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mdnssd.c
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/*
mdnssd-min
mdnssd-min is a minimal DNS-SD and mDNS client that takes a service type
as its argument and returns the IPv4 and/or IPv6 addreses and port numbers
running a service of the type.
License: GPLv3
Author: [email protected]
Copyright 2013-2014 Marc Juul Christoffersen.
modifications by: [email protected]
References:
DNS RFC: http://tools.ietf.org/html/rfc1035
Section 4.1, 3.2.2 and 3.2.4
DNS RFC: http://tools.ietf.org/html/rfc1034
Section 3.7.1
DNS Security Extensions RFC: http://tools.ietf.org/html/rfc2535
Section 6.1
mDNS RFC: http://tools.ietf.org/html/rfc6762
Section 18.
DNS-SD RFC: http://tools.ietf.org/html/rfc6763
DNS SRV RFC: http://tools.ietf.org/html/rfc2782
*/
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <time.h>
#include "mdnssd.h"
#include "mdnssd-core.h"
#ifndef _WIN32
#include <sys/ioctl.h>
#include <net/if.h>
#endif
#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__)
#include <sys/time.h>
#endif
// is debug mode enabled?
static int debug_mode;
/*---------------------------------------------------------------------------*/
static int debug(const char* format, ...) {
va_list args;
int ret;
if(!debug_mode) {
return 0;
}
va_start(args, format);
ret = vfprintf(stderr, format, args);
va_end(args);
return ret;
}
/*---------------------------------------------------------------------------*/
static uint32_t gettime(void) {
#ifdef _WIN32
return GetTickCount64() / 1000;
#else
#if defined(__linux__) || defined(__FreeBSD__)
struct timespec ts;
if (!clock_gettime(CLOCK_MONOTONIC, &ts)) {
return ts.tv_sec;
}
#endif
struct timeval tv;
gettimeofday(&tv, NULL);
return tv.tv_sec;
#endif
}
/*---------------------------------------------------------------------------*/
static item_t *insert_item(item_t *item, item_t **list) {
if (*list) item->next = *list;
else item->next = NULL;
*list = item;
return item;
}
/*---------------------------------------------------------------------------*/
/*
static item_t *insert_tail_item(item_t *item, item_t **list) {
if (*list) {
struct item_s *p = *list;
while (p->next) p = p->next;
item->next = p->next;
p->next = item;
} else {
item->next = NULL;
*list = item;
}
return item;
}
*/
/*---------------------------------------------------------------------------*/
/*
static item_t *insert_ordered_item(item_t *item, item_t **list, int (*compare)(void *a, void *b)) {
if (*list) {
struct item_s *p = *list;
while (p->next && compare(p->next, item) <= 0) p = p->next;
item->next = p->next;
p->next = item;
} else {
item->next = NULL;
*list = item;
}
return item;
}
*/
/*---------------------------------------------------------------------------*/
static item_t *remove_item(item_t *item, item_t **list) {
if (item != *list) {
struct item_s *p = *list;
while (p && p->next != item) p = p->next;
if (p) p->next = item->next;
item->next = NULL;
} else *list = (*list)->next;
return item;
}
/*---------------------------------------------------------------------------*/
static void clear_list(item_t *list, void (*free_func)(void *)) {
if (!list) return;
while (list) {
struct item_s *next = list->next;
if (free_func) (*free_func)(list);
else free(list);
list = next;
}
}
/*---------------------------------------------------------------------------*/
static void free_a(alist_t* a) {
if (a->name) free(a->name);
free(a);
}
/*---------------------------------------------------------------------------*/
static void free_s(slist_t* s) {
if (s->name) free(s->name);
if (s->hostname) free(s->hostname);
if (s->txt) free(s->txt);
free(s);
}
/*---------------------------------------------------------------------------*/
static char* prepare_query_string(const char* name) {
int i;
int count;
int lastdot = 0;
int len = strlen(name);
char* result;
result = malloc(len + 2);
if(!result) {
debug("failed to allocate memory for parsed hostname");
