/*** This file is part of PulseAudio. Copyright 2006 Lennart Poettering PulseAudio is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. PulseAudio is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with PulseAudio; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. ***/ #ifdef HAVE_CONFIG_H #include #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "module-rtp-recv-symdef.h" #include "rtp.h" #include "sdp.h" #include "sap.h" PA_MODULE_AUTHOR("Lennart Poettering"); PA_MODULE_DESCRIPTION("Receive data from a network via RTP/SAP/SDP"); PA_MODULE_VERSION(PACKAGE_VERSION); PA_MODULE_LOAD_ONCE(FALSE); PA_MODULE_USAGE( "sink= " "sap_address= " ); #define SAP_PORT 9875 #define DEFAULT_SAP_ADDRESS "224.0.0.56" #define MEMBLOCKQ_MAXLENGTH (1024*1024*40) #define MAX_SESSIONS 16 #define DEATH_TIMEOUT 20 #define RATE_UPDATE_INTERVAL (5*PA_USEC_PER_SEC) #define LATENCY_USEC (500*PA_USEC_PER_MSEC) static const char* const valid_modargs[] = { "sink", "sap_address", NULL }; struct session { struct userdata *userdata; PA_LLIST_FIELDS(struct session); pa_sink_input *sink_input; pa_memblockq *memblockq; pa_bool_t first_packet; uint32_t ssrc; uint32_t offset; struct pa_sdp_info sdp_info; pa_rtp_context rtp_context; pa_rtpoll_item *rtpoll_item; pa_atomic_t timestamp; pa_usec_t intended_latency; pa_usec_t sink_latency; pa_usec_t last_rate_update; pa_usec_t last_latency; double estimated_rate; double avg_estimated_rate; }; struct userdata { pa_module *module; pa_core *core; pa_sap_context sap_context; pa_io_event* sap_event; pa_time_event *check_death_event; char *sink_name; PA_LLIST_HEAD(struct session, sessions); pa_hashmap *by_origin; int n_sessions; }; static void session_free(struct session *s); /* Called from I/O thread context */ static int sink_input_process_msg(pa_msgobject *o, int code, void *data, int64_t offset, pa_memchunk *chunk) { struct session *s = PA_SINK_INPUT(o)->userdata; switch (code) { case PA_SINK_INPUT_MESSAGE_GET_LATENCY: *((pa_usec_t*) data) = pa_bytes_to_usec(pa_memblockq_get_length(s->memblockq), &s->sink_input->sample_spec); /* Fall through, the default handler will add in the extra * latency added by the resampler */ break; } return pa_sink_input_process_msg(o, code, data, offset, chunk); } /* Called from I/O thread context */ static int sink_input_pop_cb(pa_sink_input *i, size_t length, pa_memchunk *chunk) { struct session *s; pa_sink_input_assert_ref(i); pa_assert_se(s = i->userdata); if (pa_memblockq_peek(s->memblockq, chunk) < 0) return -1; pa_memblockq_drop(s->memblockq, chunk->length); return 0; } /* Called from I/O thread context */ static void sink_input_process_rewind_cb(pa_sink_input *i, size_t nbytes) { struct session *s; pa_sink_input_assert_ref(i); pa_assert_se(s = i->userdata); pa_memblockq_rewind(s->memblockq, nbytes); } /* Called from I/O thread context */ static void sink_input_update_max_rewind_cb(pa_sink_input *i, size_t nbytes) { struct session *s; pa_sink_input_assert_ref(i); pa_assert_se(s = i->userdata); pa_memblockq_set_maxrewind(s->memblockq, nbytes); } /* Called from main context */ static void sink_input_kill(pa_sink_input* i) { struct session *s; pa_sink_input_assert_ref(i); pa_assert_se(s = i->userdata); session_free(s); } /* Called from IO context */ static