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gcoap: split find-memo utility functions
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This splits the _find_req_memo util function into multiple variants that match on different things. This is done in preparation of a feature that has to find a request based on a token value, without creating an artificial pdu for that. A nice side effect is that it also makes the calls to the find functions a bit more readable by not relying on an anonymous bool input.
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@MichelRottleuthner
MichelRottleuthner committed Nov 15, 2023
1 parent 08af245 commit 50f21b9
Showing 1 changed file with 66 additions and 26 deletions.
92 changes: 66 additions & 26 deletions sys/net/application_layer/gcoap/gcoap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -68,8 +68,12 @@ static void _cease_retransmission(gcoap_request_memo_t *memo);
static size_t _handle_req(gcoap_socket_t *sock, coap_pkt_t *pdu, uint8_t *buf,
size_t len, sock_udp_ep_t *remote);
static void _expire_request(gcoap_request_memo_t *memo);
static void _find_req_memo(gcoap_request_memo_t **memo_ptr, coap_pkt_t *pdu,
const sock_udp_ep_t *remote, bool by_mid);
static gcoap_request_memo_t* _find_req_memo_by_mid(const sock_udp_ep_t *remote,
uint16_t mid);
static gcoap_request_memo_t* _find_req_memo_by_token(const sock_udp_ep_t *remote,
const uint8_t *token, size_t tkl);
static gcoap_request_memo_t* _find_req_memo_by_pdu_token(coap_pkt_t *src_pdu,
const sock_udp_ep_t *remote);
static int _find_resource(gcoap_socket_type_t tl_type,
coap_pkt_t *pdu,
const coap_resource_t **resource_ptr,
Expand Down Expand Up @@ -401,7 +405,7 @@ static void _process_coap_pdu(gcoap_socket_t *sock, sock_udp_ep_t *remote, sock_

if (coap_get_type(&pdu) == COAP_TYPE_RST) {
DEBUG("gcoap: received RST, expiring potentially existing memo\n");
_find_req_memo(&memo, &pdu, remote, true);
memo = _find_req_memo_by_mid(remote, pdu.hdr->id);
if (memo) {
event_timeout_clear(&memo->resp_evt_tmout);
_expire_request(memo);
Expand All @@ -419,7 +423,7 @@ static void _process_coap_pdu(gcoap_socket_t *sock, sock_udp_ep_t *remote, sock_
messagelayer_emptyresponse_type = COAP_TYPE_RST;
DEBUG("gcoap: Answering empty CON request with RST\n");
} else if (coap_get_type(&pdu) == COAP_TYPE_ACK) {
_find_req_memo(&memo, &pdu, remote, true);
memo = _find_req_memo_by_mid(remote, pdu.hdr->id);
if ((memo != NULL) && (memo->send_limit != GCOAP_SEND_LIMIT_NON)) {
DEBUG("gcoap: empty ACK processed, stopping retransmissions\n");
_cease_retransmission(memo);
Expand Down Expand Up @@ -460,7 +464,7 @@ static void _process_coap_pdu(gcoap_socket_t *sock, sock_udp_ep_t *remote, sock_
case COAP_CLASS_SUCCESS:
case COAP_CLASS_CLIENT_FAILURE:
case COAP_CLASS_SERVER_FAILURE:
_find_req_memo(&memo, &pdu, remote, false);
memo = _find_req_memo_by_pdu_token(&pdu, remote);
if (memo) {
switch (coap_get_type(&pdu)) {
case COAP_TYPE_CON:
Expand Down Expand Up @@ -860,46 +864,82 @@ static int _find_resource(gcoap_socket_type_t tl_type,
* Finds the memo for an outstanding request within the _coap_state.open_reqs
* array. Matches on remote endpoint and token.
*
* memo_ptr[out] -- Registered request memo, or NULL if not found
* src_pdu[in] -- PDU for token to match
* remote[in] -- Remote endpoint to match
* by_mid[in] -- true if matches are to be done based on Message ID, otherwise they are done by
* token
* remote[in] Remote endpoint to match
* token[in] Token to match
* tkl[in] Length of the token in bytes
*
* return Registered request memo, or NULL if not found
*/
static void _find_req_memo(gcoap_request_memo_t **memo_ptr, coap_pkt_t *src_pdu,
const sock_udp_ep_t *remote, bool by_mid)
static gcoap_request_memo_t* _find_req_memo_by_token(const sock_udp_ep_t *remote,
const uint8_t *token, size_t tkl)
{
*memo_ptr = NULL;
/* no need to initialize struct; we only care about buffer contents below */
coap_pkt_t memo_pdu_data;
coap_pkt_t *memo_pdu = &memo_pdu_data;
unsigned cmplen = coap_get_token_len(src_pdu);

