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1 /*
2  *
3  * Copyright 2015 gRPC authors.
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  *     http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  *
17  */
18 
19 /* FIXME: "posix" files shouldn't be depending on _GNU_SOURCE */
20 #ifndef _GNU_SOURCE
21 #define _GNU_SOURCE
22 #endif
23 
24 #include <grpc/support/port_platform.h>
25 
26 #include "src/core/lib/iomgr/port.h"
27 
28 #ifdef GRPC_POSIX_SOCKET_TCP_SERVER
29 
30 #include <errno.h>
31 #include <fcntl.h>
32 #include <netinet/in.h>
33 #include <netinet/tcp.h>
34 #include <string.h>
35 #include <sys/socket.h>
36 #include <sys/stat.h>
37 #include <sys/types.h>
38 #include <unistd.h>
39 
40 #include <string>
41 
42 #include "absl/strings/str_cat.h"
43 #include "absl/strings/str_format.h"
44 
45 #include <grpc/support/alloc.h>
46 #include <grpc/support/log.h>
47 #include <grpc/support/sync.h>
48 #include <grpc/support/time.h>
49 
50 #include "src/core/lib/channel/channel_args.h"
51 #include "src/core/lib/gpr/string.h"
52 #include "src/core/lib/gprpp/memory.h"
53 #include "src/core/lib/iomgr/exec_ctx.h"
54 #include "src/core/lib/iomgr/resolve_address.h"
55 #include "src/core/lib/iomgr/sockaddr.h"
56 #include "src/core/lib/iomgr/sockaddr_utils.h"
57 #include "src/core/lib/iomgr/socket_utils_posix.h"
58 #include "src/core/lib/iomgr/tcp_posix.h"
59 #include "src/core/lib/iomgr/tcp_server.h"
60 #include "src/core/lib/iomgr/tcp_server_utils_posix.h"
61 #include "src/core/lib/iomgr/unix_sockets_posix.h"
62 
tcp_server_create(grpc_closure * shutdown_complete,const grpc_channel_args * args,grpc_tcp_server ** server)63 static grpc_error* tcp_server_create(grpc_closure* shutdown_complete,
64                                      const grpc_channel_args* args,
65                                      grpc_tcp_server** server) {
66   grpc_tcp_server* s =
67       static_cast<grpc_tcp_server*>(gpr_zalloc(sizeof(grpc_tcp_server)));
68   s->so_reuseport = grpc_is_socket_reuse_port_supported();
69   s->expand_wildcard_addrs = false;
70   for (size_t i = 0; i < (args == nullptr ? 0 : args->num_args); i++) {
71     if (0 == strcmp(GRPC_ARG_ALLOW_REUSEPORT, args->args[i].key)) {
72       if (args->args[i].type == GRPC_ARG_INTEGER) {
73         s->so_reuseport = grpc_is_socket_reuse_port_supported() &&
74                           (args->args[i].value.integer != 0);
75       } else {
76         gpr_free(s);
77         return GRPC_ERROR_CREATE_FROM_STATIC_STRING(GRPC_ARG_ALLOW_REUSEPORT
78                                                     " must be an integer");
79       }
80     } else if (0 == strcmp(GRPC_ARG_EXPAND_WILDCARD_ADDRS, args->args[i].key)) {
81       if (args->args[i].type == GRPC_ARG_INTEGER) {
82         s->expand_wildcard_addrs = (args->args[i].value.integer != 0);
83       } else {
84         gpr_free(s);
85         return GRPC_ERROR_CREATE_FROM_STATIC_STRING(
86             GRPC_ARG_EXPAND_WILDCARD_ADDRS " must be an integer");
87       }
88     }
89   }
90   gpr_ref_init(&s->refs, 1);
91   gpr_mu_init(&s->mu);
92   s->active_ports = 0;
93   s->destroyed_ports = 0;
94   s->shutdown = false;
95   s->shutdown_starting.head = nullptr;
96   s->shutdown_starting.tail = nullptr;
97   s->shutdown_complete = shutdown_complete;
98   s->on_accept_cb = nullptr;
99   s->on_accept_cb_arg = nullptr;
100   s->head = nullptr;
101   s->tail = nullptr;
102   s->nports = 0;
103   s->channel_args = grpc_channel_args_copy(args);
