FD.io VPP  v17.07.01-10-g3be13f0
Vector Packet Processing
input.c
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1 /*
2  * Copyright (c) 2015 Cisco and/or its affiliates.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at:
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 /*
16  * input.c: Unix file input
17  *
18  * Copyright (c) 2008 Eliot Dresselhaus
19  *
20  * Permission is hereby granted, free of charge, to any person obtaining
21  * a copy of this software and associated documentation files (the
22  * "Software"), to deal in the Software without restriction, including
23  * without limitation the rights to use, copy, modify, merge, publish,
24  * distribute, sublicense, and/or sell copies of the Software, and to
25  * permit persons to whom the Software is furnished to do so, subject to
26  * the following conditions:
27  *
28  * The above copyright notice and this permission notice shall be
29  * included in all copies or substantial portions of the Software.
30  *
31  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
32  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
33  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
34  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
35  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
36  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
37  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
38  */
39 
40 #include <vlib/vlib.h>
41 #include <vlib/unix/unix.h>
42 #include <signal.h>
43 
44 /* FIXME autoconf */
45 #define HAVE_LINUX_EPOLL
46 
47 #ifdef HAVE_LINUX_EPOLL
48 
49 #include <sys/epoll.h>
50 
51 typedef struct
52 {
53  int epoll_fd;
54  struct epoll_event *epoll_events;
55 
56  /* Statistics. */
60 
62 
63 static void
65 {
66  unix_main_t *um = &unix_main;
68  struct epoll_event e;
69  int op;
70 
71  memset (&e, 0, sizeof (e));
72 
73  e.events = EPOLLIN;
75  e.events |= EPOLLOUT;
77  e.events |= EPOLLET;
78  e.data.u32 = f - um->file_pool;
79 
80  op = -1;
81 
82  switch (update_type)
83  {
85  op = EPOLL_CTL_ADD;
86  break;
87 
89  op = EPOLL_CTL_MOD;
90  break;
91 
93  op = EPOLL_CTL_DEL;
94  break;
95 
96  default:
97  clib_warning ("unknown update_type %d", update_type);
98  return;
99  }
100 
101  if (epoll_ctl (em->epoll_fd, op, f->file_descriptor, &e) < 0)
102  clib_unix_warning ("epoll_ctl");
103 }
104 
105 static uword
107  vlib_node_runtime_t * node, vlib_frame_t * frame)
108 {
109  unix_main_t *um = &unix_main;
111  struct epoll_event *e;
112  int n_fds_ready;
113 
114  {
115  vlib_node_main_t *nm = &vm->node_main;
117  f64 timeout;
118  int timeout_ms, max_timeout_ms = 10;
119  f64 vector_rate = vlib_last_vectors_per_main_loop (vm);
120 
121  if (t == ~0ULL)
122  {
123  timeout = 10e-3;
124  timeout_ms = max_timeout_ms;
125  }
126  else
127  {
128  timeout =
129  (((i64) t - (i64) clib_cpu_time_now ())
131  /* subtract off some slop time */ - 50e-6;
132 
133  if (timeout < 1e-3)
134  {
135  /* We have event happenning in less than 1 ms so
136  don't allow epoll to wait */
137  timeout_ms = 0;
138  }
139  else
140  {
141  timeout_ms = timeout * 1e3;
142 
143  /* Must be between 1 and 10 ms. */
144  timeout_ms = clib_max (1, timeout_ms);
145  timeout_ms = clib_min (max_timeout_ms, timeout_ms);
146  }
147  }
148 
149  /* If we still have input nodes polling (e.g. vnet packet generator)
150  don't sleep. */
151  if (nm->input_node_counts_by_state[VLIB_NODE_STATE_POLLING] > 0)
152  timeout_ms = 0;
153 
154  /*
155  * When busy: don't wait & only epoll for input
156  * every 1024 times through main loop.
157  */
158  if (vector_rate > 1 || vm->api_queue_nonempty)
159  {
160  timeout_ms = 0;
161  node->input_main_loops_per_call = 1024;
162  }
163  else
164  /* We're not busy; go to sleep for a while. */
165  node->input_main_loops_per_call = 0;
166 
167  /* Allow any signal to wakeup our sleep. */
168  {
169  static sigset_t unblock_all_signals;
170  n_fds_ready = epoll_pwait (em->epoll_fd,
171  em->epoll_events,
172  vec_len (em->epoll_events),
173  timeout_ms, &unblock_all_signals);
174 
175  /* This kludge is necessary to run over absurdly old kernels */
176  if (n_fds_ready < 0 && errno == ENOSYS)
177  {
178  n_fds_ready = epoll_wait (em->epoll_fd,
179  em->epoll_events,
180  vec_len (em->epoll_events), timeout_ms);
181  }
182  }
183  }
184 
185  if (n_fds_ready < 0)
186  {
187  if (unix_error_is_fatal (errno))
188  vlib_panic_with_error (vm, clib_error_return_unix (0, "epoll_wait"));
189 
190  /* non fatal error (e.g. EINTR). */
191  return 0;
192  }
193 
194  em->epoll_waits += 1;
195  em->epoll_files_ready += n_fds_ready;
196 
197  for (e = em->epoll_events; e < em->epoll_events + n_fds_ready; e++)
198  {
199  u32 i = e->data.u32;
201  clib_error_t *errors[4];
