");
+	this->payload_size = (size_t)atol(header);
+	
+	/* Do not except a length that is not correctly formated. */
+	for (; *header; header++)
+	  if ((*header < '0') || ('9' < *header))
+	    return -2; /* Malformated value, enters unrecoverable state. */
+	
+	/* Stop searching for the ‘Length’ header, we have found and parsed it. */
+	break;
+      }
+  
+  return 0;
+}
+
+
+/**
+ * Verify that a header is correctly formatted
+ * 
+ * @param   header  The header, must be NUL-terminated
+ * @param   length  The length of the header
+ * @return          Zero if valid, negative if invalid (malformated message: unrecoverable state)
+ */
+GCC_ONLY(__attribute__((pure, nonnull)))
+static int validate_header(const char* restrict header, size_t length)
+{
+  char* restrict p = memchr(header, ':', length * sizeof(char));
+  
+  if (verify_utf8(header, 0) < 0)
+    /* Either the string is not UTF-8, or your are under an UTF-8 attack,
+       let's just call this unrecoverable because the client will not correct. */
+    return -2;
+  
+  if ((p == NULL) || /* Buck you, rawmemchr should not segfault the program. */
+      (p[1] != ' ')) /* Also an invalid format. ' ' is mandated after the ':'. */
+    return -2;
+  
+  return 0;
+}
+
+
+/**
+ * Remove the beginning of the read buffer
+ * 
+ * @param  this        The message
+ * @param  length      The number of characters to remove  
+ * @param  update_ptr  Whether to update the buffer pointer
+ */
+GCC_ONLY(__attribute__((nonnull)))
+static void unbuffer_beginning(struct message* restrict this, size_t length, int update_ptr)
+{
+  memmove(this->buffer, this->buffer + length, (this->buffer_ptr - length) * sizeof(char));
+  if (update_ptr)
+    this->buffer_ptr -= length;
+}
+
+
+/**
+ * Remove the header–payload delimiter from the buffer,
+ * get the payload's size and allocate the payload
+ * 
+ * @param   this  The message
+ * @return        The return value follows the rules of `message_read`
+ */
+GCC_ONLY(__attribute__((nonnull)))
+static int initialise_payload(struct message* restrict this)
+{
+  /* Remove the \n (end of empty line) we found from the buffer. */
+  unbuffer_beginning(this, 1, 1);
+  
+  /* Get the length of the payload. */
+  if (get_payload_length(this) < 0)
+    return -2; /* Malformated value, enters unrecoverable state. */
+  
+  /* Allocate the payload buffer. */
+  if (this->payload_size > 0)
+    if (!(this->payload = malloc(this->payload_size)))
+      return -1;
+  
+  return 0;
+}
+
+
+/**
+ * Create a header from the buffer and store it
+ * 
+ * @param   this    The message
+ * @param   length  The length of the header, including LF-termination
+ * @return          The return value follows the rules of `message_read`
+ */
+GCC_ONLY(__attribute__((nonnull)))
+static int store_header(struct message* restrict this, size_t length)
+{
+  char* restrict header;
+  
+  /* Allocate the header. */
+  if (!(header = malloc(length))) /* Last char is a LF, which is substituted with NUL. */
+    return -1;
+  /* Copy the header data into the allocated header, */
+  memcpy(header, this->buffer, length * sizeof(char));
+  /* and NUL-terminate it. */
+  header[length - 1] = '\0';
+  
+  /* Remove the header data from the read buffer. */
+  unbuffer_beginning(this, length, 1);
+  
+  /* Make sure the the header syntax is correct so that
+     the program does not need to care about it. */
+  if (validate_header(header, length))
+    {
+      free(header);
+      return -2;
+    }
+  
+  /* Store the header in the header list. */
+  this->headers[this->header_count++] = header;
+  
+  return 0;
+}
+
+
+/**
+ * Continue reading from the socket into the buffer
+ * 
+ * @param   this  The message
+ * @param   fd    The file descriptor of the socket
+ * @return        The return value follows the rules of `message_read`
+ */
+GCC_ONLY(__attribute__((nonnull)))
+static int continue_read(struct message* restrict this, int fd)
+{
+  size_t n;
+  ssize_t got;
+  int r;
+  
+  /* Figure out how much space we have left in the read buffer. */
+  n = this->buffer_size - this->buffer_ptr;
+  
+  /* If we do not have too much left, */
+  if (n < 128)
+    {
+      /* grow the buffer, */
+      if ((r = extend_buffer(this)) < 0)
+	return r;
+      
+      /* and recalculate how much space we have left. */
+      n = this->buffer_size - this->buffer_ptr;
+    }
+  
+  /* Then read from the socket. */
+  errno = 0;
+  got = recv(fd, this->buffer + this->buffer_ptr, n, 0);
+  this->buffer_ptr += (size_t)(got < 0 ? 0 : got);
+  if (errno)
+    return -1;
+  if (got == 0)
+    {
+      errno = ECONNRESET;
+      return -1;
+    }
+  
+  return 0;
+}
+
+
+/**
+ * Read the next message from a file descriptor
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @param   fd    The file descriptor
+ * @return        0:  At least one message is available
+ *                -1: Exceptional connection:
+ *                  EINTR:        System call interrupted
+ *                  EAGAIN:       No message is available
+ *                  EWOULDBLOCK:  No message is available
+ *                  ECONNRESET:   Connection closed
+ *                  Other:        Failure
+ *                -2: Corrupt message (unrecoverable)
+ */
+GCC_ONLY(__attribute__((nonnull)))
+int message_read(struct message* restrict this, int fd)
+{
+  size_t header_commit_buffer = 0;
+  int r;
+  
+  /* If we are at stage 2, we are done and it is time to start over.