104   s->fd_handler = nullptr;
105   gpr_atm_no_barrier_store(&s->next_pollset_to_assign, 0);
106   *server = s;
107   return GRPC_ERROR_NONE;
108 }
109 
finish_shutdown(grpc_tcp_server * s)110 static void finish_shutdown(grpc_tcp_server* s) {
111   gpr_mu_lock(&s->mu);
112   GPR_ASSERT(s->shutdown);
113   gpr_mu_unlock(&s->mu);
114   if (s->shutdown_complete != nullptr) {
115     grpc_core::ExecCtx::Run(DEBUG_LOCATION, s->shutdown_complete,
116                             GRPC_ERROR_NONE);
117   }
118 
119   gpr_mu_destroy(&s->mu);
120 
121   while (s->head) {
122     grpc_tcp_listener* sp = s->head;
123     s->head = sp->next;
124     gpr_free(sp);
125   }
126   grpc_channel_args_destroy(s->channel_args);
127   delete s->fd_handler;
128 
129   gpr_free(s);
130 }
131 
destroyed_port(void * server,grpc_error *)132 static void destroyed_port(void* server, grpc_error* /*error*/) {
133   grpc_tcp_server* s = static_cast<grpc_tcp_server*>(server);
134   gpr_mu_lock(&s->mu);
135   s->destroyed_ports++;
136   if (s->destroyed_ports == s->nports) {
137     gpr_mu_unlock(&s->mu);
138     finish_shutdown(s);
139   } else {
140     GPR_ASSERT(s->destroyed_ports < s->nports);
141     gpr_mu_unlock(&s->mu);
142   }
143 }
144 
145 /* called when all listening endpoints have been shutdown, so no further
146    events will be received on them - at this point it's safe to destroy
147    things */
deactivated_all_ports(grpc_tcp_server * s)148 static void deactivated_all_ports(grpc_tcp_server* s) {
149   /* delete ALL the things */
150   gpr_mu_lock(&s->mu);
151 
152   GPR_ASSERT(s->shutdown);
153 
154   if (s->head) {
155     grpc_tcp_listener* sp;
156     for (sp = s->head; sp; sp = sp->next) {
157       grpc_unlink_if_unix_domain_socket(&sp->addr);
158       GRPC_CLOSURE_INIT(&sp->destroyed_closure, destroyed_port, s,
159                         grpc_schedule_on_exec_ctx);
160       grpc_fd_orphan(sp->emfd, &sp->destroyed_closure, nullptr,
161                      "tcp_listener_shutdown");
162     }
163     gpr_mu_unlock(&s->mu);
164   } else {
165     gpr_mu_unlock(&s->mu);
166     finish_shutdown(s);
167   }
168 }
169 
tcp_server_destroy(grpc_tcp_server * s)170 static void tcp_server_destroy(grpc_tcp_server* s) {
171   gpr_mu_lock(&s->mu);
172 
173   GPR_ASSERT(!s->shutdown);
174   s->shutdown = true;
175 
176   /* shutdown all fd's */
177   if (s->active_ports) {
178     grpc_tcp_listener* sp;
179     for (sp = s->head; sp; sp = sp->next) {
180       grpc_fd_shutdown(
181           sp->emfd, GRPC_ERROR_CREATE_FROM_STATIC_STRING("Server destroyed"));
182     }
183     gpr_mu_unlock(&s->mu);
184   } else {
185     gpr_mu_unlock(&s->mu);
186     deactivated_all_ports(s);
187   }
188 }
189 
190 /* event manager callback when reads are ready */
on_read(void * arg,grpc_error * err)191 static void on_read(void* arg, grpc_error* err) {
192   grpc_tcp_listener* sp = static_cast<grpc_tcp_listener*>(arg);
193   grpc_pollset* read_notifier_pollset;
194   if (err != GRPC_ERROR_NONE) {
195     goto error;
196   }
197 
198   /* loop until accept4 returns EAGAIN, and then re-arm notification */
199   for (;;) {
200     grpc_resolved_address addr;
201     memset(&addr, 0, sizeof(addr));
202     addr.len = static_cast<socklen_t>(sizeof(struct sockaddr_storage));
203     /* Note: If we ever decide to return this address to the user, remember to
204        strip off the ::ffff:0.0.0.0/96 prefix first. */
205     int fd = grpc_accept4(sp->fd, &addr, 1, 1);
