dnssd.c

/**
 *  Copyright (C) 2011-2012  Juho Vähä-Herttua
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 */

/* These defines allow us to compile on iOS */
#ifndef __has_feature
# define __has_feature(x) 0
#endif
#ifndef __has_extension
# define __has_extension __has_feature
#endif

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "dnssdint.h"
#include "dnssd.h"
#include "global.h"
#include "compat.h"
#include "utils.h"

#include <dns_sd.h>

#define MAX_DEVICEID 18
#define MAX_SERVNAME 256

#if defined(HAVE_LIBDL) && !defined(__APPLE__)
# define USE_LIBDL 1
#else
# define USE_LIBDL 0
#endif

#if defined(WIN32) || USE_LIBDL
# ifdef WIN32
#  include <stdint.h>
#  if !defined(EFI32) && !defined(EFI64)
#   define DNSSD_STDCALL __stdcall
#  else
#   define DNSSD_STDCALL
#  endif
# else
#  include <dlfcn.h>
#  define DNSSD_STDCALL
# endif

typedef struct _DNSServiceRef_t *DNSServiceRef;
typedef union _TXTRecordRef_t { char PrivateData[16]; char *ForceNaturalAlignment; } TXTRecordRef;

typedef uint32_t DNSServiceFlags;
typedef int32_t  DNSServiceErrorType;

typedef void (DNSSD_STDCALL *DNSServiceRegisterReply)
    (
    DNSServiceRef                       sdRef,
    DNSServiceFlags                     flags,
    DNSServiceErrorType                 errorCode,
    const char                          *name,
    const char                          *regtype,
    const char                          *domain,
    void                                *context
    );

#else
//# include <dns_sd.h>
# define DNSSD_STDCALL
#endif

typedef DNSServiceErrorType (DNSSD_STDCALL *DNSServiceRegister_t)
        (
                DNSServiceRef                       *sdRef,
                DNSServiceFlags                     flags,
                uint32_t                            interfaceIndex,
                const char                          *name,
                const char                          *regtype,
                const char                          *domain,
                const char                          *host,
                uint16_t                            port,
                uint16_t                            txtLen,
                const void                          *txtRecord,
                DNSServiceRegisterReply             callBack,
                void                                *context
        );
typedef void (DNSSD_STDCALL *DNSServiceRefDeallocate_t)(DNSServiceRef sdRef);
typedef void (DNSSD_STDCALL *TXTRecordCreate_t)
        (
                TXTRecordRef     *txtRecord,
                uint16_t         bufferLen,
                void             *buffer
        );
typedef void (DNSSD_STDCALL *TXTRecordDeallocate_t)(TXTRecordRef *txtRecord);
typedef DNSServiceErrorType (DNSSD_STDCALL *TXTRecordSetValue_t)
        (
                TXTRecordRef     *txtRecord,
                const char       *key,
                uint8_t          valueSize,
                const void       *value
        );
typedef uint16_t (DNSSD_STDCALL *TXTRecordGetLength_t)(const TXTRecordRef *txtRecord);
typedef const void * (DNSSD_STDCALL *TXTRecordGetBytesPtr_t)(const TXTRecordRef *txtRecord);


struct dnssd_s {
#ifdef WIN32
    HMODULE module;
#elif USE_LIBDL
    void *module;
#endif

    DNSServiceRegister_t       DNSServiceRegister;
    DNSServiceRefDeallocate_t  DNSServiceRefDeallocate;
    TXTRecordCreate_t          TXTRecordCreate;
    TXTRecordSetValue_t        TXTRecordSetValue;
    TXTRecordGetLength_t       TXTRecordGetLength;
    TXTRecordGetBytesPtr_t     TXTRecordGetBytesPtr;
    TXTRecordDeallocate_t      TXTRecordDeallocate;

    TXTRecordRef raop_record;
    TXTRecordRef airplay_record;

