+/* $Id$ */
+
/* Copyright 1998 by the Massachusetts Institute of Technology.
*
* Permission to use, copy, modify, and distribute this
*/
#include "setup.h"
-#include <sys/types.h>
-#ifdef WIN32
+#if defined(WIN32) && !defined(WATT32)
#include "nameser.h"
#else
#include <sys/socket.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
+#ifdef HAVE_STRINGS_H
+#include <strings.h>
#endif
#include <stdlib.h>
#include <string.h>
+#include <limits.h>
#include "ares.h"
#include "ares_dns.h"
#include "ares_private.h"
int ares_parse_a_reply(const unsigned char *abuf, int alen,
- struct hostent **host)
+ struct hostent **host,
+ struct addrttl *addrttls, int *naddrttls)
{
unsigned int qdcount, ancount;
- int status, i, rr_type, rr_class, rr_len, naddrs;
+ int status, i, rr_type, rr_class, rr_len, rr_ttl, naddrs;
+ int cname_ttl = INT_MAX; /* the TTL imposed by the CNAME chain */
int naliases;
long len;
const unsigned char *aptr;
char *hostname, *rr_name, *rr_data, **aliases;
struct in_addr *addrs;
struct hostent *hostent;
+ const int max_addr_ttls = (addrttls && naddrttls) ? *naddrttls : 0;
/* Set *host to NULL for all failure cases. */
- *host = NULL;
+ if (host)
+ *host = NULL;
+ /* Same with *naddrttls. */
+ if (naddrttls)
+ *naddrttls = 0;
/* Give up if abuf doesn't have room for a header. */
if (alen < HFIXEDSZ)
}
aptr += len + QFIXEDSZ;
- /* Allocate addresses and aliases; ancount gives an upper bound for both. */
- addrs = malloc(ancount * sizeof(struct in_addr));
- if (!addrs)
+ if (host)
{
- free(hostname);
- return ARES_ENOMEM;
+ /* Allocate addresses and aliases; ancount gives an upper bound for both. */
+ addrs = malloc(ancount * sizeof(struct in_addr));
+ if (!addrs)
+ {
+ free(hostname);
+ return ARES_ENOMEM;
+ }
+ aliases = malloc((ancount + 1) * sizeof(char *));
+ if (!aliases)
+ {
+ free(hostname);
+ free(addrs);
+ return ARES_ENOMEM;
+ }
}
- aliases = malloc((ancount + 1) * sizeof(char *));
- if (!aliases)
+ else
{
- free(hostname);
- free(addrs);
- return ARES_ENOMEM;
+ addrs = NULL;
+ aliases = NULL;
}
+
naddrs = 0;
naliases = 0;
/* Decode the RR up to the data field. */
status = ares_expand_name(aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
- break;
+ break;
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen)
- {
- status = ARES_EBADRESP;
- break;
- }
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
rr_type = DNS_RR_TYPE(aptr);
rr_class = DNS_RR_CLASS(aptr);
rr_len = DNS_RR_LEN(aptr);
+ rr_ttl = DNS_RR_TTL(aptr);
aptr += RRFIXEDSZ;
if (rr_class == C_IN && rr_type == T_A
- && rr_len == sizeof(struct in_addr)
- && strcasecmp(rr_name, hostname) == 0)
- {
- memcpy(&addrs[naddrs], aptr, sizeof(struct in_addr));
- naddrs++;
- status = ARES_SUCCESS;
- }
+ && rr_len == sizeof(struct in_addr)
+ && strcasecmp(rr_name, hostname) == 0)
+ {
+ if (addrs)
+ {
+ if (aptr + sizeof(struct in_addr) > abuf + alen)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
+ memcpy(&addrs[naddrs], aptr, sizeof(struct in_addr));
+ }
+ if (naddrs < max_addr_ttls)
+ {
+ struct addrttl * const at = &addrttls[naddrs];
+ if (aptr + sizeof(struct in_addr) > abuf + alen)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
+ memcpy(&at->ipaddr, aptr, sizeof(struct in_addr));
+ at->ttl = rr_ttl;
+ }
+ 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;
- }
+ {
+ /* Record the RR name as an alias. */
+ if (aliases)
+ aliases[naliases] = rr_name;
+ else
+ free(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;
+
+ /* Take the min of the TTLs we see in the CNAME chain. */
+ if (cname_ttl > rr_ttl)
+ cname_ttl = rr_ttl;
+ }
else
- free(rr_name);
+ free(rr_name);
aptr += rr_len;
if (aptr > abuf + alen)
- {
- status = ARES_EBADRESP;
- break;
- }
+ {
+ 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_INET;
- hostent->h_length = sizeof(struct in_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;
+ /* We got our answer. */
+ if (naddrttls)
+ {
+ const int n = naddrs < max_addr_ttls ? naddrs : max_addr_ttls;
+ for (i = 0; i < n; i++)
+ {
+ /* Ensure that each A TTL is no larger than the CNAME TTL. */
+ if (addrttls[i].ttl > cname_ttl)
+ addrttls[i].ttl = cname_ttl;
+ }
+ *naddrttls = n;
+ }
+ if (aliases)
+ aliases[naliases] = NULL;
+ if (host)
+ {
+ /* Allocate memory to build the host entry. */
+ 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_INET;
+ hostent->h_length = sizeof(struct in_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;
+ }
+ }
+ if (aliases)
+ {
+ for (i = 0; i < naliases; i++)
+ free(aliases[i]);
+ free(aliases);
}
- for (i = 0; i < naliases; i++)
- free(aliases[i]);
- free(aliases);
free(addrs);
free(hostname);
return status;
projects / platform / upstream / c-ares.git / blobdiff