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#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include "global/debug.h"
#include "rgw_resolve.h"
#define dout_subsys ceph_subsys_rgw
class RGWDNSResolver {
list<res_state> states;
Mutex lock;
int get_state(res_state *ps);
void put_state(res_state s);
public:
~RGWDNSResolver();
RGWDNSResolver() : lock("RGWDNSResolver") {}
int resolve_cname(const string& hostname, string& cname, bool *found);
};
RGWDNSResolver::~RGWDNSResolver()
{
list<res_state>::iterator iter;
for (iter = states.begin(); iter != states.end(); ++iter) {
struct __res_state *s = *iter;
delete s;
}
}
int RGWDNSResolver::get_state(res_state *ps)
{
lock.Lock();
if (!states.empty()) {
res_state s = states.front();
states.pop_front();
lock.Unlock();
*ps = s;
return 0;
}
lock.Unlock();
struct __res_state *s = new struct __res_state;
s->options = 0;
if (res_ninit(s) < 0) {
delete s;
dout(0) << "ERROR: failed to call res_ninit()" << dendl;
return -EINVAL;
}
*ps = s;
return 0;
}
void RGWDNSResolver::put_state(res_state s)
{
Mutex::Locker l(lock);
states.push_back(s);
}
int RGWDNSResolver::resolve_cname(const string& hostname, string& cname, bool *found)
{
res_state res;
*found = false;
int r = get_state(&res);
if (r < 0) {
return r;
}
int ret;
#define LARGE_ENOUGH_DNS_BUFSIZE 1024
unsigned char buf[LARGE_ENOUGH_DNS_BUFSIZE];
#define MAX_FQDN_SIZE 255
char host[MAX_FQDN_SIZE + 1];
const char *origname = hostname.c_str();
unsigned char *pt, *answer;
unsigned char *answend;
int len = res_nquery(res, origname, C_IN, T_CNAME, buf, sizeof(buf));
if (len < 0) {
dout(20) << "res_query() failed" << dendl;
ret = 0;
goto done;
}
answer = buf;
pt = answer + sizeof(HEADER);
answend = answer + len;
/* read query */
if((len = dn_expand(answer, answend, pt, host, sizeof(host))) < 0) {
dout(0) << "ERROR: dn_expand() failed" << dendl;
ret = -EINVAL;
goto done;
}
pt += len;
if (pt + 4 > answend) {
dout(0) << "ERROR: bad reply" << dendl;
ret = -EIO;
goto done;
}
int type;
GETSHORT(type, pt);
if (type != T_CNAME) {
dout(0) << "ERROR: failed response type: type=%d (was expecting " << T_CNAME << ")" << dendl;
ret = -EIO;
goto done;
}
pt += INT16SZ; /* class */
/* read answer */
if((len = dn_expand(answer, answend, pt, host, sizeof(host))) < 0) {
ret = 0;
goto done;
}
pt += len;
dout(20) << "name=" << host << dendl;
if (pt + 10 > answend) {
dout(0) << "ERROR: bad reply" << dendl;
ret = -EIO;
goto done;
}
GETSHORT(type, pt);
pt += INT16SZ; /* class */
pt += INT32SZ; /* ttl */
pt += INT16SZ; /* size */
if((len = dn_expand(answer, answend, pt, host, sizeof(host))) < 0) {
ret = 0;
goto done;
}
dout(20) << "cname host=" << host << dendl;
cname = host;
*found = true;
ret = 0;
done:
put_state(res);
return ret;
}
RGWResolver::~RGWResolver() {
delete resolver;
}
RGWResolver::RGWResolver() {
resolver = new RGWDNSResolver;
}
int RGWResolver::resolve_cname(const string& hostname, string& cname, bool *found) {
return resolver->resolve_cname(hostname, cname, found);
};
RGWResolver *rgw_resolver;
void rgw_init_resolver()
{
rgw_resolver = new RGWResolver();
}
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