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llares.cpp 16.28 KiB
/**
* @file llares.cpp
* @author Bryan O'Sullivan
* @date 2007-08-15
* @brief Wrapper for asynchronous DNS lookups.
*
* $LicenseInfo:firstyear=2007&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* 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;
* version 2.1 of the License only.
*
* 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.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#include "linden_common.h"
#include "llares.h"
#include <ares_dns.h>
#include <ares_version.h>
#include "apr_portable.h"
#include "apr_network_io.h"
#include "apr_poll.h"
#include "llapr.h"
#include "llareslistener.h"
#if defined(LL_WINDOWS)
#pragma warning (disable : 4355) // 'this' used in initializer list: yes, intentionally
# define ns_c_in 1
# define NS_HFIXEDSZ 12 /* #/bytes of fixed data in header */
# define NS_QFIXEDSZ 4 /* #/bytes of fixed data in query */
# define NS_RRFIXEDSZ 10 /* #/bytes of fixed data in r record */
#else
# include <arpa/nameser.h>
#endif
LLAres::HostResponder::~HostResponder()
{
}
void LLAres::HostResponder::hostResult(const hostent *ent)
{
llinfos << "LLAres::HostResponder::hostResult not implemented" << llendl;
}
void LLAres::HostResponder::hostError(int code)
{
llinfos << "LLAres::HostResponder::hostError " << code << ": "
<< LLAres::strerror(code) << llendl;
}
LLAres::NameInfoResponder::~NameInfoResponder()
{
}
void LLAres::NameInfoResponder::nameInfoResult(const char *node,
const char *service)
{
llinfos << "LLAres::NameInfoResponder::nameInfoResult not implemented"
<< llendl;
}
void LLAres::NameInfoResponder::nameInfoError(int code)
{
llinfos << "LLAres::NameInfoResponder::nameInfoError " << code << ": "
<< LLAres::strerror(code) << llendl;
}
LLAres::QueryResponder::~QueryResponder()
{
}
void LLAres::QueryResponder::queryResult(const char *buf, size_t len)
{
llinfos << "LLAres::QueryResponder::queryResult not implemented"
<< llendl;
}
void LLAres::QueryResponder::queryError(int code)
{
llinfos << "LLAres::QueryResponder::queryError " << code << ": "
<< LLAres::strerror(code) << llendl;
}
LLAres::LLAres() :
chan_(NULL),
mInitSuccess(false),
mListener(new LLAresListener(this))
{
if (ares_library_init( ARES_LIB_INIT_ALL ) != ARES_SUCCESS ||
ares_init(&chan_) != ARES_SUCCESS)
{
llwarns << "Could not succesfully initialize ares!" << llendl;
return;
}
mInitSuccess = true;
}
LLAres::~LLAres()
{
ares_destroy(chan_);
ares_library_cleanup();
}
void LLAres::cancel()
{
ares_cancel(chan_);
}
static void host_callback_1_5(void *arg, int status, int timeouts,
struct hostent *ent)
{
LLPointer<LLAres::HostResponder> *resp =
(LLPointer<LLAres::HostResponder> *) arg;
if (status == ARES_SUCCESS)
{
(*resp)->hostResult(ent);
} else {
(*resp)->hostError(status);
}
delete resp;
}
#if ARES_VERSION_MAJOR == 1 && ARES_VERSION_MINOR == 4
static void host_callback(void *arg, int status, struct hostent *ent)
{
host_callback_1_5(arg, status, 0, ent);
}
#else
# define host_callback host_callback_1_5
#endif
void LLAres::getHostByName(const char *name, HostResponder *resp,
int family)
{
ares_gethostbyname(chan_, name, family, host_callback,
new LLPointer<LLAres::HostResponder>(resp));
}
void LLAres::getSrvRecords(const std::string &name, SrvResponder *resp)
{
search(name, RES_SRV, resp);
}
void LLAres::rewriteURI(const std::string &uri, UriRewriteResponder *resp)
{
llinfos << "Rewriting " << uri << llendl;
resp->mUri = LLURI(uri);
search("_" + resp->mUri.scheme() + "._tcp." + resp->mUri.hostName(),
RES_SRV, resp);
}
LLQueryResponder::LLQueryResponder()
: LLAres::QueryResponder(),
mResult(ARES_ENODATA),
mType(RES_INVALID)
{
}
int LLQueryResponder::parseRR(const char *buf, size_t len, const char *&pos,
LLPointer<LLDnsRecord> &r)
{
std::string rrname;
size_t enclen;
int ret;
// RR name.
