6 #include "rpc_protocol.h"
7 #include "thread_pool.h"
9 #include "marshall_wrap.h"
10 #include "connection.h"
11 #include "threaded_log.h"
13 using std::chrono::milliseconds;
16 static constexpr milliseconds to_max{12000};
17 static constexpr milliseconds to_min{100};
20 template<class P, class R, class ...Args>
21 struct is_valid_call : false_type {};
23 template<class S, class R, class ...Args>
24 struct is_valid_call<S(R &, Args...), R, Args...> : true_type {};
26 template<class P, class F>
27 struct is_valid_registration : false_type {};
29 template<class S, class R, class ...Args>
30 struct is_valid_registration<
31 S(R &, typename std::decay<Args>::type...),
32 S(R &, Args...)> : true_type {};
34 template<class P, class C, class S, class R, class ...Args>
35 struct is_valid_registration<
37 S(C::*)(R &, Args...)> : is_valid_registration<P, S(R &, Args...)> {};
39 // rpc client endpoint.
40 // manages a xid space per destination socket
41 // threaded: multiple threads can be sending RPCs,
42 class rpcc : private connection_delegate {
44 using proc_id_t = rpc_protocol::proc_id_t;
45 using nonce_t = rpc_protocol::nonce_t;
46 using xid_t = rpc_protocol::xid_t;
48 // manages per rpc info
50 caller(xid_t _xid, string *_rep) : xid(_xid), rep(_rep) {}
60 void get_latest_connection(shared_ptr<connection> & ch);
61 void update_xid_rep(xid_t xid, lock & m_lock);
66 nonce_t srv_nonce_ = 0;
67 bool bind_done_ = false;
69 bool reachable_ = true;
71 shared_ptr<connection> chan_;
73 std::mutex m_; // protect insert/delete to calls[]
75 std::mutex bind_m_; // protect bind operations
77 bool destroy_wait_ = false;
80 std::map<int, caller *> calls_;
82 // xid starts with 1 and latest received reply starts with 0
84 std::list<xid_t> xid_rep_window_ = {0};
87 void clear() { buf.clear(); xid = -1; }
88 bool isvalid() { return xid != -1; }
93 int xid_rep_done_ = -1;
95 int call_marshalled(const rpc_protocol::proc_t & proc, milliseconds to, string & rep, const marshall & req);
97 bool got_pdu(const shared_ptr<connection> & c, const string & b);
101 rpcc(const string & d);
104 int bind(milliseconds to = rpc::to_max);
106 // Manages a cache of RPC connections. Usage:
107 // if (auto cl = rpcc::bind_cached(dst))
108 // ret = cl->call(...);
109 // where the string dst has the form "host:port". Because bind_cached()
110 // may block, callers should probably not hold mutexes.
111 static shared_ptr<rpcc> bind_cached(const string & destination);
112 static void unbind_cached(const string & destination);
114 void set_reachable(bool r) { reachable_ = r; }
116 void cancel(lock & m_lock);
118 template<class P, class R, typename ...Args>
119 inline int call(const rpc_protocol::proc_checked_t<P> & proc, R & r, const Args & ... args) {
120 return call_timeout(proc, rpc::to_max, r, args...);
123 template<class P, class R, typename ...Args>
124 inline int call_timeout(const rpc_protocol::proc_checked_t<P> & proc, milliseconds to, R & r, const Args & ... args) {
125 static_assert(is_valid_call<P, R, Args...>::value, "RPC called with incorrect argument types");
127 int intret = call_marshalled(proc, to, rep, marshall(args...));
129 VERIFY(unmarshall(rep, true, r).okdone()); // guaranteed by static type checking
135 // rpc server endpoint.
136 class rpcs : private connection_delegate {
138 using proc_id_t = rpc_protocol::proc_id_t;
139 using nonce_t = rpc_protocol::nonce_t;
140 using xid_t = rpc_protocol::xid_t;
143 NEW, // new RPC, not a duplicate
144 INPROGRESS, // duplicate of an RPC we're still processing
145 DONE, // duplicate of an RPC we already replied to (have reply)
146 FORGOTTEN, // duplicate of an old RPC whose reply we've forgotten
149 // state about an in-progress or completed RPC, for at-most-once.
150 // if cb_present is true, then the RPC is complete and a reply
151 // has been sent; in that case buf points to a copy of the reply,
152 // and sz holds the size of the reply.
154 reply_t (xid_t _xid) : xid(_xid), cb_present(false) {}
155 reply_t (xid_t _xid, const string & _buf) : xid(_xid), cb_present(true), buf(_buf) {}
157 bool cb_present; // whether the reply buffer is valid
158 string buf; // the reply buffer
164 // provide at most once semantics by maintaining a window of replies
165 // per client that that client hasn't acknowledged receiving yet.
166 // indexed by client nonce.
167 std::map<nonce_t, std::list<reply_t>> reply_window_;
169 void add_reply(nonce_t clt_nonce, xid_t xid, const string & b);
171 rpcstate_t check_duplicate_and_update(nonce_t clt_nonce, xid_t xid,
172 xid_t rep_xid, string & b);
174 // latest connection to the client
175 std::map<nonce_t, shared_ptr<connection>> conns_;
177 bool reachable_ = true;
179 // map proc # to function
180 std::map<proc_id_t, handler *> procs_;
182 std::mutex procs_m_; // protect insert/delete to procs[]
183 std::mutex reply_window_m_; // protect reply window et al
184 std::mutex conns_m_; // protect conns_
186 void dispatch(shared_ptr<connection> c, const string & buf);
188 unique_ptr<thread_pool> dispatchpool_{new thread_pool(6)};
189 unique_ptr<connection_listener> listener_;
191 // RPC handler for clients binding
192 rpc_protocol::status rpcbind(nonce_t & r);
194 bool got_pdu(const shared_ptr<connection> & c, const string & b);
198 rpcs(in_port_t port);
201 void set_reachable(bool r) { reachable_ = r; }
203 template<class P, class F, class C=void>
204 inline void reg(const rpc_protocol::proc_checked_t<P> & proc, F f, C *c=nullptr) {
205 static_assert(is_valid_registration<P, F>::value, "RPC handler registered with incorrect argument types");
206 struct ReturnOnFailure {
207 static inline int unmarshall_args_failure() {
208 return rpc_protocol::unmarshall_args_failure;
212 VERIFY(procs_.count(proc.id) == 0);
213 procs_[proc.id] = marshalled_func<F, ReturnOnFailure>::wrap(f, c);
214 VERIFY(procs_.count(proc.id) >= 1);