static void lookup_destroy(AvahiWideAreaLookup *l) { AvahiWideAreaLookup *t; assert(l); lookup_stop(l); t = avahi_hashmap_lookup(l->engine->lookups_by_key, l->key); AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, by_key, t, l); if (t) avahi_hashmap_replace(l->engine->lookups_by_key, avahi_key_ref(l->key), t); else avahi_hashmap_remove(l->engine->lookups_by_key, l->key); AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, lookups, l->engine->lookups, l); avahi_hashmap_remove(l->engine->lookups_by_id, &l->id); avahi_dns_packet_free(l->packet); if (l->key) avahi_key_unref(l->key); if (l->cname_key) avahi_key_unref(l->cname_key); avahi_free(l); }
static void send_response_packet(AvahiResponseScheduler *s, AvahiResponseJob *rj) { AvahiDnsPacket *p; unsigned n; assert(s); assert(rj); if (!(p = avahi_dns_packet_new_response(s->interface->hardware->mtu, 1))) return; /* OOM */ n = 1; /* Put it in the packet. */ if (packet_add_response_job(s, p, rj)) { /* Try to fill up packet with more responses, if available */ while (s->jobs) { if (!packet_add_response_job(s, p, s->jobs)) break; n++; } } else { size_t size; avahi_dns_packet_free(p); /* OK, the packet was too small, so create one that fits */ size = avahi_record_get_estimate_size(rj->record) + AVAHI_DNS_PACKET_HEADER_SIZE; if (!(p = avahi_dns_packet_new_response(size + AVAHI_DNS_PACKET_EXTRA_SIZE, 1))) return; /* OOM */ if (!packet_add_response_job(s, p, rj)) { avahi_dns_packet_free(p); avahi_log_warn("Record too large, cannot send"); job_mark_done(s, rj); return; } } avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n); avahi_interface_send_packet(s->interface, p, AVAHI_MDNS); avahi_dns_packet_free(p); }
static void append_known_answers_and_send(AvahiQueryScheduler *s, AvahiDnsPacket *p) { AvahiKnownAnswer *ka; unsigned n; assert(s); assert(p); n = 0; while ((ka = s->known_answers)) { int too_large = 0; while (!avahi_dns_packet_append_record(p, ka->record, 0, 0)) { if (avahi_dns_packet_is_empty(p)) { /* The record is too large to fit into one packet, so there's no point in sending it. Better is letting the owner of the record send it as a response. This has the advantage of a cache refresh. */ too_large = 1; break; } avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) | AVAHI_DNS_FLAG_TC); avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n); avahi_interface_send_packet(s->interface, p, AVAHI_MDNS); avahi_dns_packet_free(p); p = avahi_dns_packet_new_query(s->interface->hardware->mtu); n = 0; } AVAHI_LLIST_REMOVE(AvahiKnownAnswer, known_answer, s->known_answers, ka); avahi_record_unref(ka->record); avahi_free(ka); if (!too_large) n++; } avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_ANCOUNT, n); avahi_interface_send_packet(s->interface, p, AVAHI_MDNS); avahi_dns_packet_free(p); }
static void socket_event(AVAHI_GCC_UNUSED AvahiWatch *w, int fd, AVAHI_GCC_UNUSED AvahiWatchEvent events, void *userdata) { AvahiWideAreaLookupEngine *e = userdata; AvahiDnsPacket *p = NULL; if (fd == e->fd_ipv4) p = avahi_recv_dns_packet_ipv4(e->fd_ipv4, NULL, NULL, NULL, NULL, NULL); else { assert(fd == e->fd_ipv6); p = avahi_recv_dns_packet_ipv6(e->fd_ipv6, NULL, NULL, NULL, NULL, NULL); } if (p) { handle_packet(e, p); avahi_dns_packet_free(p); } }
void avahi_llmnr_query_job_destroy(AvahiLLMNRQueryScheduler *s, AvahiLLMNRQueryJob *qj) { assert(s); assert(qj); /* Free lq */ avahi_llmnr_query_destroy(qj->lq); /* Free dns packet and time_event */ if (qj->p) avahi_dns_packet_free(qj->p); if(qj->time_event) avahi_time_event_free(qj->time_event); /* Remove from the lists */ AVAHI_LLIST_REMOVE(AvahiLLMNRQueryJob, jobs_by_scheduler, s->jobs, qj); AVAHI_LLIST_REMOVE(AvahiLLMNRQueryJob, jobs_by_interface, s->i->llmnr.queryjobs, qj); avahi_free(qj); }
