Add Z_FEATURE_TCP_NODELAY (#723)

* refactor: recopy buffers instead of bytes in siphon

* feat: activate TCP_NO_DELAY

CMakeLists.txt

@@ -203,6 +203,7 @@ set(Z_FEATURE_LINK_UDP_UNICAST 1 CACHE STRING "Toggle UDP unicast links")
 set(Z_FEATURE_MULTICAST_TRANSPORT 1 CACHE STRING "Toggle multicast transport")
 set(Z_FEATURE_UNICAST_TRANSPORT 1 CACHE STRING "Toggle unicast transport")
 set(Z_FEATURE_RAWETH_TRANSPORT 0 CACHE STRING "Toggle raw ethernet transport")
+set(Z_FEATURE_TCP_NODELAY 1 CACHE STRING "Toggle TCP_NODELAY")
 
 add_compile_definitions("Z_BUILD_DEBUG=$<CONFIG:Debug>")
 message(STATUS "Building with feature confing:\n\

include/zenoh-pico/config.h

@@ -41,6 +41,7 @@
 #define Z_FEATURE_UNICAST_TRANSPORT 1
 #define Z_FEATURE_FRAGMENTATION 1
 #define Z_FEATURE_ENCODING_VALUES 1
+#define Z_FEATURE_TCP_NODELAY 1
 // End of CMake generation
 
 /*------------------ Runtime configuration properties ------------------*/

include/zenoh-pico/config.h.in

@@ -41,6 +41,7 @@
 #define Z_FEATURE_UNICAST_TRANSPORT @Z_FEATURE_UNICAST_TRANSPORT@
 #define Z_FEATURE_FRAGMENTATION @Z_FEATURE_FRAGMENTATION@
 #define Z_FEATURE_ENCODING_VALUES @Z_FEATURE_ENCODING_VALUES@
+#define Z_FEATURE_TCP_NODELAY @Z_FEATURE_TCP_NODELAY@
 // End of CMake generation
 
 /*------------------ Runtime configuration properties ------------------*/

src/protocol/iobuf.c

@@ -519,14 +519,30 @@ _z_zbuf_t _z_wbuf_to_zbuf(const _z_wbuf_t *wbf) {
 
 z_result_t _z_wbuf_siphon(_z_wbuf_t *dst, _z_wbuf_t *src, size_t length) {
     z_result_t ret = _Z_RES_OK;
-
-    for (size_t i = 0; i < length; i++) {
-        ret = _z_wbuf_write(dst, _z_wbuf_read(src));
-        if (ret != _Z_RES_OK) {
-            break;
-        }
+    size_t llength = length;
+    _z_iosli_t *wios = _z_wbuf_get_iosli(dst, dst->_w_idx);
+    size_t writable = _z_iosli_writable(wios);
+
+    // Siphon does not work (as of now) on expandable dst buffers
+    if (writable >= length) {
+        do {
+            assert(src->_r_idx <= src->_w_idx);
+            _z_iosli_t *rios = _z_wbuf_get_iosli(src, src->_r_idx);
+            size_t readable = _z_iosli_readable(rios);
+            if (readable > (size_t)0) {
+                size_t to_read = (readable <= llength) ? readable : llength;
+                uint8_t *w_pos = _z_ptr_u8_offset(wios->_buf, (ptrdiff_t)wios->_w_pos);
+                (void)memcpy(w_pos, rios->_buf + rios->_r_pos, to_read);
+                rios->_r_pos = rios->_r_pos + to_read;
+                llength -= to_read;
+                wios->_w_pos += to_read;
+            } else {
+                src->_r_idx++;
+            }
+        } while (llength > (size_t)0);
+    } else {
+        ret = _Z_ERR_TRANSPORT_NO_SPACE;
     }
-
     return ret;
 }
 

src/system/arduino/esp32/network.cpp

@@ -64,6 +64,13 @@ z_result_t _z_open_tcp(_z_sys_net_socket_t *sock, const _z_sys_net_endpoint_t re
             ret = _Z_ERR_GENERIC;
         }
 
+#if Z_FEATURE_TCP_NODELAY == 1
+        if ((ret == _Z_RES_OK) &&
+            (setsockopt(sock->_fd, IPPROTO_TCP, TCP_NODELAY, (void *)&optflag, sizeof(optflag)) < 0)) {
+            ret = _Z_ERR_GENERIC;
+        }
+#endif
+
 #if LWIP_SO_LINGER == 1
         struct linger ling;
         ling.l_onoff = 1;

src/system/espidf/network.c

@@ -60,6 +60,13 @@ z_result_t _z_open_tcp(_z_sys_net_socket_t *sock, const _z_sys_net_endpoint_t re
             ret = _Z_ERR_GENERIC;
         }
 
