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_re- ply 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 func- tion 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_t **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_t *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. SEE ALSO ares_query(3) ares_free_data(3) 16 September 2020 ARES_PARSE_CAA_REPLY(3)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | EXAMPLE | AVAILABILITY | SEE ALSO
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