You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

341 lines
12 KiB

/*
* Copyright (C) 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "chpp/clients/discovery.h"
#include <inttypes.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include "chpp/app.h"
#include "chpp/common/discovery.h"
#include "chpp/log.h"
#include "chpp/macros.h"
#include "chpp/memory.h"
#include "chpp/transport.h"
/************************************************
* Prototypes
***********************************************/
static inline bool chppIsClientCompatibleWithService(
const struct ChppClientDescriptor *client,
const struct ChppServiceDescriptor *service);
static uint8_t chppFindMatchingClient(
struct ChppAppState *context, const struct ChppServiceDescriptor *service);
static void chppDiscoveryProcessDiscoverAll(struct ChppAppState *context,
const uint8_t *buf, size_t len);
ChppNotifierFunction *chppGetClientMatchNotifierFunction(
struct ChppAppState *context, uint8_t index);
/************************************************
* Private Functions
***********************************************/
/**
* Determines if a client is compatible with a service. Compatibility
* requirements are:
* 1. UUIDs must match
* 2. Major version numbers must match
*
* @param client ChppClientDescriptor of client.
* @param service ChppServiceDescriptor of service.
*
* @param return True if compatible.
*/
static inline bool chppIsClientCompatibleWithService(
const struct ChppClientDescriptor *client,
const struct ChppServiceDescriptor *service) {
return (memcmp(client->uuid, service->uuid, CHPP_SERVICE_UUID_LEN) == 0 &&
client->version.major == service->version.major);
}
/**
* Attempts to match a registered client to a (discovered) service, responding
* with either the client index or CHPP_CLIENT_INDEX_NONE if it fails.
*
* @param context Maintains status for each app layer instance.
* @param service ChppServiceDescriptor of service.
*
* @param return Index of client matching the service, or CHPP_CLIENT_INDEX_NONE
* if there is none.
*/
static uint8_t chppFindMatchingClient(
struct ChppAppState *context, const struct ChppServiceDescriptor *service) {
uint8_t result = CHPP_CLIENT_INDEX_NONE;
for (uint8_t i = 0; i < context->registeredClientCount; i++) {
if (chppIsClientCompatibleWithService(
&context->registeredClients[i]->descriptor, service)) {
result = i;
break;
}
}
return result;
}
/**
* Processes the Discover All Services response
* (CHPP_DISCOVERY_COMMAND_DISCOVER_ALL).
*
* @param context Maintains status for each app layer instance.
* @param buf Input (request) datagram. Cannot be null.
* @param len Length of input data in bytes.
*/
static void chppDiscoveryProcessDiscoverAll(struct ChppAppState *context,
const uint8_t *buf, size_t len) {
if (context->isDiscoveryComplete) {
CHPP_LOGE("Duplicate discovery response");
return;
}
const struct ChppDiscoveryResponse *response =
(const struct ChppDiscoveryResponse *)buf;
size_t servicesLen = len - sizeof(struct ChppAppHeader);
uint8_t serviceCount =
(uint8_t)(servicesLen / sizeof(struct ChppServiceDescriptor));
if (servicesLen != serviceCount * sizeof(struct ChppServiceDescriptor)) {
// Incomplete service list
CHPP_LOGE("Descriptor len=%" PRIuSIZE " doesn't match count=%" PRIu8
" and size=%" PRIuSIZE,
servicesLen, serviceCount, sizeof(struct ChppServiceDescriptor));
CHPP_DEBUG_ASSERT(false);
}
if (serviceCount > CHPP_MAX_DISCOVERED_SERVICES) {
CHPP_LOGE("Service count=%" PRIu8 " larger than max=%d", serviceCount,
CHPP_MAX_DISCOVERED_SERVICES);