+     This is important because the function could have been interrupted. */
+  if (this->stage == 2)
+    {
+      reset_message(this);
+      this->stage = 0;
+    }
+  
+  /* Read from file descriptor until we have a full message. */
+  for (;;)
+    {
+      char* p;
+      size_t length;
+      
+      /* Stage 0: headers. */
+      /* Read all headers that we have stored into the read buffer. */
+      while ((this->stage == 0) &&
+	     ((p = memchr(this->buffer, '\n', this->buffer_ptr * sizeof(char))) != NULL))
+	if ((length = (size_t)(p - this->buffer)))
+	  {
+	    /* We have found a header. */
+	    
+	    /* On every eighth header found with this function call,
+	       we prepare the header list for eight more headers so
+	       that it does not need to be reallocated again and again. */
+	    if (header_commit_buffer == 0)
+	      if ((r = extend_headers(this, header_commit_buffer = 8)) < 0)
+		return r;
+	    
+	    /* Create and store header. */
+	    if ((r = store_header(this, length + 1)) < 0)
+	      return r;
+	    header_commit_buffer -= 1;
+	  }
+	else
+	  {
+	    /* We have found an empty line, i.e. the end of the headers. */
+	    
+	    /* Remove the header–payload delimiter from the buffer,
+	       get the payload's size and allocate the payload. */
+	    if ((r = initialise_payload(this)) < 0)
+	      return r;
+	    
+	    /* Mark end of stage, next stage is getting the payload. */
+	    this->stage = 1;
+	  }
+      
+      
+      /* Stage 1: payload. */
+      if ((this->stage == 1) && (this->payload_size > 0))
+	{
+	  /* How much of the payload that has not yet been filled. */
+	  size_t need = this->payload_size - this->payload_ptr;
+	  /* How much we have of that what is needed. */
+	  size_t move = this->buffer_ptr < need ? this->buffer_ptr : need;
+	  
+	  /* Copy what we have, and remove it from the the read buffer. */
+	  memcpy(this->payload + this->payload_ptr, this->buffer, move * sizeof(char));
+	  unbuffer_beginning(this, move, 1);
+	  
+	  /* Keep track of how much we have read. */
+	  this->payload_ptr += move;
+	}
+      if ((this->stage == 1) && (this->payload_ptr == this->payload_size))
+	{
+	  /* If we have filled the payload (or there was no payload),
+	     mark the end of this stage, i.e. that the message is
+	     complete, and return with success. */
+	  this->stage = 2;
+	  return 0;
+	}
+      
+      
+      /* If stage 1 was not completed. */
+      
+      /* Continue reading from the socket into the buffer. */
+      if ((r = continue_read(this, fd)) < 0)
+	return r;
+    }
+}
+
diff --git a/src/types/message.h b/src/types/message.h
new file mode 100644
index 0000000..00a2a50
--- /dev/null
+++ b/src/types/message.h
@@ -0,0 +1,160 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef TYPES_MESSAGE_H
+#define TYPES_MESSAGE_H
+
+
+#include <stddef.h>
+#include <limits.h>
+
+
+
+#ifndef GCC_ONLY
+# if defined(__GNUC__) && !defined(__clang__)
+#  define GCC_ONLY(...)  __VA_ARGS__
+# else
+#  define GCC_ONLY(...)  /* nothing */
+# endif
+#endif
+
+
+
+/**
+ * Message passed between a server and a client
+ */
+struct message
+{
+  /**
+   * The headers in the message, each element in this list
+   * as an unparsed header, it consists of both the header
+   * name and its associated value, joined by ": ". A header
+   * cannot be `NULL` (unless its memory allocation failed,)
+   * but `headers` itself is `NULL` if there are no headers.
+   * The "Length" header should be included in this list.
