summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorSteinar H. Gunderson <sesse@google.com>2007-11-15 08:36:25 (GMT)
committerSteinar H. Gunderson <sesse@google.com>2007-11-15 08:36:25 (GMT)
commitb4bdb6d4d7915bf5e1a89b6ae19f7ffbcd2e8144 (patch)
treed1d94cb51374092ffc7f74e21eb342da707d7735
parent7cd35ce69858bb06a446ef7620ea52807d67d306 (diff)
downloadc-ares-b4bdb6d4d7915bf5e1a89b6ae19f7ffbcd2e8144.zip
c-ares-b4bdb6d4d7915bf5e1a89b6ae19f7ffbcd2e8144.tar.gz
c-ares-b4bdb6d4d7915bf5e1a89b6ae19f7ffbcd2e8144.tar.bz2
Return TTL data from ares_parse_{a,aaaa}_reply, if the user is so inclined. Patch from the Google tree.
-rw-r--r--ares.h23
-rw-r--r--ares_gethostbyname.c4
-rw-r--r--ares_parse_a_reply.321
-rw-r--r--ares_parse_a_reply.c134
-rw-r--r--ares_parse_aaaa_reply.321
-rw-r--r--ares_parse_aaaa_reply.c128
6 files changed, 253 insertions, 78 deletions
diff --git a/ares.h b/ares.h
index af7df70..5e34310 100644
--- a/ares.h
+++ b/ares.h
@@ -240,10 +240,29 @@ int ares_expand_name(const unsigned char *encoded, const unsigned char *abuf,
int alen, char **s, long *enclen);
int ares_expand_string(const unsigned char *encoded, const unsigned char *abuf,
int alen, unsigned char **s, long *enclen);
+
+struct addrttl {
+ struct in_addr ipaddr;
+ int ttl;
+};
+struct addr6ttl {
+ struct in6_addr ip6addr;
+ int ttl;
+};
+
+/*
+** Parse the buffer, starting at *abuf and of length alen bytes, previously
+** obtained from an ares_search call. Put the results in *host, if nonnull.
+** Also, if addrttls is nonnull, put up to *naddrttls IPv4 addresses along with
+** their TTLs in that array, and set *naddrttls to the number of addresses
+** so written.
+*/
int ares_parse_a_reply(const unsigned char *abuf, int alen,
- struct hostent **host);
+ struct hostent **host,
+ struct addrttl *addrttls, int *naddrttls);
int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
- struct hostent **host);
+ struct hostent **host,
+ struct addr6ttl *addrttls, int *naddrttls);
int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr,
int addrlen, int family, struct hostent **host);
int ares_parse_ns_reply(const unsigned char *abuf, int alen,
diff --git a/ares_gethostbyname.c b/ares_gethostbyname.c
index bdc8791..b96ac6b 100644
--- a/ares_gethostbyname.c
+++ b/ares_gethostbyname.c
@@ -160,13 +160,13 @@ static void host_callback(void *arg, int status, int timeouts,
{
if (hquery->family == AF_INET)
{
- status = ares_parse_a_reply(abuf, alen, &host);
+ status = ares_parse_a_reply(abuf, alen, &host, NULL, NULL);
if (host && channel->nsort)
sort_addresses(host, channel->sortlist, channel->nsort);
}
else if (hquery->family == AF_INET6)
{
- status = ares_parse_aaaa_reply(abuf, alen, &host);
+ status = ares_parse_aaaa_reply(abuf, alen, &host, NULL, NULL);
if (host && channel->nsort)
sort6_addresses(host, channel->sortlist, channel->nsort);
}
diff --git a/ares_parse_a_reply.3 b/ares_parse_a_reply.3
index 7acd70f..fff8e23 100644
--- a/ares_parse_a_reply.3
+++ b/ares_parse_a_reply.3
@@ -22,24 +22,39 @@ ares_parse_a_reply \- Parse a reply to a DNS query of type A into a hostent
.B #include <ares.h>
.PP
.B int ares_parse_a_reply(const unsigned char *\fIabuf\fP, int \fIalen\fP,
-.B struct hostent **\fIhost\fP);
+.B struct hostent **\fIhost\fP,
+.B struct addrttl *\fIaddrttls\fB, int *\fInaddrttls\fB);
.fi
.SH DESCRIPTION
The
.B ares_parse_a_reply
function parses the response to a query of type A into a
-.BR "struct hostent" .
