. /include/boost/corosio /native /detail /posix /posix_resolver.hpp
100.00% Lines (2/2) 100.00% Functions (2/2)
[ ] prev/next file n p prev/next uncovered line
TLA Baseline Branch
Line Hits Code Line Hits Code
1   // 1   //
2   // Copyright (c) 2026 Steve Gerbino 2   // Copyright (c) 2026 Steve Gerbino
3   // 3   //
4   // Distributed under the Boost Software License, Version 1.0. (See accompanying 4   // Distributed under the Boost Software License, Version 1.0. (See accompanying
5   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 5   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6   // 6   //
7   // Official repository: https://github.com/cppalliance/corosio 7   // Official repository: https://github.com/cppalliance/corosio
8   // 8   //
9   9  
10   #ifndef BOOST_COROSIO_NATIVE_DETAIL_POSIX_POSIX_RESOLVER_HPP 10   #ifndef BOOST_COROSIO_NATIVE_DETAIL_POSIX_POSIX_RESOLVER_HPP
11   #define BOOST_COROSIO_NATIVE_DETAIL_POSIX_POSIX_RESOLVER_HPP 11   #define BOOST_COROSIO_NATIVE_DETAIL_POSIX_POSIX_RESOLVER_HPP
12   12  
13   #include <boost/corosio/detail/platform.hpp> 13   #include <boost/corosio/detail/platform.hpp>
14   14  
15   #if BOOST_COROSIO_POSIX 15   #if BOOST_COROSIO_POSIX
16   16  
17   #include <boost/corosio/detail/config.hpp> 17   #include <boost/corosio/detail/config.hpp>
18   #include <boost/corosio/resolver.hpp> 18   #include <boost/corosio/resolver.hpp>
19   #include <boost/capy/ex/execution_context.hpp> 19   #include <boost/capy/ex/execution_context.hpp>
20   20  
21   #include <boost/corosio/native/detail/endpoint_convert.hpp> 21   #include <boost/corosio/native/detail/endpoint_convert.hpp>
22   #include <boost/corosio/detail/intrusive.hpp> 22   #include <boost/corosio/detail/intrusive.hpp>
23   #include <boost/corosio/detail/dispatch_coro.hpp> 23   #include <boost/corosio/detail/dispatch_coro.hpp>
24   #include <boost/corosio/detail/scheduler_op.hpp> 24   #include <boost/corosio/detail/scheduler_op.hpp>
25   #include <boost/corosio/detail/thread_pool.hpp> 25   #include <boost/corosio/detail/thread_pool.hpp>
26   #include <boost/corosio/native/detail/coro_op.hpp> 26   #include <boost/corosio/native/detail/coro_op.hpp>
27   27  
28   #include <boost/corosio/detail/scheduler.hpp> 28   #include <boost/corosio/detail/scheduler.hpp>
29   #include <boost/capy/ex/executor_ref.hpp> 29   #include <boost/capy/ex/executor_ref.hpp>
30   #include <coroutine> 30   #include <coroutine>
31   #include <boost/capy/error.hpp> 31   #include <boost/capy/error.hpp>
32   32  
33   #include <netdb.h> 33   #include <netdb.h>
34   #include <netinet/in.h> 34   #include <netinet/in.h>
35   #include <sys/socket.h> 35   #include <sys/socket.h>
36   36  
37   #include <atomic> 37   #include <atomic>
38   #include <memory> 38   #include <memory>
39   #include <optional> 39   #include <optional>
40   #include <stop_token> 40   #include <stop_token>
41   #include <string> 41   #include <string>
42   42  
43   /* 43   /*
44   POSIX Resolver Service 44   POSIX Resolver Service
45   ====================== 45   ======================
46   46  
47   POSIX getaddrinfo() is a blocking call that cannot be monitored with 47   POSIX getaddrinfo() is a blocking call that cannot be monitored with
48   epoll/kqueue/io_uring. Blocking calls are dispatched to a shared 48   epoll/kqueue/io_uring. Blocking calls are dispatched to a shared
49   resolver_thread_pool service which reuses threads across operations. 49   resolver_thread_pool service which reuses threads across operations.
50   50  
51   Cancellation 51   Cancellation
52   ------------ 52   ------------
53   getaddrinfo() cannot be interrupted mid-call. We use an atomic flag to 53   getaddrinfo() cannot be interrupted mid-call. We use an atomic flag to
54   indicate cancellation was requested. The worker thread checks this flag 54   indicate cancellation was requested. The worker thread checks this flag
55   after getaddrinfo() returns and reports the appropriate error. 55   after getaddrinfo() returns and reports the appropriate error.
