2 * Copyright (c) 2017 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:
7 * http://www.apache.org/licenses/LICENSE-2.0
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.
16 * ioam_cache_tunnel_select_node.c
17 * This file implements anycast server selection using ioam data
18 * attached to anycast service selection.
19 * Anycast service is reachable via multiple servers reachable
21 * Works with TCP Anycast application.
22 * Cache entry is created when TCP SYN is received for anycast destination.
23 * Response TCP SYN ACKs for anycast service is compared and selected
24 * response is forwarded.
25 * The functionality is introduced via graph nodes that are hooked into
26 * vnet graph via classifier configs like below:
28 * Enable anycast service selection:
29 * set ioam ip6 sr-tunnel-select oneway
31 * Enable following classifier on the anycast service client facing interface
32 * e.g. anycast service is db06::06 then:
33 * classify session acl-hit-next ip6-node ip6-add-syn-hop-by-hop table-index 0 match l3
34 * ip6 dst db06::06 ioam-encap anycast
36 * Enable following classifier on the interfaces facing the server of anycast service:
37 * classify session acl-hit-next ip6-node ip6-lookup table-index 0 match l3
38 * ip6 src db06::06 ioam-decap anycast
41 #include <vlib/vlib.h>
42 #include <vnet/vnet.h>
43 #include <vppinfra/error.h>
44 #include <vnet/ip/ip.h>
45 #include <vnet/srv6/sr.h>
46 #include <ioam/ip6/ioam_cache.h>
47 #include <vnet/ip/ip6_hop_by_hop.h>
48 #include <vnet/ip/ip6_hop_by_hop_packet.h>
49 #include <vnet/ip/ip6_inlines.h>
57 /* packet trace format function */
59 format_cache_ts_trace (u8 * s, va_list * args)
61 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
62 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
63 cache_ts_trace_t *t = va_arg (*args, cache_ts_trace_t *);
65 s = format (s, "CACHE: flow_label %d, next index %d",
66 t->flow_label, t->next_index);
70 #define foreach_cache_ts_error \
71 _(RECORDED, "ip6 iOAM headers cached")
75 #define _(sym,str) CACHE_TS_ERROR_##sym,
76 foreach_cache_ts_error
81 static char *cache_ts_error_strings[] = {
82 #define _(sym,string) string,
83 foreach_cache_ts_error
89 IOAM_CACHE_TS_NEXT_POP_HBYH,
90 IOAM_CACHE_TS_ERROR_NEXT_DROP,
95 ip6_ioam_cache_ts_node_fn (vlib_main_t * vm,
96 vlib_node_runtime_t * node, vlib_frame_t * frame)
98 ioam_cache_main_t *cm = &ioam_cache_main;
99 u32 n_left_from, *from, *to_next;
100 cache_ts_next_t next_index;
103 from = vlib_frame_vector_args (frame);
104 n_left_from = frame->n_vectors;
105 next_index = node->cached_next_index;
107 while (n_left_from > 0)
111 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
113 while (n_left_from > 0 && n_left_to_next > 0)
117 u32 next0 = IOAM_CACHE_TS_NEXT_POP_HBYH;
119 ip6_hop_by_hop_header_t *hbh0, *hbh_cmp;
122 u32 cache_ts_index = 0;
123 u8 cache_thread_id = 0;
131 p0 = vlib_get_buffer (vm, bi0);