ret = LLAres::expandName(pos, buf, len, rrname, enclen);
if (ret != ARES_SUCCESS)
{
return ret;
}
pos += enclen;
if (pos + NS_RRFIXEDSZ > buf + len)
{
return ARES_EBADRESP;
}
int rrtype = DNS_RR_TYPE(pos);
int rrclass = DNS_RR_CLASS(pos);
int rrttl = DNS_RR_TTL(pos);
int rrlen = DNS_RR_LEN(pos);
if (rrclass != ns_c_in)
{
return ARES_EBADRESP;
}
pos += NS_RRFIXEDSZ;
if (pos + rrlen > buf + len)
{
return ARES_EBADRESP;
}
switch (rrtype)
{
case RES_A:
r = new LLARecord(rrname, rrttl);
break;
case RES_NS:
r = new LLNsRecord(rrname, rrttl);
break;
case RES_CNAME:
r = new LLCnameRecord(rrname, rrttl);
break;
case RES_PTR:
r = new LLPtrRecord(rrname, rrttl);
break;
case RES_AAAA:
r = new LLAaaaRecord(rrname, rrttl);
break;
case RES_SRV:
r = new LLSrvRecord(rrname, rrttl);
break;
default:
llinfos << "LLQueryResponder::parseRR got unknown RR type " << rrtype
<< llendl;
return ARES_EBADRESP;
}
ret = r->parse(buf, len, pos, rrlen);
if (ret == ARES_SUCCESS)
{
pos += rrlen;
} else {
r = NULL;
}
return ret;
}
int LLQueryResponder::parseSection(const char *buf, size_t len,
size_t count, const char *&pos,
dns_rrs_t &rrs)
{
int ret = ARES_SUCCESS;
for (size_t i = 0; i < count; i++)
{
LLPointer<LLDnsRecord> r;
ret = parseRR(buf, len, pos, r);
if (ret != ARES_SUCCESS)
{
break;
}
rrs.push_back(r);
}
return ret;
}
void LLQueryResponder::queryResult(const char *buf, size_t len)
{
const char *pos = buf;
int qdcount = DNS_HEADER_QDCOUNT(pos);
int ancount = DNS_HEADER_ANCOUNT(pos);
int nscount = DNS_HEADER_NSCOUNT(pos);
int arcount = DNS_HEADER_ARCOUNT(pos);
int ret;
if (qdcount == 0 || ancount + nscount + arcount == 0)
{
ret = ARES_ENODATA;
goto bail;
}
pos += NS_HFIXEDSZ;
for (int i = 0; i < qdcount; i++)
{
std::string ignore;
size_t enclen;
ret = LLAres::expandName(pos, buf, len, i == 0 ? mQuery : ignore,
enclen);
if (ret != ARES_SUCCESS)
{
goto bail;
}
pos += enclen;
if (i == 0)
{
int t = DNS_QUESTION_TYPE(pos);
switch (t)
{
case RES_A:
case RES_NS:
case RES_CNAME:
case RES_PTR:
case RES_AAAA:
case RES_SRV:
mType = (LLResType) t;
break;
default:
llinfos << "Cannot grok query type " << t << llendl;
ret = ARES_EBADQUERY;
goto bail;
}
}
pos += NS_QFIXEDSZ;
if (pos > buf + len)
{
ret = ARES_EBADRESP;
goto bail;
}
}
ret = parseSection(buf, len, ancount, pos, mAnswers);
if (ret != ARES_SUCCESS)
{
goto bail;
}
ret = parseSection(buf, len, nscount, pos, mAuthorities);
if (ret != ARES_SUCCESS)
{
goto bail;
}
ret = parseSection(buf, len, arcount, pos, mAdditional);
bail:
mResult = ret;
if (mResult == ARES_SUCCESS)
{
querySuccess();
} else {
queryError(mResult);
}
}
void LLQueryResponder::querySuccess()
{
llinfos << "LLQueryResponder::queryResult not implemented" << llendl;
}
void LLAres::SrvResponder::querySuccess()
{
if (mType == RES_SRV)
{
srvResult(mAnswers);