+   */
+  char** restrict headers;
+  
+  /**
+   * The number of headers in the message
+   */
+  size_t header_count;
+  
+  /**
+   * The payload of the message, `NULL` if none (of zero-length)
+   */
+  char* restrict payload;
+  
+  /**
+   * The size of the payload
+   */
+  size_t payload_size;
+  
+  /**
+   * How much of the payload that has been stored (internal data)
+   */
+  size_t payload_ptr;
+  
+  /**
+   * Internal buffer for the reading function (internal data)
+   */
+  char* restrict buffer;
+  
+  /**
+   * The size allocated to `buffer` (internal data)
+   */
+  size_t buffer_size;
+  
+  /**
+   * The number of bytes used in `buffer` (internal data)
+   */
+  size_t buffer_ptr;
+  
+  /**
+   * 0 while reading headers, 1 while reading payload, and 2 when done (internal data)
+   */
+  int stage;
+
+#if INT_MAX != LONG_MAX
+  int padding__;
+#endif
+  
+};
+
+
+
+/**
+ * Initialise a message slot so that it can
+ * be used by to read messages
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @return        Non-zero on error, `errno` will be set accordingly
+ */
+GCC_ONLY(__attribute__((nonnull)))
+int message_initialise(struct message* restrict this);
+
+/**
+ * Release all resources in a message, should
+ * be done even if initialisation fails
+ * 
+ * @param  this  The message
+ */
+GCC_ONLY(__attribute__((nonnull)))
+void message_destroy(struct message* restrict this);
+
+/**
+ * Marshal a message for state serialisation
+ * 
+ * @param  this  The message
+ * @param  buf   Output buffer for the marshalled data,
+ *               `NULL` just measure how large the buffers
+ *               needs to be
+ * @return       The number of marshalled byte
+ */
+GCC_ONLY(__attribute__((nonnull(1))))
+size_t message_marshal(const struct message* restrict this, void* restrict buf);
+
+/**
+ * Unmarshal a message for state deserialisation
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @param   buf   In buffer with the marshalled data
+ * @return        The number of unmarshalled bytes, 0 on error
+ */
+GCC_ONLY(__attribute__((nonnull)))
+size_t message_unmarshal(struct message* restrict this, const void* restrict buf);
+
+/**
+ * Read the next message from a file descriptor
+ * 
+ * @param   this  Memory slot in which to store the new message
+ * @param   fd    The file descriptor
+ * @return        0:  At least one message is available
+ *                -1: Exceptional connection:
+ *                  EINTR:        System call interrupted
+ *                  EAGAIN:       No message is available
+ *                  EWOULDBLOCK:  No message is available
+ *                  ECONNRESET:   Connection closed
+ *                  Other:        Failure
+ *                -2: Corrupt message (unrecoverable)
+ */
+GCC_ONLY(__attribute__((nonnull)))
+int message_read(struct message* restrict this, int fd);
+
+
+#endif
+
diff --git a/src/types/output.c b/src/types/output.c
new file mode 100644
index 0000000..8576baa
--- /dev/null
+++ b/src/types/output.c
@@ -0,0 +1,264 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "output.h"
+#include "../util.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+
+
+/**
+ * Free all resources allocated to an output.
+ * The allocation of `output` itself is not freed,
+ * nor is its the libgamma destroyed.
+ * 
+ * @param  this  The output
+ */
+void output_destroy(struct output* restrict this)
+{
+  size_t i;
+  
+  if (this->supported != LIBGAMMA_NO)
+    switch (this->depth)
+      {
+      case 8:
+	libgamma_gamma_ramps8_destroy(&(this->saved_ramps.u8));
+	for (i = 0; i < this->table_size; i++)
+	  libgamma_gamma_ramps8_destroy(&(this->table_sums[i].u8));
+	break;
+      case 16:
+	libgamma_gamma_ramps16_destroy(&(this->saved_ramps.u16));
+	for (i = 0; i < this->table_size; i++)
+	  libgamma_gamma_ramps16_destroy(&(this->table_sums[i].u16));
+	break;
+      case 32:
+	libgamma_gamma_ramps32_destroy(&(this->saved_ramps.u32));
+	for (i = 0; i < this->table_size; i++)
+	  libgamma_gamma_ramps32_destroy(&(this->table_sums[i].u32));
+	break;
+      case 64:
+	libgamma_gamma_ramps64_destroy(&(this->saved_ramps.u64));
+	for (i = 0; i < this->table_size; i++)