132 ip0 = vlib_buffer_get_current (p0);
133 if (IP_PROTOCOL_TCP ==
134 ip6_locate_header (p0, ip0, IP_PROTOCOL_TCP, &tcp_offset0))
136 tcp0 = (tcp_header_t *) ((u8 *) ip0 + tcp_offset0);
137 if ((tcp0->flags & TCP_FLAG_SYN) == TCP_FLAG_SYN &&
138 (tcp0->flags & TCP_FLAG_ACK) == TCP_FLAG_ACK)
140 /* Look up and compare */
141 hbh0 = (ip6_hop_by_hop_header_t *) (ip0 + 1);
143 if (0 == ioam_cache_ts_lookup (ip0,
150 (tcp0->ack_number), &hbh_cmp,
152 &cache_thread_id, 1))
158 ip6_ioam_analyse_compare_path_delay (hbh0, hbh_cmp,
159 cm->criteria_oneway);
162 /* current syn/ack is worse than the earlier: Drop */
163 next0 = IOAM_CACHE_TS_ERROR_NEXT_DROP;
164 /* Check if all responses are received or time has exceeded
165 send cached response if yes */
166 ioam_cache_ts_check_and_send (cache_thread_id,
171 /* Update cache with this buffer */
172 /* If successfully updated then skip sending it */
175 ioam_cache_ts_update (cache_thread_id,
182 next0 = IOAM_CACHE_TS_ERROR_NEXT_DROP;
187 next0 = IOAM_CACHE_TS_ERROR_NEXT_DROP;
190 else if ((tcp0->flags & TCP_FLAG_RST) == TCP_FLAG_RST)
192 /* Look up and compare */
193 hbh0 = (ip6_hop_by_hop_header_t *) (ip0 + 1);
194 if (0 == ioam_cache_ts_lookup (ip0, hbh0->protocol, clib_net_to_host_u16 (tcp0->src_port), clib_net_to_host_u16 (tcp0->dst_port), clib_net_to_host_u32 (tcp0->ack_number), &hbh_cmp, &cache_ts_index, &cache_thread_id, 1)) //response seen
196 next0 = IOAM_CACHE_TS_ERROR_NEXT_DROP;
198 ioam_cache_ts_check_and_send (cache_thread_id,
204 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
206 if (p0->flags & VLIB_BUFFER_IS_TRACED)
208 cache_ts_trace_t *t =
209 vlib_add_trace (vm, node, p0, sizeof (*t));
212 (ip0->ip_version_traffic_class_and_flow_label);
213 t->next_index = next0;
216 /* verify speculative enqueue, maybe switch current next frame */
222 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
223 to_next, n_left_to_next,
228 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
230 vlib_node_increment_counter (vm, ioam_cache_ts_node.index,
231 CACHE_TS_ERROR_RECORDED, recorded);
232 return frame->n_vectors;
236 * Node for IP6 iOAM header cache
238 VLIB_REGISTER_NODE (ioam_cache_ts_node) =
240 .function = ip6_ioam_cache_ts_node_fn,
241 .name = "ip6-ioam-tunnel-select",
242 .vector_size = sizeof (u32),
243 .format_trace = format_cache_ts_trace,
244 .type = VLIB_NODE_TYPE_INTERNAL,
245 .n_errors = ARRAY_LEN (cache_ts_error_strings),
246 .error_strings = cache_ts_error_strings,
247 .n_next_nodes = IOAM_CACHE_TS_N_NEXT,
248 /* edit / add dispositions here */
251 [IOAM_CACHE_TS_NEXT_POP_HBYH] = "ip6-pop-hop-by-hop",
252 [IOAM_CACHE_TS_ERROR_NEXT_DROP] = "error-drop",
259 } ip6_reset_ts_hbh_trace_t;
261 /* packet trace format function */
263 format_ip6_reset_ts_hbh_trace (u8 * s, va_list * args)
265 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
266 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
