mirror of
https://github.com/owntone/owntone-server.git
synced 2025-01-14 00:05:03 -05:00
Perform manual hostname resolution by browsing mDNS RRs
The service resolver delivers a single IP address that doesn't always suit our needs. To get all the addresses advertised, we have to look at the RRs through the record browser; we can then apply our filters and extract the addresses that fit.
This commit is contained in:
Julien BLACHE
parent
2f2582800e
commit
4f59533ccb
324
src/mdns_avahi.c
324
src/mdns_avahi.c
@ -1,7 +1,7 @@
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/*
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* Avahi mDNS backend, with libevent polling
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*
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* Copyright (C) 2009-2010 Julien BLACHE <jb@jblache.org>
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* Copyright (C) 2009-2011 Julien BLACHE <jb@jblache.org>
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*
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* Pieces coming from mt-daapd:
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* Copyright (C) 2005 Sebastian Dröge <slomo@ubuntu.com>
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@ -28,6 +28,7 @@
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <sys/socket.h>
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#include <arpa/inet.h>
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#include <net/if.h>
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@ -307,7 +308,7 @@ static struct AvahiPoll ev_poll_api =
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};
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/* Avahi client callbacks & helpers (imported from mt-daapd) */
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/* Avahi client callbacks & helpers */
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struct mdns_browser
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{
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@ -317,6 +318,16 @@ struct mdns_browser
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struct mdns_browser *next;
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};
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struct mdns_record_browser {
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struct mdns_browser *mb;
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char *name;
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char *domain;
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struct keyval txt_kv;
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unsigned short port;
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};
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struct mdns_group_entry
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{
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char *name;
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@ -337,27 +348,171 @@ static struct mdns_group_entry *group_entries;
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#define IPV6LL_NETMASK 0xFFC0
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static int
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is_link_local(const AvahiAddress *addr)
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is_v4ll(struct in_addr *addr)
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{
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uint32_t a;
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return ((ntohl(addr->s_addr) & IPV4LL_NETMASK) == IPV4LL_NETWORK);
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}
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switch (addr->proto)
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static int
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is_v6ll(struct in6_addr *addr)
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{
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return ((((addr->s6_addr[0] << 8) | addr->s6_addr[1]) & IPV6LL_NETMASK) == IPV6LL_NETWORK);
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}
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static void
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browse_record_callback_v4(AvahiRecordBrowser *b, AvahiIfIndex intf, AvahiProtocol proto,
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AvahiBrowserEvent event, const char *hostname, uint16_t clazz, uint16_t type,
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const void *rdata, size_t size, AvahiLookupResultFlags flags, void *userdata)
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{
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char address[INET_ADDRSTRLEN];
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struct in_addr addr;
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struct mdns_record_browser *rb_data;
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rb_data = (struct mdns_record_browser *)userdata;
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switch (event)
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{
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case AVAHI_PROTO_INET:
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a = ntohl(addr->data.ipv4.address);
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case AVAHI_BROWSER_NEW:
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if (size != sizeof(addr.s_addr))
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{
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DPRINTF(E_WARN, L_MDNS, "Got RR type A size %ld (should be %ld)\n", (long)size, (long)sizeof(addr.s_addr));
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return (a & IPV4LL_NETMASK) == IPV4LL_NETWORK;
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return;
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}
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case AVAHI_PROTO_INET6:
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a = (addr->data.ipv6.address[0] << 8) | addr->data.ipv6.address[1];
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memcpy(&addr.s_addr, rdata, sizeof(addr.s_addr));
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return (a & IPV6LL_NETMASK) == IPV6LL_NETWORK;
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if (is_v4ll(&addr))
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{
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DPRINTF(E_DBG, L_MDNS, "Discarding IPv4 LL address\n");
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default:
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return 0;
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return;
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}
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if (!inet_ntop(AF_INET, &addr.s_addr, address, sizeof(address)))
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{
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DPRINTF(E_LOG, L_MDNS, "Could not print IPv4 address: %s\n", strerror(errno));
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return;
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}
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DPRINTF(E_DBG, L_MDNS, "Service %s, hostname %s resolved to %s\n", rb_data->name, hostname, address);
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/* Execute callback (mb->cb) with all the data */
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rb_data->mb->cb(rb_data->name, rb_data->mb->type, rb_data->domain, hostname, AF_INET, address, rb_data->port, &rb_data->txt_kv);
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/* Got a suitable address, stop record browser */
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break;
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case AVAHI_BROWSER_REMOVE:
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/* Not handled - record browser lifetime too short for this to happen */
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return;
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case AVAHI_BROWSER_CACHE_EXHAUSTED:
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case AVAHI_BROWSER_ALL_FOR_NOW:
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DPRINTF(E_DBG, L_MDNS, "Avahi Record Browser (%s v4): no more results (%s)\n", hostname,
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(event == AVAHI_BROWSER_CACHE_EXHAUSTED) ? "CACHE_EXHAUSTED" : "ALL_FOR_NOW");
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break;
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case AVAHI_BROWSER_FAILURE:
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DPRINTF(E_LOG, L_MDNS, "Avahi Record Browser (%s v4) failure: %s\n", hostname,
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avahi_strerror(avahi_client_errno(avahi_record_browser_get_client(b))));
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break;
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}
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return 0;
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keyval_clear(&rb_data->txt_kv);
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free(rb_data->name);
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free(rb_data->domain);
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free(rb_data);