void sink_input_suspend_within_thread(pa_sink_input* i, pa_bool_t b) { struct session *s; pa_sink_input_assert_ref(i); pa_assert_se(s = i->userdata); if (b) pa_memblockq_flush_read(s->memblockq); else s->first_packet = FALSE; } /* Called from I/O thread context */ static int rtpoll_work_cb(pa_rtpoll_item *i) { pa_memchunk chunk; int64_t k, j, delta; struct timeval now = { 0, 0 }; struct session *s; struct pollfd *p; pa_assert_se(s = pa_rtpoll_item_get_userdata(i)); p = pa_rtpoll_item_get_pollfd(i, NULL); if (p->revents & (POLLERR|POLLNVAL|POLLHUP|POLLOUT)) { pa_log("poll() signalled bad revents."); return -1; } if ((p->revents & POLLIN) == 0) return 0; p->revents = 0; if (pa_rtp_recv(&s->rtp_context, &chunk, s->userdata->module->core->mempool, &now) < 0) return 0; if (s->sdp_info.payload != s->rtp_context.payload || !PA_SINK_IS_OPENED(s->sink_input->sink->thread_info.state)) { pa_memblock_unref(chunk.memblock); return 0; } if (!s->first_packet) { s->first_packet = TRUE; s->ssrc = s->rtp_context.ssrc; s->offset = s->rtp_context.timestamp; if (s->ssrc == s->userdata->module->core->cookie) pa_log_warn("Detected RTP packet loop!"); } else { if (s->ssrc != s->rtp_context.ssrc) { pa_memblock_unref(chunk.memblock); return 0; } } /* Check whether there was a timestamp overflow */ k = (int64_t) s->rtp_context.timestamp - (int64_t) s->offset; j = (int64_t) 0x100000000LL - (int64_t) s->offset + (int64_t) s->rtp_context.timestamp; if ((k < 0 ? -k : k) < (j < 0 ? -j : j)) delta = k; else delta = j; pa_memblockq_seek(s->memblockq, delta * (int64_t) s->rtp_context.frame_size, PA_SEEK_RELATIVE, TRUE); if (now.tv_sec == 0) { PA_ONCE_BEGIN { pa_log_warn("Using artificial time instead of timestamp"); } PA_ONCE_END; pa_rtclock_get(&now); } else pa_rtclock_from_wallclock(&now); if (pa_memblockq_push(s->memblockq, &chunk) < 0) { pa_log_warn("Queue overrun"); pa_memblockq_seek(s->memblockq, (int64_t) chunk.length, PA_SEEK_RELATIVE, TRUE); } /* pa_log("blocks in q: %u", pa_memblockq_get_nblocks(s->memblockq)); */ pa_memblock_unref(chunk.memblock); /* The next timestamp we expect */ s->offset = s->rtp_context.timestamp + (uint32_t) (chunk.length / s->rtp_context.frame_size); pa_atomic_store(&s->timestamp, (int) now.tv_sec); if (s->last_rate_update + RATE_UPDATE_INTERVAL < pa_timeval_load(&now)) { pa_usec_t wi, ri, render_delay, sink_delay = 0, latency; uint32_t base_rate = s->sink_input->sink->sample_spec.rate; uint32_t current_rate = s->sink_input->sample_spec.rate; uint32_t new_rate; double estimated_rate, alpha = 0.02; pa_log_debug("Updating sample rate"); wi = pa_bytes_to_usec((uint64_t) pa_memblockq_get_write_index(s->memblockq), &s->sink_input->sample_spec); ri = pa_bytes_to_usec((uint64_t) pa_memblockq_get_read_index(s->memblockq), &s->sink_input->sample_spec); pa_log_debug("wi=%lu ri=%lu", (unsigned long) wi, (unsigned long) ri); sink_delay = pa_sink_get_latency_within_thread(s->sink_input->sink); render_delay = pa_bytes_to_usec(pa_memblockq_get_length(s->sink_input->thread_info.render_memblockq), &s->sink_input->sink->sample_spec); if (ri > render_delay+sink_delay) ri -= render_delay+sink_delay; else ri = 0; if (wi < ri) latency = 0; else latency = wi - ri; pa_log_debug("Write index deviates by %0.2f ms, expected %0.2f