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examples/gcoap: split client and server implementation
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Move client and server side implementations into separate files to
increase readability. Also get rid of a goto.
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@maribu
maribu committed Jan 4, 2022
1 parent 3c5c351 commit 8002c87
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Showing 8 changed files with 290 additions and 170 deletions.
180 changes: 15 additions & 165 deletions examples/gcoap/gcoap_cli.c → examples/gcoap/client.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,92 +23,32 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "fmt.h"
#include "net/gcoap.h"
#include "net/utils.h"
#include "od.h"
#include "fmt.h"

#include "gcoap_example.h"

#define ENABLE_DEBUG 0
#include "debug.h"

#if IS_USED(MODULE_GCOAP_DTLS)
#include "net/credman.h"
#include "net/dsm.h"
#include "tinydtls_keys.h"

/* Example credential tag for credman. Tag together with the credential type needs to be unique. */
#define GCOAP_DTLS_CREDENTIAL_TAG 10

static const uint8_t psk_id_0[] = PSK_DEFAULT_IDENTITY;
static const uint8_t psk_key_0[] = PSK_DEFAULT_KEY;
static const credman_credential_t credential = {
.type = CREDMAN_TYPE_PSK,
.tag = GCOAP_DTLS_CREDENTIAL_TAG,
.params = {
.psk = {
.key = { .s = psk_key_0, .len = sizeof(psk_key_0) - 1, },
.id = { .s = psk_id_0, .len = sizeof(psk_id_0) - 1, },
}
},
};
#endif

static bool _proxied = false;
static sock_udp_ep_t _proxy_remote;
static char proxy_uri[64];

static ssize_t _encode_link(const coap_resource_t *resource, char *buf,
size_t maxlen, coap_link_encoder_ctx_t *context);
static void _resp_handler(const gcoap_request_memo_t *memo, coap_pkt_t* pdu,
const sock_udp_ep_t *remote);
static ssize_t _stats_handler(coap_pkt_t* pdu, uint8_t *buf, size_t len, void *ctx);
static ssize_t _riot_board_handler(coap_pkt_t* pdu, uint8_t *buf, size_t len, void *ctx);

/* CoAP resources. Must be sorted by path (ASCII order). */
static const coap_resource_t _resources[] = {
{ "/cli/stats", COAP_GET | COAP_PUT, _stats_handler, NULL },
{ "/riot/board", COAP_GET, _riot_board_handler, NULL },
};

static const char *_link_params[] = {
";ct=0;rt=\"count\";obs",
NULL
};

static gcoap_listener_t _listener = {
&_resources[0],
ARRAY_SIZE(_resources),
_encode_link,
NULL,
NULL
};

/* Retain request path to re-request if response includes block. User must not
* start a new request (with a new path) until any blockwise transfer
* completes or times out. */
#define _LAST_REQ_PATH_MAX (64)
static char _last_req_path[_LAST_REQ_PATH_MAX];

/* Counts requests sent by CLI. */
static uint16_t req_count = 0;

/* Adds link format params to resource list */
static ssize_t _encode_link(const coap_resource_t *resource, char *buf,
size_t maxlen, coap_link_encoder_ctx_t *context) {
ssize_t res = gcoap_encode_link(resource, buf, maxlen, context);
if (res > 0) {
if (_link_params[context->link_pos]
&& (strlen(_link_params[context->link_pos]) < (maxlen - res))) {
if (buf) {
memcpy(buf+res, _link_params[context->link_pos],
strlen(_link_params[context->link_pos]));
}
return res + strlen(_link_params[context->link_pos]);
}
}

return res;
}
uint16_t req_count = 0;

/*
* Response callback.
Expand Down Expand Up @@ -201,66 +141,6 @@ static void _resp_handler(const gcoap_request_memo_t *memo, coap_pkt_t* pdu,
}
}

/*
* Server callback for /cli/stats. Accepts either a GET or a PUT.
*
* GET: Returns the count of packets sent by the CLI.
* PUT: Updates the count of packets. Rejects an obviously bad request, but
* allows any two byte value for example purposes. Semantically, the only
* valid action is to set the value to 0.
*/
static ssize_t _stats_handler(coap_pkt_t* pdu, uint8_t *buf, size_t len, void *ctx)
{
(void)ctx;

/* read coap method type in packet */
unsigned method_flag = coap_method2flag(coap_get_code_detail(pdu));

switch (method_flag) {
case COAP_GET:
gcoap_resp_init(pdu, buf, len, COAP_CODE_CONTENT);
coap_opt_add_format(pdu, COAP_FORMAT_TEXT);
size_t resp_len = coap_opt_finish(pdu, COAP_OPT_FINISH_PAYLOAD);

/* write the response buffer with the request count value */
resp_len += fmt_u16_dec((char *)pdu->payload, req_count);
return resp_len;

case COAP_PUT:
/* convert the payload to an integer and update the internal
value */
if (pdu->payload_len <= 5) {
char payload[6] = { 0 };
memcpy(payload, (char *)pdu->payload, pdu->payload_len);
req_count = (uint16_t)strtoul(payload, NULL, 10);
return gcoap_response(pdu, buf, len, COAP_CODE_CHANGED);
}
else {
return gcoap_response(pdu, buf, len, COAP_CODE_BAD_REQUEST);
}
}

return 0;
}

static ssize_t _riot_board_handler(coap_pkt_t *pdu, uint8_t *buf, size_t len, void *ctx)
{
(void)ctx;
gcoap_resp_init(pdu, buf, len, COAP_CODE_CONTENT);
coap_opt_add_format(pdu, COAP_FORMAT_TEXT);
size_t resp_len = coap_opt_finish(pdu, COAP_OPT_FINISH_PAYLOAD);