56   56  
57   Class Hierarchy 57   Class Hierarchy
58   --------------- 58   ---------------
59   - posix_resolver_service (execution_context service, one per context) 59   - posix_resolver_service (execution_context service, one per context)
60   - Owns all posix_resolver instances via shared_ptr 60   - Owns all posix_resolver instances via shared_ptr
61   - Stores scheduler* for posting completions 61   - Stores scheduler* for posting completions
62   - posix_resolver (one per resolver object) 62   - posix_resolver (one per resolver object)
63   - Contains embedded resolve_op and reverse_resolve_op for reuse 63   - Contains embedded resolve_op and reverse_resolve_op for reuse
64   - Uses shared_from_this to prevent premature destruction 64   - Uses shared_from_this to prevent premature destruction
65   - resolve_op (forward resolution state) 65   - resolve_op (forward resolution state)
66   - Uses getaddrinfo() to resolve host/service to endpoints 66   - Uses getaddrinfo() to resolve host/service to endpoints
67   - reverse_resolve_op (reverse resolution state) 67   - reverse_resolve_op (reverse resolution state)
68   - Uses getnameinfo() to resolve endpoint to host/service 68   - Uses getnameinfo() to resolve endpoint to host/service
69   69  
70   Completion Flow 70   Completion Flow
71   --------------- 71   ---------------
72   Forward resolution: 72   Forward resolution:
73   1. resolve() sets up op_, posts work to the thread pool 73   1. resolve() sets up op_, posts work to the thread pool
74   2. Pool thread runs getaddrinfo() (blocking) 74   2. Pool thread runs getaddrinfo() (blocking)
75   3. Pool thread stores results in op_.stored_results 75   3. Pool thread stores results in op_.stored_results
76   4. Pool thread calls svc_.post(&op_) to queue completion 76   4. Pool thread calls svc_.post(&op_) to queue completion
77   5. Scheduler invokes op_() which resumes the coroutine 77   5. Scheduler invokes op_() which resumes the coroutine
78   78  
79   Reverse resolution follows the same pattern using getnameinfo(). 79   Reverse resolution follows the same pattern using getnameinfo().
80   80  
81   Single-Inflight Constraint 81   Single-Inflight Constraint
82   -------------------------- 82   --------------------------
83   Each resolver has ONE embedded op_ for forward and ONE reverse_op_ for 83   Each resolver has ONE embedded op_ for forward and ONE reverse_op_ for
84   reverse resolution. Concurrent operations of the same type on the same 84   reverse resolution. Concurrent operations of the same type on the same
85   resolver would corrupt state. Users must serialize operations per-resolver. 85   resolver would corrupt state. Users must serialize operations per-resolver.
86   86  
87   Shutdown 87   Shutdown
88   -------- 88   --------
89   The resolver service cancels all resolvers and clears the impl map. 89   The resolver service cancels all resolvers and clears the impl map.
90   The thread pool service shuts down separately via execution_context 90   The thread pool service shuts down separately via execution_context
91   service ordering, joining all worker threads. 91   service ordering, joining all worker threads.
92   */ 92   */
93   93  
94   namespace boost::corosio::detail { 94   namespace boost::corosio::detail {
95   95  
96   struct scheduler; 96   struct scheduler;
97   97  
98   namespace posix_resolver_detail { 98   namespace posix_resolver_detail {
99   99  
100   // Convert resolve_flags to addrinfo ai_flags 100   // Convert resolve_flags to addrinfo ai_flags
101   int flags_to_hints(resolve_flags flags); 101   int flags_to_hints(resolve_flags flags);
102   102  
103   // Convert reverse_flags to getnameinfo NI_* flags 103   // Convert reverse_flags to getnameinfo NI_* flags
104   int flags_to_ni_flags(reverse_flags flags); 104   int flags_to_ni_flags(reverse_flags flags);
105   105  
106   // Convert addrinfo results to endpoints 106   // Convert addrinfo results to endpoints
107   std::vector<endpoint> convert_results(struct addrinfo* ai); 107   std::vector<endpoint> convert_results(struct addrinfo* ai);
108   108  
109   // Convert getaddrinfo error codes to std::error_code 109   // Convert getaddrinfo error codes to std::error_code
110   std::error_code make_gai_error(int gai_err); 110   std::error_code make_gai_error(int gai_err);
111   111  
112   } // namespace posix_resolver_detail 112   } // namespace posix_resolver_detail
113   113  
114   class posix_resolver_service; 114   class posix_resolver_service;
115   115  
116   /** Resolver implementation for POSIX backends. 116   /** Resolver implementation for POSIX backends.