267 ip6_reset_ts_hbh_trace_t *t = va_arg (*args,
268 ip6_reset_ts_hbh_trace_t *);
271 format (s, "IP6_IOAM_RESET_TUNNEL_SELECT_HBH: next index %d",
276 #define foreach_ip6_reset_ts_hbh_error \
277 _(PROCESSED, "iOAM Syn/Ack Pkts processed") \
278 _(SAVED, "iOAM Syn Pkts state saved") \
279 _(REMOVED, "iOAM Syn/Ack Pkts state removed")
283 #define _(sym,str) IP6_RESET_TS_HBH_ERROR_##sym,
284 foreach_ip6_reset_ts_hbh_error
286 IP6_RESET_TS_HBH_N_ERROR,
287 } ip6_reset_ts_hbh_error_t;
289 static char *ip6_reset_ts_hbh_error_strings[] = {
290 #define _(sym,string) string,
291 foreach_ip6_reset_ts_hbh_error
295 #define foreach_ip6_ioam_cache_ts_input_next \
296 _(IP6_LOOKUP, "ip6-lookup") \
297 _(DROP, "error-drop")
301 #define _(s,n) IP6_IOAM_CACHE_TS_INPUT_NEXT_##s,
302 foreach_ip6_ioam_cache_ts_input_next
304 IP6_IOAM_CACHE_TS_INPUT_N_NEXT,
305 } ip6_ioam_cache_ts_input_next_t;
308 VLIB_NODE_FN (ip6_reset_ts_hbh_node) (vlib_main_t * vm,
309 vlib_node_runtime_t * node,
310 vlib_frame_t * frame)
312 ioam_cache_main_t *cm = &ioam_cache_main;
313 u32 n_left_from, *from, *to_next;
314 ip_lookup_next_t next_index;
315 u32 processed = 0, cache_ts_added = 0;
317 u8 *rewrite = cm->rewrite;
318 u32 rewrite_length = vec_len (rewrite);
319 ioam_e2e_cache_option_t *e2e = 0;
320 u8 no_of_responses = cm->wait_for_responses;
322 from = vlib_frame_vector_args (frame);
323 n_left_from = frame->n_vectors;
324 next_index = node->cached_next_index;
326 while (n_left_from > 0)
330 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
332 now = vlib_time_now (vm);
333 while (n_left_from >= 4 && n_left_to_next >= 2)
336 vlib_buffer_t *b0, *b1;
338 ip6_header_t *ip0, *ip1;
339 tcp_header_t *tcp0, *tcp1;
340 u32 tcp_offset0, tcp_offset1;
341 ip6_hop_by_hop_header_t *hbh0, *hbh1;
342 u64 *copy_src0, *copy_dst0, *copy_src1, *copy_dst1;
344 u32 pool_index0 = 0, pool_index1 = 0;
346 next0 = next1 = IP6_IOAM_CACHE_TS_INPUT_NEXT_IP6_LOOKUP;
347 /* Prefetch next iteration. */
349 vlib_buffer_t *p2, *p3;
351 p2 = vlib_get_buffer (vm, from[2]);
352 p3 = vlib_get_buffer (vm, from[3]);
354 vlib_prefetch_buffer_header (p2, LOAD);
355 vlib_prefetch_buffer_header (p3, LOAD);
356 CLIB_PREFETCH (p2->data, 2 * CLIB_CACHE_LINE_BYTES, LOAD);
357 CLIB_PREFETCH (p3->data, 2 * CLIB_CACHE_LINE_BYTES, LOAD);
361 /* speculatively enqueue b0 to the current next frame */
362 to_next[0] = bi0 = from[0];
363 to_next[1] = bi1 = from[1];
369 b0 = vlib_get_buffer (vm, bi0);
370 b1 = vlib_get_buffer (vm, bi1);
372 ip0 = vlib_buffer_get_current (b0);
373 ip1 = vlib_buffer_get_current (b1);
375 if (IP_PROTOCOL_TCP !=
376 ip6_locate_header (b0, ip0, IP_PROTOCOL_TCP, &tcp_offset0))
380 tcp0 = (tcp_header_t *) ((u8 *) ip0 + tcp_offset0);
381 if ((tcp0->flags & TCP_FLAG_SYN) == TCP_FLAG_SYN &&
382 (tcp0->flags & TCP_FLAG_ACK) == 0)
384 if (no_of_responses > 0)
386 /* Create TS select entry */
