Changes in the protocol:

1. Use absolute time and not relative - prevents accuracy reduction
2. Changed timeouts to 64 bit to prevent year 2038 problem

private/tcp_cache_protocol.h

@@ -44,26 +44,26 @@ namespace impl {
 				uint32_t trigger_len;
 			} rise;
 			struct {
+				int64_t timeout;
 				uint32_t key_len;
 				uint32_t data_len;
 				uint32_t triggers_len;
-				uint32_t timeout;
 			} store;
 			struct {
 				uint64_t generation;
+				int64_t timeout;
 				uint32_t data_len;
 				uint32_t triggers_len;
-				uint32_t timeout;
 			} data;
 			struct {
 				uint32_t keys;
 				uint32_t triggers;
 			} out_stats;
 			struct {
-				uint32_t timeout;
+				int64_t timeout;
 			} session_save;
 			struct {
-				uint32_t timeout;
+				int64_t timeout;
 			} session_data;
 		} operations;
 	};

src/session_tcp_storage.cpp

@@ -33,7 +33,7 @@ void tcp_storage::save(std::string const &sid,time_t timeout,std::string const &
 	tcp_operation_header h=tcp_operation_header();
 	h.opcode=opcodes::session_save;
 	h.size=in.size() + 32;
-	h.operations.session_save.timeout=timeout - time(0);
+	h.operations.session_save.timeout=timeout;
 	std::string data;
 	data.reserve(sid.size() + in.size());
 	data+=sid;
@@ -49,7 +49,7 @@ bool tcp_storage::load(std::string const &sid,time_t &timeout,std::string &out)
 	std::string data=sid;
 	tcp().get(sid).transmit(h,data);
 	if(h.opcode==opcodes::session_load_data) {
-		timeout = time(NULL) + h.operations.session_data.timeout;
+		timeout = h.operations.session_data.timeout;
 		out.swap(data);
 		return true;
 	}

src/tcp_cache_client.cpp

@@ -67,7 +67,7 @@ int tcp_cache::fetch(	std::string const &key,
 	if(h.opcode!=opcodes::data)
 		return not_found;
 
-	timeout = h.operations.data.timeout + time(0);
+	timeout = h.operations.data.timeout;
 	
 	generation=h.operations.data.generation;
 
@@ -115,9 +115,7 @@ void tcp_cache::store(	std::string const &key,
 	h.operations.store.key_len=key.size();
 	data.append(a);
 	h.operations.store.data_len=a.size();
-	time_t now;
-	time(&now);
-	h.operations.store.timeout=timeout-now > 0 ? timeout-now : 0;
+	h.operations.store.timeout=timeout;
 	unsigned tlen=0;
 	for(std::set<std::string>::const_iterator p=triggers.begin(),e=triggers.end();p!=e;++p) {
 		tlen+=p->size()+1;

src/tcp_cache_server.cpp

@@ -122,8 +122,7 @@ public:
 		hout_.size=data_out_.size();
 		
 		hout_.operations.data.generation=generation;
-		time_t now=time(0);
-		hout_.operations.data.timeout = timeout > now ? timeout - now : 0;
+		hout_.operations.data.timeout = timeout;
 	}
 
 	void rise()
@@ -184,7 +183,7 @@ public:
 			hout_.opcode=opcodes::error;
 			return;
 		}
-		time_t timeout=time(0)+(time_t)hin_.operations.store.timeout;
+		time_t timeout=hin_.operations.store.timeout;
 		std::string key;
 		key.assign(data_in_.begin(),data_in_.begin()+hin_.operations.store.key_len);
 		std::string data;
@@ -200,7 +199,7 @@ public:
 			hout_.opcode=opcodes::error;
 			return;
 		}
-		time_t timeout=hin_.operations.session_save.timeout + time(NULL);
+		time_t timeout=hin_.operations.session_save.timeout;
 		std::string sid(data_in_.begin(),data_in_.begin()+32);
 		std::string value(data_in_.begin()+32,data_in_.end());
 		sessions_->save(sid,timeout,value);
@@ -215,7 +214,7 @@ public:
 		time_t timeout;
 		int toffset;
 		std::string sid(data_in_.begin(),data_in_.end());
-		if(!sessions_->load(sid,timeout,data_out_) || (toffset=(timeout-time(NULL))) < 0) {
+		if(!sessions_->load(sid,timeout,data_out_) || (toffset=(timeout)) < 0) {
 			hout_.opcode=opcodes::no_data;
 			return;
 		}