I have a NCS v2.0.0 OpenThread CoAP server running on a nRF52840 set up as a MTD SED (2s data poll) that seems to not be able to respond to CoAP requests. I can send the request from a Linux system running ot-daemon using ot-cli and aiocoap for Python, both give the same results. Basically the CoAP message is received, however, there seems to be no attempt at sending a response and with verbose low level logging enabled, I also see no attempts or warnings/errors.
As an experiment, I overrode the response peer address with the multicast address (as opposed to the Linux system's IP Address from the request), and the response was sent. So this seems like an issue with the CoAP implementation? Or perhaps a settings issue? Here are the logs showing the nRF52840 receiving and "attempting" (at the application level) to send a response (you can see the second retransmit from the client side):
[00:00:10.834,472] <inf> net_openthread: [I] Mac-----------: Sent data poll, fp:yes [00:00:10.862,030] <inf> net_openthread: [I] MeshForwarder-: Received IPv6 UDP msg, len:84, chksum:e3c1, ecn:no, from:0xd000, sec:yes, prio:normal, rss:-56.0 [00:00:10.862,335] <inf> net_openthread: [I] MeshForwarder-: src:[2601:40b:c200:44e0:225:caff:fe48:d83b]:45150 [00:00:10.862,640] <inf> net_openthread: [I] MeshForwarder-: dst:[fdca:27f4:d1ed:a0fe:61b1:b45c:6807:1f25]:5683 [00:00:10.862,792] <inf> command_server: diagnostic [00:00:10.865,356] <inf> battery: Battery voltage: 2963V [00:00:10.866,485] <inf> command: Sending response (MID 59527) to coap://[2601:40b:c200:44e0:225:caff:fe48:d83b]:45150 [00:00:10.866,516] <inf> command: Payload [00:00:12.833,740] <inf> net_openthread: [I] Mac-----------: Sent data poll, fp:no [00:00:14.834,838] <inf> net_openthread: [I] Mac-----------: Sent data poll, fp:yes [00:00:14.861,968] <inf> net_openthread: [I] MeshForwarder-: Received IPv6 UDP msg, len:84, chksum:e3c1, ecn:no, from:0xd000, sec:yes, prio:normal, rss:-53.0 [00:00:14.862,274] <inf> net_openthread: [I] MeshForwarder-: src:[2601:40b:c200:44e0:225:caff:fe48:d83b]:45150 [00:00:14.862,579] <inf> net_openthread: [I] MeshForwarder-: dst:[fdca:27f4:d1ed:a0fe:61b1:b45c:6807:1f25]:5683 [00:00:16.834,320] <inf> net_openthread: [I] Mac-----------: Sent data poll, fp:no [00:00:18.833,282] <inf> net_openthread: [I] Mac-----------: Sent data poll, fp:no
Here is a good attempt when I override the peer IP address with the multicast address:
[00:00:10.878,540] <inf> net_openthread: [I] MeshForwarder-: Received IPv6 UDP msg, len:84, chksum:4f33, ecn:no, from:0x0c00, sec:yes, prio:normal, rss:-38.0 [00:00:10.878,845] <inf> net_openthread: [I] MeshForwarder-: src:[2601:40b:c200:44e0:225:caff:fe48:d83b]:46874 [00:00:10.879,150] <inf> net_openthread: [I] MeshForwarder-: dst:[fdca:27f4:d1ed:a0fe:61b1:b45c:6807:1f25]:5683 [00:00:10.879,302] <inf> command_server: diagnostic [00:00:10.881,866] <inf> battery: Battery voltage: 2959V [00:00:10.882,843] <inf> command: Sending response (MID 53988) to coap://[ff03:0:0:0:0:0:0:2]:46874 [00:00:10.882,873] <inf> command: Payload [00:00:10.901,092] <inf> net_openthread: [I] MeshForwarder-: Sent IPv6 HopOpts msg, len:257, chksum:0000, ecn:no, to:0x0c00, sec:yes, prio:normal [00:00:10.901,397] <inf> net_openthread: [I] MeshForwarder-: src:[fdca:27f4:d1ed:a0fe:61b1:b45c:6807:1f25] [00:00:10.901,672] <inf> net_openthread: [I] MeshForwarder-: dst:[ff03:0:0:0:0:0:0:2]
