Modify esp-tls and tcp_transport to support keep alive for tcp and ssl connection

Closes IDFGH-4543

components/esp-tls/esp_tls.c

@@ -161,6 +161,34 @@ static void ms_to_timeval(int timeout_ms, struct timeval *tv)
     tv->tv_usec = (timeout_ms % 1000) * 1000;
 }
 
+static int esp_tls_tcp_enable_keep_alive(int fd, tls_keep_alive_cfg_t *cfg)
+{
+    int keep_alive_enable = 1;
+    int keep_alive_idle = cfg->keep_alive_idle;
+    int keep_alive_interval = cfg->keep_alive_interval;
+    int keep_alive_count = cfg->keep_alive_count;
+
+    ESP_LOGD(TAG, "Enable TCP keep alive. idle: %d, interval: %d, count: %d", keep_alive_idle, keep_alive_interval, keep_alive_count);
+    if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &keep_alive_enable, sizeof(keep_alive_enable)) != 0) {
+        ESP_LOGE(TAG, "Fail to setsockopt SO_KEEPALIVE");
+        return -1;
+    }
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &keep_alive_idle, sizeof(keep_alive_idle)) != 0) {
+        ESP_LOGE(TAG, "Fail to setsockopt TCP_KEEPIDLE");
+        return -1;
+    }
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &keep_alive_interval, sizeof(keep_alive_interval)) != 0) {
+        ESP_LOGE(TAG, "Fail to setsockopt TCP_KEEPINTVL");
+        return -1;
+    }
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &keep_alive_count, sizeof(keep_alive_count)) != 0) {
+        ESP_LOGE(TAG, "Fail to setsockopt TCP_KEEPCNT");
+        return -1;
+    }
+
+    return 0;
+}
+
 static esp_err_t esp_tcp_connect(const char *host, int hostlen, int port, int *sockfd, const esp_tls_t *tls, const esp_tls_cfg_t *cfg)
 {
     esp_err_t ret;
@@ -199,6 +227,12 @@ static esp_err_t esp_tcp_connect(const char *host, int hostlen, int port, int *s
             ms_to_timeval(cfg->timeout_ms, &tv);
             setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
             setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+            if (cfg->keep_alive_cfg && cfg->keep_alive_cfg->keep_alive_enable) {
+                if (esp_tls_tcp_enable_keep_alive(fd, cfg->keep_alive_cfg) < 0) {
+                    ESP_LOGE(TAG, "Error setting keep-alive");
+                    goto err_freesocket;
+                }
+            }
         }
         if (cfg->non_block) {
             int flags = fcntl(fd, F_GETFL, 0);

components/esp-tls/esp_tls.h

@@ -126,6 +126,16 @@ typedef struct psk_key_hint {
     const char* hint;                       /*!< hint in PSK authentication mode in string format */
 } psk_hint_key_t;
 
+/**
+*  @brief Keep alive parameters structure
+*/
+typedef struct tls_keep_alive_cfg {
+    bool keep_alive_enable;               /*!< Enable keep-alive timeout */
+    int keep_alive_idle;                  /*!< Keep-alive idle time (second) */
+    int keep_alive_interval;              /*!< Keep-alive interval time (second) */
+    int keep_alive_count;                 /*!< Keep-alive packet retry send count */
+} tls_keep_alive_cfg_t;
+
 /**
  * @brief      ESP-TLS configuration parameters
  *
@@ -213,6 +223,8 @@ typedef struct esp_tls_cfg {
 
     bool skip_common_name;                  /*!< Skip any validation of server certificate CN field */
 
+    tls_keep_alive_cfg_t *keep_alive_cfg;   /*!< Enable TCP keep-alive timeout for SSL connection */
+
     const psk_hint_key_t* psk_hint_key;     /*!< Pointer to PSK hint and key. if not NULL (and certificates are NULL)
                                                  then PSK authentication is enabled with configured setup.
                                                  Important note: the pointer must be valid for connection */

components/tcp_transport/include/esp_transport.h

@@ -16,11 +16,21 @@
 #define _ESP_TRANSPORT_H_
 
 #include <esp_err.h>
+#include <stdbool.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+/**
+*  @brief Keep alive parameters structure
+*/
+typedef struct esp_transport_keepalive {
+    bool            keep_alive_enable;      /*!< Enable keep-alive timeout */
+    int             keep_alive_idle;        /*!< Keep-alive idle time (second) */
+    int             keep_alive_interval;    /*!< Keep-alive interval time (second) */
+    int             keep_alive_count;       /*!< Keep-alive packet retry send count */
+} esp_transport_keep_alive_t;
 
 typedef struct esp_transport_internal* esp_transport_list_handle_t;
 typedef struct esp_transport_item_t* esp_transport_handle_t;

components/tcp_transport/include/esp_transport_ssl.h

@@ -165,6 +165,14 @@ void esp_transport_ssl_set_ds_data(esp_transport_handle_t t, void *ds_data);
  */
 void esp_transport_ssl_set_psk_key_hint(esp_transport_handle_t t, const psk_hint_key_t* psk_hint_key);
 