} else {
srvError(ARES_EBADRESP);
}
}
void LLAres::SrvResponder::queryError(int code)
{
srvError(code);
}
void LLAres::SrvResponder::srvResult(const dns_rrs_t &ents)
{
llinfos << "LLAres::SrvResponder::srvResult not implemented" << llendl;
for (size_t i = 0; i < ents.size(); i++)
{
const LLSrvRecord *s = (const LLSrvRecord *) ents[i].get();
llinfos << "[" << i << "] " << s->host() << ":" << s->port()
<< " priority " << s->priority()
<< " weight " << s->weight()
<< llendl;
}
}
void LLAres::SrvResponder::srvError(int code)
{
llinfos << "LLAres::SrvResponder::srvError " << code << ": "
<< LLAres::strerror(code) << llendl;
}
static void nameinfo_callback_1_5(void *arg, int status, int timeouts,
char *node, char *service)
{
LLPointer<LLAres::NameInfoResponder> *resp =
(LLPointer<LLAres::NameInfoResponder> *) arg;
if (status == ARES_SUCCESS)
{
(*resp)->nameInfoResult(node, service);
} else {
(*resp)->nameInfoError(status);
}
delete resp;
}
#if ARES_VERSION_MAJOR == 1 && ARES_VERSION_MINOR == 4
static void nameinfo_callback(void *arg, int status, char *node, char *service)
{
nameinfo_callback_1_5(arg, status, 0, node, service);
}
#else
# define nameinfo_callback nameinfo_callback_1_5
#endif
void LLAres::getNameInfo(const struct sockaddr &sa, socklen_t salen, int flags,
NameInfoResponder *resp)
{
ares_getnameinfo(chan_, &sa, salen, flags, nameinfo_callback,
new LLPointer<NameInfoResponder>(resp));
}
static void search_callback_1_5(void *arg, int status, int timeouts,
unsigned char *abuf, int alen)
{
LLPointer<LLAres::QueryResponder> *resp =
(LLPointer<LLAres::QueryResponder> *) arg;
if (status == ARES_SUCCESS)
{
(*resp)->queryResult((const char *) abuf, alen);
} else {
(*resp)->queryError(status);
}
delete resp;
}
#if ARES_VERSION_MAJOR == 1 && ARES_VERSION_MINOR == 4
static void search_callback(void *arg, int status, unsigned char *abuf,
int alen)
{
search_callback_1_5(arg, status, 0, abuf, alen);
}
#else
# define search_callback search_callback_1_5
#endif
void LLAres::search(const std::string &query, LLResType type,
QueryResponder *resp)
{
ares_search(chan_, query.c_str(), ns_c_in, type, search_callback,
new LLPointer<QueryResponder>(resp));
}
bool LLAres::process(U64 timeout)
{
if (!gAPRPoolp)
{
ll_init_apr();
}
ares_socket_t socks[ARES_GETSOCK_MAXNUM];
apr_pollfd_t aprFds[ARES_GETSOCK_MAXNUM];
apr_int32_t nsds = 0;
int nactive = 0;
int bitmask;
bitmask = ares_getsock(chan_, socks, ARES_GETSOCK_MAXNUM);
if (bitmask == 0)
{
return nsds > 0;
}
apr_status_t status;
LLAPRPool pool;
status = pool.getStatus() ;
ll_apr_assert_status(status);
for (int i = 0; i < ARES_GETSOCK_MAXNUM; i++)
{
if (ARES_GETSOCK_READABLE(bitmask, i))
{
aprFds[nactive].reqevents = APR_POLLIN | APR_POLLERR;
}
else if (ARES_GETSOCK_WRITABLE(bitmask, i))
{