+	  libgamma_gamma_ramps64_destroy(&(this->table_sums[i].u64));
+	break;
+      case -1:
+	libgamma_gamma_rampsf_destroy(&(this->saved_ramps.f));
+	for (i = 0; i < this->table_size; i++)
+	  libgamma_gamma_rampsf_destroy(&(this->table_sums[i].f));
+	break;
+      case -2:
+	libgamma_gamma_rampsd_destroy(&(this->saved_ramps.d));
+	for (i = 0; i < this->table_size; i++)
+	  libgamma_gamma_rampsd_destroy(&(this->table_sums[i].d));
+	break;
+      default:
+	break; /* impossible */
+      }
+  
+  for (i = 0; i < this->table_size; i++)
+    filter_destroy(this->table_filters + i);
+  
+  free(this->table_filters);
+  free(this->table_sums);
+  free(this->name);
+}
+
+
+
+#if defined(__clang__)
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wcast-align"
+#endif
+
+
+/**
+ * Marshal an output
+ * 
+ * @param   this  The output
+ * @param   buf   Output buffer for the marshalled output,
+ *                `NULL` just measure how large the buffers
+ *                needs to be
+ * @return        The number of marshalled byte
+ */
+size_t output_marshal(const struct output* restrict this, void* restrict buf)
+{
+  size_t off = 0, i, n;
+  char* bs = buf;
+  
+  if (bs != NULL)
+    *(signed*)(bs + off) = this->depth;
+  off += sizeof(signed);
+  
+  if (bs != NULL)
+    *(size_t*)(bs + off) = this->red_size;
+  off += sizeof(size_t);
+  
+  if (bs != NULL)
+    *(size_t*)(bs + off) = this->green_size;
+  off += sizeof(size_t);
+  
+  if (bs != NULL)
+    *(size_t*)(bs + off) = this->blue_size;
+  off += sizeof(size_t);
+  
+  if (bs != NULL)
+    *(size_t*)(bs + off) = this->ramps_size;
+  off += sizeof(size_t);
+  
+  if (bs != NULL)
+    *(enum libgamma_decision*)(bs + off) = this->supported;
+  off += sizeof(enum libgamma_decision);
+  
+  n = strlen(this->name) + 1;
+  if (bs != NULL)
+    memcpy(bs + off, this->name, n);
+  off += n;
+  
+  off += gamma_ramps_marshal(&(this->saved_ramps), bs ? bs + off : NULL, this->ramps_size);
+  
+  if (bs != NULL)
+    *(size_t*)(bs + off) = this->table_size;
+  off += sizeof(size_t);
+  
+  for (i = 0; i < this->table_size; i++)
+    {
+      off +=      filter_marshal(this->table_filters + i, bs ? bs + off : NULL, this->ramps_size);
+      off += gamma_ramps_marshal(this->table_sums    + i, bs ? bs + off : NULL, this->ramps_size);
+    }
+  
+  return off;
+}
+
+
+/**
+ * Unmarshal an output
+ * 
+ * @param   this  Output for the output
+ * @param   buf   Buffer with the marshalled output
+ * @return        The number of unmarshalled bytes, 0 on error
+ */
+size_t output_unmarshal(struct output* restrict this, const void* restrict buf)
+{
+  size_t off = 0, i, n;
+  const char* bs = buf;
+  
+  this->crtc = NULL;
+  this->name = NULL;
+  
+  this->depth = *(const signed*)(bs + off);
+  off += sizeof(signed);
+  
+  this->red_size = *(const size_t*)(bs + off);
+  off += sizeof(size_t);
+  
+  this->green_size = *(const size_t*)(bs + off);
+  off += sizeof(size_t);
+  
+  this->blue_size = *(const size_t*)(bs + off);
+  off += sizeof(size_t);
+  
+  this->ramps_size = *(const size_t*)(bs + off);
+  off += sizeof(size_t);
+  
+  this->supported = *(const enum libgamma_decision*)(bs + off);
+  off += sizeof(enum libgamma_decision);
+  
+  n = strlen(bs + off) + 1;
+  this->name = memdup(bs + off, n);
+  if (this->name == NULL)
+    return 0;
+  
+  off += n = gamma_ramps_unmarshal(&(this->saved_ramps), bs, this->ramps_size);
+  COPY_RAMP_SIZES(&(this->saved_ramps.u8), this);
+  if (n == 0)
+    return 0;
+  
+  this->table_size = this->table_alloc = *(const size_t*)(bs + off);
+  off += sizeof(size_t);
+  if (this->table_size > 0)
+    {
+      this->table_filters = calloc(this->table_size, sizeof(*(this->table_filters)));
+      if (this->table_filters == NULL)
+	return 0;
+      this->table_sums = calloc(this->table_size, sizeof(*(this->table_sums)));
+      if (this->table_sums == NULL)
+	return 0;
+    }
+  
+  for (i = 0; i < this->table_size; i++)
+    {
+      off += n = filter_unmarshal(this->table_filters + i, bs + off, this->ramps_size);
+      if (n == 0)
+	return 0;
+      COPY_RAMP_SIZES(&(this->table_sums[i].u8), this);