CHPP_DEBUG_ASSERT(false);
}
CHPP_LOGI("Discovered %" PRIu8 " services", serviceCount);
uint8_t matchedClients = 0;
for (uint8_t i = 0; i < MIN(serviceCount, CHPP_MAX_DISCOVERED_SERVICES);
i++) {
// Update lookup table
context->clientIndexOfServiceIndex[i] =
chppFindMatchingClient(context, &response->services[i]);
char uuidText[CHPP_SERVICE_UUID_STRING_LEN];
chppUuidToStr(response->services[i].uuid, uuidText);
if (context->clientIndexOfServiceIndex[i] == CHPP_CLIENT_INDEX_NONE) {
CHPP_LOGE(
"No matching client for service: %d"
" name=%s, UUID=%s, version=%" PRIu8 ".%" PRIu8 ".%" PRIu16,
CHPP_SERVICE_HANDLE_OF_INDEX(i), response->services[i].name, uuidText,
response->services[i].version.major,
response->services[i].version.minor,
response->services[i].version.patch);
} else {
CHPP_LOGD(
"Client # %" PRIu8
" matched to service on handle %d"
" with name=%s, UUID=%s. "
"client version=%" PRIu8 ".%" PRIu8 ".%" PRIu16
", service version=%" PRIu8 ".%" PRIu8 ".%" PRIu16,
context->clientIndexOfServiceIndex[i],
CHPP_SERVICE_HANDLE_OF_INDEX(i), response->services[i].name, uuidText,
context->registeredClients[context->clientIndexOfServiceIndex[i]]
->descriptor.version.major,
context->registeredClients[context->clientIndexOfServiceIndex[i]]
->descriptor.version.minor,
context->registeredClients[context->clientIndexOfServiceIndex[i]]
->descriptor.version.patch,
response->services[i].version.major,
response->services[i].version.minor,
response->services[i].version.patch);
// Initialize client
uint8_t idx = context->clientIndexOfServiceIndex[i];
if (context->registeredClients[idx]->initFunctionPtr(
context->registeredClientContexts[idx],
CHPP_SERVICE_HANDLE_OF_INDEX(i),
response->services[i].version) == false) {
CHPP_LOGE(
"Client rejected init: client ver=%" PRIu8 ".%" PRIu8 ".%" PRIu16
", service ver=%" PRIu8 ".%" PRIu8 ".%" PRIu16,
context->registeredClients[context->clientIndexOfServiceIndex[i]]
->descriptor.version.major,
context->registeredClients[context->clientIndexOfServiceIndex[i]]
->descriptor.version.minor,
context->registeredClients[context->clientIndexOfServiceIndex[i]]
->descriptor.version.patch,
response->services[i].version.major,
response->services[i].version.minor,
response->services[i].version.patch);
} else {
matchedClients++;
}
}
}
CHPP_LOGD("Matched %" PRIu8 " out of %" PRIu8 " clients and %" PRIu8
" services",
matchedClients, context->registeredClientCount, serviceCount);
// Notify any clients waiting on discovery completion
chppMutexLock(&context->discoveryMutex);
context->isDiscoveryComplete = true;
context->matchedClientCount = matchedClients;
context->discoveredServiceCount = serviceCount;
chppConditionVariableSignal(&context->discoveryCv);
chppMutexUnlock(&context->discoveryMutex);
// Notify clients of match
for (uint8_t i = 0; i < context->discoveredServiceCount; i++) {
uint8_t clientIndex = context->clientIndexOfServiceIndex[i];
if (clientIndex != CHPP_CLIENT_INDEX_NONE) {
// Discovered service has a matched client
ChppNotifierFunction *MatchNotifierFunction =
chppGetClientMatchNotifierFunction(context, clientIndex);
CHPP_LOGD("Client #%" PRIu8 " (H#%d) match notifier found=%d",
clientIndex, CHPP_SERVICE_HANDLE_OF_INDEX(i),
(MatchNotifierFunction != NULL));
if (MatchNotifierFunction != NULL) {
MatchNotifierFunction(context->registeredClientContexts[clientIndex]);
}
}
}
}
/**
* Returns the match notification function pointer of a particular negotiated
* client. The function pointer will be set to null by clients that do not need
* or support a match notification.
