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[mdns]: Support for querying subtypes #1028

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69 changes: 68 additions & 1 deletion components/mdns/include/mdns.h
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* SPDX-FileCopyrightText: 2015-2025 Espressif Systems (Shanghai) CO LTD
* SPDX-FileCopyrightText: 2015-2026 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
Expand Down Expand Up @@ -757,6 +757,47 @@ void mdns_query_results_free(mdns_result_t *results);
*/
esp_err_t mdns_query_ptr(const char *service_type, const char *proto, uint32_t timeout, size_t max_results, mdns_result_t **results);

/**
* @brief Query mDNS for service subtype (Selective Instance Enumeration per RFC 6763 Section 7.1)
*
* Sends a PTR query for `_subtype._sub._service_type._proto.local` to discover
* only the instances of a service that have the given subtype.
*
* @param service_type service type (_http, _arduino, _ftp etc.)
* @param proto service protocol (_tcp, _udp, etc.)
* @param subtype the subtype to query for (e.g. "_printer")
* @param timeout time in milliseconds to wait for answer.
* @param max_results maximum results to be collected
* @param results pointer to the results of the query
*
* @return
* - ESP_OK success
* - ESP_ERR_INVALID_STATE mDNS is not running
* - ESP_ERR_NO_MEM memory error
* - ESP_ERR_INVALID_ARG parameter error
*/
esp_err_t mdns_query_ptr_subtype(const char *service_type, const char *proto, const char *subtype,
uint32_t timeout, size_t max_results, mdns_result_t **results);

/**
* @brief Query mDNS for service subtype asynchronously (Selective Instance Enumeration per RFC 6763 Section 7.1)
*
* Sends a PTR query for `_subtype._sub._service_type._proto.local`.
* The search object must be checked for progress and deleted manually.
*
* @param service_type service type (_http, _arduino, _ftp etc.)
* @param proto service protocol (_tcp, _udp, etc.)
* @param subtype the subtype to query for (e.g. "_printer")
* @param timeout time in milliseconds during which mDNS query is active
* @param max_results maximum results to be collected
* @param notifier Notification function to be called when the result is ready, can be NULL
*
* @return mdns_search_once_s pointer to new search object if query initiated successfully.
* NULL otherwise.
*/
mdns_search_once_t *mdns_query_async_new_subtype(const char *service_type, const char *proto, const char *subtype,
uint32_t timeout, size_t max_results, mdns_query_notify_t notifier);

/**
* @brief Query mDNS for SRV record
*
Expand Down Expand Up @@ -919,6 +960,20 @@ esp_err_t mdns_netif_action(esp_netif_t *esp_netif, mdns_event_actions_t event_a
*/
mdns_browse_t *mdns_browse_new(const char *service, const char *proto, mdns_browse_notify_t notifier);

/**
* @brief Browse mDNS for a service subtype `_subtype._sub._service._proto`
* (Selective Instance Enumeration per RFC 6763 Section 7.1).
*
* @param service Pointer to the `_service` which will be browsed.
* @param proto Pointer to the `_proto` which will be browsed.
* @param subtype Pointer to the `_subtype` to restrict browsing to. Can be NULL for standard browse.
* @param notifier The callback which will be called when the browsing service changed.
* @return mdns_browse_t pointer to new browse object if initiated successfully.
* NULL otherwise.
*/
mdns_browse_t *mdns_browse_new_subtype(const char *service, const char *proto, const char *subtype,
mdns_browse_notify_t notifier);

/**
* @brief Stop the `_service._proto` browse.
* @param service Pointer to the `_service` which will be browsed.
Expand All @@ -930,6 +985,18 @@ mdns_browse_t *mdns_browse_new(const char *service, const char *proto, mdns_brow
*/
esp_err_t mdns_browse_delete(const char *service, const char *proto);

/**
* @brief Stop the `_subtype._sub._service._proto` browse.
* @param service Pointer to the `_service` which will be browsed.
* @param proto Pointer to the `_proto` which will be browsed.
* @param subtype Pointer to the `_subtype`. Can be NULL to match a browse without subtype.
* @return
* - ESP_OK success.
* - ESP_ERR_FAIL mDNS is not running or the browsing was never started.
* - ESP_ERR_NO_MEM memory error.
*/
esp_err_t mdns_browse_delete_subtype(const char *service, const char *proto, const char *subtype);

