/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 *    Copyright 2014-2017 (c) Fraunhofer IOSB (Author: Julius Pfrommer)

 *    Copyright 2014-2016 (c) Sten Grüner

 *    Copyright 2014, 2017 (c) Florian Palm

 *    Copyright 2016 (c) Oleksiy Vasylyev

 *    Copyright 2016-2017 (c) Stefan Profanter, fortiss GmbH

 *    Copyright 2017 (c) frax2222

 *    Copyright 2017 (c) Mark Giraud, Fraunhofer IOSB

 *    Copyright 2026 (c) o6 Automation GmbH (Author: Andreas Ebner)

 */

#include "ua_server_internal.h"

#include "ua_discovery.h"

#include "ua_services.h"

#ifdef UA_ENABLE_DISCOVERY

#include <open62541/client.h>

static UA_StatusCode

setApplicationDescriptionFromRegisteredServer(const UA_FindServersRequest *request,

                                              UA_ApplicationDescription *target,

                                              const UA_RegisteredServer *rs) {

    UA_StatusCode retval =  UA_STATUSCODE_GOOD;

    target->applicationType = rs->serverType;

    retval |= UA_String_copy(&rs->serverUri, &target->applicationUri);

    retval |= UA_String_copy(&rs->productUri, &target->productUri);

    retval |= UA_String_copy(&rs->gatewayServerUri, &target->gatewayServerUri);

    if(retval != UA_STATUSCODE_GOOD)

        return retval;

    /* If the client requests a specific locale, select the corresponding server

     * name */

    if(request->localeIdsSize) {

        UA_Boolean appNameFound = false;

        for(size_t i = 0; i < request->localeIdsSize && !appNameFound; i++) {

            for(size_t j =0; j < rs->serverNamesSize; j++) {

                if(UA_String_equal(&request->localeIds[i],

                                   &rs->serverNames[j].locale)) {

                    retval = UA_LocalizedText_copy(&rs->serverNames[j],

                                                   &target->applicationName);

                    if(retval != UA_STATUSCODE_GOOD)

                        return retval;

                    appNameFound = true;

                    break;

                }

            }

        }

        /* Server does not have the requested local, therefore we can select the

         * most suitable one */

        if(!appNameFound && rs->serverNamesSize) {

            retval = UA_LocalizedText_copy(&rs->serverNames[0],

                                           &target->applicationName);

            if(retval != UA_STATUSCODE_GOOD)

                return retval;

        }

    } else if(rs->serverNamesSize) {

        /* Just take the first name */

        retval = UA_LocalizedText_copy(&rs->serverNames[0],

                                       &target->applicationName);

        if(retval != UA_STATUSCODE_GOOD)

            return retval;

    }

    /* TODO: Where do we get the discoveryProfileUri for application data? */

    if(rs->discoveryUrlsSize > 0) {

        target->discoveryUrls = (UA_String *)

            UA_calloc(rs->discoveryUrlsSize, sizeof(UA_String));

        if(!target->discoveryUrls)

            return UA_STATUSCODE_BADOUTOFMEMORY;

        target->discoveryUrlsSize = rs->discoveryUrlsSize;

        for(size_t i = 0; i < rs->discoveryUrlsSize; i++)

            retval |= UA_String_copy(&rs->discoveryUrls[i],

                                     &target->discoveryUrls[i]);

    }

    return retval;

}

#endif

UA_Boolean

Service_FindServers(UA_Server *server, UA_Session *session,

                    const UA_FindServersRequest *request,

                    UA_FindServersResponse *response) {

    UA_ServerConfig *sc = &server->config;

    UA_LOG_DEBUG_SESSION(sc->logging, session, "Processing FindServersRequest");

    UA_LOCK_ASSERT(&server->serviceMutex);

    /* Return the server itself? */

    UA_Boolean foundSelf = false;

    if(request->serverUrisSize) {

        for(size_t i = 0; i < request->serverUrisSize; i++) {

            if(UA_String_equal(&request->serverUris[i],

                               &sc->applicationDescription.applicationUri)) {

                foundSelf = true;

                break;

