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Applying DNS TTL patch from #368.

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I've restructured/cleaned up the original patch by thomas.other a bit.
This commit is contained in:
Robin Sommer 2011-06-25 17:41:51 -07:00
parent ded395007f
commit 6b9d23abb2
3 changed files with 34 additions and 6 deletions
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35
src/DNS_Mgr.cc
View file

@ -63,6 +63,7 @@ public:
protected:
char* host; // if non-nil, this is a host request
uint32 addr;
uint32 ttl;
int request_pending;
};
@ -82,8 +83,8 @@ int DNS_Mgr_Request::MakeRequest(nb_dns_info* nb_dns)
class DNS_Mapping {
public:
DNS_Mapping(const char* host, struct hostent* h);
DNS_Mapping(uint32 addr, struct hostent* h);
DNS_Mapping(const char* host, struct hostent* h, uint32 ttl);
DNS_Mapping(uint32 addr, struct hostent* h, uint32 ttl);
DNS_Mapping(FILE* f);
int NoMapping() const { return no_mapping; }
@ -108,6 +109,9 @@ public:
int Failed() const { return failed; }
int Valid() const { return ! failed; }
bool Expired() const
{ return current_time() > (creation_time + req_ttl); }
protected:
friend class DNS_Mgr;
@ -119,6 +123,7 @@ protected:
char* req_host;
uint32 req_addr;
uint32 req_ttl;
int num_names;
char** names;
@ -146,21 +151,23 @@ static TableVal* empty_addr_set()
return new TableVal(s);
}
DNS_Mapping::DNS_Mapping(const char* host, struct hostent* h)
DNS_Mapping::DNS_Mapping(const char* host, struct hostent* h, uint32 ttl)
{
Init(h);
req_host = copy_string(host);
req_addr = 0;
req_ttl = ttl;
if ( names && ! names[0] )
names[0] = copy_string(host);
}
DNS_Mapping::DNS_Mapping(uint32 addr, struct hostent* h)
DNS_Mapping::DNS_Mapping(uint32 addr, struct hostent* h, uint32 ttl)
{
Init(h);
req_addr = addr;
req_host = 0;
req_ttl = ttl;
}
DNS_Mapping::DNS_Mapping(FILE* f)
@ -663,6 +670,7 @@ Val* DNS_Mgr::BuildMappingVal(DNS_Mapping* dm)
void DNS_Mgr::AddResult(DNS_Mgr_Request* dr, struct nb_dns_result* r)
{
struct hostent* h = (r && r->host_errno == 0) ? r->hostent : 0;
u_int32_t ttl = r->ttl;
DNS_Mapping* new_dm;
DNS_Mapping* prev_dm;
@ -670,7 +678,7 @@ void DNS_Mgr::AddResult(DNS_Mgr_Request* dr, struct nb_dns_result* r)
if ( dr->ReqHost() )
{
new_dm = new DNS_Mapping(dr->ReqHost(), h);
new_dm = new DNS_Mapping(dr->ReqHost(), h, ttl);
prev_dm = host_mappings.Insert(dr->ReqHost(), new_dm);
if ( new_dm->Failed() && prev_dm && prev_dm->Valid() )
@ -683,7 +691,7 @@ void DNS_Mgr::AddResult(DNS_Mgr_Request* dr, struct nb_dns_result* r)
}
else
{
new_dm = new DNS_Mapping(dr->ReqAddr(), h);
new_dm = new DNS_Mapping(dr->ReqAddr(), h, ttl);
uint32 tmp_addr = dr->ReqAddr();
HashKey k(&tmp_addr, 1);
prev_dm = addr_mappings.Insert(&k, new_dm);
@ -833,9 +841,16 @@ const char* DNS_Mgr::LookupAddrInCache(dns_mgr_addr_type addr)
{
HashKey h(&addr, 1);
DNS_Mapping* d = dns_mgr->addr_mappings.Lookup(&h);
if ( ! d )
return 0;
if ( d->Expired() )
{
dns_mgr->addr_mappings.Remove(&h);
return 0;
}
// The escapes in the following strings are to avoid having it
// interpreted as a trigraph sequence.
return d->names ? d->names[0] : "<\?\?\?>";
@ -844,9 +859,17 @@ const char* DNS_Mgr::LookupAddrInCache(dns_mgr_addr_type addr)
TableVal* DNS_Mgr::LookupNameInCache(string name)
{
DNS_Mapping* d = dns_mgr->host_mappings.Lookup(name.c_str());
if ( ! d || ! d->names )
return 0;
if ( d->Expired() )
{
HashKey h(name.c_str());
dns_mgr->host_mappings.Remove(&h);
return 0;
}
return d->AddrsSet();
}

4
src/nb_dns.c
View file

@ -438,6 +438,7 @@ nb_dns_activity(struct nb_dns_info *nd, struct nb_dns_result *nr, char *errstr)
register char **ap, **hap;
register u_int16_t id;
register const u_char *rdata;
register u_int32_t rttl;
register struct hostent *he;
register size_t rdlen;
ns_msg handle;
@ -557,6 +558,7 @@ nb_dns_activity(struct nb_dns_info *nd, struct nb_dns_result *nr, char *errstr)
rdata = ns_rr_rdata(rr);
rdlen = ns_rr_rdlen(rr);
rttl = ns_rr_ttl(rr);
switch (atype) {
case T_A:
@ -603,10 +605,12 @@ nb_dns_activity(struct nb_dns_info *nd, struct nb_dns_result *nr, char *errstr)
/* "Find first satisfactory answer" */
nr->hostent = he;
nr->ttl = rttl;
return (1);
}
}
nr->hostent = he;
nr->ttl = rttl;
return (1);
}

1
src/nb_dns.h
View file

@ -11,6 +11,7 @@ struct nb_dns_result {
void *cookie;
int host_errno;
struct hostent *hostent;
uint32_t ttl;
};
typedef unsigned int nb_uint32_t;