ms", (double) latency/PA_USEC_PER_MSEC, (double) s->intended_latency/PA_USEC_PER_MSEC); /* The buffer is filling with some unknown rate R̂ samples/second. If the rate of reading in * the last T seconds was Rⁿ, then the increase in buffer latency ΔLⁿ = Lⁿ - Lⁿ⁻ⁱ in that * same period is ΔLⁿ = (TR̂ - TRⁿ) / R̂, giving the estimated target rate * T * R̂ = ─────────────── Rⁿ . (1) * T - (Lⁿ - Lⁿ⁻ⁱ) * * Setting the sample rate to R̂ results in the latency being constant (if the estimate of R̂ * is correct). But there is also the requirement to keep the buffer at a predefined target * latency L̂. So instead of setting Rⁿ⁺ⁱ to R̂ immediately, the strategy will be to reduce R * from Rⁿ⁺ⁱ to R̂ in a steps of T seconds, where Rⁿ⁺ⁱ is chosen such that in the total time * aT the latency is reduced from Lⁿ to L̂. This strategy translates to the requirements * ₐ R̂ - Rⁿ⁺ʲ a-j+1 j-1 * Σ T ────────── = L̂ - Lⁿ with Rⁿ⁺ʲ = ───── Rⁿ⁺ⁱ + ───── R̂ . * ʲ⁼ⁱ R̂ a a * Solving for Rⁿ⁺ⁱ gives * T - ²∕ₐ₊₁(L̂ - Lⁿ) * Rⁿ⁺ⁱ = ───────────────── R̂ . (2) * T * In the code below a = 7 is used. * * Equation (1) is not directly used in (2), but instead an exponentially weighted average * of the estimated rate R̂ is used. This average R̅ is defined as * R̅ⁿ = α R̂ⁿ + (1-α) R̅ⁿ⁻ⁱ . * Because it is difficult to find a fixed value for the coefficient α such that the * averaging is without significant lag but oscillations are filtered out, a heuristic is * used. When the successive estimates R̂ⁿ do not change much then α→1, but when there is a * sudden spike in the estimated rate α→0, such that the deviation is given little weight. */ estimated_rate = (double) current_rate * (double) RATE_UPDATE_INTERVAL / (double) (RATE_UPDATE_INTERVAL + s->last_latency - latency); if (fabs(s->estimated_rate - s->avg_estimated_rate) > 1) { double ratio = (estimated_rate + s->estimated_rate - 2*s->avg_estimated_rate) / (s->estimated_rate - s->avg_estimated_rate); alpha = PA_CLAMP(2 * (ratio + fabs(ratio)) / (4 + ratio*ratio), 0.02, 0.8); } s->avg_estimated_rate = alpha * estimated_rate + (1-alpha) * s->avg_estimated_rate; s->estimated_rate = estimated_rate; pa_log_debug("Estimated target rate: %.0f Hz, using average of %.0f Hz (α=%.3f)", estimated_rate, s->avg_estimated_rate, alpha); new_rate = (uint32_t) ((double) (RATE_UPDATE_INTERVAL + latency/4 - s->intended_latency/4) / (double) RATE_UPDATE_INTERVAL * s->avg_estimated_rate); s->last_latency = latency; if (new_rate < (uint32_t) (base_rate*0.8) || new_rate > (uint32_t) (base_rate*1.25)) { pa_log_warn("Sample rates too different, not adjusting (%u vs. %u).", base_rate, new_rate); new_rate = base_rate; } else { if (base_rate < new_rate + 20 && new_rate < base_rate + 20) new_rate = base_rate; /* Do the adjustment in small steps; 2‰ can be considered inaudible */ if (new_rate < (uint32_t) (current_rate*0.998) || new_rate > (uint32_t) (current_rate*1.002)) { pa_log_info("New rate of %u Hz not within 2‰ of %u Hz, forcing smaller adjustment", new_rate, current_rate); new_rate = PA_CLAMP(new_rate, (uint32_t) (current_rate*0.998), (uint32_t) (current_rate*1.002)); } } s->sink_input->sample_spec.rate = new_rate; pa_assert(pa_sample_spec_valid(&s->sink_input->sample_spec)); pa_resampler_set_input_rate(s->sink_input->thread_info.resampler, s->sink_input->sample_spec.rate); pa_log_debug("Updated sampling rate to %lu Hz.", (unsigned long) s->sink_input->sample_spec.rate); s->last_rate_update = pa_timeval_load(&now); } if (pa_memblockq_is_readable(s->memblockq) && s->sink_input->thread_info.underrun_for > 0) { pa_log_debug("Requesting rewind due to end of underrun"); pa_sink_input_request_rewind(s->sink_input, (size_t) (s->sink_input->thread_info.underrun_for == (uint64_t) -1 ? 