            }

        }

    } else {

        foundSelf = true;

    }

#ifndef UA_ENABLE_DISCOVERY

    if(!foundSelf)

        return true;

    response->responseHeader.serviceResult =

        UA_Array_copy(&sc->applicationDescription, 1, (void**)&response->servers,

                      &UA_TYPES[UA_TYPES_APPLICATIONDESCRIPTION]);

    if(response->responseHeader.serviceResult != UA_STATUSCODE_GOOD)

        return true;

    response->serversSize = 1;

#else

    UA_DiscoveryManager *dm = (UA_DiscoveryManager*)

        getServerComponentByName(server, UA_STRING("discovery"));

    if(!dm) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADINTERNALERROR;

        return true;

    }

    /* Allocate enough memory, including memory for the "self" response */

    size_t maxResults = dm->registeredServersSize + 1;

    response->servers = (UA_ApplicationDescription*)

        UA_Array_new(maxResults, &UA_TYPES[UA_TYPES_APPLICATIONDESCRIPTION]);

    if(!response->servers) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;

        return true;

    }

    size_t pos = 0;

    registeredServer *current;

    /* Copy "self" ApplicationDescriptions into the response */

    if(foundSelf) {

        response->responseHeader.serviceResult =

            UA_ApplicationDescription_copy(&sc->applicationDescription,

                                           &response->servers[pos]);

        pos++;

        if(response->responseHeader.serviceResult != UA_STATUSCODE_GOOD)

            goto cleanup;

    }

    /* Copy registered ApplicationDescriptions into the response */

    LIST_FOREACH(current, &dm->registeredServers, pointers) {

        UA_Boolean usable = (request->serverUrisSize == 0);

        if(!usable) {

            /* If client only requested a specific set of servers */

            for(size_t i = 0; i < request->serverUrisSize; i++) {

                if(UA_String_equal(&current->registeredServer.serverUri,

                                   &request->serverUris[i])) {

                    usable = true;

                    break;

                }

            }

        }

        if(!usable)

            continue;

        response->responseHeader.serviceResult |=

            setApplicationDescriptionFromRegisteredServer(request,

                                                          &response->servers[pos],

                                                          &current->registeredServer);

        pos++;

    }

 cleanup:

    /* Set the final size */

    if(pos == 0) {

        UA_free(response->servers);

        response->servers = NULL;

    }

    response->serversSize = pos;

#endif

    /* Mirror back the expected EndpointUrl */

    if(request->endpointUrl.length > 0) {

        for(size_t i = 0; i < response->serversSize; i++) {

            UA_ApplicationDescription *ad = &response->servers[i];

            UA_Array_delete(ad->discoveryUrls, ad->discoveryUrlsSize,

                            &UA_TYPES[UA_TYPES_STRING]);

            ad->discoveryUrls = NULL;

            ad->discoveryUrlsSize = 0;

            response->responseHeader.serviceResult =

                UA_Array_copy(&request->endpointUrl, 1,

                              (void**)&ad->discoveryUrls,

                              &UA_TYPES[UA_TYPES_STRING]);

            if(response->responseHeader.serviceResult != UA_STATUSCODE_GOOD)

                break;

            ad->discoveryUrlsSize = 1;

        }

    }

    return true;

}

#if defined(UA_ENABLE_DISCOVERY) && defined(UA_ENABLE_DISCOVERY_MULTICAST)

/* All filter criteria must be fulfilled in the list entry. The comparison is

 * case insensitive. Returns true if the entry matches the filter. */

static UA_Boolean

entryMatchesCapabilityFilter(size_t serverCapabilityFilterSize,

                             UA_String *serverCapabilityFilter,

                             UA_ServerOnNetwork *current) {

    /* If the entry has less capabilities defined than the filter, there's no match */

    if(serverCapabilityFilterSize > current->serverCapabilitiesSize)

        return false;

    for(size_t i = 0; i < serverCapabilityFilterSize; i++) {

        UA_Boolean capabilityFound = false;

        for(size_t j = 0; j < current->serverCapabilitiesSize; j++) {

            if(UA_String_equal_ignorecase(&serverCapabilityFilter[i],

                               &current->serverCapabilities[j])) {

                capabilityFound = true;

                break;