117   117  
118   Each resolver instance contains a single embedded operation object (op_) 118   Each resolver instance contains a single embedded operation object (op_)
119   that is reused for each resolve() call. This design avoids per-operation 119   that is reused for each resolve() call. This design avoids per-operation
120   heap allocation but imposes a critical constraint: 120   heap allocation but imposes a critical constraint:
121   121  
122   @par Single-Inflight Contract 122   @par Single-Inflight Contract
123   123  
124   Only ONE resolve operation may be in progress at a time per resolver 124   Only ONE resolve operation may be in progress at a time per resolver
125   instance. Calling resolve() while a previous resolve() is still pending 125   instance. Calling resolve() while a previous resolve() is still pending
126   results in undefined behavior: 126   results in undefined behavior:
127   127  
128   - The new call overwrites op_ fields (host, service, coroutine handle) 128   - The new call overwrites op_ fields (host, service, coroutine handle)
129   - The worker thread from the first call reads corrupted state 129   - The worker thread from the first call reads corrupted state
130   - The wrong coroutine may be resumed, or resumed multiple times 130   - The wrong coroutine may be resumed, or resumed multiple times
131   - Data races occur on non-atomic op_ members 131   - Data races occur on non-atomic op_ members
132   132  
133   @par Safe Usage Patterns 133   @par Safe Usage Patterns
134   134  
135   @code 135   @code
136   // CORRECT: Sequential resolves 136   // CORRECT: Sequential resolves
137   auto [ec1, r1] = co_await resolver.resolve("host1", "80"); 137   auto [ec1, r1] = co_await resolver.resolve("host1", "80");
138   auto [ec2, r2] = co_await resolver.resolve("host2", "80"); 138   auto [ec2, r2] = co_await resolver.resolve("host2", "80");
139   139  
140   // CORRECT: Parallel resolves with separate resolver instances 140   // CORRECT: Parallel resolves with separate resolver instances
141   resolver r1(ctx), r2(ctx); 141   resolver r1(ctx), r2(ctx);
142   auto [ec1, res1] = co_await r1.resolve("host1", "80"); // in one coroutine 142   auto [ec1, res1] = co_await r1.resolve("host1", "80"); // in one coroutine
143   auto [ec2, res2] = co_await r2.resolve("host2", "80"); // in another 143   auto [ec2, res2] = co_await r2.resolve("host2", "80"); // in another
144   144  
145   // WRONG: Concurrent resolves on same resolver 145   // WRONG: Concurrent resolves on same resolver
146   // These may run concurrently if launched in parallel - UNDEFINED BEHAVIOR 146   // These may run concurrently if launched in parallel - UNDEFINED BEHAVIOR
147   auto f1 = resolver.resolve("host1", "80"); 147   auto f1 = resolver.resolve("host1", "80");
148   auto f2 = resolver.resolve("host2", "80"); // BAD: overlaps with f1 148   auto f2 = resolver.resolve("host2", "80"); // BAD: overlaps with f1
149   @endcode 149   @endcode
150   150  
151   @par Thread Safety 151   @par Thread Safety
152   Distinct objects: Safe. 152   Distinct objects: Safe.
153   Shared objects: Unsafe. See single-inflight contract above. 153   Shared objects: Unsafe. See single-inflight contract above.
154   */ 154   */
155   class posix_resolver final 155   class posix_resolver final
156   : public resolver::implementation 156   : public resolver::implementation
157   , public std::enable_shared_from_this<posix_resolver> 157   , public std::enable_shared_from_this<posix_resolver>
158   , public intrusive_list<posix_resolver>::node 158   , public intrusive_list<posix_resolver>::node
159   { 159   {
160   friend class posix_resolver_service; 160   friend class posix_resolver_service;
161   161  
162   public: 162   public:
163   // resolve_op - operation state for a single DNS resolution 163   // resolve_op - operation state for a single DNS resolution
164   164  
165   struct resolve_op : coro_op 165   struct resolve_op : coro_op
166   { 166   {
167   /// Where the endpoints are handed back. 167   /// Where the endpoints are handed back.
168   std::vector<endpoint>* out = nullptr; 168   std::vector<endpoint>* out = nullptr;
169   169  
170   // Input parameters (owned copies for thread safety) 170   // Input parameters (owned copies for thread safety)
171   std::string host; 171   std::string host;
172   std::string service; 172   std::string service;
173   resolve_flags flags = resolve_flags::none; 173   resolve_flags flags = resolve_flags::none;
174   174  
175   // Result storage (populated by worker thread) 175   // Result storage (populated by worker thread)
176   std::vector<endpoint> stored_results; 176   std::vector<endpoint> stored_results;
177   int gai_error = 0; 177   int gai_error = 0;
178   178  
HITCBC 179   64 resolve_op() = default; 179   64 resolve_op() = default;
180   180  
181   void reset() noexcept; 181   void reset() noexcept;
182   void operator()() override; 182   void operator()() override;
183   void destroy() override; 183   void destroy() override;
184   }; 184   };
185   185  
186   // reverse_resolve_op - operation state for reverse DNS resolution 186   // reverse_resolve_op - operation state for reverse DNS resolution
187   187  
188   struct reverse_resolve_op : coro_op 188   struct reverse_resolve_op : coro_op
189   { 189   {
190   /// Where the name is handed back. 190   /// Where the name is handed back.
