diff --git a/src/common/request.c b/src/common/request.c
--- a/src/common/request.c
+++ b/src/common/request.c
@@ -19,8 +19,12 @@
 
 #include "common/config.h"
 
+#include "common/request.h"
+
 #include "common/protocol.h"
 
+#include <arpa/inet.h>
+#include <openssl/evp.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -79,3 +83,230 @@ int distren_request_poing(struct distren
 
   return 0;
 }
+
+/*
+ * file posting stuffs
+ */
+struct distren_request_file_post_context
+{
+  EVP_MD_CTX *digest_ctx;
+  /* stored in network-byte order */
+  uint32_t post_id;
+};
+
+/**
+ * Helper for distren_request_file_post_start() and
+ * distren_request_parse_file_post_start().
+ */
+static int _distren_request_file_post_context_new(distren_request_file_post_context_t *post_context,
+						  uint32_t post_id)
+{
+  *post_context = malloc(sizeof(struct distren_request_file_post_context));
+  if(!*post_context)
+    return 1;
+
+  (*post_context)->post_id = htonl(post_id);
+  (*post_context)->digest_ctx = EVP_MD_CTX_create();
+  EVP_DigestInit_ex((*post_context)->digest_ctx, EVP_sha1(), NULL);
+
+  return 0;
+}
+
+/**
+ * Frees a post_context and sets the pointer to NULL.
+ */
+static int _distren_request_file_post_context_free(distren_request_file_post_context_t *post_context)
+{
+  if(!*post_context)
+    return 0;
+
+  EVP_MD_CTX_destroy((*post_context)->digest_ctx);
+  free(*post_context);
+
+  *post_context = NULL;
+
+  return 0;
+}
+
+int distren_request_file_post_context_free(distren_request_file_post_context_t post_context)
+{
+  /*
+   * for the ``public'' function, we don't need to have post_context
+   * set to NULL. Thus, we have this wrapper around
+   * _distren_request_file_post_context_free().
+   */
+  return _distren_request_file_post_context_free(&post_context);
+}
+
+int distren_request_file_post_start(struct distren_request **req,
+				    void **data,
+				    distren_request_file_post_context_t *post_context,
+				    uint32_t post_id,
+				    const char *filename)
+{
+  struct distren_request_file_post_start *file_post_start;
+
+  distren_request_new(req, sizeof(struct distren_request_file_post_start), DISTREN_REQUEST_FILE_POST_START);
+  file_post_start = malloc(sizeof(struct distren_request_file_post_start));
+  _distren_request_file_post_context_new(post_context, post_id);
+  if(!*req
+     || !file_post_start)
+    {
+      if(*req)
+	distren_request_free(*req);
+      free(file_post_start);
+      _distren_request_file_post_context_free(post_context);
+      return 1;
+    }
+
+  file_post_start->post_id = (*post_context)->post_id;
+  strncpy(file_post_start->filename, filename, DISTREN_REQUEST_FILE_POST_NAME_LEN);
+
+  *data = file_post_start;
+  return 0;
+}
+
+int distren_request_parse_file_post_start(struct distren_request *req,
+					  void *data,
+					  distren_request_file_post_context_t *post_context,
+					  uint32_t *post_id,
+					  char **filename)
+{
+  int tmp;
+  struct distren_request_file_post_start *file_post_start;
+
+  /* keep our promises ;-) */
+  *post_context = NULL;
+  *filename = NULL;
+
+  if(req->len < sizeof(struct distren_request_file_post_start))
+    return 1;
+
+  file_post_start = data;
+
+  tmp = _distren_request_file_post_context_new(post_context, file_post_start->post_id);
+  *filename = malloc(DISTREN_REQUEST_FILE_POST_NAME_LEN + 1);
+  if(tmp
+     || !*filename)
+    {
+      _distren_request_file_post_context_free(post_context);
+      free(*filename);
+    }
+
+  memcpy(*filename, file_post_start->filename, DISTREN_REQUEST_FILE_POST_NAME_LEN);
