/**
* Runs the DNS-SD sequence to discover the sFlow server settings,
* collector addresses and ports and sampling rates and polling interval
* settings.
* The DNS query is scoped to query for entries in the domain (zone)
* configured as the domain override in the registry (if set), or the
* primary domain name configured on the system if there is no domain
* override.
* Note that the DNS query could fail or return no results if we are
* unable to discover the primary domain of the system.
* HSP *sp used to update the min TTL for DNS entries so that the
* next DNS request can be scheduled.
* HSPSFlowSettings *settings in which sFlow collector addresses and ports
* and sampling and polling settings will be populated.
* Returns the number of sFlow collectors discovered or -1 on failure.
*/
int dnsSD(HSP *sp, HSPSFlowSettings *settings)
{
char request[HSP_MAX_DNS_LEN];
if (sp->DNSSD_domain) {
sprintf_s(request, HSP_MAX_DNS_LEN, "%s%s", SFLOW_DNS_SD, sp->DNSSD_domain);
} else {
char domain[MAX_HOSTNAME_LEN];
memset(domain, 0, MAX_HOSTNAME_LEN);
DWORD len = MAX_HOSTNAME_LEN;
char *dot = "";
if (GetComputerNameEx(ComputerNameDnsDomain, domain, &len) == 0) {
DWORD err = GetLastError();
logErr(LOG_ERR, err, "dnsSD: cannot determined DNS domain for this computer error=%u", err);
} else if (len == 0) {
myLog(LOG_ERR, "dnsSD: DNS domain for this computer not set");
} else {
dot = ".";
}
sprintf_s(request, HSP_MAX_DNS_LEN, "%s%s%s", SFLOW_DNS_SD, dot, domain);
}
myLog(LOG_INFO, "dnsSD: request=%s", request);
int num_servers = dnsSD_Request(sp, settings, request, DNS_TYPE_SRV);
dnsSD_Request(sp, settings, request, DNS_TYPE_TEXT);
// it's ok even if only the SRV request succeeded
return num_servers; // -1 on error
}
int dnsSD(HSP *sp, HSPDnsCB callback)
{
int num_servers = dnsSD_Request(sp, SFLOW_DNS_SD, T_SRV, callback);
dnsSD_Request(sp, SFLOW_DNS_SD, T_TXT, callback);
// it's ok even if just the SRV request succeeded
return num_servers; // -1 on error
}
int dnsSD(HSP *sp, HSPDnsCB callback, HSPSFlowSettings *settings)
{
char request[HSP_MAX_DNS_LEN];
char *domain_override = sp->DNSSD_domain ? sp->DNSSD_domain : "";
snprintf(request, HSP_MAX_DNS_LEN, "%s%s", SFLOW_DNS_SD, domain_override);
int num_servers = dnsSD_Request(sp, request, T_SRV, callback, settings);
dnsSD_Request(sp, request, T_TXT, callback, settings);
// it's ok even if only the SRV request succeeded
return num_servers; // -1 on error
}