206     if (fd < 0) {
207       switch (errno) {
208         case EINTR:
209           continue;
210         case EAGAIN:
211           grpc_fd_notify_on_read(sp->emfd, &sp->read_closure);
212           return;
213         default:
214           gpr_mu_lock(&sp->server->mu);
215           if (!sp->server->shutdown_listeners) {
216             gpr_log(GPR_ERROR, "Failed accept4: %s", strerror(errno));
217           } else {
218             /* if we have shutdown listeners, accept4 could fail, and we
219                needn't notify users */
220           }
221           gpr_mu_unlock(&sp->server->mu);
222           goto error;
223       }
224     }
225 
226     /* For UNIX sockets, the accept call might not fill up the member sun_path
227      * of sockaddr_un, so explicitly call getsockname to get it. */
228     if (grpc_is_unix_socket(&addr)) {
229       memset(&addr, 0, sizeof(addr));
230       addr.len = static_cast<socklen_t>(sizeof(struct sockaddr_storage));
231       if (getsockname(fd, reinterpret_cast<struct sockaddr*>(addr.addr),
232                       &(addr.len)) < 0) {
233         gpr_log(GPR_ERROR, "Failed getsockname: %s", strerror(errno));
234         close(fd);
235         goto error;
236       }
237     }
238 
239     grpc_set_socket_no_sigpipe_if_possible(fd);
240 
241     std::string addr_str = grpc_sockaddr_to_uri(&addr);
242     if (GRPC_TRACE_FLAG_ENABLED(grpc_tcp_trace)) {
243       gpr_log(GPR_INFO, "SERVER_CONNECT: incoming connection: %s",
244               addr_str.c_str());
245     }
246 
247     std::string name = absl::StrCat("tcp-server-connection:", addr_str);
248     grpc_fd* fdobj = grpc_fd_create(fd, name.c_str(), true);
249 
250     read_notifier_pollset = (*(sp->server->pollsets))
251         [static_cast<size_t>(gpr_atm_no_barrier_fetch_add(
252              &sp->server->next_pollset_to_assign, 1)) %
253          sp->server->pollsets->size()];
254 
255     grpc_pollset_add_fd(read_notifier_pollset, fdobj);
256 
257     // Create acceptor.
258     grpc_tcp_server_acceptor* acceptor =
259         static_cast<grpc_tcp_server_acceptor*>(gpr_malloc(sizeof(*acceptor)));
260     acceptor->from_server = sp->server;
261     acceptor->port_index = sp->port_index;
262     acceptor->fd_index = sp->fd_index;
263     acceptor->external_connection = false;
264 
265     sp->server->on_accept_cb(
266         sp->server->on_accept_cb_arg,
267         grpc_tcp_create(fdobj, sp->server->channel_args, addr_str.c_str()),
268         read_notifier_pollset, acceptor);
269   }
270 
271   GPR_UNREACHABLE_CODE(return );
272 
273 error:
274   gpr_mu_lock(&sp->server->mu);
275   if (0 == --sp->server->active_ports && sp->server->shutdown) {
276     gpr_mu_unlock(&sp->server->mu);
277     deactivated_all_ports(sp->server);
278   } else {
279     gpr_mu_unlock(&sp->server->mu);
280   }
281 }
282 
283 /* Treat :: or 0.0.0.0 as a family-agnostic wildcard. */
add_wildcard_addrs_to_server(grpc_tcp_server * s,unsigned port_index,int requested_port,int * out_port)284 static grpc_error* add_wildcard_addrs_to_server(grpc_tcp_server* s,
285                                                 unsigned port_index,
286                                                 int requested_port,
287                                                 int* out_port) {
288   grpc_resolved_address wild4;
289   grpc_resolved_address wild6;
290   unsigned fd_index = 0;
291   grpc_dualstack_mode dsmode;