    DNSServiceRef raop_service;
    DNSServiceRef airplay_service;

    char *name;
    int name_len;

    char *hw_addr;
    int hw_addr_len;
};



dnssd_t *
dnssd_init(const char* name, int name_len, const char* hw_addr, int hw_addr_len, int *error)
{
    dnssd_t *dnssd;

    if (error) *error = DNSSD_ERROR_NOERROR;

    dnssd = calloc(1, sizeof(dnssd_t));
    if (!dnssd) {
        if (error) *error = DNSSD_ERROR_OUTOFMEM;
        return NULL;
    }

#ifdef WIN32
    dnssd->module = LoadLibraryA("dnssd.dll");
	if (!dnssd->module) {
		if (error) *error = DNSSD_ERROR_LIBNOTFOUND;
		free(dnssd);
		return NULL;
	}
	dnssd->DNSServiceRegister = (DNSServiceRegister_t)GetProcAddress(dnssd->module, "DNSServiceRegister");
	dnssd->DNSServiceRefDeallocate = (DNSServiceRefDeallocate_t)GetProcAddress(dnssd->module, "DNSServiceRefDeallocate");
	dnssd->TXTRecordCreate = (TXTRecordCreate_t)GetProcAddress(dnssd->module, "TXTRecordCreate");
	dnssd->TXTRecordSetValue = (TXTRecordSetValue_t)GetProcAddress(dnssd->module, "TXTRecordSetValue");
	dnssd->TXTRecordGetLength = (TXTRecordGetLength_t)GetProcAddress(dnssd->module, "TXTRecordGetLength");
	dnssd->TXTRecordGetBytesPtr = (TXTRecordGetBytesPtr_t)GetProcAddress(dnssd->module, "TXTRecordGetBytesPtr");
	dnssd->TXTRecordDeallocate = (TXTRecordDeallocate_t)GetProcAddress(dnssd->module, "TXTRecordDeallocate");

	if (!dnssd->DNSServiceRegister || !dnssd->DNSServiceRefDeallocate || !dnssd->TXTRecordCreate ||
	    !dnssd->TXTRecordSetValue || !dnssd->TXTRecordGetLength || !dnssd->TXTRecordGetBytesPtr ||
	    !dnssd->TXTRecordDeallocate) {
		if (error) *error = DNSSD_ERROR_PROCNOTFOUND;
		FreeLibrary(dnssd->module);
		free(dnssd);
		return NULL;
	}
#elif USE_LIBDL
    dnssd->module = dlopen("libdns_sd.so", RTLD_LAZY);
	if (!dnssd->module) {
		if (error) *error = DNSSD_ERROR_LIBNOTFOUND;
		free(dnssd);
		return NULL;
	}
	dnssd->DNSServiceRegister = (DNSServiceRegister_t)dlsym(dnssd->module, "DNSServiceRegister");
	dnssd->DNSServiceRefDeallocate = (DNSServiceRefDeallocate_t)dlsym(dnssd->module, "DNSServiceRefDeallocate");
	dnssd->TXTRecordCreate = (TXTRecordCreate_t)dlsym(dnssd->module, "TXTRecordCreate");
	dnssd->TXTRecordSetValue = (TXTRecordSetValue_t)dlsym(dnssd->module, "TXTRecordSetValue");
	dnssd->TXTRecordGetLength = (TXTRecordGetLength_t)dlsym(dnssd->module, "TXTRecordGetLength");
	dnssd->TXTRecordGetBytesPtr = (TXTRecordGetBytesPtr_t)dlsym(dnssd->module, "TXTRecordGetBytesPtr");
	dnssd->TXTRecordDeallocate = (TXTRecordDeallocate_t)dlsym(dnssd->module, "TXTRecordDeallocate");

