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-rw-r--r--modules/dns.cpp1135
1 files changed, 1135 insertions, 0 deletions
diff --git a/modules/dns.cpp b/modules/dns.cpp
new file mode 100644
index 000000000..d7eda6f9d
--- /dev/null
+++ b/modules/dns.cpp
@@ -0,0 +1,1135 @@
+/*
+ *
+ * (C) 2003-2024 Anope Team
+ * Contact us at team@anope.org
+ *
+ * Please read COPYING and README for further details.
+ *
+ * Based on the original code of Epona by Lara.
+ * Based on the original code of Services by Andy Church.
+ */
+
+#include "module.h"
+#include "modules/dns.h"
+
+using namespace DNS;
+
+namespace
+{
+ Anope::string admin, nameservers;
+ int refresh;
+ time_t timeout;
+}
+
+/** A full packet sent or received to/from the nameserver
+ */
+class Packet final
+ : public Query
+{
+ static bool IsValidName(const Anope::string &name)
+ {
+ return name.find_first_not_of("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-") == Anope::string::npos;
+ }
+
+ static void PackName(unsigned char *output, unsigned short output_size, unsigned short &pos, const Anope::string &name)
+ {
+ if (pos + name.length() + 2 > output_size)
+ throw SocketException("Unable to pack name");
+
+ Log(LOG_DEBUG_2) << "Resolver: PackName packing " << name;
+
+ sepstream sep(name, '.');
+ Anope::string token;
+
+ while (sep.GetToken(token))
+ {
+ output[pos++] = token.length();
+ memcpy(&output[pos], token.c_str(), token.length());
+ pos += token.length();
+ }
+
+ output[pos++] = 0;
+ }
+
+ static Anope::string UnpackName(const unsigned char *input, unsigned short input_size, unsigned short &pos)
+ {
+ Anope::string name;
+ unsigned short pos_ptr = pos, lowest_ptr = input_size;
+ bool compressed = false;
+
+ if (pos_ptr >= input_size)
+ throw SocketException("Unable to unpack name - no input");
+
+ while (input[pos_ptr] > 0)
+ {
+ unsigned short offset = input[pos_ptr];
+
+ if (offset & POINTER)
+ {
+ if ((offset & POINTER) != POINTER)
+ throw SocketException("Unable to unpack name - bogus compression header");
+ if (pos_ptr + 1 >= input_size)
+ throw SocketException("Unable to unpack name - bogus compression header");
+
+ /* Place pos at the second byte of the first (farthest) compression pointer */
+ if (!compressed)
+ {
+ ++pos;
+ compressed = true;
+ }
+
+ pos_ptr = (offset & LABEL) << 8 | input[pos_ptr + 1];
+
+ /* Pointers can only go back */
+ if (pos_ptr >= lowest_ptr)
+ throw SocketException("Unable to unpack name - bogus compression pointer");
+ lowest_ptr = pos_ptr;
+ }
+ else
+ {
+ if (pos_ptr + offset + 1 >= input_size)
+ throw SocketException("Unable to unpack name - offset too large");
+ if (!name.empty())
+ name += ".";
+ for (unsigned i = 1; i <= offset; ++i)
+ name += input[pos_ptr + i];
+
+ pos_ptr += offset + 1;
+ if (!compressed)
+ /* Move up pos */
+ pos = pos_ptr;
+ }
+ }
+
+ /* +1 pos either to one byte after the compression pointer or one byte after the ending \0 */
+ ++pos;
+
+ /* Empty names are valid (root domain) */
+
+ Log(LOG_DEBUG_2) << "Resolver: UnpackName successfully unpacked " << name;
+
+ return name;
+ }
+
+ Question UnpackQuestion(const unsigned char *input, unsigned short input_size, unsigned short &pos)
+ {
+ Question question;
+
+ question.name = this->UnpackName(input, input_size, pos);
+
+ if (pos + 4 > input_size)
+ throw SocketException("Unable to unpack question");
+
+ if (!IsValidName(question.name))
+ throw SocketException("Invalid question name");
+
+ question.type = static_cast<QueryType>(input[pos] << 8 | input[pos + 1]);
+ pos += 2;
+
+ question.qclass = input[pos] << 8 | input[pos + 1];
+ pos += 2;
+
+ return question;
+ }
+
+ ResourceRecord UnpackResourceRecord(const unsigned char *input, unsigned short input_size, unsigned short &pos)
+ {
+ ResourceRecord record = static_cast<ResourceRecord>(this->UnpackQuestion(input, input_size, pos));
