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drivers: wifi: esp_at: handle commas in SSIDs during scan and status
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SSIDs can contains commas (,) when receiving scan results (+CWLAP) or
status (+CWJAP) over AT command from ESP-AT chip. This is in conflict with
modem subsystem argument parsing, which separates arguments automatically
whenever comma is encountered.

Use a direct modem command parsing, so that commas within quoted strings
are taken into account to be part of that string, instead of being treated
as delimiter.

This solves `wifi scan` and `wifi status` Zephyr shell commands output, for
networks containing commas (like "My_2,4GHz_AP") as part of SSID.

Signed-off-by: Marcin Niestroj <[email protected]>
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@mniestroj @fabiobaltieri
mniestroj authored and fabiobaltieri committed Feb 28, 2024
1 parent de30757 commit a6b0600
Showing 1 changed file with 145 additions and 29 deletions.
174 changes: 145 additions & 29 deletions drivers/wifi/esp_at/esp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -253,64 +253,164 @@ MODEM_CMD_DEFINE(on_cmd_cipstamac)
return 0;
}

static int esp_pull_quoted(char **str, char *str_end, char **unquoted)
{
if (**str != '"') {
return -EBADMSG;
}

(*str)++;

*unquoted = *str;

while (*str < str_end) {
if (**str == '"') {
**str = '\0';
(*str)++;

if (**str == ',') {
(*str)++;
}

return 0;
}

(*str)++;
}

return -EAGAIN;
}

static int esp_pull(char **str, char *str_end)
{
while (*str < str_end) {
if (**str == ',' || **str == '\r' || **str == '\n') {
char last_c = **str;

**str = '\0';

if (last_c == ',') {
(*str)++;
}

return 0;
}

(*str)++;
}

return -EAGAIN;
}

static int esp_pull_raw(char **str, char *str_end, char **raw)
{
*raw = *str;

return esp_pull(str, str_end);
}

/* +CWLAP:(sec,ssid,rssi,channel) */
/* with: CONFIG_WIFI_ESP_AT_SCAN_MAC_ADDRESS: +CWLAP:<ecn>,<ssid>,<rssi>,<mac>,<ch>*/
MODEM_CMD_DEFINE(on_cmd_cwlap)
MODEM_CMD_DIRECT_DEFINE(on_cmd_cwlap)
{
struct esp_data *dev = CONTAINER_OF(data, struct esp_data,
cmd_handler_data);
struct wifi_scan_result res = { 0 };
int i;
char cwlap_buf[sizeof("\"0\",\"\",-100,\"xx:xx:xx:xx:xx:xx\",12") +
WIFI_SSID_MAX_LEN * 2 + 1];
char *ecn;
char *ssid;
char *mac;
char *channel;
char *rssi;
long ecn_id;
int err;

len = net_buf_linearize(cwlap_buf, sizeof(cwlap_buf) - 1,
data->rx_buf, 0, sizeof(cwlap_buf) - 1);
cwlap_buf[len] = '\0';

char *str = &cwlap_buf[sizeof("+CWJAP:(") - 1];
char *str_end = cwlap_buf + len;

err = esp_pull_raw(&str, str_end, &ecn);
if (err) {
return err;
}

i = strtol(&argv[0][1], NULL, 10);
if (i == 0) {
ecn_id = strtol(ecn, NULL, 10);
if (ecn_id == 0) {
res.security = WIFI_SECURITY_TYPE_NONE;
} else {
res.security = WIFI_SECURITY_TYPE_PSK;
}

argv[1] = str_unquote(argv[1]);
i = strlen(argv[1]);
if (i > sizeof(res.ssid)) {
i = sizeof(res.ssid);
err = esp_pull_quoted(&str, str_end, &ssid);
if (err) {
return err;
}

memcpy(res.ssid, argv[1], i);
res.ssid_length = i;
res.rssi = strtol(argv[2], NULL, 10);
err = esp_pull_raw(&str, str_end, &rssi);
if (err) {
return err;
}

if (strlen(ssid) > WIFI_SSID_MAX_LEN) {
return -EBADMSG;
}

strncpy(res.ssid, ssid, sizeof(res.ssid));
res.ssid_length = MIN(sizeof(res.ssid), strlen(ssid));

res.rssi = strtol(rssi, NULL, 10);

