2 * Copyright (C) 2013 Andre Noll <maan@tuebingen.mpg.de>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file sync_filter.c Playback synchronization filter. */
9 #include <netinet/in.h>
10 #include <sys/socket.h>
12 #include <sys/types.h>
13 #include <arpa/inet.h>
18 #include "sync_filter.cmdline.h"
23 #include "buffer_tree.h"
29 struct sync_buddy_info {
37 /* One active buddy */
40 struct sync_buddy_info *sbi;
42 struct list_head node;
45 /* Allocated in ->open() */
46 struct sync_filter_context {
48 struct list_head buddies;
49 struct timeval timeout;
53 /* Allocated and freed in ->parse_config() and ->free_config(). */
54 struct sync_filter_config {
55 struct sync_filter_args_info *conf;
56 struct sync_buddy_info *buddy_info;
59 #define FOR_EACH_BUDDY(_buddy, _list) \
60 list_for_each_entry(_buddy, _list, node)
61 #define FOR_EACH_BUDDY_SAFE(_buddy, _tmp_buddy, _list) \
62 list_for_each_entry_safe(_buddy, _tmp_buddy, _list, node)
64 static void sync_close_buddy(struct sync_buddy *buddy)
66 PARA_DEBUG_LOG("closing %s, fd %d\n", buddy->sbi->url, buddy->fd);
68 list_del(&buddy->node);
72 static void sync_close_buddies(struct sync_filter_context *ctx)
74 struct sync_buddy *buddy, *tmp;
76 FOR_EACH_BUDDY_SAFE(buddy, tmp, &ctx->buddies)
77 sync_close_buddy(buddy);
80 static void sync_close(struct filter_node *fn)
82 struct sync_filter_context *ctx = fn->private_data;
84 sync_close_buddies(ctx);
85 if (ctx->listen_fd >= 0) {
86 close(ctx->listen_fd);
90 fn->private_data = NULL;
93 static void sync_free_config(void *conf)
95 struct sync_filter_config *sfc = conf;
98 for (i = 0; i < sfc->conf->buddy_given; i++) {
99 free(sfc->buddy_info[i].host);
100 freeaddrinfo(sfc->buddy_info[i].ai);
102 sync_filter_cmdline_parser_free(sfc->conf);
106 static void sync_open(struct filter_node *fn)
109 struct sync_filter_config *sfc = fn->conf;
110 struct sync_buddy *buddy;
111 struct sync_filter_context *ctx;
115 ctx = fn->private_data = para_calloc(sizeof(*ctx));
116 INIT_LIST_HEAD(&ctx->buddies);
119 /* create socket to listen for incoming packets */
123 NULL /* no host required */,
125 NULL /* no flowopts */
128 PARA_ERROR_LOG("could not create UDP listening socket %d\n",
129 sfc->conf->port_arg);
132 ctx->listen_fd = ret;
133 PARA_INFO_LOG("listening on fd %d\n", ctx->listen_fd);
135 for (i = 0; i < sfc->conf->buddy_given; i++) {
136 struct sync_buddy_info *sbi = sfc->buddy_info + i;
137 const char *url = sfc->conf->buddy_arg[i];
140 /* make buddy udp socket from address info */
142 ret = makesock_addrinfo(
144 false /* not passive */,
146 NULL /* no flowopts */
149 PARA_WARNING_LOG("could not make socket for %s\n",
154 ret = mark_fd_nonblocking(fd);
156 PARA_ERROR_LOG("unable to set nonblock mode for %s\n",
161 buddy = para_malloc(sizeof(*buddy));
164 buddy->ping_received = false;
165 para_list_add(&buddy->node, &ctx->buddies);
167 PARA_INFO_LOG("opened buddy %s on fd %d\n", url, fd);
170 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
175 * At parse config time, we build an array of struct sync_buddy_info with one
176 * entry for each buddy given in the arguments. This array is not affected by
177 * sync_close(), so information stored there can be used for multiple instances
178 * (para_audiod). We store the resolved url and the ->disabled bit in this
181 static int sync_parse_config(int argc, char **argv, void **result)
184 struct sync_filter_config *sfc;
185 struct sync_filter_args_info *conf = para_malloc(sizeof(*conf));
187 sync_filter_cmdline_parser(argc, argv, conf); /* exits on error */
188 sfc = para_calloc(sizeof(*sfc));
190 n = conf->buddy_given;
191 sfc->buddy_info = para_malloc((n + 1) * sizeof(*sfc->buddy_info));
192 PARA_INFO_LOG("initializing buddy info array of length %d\n", n);
193 for (i = 0; i < n; i++) {
194 const char *url = conf->buddy_arg[i];
195 size_t len = strlen(url);
196 char *host = para_malloc(len + 1);
199 struct sync_buddy_info *sbi = sfc->buddy_info + i;
201 if (!parse_url(url, host, len, &port)) {
203 PARA_ERROR_LOG("could not parse url %s\n", url);
204 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
208 port = conf->port_arg;
209 ret = lookup_address(IPPROTO_UDP, false /* not passive */,
212 PARA_ERROR_LOG("host lookup failure for %s\n", url);
220 sbi->disabled = false;