return NULL;
}
count = 0;
for(i=0; i < len+1; i++) {
if((name[i] == '.') || (name[i] == '\0')) {
result[lastdot] = (char) count;
count = 0;
lastdot = i+1;
continue;
}
result[i+1] = name[i];
count++;
}
result[len+1] = '\0';
return result;
}
// expects host byte_order
/*---------------------------------------------------------------------------*/
static mDNSFlags* mdns_parse_header_flags(uint16_t data) {
mDNSFlags* flags = malloc(sizeof(mDNSFlags));
if(!flags) {
debug("could not allocate memory for parsing header flags");
return NULL;
}
flags->rcode = data & 0xf;
flags->cd = (data >> 4) & 1;
flags->ad = (data >> 5) & 1;
flags->zero = (data >> 6) & 1;
flags->ra = (data >> 7) & 1;
flags->rd = (data >> 8) & 1;
flags->tc = (data >> 9) & 1;
flags->aa = (data >> 10) & 1;
flags->opcode = (data >> 14) & 0xf;
flags->qr = (data >> 15) & 1;
return flags;
}
// outputs host byte order
/*---------------------------------------------------------------------------*/
static uint16_t mdns_pack_header_flags(mDNSFlags flags) {
uint16_t packed = 0;
packed |= (flags.rcode & 0xfff0);
packed |= (flags.cd & 0xfffe) << 4;
packed |= (flags.ad & 0xfffe) << 5;
packed |= (flags.zero & 0xfffe) << 6;
packed |= (flags.ra & 0xfffe) << 7;
packed |= (flags.rd & 0xfffe) << 8;
packed |= (flags.tc & 0xfffe) << 9;
packed |= (flags.aa & 0xfffe) << 10;
packed |= (flags.opcode & 0xfff0) << 14;
packed |= (flags.qr & 0xfffe) << 15;
return packed;
}
/*---------------------------------------------------------------------------*/
static char* mdns_pack_question(mDNSQuestion* q, size_t* size) {
char* packed;
size_t name_length;
uint16_t qtype;
uint16_t qclass;
name_length = strlen(q->qname) + 1;
if(name_length > DNS_MAX_HOSTNAME_LENGTH) {
debug("domain name too long");
return NULL;
}
debug("name length: %u\n", name_length);
*size = name_length + 2 + 2;
// 1 char for terminating \0, 2 for qtype and 2 for qclass
packed = malloc(*size);
if(!packed) {
debug("could not allocate memory for DNS question");
return NULL;
}
memcpy(packed, q->qname, name_length);
// The top bit of the qclass field is repurposed by mDNS
// to indicate that a unicast response is preferred
// See RFC 6762 section 5.4
if(q->prefer_unicast_response) {
q->qclass |= 1 << 15;
}
qtype = htons(q->qtype);
qclass = htons(q->qclass);
memcpy(packed + name_length, &qtype, 2);
memcpy(packed + name_length + 2, &qclass, 2);
return packed;
}
// parse question section
/*---------------------------------------------------------------------------*/
static int mdns_parse_question(char* message, char* data, int size) {
mDNSQuestion q;
char* cur;
int parsed = 0;
cur = data;
// TODO check for invalid length
q.qname = parse_rr_name(message, data, &parsed);
free(q.qname);
cur += parsed;
if(parsed > size) {
debug("qname is too long");
return 0;
}
memcpy(&(q.qtype), cur, 2);
q.qtype = ntohs(q.qtype);
cur += 2;
parsed += 2;
if(parsed > size) {
return 0;
}
memcpy(&(q.qclass), cur, 2);
q.qclass = ntohs(q.qclass);
cur += 2;
parsed += 2;
if(parsed > size) {
return 0;
}
return parsed;
}
/*---------------------------------------------------------------------------*/
static void mdns_message_print(mDNSMessage* msg) {
mDNSFlags* flags = mdns_parse_header_flags(msg->flags);
if (!flags) return;
/*
debug("ID: %u\n", msg->id);
debug("Flags: \n");
debug(" QR: %u\n", flags->qr);
debug(" OPCODE: %u\n", flags->opcode);
debug(" AA: %u\n", flags->aa);
debug(" TC: %u\n", flags->tc);
debug(" RD: %u\n", flags->rd);
debug(" RA: %u\n", flags->ra);
debug(" Z: %u\n", flags->zero);
debug(" AD: %u\n", flags->ad);
debug(" CD: %u\n", flags->cd);
debug(" RCODE: %u\n", flags->rcode);
debug("\n");
debug("QDCOUNT: %u\n", msg->qd_count);
debug("ANCOUNT: %u\n", msg->an_count);
debug("NSCOUNT: %u\n", msg->ns_count);
debug("ARCOUNT: %u\n", msg->ar_count);
debug("Resource records:\n");
*/
free(flags);
}
// parse A resource record
/*---------------------------------------------------------------------------*/