aprFds[nactive].reqevents = APR_POLLOUT | APR_POLLERR;
} else {
continue;
}
apr_socket_t *aprSock = NULL;
status = apr_os_sock_put(&aprSock, (apr_os_sock_t *) &socks[i], pool.getAPRPool());
if (status != APR_SUCCESS)
{
ll_apr_warn_status(status);
return nsds > 0;
}
aprFds[nactive].desc.s = aprSock;
aprFds[nactive].desc_type = APR_POLL_SOCKET;
aprFds[nactive].p = pool.getAPRPool();
aprFds[nactive].rtnevents = 0;
aprFds[nactive].client_data = &socks[i];
nactive++;
}
if (nactive > 0)
{
status = apr_poll(aprFds, nactive, &nsds, timeout);
if (status != APR_SUCCESS && status != APR_TIMEUP)
{
ll_apr_warn_status(status);
}
for (int i = 0; i < nactive; i++)
{
int evts = aprFds[i].rtnevents;
int ifd = (evts & (APR_POLLIN | APR_POLLERR))
? *((int *) aprFds[i].client_data) : ARES_SOCKET_BAD;
int ofd = (evts & (APR_POLLOUT | APR_POLLERR))
? *((int *) aprFds[i].client_data) : ARES_SOCKET_BAD;
ares_process_fd(chan_, ifd, ofd);
}
}
return nsds > 0;
}
bool LLAres::processAll()
{
bool anyProcessed = false, ret;
do {
timeval tv;
ret = ares_timeout(chan_, NULL, &tv) != NULL;
if (ret)
{
ret = process(tv.tv_sec * 1000000LL + tv.tv_usec);
anyProcessed |= ret;
}
} while (ret);
return anyProcessed;
}
int LLAres::expandName(const char *encoded, const char *abuf, size_t alen,
std::string &s, size_t &enclen)
{
char *t;
int ret;
long e;
ret = ares_expand_name((const unsigned char *) encoded,
(const unsigned char *) abuf, alen, &t, &e);
if (ret == ARES_SUCCESS)
{
s.assign(t);
enclen = e;
ares_free_string(t);
}
return ret;
}
const char *LLAres::strerror(int code)
{
return ares_strerror(code);
}
LLAres *gAres;
LLAres *ll_init_ares()
{
if (gAres == NULL)
{
gAres = new LLAres();
}
return gAres;
}
LLDnsRecord::LLDnsRecord(LLResType type, const std::string &name,
unsigned ttl)
: LLRefCount(),
mType(type),
mName(name),
mTTL(ttl)
{
}
LLHostRecord::LLHostRecord(LLResType type, const std::string &name,
unsigned ttl)
: LLDnsRecord(type, name, ttl)
{
}
int LLHostRecord::parse(const char *buf, size_t len, const char *pos,
size_t rrlen)
{
int ret;
ret = LLAres::expandName(pos, buf, len, mHost);
if (ret != ARES_SUCCESS)
{
goto bail;
}
ret = ARES_SUCCESS;
bail:
return ret;
}
LLCnameRecord::LLCnameRecord(const std::string &name, unsigned ttl)
: LLHostRecord(RES_CNAME, name, ttl)
{
}
LLPtrRecord::LLPtrRecord(const std::string &name, unsigned ttl)
: LLHostRecord(RES_PTR, name, ttl)
{
}
LLAddrRecord::LLAddrRecord(LLResType type, const std::string &name,
unsigned ttl)
: LLDnsRecord(type, name, ttl),
mSize(0)
{
}
LLARecord::LLARecord(const std::string &name, unsigned ttl)
: LLAddrRecord(RES_A, name, ttl)
{
}
int LLARecord::parse(const char *buf, size_t len, const char *pos,
size_t rrlen)
{
int ret;
if (rrlen != sizeof(mSA.sin.sin_addr.s_addr))
{
ret = ARES_EBADRESP;
goto bail;
}
memset(&mSA, 0, sizeof(mSA));