+      off += n = gamma_ramps_unmarshal(this->table_sums + i, bs + off, this->ramps_size);
+      if (n == 0)
+	return 0;
+    }
+  
+  return off;
+}
+
+
+#if defined(__clang__)
+# pragma GCC diagnostic pop
+#endif
+
+
+
+/**
+ * Compare to outputs by the names of their respective CRTC:s
+ * 
+ * @param   a  Return -1 if this one is lower
+ * @param   b  Return +1 if this one is higher
+ * @return     See description of `a` and `b`,
+ *             0 if returned if they are the same
+ */
+int output_cmp_by_name(const void* restrict a, const void* restrict b)
+{
+  const char* an = ((const struct output*)a)->name;
+  const char* bn = ((const struct output*)b)->name;
+  return strcmp(an, bn);
+}
+
+
+/**
+ * Find an output by its name
+ * 
+ * @param   key   The name of the output
+ * @param   base  The array of outputs
+ * @param   n     The number of elements in `base`
+ * @return        Output find in `base`, `NULL` if not found
+ */
+struct output* output_find_by_name(const char* restrict key, struct output* restrict base, size_t n)
+{
+  struct output k;
+
+#if defined(__GNUC__)
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wcast-qual"
+#endif
+  k.name = (char*)key;
+#if defined(__GNUC__)
+# pragma GCC diagnostic pop
+#endif
+  
+  return bsearch(&k, base, n, sizeof(*base), output_cmp_by_name);
+}
+
diff --git a/src/types/output.h b/src/types/output.h
new file mode 100644
index 0000000..f8a4c3e
--- /dev/null
+++ b/src/types/output.h
@@ -0,0 +1,206 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef TYPES_OUTPUT_H
+#define TYPES_OUTPUT_H
+
+
+#include <stddef.h>
+
+#include <libgamma.h>
+
+#include "ramps.h"
+#include "filter.h"
+
+
+
+#ifndef GCC_ONLY
+# if defined(__GNUC__) && !defined(__clang__)
+#  define GCC_ONLY(...)  __VA_ARGS__
+# else
+#  define GCC_ONLY(...)  /* nothing */
+# endif
+#endif
+
+
+
+/**
+ * Copy the ramp sizes
+ * 
+ * This macro supports both `struct output`
+ * and `struct gamma_ramps`
+ * 
+ * @param  dest  The destination
+ * @param  src   The source
+ */
+#define COPY_RAMP_SIZES(dest, src)         \
+  ((dest)->red_size   = (src)->red_size,   \
+   (dest)->green_size = (src)->green_size, \
+   (dest)->blue_size  = (src)->blue_size)
+
+
+
+/**
+ * Information about an output
+ */
+struct output
+{
+  /**
+   * -2: double
+   * -1: float
+   *  8: uint8_t
+   * 16: uint16_t
+   * 32: uint32_t
+   * 64: uint64_t
+   */
+  signed depth;
+  
+  /**
+   * Whether gamma ramps are supported
+   */
+  enum libgamma_decision supported;
+  
+  /**
+   * The number of stops in the red gamma ramp
+   */
+  size_t red_size;
+  
+  /**
+   * The number of stops in the green gamma ramp
+   */
+  size_t green_size;
+  
+  /**
+   * The number of stops in the blue gamma ramp
+   */
+  size_t blue_size;
+  
+  /**
+   * `.red_size + .green_size + .blue_size`
+   * multiplied by the byte-size of each stop
+   */
+  size_t ramps_size;
+  
+  /**
+   * The name of the output, will be its EDID
+   * if available, otherwise it will be the
+   * index of the partition, followed by a dot
+   * and the index of the CRTC within the
+   * partition, or if a name for the connector
+   * is available: the index of the partition
+   * followed by a dot and the name of the
+   * connector
+   */
+  char* restrict name;
+  
+  /**
+   * The libgamma state for the output
+   */
+  libgamma_crtc_state_t* restrict crtc;
+  
+  /**
+   * Saved gamma ramps
+   */
+  union gamma_ramps saved_ramps;
+  
+  /**
+   * The table of all applied filters
+   */
+  struct filter* restrict table_filters;
+  
+  /**
+   * `.table_sums[i]` is the resulting
+   * adjustment made when all filter
+   * from `.table_filters[0]` up to and
+   * including `.table_filters[i]` has
+   * been applied
+   */
+  union gamma_ramps* restrict table_sums;
+  
+  /**
+   * The number of elements allocated
+   * for `.table_filters` and for `.table_sums`
+   */
+  size_t table_alloc;
+  
+  /**
+   * The number of elements stored in
+   * `.table_filters` and in `.table_sums`
+   */
+  size_t table_size;
+  
+};
+
+
+
+/**
+ * Free all resources allocated to an output.
+ * The allocation of `output` itself is not freed,
+ * nor is its the libgamma destroyed.