292   grpc_tcp_listener* sp = nullptr;
293   grpc_tcp_listener* sp2 = nullptr;
294   grpc_error* v6_err = GRPC_ERROR_NONE;
295   grpc_error* v4_err = GRPC_ERROR_NONE;
296   *out_port = -1;
297 
298   if (grpc_tcp_server_have_ifaddrs() && s->expand_wildcard_addrs) {
299     return grpc_tcp_server_add_all_local_addrs(s, port_index, requested_port,
300                                                out_port);
301   }
302 
303   grpc_sockaddr_make_wildcards(requested_port, &wild4, &wild6);
304   /* Try listening on IPv6 first. */
305   if ((v6_err = grpc_tcp_server_add_addr(s, &wild6, port_index, fd_index,
306                                          &dsmode, &sp)) == GRPC_ERROR_NONE) {
307     ++fd_index;
308     requested_port = *out_port = sp->port;
309     if (dsmode == GRPC_DSMODE_DUALSTACK || dsmode == GRPC_DSMODE_IPV4) {
310       return GRPC_ERROR_NONE;
311     }
312   }
313   /* If we got a v6-only socket or nothing, try adding 0.0.0.0. */
314   grpc_sockaddr_set_port(&wild4, requested_port);
315   if ((v4_err = grpc_tcp_server_add_addr(s, &wild4, port_index, fd_index,
316                                          &dsmode, &sp2)) == GRPC_ERROR_NONE) {
317     *out_port = sp2->port;
318     if (sp != nullptr) {
319       sp2->is_sibling = 1;
320       sp->sibling = sp2;
321     }
322   }
323   if (*out_port > 0) {
324     if (v6_err != GRPC_ERROR_NONE) {
325       gpr_log(GPR_INFO,
326               "Failed to add :: listener, "
327               "the environment may not support IPv6: %s",
328               grpc_error_string(v6_err));
329       GRPC_ERROR_UNREF(v6_err);
330     }
331     if (v4_err != GRPC_ERROR_NONE) {
332       gpr_log(GPR_INFO,
333               "Failed to add 0.0.0.0 listener, "
334               "the environment may not support IPv4: %s",
335               grpc_error_string(v4_err));
336       GRPC_ERROR_UNREF(v4_err);
337     }
338     return GRPC_ERROR_NONE;
339   } else {
340     grpc_error* root_err = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
341         "Failed to add any wildcard listeners");
342     GPR_ASSERT(v6_err != GRPC_ERROR_NONE && v4_err != GRPC_ERROR_NONE);
343     root_err = grpc_error_add_child(root_err, v6_err);
344     root_err = grpc_error_add_child(root_err, v4_err);
345     return root_err;
346   }
347 }
348 
clone_port(grpc_tcp_listener * listener,unsigned count)349 static grpc_error* clone_port(grpc_tcp_listener* listener, unsigned count) {
350   grpc_tcp_listener* sp = nullptr;
351   std::string addr_str;
352   grpc_error* err;
353 
354   for (grpc_tcp_listener* l = listener->next; l && l->is_sibling; l = l->next) {
355     l->fd_index += count;
356   }
357 
358   for (unsigned i = 0; i < count; i++) {
359     int fd = -1;
360     int port = -1;
361     grpc_dualstack_mode dsmode;
362     err = grpc_create_dualstack_socket(&listener->addr, SOCK_STREAM, 0, &dsmode,
363                                        &fd);
364     if (err != GRPC_ERROR_NONE) return err;
365     err = grpc_tcp_server_prepare_socket(listener->server, fd, &listener->addr,
366                                          true, &port);
367     if (err != GRPC_ERROR_NONE) return err;
368     listener->server->nports++;
369     addr_str = grpc_sockaddr_to_string(&listener->addr, true);
370     sp = static_cast<grpc_tcp_listener*>(gpr_malloc(sizeof(grpc_tcp_listener)));
371     sp->next = listener->next;
372     listener->next = sp;
373     /* sp (the new listener) is a sibling of 'listener' (the original
