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[common] Cleanup mDNS code, cache service records (#263)
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* Handle possible failure of mdns_resp_add_service

* One more place where mdns_resp_add_service may fail

* addServiceImpl should always store services

* Register in services when new netif is added

* Refactored handling of cached services.

---------

Co-authored-by: Kuba Szczodrzyński <[email protected]>
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@szupi-ipuzs @kuba2k2
szupi-ipuzs and kuba2k2 authored Sep 5, 2024
1 parent 41819f2 commit 31e1d51
Showing 1 changed file with 78 additions and 51 deletions.
129 changes: 78 additions & 51 deletions cores/common/arduino/libraries/common/mDNS/LwIPmDNS.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -20,38 +20,59 @@ extern "C" {

#if LWIP_MDNS_RESPONDER

static std::vector<char *> services_name;
static std::vector<char *> services;
static std::vector<uint8_t> protos;
static std::vector<uint16_t> ports;
static std::vector<std::vector<char *>> records;
struct CachedService {
CachedService(const char *_name, const char *_service, mdns_sd_proto _proto, uint16_t _port)
: name(strdup(_name)), service(strdup(_service)), proto(_proto), port(_port) {}

CachedService(const CachedService &) = delete;
CachedService &operator=(const CachedService &) = delete;

CachedService(CachedService &&other)
: name(other.name), service(other.service), proto(other.proto), port(other.port),
records(std::move(other.records)) {
other.name = nullptr;
other.service = nullptr;
other.records.clear();
}

~CachedService() {
if (name) {
free(name);
}

if (service) {
free(service);
}

for (auto &str : records) {
if (str) {
free(str);
}
}
}

char *name;
char *service;
mdns_sd_proto proto;
uint16_t port;
std::vector<char *> records;
};

static std::vector<CachedService> sCachedServices;

static const char *hostName;
#ifdef LWIP_NETIF_EXT_STATUS_CALLBACK
NETIF_DECLARE_EXT_CALLBACK(netif_callback)
#endif

static inline void freeAllocatedStrings(const std::vector<char *> &strings) {
for (auto &str : strings) {
free(str);
}
}

mDNS::mDNS() {}

mDNS::~mDNS() {
cleanup();
}

void mDNS::cleanup() {
freeAllocatedStrings(services_name);
services_name.clear();
freeAllocatedStrings(services);
services.clear();
for (auto &record : records) {
freeAllocatedStrings(record);
}
records.clear();
sCachedServices.clear();

free((void *)hostName);
hostName = NULL;
Expand All @@ -62,10 +83,10 @@ void mDNS::cleanup() {

static void mdnsTxtCallback(struct mdns_service *service, void *userdata) {
size_t index = (size_t)userdata;
if (index >= records.size())
if (index >= sCachedServices.size())
return;

for (const auto record : records[index]) {
for (const auto &record : sCachedServices[index].records) {
err_t err = mdns_resp_add_service_txtitem(service, record, strlen(record));
if (err != ERR_OK) {
LT_DM(MDNS, "Error %d while adding txt record: %s", err, record);
Expand All @@ -85,28 +106,33 @@ static void mdnsStatusCallback(struct netif *netif, uint8_t result, int8_t slot)

#ifdef LWIP_NETIF_EXT_STATUS_CALLBACK
static void addServices(struct netif *netif) {
for (uint8_t i = 0; i < services.size(); i++) {
for (uint8_t i = 0; i < sCachedServices.size(); i++) {
const auto &cachedService = sCachedServices[i];
LT_DM(
MDNS,
"Add service: netif %u / %s / %s / %u / %u",
netif->num,
services_name[i],
services[i],
protos[i],
ports[i]
cachedService.name,
cachedService.service,
cachedService.proto,
cachedService.port
);
mdns_resp_add_service(
s8_t slot = mdns_resp_add_service(
netif,
services_name[i],
services[i],
(mdns_sd_proto)protos[i],
ports[i],
cachedService.name,
cachedService.service,
cachedService.proto,
cachedService.port,
#if LWIP_VERSION_SIMPLE < 20200 // TTL removed in LwIP commit 62fb2fd749b (2.2.0 release)
255,
#endif
mdnsTxtCallback,
reinterpret_cast<void *>(i) // index of newly added service
);

if (slot < 0) {
LT_DM(MDNS, "mdns_resp_add_service returned error %d", slot);
}
}
}
#endif
Expand Down Expand Up @@ -145,9 +171,9 @@ mdns_netif_ext_status_callback(struct netif *netif, netif_nsc_reason_t reason, c
if (reason & LWIP_NSC_NETIF_REMOVED) {
LT_DM(MDNS, "Netif removed, stopping mDNS on netif %u", netif->num);
mdns_resp_remove_netif(netif);
} else if (reason & LWIP_NSC_STATUS_CHANGED) {
LT_DM(MDNS, "Netif changed, starting mDNS on netif %u", netif->num);
if (enableMDNS(netif) && services.size() > 0) {
} else if ((reason & LWIP_NSC_STATUS_CHANGED) || (reason & LWIP_NSC_NETIF_ADDED)) {
LT_DM(MDNS, "Netif changed/added, starting mDNS on netif %u", netif->num);
if (enableMDNS(netif) && sCachedServices.size() > 0) {
LT_DM(MDNS, "Adding services to netif %u", netif->num);
addServices(netif);
}
Expand Down Expand Up @@ -191,12 +217,17 @@ void mDNS::end() {
bool mDNS::addServiceImpl(const char *name, const char *service, uint8_t proto, uint16_t port) {
bool added = false;
struct netif *netif = netif_list;

std::size_t serviceIndex = sCachedServices.size();
// add the service to TXT record arrays
sCachedServices.emplace_back(name, service, (mdns_sd_proto)proto, port);

while (netif != NULL) {
if (netif_is_up(netif)) {
// register TXT callback;
// pass service index as userdata parameter
LT_DM(MDNS, "Add service: netif %u / %s / %s / %u / %u", netif->num, name, service, proto, port);
mdns_resp_add_service(
s8_t slot = mdns_resp_add_service(
netif,
name,
service,
Expand All @@ -206,38 +237,34 @@ bool mDNS::addServiceImpl(const char *name, const char *service, uint8_t proto,
255,
#endif
mdnsTxtCallback,
(void *)services.size() // index of newly added service
(void *)serviceIndex // index of newly added service
);

if (slot < 0) {
LT_DM(MDNS, "mdns_resp_add_service returned error %d", slot);
}

added = true;
}
netif = netif->next;
}

if (!added)
return false;

// add the service to TXT record arrays
services_name.push_back(strdup(name));
services.push_back(strdup(service));
protos.push_back(proto);
ports.push_back(port);
records.emplace_back();

return true;
return added;
}

bool mDNS::addServiceTxtImpl(const char *service, uint8_t proto, const char *item) {
uint8_t i;
for (i = 0; i < services.size(); i++) {
for (i = 0; i < sCachedServices.size(); i++) {
const auto &cachedService = sCachedServices[i];
// find a matching service
if (strcmp(services[i], service) == 0 && protos[i] == proto) {
if (strcmp(cachedService.service, service) == 0 && cachedService.proto == proto) {
break;
}
}
if (i == services.size())
if (i == sCachedServices.size())
return false;

records[i].push_back(strdup(item));
sCachedServices[i].records.push_back(strdup(item));
return true;
}

Expand Down

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