+
+ if (pos + 6 > input_size)
+ throw SocketException("Unable to unpack resource record");
+
+ record.ttl = (input[pos] << 24) | (input[pos + 1] << 16) | (input[pos + 2] << 8) | input[pos + 3];
+ pos += 4;
+
+ //record.rdlength = input[pos] << 8 | input[pos + 1];
+ pos += 2;
+
+ switch (record.type)
+ {
+ case QUERY_A:
+ {
+ if (pos + 4 > input_size)
+ throw SocketException("Unable to unpack resource record");
+
+ in_addr a;
+ a.s_addr = input[pos] | (input[pos + 1] << 8) | (input[pos + 2] << 16) | (input[pos + 3] << 24);
+ pos += 4;
+
+ sockaddrs addrs;
+ addrs.ntop(AF_INET, &a);
+ if (!addrs.valid())
+ throw SocketException("Invalid IP");
+
+ record.rdata = addrs.addr();
+ break;
+ }
+ case QUERY_AAAA:
+ {
+ if (pos + 16 > input_size)
+ throw SocketException("Unable to unpack resource record");
+
+ in6_addr a;
+ for (int j = 0; j < 16; ++j)
+ a.s6_addr[j] = input[pos + j];
+ pos += 16;
+
+ sockaddrs addrs;
+ addrs.ntop(AF_INET6, &a);
+ if (!addrs.valid())
+ throw SocketException("Invalid IP");
+
+ record.rdata = addrs.addr();
+ break;
+ }
+ case QUERY_CNAME:
+ case QUERY_PTR:
+ {
+ record.rdata = this->UnpackName(input, input_size, pos);
+
+ if (!IsValidName(record.rdata))
+ throw SocketException("Invalid cname/ptr record data");
+
+ break;
+ }
+ default:
+ break;
+ }
+
+ Log(LOG_DEBUG_2) << "Resolver: " << record.name << " -> " << record.rdata;
+
+ return record;
+ }
+
+public:
+ static const int POINTER = 0xC0;
+ static const int LABEL = 0x3F;
+ static const int HEADER_LENGTH = 12;
+
+ Manager *manager;
+ /* Source or destination of the packet */
+ sockaddrs addr;
+ /* ID for this packet */
+ unsigned short id = 0;
+ /* Flags on the packet */
+ unsigned short flags = 0;
+
+ Packet(Manager *m, sockaddrs *a) : manager(m)
+ {
+ if (a)
+ addr = *a;
+ }
+
+ void Fill(const unsigned char *input, const unsigned short len)
+ {
+ if (len < HEADER_LENGTH)
+ throw SocketException("Unable to fill packet");
+
+ unsigned short packet_pos = 0;
+
+ this->id = (input[packet_pos] << 8) | input[packet_pos + 1];
+ packet_pos += 2;
+
+ this->flags = (input[packet_pos] << 8) | input[packet_pos + 1];
+ packet_pos += 2;
+
+ unsigned short qdcount = (input[packet_pos] << 8) | input[packet_pos + 1];
+ packet_pos += 2;
+
+ unsigned short ancount = (input[packet_pos] << 8) | input[packet_pos + 1];
+ packet_pos += 2;
+
+ unsigned short nscount = (input[packet_pos] << 8) | input[packet_pos + 1];
+ packet_pos += 2;
+
+ unsigned short arcount = (input[packet_pos] << 8) | input[packet_pos + 1];
+ packet_pos += 2;
+
+ Log(LOG_DEBUG_2) << "Resolver: qdcount: " << qdcount << " ancount: " << ancount << " nscount: " << nscount << " arcount: " << arcount;
+
+ for (unsigned i = 0; i < qdcount; ++i)
+ this->questions.push_back(this->UnpackQuestion(input, len, packet_pos));
+
+ for (unsigned i = 0; i < ancount; ++i)
+ this->answers.push_back(this->UnpackResourceRecord(input, len, packet_pos));
+
+ try
+ {
+ for (unsigned i = 0; i < nscount; ++i)
+ this->authorities.push_back(this->UnpackResourceRecord(input, len, packet_pos));
+
+ for (unsigned i = 0; i < arcount; ++i)
+ this->additional.push_back(this->UnpackResourceRecord(input, len, packet_pos));
+ }
+ catch (const SocketException &ex)
+ {
+ Log(LOG_DEBUG_2) << "Unable to parse ns/ar records: " << ex.GetReason();
+ }
+ }
+
+ unsigned short Pack(unsigned char *output, unsigned short output_size)
+ {
+ if (output_size < HEADER_LENGTH)
+ throw SocketException("Unable to pack packet");
+
+ unsigned short pos = 0;
+
+ output[pos++] = this->id >> 8;
+ 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++] = this->authorities.size() >> 8;
+ output[pos++] = this->authorities.size() & 0xFF;
+ output[pos++] = this->additional.size() >> 8;
+ output[pos++] = this->additional.size() & 0xFF;
+
