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Clementine-audio-player-Mac.../3rdparty/tinysvcmdns/mdnsd.c

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/*
* tinysvcmdns - a tiny MDNS implementation for publishing services
* Copyright (C) 2011 Darell Tan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef _WIN32
#include <winsock2.h>
#include <ws2tcpip.h>
#define LOG_ERR 3
#else
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <syslog.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <assert.h>
#include <pthread.h>
/*
* Define a proper IP socket level if not already done.
* Required to compile on OS X
*/
#ifndef SOL_IP
#define SOL_IP IPPROTO_IP
#endif
#include "mdns.h"
#include "mdnsd.h"
#define MDNS_ADDR "224.0.0.251"
#define MDNS_PORT 5353
#define PACKET_SIZE 65536
#define SERVICES_DNS_SD_NLABEL \
((uint8_t *) "\x09_services\x07_dns-sd\x04_udp\x05local")
struct mdnsd {
pthread_mutex_t data_lock;
int sockfd;
int notify_pipe[2];
int stop_flag;
struct rr_group *group;
struct rr_list *announce;
struct rr_list *services;
uint8_t *hostname;
};
struct mdns_service {
struct rr_list *entries;
};
/////////////////////////////////
static void log_message(int loglevel, char *fmt_str, ...) {
va_list ap;
char buf[2048];
va_start(ap, fmt_str);
vsnprintf(buf, 2047, fmt_str, ap);
va_end(ap);
buf[2047] = 0;
fprintf(stderr, "%s\n", buf);
}
static int create_recv_sock(uint32_t bind_ip) {
int sd = socket(AF_INET, SOCK_DGRAM, 0);
if (sd < 0) {
log_message(LOG_ERR, "recv socket(): %m");
return sd;
}
int r = -1;
int on = 1;
if ((r = setsockopt(sd, SOL_SOCKET, SO_REUSEADDR, (char *) &on, sizeof(on))) < 0) {
log_message(LOG_ERR, "recv setsockopt(SO_REUSEADDR): %m");
return r;
}
/* bind to an address */
struct sockaddr_in serveraddr;
memset(&serveraddr, 0, sizeof(serveraddr));
serveraddr.sin_family = AF_INET;
serveraddr.sin_port = htons(MDNS_PORT);
serveraddr.sin_addr.s_addr = bind_ip; /* receive multicast */
if ((r = bind(sd, (struct sockaddr *)&serveraddr, sizeof(serveraddr))) < 0) {
log_message(LOG_ERR, "recv bind(): %m");
}
// add membership to receiving socket
struct ip_mreq mreq;
memset(&mreq, 0, sizeof(struct ip_mreq));
mreq.imr_interface.s_addr = htonl(INADDR_ANY);
mreq.imr_multiaddr.s_addr = inet_addr(MDNS_ADDR);
if ((r = setsockopt(sd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *) &mreq, sizeof(mreq))) < 0) {
log_message(LOG_ERR, "recv setsockopt(IP_ADD_MEMBERSHIP): %m");
return r;
}
// enable loopback in case someone else needs the data
if ((r = setsockopt(sd, IPPROTO_IP, IP_MULTICAST_LOOP, (char *) &on, sizeof(on))) < 0) {
log_message(LOG_ERR, "recv setsockopt(IP_MULTICAST_LOOP): %m");
return r;
}
#ifdef IP_PKTINFO
if ((r = setsockopt(sd, SOL_IP, IP_PKTINFO, (char *) &on, sizeof(on))) < 0) {
log_message(LOG_ERR, "recv setsockopt(IP_PKTINFO): %m");
return r;
}
#endif
return sd;
}