387 if (0 == ioam_cache_ts_add (ip0,
393 (tcp0->seq_number) + 1,
394 no_of_responses, now,
395 vm->thread_index, &pool_index0))
400 copy_dst0 = (u64 *) (((u8 *) ip0) - rewrite_length);
401 copy_src0 = (u64 *) ip0;
403 copy_dst0[0] = copy_src0[0];
404 copy_dst0[1] = copy_src0[1];
405 copy_dst0[2] = copy_src0[2];
406 copy_dst0[3] = copy_src0[3];
407 copy_dst0[4] = copy_src0[4];
409 vlib_buffer_advance (b0, -(word) rewrite_length);
410 ip0 = vlib_buffer_get_current (b0);
412 hbh0 = (ip6_hop_by_hop_header_t *) (ip0 + 1);
413 /* $$$ tune, rewrite_length is a multiple of 8 */
414 clib_memcpy_fast (hbh0, rewrite, rewrite_length);
416 (ioam_e2e_cache_option_t *) ((u8 *) hbh0 +
417 cm->rewrite_pool_index_offset);
418 e2e->pool_id = (u8) vm->thread_index;
419 e2e->pool_index = pool_index0;
420 ioam_e2e_id_rewrite_handler ((ioam_e2e_id_option_t *)
422 sizeof (ioam_e2e_cache_option_t)),
423 &cm->sr_localsid_ts);
424 /* Patch the protocol chain, insert the h-b-h (type 0) header */
425 hbh0->protocol = ip0->protocol;
428 clib_net_to_host_u16 (ip0->payload_length) + rewrite_length;
429 ip0->payload_length = clib_host_to_net_u16 (new_l0);
434 if (IP_PROTOCOL_TCP !=
435 ip6_locate_header (b1, ip1, IP_PROTOCOL_TCP, &tcp_offset1))
439 tcp1 = (tcp_header_t *) ((u8 *) ip1 + tcp_offset1);
440 if ((tcp1->flags & TCP_FLAG_SYN) == TCP_FLAG_SYN &&
441 (tcp1->flags & TCP_FLAG_ACK) == 0)
443 if (no_of_responses > 0)
445 /* Create TS select entry */
446 if (0 == ioam_cache_ts_add (ip1,
452 (tcp1->seq_number) + 1,
453 no_of_responses, now,
454 vm->thread_index, &pool_index1))
460 copy_dst1 = (u64 *) (((u8 *) ip1) - rewrite_length);
461 copy_src1 = (u64 *) ip1;
463 copy_dst1[0] = copy_src1[0];
464 copy_dst1[1] = copy_src1[1];
465 copy_dst1[2] = copy_src1[2];
466 copy_dst1[3] = copy_src1[3];
467 copy_dst1[4] = copy_src1[4];
469 vlib_buffer_advance (b1, -(word) rewrite_length);
470 ip1 = vlib_buffer_get_current (b1);
472 hbh1 = (ip6_hop_by_hop_header_t *) (ip1 + 1);
473 /* $$$ tune, rewrite_length is a multiple of 8 */
474 clib_memcpy_fast (hbh1, rewrite, rewrite_length);
476 (ioam_e2e_cache_option_t *) ((u8 *) hbh1 +
477 cm->rewrite_pool_index_offset);
478 e2e->pool_id = (u8) vm->thread_index;
479 e2e->pool_index = pool_index1;
480 ioam_e2e_id_rewrite_handler ((ioam_e2e_id_option_t *)
482 sizeof (ioam_e2e_cache_option_t)),
483 &cm->sr_localsid_ts);
484 /* Patch the protocol chain, insert the h-b-h (type 0) header */
485 hbh1->protocol = ip1->protocol;
488 clib_net_to_host_u16 (ip1->payload_length) + rewrite_length;
489 ip1->payload_length = clib_host_to_net_u16 (new_l1);
494 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
496 if (b0->flags & VLIB_BUFFER_IS_TRACED)
498 ip6_reset_ts_hbh_trace_t *t =
499 vlib_add_trace (vm, node, b0, sizeof (*t));
500 t->next_index = next0;
502 if (b1->flags & VLIB_BUFFER_IS_TRACED)
504 ip6_reset_ts_hbh_trace_t *t =
505 vlib_add_trace (vm, node, b1, sizeof (*t));