+ for (auto &q : this->questions)
+ {
+ if (q.type == QUERY_PTR)
+ {
+ sockaddrs ip(q.name);
+ if (!ip.valid())
+ throw SocketException("Invalid IP");
+
+ switch (ip.family())
+ {
+ case AF_INET6:
+ q.name = ip.reverse() + ".ip6.arpa";
+ break;
+ case AF_INET:
+ q.name = ip.reverse() + ".in-addr.arpa";
+ break;
+ default:
+ throw SocketException("Unsupported IP Family");
+ }
+ }
+
+ this->PackName(output, output_size, pos, q.name);
+
+ if (pos + 4 >= output_size)
+ throw SocketException("Unable to pack packet");
+
+ short s = htons(q.type);
+ memcpy(&output[pos], &s, 2);
+ pos += 2;
+
+ s = htons(q.qclass);
+ memcpy(&output[pos], &s, 2);
+ pos += 2;
+ }
+
+ std::vector<ResourceRecord> types[] = { this->answers, this->authorities, this->additional };
+ for (auto &type : types)
+ {
+ for (const auto &rr : type)
+ {
+ this->PackName(output, output_size, pos, rr.name);
+
+ if (pos + 8 >= output_size)
+ throw SocketException("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 SocketException("Unable to pack packet");
+
+ sockaddrs a(rr.rdata);
+ if (!a.valid())
+ throw SocketException("Invalid IP");
+
+ s = htons(4);
+ memcpy(&output[pos], &s, 2);
+ pos += 2;
+
+ memcpy(&output[pos], &a.sa4.sin_addr, 4);
+ pos += 4;
+ break;
+ }
+ case QUERY_AAAA:
+ {
+ if (pos + 18 > output_size)
+ throw SocketException("Unable to pack packet");
+
+ sockaddrs a(rr.rdata);
+ if (!a.valid())
+ throw SocketException("Invalid IP");
+
+ s = htons(16);
+ memcpy(&output[pos], &s, 2);
+ pos += 2;
+
+ memcpy(&output[pos], &a.sa6.sin6_addr, 16);
+ pos += 16;
+ break;
+ }
+ case QUERY_NS:
+ case QUERY_CNAME:
+ case QUERY_PTR:
+ {
+ if (pos + 2 >= output_size)
+ throw SocketException("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;
+ }
+ case QUERY_SOA:
+ {
+ if (pos + 2 >= output_size)
+ throw SocketException("Unable to pack packet");
+
+ unsigned short packet_pos_save = pos;
+ pos += 2;
+
+ std::vector<Anope::string> ns;
+ spacesepstream(nameservers).GetTokens(ns);
+ this->PackName(output, output_size, pos, !ns.empty() ? ns[0] : "");
+ this->PackName(output, output_size, pos, admin.replace_all_cs('@', '.'));
+
+ if (pos + 20 >= output_size)
+ throw SocketException("Unable to pack SOA");
+
+ l = htonl(manager->GetSerial());
+ memcpy(&output[pos], &l, 4);
+ pos += 4;
+
+ l = htonl(refresh); // Refresh
+ memcpy(&output[pos], &l, 4);
+ pos += 4;
+
+ l = htonl(refresh); // Retry
+ memcpy(&output[pos], &l, 4);
+ pos += 4;
+
+ l = htonl(604800); // Expire
+ memcpy(&output[pos], &l, 4);
+ pos += 4;
+
+ l = htonl(0); // Minimum
+ memcpy(&output[pos], &l, 4);
+ pos += 4;
+
+ s = htons(pos - packet_pos_save - 2);
+ memcpy(&output[packet_pos_save], &s, 2);
+
+ break;
+ }
+ default:
+ break;
+ }
+ }
+ }
+
+ return pos;
+ }
+};
+
+namespace DNS
+{
+ class ReplySocket
+ : public virtual Socket
+ {
+ public:
+ ~ReplySocket() override = default;
+ virtual void Reply(Packet *p) = 0;
+ };
+}
+
+/* Listens for TCP requests */
+class TCPSocket final
+ : public ListenSocket
+{
+ Manager *manager;
+
+public:
+ /* A TCP client */
+ class Client final
+ : public ClientSocket
+ , public Timer
+ , public ReplySocket
+ {
+ Manager *manager;
+ Packet *packet = nullptr;
+ unsigned char packet_buffer[524];
+ int length = 0;
+
+ public:
+ Client(Manager *m, TCPSocket *l, int fd, const sockaddrs &addr)
+ : Socket(fd, l->GetFamily())
+ , ClientSocket(l, addr)
+ , Timer(5)
+ , manager(m)
+ {
+ Log(LOG_DEBUG_2) << "Resolver: New client from " << addr.addr();
+ }
+
+ ~Client() override
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Exiting client from " << clientaddr.addr();
+ delete packet;
+ }
+
+ /* Times out after a few seconds */
+ void Tick() override
+ {
+ }
+
+ void Reply(Packet *p) override
+ {
+ delete packet;
+ packet = p;
+ SocketEngine::Change(this, true, SF_WRITABLE);
+ }
+
+ bool ProcessRead() override