static ssize_t send_packet(int fd, const void *data, size_t len) {
static struct sockaddr_in toaddr;
if (toaddr.sin_family != AF_INET) {
memset(&toaddr, 0, sizeof(struct sockaddr_in));
toaddr.sin_family = AF_INET;
toaddr.sin_port = htons(MDNS_PORT);
toaddr.sin_addr.s_addr = inet_addr(MDNS_ADDR);
}
return sendto(fd, data, len, 0, (struct sockaddr *) &toaddr, sizeof(struct sockaddr_in));
}
// populate the specified list which matches the RR name and type
// type can be RR_ANY, which populates all entries EXCEPT RR_NSEC
static int populate_answers(struct mdnsd *svr, struct rr_list **rr_head, uint8_t *name, enum rr_type type) {
int num_ans = 0;
// check if we have the records
pthread_mutex_lock(&svr->data_lock);
struct rr_group *ans_grp = rr_group_find(svr->group, name);
if (ans_grp == NULL) {
pthread_mutex_unlock(&svr->data_lock);
return num_ans;
}
// decide which records should go into answers
struct rr_list *n = ans_grp->rr;
for (; n; n = n->next) {
// exclude NSEC for RR_ANY
if (type == RR_ANY && n->e->type == RR_NSEC)
continue;
if ((type == n->e->type || type == RR_ANY) && cmp_nlabel(name, n->e->name) == 0) {
num_ans += rr_list_append(rr_head, n->e);
}
}
pthread_mutex_unlock(&svr->data_lock);
return num_ans;
}
// given a list of RRs, look up related records and add them
static void add_related_rr(struct mdnsd *svr, struct rr_list *list, struct mdns_pkt *reply) {
for (; list; list = list->next) {
struct rr_entry *ans = list->e;
switch (ans->type) {
case RR_PTR:
// target host A, AAAA records
reply->num_add_rr += populate_answers(svr, &reply->rr_add,
MDNS_RR_GET_PTR_NAME(ans), RR_ANY);
break;
case RR_SRV:
// target host A, AAAA records
reply->num_add_rr += populate_answers(svr, &reply->rr_add,
ans->data.SRV.target, RR_ANY);
// perhaps TXT records of the same name?
// if we use RR_ANY, we risk pulling in the same RR_SRV
reply->num_add_rr += populate_answers(svr, &reply->rr_add,
ans->name, RR_TXT);
break;
case RR_A:
case RR_AAAA:
reply->num_add_rr += populate_answers(svr, &reply->rr_add,
ans->name, RR_NSEC);
break;
default:
// nothing to add
break;
}
}
}
// creates an announce packet given the type name PTR
static void announce_srv(struct mdnsd *svr, struct mdns_pkt *reply, uint8_t *name) {
mdns_init_reply(reply, 0);
reply->num_ans_rr += populate_answers(svr, &reply->rr_ans, name, RR_PTR);
// remember to add the services dns-sd PTR too
reply->num_ans_rr += populate_answers(svr, &reply->rr_ans,
SERVICES_DNS_SD_NLABEL, RR_PTR);
// see if we can match additional records for answers
add_related_rr(svr, reply->rr_ans, reply);
// additional records for additional records
add_related_rr(svr, reply->rr_add, reply);
}
// processes the incoming MDNS packet
// returns >0 if processed, 0 otherwise
static int process_mdns_pkt(struct mdnsd *svr, struct mdns_pkt *pkt, struct mdns_pkt *reply) {
int i;
assert(pkt != NULL);
// is it standard query?