            }

        }

        if(!capabilityFound)

            return false;

    }

    return true;

}

UA_Boolean

Service_FindServersOnNetwork(UA_Server *server, UA_Session *session,

                             const UA_FindServersOnNetworkRequest *request,

                             UA_FindServersOnNetworkResponse *response) {

    UA_LOCK_ASSERT(&server->serviceMutex);

    UA_DiscoveryManager *dm = (UA_DiscoveryManager*)

        getServerComponentByName(server, UA_STRING("discovery"));

    if(!dm) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADINTERNALERROR;

        return true;

    }

    if(!server->config.mdnsEnabled) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADNOTIMPLEMENTED;

        return true;

    }

    /* Set LastCounterResetTime */

    response->lastCounterResetTime =

        UA_DiscoveryManager_getServerOnNetworkCounterResetTime(dm);

    /* Compute the max number of records to return */

    UA_UInt32 recordCount = 0;

    UA_UInt32 serverOnNetworkRecordIdCounter =

        UA_DiscoveryManager_getServerOnNetworkRecordIdCounter(dm);

    if(request->startingRecordId < serverOnNetworkRecordIdCounter)

        recordCount = serverOnNetworkRecordIdCounter - request->startingRecordId;

    if(request->maxRecordsToReturn && recordCount > request->maxRecordsToReturn)

        recordCount = UA_MIN(recordCount, request->maxRecordsToReturn);

    if(recordCount == 0) {

        response->serversSize = 0;

        return true;

    }

    /* Iterate over all records and add to filtered list */

    UA_UInt32 filteredCount = 0;

    UA_STACKARRAY(UA_ServerOnNetwork*, filtered, recordCount);

    UA_ServerOnNetwork *current = UA_DiscoveryManager_getServerOnNetworkList(dm);

    if(!current) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADINTERNALERROR;

        return true;

    }

    for(size_t i = 0; i < recordCount; i++) {

        if(filteredCount >= recordCount)

            break;

        if(current->recordId < request->startingRecordId)

            continue;

        if(!entryMatchesCapabilityFilter(request->serverCapabilityFilterSize,

                               request->serverCapabilityFilter, current))

            continue;

        filtered[filteredCount++] = current;

        current = UA_DiscoveryManager_getNextServerOnNetworkRecord(dm, current);

        if(!current)

            break;

    }

    if(filteredCount == 0)

        return true;

    /* Allocate the array for the response */

    response->servers = (UA_ServerOnNetwork*)

        UA_malloc(sizeof(UA_ServerOnNetwork)*filteredCount);

    if(!response->servers) {

        response->responseHeader.serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;

        return true;

    }

    response->serversSize = filteredCount;

    /* Copy the server names */

    for(size_t i = 0; i < filteredCount; i++) {

        UA_ServerOnNetwork_copy(filtered[i], &response->servers[filteredCount-i-1]);

    }

    return true;

}

#endif

static UA_String basic256Sha256Uri = UA_STRING_STATIC("http://opcfoundation.org/UA/SecurityPolicy#Basic256Sha256");

/* Get an encrypted policy or NULL if no encrypted policy is defined */

UA_SecurityPolicy *

getDefaultEncryptedSecurityPolicy(UA_Server *server,

                                  UA_SecurityPolicyType type) {

    UA_SecurityPolicy *best = NULL;

    UA_Byte securityLevel = 0;

    (void)type;

    for(size_t i = 0; i < server->config.securityPoliciesSize; i++) {

        UA_SecurityPolicy *sp = &server->config.securityPolicies[i];

        if(sp->policyType == UA_SECURITYPOLICYTYPE_NONE)

            continue;

        /* This SecurityPolicy is used to secure a UserIdentityToken on top of a

         * #None SecureChannel (the only situation this function is called for).