memcpy(&mSA.sin.sin_addr.s_addr, pos, rrlen);
mSA.sin.sin_family = AF_INET6;
mSize = sizeof(mSA.sin);
ret = ARES_SUCCESS;
bail:
return ret;
}
LLAaaaRecord::LLAaaaRecord(const std::string &name, unsigned ttl)
: LLAddrRecord(RES_AAAA, name, ttl)
{
}
int LLAaaaRecord::parse(const char *buf, size_t len, const char *pos,
size_t rrlen)
{
int ret;
if (rrlen != sizeof(mSA.sin6.sin6_addr))
{
ret = ARES_EBADRESP;
goto bail;
}
memset(&mSA, 0, sizeof(mSA));
memcpy(&mSA.sin6.sin6_addr.s6_addr, pos, rrlen);
mSA.sin6.sin6_family = AF_INET6;
mSize = sizeof(mSA.sin6);
ret = ARES_SUCCESS;
bail:
return ret;
}
LLSrvRecord::LLSrvRecord(const std::string &name, unsigned ttl)
: LLHostRecord(RES_SRV, name, ttl),
mPriority(0),
mWeight(0),
mPort(0)
{
}
int LLSrvRecord::parse(const char *buf, size_t len, const char *pos,
size_t rrlen)
{
int ret;
if (rrlen < 6)
{
ret = ARES_EBADRESP;
goto bail;
}
memcpy(&mPriority, pos, 2);
memcpy(&mWeight, pos + 2, 2);
memcpy(&mPort, pos + 4, 2);
mPriority = ntohs(mPriority);
mWeight = ntohs(mWeight);
mPort = ntohs(mPort);
ret = LLHostRecord::parse(buf, len, pos + 6, rrlen - 6);
bail:
return ret;
}
LLNsRecord::LLNsRecord(const std::string &name, unsigned ttl)
: LLHostRecord(RES_NS, name, ttl)
{
}
void LLAres::UriRewriteResponder::queryError(int code)
{
std::vector<std::string> uris;
uris.push_back(mUri.asString());
rewriteResult(uris);
}
void LLAres::UriRewriteResponder::querySuccess()
{
std::vector<std::string> uris;
if (mType != RES_SRV)
{
goto bail;
}
for (size_t i = 0; i < mAnswers.size(); i++)
{
const LLSrvRecord *r = (const LLSrvRecord *) mAnswers[i].get();
if (r->type() == RES_SRV)
{
// Check the domain in the response to ensure that it's
// the same as the domain in the request, so that bad guys
// can't forge responses that point to their own login
// servers with their own certificates.
// Hard-coding the domain to check here is a bit of a
// hack. Hoist it to an outer caller if anyone ever needs
// this functionality on other domains.
static const std::string domain(".lindenlab.com");
const std::string &host = r->host();
std::string::size_type s = host.find(domain) + domain.length();
if (s != host.length() && s != host.length() - 1)
{
continue;
}
LLURI uri(mUri.scheme(),
mUri.userName(),
mUri.password(),
r->host(),
mUri.defaultPort() ? r->port() : mUri.hostPort(),
mUri.escapedPath(),
mUri.escapedQuery());
uris.push_back(uri.asString());
}
}
if (!uris.empty())
{
goto done;
}
bail:
uris.push_back(mUri.asString());
done:
rewriteResult(uris);
}
void LLAres::UriRewriteResponder::rewriteResult(
const std::vector<std::string> &uris)
{
llinfos << "LLAres::UriRewriteResponder::rewriteResult not implemented"
<< llendl;
for (size_t i = 0; i < uris.size(); i++)
{
llinfos << "[" << i << "] " << uris[i] << llendl;
}
}