if ((pkt->flags & MDNS_FLAG_RESP) == 0 &&
MDNS_FLAG_GET_OPCODE(pkt->flags) == 0) {
mdns_init_reply(reply, pkt->id);
DEBUG_PRINTF("flags = %04x, qn = %d, ans = %d, add = %d\n",
pkt->flags,
pkt->num_qn,
pkt->num_ans_rr,
pkt->num_add_rr);
// loop through questions
struct rr_list *qnl = pkt->rr_qn;
for (i = 0; i < pkt->num_qn; i++, qnl = qnl->next) {
struct rr_entry *qn = qnl->e;
int num_ans_added = 0;
char *namestr = nlabel_to_str(qn->name);
DEBUG_PRINTF("qn #%d: type %s (%02x) %s - ", i, rr_get_type_name(qn->type), qn->type, namestr);
free(namestr);
// check if it's a unicast query - we ignore those
if (qn->unicast_query) {
DEBUG_PRINTF("skipping unicast query\n");
continue;
}
num_ans_added = populate_answers(svr, &reply->rr_ans, qn->name, qn->type);
reply->num_ans_rr += num_ans_added;
DEBUG_PRINTF("added %d answers\n", num_ans_added);
}
// remove our replies if they were already in their answers
struct rr_list *ans = NULL, *prev_ans = NULL;
for (ans = reply->rr_ans; ans; ) {
struct rr_list *next_ans = ans->next;
struct rr_entry *known_ans = rr_entry_match(pkt->rr_ans, ans->e);
// discard answers that have at least half of the actual TTL
if (known_ans != NULL && known_ans->ttl >= ans->e->ttl / 2) {
char *namestr = nlabel_to_str(ans->e->name);
DEBUG_PRINTF("removing answer for %s\n", namestr);
free(namestr);
// check if list item is head
if (prev_ans == NULL)
reply->rr_ans = ans->next;
else
prev_ans->next = ans->next;
free(ans);
ans = prev_ans;
// adjust answer count
reply->num_ans_rr--;
}
prev_ans = ans;
ans = next_ans;
}
// see if we can match additional records for answers
add_related_rr(svr, reply->rr_ans, reply);
// additional records for additional records
add_related_rr(svr, reply->rr_add, reply);
DEBUG_PRINTF("\n");
return reply->num_ans_rr;
}
return 0;
}
int create_pipe(int handles[2]) {
#ifdef _WIN32
SOCKET sock = socket(AF_INET, SOCK_STREAM, 0);
if (sock == INVALID_SOCKET) {
return -1;
}
struct sockaddr_in serv_addr;
memset(&serv_addr, 0, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(0);
serv_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
if (bind(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == SOCKET_ERROR) {
closesocket(sock);
return -1;
}
if (listen(sock, 1) == SOCKET_ERROR) {
closesocket(sock);
return -1;
}
int len = sizeof(serv_addr);
if (getsockname(sock, (SOCKADDR*)&serv_addr, &len) == SOCKET_ERROR) {
closesocket(sock);
return -1;
}
if ((handles[1] = socket(PF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) {
closesocket(sock);
return -1;
}
if (connect(handles[1], (struct sockaddr*)&serv_addr, len) == SOCKET_ERROR) {
closesocket(sock);
return -1;
}
if ((handles[0] = accept(sock, (struct sockaddr*)&serv_addr, &len)) == INVALID_SOCKET) {
closesocket((SOCKET)handles[1]);
handles[1] = INVALID_SOCKET;
closesocket(sock);
return -1;
}
closesocket(sock);
return 0;
#else
return pipe(handles);
#endif
}
int read_pipe(int s, char* buf, int len) {
#ifdef _WIN32
int ret = recv(s, buf, len, 0);
if (ret < 0 && WSAGetLastError() == WSAECONNRESET) {
ret = 0;
}
return ret;
#else
return read(s, buf, len);
#endif
}
int write_pipe(int s, char* buf, int len) {
#ifdef _WIN32
return send(s, buf, len, 0);
#else
return write(s, buf, len);
#endif
}
// main loop to receive, process and send out MDNS replies
// also handles MDNS service announces
static void main_loop(struct mdnsd *svr) {
fd_set sockfd_set;
int max_fd = svr->sockfd;
char notify_buf[2]; // buffer for reading of notify_pipe
void *pkt_buffer = malloc(PACKET_SIZE);
if (svr->notify_pipe[0] > max_fd)
max_fd = svr->notify_pipe[0];
struct mdns_pkt *mdns_reply = malloc(sizeof(struct mdns_pkt));
memset(mdns_reply, 0, sizeof(struct mdns_pkt));
while (! svr->stop_flag) {
FD_ZERO(&sockfd_set);
FD_SET(svr->sockfd, &sockfd_set);
FD_SET(svr->notify_pipe[0], &sockfd_set);
select(max_fd + 1, &sockfd_set, NULL, NULL, NULL);