for (int i = 0; i < CONFIG_GCOAP_REQ_WAITING_MAX; i++) {
if (_coap_state.open_reqs[i].state == GCOAP_MEMO_UNUSED) {
continue;
}

gcoap_request_memo_t *memo = &_coap_state.open_reqs[i];

memo_pdu->hdr = gcoap_request_memo_get_hdr(memo);
if (by_mid) {
if ((src_pdu->hdr->id == memo_pdu->hdr->id)
&& sock_udp_ep_equal(&memo->remote_ep, remote)) {
*memo_ptr = memo;
break;
}
} else if (coap_get_token_len(memo_pdu) == cmplen) {
if ((memcmp(coap_get_token(src_pdu), coap_get_token(memo_pdu), cmplen) == 0)

if (coap_get_token_len(memo_pdu) == tkl) {
if ((memcmp(token, coap_get_token(memo_pdu), tkl) == 0)
&& (sock_udp_ep_equal(&memo->remote_ep, remote)
/* Multicast addresses are not considered in matching responses */
|| sock_udp_ep_is_multicast(&memo->remote_ep)
)) {
*memo_ptr = memo;
break;
return memo;
}
}
}
return NULL;
}

/*
* Utility wrapper for _find_req_memo_by_token(), using the pdu token.
* Finds the memo for an outstanding request within the _coap_state.open_reqs
* array. Matches on remote endpoint and token of the pdu.
*
* src_pdu[in] PDU which holds the token for matching
* remote[in] Remote endpoint to match
*
* return Registered request memo, or NULL if not found
*/
static gcoap_request_memo_t* _find_req_memo_by_pdu_token(coap_pkt_t *src_pdu,
const sock_udp_ep_t *remote)
{
unsigned tkl = coap_get_token_len(src_pdu);
uint8_t *token = coap_get_token(src_pdu);
return _find_req_memo_by_token(remote, token, tkl);
}

/*
* Finds the memo for an outstanding request within the _coap_state.open_reqs
* array. Matches on remote endpoint and message ID.
*
* remote[in] Remote endpoint to match
* mid[in] Message ID to match
*
* return Registered request memo, or NULL if not found
*/
static gcoap_request_memo_t* _find_req_memo_by_mid(const sock_udp_ep_t *remote, uint16_t mid)
{
for (int i = 0; i < CONFIG_GCOAP_REQ_WAITING_MAX; i++) {
if (_coap_state.open_reqs[i].state == GCOAP_MEMO_UNUSED) {
continue;
}

gcoap_request_memo_t *memo = &_coap_state.open_reqs[i];

if ((mid == gcoap_request_memo_get_hdr(memo)->id) &&
sock_udp_ep_equal(&memo->remote_ep, remote)) {
return memo;
}
}
return NULL;
}

/* Calls handler callback on receipt of a timeout message. */
Expand Down Expand Up @@ -1818,7 +1858,7 @@ void gcoap_forward_proxy_find_req_memo(gcoap_request_memo_t **memo_ptr,
coap_pkt_t *src_pdu,
const sock_udp_ep_t *remote)
{
_find_req_memo(memo_ptr, src_pdu, remote, false);
*memo_ptr = _find_req_memo_by_pdu_token(src_pdu, remote);
}

void gcoap_forward_proxy_post_event(void *arg)
Expand Down

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