Finish crypto wrapping. Also provide wrappers for OpenSSL.

Disable libgcrypt by default. Since it doesn't support the OFB cipher mode,
we can't use it in a backwards compatible way.

src/gcrypt/digest.c

@@ -0,0 +1,140 @@
+/*
+    digest.c -- Digest handling
+    Copyright (C) 2007 Guus Sliepen <guus@tinc-vpn.org>
+
+    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 2 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, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+    $Id$
+*/
+
+#include "system.h"
+
+#include "digest.h"
+#include "logger.h"
+
+static struct {
+	const char *name;
+	int algo;
+	int nid;
+} digesttable[] = {
+	{"none", GCRY_MD_NONE, 0},
+	{"sha1", GCRY_MD_SHA1, 64},
+	{"sha256", GCRY_MD_SHA256, 672},
+	{"sha384", GCRY_MD_SHA384, 673},
+	{"sha512", GCRY_MD_SHA512, 674},
+};
+
+static bool nametodigest(const char *name, int *algo) {
+	int i;
+
+	for(i = 0; i < sizeof digesttable / sizeof *digesttable; i++) {
+		if(digesttable[i].name && !strcasecmp(name, digesttable[i].name)) {
+			*algo = digesttable[i].algo;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+static bool nidtodigest(int nid, int *algo) {
+	int i;
+
+	for(i = 0; i < sizeof digesttable / sizeof *digesttable; i++) {
+		if(nid == digesttable[i].nid) {
+			*algo = digesttable[i].algo;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+static bool digesttonid(int algo, int *nid) {
+	int i;
+
+	for(i = 0; i < sizeof digesttable / sizeof *digesttable; i++) {
+		if(algo == digesttable[i].algo) {
+			*nid = digesttable[i].nid;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+static bool digest_open(digest_t *digest, int algo) {
+	if(!digesttonid(algo, &digest->nid)) {
+		logger(LOG_DEBUG, _("Digest %d has no corresponding nid!"), algo);
+		return false;
+	}
+
+	digest->len = gcry_md_get_algo_dlen(algo);
+
+	return true;
+}
+
+bool digest_open_by_name(digest_t *digest, const char *name) {
+	int algo;
+
+	if(!nametodigest(name, &algo)) {
+		logger(LOG_DEBUG, _("Unknown digest name '%s'!"), name);
+		return false;
+	}
+
+	return digest_open(digest, algo);
+}
+
+bool digest_open_by_nid(digest_t *digest, int nid) {
+	int algo;
+
+	if(!nidtodigest(nid, &algo)) {
+		logger(LOG_DEBUG, _("Unknown digest ID %d!"), nid);
+		return false;
+	}
+
+	return digest_open(digest, algo);
+}
+
+bool digest_open_sha1(digest_t *digest) {
+	return digest_open(digest, GCRY_MD_SHA1);
+}
+
+void digest_close(digest_t *digest) {
+}
+
+bool digest_create(digest_t *digest, const void *indata, size_t inlen, void *outdata) {
+	gcry_md_hash_buffer(digest->algo, outdata, indata, inlen);
+	return true;
+}
+
+bool digest_verify(digest_t *digest, const void *indata, size_t inlen, const void *cmpdata) {
+	char outdata[digest->len];
+
+	gcry_md_hash_buffer(digest->algo, outdata, indata, inlen);
+	return !memcmp(cmpdata, outdata, digest->len);
+}
+
+int digest_get_nid(const digest_t *digest) {
+	return digest->nid;
+}
+
+size_t digest_length(const digest_t *digest) {
+	return digest->len;
+}
+
+bool digest_active(const digest_t *digest) {
+	return digest->algo != GCRY_MD_NONE;
+}