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/*
* Copyright © 2014-2015 VideoLabs SAS
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <microdns/microdns.h>
#include "compat.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
volatile sig_atomic_t sigflag = 0;
static void sighandler(int signum)
{
char s[] = "SIGINT received, exiting ...\n";
ssize_t result = write(fileno(stdout), s, sizeof(s));
(void)result;
sigflag = 1;
}
static bool stop(void *cbarg)
{
return (sigflag ? true : false);
}
static void callback(void *cbarg, const struct sockaddr *mdns_ip,
const char* service, enum mdns_announce_type type)
{
if ( service != NULL && strcmp( service, "_googlecast._tcp.local" ) )
return;
struct mdns_ctx *ctx = (struct mdns_ctx *) cbarg;
struct mdns_hdr hdr = {0};
struct rr_entry answers[4] = {{0}}; // A/AAAA, SRV, TXT, PTR
hdr.flags |= FLAG_QR;
hdr.flags |= FLAG_AA;
hdr.num_ans_rr = sizeof(answers) / sizeof(answers[0]);
for (int i = 0; i < hdr.num_ans_rr; i++)
{
answers[i].rr_class = RR_IN;
answers[i].ttl = type == MDNS_ANNOUNCE_GOODBYE ? 0 : 120;
answers[i].msbit = 1;
if (i + 1 < hdr.num_ans_rr)
answers[i].next = &answers[i + 1];
}
char domain_name[] = "mdnshost.local";
char service_type[] = "_googlecast._tcp.local";
// link service type (_googlecast._tcp) to our domain (mdnshost.local)
char service_type_link[] = "mdnshost mDNShost._googlecast._tcp.local";
// RR_PTR: point service type (_vlc._tcp._local) to local domain
answers[0].type = RR_PTR;
answers[0].name = service_type;
answers[0].data.PTR.domain = service_type_link;
// RR_TXT: provide additional information (HTTP server root directory etc.)
answers[1].type = RR_TXT;
answers[1].name = service_type_link;
// RR_SRV: provide info about the service we're announcing (port no, etc.)
answers[2].type = RR_SRV;
answers[2].name = service_type_link;
answers[2].data.SRV.port = 9001;
answers[2].data.SRV.priority = 0;
answers[2].data.SRV.weight = 0;
answers[2].data.SRV.target = domain_name;
// RR_A/AAAA: link .local domain to IP address
answers[3].name = domain_name;
if (mdns_ip->sa_family == AF_INET)
{
answers[3].type = RR_A;
memcpy(&answers[3].data.A.addr,
&((struct sockaddr_in*)mdns_ip)->sin_addr,
sizeof(answers[3].data.A.addr));
}
else
{
answers[3].type = RR_AAAA;
memcpy(&answers[3].data.AAAA.addr,
&((struct sockaddr_in6*)mdns_ip)->sin6_addr,
sizeof(answers[3].data.AAAA.addr));
}
mdns_entries_send(ctx, &hdr, answers);
}
int main(int argc, char *argv[])
{
int r = 0;
char err[128];
struct mdns_ctx *ctx;
signal(SIGINT, sighandler);
signal(SIGTERM, sighandler);
if ((r = mdns_init(&ctx, NULL, MDNS_PORT)) < 0)
goto err;
// test with `ping mdnshost.local` after discovery (run ./test first)
// NB: a zeroconf service (eg Avahi) must be running for ping to work
mdns_announce(ctx, RR_PTR, callback, ctx);
if ((r = mdns_serve(ctx, stop, NULL)) < 0)
goto err;
err:
if (r < 0) {
mdns_strerror(r, err, sizeof(err));
fprintf(stderr, "fatal: %s\n", err);
}
mdns_destroy(ctx);
return (0);
}
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