+ * 
+ * @param  this  The output
+ */
+GCC_ONLY(__attribute__((nonnull)))
+void output_destroy(struct output* restrict this);
+
+/**
+ * Marshal an output
+ * 
+ * @param   this  The output
+ * @param   buf   Output buffer for the marshalled output,
+ *                `NULL` just measure how large the buffers
+ *                needs to be
+ * @return        The number of marshalled byte
+ */
+GCC_ONLY(__attribute__((nonnull(1))))
+size_t output_marshal(const struct output* restrict this, void* restrict buf);
+
+/**
+ * Unmarshal an output
+ * 
+ * @param   this  Output for the output
+ * @param   buf   Buffer with the marshalled output
+ * @return        The number of unmarshalled bytes, 0 on error
+ */
+GCC_ONLY(__attribute__((nonnull)))
+size_t output_unmarshal(struct output* restrict this, const void* restrict buf);
+
+/**
+ * Compare to outputs by the names of their respective CRTC:s
+ * 
+ * @param   a  Return -1 if this one is lower
+ * @param   b  Return +1 if this one is higher
+ * @return     See description of `a` and `b`,
+ *             0 if returned if they are the same
+ */
+GCC_ONLY(__attribute__((pure, nonnull)))
+int output_cmp_by_name(const void* restrict a, const void* restrict b);
+
+/**
+ * Find an output by its name
+ * 
+ * @param   key   The name of the output
+ * @param   base  The array of outputs
+ * @param   n     The number of elements in `base`
+ * @return        Output find in `base`, `NULL` if not found
+ */
+GCC_ONLY(__attribute__((pure, nonnull)))
+struct output* output_find_by_name(const char* restrict key, struct output* restrict base, size_t n);
+
+
+#endif
+
diff --git a/src/types/ramps.c b/src/types/ramps.c
new file mode 100644
index 0000000..30bed3e
--- /dev/null
+++ b/src/types/ramps.c
@@ -0,0 +1,98 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "ramps.h"
+
+#include <libclut.h>
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+
+/**
+ * The name of the process
+ */
+extern char* restrict argv0;
+
+
+
+/**
+ * Marshal a ramp trio
+ * 
+ * @param   this        The ramps
+ * @param   buf         Output buffer for the marshalled ramps,
+ *                      `NULL` just measure how large the buffers
+ *                      needs to be
+ * @param   ramps_size  The byte-size of ramps
+ * @return              The number of marshalled byte
+ */
+size_t gamma_ramps_marshal(const union gamma_ramps* restrict this, void* restrict buf, size_t ramps_size)
+{
+  if (buf != NULL)
+    memcpy(buf, this->u8.red, ramps_size);
+  return ramps_size;
+}
+
+
+/**
+ * Unmarshal a ramp trio
+ * 
+ * @param   this        Output for the ramps, `.red_size`, `.green_size`,
+ *                      and `.blue_size` must already be set
+ * @param   buf         Buffer with the marshalled ramps
+ * @param   ramps_size  The byte-size of ramps
+ * @return              The number of unmarshalled bytes, 0 on error
+ */
+size_t gamma_ramps_unmarshal(union gamma_ramps* restrict this, const void* restrict buf, size_t ramps_size)
+{
+  size_t depth = ramps_size / (this->u8.red_size + this->u8.green_size + this->u8.blue_size);
+  int r = 0;
+  switch (depth)
+    {
+    case 1:
+      r = libgamma_gamma_ramps8_initialise(&(this->u8));
+      break;
+    case 2:
+      r = libgamma_gamma_ramps16_initialise(&(this->u16));
+      break;
+    case 4:
+      r = libgamma_gamma_ramps32_initialise(&(this->u32));
+      break;
+    case 8:
+      r = libgamma_gamma_ramps64_initialise(&(this->u64));
+      break;
+    default:
+      if (depth == sizeof(float))
+	r = libgamma_gamma_rampsf_initialise(&(this->f));
+      else if (depth == sizeof(double))
+	r = libgamma_gamma_rampsd_initialise(&(this->d));
+      else
+	abort();
+      break;
+    }
+  if (r)
+    {
+      libgamma_perror(argv0, r);
+      errno = 0;
+      return 0;
+    }
+  memcpy(this->u8.red, buf, ramps_size);
+  return ramps_size;
+}
+
diff --git a/src/types/ramps.h b/src/types/ramps.h
new file mode 100644
index 0000000..001d504
--- /dev/null
+++ b/src/types/ramps.h
@@ -0,0 +1,102 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef TYPES_RAMPS_H
+#define TYPES_RAMPS_H
+
+
+#include <libgamma.h>
+
+
+
+#ifndef GCC_ONLY
+# if defined(__GNUC__) && !defined(__clang__)
+#  define GCC_ONLY(...)  __VA_ARGS__
+# else
+#  define GCC_ONLY(...)  /* nothing */
+# endif
+#endif
+
+
+
+/**
+ * Gamma ramps union for all
+ * lbigamma gamma ramps types
+ */
+union gamma_ramps
+{
+  /**
+   * Ramps with 8-bit value
+   */
+  libgamma_gamma_ramps8_t u8;
+  
+  /**
+   * Ramps with 16-bit value
+   */
+  libgamma_gamma_ramps16_t u16;
+  
+  /**
