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-rw-r--r--ares_parse_aaaa_reply.c173
1 files changed, 173 insertions, 0 deletions
diff --git a/ares_parse_aaaa_reply.c b/ares_parse_aaaa_reply.c
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+++ b/ares_parse_aaaa_reply.c
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+/* Copyright 2005 Dominick Meglio
+ *
+ * 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 "setup.h"
+#include <sys/types.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>
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#include "ares.h"
+#include "ares_dns.h"
+#include "ares_private.h"
+
+int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
+ struct hostent **host)
+{
+ unsigned int qdcount, ancount;
+ int status, i, rr_type, rr_class, rr_len, naddrs;
+ int naliases;
+ long len;
+ const unsigned char *aptr;
+ char *hostname, *rr_name, *rr_data, **aliases;
+ struct in6_addr *addrs;
+ struct hostent *hostent;
+
+ /* Set *host to NULL for all failure cases. */
+ *host = 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;
+
+ /* 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 addresses and aliases; ancount gives an upper bound for both. */
+ addrs = malloc(ancount * sizeof(struct in6_addr));
+ if (!addrs)
+ {
+ free(hostname);
+ return ARES_ENOMEM;
+ }
+ aliases = malloc((ancount + 1) * sizeof(char *));
+ if (!aliases)
+ {
+ free(hostname);
+ free(addrs);
+ return ARES_ENOMEM;
+ }
+ naddrs = 0;
+ naliases = 0;
+
+ /* 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;
+
+ if (rr_class == C_IN && rr_type == T_AAAA
+ && rr_len == sizeof(struct in6_addr)
+ && strcasecmp(rr_name, hostname) == 0)
+ {
+ memcpy(&addrs[naddrs], aptr, sizeof(struct in6_addr));
+ naddrs++;
+ status = ARES_SUCCESS;
+ }
+
+ if (rr_class == C_IN && rr_type == T_CNAME)
+ {
+ /* Record the RR name as an alias. */
+ aliases[naliases] = rr_name;
+ naliases++;
+
+ /* Decode the RR data and replace the hostname with it. */
+ status = ares_expand_name(aptr, abuf, alen, &rr_data, &len);
+ if (status != ARES_SUCCESS)
+ break;
+ free(hostname);
+ hostname = rr_data;
+ }
+ else
+ free(rr_name);
+
+ aptr += rr_len;
+ if (aptr > abuf + alen)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
+ }
+
+ if (status == ARES_SUCCESS && naddrs == 0)
+ status = ARES_ENODATA;
+ if (status == ARES_SUCCESS)
+ {
+ /* We got our answer. Allocate memory to build the host entry. */
+ aliases[naliases] = NULL;
+ hostent = malloc(sizeof(struct hostent));
+ if (hostent)
+ {
+ hostent->h_addr_list = malloc((naddrs + 1) * sizeof(char *));
+ if (hostent->h_addr_list)
+ {
+ /* Fill in the hostent and return successfully. */
+ hostent->h_name = hostname;
+ hostent->h_aliases = aliases;
+ hostent->h_addrtype = AF_INET6;
+ hostent->h_length = sizeof(struct in6_addr);
+ for (i = 0; i < naddrs; i++)
+ hostent->h_addr_list[i] = (char *) &addrs[i];
+ hostent->h_addr_list[naddrs] = NULL;
+ *host = hostent;
+ return ARES_SUCCESS;
+ }
+ free(hostent);
+ }
+ status = ARES_ENOMEM;
+ }
+ for (i = 0; i < naliases; i++)
+ free(aliases[i]);
+ free(aliases);
+ free(addrs);
+ free(hostname);
+ return status;
+}