/*
This file is part of TALER
Copyright (C) 2014-2019 Taler Systems SA
TALER is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1,
or (at your option) any later version.
TALER 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with TALER; see the file COPYING.LGPL. If not,
see
*/
/**
* @file lib/sync_api_download.c
* @brief Implementation of the download
* @author Christian Grothoff
*/
#include "platform.h"
#include
#include
#include /* just for HTTP status codes */
#include
#include
#include
#include "sync_service.h"
#include "sync_api_curl_defaults.h"
/**
* @brief Handle for a download operation.
*/
struct SYNC_DownloadOperation
{
/**
* The url for this request.
*/
char *url;
/**
* Handle for the request.
*/
struct GNUNET_CURL_Job *job;
/**
* Reference to the execution context.
*/
struct GNUNET_CURL_Context *ctx;
/**
* Function to call with the result.
*/
SYNC_DownloadCallback cb;
/**
* Closure for @e cb.
*/
void *cb_cls;
/**
* Public key of the account we are downloading from.
*/
struct SYNC_AccountPublicKeyP account_pub;
/**
* Signature returned in the "Sync-Signature"
* header, or all zeros for none.
*/
struct SYNC_AccountSignatureP account_sig;
/**
* Hash code returned by the server in the
* "Sync-Previous" header, or all zeros for
* none.
*/
struct GNUNET_HashCode sync_previous;
};
/**
* Function called when we're done processing the
* HTTP /backup request.
*
* @param cls the `struct SYNC_DownloadOperation`
* @param response_code HTTP response code, 0 on error
* @param response
*/
static void
handle_download_finished (void *cls,
long response_code,
const void *data,
size_t data_size)
{
struct SYNC_DownloadOperation *download = cls;
download->job = NULL;
switch (response_code)
{
case 0:
break;
case MHD_HTTP_OK:
{
struct SYNC_DownloadDetails dd;
struct SYNC_UploadSignaturePS usp = {
.purpose.purpose = htonl (TALER_SIGNATURE_SYNC_BACKUP_UPLOAD),
.purpose.size = htonl (sizeof (usp)),
.old_backup_hash = download->sync_previous
};
GNUNET_CRYPTO_hash (data,
data_size,
&usp.new_backup_hash);
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_SYNC_BACKUP_UPLOAD,
&usp,
&download->account_sig.eddsa_sig,
&download->account_pub.eddsa_pub))
{
GNUNET_break_op (0);
response_code = 0;
break;
}
/* Success, call callback with all details! */
memset (&dd, 0, sizeof (dd));
dd.sig = download->account_sig;
dd.prev_backup_hash = download->sync_previous;
dd.curr_backup_hash = usp.new_backup_hash;
dd.backup = data;
dd.backup_size = data_size;
download->cb (download->cb_cls,
response_code,
&dd);
download->cb = NULL;
SYNC_download_cancel (download);
return;
}
case MHD_HTTP_BAD_REQUEST:
/* This should never happen, either us or the sync server is buggy
(or API version conflict); just pass JSON reply to the application */
break;
case MHD_HTTP_NOT_FOUND:
/* Nothing really to verify */
break;
case MHD_HTTP_INTERNAL_SERVER_ERROR:
/* Server had an internal issue; we should retry, but this API
leaves this to the application */
break;
default:
/* unexpected response code */
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Unexpected response code %u\n",
(unsigned int) response_code);
GNUNET_break (0);
response_code = 0;
break;
}
if (NULL != download->cb)
{
download->cb (download->cb_cls,
response_code,
NULL);
download->cb = NULL;
}
SYNC_download_cancel (download);
}
/**
* Handle HTTP header received by curl.
*
* @param buffer one line of HTTP header data
* @param size size of an item
* @param nitems number of items passed
* @param userdata our `struct SYNC_DownloadOperation *`
* @return `size * nitems`
*/
static size_t
handle_header (char *buffer,
size_t size,
size_t nitems,
void *userdata)
{
struct SYNC_DownloadOperation *download = userdata;
size_t total = size * nitems;
char *ndup;
const char *hdr_type;
char *hdr_val;
char *sp;
ndup = GNUNET_strndup (buffer,
total);
hdr_type = strtok_r (ndup,
":",
&sp);
if (NULL == hdr_type)
{
GNUNET_free (ndup);
return total;
}
hdr_val = strtok_r (NULL,
"\n\r",
&sp);
if (NULL == hdr_val)
{
GNUNET_free (ndup);
return total;
}
if (' ' == *hdr_val)
hdr_val++;
if (0 == strcasecmp (hdr_type,
"Sync-Signature"))
{
if (GNUNET_OK !=
GNUNET_STRINGS_string_to_data (hdr_val,
strlen (hdr_val),
&download->account_sig,
sizeof (struct SYNC_AccountSignatureP)))
{
GNUNET_break_op (0);
GNUNET_free (ndup);
return 0;
}
}
if (0 == strcasecmp (hdr_type,
"Sync-Previous"))
{
if (GNUNET_OK !=
GNUNET_STRINGS_string_to_data (hdr_val,
strlen (hdr_val),
&download->sync_previous,
sizeof (struct GNUNET_HashCode)))
{
GNUNET_break_op (0);
GNUNET_free (ndup);
return 0;
}
}
GNUNET_free (ndup);
return total;
}
/**
* Download the latest version of a backup for account @a pub.
*
* @param ctx for HTTP client request processing
* @param base_url base URL of the Sync server
* @param pub account public key
* @param cb function to call with the backup
* @param cb_cls closure for @a cb
* @return handle for the operation
*/
struct SYNC_DownloadOperation *
SYNC_download (struct GNUNET_CURL_Context *ctx,
const char *base_url,
const struct SYNC_AccountPublicKeyP *pub,
SYNC_DownloadCallback cb,
void *cb_cls)
{
struct SYNC_DownloadOperation *download;
char *pub_str;
CURL *eh;
download = GNUNET_new (struct SYNC_DownloadOperation);
download->account_pub = *pub;
pub_str = GNUNET_STRINGS_data_to_string_alloc (pub,
sizeof (*pub));
GNUNET_asprintf (&download->url,
"%s%sbackups/%s",
base_url,
'/' == base_url[strlen (base_url) - 1]
? ""
: "/",
pub_str);
GNUNET_free (pub_str);
eh = SYNC_curl_easy_get_ (download->url);
GNUNET_assert (CURLE_OK ==
curl_easy_setopt (eh,
CURLOPT_HEADERFUNCTION,
&handle_header));
GNUNET_assert (CURLE_OK ==
curl_easy_setopt (eh,
CURLOPT_HEADERDATA,
download));
download->cb = cb;
download->cb_cls = cb_cls;
download->job = GNUNET_CURL_job_add_raw (ctx,
eh,
GNUNET_NO,
&handle_download_finished,
download);
return download;
}
/**
* Cancel the download.
*
* @param do operation to cancel.
*/
void
SYNC_download_cancel (struct SYNC_DownloadOperation *download)
{
if (NULL != download->job)
{
GNUNET_CURL_job_cancel (download->job);
download->job = NULL;
}
GNUNET_free (download->url);
GNUNET_free (download);
}
/* end of sync_api_download.c */