         * ECC and RSA-DH policies use ephemeral key agreement that must be

         * bound to a secured SecureChannel - they must never be used to secure

         * an auth token over #None. Only the static-RSA encryption policies

         * (e.g. Basic256Sha256, Aes*_RsaOaep/RsaPss) qualify. */

        if(UA_SecurityPolicy_isEcc(sp) || UA_SecurityPolicy_isEnhancedSecurity(sp))

            continue;

        /* Return early with Basic256Sha256 when available. "Secure enough" and

         * most clients support it.*/

        if(UA_String_equal(&basic256Sha256Uri, &sp->policyUri))

            return sp;

        if(sp->securityLevel >= securityLevel) {

            best = sp;

            securityLevel = sp->securityLevel;

        }

    }

    return best;

}

static const char *securityModeStrs[4] = {"-invalid", "-none", "-sign", "-sign+encrypt"};

UA_String

securityPolicyUriPostfix(const UA_String uri) {

    if(uri.length == 0) return uri;

    for(UA_Byte *b = uri.data + uri.length - 1; b >= uri.data; b--) {

        if(*b != '#')

            continue;

        UA_String postfix = {uri.length - (size_t)(b - uri.data), b};

        return postfix;

    }

    return uri;

}

static UA_StatusCode

updateEndpointUserIdentityToken(UA_Server *server,

                                UA_SecurityPolicyType policyType,

                                UA_EndpointDescription *ed) {

    /* Don't modify the UserIdentityTokens if there are manually configured

     * entries */

    if(ed->userIdentityTokensSize > 0)

        return UA_STATUSCODE_GOOD;

    /* Copy the UserTokenPolicies from the AccessControl plugin, but only the

     * matching ones to the securityPolicyUri.

     * TODO: Different instances of the AccessControl plugin per Endpoint */

    UA_StatusCode res = UA_STATUSCODE_GOOD;

    UA_ServerConfig *sc = &server->config;

    for(size_t i = 0; i < sc->accessControl.userTokenPoliciesSize; i++) {

        UA_UserTokenPolicy *utp = &sc->accessControl.userTokenPolicies[i];

        /* Append the UserTokenPolicy from the AccesssControl plugin */

        res = UA_Array_appendCopy((void**)&ed->userIdentityTokens,

                                  &ed->userIdentityTokensSize, utp,

                                  &UA_TYPES[UA_TYPES_USERTOKENPOLICY]);

        if(res != UA_STATUSCODE_GOOD)

            return res;

        /* Now we modify the freshly copied last entry and ignore whatever

         * SecurityPolicy was set in sc->accessControl.userTokenPolicies and

         * choose something appropriate. If empty, the SecurityPolicy of the

         * SecureChannel is used. */

        utp = &ed->userIdentityTokens[ed->userIdentityTokensSize - 1];

        UA_String_clear(&utp->securityPolicyUri);

#ifdef UA_ENABLE_ENCRYPTION

        /* Anonymous tokens don't need encryption. All other tokens require

         * encryption with the exception of Username/Password if also the

         * allowNonePolicyPassword option has been set. The same logic is used

         * in selectEndpointAndTokenPolicy (ua_services_session.c). */

        if(utp->tokenType != UA_USERTOKENTYPE_ANONYMOUS &&

           UA_String_equal(&ed->securityPolicyUri, &UA_SECURITY_POLICY_NONE_URI) &&

           (!sc->allowNonePolicyPassword || utp->tokenType != UA_USERTOKENTYPE_USERNAME)) {

            /* Use the SecurityPolicy for the SecureChannel also for the

             * username/password. Otherwise pick the "bëst" SecurityPolicÿ. */

            UA_SecurityPolicy *encSP;

            if(ed->securityMode == UA_MESSAGESECURITYMODE_NONE)

                encSP = getDefaultEncryptedSecurityPolicy(server, policyType);

            else

                encSP = getSecurityPolicyByUri(server, &ed->securityPolicyUri);

            if(!encSP) {

                /* No encrypted SecurityPolicy available */

                UA_LOG_WARNING(sc->logging, UA_LOGCATEGORY_CLIENT,

                               "Removing a UserTokenPolicy that would allow the "

                               "password to be transmitted without encryption "

                               "(Can be enabled via config->allowNonePolicyPassword)");