	if (!dnssd->DNSServiceRegister || !dnssd->DNSServiceRefDeallocate || !dnssd->TXTRecordCreate ||
	    !dnssd->TXTRecordSetValue || !dnssd->TXTRecordGetLength || !dnssd->TXTRecordGetBytesPtr ||
	    !dnssd->TXTRecordDeallocate) {
		if (error) *error = DNSSD_ERROR_PROCNOTFOUND;
		dlclose(dnssd->module);
		free(dnssd);
		return NULL;
	}
#else
    dnssd->DNSServiceRegister = &DNSServiceRegister;
    dnssd->DNSServiceRefDeallocate = &DNSServiceRefDeallocate;
    dnssd->TXTRecordCreate = &TXTRecordCreate;
    dnssd->TXTRecordSetValue = &TXTRecordSetValue;
    dnssd->TXTRecordGetLength = &TXTRecordGetLength;
    dnssd->TXTRecordGetBytesPtr = &TXTRecordGetBytesPtr;
    dnssd->TXTRecordDeallocate = &TXTRecordDeallocate;
#endif

    dnssd->name_len = name_len;
    dnssd->name = calloc(1, name_len);
    if (!dnssd->name) {
        free(dnssd);
        if (error) *error = DNSSD_ERROR_OUTOFMEM;
        return NULL;
    }
    memcpy(dnssd->name, name, name_len);

    dnssd->hw_addr_len = hw_addr_len;
    dnssd->hw_addr = calloc(1, dnssd->hw_addr_len);
    if (!dnssd->hw_addr) {
        free(dnssd->name);
        free(dnssd);
        if (error) *error = DNSSD_ERROR_OUTOFMEM;
        return NULL;
    }

    memcpy(dnssd->hw_addr, hw_addr, hw_addr_len);

    return dnssd;
}

void
dnssd_destroy(dnssd_t *dnssd)
{
    if (dnssd) {
#ifdef WIN32
        FreeLibrary(dnssd->module);
#elif USE_LIBDL
        dlclose(dnssd->module);
#endif
        free(dnssd);
    }
}

int
dnssd_register_raop(dnssd_t *dnssd, unsigned short port)
{
    char servname[MAX_SERVNAME];

    assert(dnssd);

    dnssd->TXTRecordCreate(&dnssd->raop_record, 0, NULL);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "ch", strlen(RAOP_CH), RAOP_CH);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "cn", strlen(RAOP_CN), RAOP_CN);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "da", strlen(RAOP_DA), RAOP_DA);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "et", strlen(RAOP_ET), RAOP_ET);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "vv", strlen(RAOP_VV), RAOP_VV);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "ft", strlen(RAOP_FT), RAOP_FT);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "am", strlen(GLOBAL_MODEL), GLOBAL_MODEL);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "md", strlen(RAOP_MD), RAOP_MD);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "rhd", strlen(RAOP_RHD), RAOP_RHD);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "pw", strlen("false"), "false");
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "sr", strlen(RAOP_SR), RAOP_SR);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "ss", strlen(RAOP_SS), RAOP_SS);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "sv", strlen(RAOP_SV), RAOP_SV);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "tp", strlen(RAOP_TP), RAOP_TP);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "txtvers", strlen(RAOP_TXTVERS), RAOP_TXTVERS);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "sf", strlen(RAOP_SF), RAOP_SF);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "vs", strlen(RAOP_VS), RAOP_VS);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "vn", strlen(RAOP_VN), RAOP_VN);
    dnssd->TXTRecordSetValue(&dnssd->raop_record, "pk", strlen(RAOP_PK), RAOP_PK);

    /* Convert hardware address to string */
    if (utils_hwaddr_raop(servname, sizeof(servname), dnssd->hw_addr, dnssd->hw_addr_len) < 0) {
        /* FIXME: handle better */
        return -1;
    }

    /* Check that we have bytes for 'hw@name' format */
    if (sizeof(servname) < strlen(servname) + 1 + dnssd->name_len + 1) {
        /* FIXME: handle better */
        return -2;
    }

    strncat(servname, "@", sizeof(servname)-strlen(servname)-1);
    strncat(servname, dnssd->name, sizeof(servname)-strlen(servname)-1);

