X-Git-Url: https://git.netwichtig.de/gitweb/?a=blobdiff_plain;ds=sidebyside;f=src%2Fcoremods%2Fcore_dns.cpp;h=a7ed8d3ed3a63334193cac94cfab8e6d24dd5d96;hb=edfe7f035ea83731b9316d40d64402411a531426;hp=47d5b3cab2062afa9a10e4a8e612164b8ceb1f1a;hpb=f62654a6859998f9d63eb22702c572d5ebcff15c;p=user%2Fhenk%2Fcode%2Finspircd.git diff --git a/src/coremods/core_dns.cpp b/src/coremods/core_dns.cpp index 47d5b3cab..a7ed8d3ed 100644 --- a/src/coremods/core_dns.cpp +++ b/src/coremods/core_dns.cpp @@ -116,20 +116,20 @@ class Packet : public Query Question UnpackQuestion(const unsigned char* input, unsigned short input_size, unsigned short& pos) { - Question question; + Question q; - question.name = this->UnpackName(input, input_size, pos); + q.name = this->UnpackName(input, input_size, pos); if (pos + 4 > input_size) throw Exception("Unable to unpack question"); - question.type = static_cast(input[pos] << 8 | input[pos + 1]); + q.type = static_cast(input[pos] << 8 | input[pos + 1]); pos += 2; - question.qclass = input[pos] << 8 | input[pos + 1]; + // Skip over query class code pos += 2; - return question; + return q; } ResourceRecord UnpackResourceRecord(const unsigned char* input, unsigned short input_size, unsigned short& pos) @@ -201,7 +201,7 @@ class Packet : public Query static const int HEADER_LENGTH = 12; /* ID for this packet */ - unsigned short id; + RequestId id; /* Flags on the packet */ unsigned short flags; @@ -219,9 +219,6 @@ class Packet : public Query this->id = (input[packet_pos] << 8) | input[packet_pos + 1]; packet_pos += 2; - if (this->id >= MAX_REQUEST_ID) - throw Exception("Query ID too large?"); - this->flags = (input[packet_pos] << 8) | input[packet_pos + 1]; packet_pos += 2; @@ -239,8 +236,10 @@ class Packet : public Query ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "qdcount: " + ConvToStr(qdcount) + " ancount: " + ConvToStr(ancount) + " nscount: " + ConvToStr(nscount) + " arcount: " + ConvToStr(arcount)); - for (unsigned i = 0; i < qdcount; ++i) - this->questions.push_back(this->UnpackQuestion(input, len, packet_pos)); + if (qdcount != 1) + throw Exception("Question count != 1 in incoming packet"); + + this->question = this->UnpackQuestion(input, len, packet_pos); for (unsigned i = 0; i < ancount; ++i) this->answers.push_back(this->UnpackResourceRecord(input, len, packet_pos)); @@ -257,18 +256,17 @@ class Packet : public Query output[pos++] = this->id & 0xFF; output[pos++] = this->flags >> 8; output[pos++] = this->flags & 0xFF; - output[pos++] = this->questions.size() >> 8; - output[pos++] = this->questions.size() & 0xFF; - output[pos++] = this->answers.size() >> 8; - output[pos++] = this->answers.size() & 0xFF; + output[pos++] = 0; // Question count, high byte + output[pos++] = 1; // Question count, low byte + output[pos++] = 0; // Answer count, high byte + output[pos++] = 0; // Answer count, low byte output[pos++] = 0; output[pos++] = 0; output[pos++] = 0; output[pos++] = 0; - for (unsigned i = 0; i < this->questions.size(); ++i) { - Question& q = this->questions[i]; + Question& q = this->question; if (q.type == QUERY_PTR) { @@ -310,84 +308,9 @@ class Packet : public Query memcpy(&output[pos], &s, 2); pos += 2; - s = htons(q.qclass); - memcpy(&output[pos], &s, 2); - pos += 2; - } - - for (unsigned int i = 0; i < answers.size(); i++) - { - ResourceRecord& rr = answers[i]; - - this->PackName(output, output_size, pos, rr.name); - - if (pos + 8 >= output_size) - throw Exception("Unable to pack packet"); - - short s = htons(rr.type); - memcpy(&output[pos], &s, 2); - pos += 2; - - s = htons(rr.qclass); - memcpy(&output[pos], &s, 2); - pos += 2; - - long l = htonl(rr.ttl); - memcpy(&output[pos], &l, 4); - pos += 4; - - switch (rr.type) - { - case QUERY_A: - { - if (pos + 6 > output_size) - throw Exception("Unable to pack packet"); - - irc::sockets::sockaddrs a; - irc::sockets::aptosa(rr.rdata, 0, a); - - s = htons(4); - memcpy(&output[pos], &s, 2); - pos += 2; - - memcpy(&output[pos], &a.in4.sin_addr, 4); - pos += 4; - break; - } - case QUERY_AAAA: - { - if (pos + 18 > output_size) - throw Exception("Unable to pack packet"); - - irc::sockets::sockaddrs a; - irc::sockets::aptosa(rr.rdata, 0, a); - - s = htons(16); - memcpy(&output[pos], &s, 2); - pos += 2; - - memcpy(&output[pos], &a.in6.sin6_addr, 16); - pos += 16; - break; - } - case QUERY_CNAME: - case QUERY_PTR: - { - if (pos + 2 >= output_size) - throw Exception("Unable to pack packet"); - - unsigned short packet_pos_save = pos; - pos += 2; - - this->PackName(output, output_size, pos, rr.rdata); - - s = htons(pos - packet_pos_save - 2); - memcpy(&output[packet_pos_save], &s, 2); - break; - } - default: - break; - } + // Query class, always IN + output[pos++] = 0; + output[pos++] = 1; } return pos; @@ -438,22 +361,22 @@ class MyManager : public Manager, public Timer, public EventHandler { const ResourceRecord& rr = r.answers[0]; ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "cache: added cache for " + rr.name + " -> " + rr.rdata + " ttl: " + ConvToStr(rr.ttl)); - this->cache[r.questions[0]] = r; + this->cache[r.question] = r; } public: - DNS::Request* requests[MAX_REQUEST_ID]; + DNS::Request* requests[MAX_REQUEST_ID+1]; MyManager(Module* c) : Manager(c), Timer(3600, true) { - for (int i = 0; i < MAX_REQUEST_ID; ++i) + for (unsigned int i = 0; i <= MAX_REQUEST_ID; ++i) requests[i] = NULL; ServerInstance->Timers.AddTimer(this); } ~MyManager() { - for (int i = 0; i < MAX_REQUEST_ID; ++i) + for (unsigned int i = 0; i <= MAX_REQUEST_ID; ++i) { DNS::Request* request = requests[i]; if (!request) @@ -473,46 +396,48 @@ class MyManager : public Manager, public Timer, public EventHandler /* Create an id */ unsigned int tries = 0; + int id; do { - req->id = ServerInstance->GenRandomInt(DNS::MAX_REQUEST_ID); + id = ServerInstance->GenRandomInt(DNS::MAX_REQUEST_ID+1); 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 - req->id = 0; - for (int i = 1; i < DNS::MAX_REQUEST_ID; i++) + id = -1; + for (unsigned int i = 0; i <= DNS::MAX_REQUEST_ID; i++) { if (!this->requests[i]) { - req->id = i; + id = i; break; } } - if (req->id == 0) + if (id == -1) throw Exception("DNS: All ids are in use"); break; } } - while (!req->id || this->requests[req->id]); + while (this->requests[id]); + req->id = id; this->requests[req->id] = req; Packet p; p.flags = QUERYFLAGS_RD; p.id = req->id; - p.questions.push_back(*req); + p.question = *req; unsigned char buffer[524]; unsigned short len = p.Pack(buffer, sizeof(buffer)); - /* Note that calling Pack() above can actually change the contents of p.questions[0].name, if the query is a PTR, + /* Note that calling Pack() above can actually change the contents of p.question.name, if the query is a PTR, * to contain the value that would be in the DNS cache, which is why this is here. */ - if (req->use_cache && this->CheckCache(req, p.questions[0])) + if (req->use_cache && this->CheckCache(req, p.question)) { ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Using cached result"); delete req; @@ -555,14 +480,13 @@ class MyManager : public Manager, public Timer, public EventHandler } } - void HandleEvent(EventType et, int) + void OnEventHandlerError(int errcode) CXX11_OVERRIDE { - if (et == EVENT_ERROR) - { - ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "UDP socket got an error event"); - return; - } + ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "UDP socket got an error event"); + } + void OnEventHandlerRead() CXX11_OVERRIDE + { unsigned char buffer[524]; irc::sockets::sockaddrs from; socklen_t x = sizeof(from); @@ -572,6 +496,15 @@ class MyManager : public Manager, public Timer, public EventHandler if (length < Packet::HEADER_LENGTH) return; + if (myserver != from) + { + std::string server1 = from.str(); + std::string server2 = myserver.str(); + ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Got a result from the wrong server! Bad NAT or DNS forging attempt? '%s' != '%s'", + server1.c_str(), server2.c_str()); + return; + } + Packet recv_packet; try @@ -584,15 +517,6 @@ class MyManager : public Manager, public Timer, public EventHandler return; } - if (myserver != from) - { - std::string server1 = from.str(); - std::string server2 = myserver.str(); - ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Got a result from the wrong server! Bad NAT or DNS forging attempt? '%s' != '%s'", - server1.c_str(), server2.c_str()); - return; - } - DNS::Request* request = this->requests[recv_packet.id]; if (request == NULL) { @@ -641,7 +565,7 @@ class MyManager : public Manager, public Timer, public EventHandler recv_packet.error = error; request->OnError(&recv_packet); } - else if (recv_packet.questions.empty() || recv_packet.answers.empty()) + else if (recv_packet.answers.empty()) { ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "No resource records returned"); ServerInstance->stats.DnsBad++; @@ -806,7 +730,7 @@ class ModuleDNS : public Module void OnUnloadModule(Module* mod) { - for (int i = 0; i < MAX_REQUEST_ID; ++i) + for (unsigned int i = 0; i <= MAX_REQUEST_ID; ++i) { DNS::Request* req = this->manager.requests[i]; if (!req)