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avahi_record_browser_free(b);
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}
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static void
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browse_record_callback_v6(AvahiRecordBrowser *b, AvahiIfIndex intf, AvahiProtocol proto,
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AvahiBrowserEvent event, const char *hostname, uint16_t clazz, uint16_t type,
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const void *rdata, size_t size, AvahiLookupResultFlags flags, void *userdata)
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{
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char address[INET6_ADDRSTRLEN + IF_NAMESIZE + 1];
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char ifname[IF_NAMESIZE];
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struct in6_addr addr;
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struct mdns_record_browser *rb_data;
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int len;
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int ret;
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rb_data = (struct mdns_record_browser *)userdata;
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switch (event)
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{
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case AVAHI_BROWSER_NEW:
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if (size != sizeof(addr.s6_addr))
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{
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DPRINTF(E_WARN, L_MDNS, "Got RR type AAAA size %ld (should be %ld)\n", (long)size, (long)sizeof(addr.s6_addr));
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return;
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}
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memcpy(&addr.s6_addr, rdata, sizeof(addr.s6_addr));
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if (!inet_ntop(AF_INET6, &addr.s6_addr, address, sizeof(address)))
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{
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DPRINTF(E_LOG, L_MDNS, "Could not print IPv6 address: %s\n", strerror(errno));
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return;
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}
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if (is_v6ll(&addr))
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{
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if (!if_indextoname(intf, ifname))
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{
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DPRINTF(E_LOG, L_MDNS, "Could not map interface index %d to a name\n", intf);
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return;
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}
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len = strlen(address);
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ret = snprintf(address + len, sizeof(address) - len, "%%%s", ifname);
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if ((ret < 0) || (ret > sizeof(address) - len))
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{
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DPRINTF(E_LOG, L_MDNS, "Buffer too short for scoped IPv6 LL\n");
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return;
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}
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}
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DPRINTF(E_DBG, L_MDNS, "Service %s, hostname %s resolved to %s\n", rb_data->name, hostname, address);
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/* Execute callback (mb->cb) with all the data */
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rb_data->mb->cb(rb_data->name, rb_data->mb->type, rb_data->domain, hostname, AF_INET6, address, rb_data->port, &rb_data->txt_kv);
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/* Got a suitable address, stop record browser */
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break;
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case AVAHI_BROWSER_REMOVE:
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/* Not handled - record browser lifetime too short for this to happen */
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return;
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case AVAHI_BROWSER_CACHE_EXHAUSTED:
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case AVAHI_BROWSER_ALL_FOR_NOW:
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DPRINTF(E_DBG, L_MDNS, "Avahi Record Browser (%s v6): no more results (%s)\n", hostname,
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(event == AVAHI_BROWSER_CACHE_EXHAUSTED) ? "CACHE_EXHAUSTED" : "ALL_FOR_NOW");
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break;
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case AVAHI_BROWSER_FAILURE:
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DPRINTF(E_LOG, L_MDNS, "Avahi Record Browser (%s v6) failure: %s\n", hostname,
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avahi_strerror(avahi_client_errno(avahi_record_browser_get_client(b))));
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break;
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}
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/* Cleanup when done/error */
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keyval_clear(&rb_data->txt_kv);
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free(rb_data->name);
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free(rb_data->domain);
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free(rb_data);
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avahi_record_browser_free(b);
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}
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static void
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@ -365,15 +520,13 @@ browse_resolve_callback(AvahiServiceResolver *r, AvahiIfIndex intf, AvahiProtoco
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const char *name, const char *type, const char *domain, const char *hostname, const AvahiAddress *addr,
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uint16_t port, AvahiStringList *txt, AvahiLookupResultFlags flags, void *userdata)
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{
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char address[AVAHI_ADDRESS_STR_MAX + IF_NAMESIZE + 2];
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char ifname[IF_NAMESIZE];
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struct keyval txt_kv;
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AvahiClient *c;
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AvahiRecordBrowser *rb;
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struct mdns_browser *mb;
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struct mdns_record_browser *rb_data;
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char *key;
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char *value;
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size_t len;
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int family;
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int ll;
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int ret;
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mb = (struct mdns_browser *)userdata;
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@ -388,65 +541,39 @@ browse_resolve_callback(AvahiServiceResolver *r, AvahiIfIndex intf, AvahiProtoco
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case AVAHI_RESOLVER_FOUND:
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DPRINTF(E_DBG, L_MDNS, "Avahi Resolver: resolved service '%s' type '%s' proto %d\n", name, type, proto);
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ll = is_link_local(addr);
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switch (proto)
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rb_data = (struct mdns_record_browser *)malloc(sizeof(struct mdns_record_browser));
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if (!rb_data)
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{
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case AVAHI_PROTO_INET:
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if (ll)
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{
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family = AF_UNSPEC;
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DPRINTF(E_LOG, L_MDNS, "Out of memory for record browser data\n");
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DPRINTF(E_DBG, L_MDNS, "Discarding IPv4 LL address\n");
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break;
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}
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family = AF_INET;
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avahi_address_snprint(address, sizeof(address), addr);
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break;
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case AVAHI_PROTO_INET6:
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avahi_address_snprint(address, sizeof(address), addr);
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if (ll)