221 PARA_DEBUG_LOG("buddy #%d: %s\n", i, url);
227 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
228 sync_free_config(sfc);
233 * True if we sent a packet to all buddies and received a packet from each
236 static bool sync_complete(struct sync_filter_context *ctx)
238 struct sync_buddy *buddy;
242 FOR_EACH_BUDDY(buddy, &ctx->buddies)
243 if (!buddy->sbi->disabled && !buddy->ping_received)
248 static void sync_disable_active_buddies(struct sync_filter_context *ctx)
250 struct sync_buddy *buddy;
252 FOR_EACH_BUDDY(buddy, &ctx->buddies) {
253 if (buddy->sbi->disabled)
255 if (buddy->ping_received == true)
257 PARA_NOTICE_LOG("disabling %s\n", buddy->sbi->url);
258 buddy->sbi->disabled = true;
262 static void sync_set_timeout(struct sync_filter_context *ctx,
263 struct sync_filter_config *sfc)
267 ms2tv(sfc->conf->timeout_arg, &to);
268 tv_add(now, &to, &ctx->timeout);
271 static void sync_pre_select(struct sched *s, void *context)
274 struct filter_node *fn = context;
275 struct sync_filter_context *ctx = fn->private_data;
276 struct sync_filter_config *sfc = fn->conf;
278 if (list_empty(&ctx->buddies))
279 return sched_min_delay(s);
280 if (ctx->listen_fd < 0)
281 return sched_min_delay(s);
282 ret = btr_node_status(fn->btrn, 0, BTR_NT_INTERNAL);
284 return sched_min_delay(s);
285 para_fd_set(ctx->listen_fd, &s->rfds, &s->max_fileno);
288 if (ctx->timeout.tv_sec == 0) { /* must ping buddies */
289 sync_set_timeout(ctx, sfc);
290 return sched_min_delay(s);
292 if (sync_complete(ctx)) /* push down what we have */
293 return sched_min_delay(s);
294 sched_request_barrier_or_min_delay(&ctx->timeout, s);
297 static struct sync_buddy *sync_find_buddy(struct sockaddr *addr,
298 struct list_head *list)
300 struct sync_buddy *buddy;
302 FOR_EACH_BUDDY(buddy, list)
303 if (sockaddr_equal(buddy->sbi->ai->ai_addr, addr))
308 static int sync_post_select(__a_unused struct sched *s, void *context)
311 struct filter_node *fn = context;
312 struct sync_filter_context *ctx = fn->private_data;
313 struct sync_filter_config *sfc = fn->conf;
314 struct sync_buddy *buddy, *tmp;
316 if (list_empty(&ctx->buddies))
318 ret = -E_SYNC_LISTEN_FD;
319 if (ctx->listen_fd < 0)
321 ret = btr_node_status(fn->btrn, 0, BTR_NT_INTERNAL);
326 if (ctx->timeout.tv_sec == 0)
327 sync_set_timeout(ctx, sfc);
329 if (tv_diff(&ctx->timeout, now, NULL) < 0) {
330 sync_disable_active_buddies(ctx);
334 if (!ctx->ping_sent) {
335 FOR_EACH_BUDDY_SAFE(buddy, tmp, &ctx->buddies) {
337 PARA_INFO_LOG("pinging %s (%s)\n",
338 buddy->sbi->url, buddy->sbi->disabled?
339 "disabled" : "enabled");
340 ret = xwrite(buddy->fd, &c, 1);
342 PARA_WARNING_LOG("failed to write to %s: %s\n",
343 buddy->sbi->url, para_strerror(-ret));
344 sync_close_buddy(buddy);
347 ctx->ping_sent = true;
349 if (FD_ISSET(ctx->listen_fd, &s->rfds)) {
352 struct sockaddr src_addr;
353 socklen_t len = sizeof(src_addr);
354 ret = recvfrom(ctx->listen_fd, &c, 1, MSG_DONTWAIT,
357 if (errno == EAGAIN || errno == EWOULDBLOCK)
359 ret = -ERRNO_TO_PARA_ERROR(errno);
362 buddy = sync_find_buddy(&src_addr, &ctx->buddies);
364 PARA_NOTICE_LOG("pinged by unknown\n");
367 PARA_DEBUG_LOG("pinged by %s\n", buddy->sbi->url);
368 if (buddy->sbi->disabled) {
369 PARA_NOTICE_LOG("enabling %s\n",
371 buddy->sbi->disabled = false;
373 buddy->ping_received = true;
376 if (!sync_complete(ctx))
379 * Although all enabled buddies are in sync we do not splice out
380 * ourselves immediately. We rather wait until the timeout expires,
381 * or the buddy list has become empty. This opens a time window
382 * for disabled buddies to become enabled by sending us a packet.
384 btr_pushdown(fn->btrn);
387 ret = -E_SYNC_COMPLETE; /* success */
390 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
392 sync_close_buddies(ctx);
393 btr_splice_out_node(&fn->btrn);
399 * The synchronization filter.
401 * \param f Pointer to the struct to initialize.
403 void sync_filter_init(struct filter *f)
405 struct sync_filter_args_info dummy;
407 sync_filter_cmdline_parser_init(&dummy);
409 f->close = sync_close;
410 f->pre_select = sync_pre_select;
411 f->post_select = sync_post_select;
412 f->parse_config = sync_parse_config;
413 f->free_config = sync_free_config;
414 f->help = (struct ggo_help)DEFINE_GGO_HELP(sync_filter);