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fix: master tcp reconnection issue #173

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fix: master tcp reconnection issue #173

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84c1f8d
fix: master tcp repair connection on error or disconnection
alisitsyn May 21, 2026
dd25e20
fix: utils check node connection alive
alisitsyn May 21, 2026
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27 changes: 21 additions & 6 deletions modbus/mb_ports/tcp/port_tcp_master.c
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Original file line number Diff line number Diff line change
Expand Up @@ -324,10 +324,22 @@ mb_uid_info_t *mbm_port_tcp_get_slave_info(mb_port_base_t *inst, uint8_t uid, mb
{
mbm_tcp_port_t *port_obj = __containerof(inst, mbm_tcp_port_t, base);
mb_uid_info_t *addr_info = NULL;
mb_node_info_t *info_ptr = mb_drv_get_node_info_from_addr(port_obj->drv_obj, uid);
if (info_ptr && (MB_GET_NODE_STATE(info_ptr) >= exp_state)) {
addr_info = &info_ptr->addr_info;
mb_node_info_t *node_ptr = mb_drv_get_node_info_from_addr(port_obj->drv_obj, uid);
if (!node_ptr) {
return NULL;
} else {
if (MB_GET_NODE_STATE(node_ptr) >= exp_state) {
addr_info = &node_ptr->addr_info;
} else {
ESP_LOGW(TAG, "The node #%d, uid = %d, is not alive, try to repair connection.", node_ptr->index, node_ptr->addr_info.uid);
addr_info = NULL;
if ((node_ptr->sock_id < 0) && FD_ISSET(node_ptr->index, &port_obj->drv_obj->open_set)) {
// Try to restore node connection as soon as possible
DRIVER_SEND_EVENT(port_obj->drv_obj, MB_EVENT_RESOLVE, node_ptr->index);
}
}
}

return addr_info;
}

Expand Down Expand Up @@ -478,21 +490,24 @@ MB_EVENT_HANDLER(mbm_on_connect)
drv_obj->node_conn_count--;
}
mb_drv_unlock(ctx);
DRIVER_SEND_EVENT(ctx, MB_EVENT_CLOSE, event_info->opt_fd);
port_close_connection(node_ptr);
} else {
ESP_LOGD(TAG, "%p, slave: #%d, sock:%d, IP:%s, connection is in progress.",
ctx, (int)event_info->opt_fd, (int)node_ptr->sock_id,
node_ptr->addr_info.ip_addr_str);
MB_SET_NODE_STATE(node_ptr, MB_SOCK_STATE_CONNECTING);
vTaskDelay(MB_CONN_TICK_TIMEOUT);
// try to connect to slave and check connection again if it is not connected
DRIVER_SEND_EVENT(ctx, MB_EVENT_TIMEOUT, node_ptr->index);
// Follow reconnecion cycle
DRIVER_SEND_EVENT(ctx, MB_EVENT_CONNECT, event_info->opt_fd);
}
break;
case ERR_CONN:
ESP_LOGE(TAG, "Modbus connection phase, slave: %d (%s), connection error (%d).",
(int)event_info->opt_fd, node_ptr->addr_info.ip_addr_str, (int)err);
port_close_connection(node_ptr);
DRIVER_SEND_EVENT(ctx, MB_EVENT_TIMEOUT, node_ptr->index);
// On connection error, try to reconnect node as soon as possible
DRIVER_SEND_EVENT(ctx, MB_EVENT_RESOLVE, node_ptr->index);
break;
default:
ESP_LOGE(TAG, "Invalid error state, slave: %d (%s), error = %d.",
Expand Down
78 changes: 40 additions & 38 deletions modbus/mb_ports/tcp/port_tcp_utils.c
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Original file line number Diff line number Diff line change
Expand Up @@ -317,52 +317,54 @@ int port_keep_alive_enable(int sock, int timeout_sec)
return 0;
}