Config:
# Network CONFIG_NETWORKING=y CONFIG_NET_L2_OPENTHREAD=y CONFIG_NET_UDP_CHECKSUM=y # OpenThread CONFIG_OPENTHREAD_THREAD_VERSION_1_2=y CONFIG_OPENTHREAD_MANUAL_START=y CONFIG_OPENTHREAD_MTD=y CONFIG_OPENTHREAD_MTD_SED=y CONFIG_OPENTHREAD_JOINER=y CONFIG_OPENTHREAD_COAP=y CONFIG_OPENTHREAD_COAP_BLOCK=y CONFIG_OPENTHREAD_DEBUG=y CONFIG_OPENTHREAD_LOG_LEVEL_INFO=y CONFIG_OPENTHREAD_L2_DEBUG=y
Send response function:
otError xCommandResponseSend(otMessage *pxRequestMessage, const otMessageInfo *pxMessageInfo, uint8_t *pucData, uint16_t usLength)
{
otError xErr = OT_ERROR_NONE;
bool bBlock = false;
uint64_t ullBlockValue = 0;
otMessage *pxResponseMessage = NULL;
otCoapCode xResponseCode = OT_COAP_CODE_EMPTY;
BlockInfo_t xBlockInfo = {.pucData = pucData, .usLength = usLength};
if (pucData == NULL && usLength > 0)
{
xErr = OT_ERROR_INVALID_ARGS;
}
if (otCoapMessageGetCode(pxRequestMessage) == OT_COAP_CODE_GET)
{
otCoapOptionIterator xIterator;
xErr = otCoapOptionIteratorInit(&xIterator, pxRequestMessage);
if (otCoapOptionIteratorGetFirstOptionMatching(&xIterator, OT_COAP_OPTION_BLOCK2) != NULL)
{
xErr = otCoapOptionIteratorGetOptionUintValue(&xIterator, &ullBlockValue);
bBlock = true;
}
}
if (xErr == OT_ERROR_NONE)
{
if (otCoapMessageGetType(pxRequestMessage) == OT_COAP_TYPE_CONFIRMABLE || otCoapMessageGetCode(pxRequestMessage) == OT_COAP_CODE_GET)
{
if (otCoapMessageGetCode(pxRequestMessage) == OT_COAP_CODE_GET)
{
xResponseCode = OT_COAP_CODE_CONTENT;
}
else
{
xResponseCode = OT_COAP_CODE_VALID;
}
pxResponseMessage = otCoapNewMessage(openthread_get_default_instance(), NULL);
if (pxResponseMessage == NULL)
{
xErr = OT_ERROR_NO_BUFS;
}
}
}
if (xErr == OT_ERROR_NONE)
{
pxResponseMessage = otCoapNewMessage(openthread_get_default_instance(), NULL);
if (pxResponseMessage == NULL)
{
xErr = OT_ERROR_NO_BUFS;
}
}
if (xErr == OT_ERROR_NONE)
{
xErr = otCoapMessageInitResponse(pxResponseMessage, pxRequestMessage, OT_COAP_TYPE_ACKNOWLEDGMENT, xResponseCode);
}
if (xErr == OT_ERROR_NONE && xResponseCode == OT_COAP_CODE_CONTENT)
{
if (bBlock == true)
{
xErr = otCoapMessageAppendBlock2Option(pxResponseMessage, (uint32_t)(ullBlockValue >> 4), true, (otCoapBlockSzx)(ullBlockValue & 0x7));
if (xErr == OT_ERROR_NONE)
{
xErr = otCoapMessageSetPayloadMarker(pxResponseMessage);
}
}
else
{
xErr = otCoapMessageSetPayloadMarker(pxResponseMessage);
if (xErr == OT_ERROR_NONE)
{
xErr = otMessageAppend(pxResponseMessage, pucData, usLength);
}
}
}
if (xErr == OT_ERROR_NONE)
{
if (bBlock == true)
{
xErr = otCoapSendResponseBlockWise(openthread_get_default_instance(), pxResponseMessage, pxMessageInfo, &xBlockInfo, prvBlockwiseTxHook);
}
else
{
xErr = otCoapSendResponse(openthread_get_default_instance(), pxResponseMessage, pxMessageInfo);
}
}
if (xErr != OT_ERROR_NONE && pxResponseMessage != NULL)
{
otMessageFree(pxResponseMessage);
}
if (xErr != OT_ERROR_NONE)
{
LOG_ERR("%s -> Unable to send CoAP response: %s (%d)", __FUNCTION__, otThreadErrorToString(xErr), xErr);
}
else
{
char cPeerAddr[OT_IP6_SOCK_ADDR_STRING_SIZE];
otIp6AddressToString(&pxMessageInfo->mPeerAddr, cPeerAddr, OT_IP6_SOCK_ADDR_STRING_SIZE);
LOG_INF("Sending response (MID %d) to coap://[%s]:%d", otCoapMessageGetMessageId(pxRequestMessage), cPeerAddr, pxMessageInfo->mPeerPort);
}
return xErr;
}