+   * Ramps with 32-bit value
+   */
+  libgamma_gamma_ramps32_t u32;
+  
+  /**
+   * Ramps with 64-bit value
+   */
+  libgamma_gamma_ramps64_t u64;
+  
+  /**
+   * Ramps with `float` value
+   */
+  libgamma_gamma_rampsf_t f;
+  
+  /**
+   * Ramps with `double` value
+   */
+  libgamma_gamma_rampsd_t d;
+  
+};
+
+
+
+/**
+ * Marshal a ramp trio
+ * 
+ * @param   this        The ramps
+ * @param   buf         Output buffer for the marshalled ramps,
+ *                      `NULL` just measure how large the buffers
+ *                      needs to be
+ * @param   ramps_size  The byte-size of ramps
+ * @return              The number of marshalled byte
+ */
+GCC_ONLY(__attribute__((nonnull(1))))
+size_t gamma_ramps_marshal(const union gamma_ramps* restrict this, void* restrict buf, size_t ramps_size);
+
+/**
+ * Unmarshal a ramp trio
+ * 
+ * @param   this        Output for the ramps
+ * @param   buf         Buffer with the marshalled ramps
+ * @param   ramps_size  The byte-size of ramps
+ * @return              The number of unmarshalled bytes, 0 on error
+ */
+GCC_ONLY(__attribute__((nonnull)))
+size_t gamma_ramps_unmarshal(union gamma_ramps* restrict this, const void* restrict buf, size_t ramps_size);
+
+
+#endif
+
diff --git a/src/types/ring.c b/src/types/ring.c
new file mode 100644
index 0000000..13cf8c9
--- /dev/null
+++ b/src/types/ring.c
@@ -0,0 +1,224 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "ring.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+
+
+/**
+ * Initialise a ring buffer
+ * 
+ * @param  this  The ring buffer
+ */
+void ring_initialise(struct ring* restrict this)
+{
+  this->start  = 0;
+  this->end    = 0;
+  this->size   = 0;
+  this->buffer = NULL;
+}
+
+
+/**
+ * Release resource allocated to a ring buffer
+ * 
+ * @param  this  The ring buffer
+ */
+void ring_destroy(struct ring* restrict this)
+{
+  free(this->buffer);
+}
+
+
+
+#if defined(__clang__)
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wcast-align"
+#endif
+
+
+/**
+ * Marshal a ring buffer
+ * 
+ * @param   this  The ring buffer
+ * @param   buf   Output buffer for the marshalled data,
+ *                `NULL` to only measure how large buffer
+ *                is needed
+ * @return        The number of marshalled bytes
+ */
+size_t ring_marshal(const struct ring* restrict this, void* restrict buf)
+{
+  size_t off = 0, n = this->end - this->start;
+  char* bs = buf;
+  
+  if (bs != NULL)
+    *(size_t*)(bs + off) = n;
+  off += sizeof(size_t);
+  
+  if (bs != NULL)
+    memcpy(bs + off, this->buffer + this->start, n);
+  off += n;
+  
+  return off;
+}
+
+
+/**
+ * Unmarshal a ring buffer
+ * 
+ * @param   this  Output parameter for the ring buffer
+ * @param   buf   Buffer with the marshalled data
+ * @return        The number of unmarshalled bytes, 0 on error
+ */
+size_t ring_unmarshal(struct ring* restrict this, const void* restrict buf)
+{
+  size_t off = 0;
+  const char* bs = buf;
+  
+  ring_initialise(this);
+  
+  this->size = this->end = *(const size_t*)(bs + off);
+  off += sizeof(size_t);
+  
+  if (this->end > 0)
+    {
+      if (!(this->buffer = malloc(this->end)))
+	return 0;
+      
+      memcpy(this->buffer, bs + off, this->end);
+      off += this->end;
+    }
+  
+  return off;
+}
+
+
+#if defined(__clang__)
+# pragma GCC diagnostic pop
+#endif
+
+
+
+/**
+ * Append data to a ring buffer
+ * 
+ * @param   this  The ring buffer
+ * @param   data  The new data
+ * @param   n     The number of bytes in `data`
+ * @return        Zero on success, -1 on error
+ */
+int ring_push(struct ring* restrict this, void* restrict data, size_t n)
+{
+  size_t used = 0;
+  
+  if (this->start == this->end)
+    {
+      if (this->buffer != NULL)
+	used = this->size;
+    }
+  else if (this->start > this->end)
+    used = this->size - this->start + this->end;
+  else
+    used = this->start - this->end;
+  
+  if (used + n > this->size)
+    {
+      char* restrict new = malloc(used + n);
+      if (new == NULL)
+	return -1;
+      if (this->buffer)
+	{
+	  if (this->start < this->end)
+	    memcpy(new, this->buffer + this->start, this->end - this->start);
+	  else
+	    {
+	      memcpy(new, this->buffer + this->start, this->size - this->start);
+	      memcpy(new + this->size - this->start, this->buffer, this->end);
+	    }
+	}
+      memcpy(new + used, data, n);
+      this->buffer = new;
+      this->start = 0;
+      this->end = used + n;
+      this->size = used + n;
+    }
+  else if ((this->start >= this->end) || (this->end + n <= this->size))
+    {
+      memcpy(this->buffer + this->end, data, n);