191   endpoint_name* result_out = nullptr; 191   endpoint_name* result_out = nullptr;
192   192  
193   // Input parameters 193   // Input parameters
194   endpoint ep; 194   endpoint ep;
195   reverse_flags flags = reverse_flags::none; 195   reverse_flags flags = reverse_flags::none;
196   196  
197   // Result storage (populated by worker thread) 197   // Result storage (populated by worker thread)
198   std::string stored_host; 198   std::string stored_host;
199   std::string stored_service; 199   std::string stored_service;
200   int gai_error = 0; 200   int gai_error = 0;
201   201  
HITCBC 202   64 reverse_resolve_op() = default; 202   64 reverse_resolve_op() = default;
203   203  
204   void reset() noexcept; 204   void reset() noexcept;
205   void operator()() override; 205   void operator()() override;
206   void destroy() override; 206   void destroy() override;
207   }; 207   };
208   208  
209   /// Embedded pool work item for thread pool dispatch. 209   /// Embedded pool work item for thread pool dispatch.
210   struct pool_op : pool_work_item 210   struct pool_op : pool_work_item
211   { 211   {
212   /// Resolver that owns this work item. 212   /// Resolver that owns this work item.
213   posix_resolver* resolver_ = nullptr; 213   posix_resolver* resolver_ = nullptr;
214   214  
215   /// Prevent impl destruction while work is in flight. 215   /// Prevent impl destruction while work is in flight.
216   std::shared_ptr<posix_resolver> ref_; 216   std::shared_ptr<posix_resolver> ref_;
217   }; 217   };
218   218  
219   explicit posix_resolver(posix_resolver_service& svc) noexcept; 219   explicit posix_resolver(posix_resolver_service& svc) noexcept;
220   220  
221   std::coroutine_handle<> resolve( 221   std::coroutine_handle<> resolve(
222   std::coroutine_handle<>, 222   std::coroutine_handle<>,
223   capy::executor_ref, 223   capy::executor_ref,
224   std::string_view host, 224   std::string_view host,
225   std::string_view service, 225   std::string_view service,
226   resolve_flags flags, 226   resolve_flags flags,
227   std::stop_token, 227   std::stop_token,
228   std::error_code*, 228   std::error_code*,
229   std::vector<endpoint>*) override; 229   std::vector<endpoint>*) override;
230   230  
231   std::coroutine_handle<> reverse_resolve( 231   std::coroutine_handle<> reverse_resolve(
232   std::coroutine_handle<>, 232   std::coroutine_handle<>,
233   capy::executor_ref, 233   capy::executor_ref,
234   endpoint const& ep, 234   endpoint const& ep,
235   reverse_flags flags, 235   reverse_flags flags,
236   std::stop_token, 236   std::stop_token,
237   std::error_code*, 237   std::error_code*,
238   endpoint_name*) override; 238   endpoint_name*) override;
239   239  
240   void cancel() noexcept override; 240   void cancel() noexcept override;
241   241  
242   resolve_op op_; 242   resolve_op op_;
243   reverse_resolve_op reverse_op_; 243   reverse_resolve_op reverse_op_;
244   244  
245   /// Pool work item for forward resolution. 245   /// Pool work item for forward resolution.
246   pool_op resolve_pool_op_; 246   pool_op resolve_pool_op_;
247   247  
248   /// Pool work item for reverse resolution. 248   /// Pool work item for reverse resolution.
249   pool_op reverse_pool_op_; 249   pool_op reverse_pool_op_;
250   250  
251   /// Execute blocking `getaddrinfo()` on a pool thread. 251   /// Execute blocking `getaddrinfo()` on a pool thread.
252   static void do_resolve_work(pool_work_item*) noexcept; 252   static void do_resolve_work(pool_work_item*) noexcept;
253   253  
254   /// Execute blocking `getnameinfo()` on a pool thread. 254   /// Execute blocking `getnameinfo()` on a pool thread.
255   static void do_reverse_resolve_work(pool_work_item*) noexcept; 255   static void do_reverse_resolve_work(pool_work_item*) noexcept;
256   256  
257   private: 257   private:
258   posix_resolver_service& svc_; 258   posix_resolver_service& svc_;
259   }; 259   };
260   260  
261   } // namespace boost::corosio::detail 261   } // namespace boost::corosio::detail
262   262  
263   #endif // BOOST_COROSIO_POSIX 263   #endif // BOOST_COROSIO_POSIX
264   264  
265   #endif // BOOST_COROSIO_NATIVE_DETAIL_POSIX_POSIX_RESOLVER_HPP 265   #endif // BOOST_COROSIO_NATIVE_DETAIL_POSIX_POSIX_RESOLVER_HPP