AvahiWideAreaLookup *avahi_wide_area_lookup_new( AvahiWideAreaLookupEngine *e, AvahiKey *key, AvahiWideAreaLookupCallback callback, void *userdata) { struct timeval tv; AvahiWideAreaLookup *l, *t; uint8_t *p; assert(e); assert(key); assert(callback); assert(userdata); l = avahi_new(AvahiWideAreaLookup, 1); l->engine = e; l->dead = 0; l->key = avahi_key_ref(key); l->cname_key = avahi_key_new_cname(l->key); l->callback = callback; l->userdata = userdata; /* If more than 65K wide area quries are issued simultaneously, * this will break. This should be limited by some higher level */ for (;; e->next_id++) if (!find_lookup(e, e->next_id)) break; /* This ID is not yet used. */ l->id = e->next_id++; /* We keep the packet around in case we need to repeat our query */ l->packet = avahi_dns_packet_new(0); avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_ID, (uint16_t) l->id); avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 1, 0, 0, 0, 0, 0)); p = avahi_dns_packet_append_key(l->packet, key, 0); assert(p); avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_QDCOUNT, 1); if (send_to_dns_server(l, l->packet) < 0) { avahi_log_error(__FILE__": Failed to send packet."); avahi_dns_packet_free(l->packet); avahi_key_unref(l->key); if (l->cname_key) avahi_key_unref(l->cname_key); avahi_free(l); return NULL; } l->n_send = 1; l->time_event = avahi_time_event_new(e->server->time_event_queue, avahi_elapse_time(&tv, 500, 0), sender_timeout_callback, l); avahi_hashmap_insert(e->lookups_by_id, &l->id, l); t = avahi_hashmap_lookup(e->lookups_by_key, l->key); AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, by_key, t, l); avahi_hashmap_replace(e->lookups_by_key, avahi_key_ref(l->key), t); AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, lookups, e->lookups, l); return l; }
static void elapse_callback(AVAHI_GCC_UNUSED AvahiTimeEvent *e, void* data) { AvahiProbeJob *pj = data, *next; AvahiProbeScheduler *s; AvahiDnsPacket *p; unsigned n; assert(pj); s = pj->scheduler; if (pj->done) { /* Lets remove it from the history */ job_free(s, pj); return; } if (!(p = avahi_dns_packet_new_query(s->interface->hardware->mtu))) return; /* OOM */ n = 1; /* Add the import probe */ if (!packet_add_probe_query(s, p, pj)) { size_t size; AvahiKey *k; int b; avahi_dns_packet_free(p); /* The probe didn't fit in the package, so let's allocate a larger one */ size = avahi_key_get_estimate_size(pj->record->key) + avahi_record_get_estimate_size(pj->record) + AVAHI_DNS_PACKET_HEADER_SIZE; if (size > AVAHI_DNS_PACKET_SIZE_MAX) size = AVAHI_DNS_PACKET_SIZE_MAX; if (!(p = avahi_dns_packet_new_query(size))) return; /* OOM */ if (!(k = avahi_key_new(pj->record->key->name, pj->record->key->clazz, AVAHI_DNS_TYPE_ANY))) { avahi_dns_packet_free(p); return; /* OOM */ } b = avahi_dns_packet_append_key(p, k, 0) && avahi_dns_packet_append_record(p, pj->record, 0, 0); avahi_key_unref(k); if (b) { avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_NSCOUNT, 1); avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, 1); avahi_interface_send_packet(s->interface, p); } else avahi_log_warn("Probe record too large, cannot send"); avahi_dns_packet_free(p); job_mark_done(s, pj); return; } /* Try to fill up packet with more probes, if available */ for (pj = s->jobs; pj; pj = pj->jobs_next) { if (pj->chosen) continue; if (!packet_add_probe_query(s, p, pj)) break; n++; } avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, n); n = 0; /* Now add the chosen records to the authorative section */ for (pj = s->jobs; pj; pj = next) { next = pj->jobs_next; if (!pj->chosen) continue; if (!avahi_dns_packet_append_record(p, pj->record, 0, 0)) { /* avahi_log_warn("Bad probe size estimate!"); */ /* Unmark all following jobs */ for (; pj; pj = pj->jobs_next) pj->chosen = 0; break; } job_mark_done(s, pj); n ++; } avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_NSCOUNT, n); /* Send it now */ avahi_interface_send_packet(s->interface, p); avahi_dns_packet_free(p); }