+  (*filename)[DISTREN_REQUEST_FILE_POST_NAME_LEN] = '\0';
+
+  *post_id = ntohl(file_post_start->post_id);
+
+  return 0;
+}
+
+int distren_request_file_post(struct distren_request **req,
+			      struct distren_request_file_post *data_header,
+			      distren_request_file_post_context_t post_context,
+			      const void *data,
+			      size_t len)
+{
+  distren_request_new(req, sizeof(struct distren_request_file_post) + len, DISTREN_REQUEST_FILE_POST);
+  if(!*req)
+    return 1;
+
+  data_header->post_id = post_context->post_id;
+
+  EVP_DigestUpdate(post_context->digest_ctx, data, len);
+
+  return 0;
+}
+
+int distren_request_parse_file_post(struct distren_request *req,
+				    void *data,
+				    uint32_t *post_id,
+				    distren_request_parse_file_post_find_context_func_t find_context_func,
+				    void *find_post_context_data,
+				    void **file_data,
+				    size_t *file_data_len)
+{
+  struct distren_request_file_post *file_post;
+  distren_request_file_post_context_t post_context;
+
+  if(req->type != DISTREN_REQUEST_FILE_POST
+     || req->len < sizeof(struct distren_request_file_post))
+    return 1;
+
+  file_post = data;
+  *post_id = ntohl(file_post->post_id);
+  post_context = (*find_context_func)(*post_id, find_post_context_data);
+  if(!post_context
+     || *post_id != post_context->post_id)
+    return 1;
+
+  *file_data = data + sizeof(struct distren_request_file_post);
+  *file_data_len = req->len - sizeof(struct distren_request_file_post);
+  EVP_DigestUpdate(post_context->digest_ctx, *file_data, *file_data_len);
+
+  return 0;
+}
+
+int distren_request_file_post_finish(struct distren_request **req,
+				     void **data,
+				     distren_request_file_post_context_t post_context,
+				     uint32_t cancel)
+{
+  struct distren_request_file_post_finish *file_post_finish;
+
+  distren_request_new(req, sizeof(struct distren_request_file_post_finish), DISTREN_REQUEST_FILE_POST_FINISH);
+  file_post_finish = malloc(sizeof(struct distren_request_file_post_finish));
+  if(!*req
+     || !file_post_finish)
+    {
+      if(*req)
+	distren_request_free(*req);
+      free(file_post_finish);
+
+      _distren_request_file_post_context_free(&post_context);
+      return 1;
+    }
+  file_post_finish->post_id = post_context->post_id;
+  file_post_finish->cancel = htonl(cancel);
+
+  EVP_DigestFinal(post_context->digest_ctx, file_post_finish->sha, NULL);
+  _distren_request_file_post_context_free(&post_context);
+
+  *data = file_post_finish;
+  return 0;
+}
+
+int distren_request_parse_file_post_finish(struct distren_request *req,
+				    void *data,
+				    uint32_t *post_id,
+				    distren_request_parse_file_post_find_context_func_t find_context_func,
+				    void *find_post_context_data)
+{
+  struct distren_request_file_post_finish *file_post_finish;
+  distren_request_file_post_context_t post_context;
+
+  unsigned int checksum_len;
+  unsigned char checksum[EVP_MAX_MD_SIZE];
+
+  if(req->type != DISTREN_REQUEST_FILE_POST_FINISH
+     || req->len < sizeof(struct distren_request_file_post_finish))
+    return 1;
+
+  file_post_finish = data;
+  *post_id = ntohl(file_post_finish->post_id);
+  if(ntohl(file_post_finish->cancel))
+    return 2;
+
+  post_context = find_context_func(*post_id, find_post_context_data);
+  if(!post_context)
+    return 1;
+
+  /* finish up checksumming */
+  EVP_DigestFinal_ex(post_context->digest_ctx, checksum, &checksum_len);
+  if(checksum_len > EVP_MAX_MD_SIZE)
+    checksum_len = EVP_MAX_MD_SIZE;
+  if(memcmp(checksum, file_post_finish->sha, checksum_len))
+    return 3;
+
+  return 0;
+}