374        listener). */
375     sp->is_sibling = 1;
376     sp->sibling = listener->sibling;
377     listener->sibling = sp;
378     sp->server = listener->server;
379     sp->fd = fd;
380     sp->emfd = grpc_fd_create(
381         fd,
382         absl::StrFormat("tcp-server-listener:%s/clone-%d", addr_str.c_str(), i)
383             .c_str(),
384         true);
385     memcpy(&sp->addr, &listener->addr, sizeof(grpc_resolved_address));
386     sp->port = port;
387     sp->port_index = listener->port_index;
388     sp->fd_index = listener->fd_index + count - i;
389     GPR_ASSERT(sp->emfd);
390     while (listener->server->tail->next != nullptr) {
391       listener->server->tail = listener->server->tail->next;
392     }
393   }
394 
395   return GRPC_ERROR_NONE;
396 }
397 
tcp_server_add_port(grpc_tcp_server * s,const grpc_resolved_address * addr,int * out_port)398 static grpc_error* tcp_server_add_port(grpc_tcp_server* s,
399                                        const grpc_resolved_address* addr,
400                                        int* out_port) {
401   grpc_tcp_listener* sp;
402   grpc_resolved_address sockname_temp;
403   grpc_resolved_address addr6_v4mapped;
404   int requested_port = grpc_sockaddr_get_port(addr);
405   unsigned port_index = 0;
406   grpc_dualstack_mode dsmode;
407   grpc_error* err;
408   *out_port = -1;
409   if (s->tail != nullptr) {
410     port_index = s->tail->port_index + 1;
411   }
412   grpc_unlink_if_unix_domain_socket(addr);
413 
414   /* Check if this is a wildcard port, and if so, try to keep the port the same
415      as some previously created listener. */
416   if (requested_port == 0) {
417     for (sp = s->head; sp; sp = sp->next) {
418       sockname_temp.len =
419           static_cast<socklen_t>(sizeof(struct sockaddr_storage));
420       if (0 ==
421           getsockname(sp->fd,
422                       reinterpret_cast<grpc_sockaddr*>(&sockname_temp.addr),
423                       &sockname_temp.len)) {
424         int used_port = grpc_sockaddr_get_port(&sockname_temp);
425         if (used_port > 0) {
426           memcpy(&sockname_temp, addr, sizeof(grpc_resolved_address));
427           grpc_sockaddr_set_port(&sockname_temp, used_port);
428           requested_port = used_port;
429           addr = &sockname_temp;
430           break;
431         }
432       }
433     }
434   }
435   if (grpc_sockaddr_is_wildcard(addr, &requested_port)) {
436     return add_wildcard_addrs_to_server(s, port_index, requested_port,
437                                         out_port);
438   }
439   if (grpc_sockaddr_to_v4mapped(addr, &addr6_v4mapped)) {
440     addr = &addr6_v4mapped;
441   }
442   if ((err = grpc_tcp_server_add_addr(s, addr, port_index, 0, &dsmode, &sp)) ==
443       GRPC_ERROR_NONE) {
444     *out_port = sp->port;
445   }
446   return err;
447 }
448 
449 /* Return listener at port_index or NULL. Should only be called with s->mu
450    locked. */
get_port_index(grpc_tcp_server * s,unsigned port_index)451 static grpc_tcp_listener* get_port_index(grpc_tcp_server* s,
452                                          unsigned port_index) {
453   unsigned num_ports = 0;
454   grpc_tcp_listener* sp;
455   for (sp = s->head; sp; sp = sp->next) {
456     if (!sp->is_sibling) {
457       if (++num_ports > port_index) {
458         return sp;
459       }
460     }
461   }
462   return nullptr;
463 }
464 