+.BR "struct hostent"
+and/or an array of
+.BR "struct addrttls" .
The parameters
.I abuf
and
.I alen
give the contents of the response. The result is stored in allocated
memory and a pointer to it stored into the variable pointed to by
-.IR host .
+.IR host ,
+if host is nonnull.
It is the caller's responsibility to free the resulting host structure
using
.BR ares_free_hostent (3)
when it is no longer needed.
+.PP
+If
+.IR addrttls
+and
+.IR naddrttls
+are both nonnull,
+then up to *naddrttls
+.BR "struct addrttl"
+records are stored in the array pointed to by addrttls,
+and then *naddrttls is set to the number of records so stored.
+Note that the memory for these records is supplied by the caller.
.SH RETURN VALUES
.B ares_parse_a_reply
can return any of the following values:
diff --git a/ares_parse_a_reply.c b/ares_parse_a_reply.c
index 6f42750..4dea80e 100644
--- a/ares_parse_a_reply.c
+++ b/ares_parse_a_reply.c
@@ -37,19 +37,26 @@
#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)
@@ -73,20 +80,29 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen,
}
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;
@@ -106,13 +122,33 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen,
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));
+ 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;
}
@@ -120,7 +156,10 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen,
if (rr_class == C_IN && rr_type == T_CNAME)
{
/* Record the RR name as an alias. */
- aliases[naliases] = rr_name;
+ if (aliases)
+ aliases[naliases] = rr_name;
+ else
+ free(rr_name);
naliases++;
/* Decode the RR data and replace the hostname with it. */
@@ -129,6 +168,10 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen,
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);
@@ -145,32 +188,51 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen,
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)
+ /* We got our answer. */
+ if (naddrttls)
{
- hostent->h_addr_list = malloc((naddrs + 1) * sizeof(char *));
- if (hostent->h_addr_list)
+ const int n = naddrs < max_addr_ttls ? naddrs : max_addr_ttls;
+ for (i = 0; i < n; i++)
{
- /* 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;
+ /* Ensure that each A TTL is no larger than the CNAME TTL. */
+ if (addrttls[i].ttl > cname_ttl)
+ addrttls[i].ttl = cname_ttl;
}
- free(hostent);
+ *naddrttls = n;
}
- status = ARES_ENOMEM;
+ 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;
diff --git a/ares_parse_aaaa_reply.3 b/ares_parse_aaaa_reply.3
index 15ecd5e..3b80295 100644
--- a/ares_parse_aaaa_reply.3
+++ b/ares_parse_aaaa_reply.3
@@ -22,24 +22,39 @@ ares_parse_aaaa_reply \- Parse a reply to a DNS query of type AAAA into a hosten
.B #include <ares.h>
.PP
.B int ares_parse_aaaa_reply(const unsigned char *\fIabuf\fP, int \fIalen\fP,
-.B struct hostent **\fIhost\fP);
+.B struct hostent **\fIhost\fP,
+.B struct addrttl *\fIaddrttls\fB, int *\fInaddrttls\fB);
.fi
.SH DESCRIPTION
The
.B ares_parse_aaaa_reply
function parses the response to a query of type AAAA into a
-.BR "struct hostent" .
+.BR "struct hostent"
+and/or an array of
+.BR "struct addrttls" .
The parameters
.I abuf
and
.I alen
give the contents of the response. The result is stored in allocated
memory and a pointer to it stored into the variable pointed to by
-.IR host .