+      this->end += n;
+    }
+  else
+    {
+      memcpy(this->buffer + this->end, data, this->size - this->end);
+      data = (char*)data + (this->size - this->end);
+      n -= this->size - this->end;
+      memcpy(this->buffer, data, n);
+      this->end = n;
+    }
+  
+  return 0;
+}
+
+
+/**
+ * Get queued data from a ring buffer
+ * 
+ * It can take up to two calls (with `ring_pop` between)
+ * to get all queued data
+ * 
+ * @param   this  The ring buffer
+ * @param   n     Output parameter for the length
+ *                of the returned segment
+ * @return        The beginning of the queued data,
+ *                `NULL` if there is nothing more
+ */
+void* ring_peek(struct ring* restrict this, size_t* restrict n)
+{
+  if (this->buffer == NULL)
+    return *n = 0, NULL;
+  
+  if (this->start < this->end)
+    *n = this->end - this->start;
+  else
+    *n = this->size - this->start;
+  return this->buffer + this->start;
+}
+
+
+/**
+ * Dequeue data from a ring bubber
+ * 
+ * @param  this  The ring buffer
+ * @param  n     The number of bytes to dequeue
+ */
+void ring_pop(struct ring* restrict this, size_t n)
+{
+  this->start += n;
+  this->start %= this->size;
+  if (this->start == this->end)
+    {
+      free(this->buffer);
+      this->start  = 0;
+      this->end    = 0;
+      this->size   = 0;
+      this->buffer = NULL;
+    }
+}
+
diff --git a/src/types/ring.h b/src/types/ring.h
new file mode 100644
index 0000000..0474f39
--- /dev/null
+++ b/src/types/ring.h
@@ -0,0 +1,152 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef TYPES_RING_H
+#define TYPES_RING_H
+
+
+#include <stddef.h>
+
+
+
+#ifndef GCC_ONLY
+# if defined(__GNUC__) && !defined(__clang__)
+#  define GCC_ONLY(...)  __VA_ARGS__
+# else
+#  define GCC_ONLY(...)  /* nothing */
+# endif
+#endif
+
+
+
+/**
+ * Ring buffer
+ */
+struct ring
+{
+  /**
+   * Buffer for the data
+   */
+  char* restrict buffer;
+  
+  /**
+   * The first set byte in `.buffer`
+   */
+  size_t start;
+  
+  /**
+   * The last set byte in `.buffer`, plus 1
+   */
+  size_t end;
+  
+  /**
+   * The size of `.buffer`
+   */
+  size_t size;
+};
+
+
+
+/**
+ * Initialise a ring buffer
+ * 
+ * @param  this  The ring buffer
+ */
+GCC_ONLY(__attribute__((nonnull)))
+void ring_initialise(struct ring* restrict this);
+
+/**
+ * Release resource allocated to a ring buffer
+ * 
+ * @param  this  The ring buffer
+ */
+GCC_ONLY(__attribute__((nonnull)))
+void ring_destroy(struct ring* restrict this);
+
+/**
+ * Marshal a ring buffer
+ * 
+ * @param   this  The ring buffer
+ * @param   buf   Output buffer for the marshalled data,
+ *                `NULL` to only measure how large buffer
+ *                is needed
+ * @return        The number of marshalled bytes
+ */
+GCC_ONLY(__attribute__((nonnull(1))))
+size_t ring_marshal(const struct ring* restrict this, void* restrict buf);
+
+/**
+ * Unmarshal a ring buffer
+ * 
+ * @param   this  Output parameter for the ring buffer
+ * @param   buf   Buffer with the marshalled data
+ * @return        The number of unmarshalled bytes, 0 on error
+ */
+GCC_ONLY(__attribute__((nonnull)))
+size_t ring_unmarshal(struct ring* restrict this, const void* restrict buf);
+
+/**
+ * Append data to a ring buffer
+ * 
+ * @param   this  The ring buffer
+ * @param   data  The new data
+ * @param   n     The number of bytes in `data`
+ * @return        Zero on success, -1 on error
+ */
+GCC_ONLY(__attribute__((nonnull(1))))
+int ring_push(struct ring* restrict this, void* restrict data, size_t n);
+
+/**
+ * Get queued data from a ring buffer
+ * 
+ * It can take up to two calls (with `ring_pop` between)
+ * to get all queued data
+ * 
+ * @param   this  The ring buffer
+ * @param   n     Output parameter for the length
+ *                of the returned segment
+ * @return        The beginning of the queued data,
+ *                `NULL` if there is nothing more
+ */
+GCC_ONLY(__attribute__((nonnull)))
+void* ring_peek(struct ring* restrict this, size_t* restrict n);
+
+/**
+ * Dequeue data from a ring bubber
+ * 
+ * @param  this  The ring buffer
+ * @param  n     The number of bytes to dequeue
+ */
+GCC_ONLY(__attribute__((nonnull)))
+void ring_pop(struct ring* restrict this, size_t n);
+
+/**
+ * Check whether there is more data waiting
+ * in a ring buffer
+ * 
+ * @param   this  The ring buffer
+ * @return        1 if there is more data, 0 otherwise
+ */
+GCC_ONLY(__attribute__((nonnull)))
+static inline int ring_have_more(struct ring* restrict this)
+{
+  return this->buffer != NULL;
+}
+
+
+#endif
+