// Check connection for timeout helper
// Check if connection is alive
err_t port_check_alive(mb_node_info_t *info_ptr, uint32_t timeout_ms)
{
fd_set write_set;
fd_set err_set;
err_t err = -1;
struct timeval time_val;

if (info_ptr && info_ptr->sock_id != -1) {
FD_ZERO(&write_set);
FD_ZERO(&err_set);
FD_SET(info_ptr->sock_id, &write_set);
FD_SET(info_ptr->sock_id, &err_set);
port_ms_to_tv(timeout_ms, &time_val);
// Check if the socket is writable
err = select(info_ptr->sock_id + 1, NULL, &write_set, &err_set, &time_val);
if ((err < 0) || FD_ISSET(info_ptr->sock_id, &err_set)) {
if (errno == EINPROGRESS) {
err = ERR_INPROGRESS;
} else {
ESP_LOGV(TAG, MB_NODE_FMT(" connection, select write err(errno) = %d(%d)."),
info_ptr->index, info_ptr->sock_id, info_ptr->addr_info.ip_addr_str, err, (int)errno);
err = ERR_CONN;
}
} else if (err == 0) {
ESP_LOGV(TAG, "Socket(#%d)(%s), connection timeout occurred, err(errno) = %d(%d).",
info_ptr->sock_id, info_ptr->addr_info.ip_addr_str, err, (int)errno);
return ERR_INPROGRESS;
} else {
int opt_err = 0;
uint32_t opt_len = sizeof(opt_err);
// Check socket error
err = getsockopt(info_ptr->sock_id, SOL_SOCKET, SO_ERROR, (void *)&opt_err, (socklen_t *)&opt_len);
if (opt_err != 0) {
ESP_LOGD(TAG, "Socket(#%d)(%s), sock error occurred (%d).",
info_ptr->sock_id, info_ptr->addr_info.ip_addr_str, opt_err);
return ERR_CONN;
}
ESP_LOGV(TAG, "Socket(#%d)(%s), is alive.",
info_ptr->sock_id, info_ptr->addr_info.ip_addr_str);
return ERR_OK;
}
} else {
err = ERR_CONN;
if (!info_ptr || info_ptr->sock_id == -1) {
return ERR_VAL;
}
FD_ZERO(&write_set);
FD_ZERO(&err_set);
FD_SET(info_ptr->sock_id, &write_set);
FD_SET(info_ptr->sock_id, &err_set);
port_ms_to_tv(timeout_ms, &time_val);
// Check if the socket is writable and no errors
err = select(info_ptr->sock_id + 1, NULL, &write_set, &err_set, &time_val);
if (err < 0 || FD_ISSET(info_ptr->sock_id, &err_set)) {
ESP_LOGV(TAG, MB_NODE_FMT(" connection, select write err(errno) = %d(%d)."),
info_ptr->index, info_ptr->sock_id, info_ptr->addr_info.ip_addr_str, err, (int)errno);
return ERR_CONN;
}
return err;
if (err == 0) {
ESP_LOGV(TAG, "Socket(#%d)(%s), connection timeout occurred, err(errno) = %d(%d).",
info_ptr->sock_id, info_ptr->addr_info.ip_addr_str, err, (int)errno);
return ERR_INPROGRESS;
}
int opt_err = 0;
socklen_t opt_len = sizeof(opt_err);
// Check socket error
if (getsockopt(info_ptr->sock_id, SOL_SOCKET, SO_ERROR, &opt_err, &opt_len) < 0) {
ESP_LOGV(TAG, "Socket(#%d)(%s), sock error occurred (%d).",
info_ptr->sock_id, info_ptr->addr_info.ip_addr_str, opt_err);
return ERR_CONN;
}
if (opt_err == 0) {
ESP_LOGV(TAG, "Socket(#%d)(%s), is alive.",
info_ptr->sock_id, info_ptr->addr_info.ip_addr_str);
return ERR_OK;
}
if (opt_err == EINPROGRESS || opt_err == EALREADY) {
return ERR_INPROGRESS;
}
ESP_LOGV(TAG, "Socket(#%d)(%s), sock error occurred (%d).",
info_ptr->sock_id, info_ptr->addr_info.ip_addr_str, opt_err);
errno = opt_err; // optional, only for logging
return ERR_CONN;
}

// Unblocking connect function
Expand Down