static int mdns_parse_rr_a(char* data, struct in_addr *addr) {
addr->s_addr = INADDR_ANY;
// ignore local link responses
if ((data[0] == '\xa9') && (data[1] == '\xfe')) return 4;
memcpy(&(addr->s_addr), data, 4);
debug(" A: %s\n", inet_ntoa(*addr));
return 4;
}
// parse PTR resource record
/*---------------------------------------------------------------------------*/
static int mdns_parse_rr_ptr(char* message, char* data, char **name) {
int parsed = 0;
*name = parse_rr_name(message, data, &parsed);
debug(" PTR: %s\n", *name);
return parsed;
}
// parse SRV resource record
/*---------------------------------------------------------------------------*/
static int mdns_parse_rr_srv(char* message, char* data, char **hostname, unsigned short *port) {
uint16_t priority;
uint16_t weight;
int parsed = 0;
// TODO currently we do nothing with the priority and weight
memcpy(&priority, data, 2);
priority = ntohs(priority);
data += 2;
parsed += 2;
memcpy(&weight, data, 2);
weight = ntohs(weight);
data += 2;
parsed += 2;
memcpy(port, data, 2);
*port = ntohs(*port);
data += 2;
parsed += 2;
*hostname = parse_rr_name(message, data, &parsed);
debug(" SRV target: %s\n", *hostname);
debug(" SRV port: %u\n", *port);
return parsed;
}
// parse TXT resource record
/*---------------------------------------------------------------------------*/
static void mdns_parse_rr_txt(char* message, mDNSResourceRecord* rr, char**txt, int *length) {
if ((*txt = malloc(rr->rdata_length)) != NULL) {
memcpy(*txt, rr->rdata, rr->rdata_length);
*length = rr->rdata_length;
}
}
// get name compression offset
/*---------------------------------------------------------------------------*/
static uint16_t get_offset(char* data) {
uint16_t offset;
memcpy(&offset, data, 2);
offset = ntohs(offset);
if((offset >> 14) & 3) {
// this means that the name is a reference to
// a string instead of a string
offset &= 0x3fff; // change two most significant bits to 0
return offset;
}
return 0;
};
// parse a domain name
// of the type included in resource records
/*---------------------------------------------------------------------------*/
static char* parse_rr_name(char* message, char* name, int* parsed) {
int dereference_count = 0;
uint16_t offset;
int label_len;
char* out;
int out_i = 0;
int i = 0;
int did_jump = 0;
int pars = 0;
out = malloc(MAX_RR_NAME_SIZE);
if(!out) {
debug("could not allocate memory for resource record name");
return NULL;
}
while(1) {
offset = get_offset(name);
if(offset) {
if(!did_jump) {
pars += 2; // parsed two bytes before jump
}
did_jump = 1;
name = message + offset;
dereference_count++;
if(dereference_count >= MAX_DEREFERENCE_COUNT) {
// don't allow messages to crash this app
free(out);
return NULL;
}
continue;
}
// insert a dot between labels
if(out_i > 0) {
out[out_i++] = '.';
if(out_i+1 >= MAX_RR_NAME_SIZE) {
free(out);
return NULL;
}
}
// it wasn't an offset, so it must be a string length
label_len = (int) name[0];
name++;
if(!did_jump) {
pars++;
}
for(i=0; i < label_len; i++) {
out[out_i++] = name[i];
if(out_i+1 >= MAX_RR_NAME_SIZE) {
free(out);
return NULL;
}
if(!did_jump) {
pars++;
}
}
name += label_len;
if(name[0] == '\0') {
out[out_i] = '\0';
if(!did_jump && label_len) {
pars++;
}
*parsed += pars;
return out;
}
}
}
/*---------------------------------------------------------------------------*/
static void free_resource_record(mDNSResourceRecord* rr) {
if(rr->name) {
free(rr->name);
rr->name = NULL;
}
}
// parse a resource record
// the answer, authority and additional sections all use the resource record format
/*---------------------------------------------------------------------------*/
static int mdns_parse_rr(struct in_addr host, struct context_s *context, char* message, char* rrdata, int size, int is_answer) {
mDNSResourceRecord rr;
int parsed = 0;
char* cur = rrdata;
rr.name = NULL;
rr.name = parse_rr_name(message, rrdata, &parsed);
if(!rr.name) {
// TODO are calling functions dealing with this correctly?