+/**
+ * @brief      Set keep-alive status in current ssl context
+ *
+ * @param[in]  t               ssl transport
+ * @param[in]  keep_alive_cfg  The handle for keep-alive configuration
+ */
+void esp_transport_ssl_set_keep_alive(esp_transport_handle_t t, esp_transport_keep_alive_t *keep_alive_cfg);
+
 #ifdef __cplusplus
 }
 #endif

components/tcp_transport/include/esp_transport_tcp.h

@@ -21,6 +21,15 @@
 extern "C" {
 #endif
 
+/**
+ * @brief      Set TCP keep-alive configuration
+ *
+ * @param[in]  t               The transport handle
+ * @param[in]  keep_alive_cfg  The keep-alive config
+ *
+ */
+void esp_transport_tcp_set_keep_alive(esp_transport_handle_t t, esp_transport_keep_alive_t *keep_alive_cfg);
+
 /**
  * @brief      Create TCP transport, the transport handle must be release esp_transport_destroy callback
  *

components/tcp_transport/private_include/esp_transport_internal.h

@@ -39,6 +39,7 @@ struct esp_transport_item_t {
     get_socket_func        _get_socket;             /*!< Function returning the transport's socket */
     struct esp_transport_error_s*    error_handle;  /*!< Error handle (based on esp-tls error handle)
                                                      * extended with transport's specific errors */
+    esp_transport_keep_alive_t *keep_alive_cfg;     /*!< TCP keep-alive config */
 
     STAILQ_ENTRY(esp_transport_item_t) next;
 };

components/tcp_transport/transport_ssl.c

@@ -313,6 +313,14 @@ void esp_transport_ssl_set_ds_data(esp_transport_handle_t t, void *ds_data)
     }
 }
 
+void esp_transport_ssl_set_keep_alive(esp_transport_handle_t t, esp_transport_keep_alive_t *keep_alive_cfg)
+{
+    transport_ssl_t *ssl = esp_transport_get_context_data(t);
+    if (t && ssl) {
+        ssl->cfg.keep_alive_cfg = (tls_keep_alive_cfg_t *)keep_alive_cfg;
+    }
+}
+
 esp_transport_handle_t esp_transport_ssl_init(void)
 {
     esp_transport_handle_t t = esp_transport_init();

components/tcp_transport/transport_tcp.c

@@ -52,6 +52,34 @@ static int resolve_dns(const char *host, struct sockaddr_in *ip)
     return ESP_OK;
 }
 
+static int tcp_enable_keep_alive(int fd, esp_transport_keep_alive_t *keep_alive_cfg)
+{
+    int keep_alive_enable = 1;
+    int keep_alive_idle = keep_alive_cfg->keep_alive_idle;
+    int keep_alive_interval = keep_alive_cfg->keep_alive_interval;
+    int keep_alive_count = keep_alive_cfg->keep_alive_count;
+
+    ESP_LOGD(TAG, "Enable TCP keep alive. idle: %d, interval: %d, count: %d", keep_alive_idle, keep_alive_interval, keep_alive_count);
+    if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &keep_alive_enable, sizeof(keep_alive_enable)) != 0) {
+        ESP_LOGE(TAG, "Fail to setsockopt SO_KEEPALIVE");
+        return -1;
+    }
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &keep_alive_idle, sizeof(keep_alive_idle)) != 0) {
+        ESP_LOGE(TAG, "Fail to setsockopt TCP_KEEPIDLE");
+        return -1;
+    }
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &keep_alive_interval, sizeof(keep_alive_interval)) != 0) {
+        ESP_LOGE(TAG, "Fail to setsockopt TCP_KEEPINTVL");
+        return -1;
+    }
+    if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &keep_alive_count, sizeof(keep_alive_count)) != 0) {
+        ESP_LOGE(TAG, "Fail to setsockopt TCP_KEEPCNT");
+        return -1;
+    }
+
+    return 0;
+}
+
 static int tcp_connect(esp_transport_handle_t t, const char *host, int port, int timeout_ms)
 {
     struct sockaddr_in remote_ip;
@@ -81,7 +109,13 @@ static int tcp_connect(esp_transport_handle_t t, const char *host, int port, int
 
     setsockopt(tcp->sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
     setsockopt(tcp->sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
-
+    // Set socket keep-alive option
+    if (t->keep_alive_cfg && t->keep_alive_cfg->keep_alive_enable) {
+        if (tcp_enable_keep_alive(tcp->sock, t->keep_alive_cfg) < 0) {
+            ESP_LOGE(TAG, "Error to set tcp [socket=%d] keep-alive", tcp->sock);
+            goto error;
+        }
+    }
     // Set socket to non-blocking
     int flags;
     if ((flags = fcntl(tcp->sock, F_GETFL, NULL)) < 0) {
@@ -251,6 +285,13 @@ static int tcp_get_socket(esp_transport_handle_t t)
     return -1;
 }
 
+void esp_transport_tcp_set_keep_alive(esp_transport_handle_t t, esp_transport_keep_alive_t *keep_alive_cfg)
+{
+    if (t && keep_alive_cfg) {
+        t->keep_alive_cfg = keep_alive_cfg;
+    }
+}
+
 esp_transport_handle_t esp_transport_tcp_init(void)
 {
     esp_transport_handle_t t = esp_transport_init();