                UA_StatusCode res2 =

                    UA_Array_resize((void **)&ed->userIdentityTokens,

                                    &ed->userIdentityTokensSize,

                                    ed->userIdentityTokensSize - 1,

                                    &UA_TYPES[UA_TYPES_USERTOKENPOLICY]);

                (void)res2;

                continue;

            }

            res |= UA_String_copy(&encSP->policyUri, &utp->securityPolicyUri);

        }

#endif

        /* Append the SecurityMode and SecurityPolicy postfix to the PolicyId to

         * make it unique */

        UA_String postfix;

        if(utp->securityPolicyUri.length > 0)

            postfix = securityPolicyUriPostfix(utp->securityPolicyUri);

        else

            postfix = securityPolicyUriPostfix(ed->securityPolicyUri);

        size_t newLen = utp->policyId.length + postfix.length +

            strlen(securityModeStrs[ed->securityMode]);

        UA_Byte *newString = (UA_Byte*)UA_realloc(utp->policyId.data, newLen);

        if(!newString)

            continue;

        size_t pos = utp->policyId.length;

        memcpy(&newString[pos], securityModeStrs[ed->securityMode],

               strlen(securityModeStrs[ed->securityMode]));

        pos += strlen(securityModeStrs[ed->securityMode]);

        memcpy(&newString[pos], postfix.data, postfix.length);

        utp->policyId.data = newString;

        utp->policyId.length = newLen;

    }

    return res;

}

/* Also reused to create the EndpointDescription array in the

 * CreateSessionResponse */

UA_StatusCode

setCurrentEndpointsArray(UA_Server *server, const UA_String endpointUrl,

                         UA_String *profileUris, size_t profileUrisSize,

                         UA_EndpointDescription **arr, size_t *arrSize) {

    UA_ServerConfig *sc = &server->config;

    /* Clone the endpoint for each discoveryURL? */

    size_t clone_times = 1;

    if(endpointUrl.length == 0)

        clone_times = sc->applicationDescription.discoveryUrlsSize;

    /* Allocate the array */

    *arr = (UA_EndpointDescription*)

        UA_Array_new(sc->endpointsSize * clone_times,

                     &UA_TYPES[UA_TYPES_ENDPOINTDESCRIPTION]);

    if(!*arr)

        return UA_STATUSCODE_BADOUTOFMEMORY;

    size_t pos = 0;

    UA_StatusCode retval = UA_STATUSCODE_GOOD;

    for(size_t j = 0; j < sc->endpointsSize; ++j) {

        const UA_EndpointDescription *ep = &sc->endpoints[j];

        /* Test if the supported binary profile shall be returned */

        UA_Boolean usable = (profileUrisSize == 0);

        if(!usable) {

            for(size_t i = 0; i < profileUrisSize; ++i) {

                if(!UA_String_equal(&profileUris[i], &ep->transportProfileUri))

                    continue;

                usable = true;

                break;

            }

        }

        if(!usable)

            continue;

        /* Get the SecurityPolicy */

        UA_SecurityPolicy *sp =

            getSecurityPolicyByUri(server, &ep->securityPolicyUri);

        if(!sp) {

            UA_LOG_WARNING(server->config.logging, UA_LOGCATEGORY_SERVER,

                           "GetEndpoints: Endpoint defines SecurityPolicy "

                           "%S which is not available", ep->securityPolicyUri);

            continue;

        }

        /* Copy into the results */

        for(size_t i = 0; i < clone_times; ++i) {

            /* Copy the endpoint with a current ApplicationDescription */

            UA_EndpointDescription *ed = &(*arr)[pos];

            retval |= UA_EndpointDescription_copy(&sc->endpoints[j], ed);

            UA_ApplicationDescription_clear(&ed->server);

            retval |= UA_ApplicationDescription_copy(&sc->applicationDescription,

                                                     &ed->server);

            /* Set the local certificate configured for the SecurityPolicy */

            UA_ByteString_clear(&ed->serverCertificate);

            retval |= UA_ByteString_copy(&sp->localCertificate,

                                         &ed->serverCertificate);

            /* Set the User Identity Token list from the AccessControl plugin.

