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authorAnas Nashif <anas.nashif@intel.com>2012-10-30 20:54:38 (GMT)
committerAnas Nashif <anas.nashif@intel.com>2012-10-30 20:54:38 (GMT)
commitb8e6c26b7b9608dffc84645f17fe4cf534af18dd (patch)
tree61d9fff2984aa043471a1c305cfc4c76d7a099fb /ares_parse_srv_reply.c
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Imported Upstream version 1.7.5upstream/1.7.5
Diffstat (limited to 'ares_parse_srv_reply.c')
-rw-r--r--ares_parse_srv_reply.c179
1 files changed, 179 insertions, 0 deletions
diff --git a/ares_parse_srv_reply.c b/ares_parse_srv_reply.c
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+
+/* Copyright 1998 by the Massachusetts Institute of Technology.
+ * Copyright (C) 2009 by Jakub Hrozek <jhrozek@redhat.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"
+
+/* AIX portability check */
+#ifndef T_SRV
+# define T_SRV 33 /* server selection */
+#endif
+
+int
+ares_parse_srv_reply (const unsigned char *abuf, int alen,
+ struct ares_srv_reply **srv_out)
+{
+ unsigned int qdcount, ancount, i;
+ const unsigned char *aptr, *vptr;
+ int status, rr_type, rr_class, rr_len;
+ long len;
+ char *hostname = NULL, *rr_name = NULL;
+ struct ares_srv_reply *srv_head = NULL;
+ struct ares_srv_reply *srv_last = NULL;
+ struct ares_srv_reply *srv_curr;
+
+ /* Set *srv_out to NULL for all failure cases. */
+ *srv_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;
+
+ /* Examine each answer resource record (RR) in turn. */
+ for (i = 0; i < 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;
+ }
+
+ /* Allocate storage for this SRV answer appending it to the list */
+ srv_curr = ares_malloc_data(ARES_DATATYPE_SRV_REPLY);
+ if (!srv_curr)
+ {
+ status = ARES_ENOMEM;
+ break;
+ }
+ if (srv_last)
+ {
+ srv_last->next = srv_curr;
+ }
+ else
+ {
+ srv_head = srv_curr;
+ }
+ srv_last = srv_curr;
+
+ vptr = aptr;
+ srv_curr->priority = DNS__16BIT(vptr);
+ vptr += sizeof(unsigned short);
+ srv_curr->weight = DNS__16BIT(vptr);
+ vptr += sizeof(unsigned short);
+ srv_curr->port = DNS__16BIT(vptr);
+ vptr += sizeof(unsigned short);
+
+ status = ares_expand_name (vptr, abuf, alen, &srv_curr->host, &len);
+ if (status != ARES_SUCCESS)
+ break;
+ }
+
+ /* Don't lose memory in the next iteration */
+ free (rr_name);
+ rr_name = NULL;
+
+ /* Move on to the next record */
+ aptr += rr_len;
+ }
+
+ if (hostname)
+ free (hostname);
+ if (rr_name)
+ free (rr_name);
+
+ /* clean up on error */
+ if (status != ARES_SUCCESS)
+ {
+ if (srv_head)
+ ares_free_data (srv_head);
+ return status;
+ }
+
+ /* everything looks fine, return the data */
+ *srv_out = srv_head;
+
+ return ARES_SUCCESS;
+}