tcp_server_port_fd_count(grpc_tcp_server * s,unsigned port_index)465 unsigned tcp_server_port_fd_count(grpc_tcp_server* s, unsigned port_index) {
466   unsigned num_fds = 0;
467   gpr_mu_lock(&s->mu);
468   grpc_tcp_listener* sp = get_port_index(s, port_index);
469   for (; sp; sp = sp->sibling) {
470     ++num_fds;
471   }
472   gpr_mu_unlock(&s->mu);
473   return num_fds;
474 }
475 
tcp_server_port_fd(grpc_tcp_server * s,unsigned port_index,unsigned fd_index)476 static int tcp_server_port_fd(grpc_tcp_server* s, unsigned port_index,
477                               unsigned fd_index) {
478   gpr_mu_lock(&s->mu);
479   grpc_tcp_listener* sp = get_port_index(s, port_index);
480   for (; sp; sp = sp->sibling, --fd_index) {
481     if (fd_index == 0) {
482       gpr_mu_unlock(&s->mu);
483       return sp->fd;
484     }
485   }
486   gpr_mu_unlock(&s->mu);
487   return -1;
488 }
489 
tcp_server_start(grpc_tcp_server * s,const std::vector<grpc_pollset * > * pollsets,grpc_tcp_server_cb on_accept_cb,void * on_accept_cb_arg)490 static void tcp_server_start(grpc_tcp_server* s,
491                              const std::vector<grpc_pollset*>* pollsets,
492                              grpc_tcp_server_cb on_accept_cb,
493                              void* on_accept_cb_arg) {
494   size_t i;
495   grpc_tcp_listener* sp;
496   GPR_ASSERT(on_accept_cb);
497   gpr_mu_lock(&s->mu);
498   GPR_ASSERT(!s->on_accept_cb);
499   GPR_ASSERT(s->active_ports == 0);
500   s->on_accept_cb = on_accept_cb;
501   s->on_accept_cb_arg = on_accept_cb_arg;
502   s->pollsets = pollsets;
503   sp = s->head;
504   while (sp != nullptr) {
505     if (s->so_reuseport && !grpc_is_unix_socket(&sp->addr) &&
506         pollsets->size() > 1) {
507       GPR_ASSERT(GRPC_LOG_IF_ERROR(
508           "clone_port", clone_port(sp, (unsigned)(pollsets->size() - 1))));
509       for (i = 0; i < pollsets->size(); i++) {
510         grpc_pollset_add_fd((*pollsets)[i], sp->emfd);
511         GRPC_CLOSURE_INIT(&sp->read_closure, on_read, sp,
512                           grpc_schedule_on_exec_ctx);
513         grpc_fd_notify_on_read(sp->emfd, &sp->read_closure);
514         s->active_ports++;
515         sp = sp->next;
516       }
517     } else {
518       for (i = 0; i < pollsets->size(); i++) {
519         grpc_pollset_add_fd((*pollsets)[i], sp->emfd);
520       }
521       GRPC_CLOSURE_INIT(&sp->read_closure, on_read, sp,
522                         grpc_schedule_on_exec_ctx);
523       grpc_fd_notify_on_read(sp->emfd, &sp->read_closure);
524       s->active_ports++;
525       sp = sp->next;
526     }
527   }
528   gpr_mu_unlock(&s->mu);
529 }
530 
tcp_server_ref(grpc_tcp_server * s)531 grpc_tcp_server* tcp_server_ref(grpc_tcp_server* s) {
532   gpr_ref_non_zero(&s->refs);
533   return s;
534 }
535 
tcp_server_shutdown_starting_add(grpc_tcp_server * s,grpc_closure * shutdown_starting)536 static void tcp_server_shutdown_starting_add(grpc_tcp_server* s,
537                                              grpc_closure* shutdown_starting) {
538   gpr_mu_lock(&s->mu);
539   grpc_closure_list_append(&s->shutdown_starting, shutdown_starting,
540                            GRPC_ERROR_NONE);
541   gpr_mu_unlock(&s->mu);
542 }
543 
tcp_server_unref(grpc_tcp_server * s)544 static void tcp_server_unref(grpc_tcp_server* s) {
545   if (gpr_unref(&s->refs)) {
546     grpc_tcp_server_shutdown_listeners(s);
547     gpr_mu_lock(&s->mu);
548     grpc_core::ExecCtx::RunList(DEBUG_LOCATION, &s->shutdown_starting);
549     gpr_mu_unlock(&s->mu);