0 : s->sink_input->thread_info.underrun_for), FALSE, TRUE, FALSE); } return 1; } /* Called from I/O thread context */ static void sink_input_attach(pa_sink_input *i) { struct session *s; struct pollfd *p; pa_sink_input_assert_ref(i); pa_assert_se(s = i->userdata); pa_assert(!s->rtpoll_item); s->rtpoll_item = pa_rtpoll_item_new(i->sink->thread_info.rtpoll, PA_RTPOLL_LATE, 1); p = pa_rtpoll_item_get_pollfd(s->rtpoll_item, NULL); p->fd = s->rtp_context.fd; p->events = POLLIN; p->revents = 0; pa_rtpoll_item_set_work_callback(s->rtpoll_item, rtpoll_work_cb); pa_rtpoll_item_set_userdata(s->rtpoll_item, s); } /* Called from I/O thread context */ static void sink_input_detach(pa_sink_input *i) { struct session *s; pa_sink_input_assert_ref(i); pa_assert_se(s = i->userdata); pa_assert(s->rtpoll_item); pa_rtpoll_item_free(s->rtpoll_item); s->rtpoll_item = NULL; } static int mcast_socket(const struct sockaddr* sa, socklen_t salen) { int af, fd = -1, r, one; pa_assert(sa); pa_assert(salen > 0); af = sa->sa_family; if ((fd = pa_socket_cloexec(af, SOCK_DGRAM, 0)) < 0) { pa_log("Failed to create socket: %s", pa_cstrerror(errno)); goto fail; } pa_make_udp_socket_low_delay(fd); one = 1; if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMP, &one, sizeof(one)) < 0) { pa_log("SO_TIMESTAMP failed: %s", pa_cstrerror(errno)); goto fail; } one = 1; if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) < 0) { pa_log("SO_REUSEADDR failed: %s", pa_cstrerror(errno)); goto fail; } if (af == AF_INET) { struct ip_mreq mr4; memset(&mr4, 0, sizeof(mr4)); mr4.imr_multiaddr = ((const struct sockaddr_in*) sa)->sin_addr; r = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mr4, sizeof(mr4)); #ifdef HAVE_IPV6 } else { struct ipv6_mreq mr6; memset(&mr6, 0, sizeof(mr6)); mr6.ipv6mr_multiaddr = ((const struct sockaddr_in6*) sa)->sin6_addr; r = setsockopt(fd, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mr6, sizeof(mr6)); #endif } if (r < 0) { pa_log_info("Joining mcast group failed: %s", pa_cstrerror(errno)); goto fail; } if (bind(fd, sa, salen) < 0) { pa_log("bind() failed: %s", pa_cstrerror(errno)); goto fail; } return fd; fail: if (fd >= 0) close(fd); return -1; } static struct session *session_new(struct userdata *u, const pa_sdp_info *sdp_info) { struct session *s = NULL; pa_sink *sink; int fd = -1; pa_memchunk silence; pa_sink_input_new_data data; struct timeval now; pa_assert(u); pa_assert(sdp_info); if (u->n_sessions >= MAX_SESSIONS) { pa_log("Session limit reached."); goto fail; } if (!