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authorDaniel Stenberg <daniel@haxx.se>2009-09-04 21:56:14 (GMT)
committerDaniel Stenberg <daniel@haxx.se>2009-09-04 21:56:14 (GMT)
commita5b204dd5b30eb9a9c3e7c88132e8e26b7400f10 (patch)
treedb6955f62d494bb0041b3a594fa95ce81a4bf001 /ares_parse_srv_reply.c
parentcef560e871533a197acfdc5106481105ef244194 (diff)
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- Jakub Hrozek added ares_parse_srv_reply() for SRV parsing
Diffstat (limited to 'ares_parse_srv_reply.c')
-rw-r--r--ares_parse_srv_reply.c159
1 files changed, 159 insertions, 0 deletions
diff --git a/ares_parse_srv_reply.c b/ares_parse_srv_reply.c
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+++ b/ares_parse_srv_reply.c
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+/* 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.
+ */
+
+/*
+ * ares_parse_srv_reply created by Jakub Hrozek <jhrozek@redhat.com>
+ * on behalf of Red Hat - http://www.redhat.com
+ */
+
+#include "setup.h"
+
+#if defined(WIN32) && !defined(WATT32)
+#include "nameser.h"
+#else
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <arpa/nameser.h>
+#ifdef HAVE_ARPA_NAMESER_COMPAT_H
+#include <arpa/nameser_compat.h>
+#endif
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#include "ares.h"
+#include "ares_dns.h"
+#include "ares_private.h"
+
+int
+ares_parse_srv_reply (const unsigned char *abuf, int alen,
+ struct srv_reply **srv_out, int *nsrvreply)
+{
+ 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 srv_reply *srv = NULL;
+
+ /* Set *srv_out to NULL for all failure cases. */
+ if (srv_out)
+ *srv_out = NULL;
+ /* Same with *nsrvreply. */
+ if (nsrvreply)
+ *nsrvreply = 0;
+
+ /* 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 srv_reply array; ancount gives an upper bound */
+ srv = malloc ((ancount) * sizeof (struct srv_reply));
+ if (!srv)
+ {
+ 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 SRV record */
+ if (rr_class == C_IN && rr_type == T_SRV)
+ {
+ /* parse the SRV record itself */
+ if (rr_len < 6)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
+
+ srv[i].priority = ntohs (*((uint16_t *)aptr));
+ aptr += sizeof(uint16_t);
+ srv[i].weight = ntohs (*((uint16_t *)aptr));
+ aptr += sizeof(uint16_t);
+ srv[i].port = ntohs (*((uint16_t *)aptr));
+ aptr += sizeof(uint16_t);
+
+ status = ares_expand_name (aptr, abuf, alen, &srv[i].host, &len);
+ if (status != ARES_SUCCESS)
+ break;
+
+ /* Move on to the next record */
+ aptr += len;
+
+ /* Don't lose memory in the next iteration */
+ free (rr_name);
+ rr_name = NULL;
+ }
+ }
+
+ /* clean up on error */
+ if (status != ARES_SUCCESS)
+ {
+ free (srv);
+ free (hostname);
+ free (rr_name);
+ return status;
+ }
+
+ /* everything looks fine, return the data */
+ *srv_out = srv;
+ *nsrvreply = ancount;
+
+ free (hostname);
+ free (rr_name);
+ return status;
+}