550     tcp_server_destroy(s);
551   }
552 }
553 
tcp_server_shutdown_listeners(grpc_tcp_server * s)554 static void tcp_server_shutdown_listeners(grpc_tcp_server* s) {
555   gpr_mu_lock(&s->mu);
556   s->shutdown_listeners = true;
557   /* shutdown all fd's */
558   if (s->active_ports) {
559     grpc_tcp_listener* sp;
560     for (sp = s->head; sp; sp = sp->next) {
561       grpc_fd_shutdown(sp->emfd,
562                        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Server shutdown"));
563     }
564   }
565   gpr_mu_unlock(&s->mu);
566 }
567 
568 namespace {
569 class ExternalConnectionHandler : public grpc_core::TcpServerFdHandler {
570  public:
ExternalConnectionHandler(grpc_tcp_server * s)571   explicit ExternalConnectionHandler(grpc_tcp_server* s) : s_(s) {}
572 
573   // TODO(yangg) resolve duplicate code with on_read
Handle(int listener_fd,int fd,grpc_byte_buffer * buf)574   void Handle(int listener_fd, int fd, grpc_byte_buffer* buf) override {
575     grpc_pollset* read_notifier_pollset;
576     grpc_resolved_address addr;
577     memset(&addr, 0, sizeof(addr));
578     addr.len = static_cast<socklen_t>(sizeof(struct sockaddr_storage));
579     grpc_core::ExecCtx exec_ctx;
580 
581     if (getpeername(fd, reinterpret_cast<struct sockaddr*>(addr.addr),
582                     &(addr.len)) < 0) {
583       gpr_log(GPR_ERROR, "Failed getpeername: %s", strerror(errno));
584       close(fd);
585       return;
586     }
587     grpc_set_socket_no_sigpipe_if_possible(fd);
588     std::string addr_str = grpc_sockaddr_to_uri(&addr);
589     if (grpc_tcp_trace.enabled()) {
590       gpr_log(GPR_INFO, "SERVER_CONNECT: incoming external connection: %s",
591               addr_str.c_str());
592     }
593     std::string name = absl::StrCat("tcp-server-connection:", addr_str);
594     grpc_fd* fdobj = grpc_fd_create(fd, name.c_str(), true);
595     read_notifier_pollset =
596         (*(s_->pollsets))[static_cast<size_t>(gpr_atm_no_barrier_fetch_add(
597                               &s_->next_pollset_to_assign, 1)) %
598                           s_->pollsets->size()];
599     grpc_pollset_add_fd(read_notifier_pollset, fdobj);
600     grpc_tcp_server_acceptor* acceptor =
601         static_cast<grpc_tcp_server_acceptor*>(gpr_malloc(sizeof(*acceptor)));
602     acceptor->from_server = s_;
603     acceptor->port_index = -1;
604     acceptor->fd_index = -1;
605     acceptor->external_connection = true;
606     acceptor->listener_fd = listener_fd;
607     acceptor->pending_data = buf;
608     s_->on_accept_cb(s_->on_accept_cb_arg,
609                      grpc_tcp_create(fdobj, s_->channel_args, addr_str.c_str()),
610                      read_notifier_pollset, acceptor);
611   }
612 
613  private:
614   grpc_tcp_server* s_;
615 };
616 }  // namespace
617 
tcp_server_create_fd_handler(grpc_tcp_server * s)618 static grpc_core::TcpServerFdHandler* tcp_server_create_fd_handler(
619     grpc_tcp_server* s) {
620   s->fd_handler = new ExternalConnectionHandler(s);
621   return s->fd_handler;
622 }
623 
624 grpc_tcp_server_vtable grpc_posix_tcp_server_vtable = {
625     tcp_server_create,        tcp_server_start,
626     tcp_server_add_port,      tcp_server_create_fd_handler,
627     tcp_server_port_fd_count, tcp_server_port_fd,
628     tcp_server_ref,           tcp_server_shutdown_starting_add,
629     tcp_server_unref,         tcp_server_shutdown_listeners};
630 
631 #endif /* GRPC_POSIX_SOCKET_TCP_SERVER */
632