int main(AVAHI_GCC_UNUSED int argc, AVAHI_GCC_UNUSED char *argv[]) { char t[AVAHI_DOMAIN_NAME_MAX], *m; const char *a, *b, *c, *d; AvahiDnsPacket *p; AvahiRecord *r, *r2; uint8_t rdata[AVAHI_DNS_RDATA_MAX]; size_t l; p = avahi_dns_packet_new(0); assert(avahi_dns_packet_append_name(p, a = "Ahello.hello.hello.de.")); assert(avahi_dns_packet_append_name(p, b = "Bthis is a test.hello.de.")); assert(avahi_dns_packet_append_name(p, c = "Cthis\\.is\\.a\\.test\\.with\\.dots.hello.de.")); assert(avahi_dns_packet_append_name(p, d = "Dthis\\\\is another test.hello.de.")); avahi_hexdump(AVAHI_DNS_PACKET_DATA(p), p->size); assert(avahi_dns_packet_consume_name(p, t, sizeof(t)) == 0); avahi_log_debug(">%s<", t); assert(avahi_domain_equal(a, t)); assert(avahi_dns_packet_consume_name(p, t, sizeof(t)) == 0); avahi_log_debug(">%s<", t); assert(avahi_domain_equal(b, t)); assert(avahi_dns_packet_consume_name(p, t, sizeof(t)) == 0); avahi_log_debug(">%s<", t); assert(avahi_domain_equal(c, t)); assert(avahi_dns_packet_consume_name(p, t, sizeof(t)) == 0); avahi_log_debug(">%s<", t); assert(avahi_domain_equal(d, t)); avahi_dns_packet_free(p); /* RDATA PARSING AND SERIALIZATION */ /* Create an AvahiRecord with some usful data */ r = avahi_record_new_full("foobar.local", AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_HINFO, AVAHI_DEFAULT_TTL); assert(r); r->data.hinfo.cpu = avahi_strdup("FOO"); r->data.hinfo.os = avahi_strdup("BAR"); /* Serialize it into a blob */ assert((l = avahi_rdata_serialize(r, rdata, sizeof(rdata))) != (size_t) -1); /* Print it */ avahi_hexdump(rdata, l); /* Create a new record and fill in the data from the blob */ r2 = avahi_record_new(r->key, AVAHI_DEFAULT_TTL); assert(r2); assert(avahi_rdata_parse(r2, rdata, l) >= 0); /* Compare both versions */ assert(avahi_record_equal_no_ttl(r, r2)); /* Free the records */ avahi_record_unref(r); avahi_record_unref(r2); r = avahi_record_new_full("foobar", 77, 77, AVAHI_DEFAULT_TTL); assert(r); assert(r->data.generic.data = avahi_memdup("HALLO", r->data.generic.size = 5)); m = avahi_record_to_string(r); assert(m); avahi_log_debug(">%s<", m); avahi_free(m); avahi_record_unref(r); return 0; }
AvahiDnsPacket *avahi_recv_dns_packet_ipv6( int fd, AvahiIPv6Address *ret_src_address, uint16_t *ret_src_port, AvahiIPv6Address *ret_dst_address, AvahiIfIndex *ret_iface, uint8_t *ret_ttl) { AvahiDnsPacket *p = NULL; struct msghdr msg; struct iovec io; size_t aux[1024 / sizeof(size_t)]; ssize_t l; int ms; struct cmsghdr *cmsg; int found_ttl = 0, found_iface = 0; struct sockaddr_in6 sa; assert(fd >= 0); if (ioctl(fd, FIONREAD, &ms) < 0) { avahi_log_warn("ioctl(): %s", strerror(errno)); goto fail; } if (ms < 0) { avahi_log_warn("FIONREAD returned negative value."); goto fail; } p = avahi_dns_packet_new(ms + AVAHI_DNS_PACKET_EXTRA_SIZE); io.iov_base = AVAHI_DNS_PACKET_DATA(p); io.iov_len = p->max_size; memset(&msg, 0, sizeof(msg)); msg.msg_name = (struct sockaddr*) &sa; msg.msg_namelen = sizeof(sa); msg.msg_iov = &io; msg.msg_iovlen = 1; msg.msg_control = aux; msg.msg_controllen = sizeof(aux); msg.msg_flags = 0; if ((l = recvmsg(fd, &msg, 0)) < 0) { /* Linux returns EAGAIN when an invalid IP packet has been received. We suppress warnings in this case because this might create quite a bit of log traffic on machines with unstable links. (See #60) */ if (errno != EAGAIN) avahi_log_warn("recvmsg(): %s", strerror(errno)); goto fail; } assert(!