*
* @param context Maintains status for each app layer instance.
* @param index Index of the registered client.
*
* @return Pointer to the match notification function.
*/
ChppNotifierFunction *chppGetClientMatchNotifierFunction(
struct ChppAppState *context, uint8_t index) {
return context->registeredClients[index]->matchNotifierFunctionPtr;
}
/************************************************
* Public Functions
***********************************************/
void chppDiscoveryInit(struct ChppAppState *context) {
CHPP_ASSERT_LOG(!context->isDiscoveryClientInitialized,
"Discovery client already initialized");
CHPP_LOGD("Initializing CHPP discovery client");
if (!context->isDiscoveryClientInitialized) {
chppMutexInit(&context->discoveryMutex);
chppConditionVariableInit(&context->discoveryCv);
context->isDiscoveryClientInitialized = true;
}
context->matchedClientCount = 0;
context->isDiscoveryComplete = false;
context->isDiscoveryClientInitialized = true;
}
void chppDiscoveryDeinit(struct ChppAppState *context) {
CHPP_ASSERT_LOG(context->isDiscoveryClientInitialized,
"Discovery client already deinitialized");
CHPP_LOGD("Deinitializing CHPP discovery client");
context->isDiscoveryClientInitialized = false;
}
bool chppWaitForDiscoveryComplete(struct ChppAppState *context,
uint64_t timeoutMs) {
bool success = false;
if (!context->isDiscoveryClientInitialized) {
timeoutMs = 0;
} else {
success = true;
chppMutexLock(&context->discoveryMutex);
if (timeoutMs == 0) {
success = context->isDiscoveryComplete;
} else {
while (success && !context->isDiscoveryComplete) {
success = chppConditionVariableTimedWait(
&context->discoveryCv, &context->discoveryMutex,
timeoutMs * CHPP_NSEC_PER_MSEC);
}
}
chppMutexUnlock(&context->discoveryMutex);
}
if (!success) {
CHPP_LOGE("Discovery incomplete after %" PRIu64 " ms", timeoutMs);
}
return success;
}
bool chppDispatchDiscoveryServiceResponse(struct ChppAppState *context,
const uint8_t *buf, size_t len) {
const struct ChppAppHeader *rxHeader = (const struct ChppAppHeader *)buf;
bool success = true;
switch (rxHeader->command) {
case CHPP_DISCOVERY_COMMAND_DISCOVER_ALL: {
chppDiscoveryProcessDiscoverAll(context, buf, len);
break;
}
default: {
success = false;
break;
}
}
return success;
}
void chppInitiateDiscovery(struct ChppAppState *context) {
if (context->isDiscoveryComplete) {
CHPP_LOGE("Duplicate discovery init");
return;
}
for (uint8_t i = 0; i < CHPP_MAX_DISCOVERED_SERVICES; i++) {
context->clientIndexOfServiceIndex[i] = CHPP_CLIENT_INDEX_NONE;
}
struct ChppAppHeader *request = chppMalloc(sizeof(struct ChppAppHeader));
request->handle = CHPP_HANDLE_DISCOVERY;
request->type = CHPP_MESSAGE_TYPE_CLIENT_REQUEST;
request->transaction = 0;
request->error = CHPP_APP_ERROR_NONE;
request->command = CHPP_DISCOVERY_COMMAND_DISCOVER_ALL;
chppEnqueueTxDatagramOrFail(context->transportContext, request,
sizeof(*request));
}
bool chppAreAllClientsMatched(struct ChppAppState *context) {
bool success = false;
chppMutexLock(&context->discoveryMutex);
success = (context->isDiscoveryComplete) &&
(context->registeredClientCount == context->matchedClientCount);
chppMutexUnlock(&context->discoveryMutex);
return success;
}