506 t->next_index = next1;
511 /* verify speculative enqueue, maybe switch current next frame */
512 vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
513 to_next, n_left_to_next,
514 bi0, bi1, next0, next1);
516 while (n_left_from > 0 && n_left_to_next > 0)
524 ip6_hop_by_hop_header_t *hbh0;
525 u64 *copy_src0, *copy_dst0;
529 next0 = IP6_IOAM_CACHE_TS_INPUT_NEXT_IP6_LOOKUP;
530 /* speculatively enqueue b0 to the current next frame */
538 b0 = vlib_get_buffer (vm, bi0);
540 ip0 = vlib_buffer_get_current (b0);
541 if (IP_PROTOCOL_TCP !=
542 ip6_locate_header (b0, ip0, IP_PROTOCOL_TCP, &tcp_offset0))
546 tcp0 = (tcp_header_t *) ((u8 *) ip0 + tcp_offset0);
547 if ((tcp0->flags & TCP_FLAG_SYN) == TCP_FLAG_SYN &&
548 (tcp0->flags & TCP_FLAG_ACK) == 0)
550 if (no_of_responses > 0)
552 /* Create TS select entry */
553 if (0 == ioam_cache_ts_add (ip0,
559 (tcp0->seq_number) + 1,
560 no_of_responses, now,
561 vm->thread_index, &pool_index0))
566 copy_dst0 = (u64 *) (((u8 *) ip0) - rewrite_length);
567 copy_src0 = (u64 *) ip0;
569 copy_dst0[0] = copy_src0[0];
570 copy_dst0[1] = copy_src0[1];
571 copy_dst0[2] = copy_src0[2];
572 copy_dst0[3] = copy_src0[3];
573 copy_dst0[4] = copy_src0[4];
575 vlib_buffer_advance (b0, -(word) rewrite_length);
576 ip0 = vlib_buffer_get_current (b0);
578 hbh0 = (ip6_hop_by_hop_header_t *) (ip0 + 1);
579 /* $$$ tune, rewrite_length is a multiple of 8 */
580 clib_memcpy_fast (hbh0, rewrite, rewrite_length);
582 (ioam_e2e_cache_option_t *) ((u8 *) hbh0 +
583 cm->rewrite_pool_index_offset);
584 e2e->pool_id = (u8) vm->thread_index;
585 e2e->pool_index = pool_index0;
586 ioam_e2e_id_rewrite_handler ((ioam_e2e_id_option_t *)
588 sizeof (ioam_e2e_cache_option_t)),
589 &cm->sr_localsid_ts);
590 /* Patch the protocol chain, insert the h-b-h (type 0) header */
591 hbh0->protocol = ip0->protocol;
594 clib_net_to_host_u16 (ip0->payload_length) + rewrite_length;
595 ip0->payload_length = clib_host_to_net_u16 (new_l0);
599 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
600 && (b0->flags & VLIB_BUFFER_IS_TRACED)))
602 ip6_reset_ts_hbh_trace_t *t =
603 vlib_add_trace (vm, node, b0, sizeof (*t));
604 t->next_index = next0;
607 /* verify speculative enqueue, maybe switch current next frame */
608 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
609 to_next, n_left_to_next,
613 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
616 vlib_node_increment_counter (vm, cm->ip6_reset_ts_hbh_node_index,
617 IP6_RESET_TS_HBH_ERROR_PROCESSED, processed);
618 vlib_node_increment_counter (vm, cm->ip6_reset_ts_hbh_node_index,
619 IP6_RESET_TS_HBH_ERROR_SAVED, cache_ts_added);
621 return frame->n_vectors;
624 VLIB_REGISTER_NODE (ip6_reset_ts_hbh_node) =
626 .name = "ip6-add-syn-hop-by-hop",
627 .vector_size = sizeof (u32),
628 .format_trace = format_ip6_reset_ts_hbh_trace,
629 .type = VLIB_NODE_TYPE_INTERNAL,