if (FD_ISSET(svr->notify_pipe[0], &sockfd_set)) {
// flush the notify_pipe
read_pipe(svr->notify_pipe[0], (char*)&notify_buf, 1);
} else if (FD_ISSET(svr->sockfd, &sockfd_set)) {
struct sockaddr_in fromaddr;
socklen_t sockaddr_size = sizeof(struct sockaddr_in);
ssize_t recvsize = recvfrom(svr->sockfd, pkt_buffer, PACKET_SIZE, 0,
(struct sockaddr *) &fromaddr, &sockaddr_size);
if (recvsize < 0) {
log_message(LOG_ERR, "recv(): %m");
}
DEBUG_PRINTF("data from=%s size=%ld\n", inet_ntoa(fromaddr.sin_addr), (long) recvsize);
struct mdns_pkt *mdns = mdns_parse_pkt(pkt_buffer, recvsize);
if (mdns != NULL) {
if (process_mdns_pkt(svr, mdns, mdns_reply)) {
size_t replylen = mdns_encode_pkt(mdns_reply, pkt_buffer, PACKET_SIZE);
send_packet(svr->sockfd, pkt_buffer, replylen);
} else if (mdns->num_qn == 0) {
DEBUG_PRINTF("(no questions in packet)\n\n");
}
mdns_pkt_destroy(mdns);
}
}
// send out announces
while (1) {
struct rr_entry *ann_e = NULL;
// extract from head of list
pthread_mutex_lock(&svr->data_lock);
if (svr->announce)
ann_e = rr_list_remove(&svr->announce, svr->announce->e);
pthread_mutex_unlock(&svr->data_lock);
if (! ann_e)
break;
char *namestr = nlabel_to_str(ann_e->name);
DEBUG_PRINTF("sending announce for %s\n", namestr);
free(namestr);
announce_srv(svr, mdns_reply, ann_e->name);
if (mdns_reply->num_ans_rr > 0) {
size_t replylen = mdns_encode_pkt(mdns_reply, pkt_buffer, PACKET_SIZE);
send_packet(svr->sockfd, pkt_buffer, replylen);
}
}
}
// main thread terminating. send out "goodbye packets" for services
mdns_init_reply(mdns_reply, 0);
pthread_mutex_lock(&svr->data_lock);
struct rr_list *svc_le = svr->services;
for (; svc_le; svc_le = svc_le->next) {
// set TTL to zero
svc_le->e->ttl = 0;
mdns_reply->num_ans_rr += rr_list_append(&mdns_reply->rr_ans, svc_le->e);
}
pthread_mutex_unlock(&svr->data_lock);
// send out packet
if (mdns_reply->num_ans_rr > 0) {
size_t replylen = mdns_encode_pkt(mdns_reply, pkt_buffer, PACKET_SIZE);
send_packet(svr->sockfd, pkt_buffer, replylen);
}
// destroy packet
mdns_init_reply(mdns_reply, 0);
free(mdns_reply);
free(pkt_buffer);
#ifdef _WIN32
closesocket(svr->sockfd);
#else
close(svr->sockfd);
#endif
svr->stop_flag = 2;
}
/////////////////////////////////////////////////////
void mdnsd_set_hostname(struct mdnsd *svr, const char *hostname, uint32_t ip) {
struct rr_entry *a_e = NULL,
*nsec_e = NULL;
// currently can't be called twice
// dont ask me what happens if the IP changes
assert(svr->hostname == NULL);
a_e = rr_create_a(create_nlabel(hostname), ip);
nsec_e = rr_create(create_nlabel(hostname), RR_NSEC);
rr_set_nsec(nsec_e, RR_A);
pthread_mutex_lock(&svr->data_lock);
svr->hostname = create_nlabel(hostname);
rr_group_add(&svr->group, a_e);
rr_group_add(&svr->group, nsec_e);
pthread_mutex_unlock(&svr->data_lock);
}
void mdnsd_add_rr(struct mdnsd *svr, struct rr_entry *rr) {
pthread_mutex_lock(&svr->data_lock);
rr_group_add(&svr->group, rr);
pthread_mutex_unlock(&svr->data_lock);
}
struct mdns_service *mdnsd_register_svc(struct mdnsd *svr, const char *instance_name,
const char *type, uint16_t port, const char *hostname, const char *txt[]) {
struct rr_entry *txt_e = NULL,
*srv_e = NULL,
*ptr_e = NULL,
*bptr_e = NULL;
uint8_t *target;
uint8_t *inst_nlabel, *type_nlabel, *nlabel;
struct mdns_service *service = malloc(sizeof(struct mdns_service));
memset(service, 0, sizeof(struct mdns_service));
// combine service name
type_nlabel = create_nlabel(type);
inst_nlabel = create_nlabel(instance_name);
nlabel = join_nlabel(inst_nlabel, type_nlabel);
// create TXT record
if (txt && *txt) {
txt_e = rr_create(dup_nlabel(nlabel), RR_TXT);
rr_list_append(&service->entries, txt_e);
// add TXTs
for (; *txt; txt++)
rr_add_txt(txt_e, *txt);
}
// create SRV record
assert(hostname || svr->hostname); // either one as target
target = hostname ?