             * This also selects an appropriate SecurityPolicy for the

             * AuthenticationToken. */

            retval |= updateEndpointUserIdentityToken(server, sp->policyType, ed);

            /* OPC UA Part 4 §5.4.2:

             *

             * If the endpoint uses None security but a token policy requires

             * encryption, the client needs a certificate to encrypt the token.

             * Set serverCertificate from the first token policy's encryption

             * SecurityPolicy so the client can encrypt the credential. */

            if(ed->serverCertificate.length == 0) {

                for(size_t ti = 0; ti < ed->userIdentityTokensSize; ti++) {

                    UA_UserTokenPolicy *utp = &ed->userIdentityTokens[ti];

                    if(utp->securityPolicyUri.length == 0)

                        continue;

                    UA_SecurityPolicy *encSP =

                        getSecurityPolicyByUri(server, &utp->securityPolicyUri);

                    if(!encSP || encSP->localCertificate.length == 0)

                        continue;

                    retval |= UA_ByteString_copy(&encSP->localCertificate,

                                                 &ed->serverCertificate);

                    break;

                }

            }

            /* Set the EndpointURL */

            UA_String_clear(&ed->endpointUrl);

            if(endpointUrl.length == 0) {

                retval |= UA_String_copy(&sc->applicationDescription.discoveryUrls[i],

                                         &ed->endpointUrl);

            } else {

                /* Mirror back the requested EndpointUrl and also add it to the

                 * array of discovery urls */

                retval |= UA_String_copy(&endpointUrl, &ed->endpointUrl);

                /* Check if the ServerUrl is already present in the DiscoveryUrl

                 * array */

                size_t k = 0;

                for(; k < ed->server.discoveryUrlsSize; k++) {

                    if(UA_String_equal(&ed->endpointUrl, &ed->server.discoveryUrls[k]))

                        break;

                }

                if(k == ed->server.discoveryUrlsSize) {

                    retval |= UA_Array_appendCopy((void **)&ed->server.discoveryUrls,

                                                  &ed->server.discoveryUrlsSize,

                                                  &endpointUrl,

                                                  &UA_TYPES[UA_TYPES_STRING]);

                }

            }

            if(retval != UA_STATUSCODE_GOOD)

                goto error;

            pos++;

        }

    }

    *arrSize = pos;

    return UA_STATUSCODE_GOOD;

 error:

    UA_Array_delete(*arr, sc->endpointsSize * clone_times,

                    &UA_TYPES[UA_TYPES_ENDPOINTDESCRIPTION]);

    *arr = NULL;

    return retval;

}

UA_Boolean

Service_GetEndpoints(UA_Server *server, UA_Session *session,

                     const UA_GetEndpointsRequest *request,

                     UA_GetEndpointsResponse *response) {

    UA_LOCK_ASSERT(&server->serviceMutex);

    UA_LOG_DEBUG_SESSION(server->config.logging, session,

                         "Processing GetEndpointsRequest with endpointUrl %S",

                         request->endpointUrl);

    /* If the client expects to see a specific endpointurl, mirror it back. If

     * not, clone the endpoints with the discovery url of all networklayers. */

    response->responseHeader.serviceResult =

        setCurrentEndpointsArray(server, request->endpointUrl,

                                 request->profileUris, request->profileUrisSize,

                                 &response->endpoints, &response->endpointsSize);

    return true;

}

#ifdef UA_ENABLE_DISCOVERY

static void

process_RegisterServer(UA_Server *server, UA_Session *session,

                       const UA_RequestHeader* requestHeader,

                       const UA_RegisteredServer *requestServer,

                       const size_t requestDiscoveryConfigurationSize,

                       const UA_ExtensionObject *requestDiscoveryConfiguration,

                       UA_ResponseHeader* responseHeader,

                       size_t *responseConfigurationResultsSize,

                       UA_StatusCode **responseConfigurationResults,

                       size_t *responseDiagnosticInfosSize,

                       UA_DiagnosticInfo *responseDiagnosticInfos) {

    UA_LOCK_ASSERT(&server->serviceMutex);