630 .n_errors = ARRAY_LEN (ip6_reset_ts_hbh_error_strings),
631 .error_strings = ip6_reset_ts_hbh_error_strings,
632 /* See ip/lookup.h */
633 .n_next_nodes = IP6_IOAM_CACHE_TS_INPUT_N_NEXT,
636 #define _(s,n) [IP6_IOAM_CACHE_TS_INPUT_NEXT_##s] = n,
637 foreach_ip6_ioam_cache_ts_input_next
643 #ifndef CLIB_MARCH_VARIANT
644 vlib_node_registration_t ioam_cache_ts_timer_tick_node;
645 #endif /* CLIB_MARCH_VARIANT */
650 } ioam_cache_ts_timer_tick_trace_t;
652 /* packet trace format function */
654 format_ioam_cache_ts_timer_tick_trace (u8 * s, va_list * args)
656 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
657 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
658 ioam_cache_ts_timer_tick_trace_t *t =
659 va_arg (*args, ioam_cache_ts_timer_tick_trace_t *);
661 s = format (s, "IOAM_CACHE_TS_TIMER_TICK: thread index %d",
666 #define foreach_ioam_cache_ts_timer_tick_error \
667 _(TIMER, "Timer events")
671 #define _(sym,str) IOAM_CACHE_TS_TIMER_TICK_ERROR_##sym,
672 foreach_ioam_cache_ts_timer_tick_error
674 IOAM_CACHE_TS_TIMER_TICK_N_ERROR,
675 } ioam_cache_ts_timer_tick_error_t;
677 static char *ioam_cache_ts_timer_tick_error_strings[] = {
678 #define _(sym,string) string,
679 foreach_ioam_cache_ts_timer_tick_error
683 #ifndef CLIB_MARCH_VARIANT
685 ioam_cache_ts_timer_node_enable (vlib_main_t * vm, u8 enable)
687 vlib_node_set_state (vm, ioam_cache_ts_timer_tick_node.index,
689 0 ? VLIB_NODE_STATE_DISABLED :
690 VLIB_NODE_STATE_POLLING);
694 expired_cache_ts_timer_callback (u32 * expired_timers)
696 ioam_cache_main_t *cm = &ioam_cache_main;
699 u32 thread_index = vlib_get_thread_index ();
702 for (i = 0; i < vec_len (expired_timers); i++)
704 /* Get pool index and pool id */
705 pool_index = expired_timers[i] & 0x0FFFFFFF;
707 /* Handle expiration */
708 ioam_cache_ts_send (thread_index, pool_index);
711 vlib_node_increment_counter (cm->vlib_main,
712 ioam_cache_ts_timer_tick_node.index,
713 IOAM_CACHE_TS_TIMER_TICK_ERROR_TIMER, count);
715 #endif /* CLIB_MARCH_VARIANT */
718 ioam_cache_ts_timer_tick_node_fn (vlib_main_t * vm,
719 vlib_node_runtime_t * node,
722 ioam_cache_main_t *cm = &ioam_cache_main;
723 u32 my_thread_index = vlib_get_thread_index ();
724 struct timespec ts, tsrem;
726 tw_timer_expire_timers_16t_2w_512sl (&cm->timer_wheels[my_thread_index],
729 ts.tv_nsec = 1000 * 1000 * IOAM_CACHE_TS_TICK;
730 while (nanosleep (&ts, &tsrem) < 0)
737 VLIB_REGISTER_NODE (ioam_cache_ts_timer_tick_node) = {
738 .function = ioam_cache_ts_timer_tick_node_fn,
739 .name = "ioam-cache-ts-timer-tick",
740 .format_trace = format_ioam_cache_ts_timer_tick_trace,
741 .type = VLIB_NODE_TYPE_INPUT,
743 .n_errors = ARRAY_LEN(ioam_cache_ts_timer_tick_error_strings),
744 .error_strings = ioam_cache_ts_timer_tick_error_strings,
748 .state = VLIB_NODE_STATE_DISABLED,
750 /* edit / add dispositions here */
757 * fd.io coding-style-patch-verification: ON
760 * eval: (c-set-style "gnu")