    /* Register the service */
    dnssd->DNSServiceRegister(&dnssd->raop_service, 0, 0,
                              servname, "_raop._tcp",
                              NULL, NULL,
                              htons(port),
                              dnssd->TXTRecordGetLength(&dnssd->raop_record),
                              dnssd->TXTRecordGetBytesPtr(&dnssd->raop_record),
                              NULL, NULL);


    return 1;
}

int
dnssd_register_airplay(dnssd_t *dnssd, unsigned short port)
{
    char device_id[3 * MAX_HWADDR_LEN];

    assert(dnssd);

    /* Convert hardware address to string */
    if (utils_hwaddr_airplay(device_id, sizeof(device_id), dnssd->hw_addr, dnssd->hw_addr_len) < 0) {
        /* FIXME: handle better */
        return -1;
    }


    dnssd->TXTRecordCreate(&dnssd->airplay_record, 0, NULL);
    dnssd->TXTRecordSetValue(&dnssd->airplay_record, "deviceid", strlen(device_id), device_id);
    dnssd->TXTRecordSetValue(&dnssd->airplay_record, "features", strlen(AIRPLAY_FEATURES), AIRPLAY_FEATURES);
    dnssd->TXTRecordSetValue(&dnssd->airplay_record, "flags", strlen(AIRPLAY_FLAGS), AIRPLAY_FLAGS);
    dnssd->TXTRecordSetValue(&dnssd->airplay_record, "model", strlen(GLOBAL_MODEL), GLOBAL_MODEL);
    dnssd->TXTRecordSetValue(&dnssd->airplay_record, "pk", strlen(AIRPLAY_PK), AIRPLAY_PK);
    dnssd->TXTRecordSetValue(&dnssd->airplay_record, "pi", strlen(AIRPLAY_PI), AIRPLAY_PI);
    dnssd->TXTRecordSetValue(&dnssd->airplay_record, "srcvers", strlen(AIRPLAY_SRCVERS), AIRPLAY_SRCVERS);
    dnssd->TXTRecordSetValue(&dnssd->airplay_record, "vv", strlen(AIRPLAY_VV), AIRPLAY_VV);

    /* Register the service */
    dnssd->DNSServiceRegister(&dnssd->airplay_service, 0, 0,
                              dnssd->name, "_airplay._tcp",
                              NULL, NULL,
                              htons(port),
                              dnssd->TXTRecordGetLength(&dnssd->airplay_record),
                              dnssd->TXTRecordGetBytesPtr(&dnssd->airplay_record),
                              NULL, NULL);

    return 1;
}

char * 
dnssd_get_airplay_txt(dnssd_t *dnssd, int *length)
{
    *length = dnssd->TXTRecordGetLength(&dnssd->airplay_record);
    return dnssd->TXTRecordGetBytesPtr(&dnssd->airplay_record);
}

char *
dnssd_get_name(dnssd_t *dnssd, int *length)
{
    *length = dnssd->name_len;
    return dnssd->name;
}

char *
dnssd_get_hw_addr(dnssd_t *dnssd, int *length)
{
    *length = dnssd->hw_addr_len;
    return dnssd->hw_addr;
}

void
dnssd_unregister_raop(dnssd_t *dnssd)
{
    assert(dnssd);

    if (!dnssd->raop_service) {
        return;
    }

    /* Deallocate TXT record */
    dnssd->TXTRecordDeallocate(&dnssd->raop_record);

    dnssd->DNSServiceRefDeallocate(dnssd->raop_service);
    dnssd->raop_service = NULL;

    if (dnssd->airplay_service == NULL) {
        free(dnssd->name);
        free(dnssd->hw_addr);
    }
}

void
dnssd_unregister_airplay(dnssd_t *dnssd)
{
    assert(dnssd);

    if (!dnssd->airplay_service) {
        return;
    }

    /* Deallocate TXT record */
    dnssd->TXTRecordDeallocate(&dnssd->airplay_record);

    dnssd->DNSServiceRefDeallocate(dnssd->airplay_service);
    dnssd->airplay_service = NULL;

    if (dnssd->raop_service == NULL) {
        free(dnssd->name);
        free(dnssd->hw_addr);
    }
}