(sink = pa_namereg_get(u->module->core, u->sink_name, PA_NAMEREG_SINK))) { pa_log("Sink does not exist."); goto fail; } pa_rtclock_get(&now); s = pa_xnew0(struct session, 1); s->userdata = u; s->first_packet = FALSE; s->sdp_info = *sdp_info; s->rtpoll_item = NULL; s->intended_latency = LATENCY_USEC; s->last_rate_update = pa_timeval_load(&now); s->last_latency = LATENCY_USEC; s->estimated_rate = (double) sink->sample_spec.rate; s->avg_estimated_rate = (double) sink->sample_spec.rate; pa_atomic_store(&s->timestamp, (int) now.tv_sec); if ((fd = mcast_socket((const struct sockaddr*) &sdp_info->sa, sdp_info->salen)) < 0) goto fail; pa_sink_input_new_data_init(&data); data.sink = sink; data.driver = __FILE__; pa_proplist_sets(data.proplist, PA_PROP_MEDIA_ROLE, "stream"); pa_proplist_setf(data.proplist, PA_PROP_MEDIA_NAME, "RTP Stream%s%s%s", sdp_info->session_name ? " (" : "", sdp_info->session_name ? sdp_info->session_name : "", sdp_info->session_name ? ")" : ""); if (sdp_info->session_name) pa_proplist_sets(data.proplist, "rtp.session", sdp_info->session_name); pa_proplist_sets(data.proplist, "rtp.origin", sdp_info->origin); pa_proplist_setf(data.proplist, "rtp.payload", "%u", (unsigned) sdp_info->payload); data.module = u->module; pa_sink_input_new_data_set_sample_spec(&data, &sdp_info->sample_spec); data.flags = PA_SINK_INPUT_VARIABLE_RATE; pa_sink_input_new(&s->sink_input, u->module->core, &data); pa_sink_input_new_data_done(&data); if (!s->sink_input) { pa_log("Failed to create sink input."); goto fail; } s->sink_input->userdata = s; s->sink_input->parent.process_msg = sink_input_process_msg; s->sink_input->pop = sink_input_pop_cb; s->sink_input->process_rewind = sink_input_process_rewind_cb; s->sink_input->update_max_rewind = sink_input_update_max_rewind_cb; s->sink_input->kill = sink_input_kill; s->sink_input->attach = sink_input_attach; s->sink_input->detach = sink_input_detach; s->sink_input->suspend_within_thread = sink_input_suspend_within_thread; pa_sink_input_get_silence(s->sink_input, &silence); s->sink_latency = pa_sink_input_set_requested_latency(s->sink_input, s->intended_latency/2); if (s->intended_latency < s->sink_latency*2) s->intended_latency = s->sink_latency*2; s->memblockq = pa_memblockq_new( 0, MEMBLOCKQ_MAXLENGTH, MEMBLOCKQ_MAXLENGTH, pa_frame_size(&s->sink_input->sample_spec), pa_usec_to_bytes(s->intended_latency - s->sink_latency, &s->sink_input->sample_spec), 0, 0, &silence); pa_memblock_unref(silence.memblock); pa_rtp_context_init_recv(&s->rtp_context, fd, pa_frame_size(&s->sdp_info.sample_spec)); pa_hashmap_put(s->userdata->by_origin, s->sdp_info.origin, s); u->n_sessions++; PA_LLIST_PREPEND(struct session, s->userdata->sessions, s); pa_sink_input_put(s->sink_input); pa_log_info("New session '%s'", s->sdp_info.session_name); return s; fail: pa_xfree(s); if (fd >= 0) pa_close(fd); return NULL; } static void session_free(struct session *s) { pa_assert(s); pa_log_info("Freeing session '%s'", s->sdp_info.session_name); pa_sink_input_unlink(s->sink_input); pa_sink_input_unref(s->sink_input); PA_LLIST_REMOVE(struct session, s->userdata->sessions, s); pa_assert(s->userdata->n_sessions >= 1); s->userdata->n_sessions--; pa_hashmap_remove(s->userdata->by_origin, s->sdp_info.origin); pa_memblockq_free(s->memblockq); pa_sdp_info_destroy(&s->sdp_info); pa_rtp_context_destroy(&s->rtp_context); pa_xfree(s); } static void sap_event_cb(pa_mainloop_api *m, pa_io_event *e, int fd, pa_io_event_flags_t flags, void *userdata) { struct userdata *u = userdata; pa_bool_t goodbye = FALSE; pa_sdp_info info; struct session *s; pa_assert(m); pa_assert(e); pa_assert(u); pa_assert(fd == u->sap_context.fd); pa_assert(flags == PA_IO_EVENT_INPUT); if (pa_sap_recv(&u->sap_context, &goodbye) < 0) return; if (!pa_sdp_parse(u->sap_context.sdp_data, &info, goodbye)) return; if (goodbye) { if ((s = pa_hashmap_get(u->by_origin, info.origin))) session_free(s); pa_sdp_info_destroy(&info); } else { if (!