(msg.msg_flags & MSG_CTRUNC)); assert(!(msg.msg_flags & MSG_TRUNC)); p->size = (size_t) l; if (ret_src_port) *ret_src_port = avahi_port_from_sockaddr((struct sockaddr*) &sa); if (ret_src_address) { AvahiAddress a; avahi_address_from_sockaddr((struct sockaddr*) &sa, &a); *ret_src_address = a.data.ipv6; } for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) { if (cmsg->cmsg_level == IPPROTO_IPV6) { switch (cmsg->cmsg_type) { case IPV6_HOPLIMIT: if (ret_ttl) *ret_ttl = (uint8_t) (*(int *) CMSG_DATA(cmsg)); found_ttl = 1; break; case IPV6_PKTINFO: { struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg); if (ret_iface) *ret_iface = i->ipi6_ifindex; if (ret_dst_address) memcpy(ret_dst_address->address, i->ipi6_addr.s6_addr, 16); found_iface = 1; break; } default: avahi_log_warn("Unhandled cmsg_type : %d", cmsg->cmsg_type); break; } } } assert(found_iface); assert(found_ttl); return p; fail: if (p) avahi_dns_packet_free(p); return NULL; }
AvahiDnsPacket *avahi_recv_dns_packet_ipv4( int fd, AvahiIPv4Address *ret_src_address, uint16_t *ret_src_port, AvahiIPv4Address *ret_dst_address, AvahiIfIndex *ret_iface, uint8_t *ret_ttl) { AvahiDnsPacket *p= NULL; struct msghdr msg; struct iovec io; size_t aux[1024 / sizeof(size_t)]; /* for alignment on ia64 ! */ ssize_t l; struct cmsghdr *cmsg; int found_addr = 0; int ms; struct sockaddr_in sa; assert(fd >= 0); if (ioctl(fd, FIONREAD, &ms) < 0) { avahi_log_warn("ioctl(): %s", strerror(errno)); goto fail; } if (ms < 0) { avahi_log_warn("FIONREAD returned negative value."); goto fail; } p = avahi_dns_packet_new(ms + AVAHI_DNS_PACKET_EXTRA_SIZE); io.iov_base = AVAHI_DNS_PACKET_DATA(p); io.iov_len = p->max_size; memset(&msg, 0, sizeof(msg)); msg.msg_name = &sa; msg.msg_namelen = sizeof(sa); msg.msg_iov = &io; msg.msg_iovlen = 1; msg.msg_control = aux; msg.msg_controllen = sizeof(aux); msg.msg_flags = 0; if ((l = recvmsg(fd, &msg, 0)) < 0) { /* Linux returns EAGAIN when an invalid IP packet has been received. We suppress warnings in this case because this might create quite a bit of log traffic on machines with unstable links. (See #60) */ if (errno != EAGAIN) avahi_log_warn("recvmsg(): %s", strerror(errno)); goto fail; } if (sa.sin_addr.s_addr == INADDR_ANY) { /* Linux 2.4 behaves very strangely sometimes! */ goto fail; } assert(!(msg.msg_flags & MSG_CTRUNC)); assert(!(msg.msg_flags & MSG_TRUNC)); p->size = (size_t) l; if (ret_src_port) *ret_src_port = avahi_port_from_sockaddr((struct sockaddr*) &sa); if (ret_src_address) { AvahiAddress a; avahi_address_from_sockaddr((struct sockaddr*) &sa, &a); *ret_src_address = a.data.ipv4; } if (ret_ttl) *ret_ttl = 255; if (ret_iface) *ret_iface = AVAHI_IF_UNSPEC; for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) { if (cmsg->cmsg_level == IPPROTO_IP) { switch (cmsg->cmsg_type) { #ifdef IP_RECVTTL case IP_RECVTTL: #endif case IP_TTL: if (ret_ttl) *ret_ttl = (uint8_t) (*(int *) CMSG_DATA(cmsg)); break; #ifdef IP_PKTINFO case IP_PKTINFO: { struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg); if (ret_iface) *ret_iface = (int) i->ipi_ifindex; if (ret_dst_address) ret_dst_address->address = i->ipi_addr.s_addr; found_addr = 1; break; } #endif #ifdef IP_RECVIF case IP_RECVIF: { struct sockaddr_dl *sdl = (struct sockaddr_dl *) CMSG_DATA (cmsg); if (ret_iface) #ifdef __sun *ret_iface = *(uint_t*) sdl; #else *ret_iface = (int) sdl->sdl_index; #endif break; } #endif #ifdef IP_RECVDSTADDR case IP_RECVDSTADDR: if (ret_dst_address) memcpy(&ret_dst_address->address, CMSG_DATA (cmsg), 4); found_addr = 1; break; #endif default: avahi_log_warn("Unhandled cmsg_type : %d", cmsg->cmsg_type); break; } } } assert(found_addr); return p; fail: if (p) avahi_dns_packet_free(p); return NULL; }