    UA_DiscoveryManager *dm = (UA_DiscoveryManager*)

        getServerComponentByName(server, UA_STRING("discovery"));

    if(!dm)

        return;

    UA_ServerConfig *sc = &server->config;

    if(sc->applicationDescription.applicationType != UA_APPLICATIONTYPE_DISCOVERYSERVER) {

        responseHeader->serviceResult = UA_STATUSCODE_BADSERVICEUNSUPPORTED;

        return;

    }

    /* Find the server from the request in the registered list */

    registeredServer *rs = NULL;

    LIST_FOREACH(rs, &dm->registeredServers, pointers) {

        if(UA_String_equal(&rs->registeredServer.serverUri, &requestServer->serverUri))

            break;

    }

    UA_MdnsDiscoveryConfiguration *mdnsConfig = NULL;

    const UA_String* mdnsServerName = NULL;

    if(requestDiscoveryConfigurationSize) {

        *responseConfigurationResults =

            (UA_StatusCode *)UA_Array_new(requestDiscoveryConfigurationSize,

                                          &UA_TYPES[UA_TYPES_STATUSCODE]);

        if(!(*responseConfigurationResults)) {

            responseHeader->serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;

            return;

        }

        *responseConfigurationResultsSize = requestDiscoveryConfigurationSize;

        for(size_t i = 0; i < requestDiscoveryConfigurationSize; i++) {

            const UA_ExtensionObject *object = &requestDiscoveryConfiguration[i];

            if(!mdnsConfig && (object->encoding == UA_EXTENSIONOBJECT_DECODED ||

                               object->encoding == UA_EXTENSIONOBJECT_DECODED_NODELETE) &&

               (object->content.decoded.type == &UA_TYPES[UA_TYPES_MDNSDISCOVERYCONFIGURATION])) {

                mdnsConfig = (UA_MdnsDiscoveryConfiguration *)object->content.decoded.data;

                mdnsServerName = &mdnsConfig->mdnsServerName;

                (*responseConfigurationResults)[i] = UA_STATUSCODE_GOOD;

            } else {

                (*responseConfigurationResults)[i] = UA_STATUSCODE_BADNOTSUPPORTED;

            }

        }

    }

    if(!mdnsServerName && requestServer->serverNamesSize)

        mdnsServerName = &requestServer->serverNames[0].text;

    if(!mdnsServerName) {

        responseHeader->serviceResult = UA_STATUSCODE_BADSERVERNAMEMISSING;

        return;

    }

    if(requestServer->discoveryUrlsSize == 0) {

        responseHeader->serviceResult = UA_STATUSCODE_BADDISCOVERYURLMISSING;

        return;

    }

    if(requestServer->semaphoreFilePath.length) {

#ifdef UA_ENABLE_DISCOVERY_SEMAPHORE

        char* filePath = (char*)

            UA_malloc(sizeof(char)*requestServer->semaphoreFilePath.length+1);

        if(!filePath) {

            UA_LOG_ERROR_SESSION(sc->logging, session,

                                 "Cannot allocate memory for semaphore path. "

                                 "Out of memory.");

            responseHeader->serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;

            return;

        }

        memcpy(filePath, requestServer->semaphoreFilePath.data,

               requestServer->semaphoreFilePath.length );

        filePath[requestServer->semaphoreFilePath.length] = '\0';

        if(!UA_fileExists( filePath )) {

            responseHeader->serviceResult = UA_STATUSCODE_BADSEMAPHOREFILEMISSING;

            UA_free(filePath);

            return;

        }

        UA_free(filePath);

#else

        UA_LOG_WARNING(sc->logging, UA_LOGCATEGORY_CLIENT,

                       "Ignoring semaphore file path. open62541 not compiled "

                       "with UA_ENABLE_DISCOVERY_SEMAPHORE=ON");