create_nlabel(hostname) :
dup_nlabel(svr->hostname);
srv_e = rr_create_srv(dup_nlabel(nlabel), port, target);
rr_list_append(&service->entries, srv_e);
// create PTR record for type
ptr_e = rr_create_ptr(type_nlabel, srv_e);
// create services PTR record for type
// this enables the type to show up as a "service"
bptr_e = rr_create_ptr(dup_nlabel(SERVICES_DNS_SD_NLABEL), ptr_e);
// modify lists here
pthread_mutex_lock(&svr->data_lock);
if (txt_e)
rr_group_add(&svr->group, txt_e);
rr_group_add(&svr->group, srv_e);
rr_group_add(&svr->group, ptr_e);
rr_group_add(&svr->group, bptr_e);
// append PTR entry to announce list
rr_list_append(&svr->announce, ptr_e);
rr_list_append(&svr->services, ptr_e);
pthread_mutex_unlock(&svr->data_lock);
// don't free type_nlabel - it's with the PTR record
free(nlabel);
free(inst_nlabel);
// notify server
write_pipe(svr->notify_pipe[1], ".", 1);
return service;
}
void mdns_service_destroy(struct mdns_service *srv) {
assert(srv != NULL);
rr_list_destroy(srv->entries, 0);
free(srv);
}
struct mdnsd *mdnsd_start() {
return mdnsd_start_bind(htonl(INADDR_ANY));
}
struct mdnsd *mdnsd_start_bind(uint32_t bind_ip) {
pthread_t tid;
pthread_attr_t attr;
struct mdnsd *server = malloc(sizeof(struct mdnsd));
memset(server, 0, sizeof(struct mdnsd));
if (create_pipe(server->notify_pipe) != 0) {
log_message(LOG_ERR, "pipe(): %m\n");
free(server);
return NULL;
}
server->sockfd = create_recv_sock(bind_ip);
if (server->sockfd < 0) {
log_message(LOG_ERR, "unable to create recv socket");
free(server);
return NULL;
}
pthread_mutex_init(&server->data_lock, NULL);
// init thread
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
if (pthread_create(&tid, &attr, (void *(*)(void *)) main_loop, (void *) server) != 0) {
pthread_mutex_destroy(&server->data_lock);
free(server);
return NULL;
}
return server;
}
void mdnsd_stop(struct mdnsd *s) {
assert(s != NULL);
struct timeval tv = {
.tv_sec = 0,
.tv_usec = 500 * 1000,
};
s->stop_flag = 1;
write_pipe(s->notify_pipe[1], ".", 1);
while (s->stop_flag != 2)
select(0, NULL, NULL, NULL, &tv);
#ifdef _WIN32
closesocket(s->notify_pipe[0]);
closesocket(s->notify_pipe[1]);
#else
close(s->notify_pipe[0]);
close(s->notify_pipe[1]);
#endif
pthread_mutex_destroy(&s->data_lock);
rr_group_destroy(s->group);
rr_list_destroy(s->announce, 0);
rr_list_destroy(s->services, 0);
if (s->hostname)
free(s->hostname);
free(s);
}
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