free_resource_record(&rr);
debug("parsing resource record name failed\n");
return 0;
}
cur += parsed;
// +10 because type, class, ttl and rdata_lenth
// take up total 10 bytes
if(parsed+10 > size) {
free_resource_record(&rr);
return 0;
}
debug(" Resource Record Name: %s\n", rr.name);
memcpy(&(rr.type), cur, 2);
rr.type = ntohs(rr.type);
cur += 2;
parsed += 2;
debug(" Resource Record Type: %u\n", rr.type);
memcpy(&(rr.class), cur, 2);
rr.class = ntohs(rr.class);
cur += 2;
parsed += 2;
memcpy(&(rr.ttl), cur, 4);
rr.ttl = ntohl(rr.ttl);
cur += 4;
parsed += 4;
debug(" ttl: %u\n", rr.ttl);
memcpy(&(rr.rdata_length), cur, 2);
rr.rdata_length = ntohs(rr.rdata_length);
cur += 2;
parsed += 2;
if(parsed > size) {
free_resource_record(&rr);
return 0;
}
rr.rdata = cur;
parsed += rr.rdata_length;
if (is_answer) {
if (rr.type == DNS_RR_TYPE_A) store_a(context, &rr);
else store_other(host, context, message, &rr);
}
free_resource_record(&rr);
debug(" ------------------------------\n");
return parsed;
}
// TODO this only parses the header so far
/*---------------------------------------------------------------------------*/
static int mdns_parse_message_net(struct in_addr host, struct context_s *context, char* data, int size, mDNSMessage* msg) {
int parsed = 0;
int i;
if(size < DNS_HEADER_SIZE) {
return 0;
}
memcpy(msg, data, DNS_HEADER_SIZE);
msg->id = ntohs(msg->id);
msg->flags = ntohs(msg->flags);
msg->qd_count = ntohs(msg->qd_count);
msg->an_count = ntohs(msg->an_count);
msg->ns_count = ntohs(msg->ns_count);
msg->ar_count = ntohs(msg->ar_count);
parsed += DNS_HEADER_SIZE;
mdns_message_print(msg);
debug(" Question records [%u] (not shown)\n", msg->qd_count);
for(i=0; i < msg->qd_count; i++) {
parsed += mdns_parse_question(data, data+parsed, size-parsed);
}
debug(" Answer records [%u]\n", msg->an_count);
for(i=0; i < msg->an_count; i++) {
parsed += mdns_parse_rr(host, context, data, data+parsed, size-parsed, 1);
}
debug(" Nameserver records [%u] (not shown)\n", msg->ns_count);
for(i=0; i < msg->ns_count; i++) {
parsed += mdns_parse_rr(host, context, data, data+parsed, size-parsed, 0);
}
debug(" Additional records [%u] (not shown)\n", msg->ns_count);
for(i=0; i < msg->ar_count; i++) {
parsed += mdns_parse_rr(host, context, data, data+parsed, size-parsed, 1);
}
return parsed;
}
/*---------------------------------------------------------------------------*/
static mDNSMessage* mdns_build_query_message(char* query_str, uint16_t query_type, bool unicast) {
mDNSMessage* msg;
mDNSQuestion question;
mDNSFlags flags;
msg = malloc(sizeof(mDNSMessage));
if(!msg) {
debug("failed to allocate memory for mDNS message");
return NULL;
}
flags.qr = 0; // this is a query
flags.opcode = 0; // opcode must be 0 for multicast
flags.aa = 0; // must be 0 for queries
flags.tc = 0; // no (more) known-answer records coming
flags.rd = 0; // must be 0 for multicast
flags.ra = 0; // must be 0 for multicast
flags.zero = 0; // must be zero
flags.ad = 0; // must be zero for multicast
flags.cd = 0; // must be zero for multicast
flags.rcode = 0;
msg->id = 0; // should be 0 for multicast query messages
msg->flags = htons(mdns_pack_header_flags(flags));
msg->qd_count = htons(1); // one question
msg->an_count = msg->ns_count = msg->ar_count = 0;
question.qname = query_str;
if(!question.qname) {
return NULL;
}
question.prefer_unicast_response = unicast;
question.qtype = query_type;
question.qclass = 1; // class for the internet (RFC 1035 section 3.2.4) but ask for unicast
if ((msg->data = mdns_pack_question(&question, &(msg->data_size))) == NULL) {
free(msg);
return NULL;
}
return msg;
}
/*---------------------------------------------------------------------------*/
