From a326463160669807197011436e65ca7789546e31 Mon Sep 17 00:00:00 2001
From: Matias Fontanini <matias.fontanini@gmail.com>
Date: Sun, 5 Apr 2015 11:53:12 -0700
Subject: [PATCH] Add one integer field for all flags on TCP.

---
 include/tins/tcp.h | 56 ++++++++++++++++++++++++++++------------------
 src/tcp.cpp        | 52 ++++++++++++++++--------------------------
 2 files changed, 53 insertions(+), 55 deletions(-)

diff --git a/include/tins/tcp.h b/include/tins/tcp.h
index c60f87a..877f501 100644
--- a/include/tins/tcp.h
+++ b/include/tins/tcp.h
@@ -507,6 +507,32 @@ namespace Tins {
             return new TCP(*this);
         }
     private:
+        #if TINS_IS_LITTLE_ENDIAN
+            TINS_BEGIN_PACK
+            struct flags_type {
+                uint8_t fin:1,
+                    syn:1,
+                    rst:1,
+                    psh:1,
+                    ack:1,
+                    urg:1,
+                    ece:1,
+                    cwr:1;
+            } TINS_END_PACK;
+        #else
+            TINS_BEGIN_PACK
+            struct flags_type {
+                uint8_t cwr:1,
+                    ece:1,
+                    urg:1,
+                    ack:1,
+                    psh:1,
+                    rst:1,
+                    syn:1,
+                    fin:1;
+            } TINS_END_PACK;
+        #endif
+
         TINS_BEGIN_PACK
         struct tcphdr {
             uint16_t sport;
@@ -514,30 +540,16 @@ namespace Tins {
             uint32_t seq;
             uint32_t ack_seq;
         #if TINS_IS_LITTLE_ENDIAN
-            uint16_t res1:4,
-                doff:4,
-                fin:1,
-                syn:1,
-                rst:1,
-                psh:1,
-                ack:1,
-                urg:1,
-                ece:1,
-                cwr:1;
-        #elif TINS_IS_BIG_ENDIAN
-            uint16_t doff:4,
-                res1:4,
-                cwr:1,
-                ece:1,
-                urg:1,
-                ack:1,
-                psh:1,
-                rst:1,
-                syn:1,
-                fin:1;
+            uint8_t res1:4,
+                doff:4;
         #else
-        #error	"Endian is not LE nor BE..."
+            uint8_t doff:4,
+                res1:4;
         #endif
+            union {
+                flags_type flags;
+                uint8_t flags_8;
+            };
             uint16_t	window;
             uint16_t	check;
             uint16_t	urg_ptr;
diff --git a/src/tcp.cpp b/src/tcp.cpp
index 9a3d8b0..3a9065b 100644
--- a/src/tcp.cpp
+++ b/src/tcp.cpp
@@ -200,28 +200,28 @@ TCP::AltChecksums TCP::altchecksum() const {
 small_uint<1> TCP::get_flag(Flags tcp_flag) const {
     switch(tcp_flag) {
         case FIN:
-            return _tcp.fin;
+            return _tcp.flags.fin;
             break;
         case SYN:
-            return _tcp.syn;
+            return _tcp.flags.syn;
             break;
         case RST:
-            return _tcp.rst;
+            return _tcp.flags.rst;
             break;
         case PSH:
-            return _tcp.psh;
+            return _tcp.flags.psh;
             break;
         case ACK:
-            return _tcp.ack;
+            return _tcp.flags.ack;
             break;
         case URG:
-            return _tcp.urg;
+            return _tcp.flags.urg;
             break;
         case ECE:
-            return _tcp.ece;
+            return _tcp.flags.ece;
             break;
         case CWR:
-            return _tcp.cwr;
+            return _tcp.flags.cwr;
             break;
         default:
             return 0;
@@ -230,55 +230,41 @@ small_uint<1> TCP::get_flag(Flags tcp_flag) const {
 }
 
 small_uint<12> TCP::flags() const {
-    return (_tcp.res1 << 8) |
-            (_tcp.cwr << 7) |
-            (_tcp.ece << 6) |
-            (_tcp.urg << 5) |
-            (_tcp.ack << 4) |
-            (_tcp.psh << 3) |
-            (_tcp.rst << 2) |
-            (_tcp.syn << 1) |
-            _tcp.fin;
+    return (_tcp.res1 << 8) | _tcp.flags_8;
 }
 
 void TCP::set_flag(Flags tcp_flag, small_uint<1> value) {
     switch(tcp_flag) {
         case FIN:
-            _tcp.fin = value;
+            _tcp.flags.fin = value;
             break;
         case SYN:
-            _tcp.syn = value;
+            _tcp.flags.syn = value;
             break;
         case RST:
-            _tcp.rst = value;
+            _tcp.flags.rst = value;
             break;
         case PSH:
-            _tcp.psh = value;
+            _tcp.flags.psh = value;
             break;
         case ACK:
-            _tcp.ack = value;
+            _tcp.flags.ack = value;
             break;
         case URG:
-            _tcp.urg = value;
+            _tcp.flags.urg = value;
             break;
         case ECE:
-            _tcp.ece = value;
+            _tcp.flags.ece = value;
             break;
         case CWR:
-            _tcp.cwr = value;
+            _tcp.flags.cwr = value;
             break;
     };
 }
 
 void TCP::flags(small_uint<12> value) {
-    _tcp.fin = (value & FIN) ? 1 : 0;
-    _tcp.syn = (value & SYN) ? 1 : 0;
-    _tcp.rst = (value & RST) ? 1 : 0;
-    _tcp.psh = (value & PSH) ? 1 : 0;
-    _tcp.ack = (value & ACK) ? 1 : 0;
-    _tcp.urg = (value & URG) ? 1 : 0;
-    _tcp.ece = (value & ECE) ? 1 : 0;
-    _tcp.cwr = (value & CWR) ? 1 : 0;
+    _tcp.res1 = (value >> 8) & 0x0f;
+    _tcp.flags_8 = value & 0xff;
 }
 
 void TCP::add_option(const option &opt) {