SOA parser added

I need to do SOA queries, so here is a parser for them.

- ares_soa_reply: new struct
- ares_malloc_data/ares_free_soa: ARES_DATATYPE_SOA_REPLY
- ares_parse_soa_reply: actual function

1 files changed, 135 insertions, 0 deletions

diff --git a/ares_parse_soa_reply.c b/ares_parse_soa_reply.c
new file mode 100644
index 0000000..b811954
--- /dev/null
+++ b/ares_parse_soa_reply.c
@@ -0,0 +1,135 @@
+
+/* Copyright 1998 by the Massachusetts Institute of Technology.
+ * Copyright (C) 2012 Marko Kreen <markokr@gmail.com>
+ *
+ * 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 "ares_setup.h"
+
+#ifdef HAVE_SYS_SOCKET_H
+#  include <sys/socket.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#  include <netinet/in.h>
+#endif
+#ifdef HAVE_NETDB_H
+#  include <netdb.h>
+#endif
+#ifdef HAVE_ARPA_INET_H
+#  include <arpa/inet.h>
+#endif
+#ifdef HAVE_ARPA_NAMESER_H
+#  include <arpa/nameser.h>
+#else
+#  include "nameser.h"
+#endif
+#ifdef HAVE_ARPA_NAMESER_COMPAT_H
+#  include <arpa/nameser_compat.h>
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#include "ares.h"
+#include "ares_dns.h"
+#include "ares_data.h"
+#include "ares_private.h"
+
+int
+ares_parse_soa_reply(const unsigned char *abuf, int alen,
+		     struct ares_soa_reply **soa_out)
+{
+  const unsigned char *aptr;
+  long len;
+  char *qname = NULL, *rr_name = NULL;
+  struct ares_soa_reply *soa = NULL;
+  int qdcount, ancount;
+  int status;
+
+  if (alen < HFIXEDSZ)
+    return ARES_EBADRESP;
+
+  /* parse message header */
+  qdcount = DNS_HEADER_QDCOUNT(abuf);
+  ancount = DNS_HEADER_ANCOUNT(abuf);
+  if (qdcount != 1 || ancount != 1)
+    return ARES_EBADRESP;
+  aptr = abuf + HFIXEDSZ;
+
+  /* query name */
+  status = ares__expand_name_for_response(aptr, abuf, alen, &qname, &len);
+  if (status != ARES_SUCCESS)
+    goto failed_stat;
+  aptr += len;
+
+  /* skip qtype & qclass */
+  if (aptr + QFIXEDSZ > abuf + alen)
+    goto failed;
+  aptr += QFIXEDSZ;
+
+  /* rr_name */
+  status = ares__expand_name_for_response(aptr, abuf, alen, &rr_name, &len);
+  if (status != ARES_SUCCESS)
+    goto failed_stat;
+  aptr += len;
+
+  /* skip rr_type, rr_class, rr_ttl, rr_rdlen */
+  if (aptr + RRFIXEDSZ > abuf + alen)
+    goto failed;
+  aptr += RRFIXEDSZ;
+
+  /* allocate result struct */
+  soa = ares_malloc_data(ARES_DATATYPE_SOA_REPLY);
+  if (!soa)
+    return ARES_ENOMEM;
+
+  /* nsname */
+  status = ares__expand_name_for_response(aptr, abuf, alen, &soa->nsname, &len);
+  if (status != ARES_SUCCESS)
+    goto failed_stat;
+  aptr += len;
+
+  /* hostmaster */
+  status = ares__expand_name_for_response(aptr, abuf, alen, &soa->hostmaster, &len);
+  if (status != ARES_SUCCESS)
+    goto failed_stat;
+  aptr += len;
+
+  /* integer fields */
+  if (aptr + 5 * 4 > abuf + alen)
+    goto failed;
+  soa->serial = DNS__32BIT(aptr + 0 * 4);
+  soa->refresh = DNS__32BIT(aptr + 1 * 4);
+  soa->retry = DNS__32BIT(aptr + 2 * 4);
+  soa->expire = DNS__32BIT(aptr + 3 * 4);
+  soa->minttl = DNS__32BIT(aptr + 4 * 4);
+
+  free(qname);
+  free(rr_name);
+
+  *soa_out = soa;
+
+  return ARES_SUCCESS;
+
+failed:
+  status = ARES_EBADRESP;
+
+failed_stat:
+  ares_free_data(soa);
+  if (qname)
+    free(qname);
+  if (rr_name)
+    free(rr_name);
+  return status;
+}
+