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Return TTL data from ares_parse_{a,aaaa}_reply, if the user is so inclined. Patch from the Google tree.

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This commit is contained in:
Steinar H. Gunderson 2007-11-15 08:36:25 +00:00
parent 5c8b973d4f
commit 17fde12fb8
6 changed files with 253 additions and 78 deletions
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23
ares/ares.h
View File

@ -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,

4
ares/ares_gethostbyname.c
View File

@ -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);
}

21
ares/ares_parse_a_reply.3
View File

@ -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:

134
ares/ares_parse_a_reply.c
View File

@ -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;

21
ares/ares_parse_aaaa_reply.3
View File

@ -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:

128
ares/ares_parse_aaaa_reply.c
View File

@ -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]);