ares_parse_caa_reply - Parse a reply to a DNS query of type CAA
#include <ares.h> int ares_parse_caa_reply(const unsigned char* abuf, int alen, struct ares_caa_reply **caa_out);
ARES_PARSE_CAA_REPLY(3) Library Functions Manual ARES_PARSE_CAA_REPLY(3)
NAME
ares_parse_caa_reply - Parse a reply to a DNS query of type CAA
SYNOPSIS
#include <ares.h>
int ares_parse_caa_reply(const unsigned char* abuf, int alen,
struct ares_caa_reply **caa_out);
DESCRIPTION
The ares_parse_caa_reply function parses the response to a query of
type CAA into a linked list (one element per sub-string) of struct
ares_caa_reply The parameters abuf and 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 caa_out. It is the caller's
responsibility to free the resulting caa_out structure when it is no
longer needed using the function ares_free_data(3)
The structure ares_caa_reply(3) contains the following fields:
struct ares_caa_reply {
struct ares_caa_reply *next;
int critical;
unsigned char *property;
size_t plength; /* plength excludes null */
unsigned char *value;
size_t length; /* length excludes null */
};
RETURN VALUES
ares_parse_caa_reply can return any of the following values:
ARES_SUCCESS The response was successfully parsed.
ARES_EBADRESP The response was malformatted.
ARES_ENODATA The response did not contain an answer to the query.
ARES_ENOMEM Memory was exhausted.
EXAMPLE
#include <arpa/inet.h>
#include <time.h>
#include <sys/time.h>
#include <netdb.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include "ares.h"
static void dns_callback(void *arg,
int status,
int timeouts,
unsigned char *abuf,
int alen)
{
struct ares_caa_reply *caa_out;
int err;
err = ares_parse_caa_reply (abuf, alen, &caa_out);
if (err == ARES_SUCCESS)
{
struct ares_caa_reply *caa_curr;
for (caa_curr=caa_out; caa_curr; caa_curr=caa_curr->next)
printf ("%s. CAA %i %s \"%s\"\n", arg,
caa_curr->critical,
caa_curr->property,
caa_curr->value);
}
else
{
printf ("err=%i\n", err);
}
ares_free_data (caa_out);
}
static void main_loop(ares_channel *channel)
{
int nfds, count;
fd_set readers, writers;
struct timeval tv, *tvp;
while (1)
{
FD_ZERO (&readers);
FD_ZERO (&writers);
nfds = ares_fds (*channel, &readers, &writers);
if (nfds == 0)
break;
tvp = ares_timeout (*channel, NULL, &tv);
count = select (nfds, &readers, &writers, NULL, tvp);
ares_process (*channel, &readers, &writers);
}
}
int main(int argc, char **argv)
{
const char *sversion;
int iversion;
int err;
sversion = ares_version (&iversion);
printf ("c-ares version %s\n", sversion);
char *domain = "wikipedia.org";
if (argc > 1)
domain = argv[1];
ares_channel channel;
if ((err = ares_init (&channel)) != ARES_SUCCESS)
{
printf ("ares_init() failed (%i)\n", err);
exit (EXIT_FAILURE);
}
ares_query (channel, domain,
1, /* ns_c_in */
257, /* T_CAA */
dns_callback, domain);
main_loop (&channel);
ares_destroy (channel);
exit (EXIT_SUCCESS);
}
AVAILABILITY
This function was first introduced in c-ares version 1.17.0.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | library/libcares |
+---------------+------------------+
|Stability | Volatile |
+---------------+------------------+
SEE ALSO
ares_query(3) ares_free_data(3)
AUTHOR
Written by Danny Sonnenschein <my.card.god@web.de>, on behalf of
platynum, https://platynum.ch
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from https://c-ares.haxx.se/download/c-
ares-1.17.2.tar.gz.
Further information about this software can be found on the open source
community website at https://c-ares.haxx.se/.
16 September 2020 ARES_PARSE_CAA_REPLY(3)