/* write the RIOT board name in the response buffer */
if (pdu->payload_len >= strlen(RIOT_BOARD)) {
memcpy(pdu->payload, RIOT_BOARD, strlen(RIOT_BOARD));
return resp_len + strlen(RIOT_BOARD);
}
else {
puts("gcoap_cli: msg buffer too small");
return gcoap_response(pdu, buf, len, COAP_CODE_INTERNAL_SERVER_ERROR);
}
}

static bool _parse_endpoint(sock_udp_ep_t *remote,
const char *addr_str, const char *port_str)
{
Expand Down Expand Up @@ -307,6 +187,12 @@ static size_t _send(uint8_t *buf, size_t len, char *addr_str, char *port_str)
return bytes_sent;
}

static int _print_usage(char **argv)
{
printf("usage: %s <get|post|put|ping|proxy|info>\n", argv[0]);
return 1;
}

int gcoap_cli_cmd(int argc, char **argv)
{
/* Ordered like the RFC method code numbers, but off by 1. GET is code 0. */
Expand All @@ -317,7 +203,7 @@ int gcoap_cli_cmd(int argc, char **argv)

if (argc == 1) {
/* show help for main commands */
goto end;
return _print_usage(argv);
}

if (strcmp(argv[1], "info") == 0) {
Expand Down Expand Up @@ -376,7 +262,7 @@ int gcoap_cli_cmd(int argc, char **argv)
}
}
if (code_pos == -1) {
goto end;
return _print_usage(argv);
}

/* parse options */
Expand Down Expand Up @@ -447,22 +333,7 @@ int gcoap_cli_cmd(int argc, char **argv)
}
else {
/* send Observe notification for /cli/stats */
switch (gcoap_obs_init(&pdu, &buf[0], CONFIG_GCOAP_PDU_BUF_SIZE,
&_resources[0])) {
case GCOAP_OBS_INIT_OK:
DEBUG("gcoap_cli: creating /cli/stats notification\n");
coap_opt_add_format(&pdu, COAP_FORMAT_TEXT);
len = coap_opt_finish(&pdu, COAP_OPT_FINISH_PAYLOAD);
len += fmt_u16_dec((char *)pdu.payload, req_count);
gcoap_obs_send(&buf[0], len, &_resources[0]);
break;
case GCOAP_OBS_INIT_UNUSED:
DEBUG("gcoap_cli: no observer for /cli/stats\n");
break;
case GCOAP_OBS_INIT_ERR:
DEBUG("gcoap_cli: error initializing /cli/stats notification\n");
break;
}
notify_observers();
}
return 0;
}
Expand All @@ -475,26 +346,5 @@ int gcoap_cli_cmd(int argc, char **argv)
return 1;
}

end:
printf("usage: %s <get|post|put|ping|proxy|info>\n", argv[0]);
return 1;
}

void gcoap_cli_init(void)
{
#if IS_USED(MODULE_GCOAP_DTLS)
int res = credman_add(&credential);
if (res < 0 && res != CREDMAN_EXIST) {
/* ignore duplicate credentials */
printf("gcoap: cannot add credential to system: %d\n", res);
return;
}
sock_dtls_t *gcoap_sock_dtls = gcoap_get_sock_dtls();
res = sock_dtls_add_credential(gcoap_sock_dtls, GCOAP_DTLS_CREDENTIAL_TAG);
if (res < 0) {
printf("gcoap: cannot add credential to DTLS sock: %d\n", res);
}
#endif

gcoap_register_listener(&_listener);
return _print_usage(argv);
}
65 changes: 65 additions & 0 deletions examples/gcoap/gcoap_example.h
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Original file line number Diff line number Diff line change
@@ -0,0 +1,65 @@
/*
* Copyright (C) 2020 Otto-von-Guericke-Universität Magdeburg
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for more
* details.
*/

/**
* @ingroup examples
* @{
*
* @file
* @brief gcoap example
*
* @author Ken Bannister <kb2ma@runbox.com>
*/

#ifndef GCOAP_EXAMPLE_H
#define GCOAP_EXAMPLE_H

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "fmt.h"
#include "net/gcoap.h"
#include "net/utils.h"
#include "od.h"

#ifdef __cplusplus
extern "C" {
#endif

extern uint16_t req_count; /**< Counts requests sent by CLI. */

/**
* @brief Shell interface exposing the client side features of gcoap
* @param argc Number of shell arguments (including shell command name)
* @param argv Shell argument values (including shell command name)
* @return Exit status of the shell command
*/
int gcoap_cli_cmd(int argc, char **argv);

/**
* @brief Registers the CoAP resources exposed in the example app
*
* Run this exactly one during startup.
*/
void server_init(void);

/**
* @brief Notifies all observers registered to /cli/stats - if any
*
* Call this whenever the count of successfully send client requests changes
*/
void notify_observers(void);

#ifdef __cplusplus
}
#endif

#endif /* CC110X_H */
/** @} */
7 changes: 3 additions & 4 deletions examples/gcoap/main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,12 +24,11 @@
#include "net/gcoap.h"
#include "shell.h"

#include "gcoap_example.h"

#define MAIN_QUEUE_SIZE (4)
static msg_t _main_msg_queue[MAIN_QUEUE_SIZE];

extern int gcoap_cli_cmd(int argc, char **argv);
extern void gcoap_cli_init(void);

static const shell_command_t shell_commands[] = {
{ "coap", "CoAP example", gcoap_cli_cmd },
{ NULL, NULL, NULL }
Expand All @@ -39,7 +38,7 @@ int main(void)
{
/* for the thread running the shell */
msg_init_queue(_main_msg_queue, MAIN_QUEUE_SIZE);
gcoap_cli_init();
server_init();
puts("gcoap example app");

/* start shell */
Expand Down
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