202  int n_errors = 0;
203 
204  if (PREDICT_TRUE (!(e->events & EPOLLERR)))
205  {
206  if (e->events & EPOLLIN)
207  {
208  errors[n_errors] = f->read_function (f);
209  n_errors += errors[n_errors] != 0;
210  }
211  if (e->events & EPOLLOUT)
212  {
213  errors[n_errors] = f->write_function (f);
214  n_errors += errors[n_errors] != 0;
215  }
216  }
217  else
218  {
219  if (f->error_function)
220  {
221  errors[n_errors] = f->error_function (f);
222  n_errors += errors[n_errors] != 0;
223  }
224  else
225  close (f->file_descriptor);
226  }
227 
228  ASSERT (n_errors < ARRAY_LEN (errors));
229  for (i = 0; i < n_errors; i++)
230  {
231  unix_save_error (um, errors[i]);
232  }
233  }
234 
235  return 0;
236 }
237 
238 /* *INDENT-OFF* */
240  .function = linux_epoll_input,
241  .type = VLIB_NODE_TYPE_PRE_INPUT,
242  .name = "unix-epoll-input",
243 };
244 /* *INDENT-ON* */
245 
246 clib_error_t *
248 {
250  unix_main_t *um = &unix_main;
251 
252  /* Allocate some events. */
254 
255  em->epoll_fd = epoll_create (vec_len (em->epoll_events));
256  if (em->epoll_fd < 0)
257  return clib_error_return_unix (0, "epoll_create");
258 
260 
261  return 0;
262 }
263 
265 
266 #endif /* HAVE_LINUX_EPOLL */
267 
268 static clib_error_t *
270 {
272 }
273 
275 
276 /*
277  * fd.io coding-style-patch-verification: ON
278  *
279  * Local Variables:
280  * eval: (c-set-style "gnu")
281  * End:
282  */
unix_file_t * file_pool
Definition: unix.h:89
sll srl srl sll sra u16x4 i
Definition: vector_sse2.h:337
#define clib_min(x, y)
Definition: clib.h:332
static void vlib_panic_with_error(vlib_main_t *vm, clib_error_t *error)
Definition: main.h:237
u32 flags
Definition: unix.h:54
static clib_error_t * unix_input_init(vlib_main_t *vm)
Definition: input.c:269
static linux_epoll_main_t linux_epoll_main
Definition: input.c:61
unix_file_function_t * read_function
Definition: unix.h:62
static vlib_node_registration_t linux_epoll_input_node
(constructor) VLIB_REGISTER_NODE (linux_epoll_input_node)
Definition: input.c:239
#define PREDICT_TRUE(x)
Definition: clib.h:98
unix_main_t unix_main
Definition: main.c:60
u64 cpu_time_next_process_ready
Definition: node.h:675
static u64 clib_cpu_time_now(void)
Definition: time.h:73
clib_time_t clib_time
Definition: main.h:62
static u32 vlib_last_vectors_per_main_loop(vlib_main_t *vm)
Definition: main.h:265
u32 input_main_loops_per_call
For input nodes: decremented on each main loop interation until it reaches zero and function is calle...
Definition: node.h:443
#define VLIB_INIT_FUNCTION(x)
Definition: init.h:111
static uword linux_epoll_input(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
Definition: input.c:106
unsigned long u64
Definition: types.h:89
#define vec_resize(V, N)
Resize a vector (no header, unspecified alignment) Add N elements to end of given vector V...
Definition: vec.h:241
#define vlib_call_init_function(vm, x)
Definition: init.h:162
#define pool_elt_at_index(p, i)
Returns pointer to element at given index.
Definition: pool.h:397
u32 file_descriptor
Definition: unix.h:52
unix_file_function_t * error_function
Definition: unix.h:62
#define clib_error_return_unix(e, args...)
Definition: error.h:102
#define VLIB_FRAME_SIZE
Definition: node.h:329
f64 seconds_per_clock
Definition: time.h:57
long i64
Definition: types.h:82
#define UNIX_FILE_EVENT_EDGE_TRIGGERED
Definition: unix.h:56
static void linux_epoll_file_update(unix_file_t *f, unix_file_update_type_t update_type)
Definition: input.c:64
#define clib_warning(format, args...)
Definition: error.h:59
#define ARRAY_LEN(x)
Definition: clib.h:59
#define UNIX_FILE_DATA_AVAILABLE_TO_WRITE
Definition: unix.h:55
#define ASSERT(truth)
unsigned int u32
Definition: types.h:88
static word unix_error_is_fatal(word error)
Definition: error.h:118
clib_error_t * linux_epoll_input_init(vlib_main_t *vm)
Definition: input.c:247
unix_file_update_type_t
Definition: unix.h:71
#define clib_max(x, y)
Definition: clib.h:325
u64 uword
Definition: types.h:112
struct epoll_event * epoll_events
Definition: input.c:54
void(* file_update)(unix_file_t *file, unix_file_update_type_t update_type)
Definition: unix.h:94
unix_file_function_t * write_function
Definition: unix.h:62
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
double f64
Definition: types.h:142
u32 input_node_counts_by_state[VLIB_N_NODE_STATE]
Definition: node.h:691
vlib_node_main_t node_main
Definition: main.h:115
#define clib_unix_warning(format, args...)
Definition: error.h:68
Definition: unix.h:49
u64 epoll_files_ready
Definition: input.c:57
volatile u32 api_queue_nonempty
Definition: main.h:174
#define VLIB_REGISTER_NODE(x,...)
Definition: node.h:144
static void unix_save_error(unix_main_t *um, clib_error_t *error)
Definition: unix.h:177