(s = pa_hashmap_get(u->by_origin, info.origin))) { if (!session_new(u, &info)) pa_sdp_info_destroy(&info); } else { struct timeval now; pa_rtclock_get(&now); pa_atomic_store(&s->timestamp, (int) now.tv_sec); pa_sdp_info_destroy(&info); } } } static void check_death_event_cb(pa_mainloop_api *m, pa_time_event *t, const struct timeval *tv, void *userdata) { struct session *s, *n; struct userdata *u = userdata; struct timeval now; pa_assert(m); pa_assert(t); pa_assert(u); pa_rtclock_get(&now); pa_log_debug("Checking for dead streams ..."); for (s = u->sessions; s; s = n) { int k; n = s->next; k = pa_atomic_load(&s->timestamp); if (k + DEATH_TIMEOUT < now.tv_sec) session_free(s); } /* Restart timer */ pa_core_rttime_restart(u->module->core, t, pa_rtclock_now() + DEATH_TIMEOUT * PA_USEC_PER_SEC); } int pa__init(pa_module*m) { struct userdata *u; pa_modargs *ma = NULL; struct sockaddr_in sa4; #ifdef HAVE_IPV6 struct sockaddr_in6 sa6; #endif struct sockaddr *sa; socklen_t salen; const char *sap_address; int fd = -1; pa_assert(m); if (!(ma = pa_modargs_new(m->argument, valid_modargs))) { pa_log("failed to parse module arguments"); goto fail; } sap_address = pa_modargs_get_value(ma, "sap_address", DEFAULT_SAP_ADDRESS); if (inet_pton(AF_INET, sap_address, &sa4.sin_addr) > 0) { sa4.sin_family = AF_INET; sa4.sin_port = htons(SAP_PORT); sa = (struct sockaddr*) &sa4; salen = sizeof(sa4); #ifdef HAVE_IPV6 } else if (inet_pton(AF_INET6, sap_address, &sa6.sin6_addr) > 0) { sa6.sin6_family = AF_INET6; sa6.sin6_port = htons(SAP_PORT); sa = (struct sockaddr*) &sa6; salen = sizeof(sa6); #endif } else { pa_log("Invalid SAP address '%s'", sap_address); goto fail; } if ((fd = mcast_socket(sa, salen)) < 0) goto fail; m->userdata = u = pa_xnew(struct userdata, 1); u->module = m; u->core = m->core; u->sink_name = pa_xstrdup(pa_modargs_get_value(ma, "sink", NULL)); u->sap_event = m->core->mainloop->io_new(m->core->mainloop, fd, PA_IO_EVENT_INPUT, sap_event_cb, u); pa_sap_context_init_recv(&u->sap_context, fd); PA_LLIST_HEAD_INIT(struct session, u->sessions); u->n_sessions = 0; u->by_origin = pa_hashmap_new(pa_idxset_string_hash_func, pa_idxset_string_compare_func); u->check_death_event = pa_core_rttime_new(m->core, pa_rtclock_now() + DEATH_TIMEOUT * PA_USEC_PER_SEC, check_death_event_cb, u); pa_modargs_free(ma); return 0; fail: if (ma) pa_modargs_free(ma); if (fd >= 0) pa_close(fd); return -1; } void pa__done(pa_module*m) { struct userdata *u; struct session *s; pa_assert(m); if (!(u = m->userdata)) return; if (u->sap_event) m->core->mainloop->io_free(u->sap_event); if (u->check_death_event) m->core->mainloop->time_free(u->check_death_event); pa_sap_context_destroy(&u->sap_context); if (u->by_origin) { while ((s = pa_hashmap_first(u->by_origin))) session_free(s); pa_hashmap_free(u->by_origin, NULL, NULL); } pa_xfree(u->sink_name); pa_xfree(u); }