+.IR host ,
+if host is nonnull.
It is the caller's responsibility to free the resulting host structure
using
.BR ares_free_hostent (3)
when it is no longer needed.
+.PP
+If
+.IR addrttls
+and
+.IR naddrttls
+are both nonnull,
+then up to *naddrttls
+.BR "struct addr6ttl"
+records are stored in the array pointed to by addrttls,
+and then *naddrttls is set to the number of records so stored.
+Note that the memory for these records is supplied by the caller.
.SH RETURN VALUES
.B ares_parse_aaaa_reply
can return any of the following values:
diff --git a/ares_parse_aaaa_reply.c b/ares_parse_aaaa_reply.c
index 535d40e..3b578f1 100644
--- a/ares_parse_aaaa_reply.c
+++ b/ares_parse_aaaa_reply.c
@@ -40,19 +40,26 @@
#include "ares_private.h"
int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
- struct hostent **host)
+ struct hostent **host, struct addr6ttl *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 in6_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)
@@ -77,18 +84,26 @@ int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
aptr += len + QFIXEDSZ;
/* Allocate addresses and aliases; ancount gives an upper bound for both. */
- addrs = malloc(ancount * sizeof(struct in6_addr));
- if (!addrs)
+ if (host)
{
- free(hostname);
- return ARES_ENOMEM;
+ 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;
+ }
}
- aliases = malloc((ancount + 1) * sizeof(char *));
- if (!aliases)
+ else
{
- free(hostname);
- free(addrs);
- return ARES_ENOMEM;
+ addrs = NULL;
+ aliases = NULL;
}
naddrs = 0;
naliases = 0;
@@ -109,13 +124,33 @@ int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
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_AAAA
&& rr_len == sizeof(struct in6_addr)
&& strcasecmp(rr_name, hostname) == 0)
{
- memcpy(&addrs[naddrs], aptr, sizeof(struct in6_addr));
+ if (addrs)
+ {
+ if (aptr + sizeof(struct in6_addr) > abuf + alen)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
+ memcpy(&addrs[naddrs], aptr, sizeof(struct in6_addr));
+ }
+ if (naddrs < max_addr_ttls)
+ {
+ struct addr6ttl * const at = &addrttls[naddrs];
+ if (aptr + sizeof(struct in6_addr) > abuf + alen)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
+ memcpy(&at->ip6addr, aptr, sizeof(struct in6_addr));
+ at->ttl = rr_ttl;
+ }
naddrs++;
status = ARES_SUCCESS;
}
@@ -123,7 +158,10 @@ int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
if (rr_class == C_IN && rr_type == T_CNAME)
{
/* Record the RR name as an alias. */
- aliases[naliases] = rr_name;
+ if (aliases)
+ aliases[naliases] = rr_name;
+ else
+ free(rr_name);
naliases++;
/* Decode the RR data and replace the hostname with it. */
@@ -132,6 +170,10 @@ int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
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);
@@ -148,28 +190,50 @@ int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
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)
+ /* We got our answer. */
+ if (naddrttls)
{
- hostent->h_addr_list = malloc((naddrs + 1) * sizeof(char *));
- if (hostent->h_addr_list)
+ const int n = naddrs < max_addr_ttls ? naddrs : max_addr_ttls;
+ for (i = 0; i < n; i++)
{
- /* 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;
+ /* Ensure that each A TTL is no larger than the CNAME TTL. */
+ if (addrttls[i].ttl > cname_ttl)
+ addrttls[i].ttl = cname_ttl;
}
- free(hostent);
+ *naddrttls = n;
}
- status = ARES_ENOMEM;
+ 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_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;
+ }
+ }
+ if (aliases)
+ {
+ for (i = 0; i < naliases; i++)
+ free(aliases[i]);
+ free(aliases);
}
for (i = 0; i < naliases; i++)
free(aliases[i]);