#ifdef __cplusplus
}
#endif
Expand Down
55 changes: 45 additions & 10 deletions components/mdns/mdns_browser.c
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* SPDX-FileCopyrightText: 2015-2025 Espressif Systems (Shanghai) CO LTD
* SPDX-FileCopyrightText: 2015-2026 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
Expand Down Expand Up @@ -50,6 +50,7 @@ static void browse_item_free(mdns_browse_t *browse)
{
mdns_mem_free(browse->service);
mdns_mem_free(browse->proto);
mdns_mem_free(browse->subtype);
if (browse->result) {
mdns_priv_query_results_free(browse->result);
}
Expand Down Expand Up @@ -79,12 +80,12 @@ static void browse_sync(mdns_browse_sync_t *browse_sync)
*/
static void browse_send(mdns_browse_t *browse, mdns_if_t interface)
{
// Using search once for sending the PTR query
mdns_search_once_t search = {0};

search.instance = NULL;
search.service = browse->service;
search.proto = browse->proto;
search.subtype = browse->subtype;
search.type = MDNS_TYPE_PTR;
search.unicast = false;
search.result = NULL;
Expand Down Expand Up @@ -113,6 +114,23 @@ void mdns_priv_browse_free(void)
}
}

static bool browse_match(const mdns_browse_t *a, const mdns_browse_t *b)
{
if (strlen(a->service) != strlen(b->service) || memcmp(a->service, b->service, strlen(a->service)) != 0) {
return false;
}
if (strlen(a->proto) != strlen(b->proto) || memcmp(a->proto, b->proto, strlen(a->proto)) != 0) {
return false;
}
if (a->subtype == NULL && b->subtype == NULL) {
return true;
}
if (a->subtype == NULL || b->subtype == NULL) {
return false;
}
return strlen(a->subtype) == strlen(b->subtype) && memcmp(a->subtype, b->subtype, strlen(a->subtype)) == 0;
}

/**
* @brief Mark browse as finished, remove and free it from browse chain
*/
Expand All @@ -122,8 +140,7 @@ static void browse_finish(mdns_browse_t *browse)
mdns_browse_t *b = s_browse;
mdns_browse_t *target_free = NULL;
while (b) {
if (strlen(b->service) == strlen(browse->service) && memcmp(b->service, browse->service, strlen(b->service)) == 0 &&
strlen(b->proto) == strlen(browse->proto) && memcmp(b->proto, browse->proto, strlen(b->proto)) == 0) {
if (browse_match(b, browse)) {
target_free = b;
b = b->next;
queueDetach(mdns_browse_t, s_browse, target_free);
Expand All @@ -138,7 +155,8 @@ static void browse_finish(mdns_browse_t *browse)
/**
* @brief Allocate new browse structure
*/
static mdns_browse_t *browse_init(const char *service, const char *proto, mdns_browse_notify_t notifier)
static mdns_browse_t *browse_init(const char *service, const char *proto, const char *subtype,
mdns_browse_notify_t notifier)
{
mdns_browse_t *browse = (mdns_browse_t *)mdns_mem_malloc(sizeof(mdns_browse_t));

Expand Down Expand Up @@ -166,6 +184,14 @@ static mdns_browse_t *browse_init(const char *service, const char *proto, mdns_b
}
}

if (!mdns_utils_str_null_or_empty(subtype)) {
browse->subtype = mdns_mem_strndup(subtype, MDNS_NAME_BUF_LEN - 1);
if (!browse->subtype) {
browse_item_free(browse);
return NULL;
}
}