static char* mdns_pack_message(mDNSMessage* msg, size_t* pack_length) {
char* pack;
*pack_length = DNS_HEADER_SIZE + msg->data_size;
if(*pack_length > DNS_MESSAGE_MAX_SIZE) {
debug("mDNS message too large");
return NULL;
}
pack = malloc(*pack_length);
if(!pack) {
debug("failed to allocate data for packed mDNS message");
return NULL;
}
memcpy(pack, msg, DNS_HEADER_SIZE);
memcpy(pack + DNS_HEADER_SIZE, msg->data, msg->data_size);
return pack;
}
// parse TXT resource record
/*---------------------------------------------------------------------------*/
static void mdns_parse_txt(char *txt, int txt_length, mdnssd_service_t *s) {
int len = 0, count = 0;
char *p;
int i;
if (!txt) return;
while (len + count < txt_length) {
len += * ((char*) txt + len + count);
count++;
}
s->attr_count = count;
s->attr = malloc(count * sizeof(mdnssd_txt_attr_t));
p = txt;
for (i = 0; i < count; i++) {
char *value = memchr(p + 1, '=', *p);
if (value) {
len = *p - (value - (p + 1)) - 1;
s->attr[i].value = malloc(len + 1);
memcpy(s->attr[i].value, value + 1, len);
s->attr[i].value[len] = '\0';
len = (value - (p + 1));
s->attr[i].name = malloc(len + 1);
memcpy(s->attr[i].name, p + 1, len);
s->attr[i].name[len] = '\0';
}
else {
len = *p;
s->attr[i].name = malloc(len + 1);
memcpy(s->attr[i].name, p + 1, len);
s->attr[i].name[len] = '\0';
s->attr[i].value = NULL;
}
p += *p + 1;
}
}
/*---------------------------------------------------------------------------*/
static int send_query(int sock, const char* query_arg, uint16_t query_type, bool unicast) {
mDNSMessage* msg;
char* data;
size_t data_size;
int res;
struct sockaddr_in addr;
socklen_t addrlen;
char* query_str;
if ((query_str = prepare_query_string(query_arg)) == NULL) return -1;
addr.sin_family = AF_INET;
addr.sin_port = htons(MDNS_PORT);
addr.sin_addr.s_addr = inet_addr(MDNS_MULTICAST_ADDRESS);
addrlen = sizeof(addr);
// build and pack the query message
msg = mdns_build_query_message(query_str, query_type, unicast);
free(query_str);
if (!msg) return -1;
data = mdns_pack_message(msg, &data_size);
free(msg->data);
free(msg);
if (!data) return -1;
debug("Sending DNS message with length: %u\n", data_size);
// send query message
res = sendto(sock, data, data_size, 0, (struct sockaddr *) &addr, addrlen);
free(data);
return res;
}
/*
An answer is complete if it has all of:
* A hostname (from a SRV record)
* A port (from a SRV record)
* An IP address (from an A record)
*/
/*---------------------------------------------------------------------------*/
static int is_complete(slist_t *s) {
if (s->addr.s_addr && s->hostname && s->port && s->txt) return 1;
else return 0;
}
/*---------------------------------------------------------------------------*/
static void store_a(struct context_s *context, mDNSResourceRecord* rr) {
alist_t *b;
struct in_addr addr;
mdns_parse_rr_a(rr->rdata, &addr);
for (b = context->alist; b; b = b->next) {
if (!strcmp(b->name, rr->name)) {
if (addr.s_addr) b->addr = addr;
b->rr.ttl = rr->ttl;
b->rr.last = gettime();
return;
}
}
b = malloc(sizeof(alist_t));
b->addr = addr;
b->name = strdup(rr->name);
b->rr.ttl = rr->ttl;
b->rr.last = gettime();
insert_item((item_t*) b, (item_t**) &context->alist);
}
/*---------------------------------------------------------------------------*/
static slist_t *create_s(struct in_addr host, char *name, slist_t **list) {
slist_t *s = calloc(1, sizeof(slist_t));
s->name = strdup(name);
s->host = host;
insert_item((item_t*) s, (item_t**) list);
return s;
}
/*---------------------------------------------------------------------------*/
static void store_other(struct in_addr host, struct context_s *context, char *message, mDNSResourceRecord* rr) {
