Limit DNS cache size

[user/henk/code/inspircd.git] / src / dns.cpp

diff --git a/src/dns.cpp b/src/dns.cpp
index bede73a6fada8736bc5fa94f01de32cf27789e8a..3d3bc947fee2cfbee4f045e04b56b5eeb0730687 100644 (file)
--- a/src/dns.cpp
+++ b/src/dns.cpp
@@ -121,7 +121,7 @@ class CacheTimer : public Timer
        DNS* dns;
  public:
        CacheTimer(DNS* thisdns)
-               : Timer(3600, ServerInstance->Time(), true), dns(thisdns) { }
+               : Timer(5*60, ServerInstance->Time(), true), dns(thisdns) { }
 
        virtual void Tick(time_t)
        {
@@ -160,8 +160,10 @@ class RequestTimeout : public Timer
        }
 };
 
-CachedQuery::CachedQuery(const std::string &res, unsigned int ttl) : data(res)
+CachedQuery::CachedQuery(const std::string &res, QueryType qt, unsigned int ttl) : data(res), type(qt)
 {
+       if (ttl > 5*60)
+               ttl = 5*60;
        expires = ServerInstance->Time() + ttl;
 }
 
@@ -258,8 +260,28 @@ DNSRequest* DNS::AddQuery(DNSHeader *header, int &id, const char* original)
                return NULL;
 
        /* Create an id */
+       unsigned int tries = 0;
        do {
                id = ServerInstance->GenRandomInt(DNS::MAX_REQUEST_ID);
+               if (++tries == DNS::MAX_REQUEST_ID*5)
+               {
+                       // If we couldn't find an empty slot this many times, do a sequential scan as a last
+                       // resort. If an empty slot is found that way, go on, otherwise throw an exception
+                       id = -1;
+                       for (int i = 0; i < DNS::MAX_REQUEST_ID; i++)
+                       {
+                               if (!requests[i])
+                               {
+                                       id = i;
+                                       break;
+                               }
+                       }
+
+                       if (id == -1)
+                               throw ModuleException("DNS: All ids are in use");
+
+                       break;
+               }
        } while (requests[id]);
 
        DNSRequest* req = new DNSRequest(this, id, original);
@@ -657,19 +679,13 @@ DNSResult DNS::GetResult()
 
                        case DNS_QUERY_AAAA:
                        {
-                               inet_ntop(AF_INET6, data.first, formatted, sizeof(formatted));
-                               char* c = strstr(formatted,":0:");
-                               if (c != NULL)
+                               if (!inet_ntop(AF_INET6, data.first, formatted, sizeof(formatted)))
                                {
-                                       memmove(c+1,c+2,strlen(c+2) + 1);
-                                       c += 2;
-                                       while (memcmp(c,"0:",2) == 0)
-                                               memmove(c,c+2,strlen(c+2) + 1);
-                                       if (memcmp(c,"0",2) == 0)
-                                               *c = 0;
-                                       if (memcmp(formatted,"0::",3) == 0)
-                                               memmove(formatted,formatted + 1, strlen(formatted + 1) + 1);
+                                       std::string ro = req->orig;
+                                       delete req;
+                                       return DNSResult(this_id | ERROR_MASK, "inet_ntop() failed", 0, ro);
                                }
+
                                resultstr = formatted;
 
                                /* Special case. Sending ::1 around between servers
@@ -686,8 +702,16 @@ DNSResult DNS::GetResult()
                                /* Identical handling to PTR */
 
                        case DNS_QUERY_PTR:
+                       {
                                /* Reverse lookups just come back as char* */
                                resultstr = std::string((const char*)data.first);
+                               if (resultstr.find_first_not_of("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-") != std::string::npos)
+                               {
+                                       std::string ro = req->orig;
+                                       delete req;
+                                       return DNSResult(this_id | ERROR_MASK, "Invalid char(s) in reply", 0, ro);
+                               }
+                       }
                        break;
 
                        default:
@@ -696,8 +720,9 @@ DNSResult DNS::GetResult()
 
                /* Build the reply with the id and hostname/ip in it */
                std::string ro = req->orig;
+               DNSResult result = DNSResult(this_id,resultstr,ttl,ro,req->type);
                delete req;
-               return DNSResult(this_id,resultstr,ttl,ro);
+               return result;
        }
 }
 
@@ -925,11 +950,12 @@ Resolver::Resolver(const std::string &source, QueryType qt, bool &cached, Module
                {
                        ServerInstance->Res->DelCache(source);
                }
-               else
+               else if (CQ->type == qt)
                {
                        cached = true;
                        return;
                }
+               CQ = NULL;
        }
 
        switch (querytype)
@@ -1034,7 +1060,11 @@ void DNS::HandleEvent(EventType, int)
                                        ServerInstance->stats->statsDnsGood++;
 
                                if (!this->GetCache(res.original.c_str()))
-                                       this->cache->insert(std::make_pair(res.original.c_str(), CachedQuery(res.result, res.ttl)));
+                               {
+                                       if (cache->size() >= MAX_CACHE_SIZE)
+                                               cache->clear();
+                                       this->cache->insert(std::make_pair(res.original.c_str(), CachedQuery(res.result, res.type, res.ttl)));
+                               }
 
                                Classes[res.id]->OnLookupComplete(res.result, res.ttl, false);
                                delete Classes[res.id];