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authorJakub Hrozek <jhrozek@redhat.com>2009-07-15 18:21:15 +0200
committerSimo Sorce <ssorce@redhat.com>2009-07-24 10:21:43 -0400
commitb6bf81803977318aad8b876a56a42e4a3ffbae6a (patch)
treeedc8117a07bce3e6cbe0a7ff5e2dd674afdcc2dc /server/resolv/ares/ares_parse_txt_reply.c
parentb919feeb115751ddda02a326e1d2636f1c83e32f (diff)
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Add ares helpers into sssd
This patch adds ares parsing functions that are not yet upstreamed together with a private ares header file (ares_dns.h) that contains some necessary macros for parsing common structures in the replies. Users of these two parsing functions must also include the header files ares_parse_{srv,txt}_reply.h that contain the function and structures declarations that should eventually end up in upstream ares.h
Diffstat (limited to 'server/resolv/ares/ares_parse_txt_reply.c')
-rw-r--r--server/resolv/ares/ares_parse_txt_reply.c157
1 files changed, 157 insertions, 0 deletions
diff --git a/server/resolv/ares/ares_parse_txt_reply.c b/server/resolv/ares/ares_parse_txt_reply.c
new file mode 100644
index 00000000..feb6af23
--- /dev/null
+++ b/server/resolv/ares/ares_parse_txt_reply.c
@@ -0,0 +1,157 @@
+/*
+ SSSD
+
+ Async resolver - TXT records parsing
+
+ Authors:
+ Jakub Hrozek <jhrozek@redhat.com>
+
+ Copyright (C) Red Hat, Inc 2009
+
+ 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/>.
+*/
+
+/*
+ * This code is based on other c-ares parsing licensed as follows:
+
+ * Copyright 1998 by the Massachusetts Institute of Technology.
+ *
+ * Permission to use, copy, modify, and distribute this
+ * software and its documentation for any purpose and without
+ * fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting
+ * documentation, and that the name of M.I.T. not be used in
+ * advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose. It is provided "as is"
+ * without express or implied warranty.
+ */
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <arpa/nameser.h>
+#include <stdlib.h>
+#include <string.h>
+#include "ares.h"
+/* this drags in some private macros c-ares uses */
+#include "ares_dns.h"
+
+#include "ares_parse_txt_reply.h"
+
+int _ares_parse_txt_reply(const unsigned char* abuf, int alen,
+ struct txt_reply **txt_out, int *ntxtreply)
+{
+ unsigned int qdcount, ancount;
+ const unsigned char *aptr;
+ int status, i, rr_type, rr_class, rr_len;
+ long len;
+ char *hostname = NULL, *rr_name = NULL;
+ struct txt_reply *txt = NULL;
+
+ if (txt_out)
+ *txt_out = NULL;
+
+ /* Give up if abuf doesn't have room for a header. */
+ if (alen < HFIXEDSZ)
+ return ARES_EBADRESP;
+
+ /* Fetch the question and answer count from the header. */
+ qdcount = DNS_HEADER_QDCOUNT(abuf);
+ ancount = DNS_HEADER_ANCOUNT(abuf);
+ if (qdcount != 1)
+ return ARES_EBADRESP;
+ if (ancount == 0)
+ return ARES_ENODATA;
+
+ /* Expand the name from the question, and skip past the question. */
+ aptr = abuf + HFIXEDSZ;
+ status = ares_expand_name(aptr, abuf, alen, &hostname, &len);
+ if (status != ARES_SUCCESS)
+ return status;
+
+ if (aptr + len + QFIXEDSZ > abuf + alen)
+ {
+ free (hostname);
+ return ARES_EBADRESP;
+ }
+ aptr += len + QFIXEDSZ;
+
+ /* Allocate txt_reply array; ancount gives an upper bound */
+ txt = malloc ((ancount) * sizeof (struct txt_reply));
+ if (!txt)
+ {
+ free (hostname);
+ return ARES_ENOMEM;
+ }
+
+ /* Examine each answer resource record (RR) in turn. */
+ for (i = 0; i < (int) ancount; i++)
+ {
+ /* Decode the RR up to the data field. */
+ status = ares_expand_name(aptr, abuf, alen, &rr_name, &len);
+ if (status != ARES_SUCCESS)
+ {
+ break;
+ }
+ aptr += len;
+ if (aptr + RRFIXEDSZ > abuf + alen)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
+ rr_type = DNS_RR_TYPE(aptr);
+ rr_class = DNS_RR_CLASS(aptr);
+ rr_len = DNS_RR_LEN(aptr);
+ aptr += RRFIXEDSZ;
+
+ /* Check if we are really looking at a TXT record */
+ if (rr_class == C_IN && rr_type == T_TXT)
+ {
+ /* Grab the TXT payload */
+ txt[i].length = rr_len;
+ txt[i].txt = malloc(sizeof(unsigned char) * rr_len);
+ if (txt[i].txt == NULL)
+ {
+ status = ARES_ENOMEM;
+ break;
+ }
+ memcpy((void *) txt[i].txt, aptr+1, sizeof(unsigned char) * rr_len);
+ /* Move on to the next record */
+ aptr += rr_len;
+ }
+
+ /* Don't lose memory in the next iteration */
+ free(rr_name);
+ rr_name = NULL;
+ }
+
+ free(hostname);
+ free(rr_name);
+
+ /* clean up on error */
+ if (status != ARES_SUCCESS)
+ {
+ free (txt);
+ return status;
+ }
+
+ /* everything looks fine, return the data */
+ *txt_out = txt;
+ *ntxtreply = ancount;
+ return 0;
+}