#endif

    }

#ifdef UA_ENABLE_DISCOVERY_MULTICAST

    if(sc->mdnsEnabled) {

        for(size_t i = 0; i < requestServer->discoveryUrlsSize; i++) {

            /* create TXT if is online and first index, delete TXT if is offline

             * and last index */

            UA_Boolean updateTxt = (requestServer->isOnline && i==0) ||

                (!requestServer->isOnline && i==requestServer->discoveryUrlsSize);

            UA_Discovery_updateMdnsForDiscoveryUrl(dm, *mdnsServerName, mdnsConfig,

                                                   requestServer->discoveryUrls[i],

                                                   requestServer->isOnline, updateTxt);

        }

    }

#endif

    if(!requestServer->isOnline) {

        /* Server is shutting down. Remove it from the registered servers list */

        if(!rs) {

            /* Server not found, show warning */

            UA_LOG_WARNING_SESSION(sc->logging, session,

                                   "Could not unregister server %S. Not registered.",

                                   requestServer->serverUri);

            responseHeader->serviceResult = UA_STATUSCODE_BADNOTHINGTODO;

            return;

        }

        if(dm->registerServerCallback)

            dm->registerServerCallback(requestServer, dm->registerServerCallbackData);

        /* Server found, remove from list */

        LIST_REMOVE(rs, pointers);

        UA_RegisteredServer_clear(&rs->registeredServer);

        UA_free(rs);

        dm->registeredServersSize--;

        responseHeader->serviceResult = UA_STATUSCODE_GOOD;

        return;

    }

    UA_StatusCode retval = UA_STATUSCODE_GOOD;

    if(!rs) {

        /* Server not yet registered, register it by adding it to the list */

        UA_LOG_DEBUG_SESSION(sc->logging, session,

                             "Registering new server: %S",

                             requestServer->serverUri);

        rs = (registeredServer*)UA_malloc(sizeof(registeredServer));

        if(!rs) {

            responseHeader->serviceResult = UA_STATUSCODE_BADOUTOFMEMORY;

            return;

        }

        LIST_INSERT_HEAD(&dm->registeredServers, rs, pointers);

        dm->registeredServersSize++;

    } else {

        UA_RegisteredServer_clear(&rs->registeredServer);

    }

    /* Always call the callback, if it is set. Previously we only called it if

     * it was a new register call. It may be the case that this endpoint

     * registered before, then crashed, restarts and registeres again. In that

     * case the entry is not deleted and the callback would not be called. */

    if(dm->registerServerCallback)

        dm->registerServerCallback(requestServer,

                                   dm->registerServerCallbackData);

    /* Ccopy the data from the request into the list */

    UA_EventLoop *el = sc->eventLoop;

    UA_DateTime nowMonotonic = el->dateTime_nowMonotonic(el);

    UA_RegisteredServer_copy(requestServer, &rs->registeredServer);

    rs->lastSeen = nowMonotonic;

    responseHeader->serviceResult = retval;

}

UA_Boolean

Service_RegisterServer(UA_Server *server, UA_Session *session,

                       const UA_RegisterServerRequest *request,

                       UA_RegisterServerResponse *response) {

    UA_LOG_DEBUG_SESSION(server->config.logging, session,

                         "Processing RegisterServerRequest");

    UA_LOCK_ASSERT(&server->serviceMutex);

    process_RegisterServer(server, session, &request->requestHeader,

                           &request->server, 0, NULL, &response->responseHeader,

                           0, NULL, 0, NULL);

    return true;

}

UA_Boolean

Service_RegisterServer2(UA_Server *server, UA_Session *session,

                        const UA_RegisterServer2Request *request,

                        UA_RegisterServer2Response *response) {

    UA_LOG_DEBUG_SESSION(server->config.logging, session,

                         "Processing RegisterServer2Request");

    UA_LOCK_ASSERT(&server->serviceMutex);

    process_RegisterServer(server, session, &request->requestHeader,

                           &request->server,

                           request->discoveryConfigurationSize,

                           request->discoveryConfiguration,

                           &response->responseHeader,

                           &response->configurationResultsSize,

                           &response->configurationResults,

                           &response->diagnosticInfosSize,

                           response->diagnosticInfos);

    return true;

}

#endif /* UA_ENABLE_DISCOVERY */