+#if Z_FEATURE_TCP_NODELAY == 1
+        if ((ret == _Z_RES_OK) &&
+            (setsockopt(sock->_fd, IPPROTO_TCP, TCP_NODELAY, (void *)&optflag, sizeof(optflag)) < 0)) {
+            ret = _Z_ERR_GENERIC;
+        }
+#endif
+
 #if LWIP_SO_LINGER == 1
         struct linger ling;
         ling.l_onoff = 1;

src/system/unix/network.c

@@ -18,6 +18,7 @@
 #include <net/if.h>
 #include <netdb.h>
 #include <netinet/in.h>
+#include <netinet/tcp.h>
 #include <stdbool.h>
 #include <stddef.h>
 #include <string.h>
@@ -71,7 +72,12 @@ z_result_t _z_open_tcp(_z_sys_net_socket_t *sock, const _z_sys_net_endpoint_t re
             (setsockopt(sock->_fd, SOL_SOCKET, SO_KEEPALIVE, (void *)&flags, sizeof(flags)) < 0)) {
             ret = _Z_ERR_GENERIC;
         }
-
+#if Z_FEATURE_TCP_NODELAY == 1
+        if ((ret == _Z_RES_OK) &&
+            (setsockopt(sock->_fd, IPPROTO_TCP, TCP_NODELAY, (void *)&flags, sizeof(flags)) < 0)) {
+            ret = _Z_ERR_GENERIC;
+        }
+#endif
         struct linger ling;
         ling.l_onoff = 1;
         ling.l_linger = Z_TRANSPORT_LEASE / 1000;

src/system/windows/network.c

@@ -75,6 +75,13 @@ z_result_t _z_open_tcp(_z_sys_net_socket_t *sock, const _z_sys_net_endpoint_t re
             ret = _Z_ERR_GENERIC;
         }
 
+#if Z_FEATURE_TCP_NODELAY == 1
+        if ((ret == _Z_RES_OK) &&
+            (setsockopt(sock->_sock._fd, IPPROTO_TCP, TCP_NODELAY, (void *)&flags, sizeof(flags)) < 0)) {
+            ret = _Z_ERR_GENERIC;
+        }
+#endif
+
         struct linger ling;
         ling.l_onoff = 1;
         ling.l_linger = Z_TRANSPORT_LEASE / 1000;

src/system/zephyr/network.c

@@ -24,6 +24,7 @@
 #include <stdbool.h>
 #include <stddef.h>
 #include <sys/socket.h>
+#include <zephyr/net/net_if.h>
 
 #include "zenoh-pico/collections/string.h"
 #include "zenoh-pico/config.h"
@@ -68,6 +69,14 @@ z_result_t _z_open_tcp(_z_sys_net_socket_t *sock, const _z_sys_net_endpoint_t re
             // ret = _Z_ERR_GENERIC;
         }
 
+#if Z_FEATURE_TCP_NODELAY == 1
+        int optflag = 1;
+        if ((ret == _Z_RES_OK) &&
+            (setsockopt(sock->_fd, IPPROTO_TCP, TCP_NODELAY, (void *)&optflag, sizeof(optflag)) < 0)) {
+            ret = _Z_ERR_GENERIC;
+        }
+#endif
+
 #if LWIP_SO_LINGER == 1
         struct linger ling;
         ling.l_onoff = 1;

src/transport/multicast/tx.c

@@ -141,6 +141,8 @@ z_result_t _z_multicast_send_n_msg(_z_session_t *zn, const _z_network_message_t
                             if (ret == _Z_RES_OK) {
                                 ztm->_transmitted = true;  // Mark the session that we have transmitted data
                             }
+                        } else {
+                            _Z_ERROR("Fragment serialization failed with err %d", ret);
                         }
                     }
                 }

src/transport/unicast/tx.c

@@ -150,6 +150,8 @@ z_result_t _z_unicast_send_n_msg(_z_session_t *zn, const _z_network_message_t *n
                             if (ret == _Z_RES_OK) {
                                 ztu->_transmitted = true;  // Mark the session that we have transmitted data
                             }
+                        } else {
+                            _Z_ERROR("Fragment serialization failed with err %d", ret);
                         }
                     }
                 }