browse->notifier = notifier;
return browse;
}
Expand All @@ -178,10 +204,8 @@ static void browse_add(mdns_browse_t *browse)
browse->state = BROWSE_RUNNING;
mdns_browse_t *queue = s_browse;
bool found = false;
// looking for this browse in active browses
while (queue) {
if (strlen(queue->service) == strlen(browse->service) && memcmp(queue->service, browse->service, strlen(queue->service)) == 0 &&
strlen(queue->proto) == strlen(browse->proto) && memcmp(queue->proto, browse->proto, strlen(queue->proto)) == 0) {
if (browse_match(queue, browse)) {
found = true;
break;
}
Expand Down Expand Up @@ -615,14 +639,20 @@ esp_err_t mdns_priv_browse_sync(mdns_browse_sync_t *browse_sync)
* @defgroup MDNS_PUBCLIC_API
*/
mdns_browse_t *mdns_browse_new(const char *service, const char *proto, mdns_browse_notify_t notifier)
{
return mdns_browse_new_subtype(service, proto, NULL, notifier);
}

mdns_browse_t *mdns_browse_new_subtype(const char *service, const char *proto, const char *subtype,
mdns_browse_notify_t notifier)
{
mdns_browse_t *browse = NULL;

if (!mdns_priv_is_server_init() || mdns_utils_str_null_or_empty(service) || mdns_utils_str_null_or_empty(proto)) {
return NULL;
}

browse = browse_init(service, proto, notifier);
browse = browse_init(service, proto, subtype, notifier);
if (!browse) {
return NULL;
}
Expand All @@ -636,14 +666,19 @@ mdns_browse_t *mdns_browse_new(const char *service, const char *proto, mdns_brow
}

esp_err_t mdns_browse_delete(const char *service, const char *proto)
{
return mdns_browse_delete_subtype(service, proto, NULL);
}

esp_err_t mdns_browse_delete_subtype(const char *service, const char *proto, const char *subtype)
{
mdns_browse_t *browse = NULL;

if (!mdns_priv_is_server_init() || mdns_utils_str_null_or_empty(service) || mdns_utils_str_null_or_empty(proto)) {
return ESP_FAIL;
}

browse = browse_init(service, proto, NULL);
browse = browse_init(service, proto, subtype, NULL);
if (!browse) {
return ESP_ERR_NO_MEM;
}
Expand Down
99 changes: 97 additions & 2 deletions components/mdns/mdns_querier.c
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* SPDX-FileCopyrightText: 2015-2025 Espressif Systems (Shanghai) CO LTD
* SPDX-FileCopyrightText: 2015-2026 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
Expand All @@ -21,6 +21,9 @@ static mdns_search_once_t *s_search_once;

static esp_err_t send_search_action(mdns_action_type_t type, mdns_search_once_t *search);
static void search_free(mdns_search_once_t *search);
static mdns_search_once_t *search_init_with_subtype(const char *name, const char *service, const char *proto,
const char *subtype, uint16_t type, bool unicast,
uint32_t timeout, uint8_t max_results, mdns_query_notify_t notifier);

void mdns_priv_query_results_free(mdns_result_t *results)
{
Expand Down Expand Up @@ -167,6 +170,7 @@ void mdns_priv_query_free(void)
mdns_mem_free(h->instance);
mdns_mem_free(h->service);
mdns_mem_free(h->proto);
mdns_mem_free(h->subtype);
vSemaphoreDelete(h->done_semaphore);
if (h->result) {
mdns_priv_query_results_free(h->result);
Expand Down Expand Up @@ -249,7 +253,15 @@ mdns_search_once_t *mdns_priv_query_find_from(mdns_search_once_t *s, mdns_name_t
}

if (type == MDNS_TYPE_PTR && type == s->type && !strcasecmp(name->service, s->service) && !strcasecmp(name->proto, s->proto)) {
return s;
if (name->sub) {
if (s->subtype && !strcasecmp(name->host, s->subtype)) {
return s;
}
} else if (!s->subtype) {
return s;
}
s = s->next;
continue;
}

s = s->next;
Expand Down Expand Up @@ -287,6 +299,7 @@ static mdns_tx_packet_t *create_search_packet(mdns_search_once_t *search, mdns_i
q->service = search->service;
q->proto = search->proto;
q->domain = MDNS_UTILS_DEFAULT_DOMAIN;
q->subtype = search->subtype;
q->own_dynamic_memory = false;
queueToEnd(mdns_out_question_t, packet->questions, q);