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{
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DPRINTF(E_DBG, L_MDNS, "Appending interface name to IPv6 LL address\n");
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if (!if_indextoname(intf, ifname))
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{
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DPRINTF(E_LOG, L_MDNS, "Could not map interface index %d to a name\n", intf);
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family = AF_UNSPEC;
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break;
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}
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len = strlen(address);
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ret = snprintf(address + len, sizeof(address) - len, "%%%s", ifname);
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if ((ret < 0) || (ret > sizeof(address) - len))
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{
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DPRINTF(E_LOG, L_MDNS, "Buffer too short for scoped IPv6 LL\n");
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family = AF_UNSPEC;
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break;
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}
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DPRINTF(E_DBG, L_MDNS, "Scoped IPv6 LL: %s\n", address);
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}
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family = AF_INET6;
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break;
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default:
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DPRINTF(E_INFO, L_MDNS, "Avahi Resolver: unknown protocol %d\n", proto);
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family = AF_UNSPEC;
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break;
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break;
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}
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if (family == AF_UNSPEC)
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break;
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memset(rb_data, 0, sizeof(struct mdns_record_browser));
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memset(&txt_kv, 0, sizeof(struct keyval));
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rb_data->mb = mb;
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rb_data->port = port;
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rb_data->name = strdup(name);
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if (!rb_data->name)
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{
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DPRINTF(E_LOG, L_MDNS, "Out of memory for service name\n");
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keyval_clear(&rb_data->txt_kv);
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free(rb_data);
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break;
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}
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rb_data->domain = strdup(domain);
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if (!rb_data->domain)
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{
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DPRINTF(E_LOG, L_MDNS, "Out of memory for service domain\n");
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keyval_clear(&rb_data->txt_kv);
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free(rb_data->name);
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free(rb_data);
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break;
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}
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while (txt)
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{
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@ -467,26 +594,63 @@ browse_resolve_callback(AvahiServiceResolver *r, AvahiIfIndex intf, AvahiProtoco
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len -= strlen(key) + 1;
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}
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ret = keyval_add_size(&txt_kv, key, value, len);
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ret = keyval_add_size(&rb_data->txt_kv, key, value, len);
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if (ret < 0)
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{
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DPRINTF(E_LOG, L_MDNS, "Could not build TXT record keyval\n");
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goto out_clear_txt_kv;
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keyval_clear(&rb_data->txt_kv);
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free(rb_data->name);
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free(rb_data->domain);
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free(rb_data);
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break;
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}
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txt = avahi_string_list_get_next(txt);
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}
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/* Execute callback (mb->cb) with all the data */
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mb->cb(name, type, domain, hostname, family, address, port, &txt_kv);
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c = avahi_service_resolver_get_client(r);
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out_clear_txt_kv:
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keyval_clear(&txt_kv);
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switch (proto)
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{
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case AVAHI_PROTO_INET:
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rb = avahi_record_browser_new(c, intf, proto, hostname,
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AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_A, 0,
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browse_record_callback_v4, rb_data);
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if (!rb)
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DPRINTF(E_LOG, L_MDNS, "Could not create v4 record browser for host %s: %s\n",
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hostname, avahi_strerror(avahi_client_errno(c)));
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break;
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case AVAHI_PROTO_INET6:
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rb = avahi_record_browser_new(c, intf, proto, hostname,
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AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_AAAA, 0,
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browse_record_callback_v6, rb_data);
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if (!rb)
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DPRINTF(E_LOG, L_MDNS, "Could not create v4 record browser for host %s: %s\n",
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hostname, avahi_strerror(avahi_client_errno(c)));
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break;
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default:
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DPRINTF(E_INFO, L_MDNS, "Avahi Resolver: unknown protocol %d\n", proto);
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rb = NULL;
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break;
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}
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if (!rb)
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{
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keyval_clear(&rb_data->txt_kv);
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free(rb_data->name);
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free(rb_data->domain);
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free(rb_data);
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}
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break;
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}
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avahi_service_resolver_free(r);
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return;
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}
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static void
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@ -522,8 +686,6 @@ browse_callback(AvahiServiceBrowser *b, AvahiIfIndex intf, AvahiProtocol proto,
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if (!res)
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DPRINTF(E_LOG, L_MDNS, "Failed to create service resolver: %s\n",
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avahi_strerror(avahi_client_errno(mdns_client)));
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/* browse_resolve_callback will execute callback (mb->cb) with all the data */
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break;
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case AVAHI_BROWSER_REMOVE:
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