drop non portable SOL_TCP / fix MacOS v2 (#680)

* Revert "Fix compilation on MacOS"

in order to another solution

* src: use IPPROTO_TCP in place of SOL_TCP

* use the more specific IPPROTO_TCP type for setsockopt
* fixes build on MacOS

src/edge_utils.c:891:31: error: use of undeclared identifier 'SOL_TCP'; did you mean 'FPP_TCP'?
        setsockopt(eee->sock, SOL_TCP, TCP_NODELAY, &value, sizeof(value));

src/edge_utils.c:894:31: error: use of undeclared identifier 'SOL_TCP'
        setsockopt(eee->sock, SOL_TCP, TCP_CORK, &value, sizeof(value));
                              ^
src/edge_utils.c:894:40: error: use of undeclared identifier 'TCP_CORK'
        setsockopt(eee->sock, SOL_TCP, TCP_CORK, &value, sizeof(value));

* include/n2n.h: drop redefiniton of SOL_TCP for WIN32, as we don't use it anywhere now

* src: only use TCP_CORK on LINUX

* it's LINUX only and fails on Win32 and MacOS (man 7 tcp)

include/n2n.h

@@ -137,7 +137,6 @@
 #ifdef WIN32
 #include <winsock2.h>           /* for tcp */
 #define SHUT_RDWR   SD_BOTH     /* for tcp */
-#define SOL_TCP     IPPROTO_TCP /* for tcp */
 #include "win32/wintap.h"
 #include <sys/stat.h>
 #else
@@ -155,16 +154,10 @@
 #include "sn_selection.h"
 #include "network_traffic_filter.h"
 
-#include "header_encryption.h"
-#include "tf.h"
-
 /* ************************************** */
 
-#if !defined(SOL_TCP) && defined(IPPROTO_TCP)
-#define SOL_TCP IPPROTO_TCP
-#endif
-
-/* ************************************** */
+#include "header_encryption.h"
+#include "tf.h"
 
 #ifndef TRACE_ERROR
 #define TRACE_ERROR       0, __FILE__, __LINE__

src/edge_utils.c

@@ -888,10 +888,10 @@ static ssize_t sendto_sock (n2n_edge_t *eee, const void * buf,
     // if the connection is tcp, i.e. not the regular sock...
     if(eee->conf.connect_tcp) {
 
-        setsockopt(eee->sock, SOL_TCP, TCP_NODELAY, &value, sizeof(value));
+        setsockopt(eee->sock, IPPROTO_TCP, TCP_NODELAY, &value, sizeof(value));
         value = 1;
-#if !defined(WIN32) && !defined(__APPLE__)
-        setsockopt(eee->sock, SOL_TCP, TCP_CORK, &value, sizeof(value));
+#ifdef LINUX
+        setsockopt(eee->sock, IPPROTO_TCP, TCP_CORK, &value, sizeof(value));
 #endif
 
         // prepend packet length...
@@ -907,10 +907,10 @@ static ssize_t sendto_sock (n2n_edge_t *eee, const void * buf,
     // if the connection is tcp, i.e. not the regular sock...
     if(eee->conf.connect_tcp) {
         value = 1; /* value should still be set to 1 */
-        setsockopt(eee->sock, SOL_TCP, TCP_NODELAY, &value, sizeof(value));
-#if !defined(WIN32) && !defined(__APPLE__)
+        setsockopt(eee->sock, IPPROTO_TCP, TCP_NODELAY, &value, sizeof(value));
+#ifdef LINUX
         value = 0;
-        setsockopt(eee->sock, SOL_TCP, TCP_CORK, &value, sizeof(value));
+        setsockopt(eee->sock, IPPROTO_TCP, TCP_CORK, &value, sizeof(value));
 #endif
     }
 

src/sn_utils.c

@@ -149,10 +149,10 @@ static ssize_t sendto_sock(n2n_sn_t *sss,
     // if the connection is tcp, i.e. not the regular sock...
     if((socket_fd >= 0) && (socket_fd != sss->sock)) {
 
-        setsockopt(socket_fd, SOL_TCP, TCP_NODELAY, &value, sizeof(value));
+        setsockopt(socket_fd, IPPROTO_TCP, TCP_NODELAY, &value, sizeof(value));
         value = 1;
-#if !defined(WIN32) && !defined(__APPLE__)
-        setsockopt(socket_fd, SOL_TCP, TCP_CORK, &value, sizeof(value));
+#ifdef LINUX
+        setsockopt(socket_fd, IPPROTO_TCP, TCP_CORK, &value, sizeof(value));
 #endif
 
         // prepend packet length...
@@ -169,10 +169,10 @@ static ssize_t sendto_sock(n2n_sn_t *sss,
     // if the connection is tcp, i.e. not the regular sock...
     if((socket_fd >= 0) && (socket_fd != sss->sock)) {
         value = 1; /* value should still be set to 1 */
-        setsockopt(socket_fd, SOL_TCP, TCP_NODELAY, &value, sizeof(value));
-#if !defined(WIN32) && !defined(__APPLE__)
+        setsockopt(socket_fd, IPPROTO_TCP, TCP_NODELAY, &value, sizeof(value));
+#ifdef LINUX
         value = 0;
-        setsockopt(socket_fd, SOL_TCP, TCP_CORK, &value, sizeof(value));
+        setsockopt(socket_fd, IPPROTO_TCP, TCP_CORK, &value, sizeof(value));
 #endif
     }