Add a new mDNS backend based on tinysvcmdns

This backend allows shairport to run without having a heavy daemon such
as avahi or mDNSResponder running in the background.
ipv6 support is more or less experimental right now.

1 files changed, 138 insertions, 0 deletions

diff --git a/mdns_tinysvcmdns.c b/mdns_tinysvcmdns.c
new file mode 100644
index 0000000..e92bbb7
--- /dev/null
+++ b/mdns_tinysvcmdns.c
@@ -0,0 +1,138 @@
+/*
+ * mDNS registration handler. This file is part of Shairport.
+ * Copyright (c) Paul Lietar 2013
+ * All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <net/if.h> 
+#include <ifaddrs.h>
+#include <unistd.h>
+#include "common.h"
+#include "mdns.h"
+
+#include "tinysvcmdns.h"
+
+static struct mdnsd *svr = NULL;
+
+static int mdns_tinysvcmdns_register(char *apname, int port) {
+    struct ifaddrs *ifalist;
+    struct ifaddrs *ifa;
+
+    svr = mdnsd_start();
+    if (svr == NULL) {
+        warn("tinysvcmdns: mdnsd_start() failed");
+        return -1;
+    }
+
+    char hostname[100];
+    gethostname(hostname, 100);
+
+    if (getifaddrs(&ifalist) < 0)
+    {
+        warn("tinysvcmdns: getifaddrs() failed");
+        return -1;
+    }
+
+    ifa = ifalist;
+
+    // Look for an ipv4/ipv6 non-loopback interface to use as the main one.
+    for (ifa = ifalist; ifa != NULL; ifa = ifa->ifa_next)
+    {
+        if (!(ifa->ifa_flags & IFF_LOOPBACK) && ifa->ifa_addr->sa_family == AF_INET)
+        {
+            uint32_t main_ip = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr.s_addr;
+
+            mdnsd_set_hostname(svr, hostname, main_ip);
+            break;
+        }
+        else if (!(ifa->ifa_flags & IFF_LOOPBACK) && ifa->ifa_addr->sa_family == AF_INET6)
+        {
+            struct in6_addr *addr = &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
+
+            mdnsd_set_hostname_v6(svr, hostname, addr);
+            break;
+        }
+    }
+
+    if (ifa == NULL)
+    {
+        warn("tinysvcmdns: no non-loopback ipv4 or ipv6 interface found");
+        return -1;
+    }
+
+
+    // Skip the first one, it was already added by set_hostname
+    for (ifa = ifa->ifa_next; ifa != NULL; ifa = ifa->ifa_next)
+    {
+        if (ifa->ifa_flags & IFF_LOOPBACK) // Skip loop-back interfaces
+            continue;
+
+        switch (ifa->ifa_addr->sa_family)
+        {
+            case AF_INET: { // ipv4
+                    uint32_t ip = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr.s_addr;
+                    struct rr_entry *a_e = rr_create_a(create_nlabel(hostname), ip);
+                    mdnsd_add_rr(svr, a_e);
+                }
+                break;
+            case AF_INET6: { // ipv6
+                    struct in6_addr *addr = &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
+                    struct rr_entry *aaaa_e = rr_create_aaaa(create_nlabel(hostname), addr);
+                    mdnsd_add_rr(svr, aaaa_e);
+                }
+                break;
+        }
+    }
+
+    freeifaddrs(ifa);
+
+    const char *txt[] = { MDNS_RECORD, NULL };
+    struct mdns_service *svc = mdnsd_register_svc(svr,
+                                apname,
+                                "_raop._tcp.local",
+                                port,
+                                NULL,
+                                txt);
+
+    mdns_service_destroy(svc);
+
+    return 0;
+}
+
+static void mdns_tinysvcmdns_unregister(void) {
+    if (svr)
+    {
+        mdnsd_stop(svr);
+        svr = NULL;
+    }
+}
+
+mdns_backend mdns_tinysvcmdns = {
+    .name = "tinysvcmdns",
+    .mdns_register = mdns_tinysvcmdns_register,
+    .mdns_unregister = mdns_tinysvcmdns_unregister
+};
+