Expand Down Expand Up @@ -345,6 +358,7 @@ static void search_free(mdns_search_once_t *search)
mdns_mem_free(search->instance);
mdns_mem_free(search->service);
mdns_mem_free(search->proto);
mdns_mem_free(search->subtype);
vSemaphoreDelete(search->done_semaphore);
mdns_mem_free(search);
}
Expand All @@ -354,6 +368,13 @@ static void search_free(mdns_search_once_t *search)
*/
static mdns_search_once_t *search_init(const char *name, const char *service, const char *proto, uint16_t type, bool unicast,
uint32_t timeout, uint8_t max_results, mdns_query_notify_t notifier)
{
return search_init_with_subtype(name, service, proto, NULL, type, unicast, timeout, max_results, notifier);
}

static mdns_search_once_t *search_init_with_subtype(const char *name, const char *service, const char *proto,
const char *subtype, uint16_t type, bool unicast,
uint32_t timeout, uint8_t max_results, mdns_query_notify_t notifier)
{
mdns_search_once_t *search = (mdns_search_once_t *)mdns_mem_malloc(sizeof(mdns_search_once_t));
if (!search) {
Expand Down Expand Up @@ -392,6 +413,14 @@ static mdns_search_once_t *search_init(const char *name, const char *service, co
}
}

if (!mdns_utils_str_null_or_empty(subtype)) {
search->subtype = mdns_mem_strndup(subtype, MDNS_NAME_BUF_LEN - 1);
if (!search->subtype) {
search_free(search);
return NULL;
}
}

search->type = type;
search->unicast = unicast;
search->timeout = timeout;
Expand Down Expand Up @@ -775,6 +804,72 @@ esp_err_t mdns_query_ptr(const char *service, const char *proto, uint32_t timeou
return mdns_query(NULL, service, proto, MDNS_TYPE_PTR, timeout, max_results, results);
}

esp_err_t mdns_query_ptr_subtype(const char *service_type, const char *proto, const char *subtype,
uint32_t timeout, size_t max_results, mdns_result_t **results)
{
mdns_search_once_t *search = NULL;

if (mdns_utils_str_null_or_empty(service_type) || mdns_utils_str_null_or_empty(proto) ||
mdns_utils_str_null_or_empty(subtype)) {
return ESP_ERR_INVALID_ARG;
}

if (!results) {
return ESP_ERR_INVALID_ARG;
}

*results = NULL;

if (!mdns_priv_is_server_init()) {
return ESP_ERR_INVALID_STATE;
}

if (!timeout) {
return ESP_ERR_INVALID_ARG;
}

search = search_init_with_subtype(NULL, service_type, proto, subtype, MDNS_TYPE_PTR, false, timeout,
max_results, NULL);
if (!search) {
return ESP_ERR_NO_MEM;
}

if (send_search_action(ACTION_SEARCH_ADD, search)) {
search_free(search);
return ESP_ERR_NO_MEM;
}
xSemaphoreTake(search->done_semaphore, portMAX_DELAY);

*results = search->result;
search_free(search);

return ESP_OK;
}

mdns_search_once_t *mdns_query_async_new_subtype(const char *service_type, const char *proto, const char *subtype,
uint32_t timeout, size_t max_results, mdns_query_notify_t notifier)
{
mdns_search_once_t *search = NULL;

if (!mdns_priv_is_server_init() || !timeout || mdns_utils_str_null_or_empty(service_type) ||
mdns_utils_str_null_or_empty(proto) || mdns_utils_str_null_or_empty(subtype)) {
return NULL;
}

search = search_init_with_subtype(NULL, service_type, proto, subtype, MDNS_TYPE_PTR, false, timeout,
max_results, notifier);
if (!search) {
return NULL;
}

if (send_search_action(ACTION_SEARCH_ADD, search)) {
search_free(search);
return NULL;
}

return search;
}

esp_err_t mdns_query_srv(const char *instance, const char *service, const char *proto, uint32_t timeout, mdns_result_t **result)
{
if (mdns_utils_str_null_or_empty(instance) || mdns_utils_str_null_or_empty(service) || mdns_utils_str_null_or_empty(proto)) {
Expand Down
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