if (IS_ENABLED(CONFIG_WIFI_ESP_AT_SCAN_MAC_ADDRESS)) {
argv[3] = str_unquote(argv[3]);
err = esp_pull_quoted(&str, str_end, &mac);
if (err) {
return err;
}

res.mac_length = WIFI_MAC_ADDR_LEN;
if (net_bytes_from_str(res.mac, sizeof(res.mac), argv[3]) < 0) {
if (net_bytes_from_str(res.mac, sizeof(res.mac), mac) < 0) {
LOG_ERR("Invalid MAC address");
res.mac_length = 0;
}
res.channel = (argc > 4) ? strtol(argv[4], NULL, 10) : -1;
} else {
res.channel = strtol(argv[3], NULL, 10);
}

err = esp_pull_raw(&str, str_end, &channel);
if (err) {
return err;
}

if (dev->scan_cb) {
dev->scan_cb(dev->net_iface, 0, &res);
}

return 0;
return str - cwlap_buf;
}

/* +CWJAP:(ssid,bssid,channel,rssi) */
MODEM_CMD_DEFINE(on_cmd_cwjap)
MODEM_CMD_DIRECT_DEFINE(on_cmd_cwjap)
{
struct esp_data *dev = CONTAINER_OF(data, struct esp_data,
cmd_handler_data);
struct wifi_iface_status *status = dev->wifi_status;
const char *ssid = str_unquote(argv[0]);
const char *bssid = str_unquote(argv[1]);
const char *channel = argv[2];
const char *rssi = argv[3];
char cwjap_buf[sizeof("\"\",\"xx:xx:xx:xx:xx:xx\",12,-100") +
WIFI_SSID_MAX_LEN * 2 + 1];
uint8_t flags = dev->flags;
char *ssid;
char *bssid;
char *channel;
char *rssi;
int err;

len = net_buf_linearize(cwjap_buf, sizeof(cwjap_buf) - 1,
data->rx_buf, 0, sizeof(cwjap_buf) - 1);
cwjap_buf[len] = '\0';

char *str = &cwjap_buf[sizeof("+CWJAP:") - 1];
char *str_end = cwjap_buf + len;

status->band = WIFI_FREQ_BAND_2_4_GHZ;
status->iface_mode = WIFI_MODE_INFRA;

Expand All @@ -322,6 +422,26 @@ MODEM_CMD_DEFINE(on_cmd_cwjap)
status->state = WIFI_STATE_DISCONNECTED;
}

err = esp_pull_quoted(&str, str_end, &ssid);
if (err) {
return err;
}

err = esp_pull_quoted(&str, str_end, &bssid);
if (err) {
return err;
}

err = esp_pull_raw(&str, str_end, &channel);
if (err) {
return err;
}

err = esp_pull_raw(&str, str_end, &rssi);
if (err) {
return err;
}

strncpy(status->ssid, ssid, sizeof(status->ssid));
status->ssid_len = strnlen(status->ssid, sizeof(status->ssid));

Expand All @@ -334,7 +454,7 @@ MODEM_CMD_DEFINE(on_cmd_cwjap)
status->channel = strtol(channel, NULL, 10);
status->rssi = strtol(rssi, NULL, 10);

return 0;
return str - cwjap_buf;
}

static void esp_dns_work(struct k_work *work)
Expand Down Expand Up @@ -844,7 +964,7 @@ static void esp_mgmt_iface_status_work(struct k_work *work)
struct wifi_iface_status *status = data->wifi_status;
int ret;
static const struct modem_cmd cmds[] = {
MODEM_CMD("+CWJAP:", on_cmd_cwjap, 4U, ","),
MODEM_CMD_DIRECT("+CWJAP:", on_cmd_cwjap),
};

ret = esp_cmd_send(data, cmds, ARRAY_SIZE(cmds), "AT+CWJAP?",
Expand Down Expand Up @@ -891,11 +1011,7 @@ static void esp_mgmt_scan_work(struct k_work *work)
struct esp_data *dev;
int ret;
static const struct modem_cmd cmds[] = {
#if defined(CONFIG_WIFI_ESP_AT_SCAN_MAC_ADDRESS)
MODEM_CMD("+CWLAP:", on_cmd_cwlap, 5U, ","),
#else
MODEM_CMD("+CWLAP:", on_cmd_cwlap, 4U, ","),
#endif
MODEM_CMD_DIRECT("+CWLAP:", on_cmd_cwlap),
};

dev = CONTAINER_OF(work, struct esp_data, scan_work);
Expand Down

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