slist_t *b = NULL;
char *name = NULL;
uint32_t now;
// for a PTR, the rr name must match exactly the query, for others it shall
// at least contain it, otherwise it's not for us
if ((rr->type == DNS_RR_TYPE_PTR && strcmp(rr->name, context->query)) ||
!strstr(rr->name, context->query)) return;
now = gettime();
// the queuing tool is head insertion, so this reverts the time or arrival
// entry with ttl = 0 are not created, deletion must apply to an existing one
switch (rr->type) {
// PTR: get service name
case DNS_RR_TYPE_PTR: {
mdns_parse_rr_ptr(message, rr->rdata, &name);
// can't factorize the "for/switch" as name is updated above
for (b = context->slist; b && (strcmp(b->name, name) || b->host.s_addr != host.s_addr); b = b->next)
if (!b && rr->ttl) b = create_s(host, name, &context->slist);
if (b) {
b->rr_ptr.last = now;
b->rr_ptr.ttl = rr->ttl;
}
free(name);
break;
}
// SRV: service descriptor ==> get hostname & port
case DNS_RR_TYPE_SRV: {
unsigned short port;
char *hostname = NULL;
mdns_parse_rr_srv(message, rr->rdata, &hostname, &port);
for (b = context->slist; b && (strcmp(b->name, rr->name) || b->host.s_addr != host.s_addr); b = b->next);
if (!b && rr->ttl) b = create_s(host, rr->name, &context->slist);
if (b) {
// update port
if (port && b->port != port) {
b->port = port;
b->status = MDNS_UPDATED;
}
// update hostname
if (!b->hostname || strcmp(b->hostname, hostname)) {
NFREE(b->hostname);
b->status = MDNS_UPDATED;
b->hostname = strdup(hostname);
}
b->rr_srv.last = now;
b->rr_srv.ttl = rr->ttl;
}
free(hostname);
break;
}
// TXT: get txt content
case DNS_RR_TYPE_TXT: {
char *txt = NULL;
int length = 0;
mdns_parse_rr_txt(message, rr, &txt, &length);
for (b = context->slist; b && (strcmp(b->name, rr->name) || b->host.s_addr != host.s_addr); b = b->next);
if (!b && rr->ttl) b = create_s(host, rr->name, &context->slist);
if (b) {
// update txt
if (!b->txt || memcmp(b->txt, txt, length)) {
NFREE(b->txt);
b->txt = malloc(length);
b->txt_length = length;
memcpy(b->txt, txt, length);
b->status = MDNS_UPDATED;
}
b->rr_txt.last = now;
b->rr_txt.ttl = rr->ttl;
}
free(txt);
break;
}
}
}
/*---------------------------------------------------------------------------*/
static void update_wake_rr(uint32_t* wake, uint32_t now, struct ttl_timing_s* t) {
double retries[] = { 0.5, 0.8, 0.9, 0.95 };
// rr not current, don't participate to bid
if (!t->last) return;
// apply RFC6762 retries timeouts
for (int i = 0; i < 4; i++) {
uint32_t to = t->last + (uint32_t)(t->ttl * retries[i]);
if (now <= to) {
if (*wake > to) *wake = to;
t->wake = to;
break;
}
}
}
/*---------------------------------------------------------------------------*/
static void update_wake(struct context_s* context, uint32_t *wake, uint32_t now) {
for (slist_t* s = context->slist; s; s = s->next) {
if (s && s->status != MDNS_CURRENT) continue;
update_wake_rr(wake, now, &s->rr_ptr);
update_wake_rr(wake, now, &s->rr_srv);
update_wake_rr(wake, now, &s->rr_txt);
}
/*
for (alist_t* a = context->alist; a; a = a->next) {
update_wake_rr(wake, now, &a->rr);
}
*/
}
/*---------------------------------------------------------------------------*/
static bool check_query(struct context_s* context, uint32_t now) {
// if there is nothign in the service list, we must launcha query
if (!context->slist || !context->alist) return true;
// check to see if some services have reached their query time
for (slist_t* s = context->slist; s; s = s->next) {
if (s && s->status != MDNS_CURRENT) continue;
if (now >= s->rr_ptr.wake || now >= s->rr_srv.wake || now >= s->rr_txt.wake) return true;
}
/*
for (alist_t* a = context->alist; a; a = a->next) {
if (now >= a->rr.wake) return true;
}
*/