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Reading from DNS TCP socket";
+
+ int i = recv(this->GetFD(), reinterpret_cast<char *>(packet_buffer) + length, sizeof(packet_buffer) - length, 0);
+ if (i <= 0)
+ return false;
+
+ length += i;
+
+ unsigned short want_len = packet_buffer[0] << 8 | packet_buffer[1];
+ if (length >= want_len + 2)
+ {
+ int len = length - 2;
+ length -= want_len + 2;
+ return this->manager->HandlePacket(this, packet_buffer + 2, len, NULL);
+ }
+ return true;
+ }
+
+ bool ProcessWrite() override
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Writing to DNS TCP socket";
+
+ if (packet != NULL)
+ {
+ try
+ {
+ unsigned char buffer[65535];
+ unsigned short len = packet->Pack(buffer + 2, sizeof(buffer) - 2);
+
+ short s = htons(len);
+ memcpy(buffer, &s, 2);
+ len += 2;
+
+ send(this->GetFD(), reinterpret_cast<char *>(buffer), len, 0);
+ }
+ catch (const SocketException &) { }
+
+ delete packet;
+ packet = NULL;
+ }
+
+ SocketEngine::Change(this, false, SF_WRITABLE);
+ return true; /* Do not return false here, bind is unhappy we close the connection so soon after sending */
+ }
+ };
+
+ TCPSocket(Manager *m, const Anope::string &ip, int port) : Socket(-1, ip.find(':') == Anope::string::npos ? AF_INET : AF_INET6), ListenSocket(ip, port, ip.find(':') != Anope::string::npos), manager(m) { }
+
+ ClientSocket *OnAccept(int fd, const sockaddrs &addr) override
+ {
+ return new Client(this->manager, this, fd, addr);
+ }
+};
+
+/* Listens for UDP requests */
+class UDPSocket final
+ : public ReplySocket
+{
+ Manager *manager;
+ std::deque<Packet *> packets;
+
+public:
+ UDPSocket(Manager *m, const Anope::string &ip, int port) : Socket(-1, ip.find(':') == Anope::string::npos ? AF_INET : AF_INET6, SOCK_DGRAM), manager(m) { }
+
+ ~UDPSocket() override
+ {
+ for (const auto *packet : packets)
+ delete packet;
+ }
+
+ void Reply(Packet *p) override
+ {
+ packets.push_back(p);
+ SocketEngine::Change(this, true, SF_WRITABLE);
+ }
+
+ std::deque<Packet *>& GetPackets() { return packets; }
+
+ bool ProcessRead() override
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Reading from DNS UDP socket";
+
+ unsigned char packet_buffer[524];
+ sockaddrs from_server;
+ socklen_t x = sizeof(from_server);
+ int length = recvfrom(this->GetFD(), reinterpret_cast<char *>(&packet_buffer), sizeof(packet_buffer), 0, &from_server.sa, &x);
+ return this->manager->HandlePacket(this, packet_buffer, length, &from_server);
+ }
+
+ bool ProcessWrite() override
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Writing to DNS UDP socket";
+
+ Packet *r = !packets.empty() ? packets.front() : NULL;
+ if (r != NULL)
+ {
+ try
+ {
+ unsigned char buffer[524];
+ unsigned short len = r->Pack(buffer, sizeof(buffer));
+
+ sendto(this->GetFD(), reinterpret_cast<char *>(buffer), len, 0, &r->addr.sa, r->addr.size());
+ }
+ catch (const SocketException &) { }
+
+ delete r;
+ packets.pop_front();
+ }
+
+ if (packets.empty())
+ SocketEngine::Change(this, false, SF_WRITABLE);
+
+ return true;
+ }
+};
+
+class NotifySocket final
+ : public Socket
+{
+ Packet *packet;
+public:
+ NotifySocket(int family, Packet *p) : Socket(-1, family, SOCK_DGRAM), packet(p)
+ {
+ SocketEngine::Change(this, false, SF_READABLE);
+ SocketEngine::Change(this, true, SF_WRITABLE);
+ }
+
+ bool ProcessWrite() override
+ {
+ if (!packet)
+ return false;
+
+ Log(LOG_DEBUG_2) << "Resolver: Notifying slave " << packet->addr.addr();
+
+ try
+ {
+ unsigned char buffer[524];
+ unsigned short len = packet->Pack(buffer, sizeof(buffer));
+
+ sendto(this->GetFD(), reinterpret_cast<char *>(buffer), len, 0, &packet->addr.sa, packet->addr.size());
+ }
+ catch (const SocketException &) { }
+
+ delete packet;
+ packet = NULL;
+
+ return false;
+ }
+};
+
+class MyManager final
+ : public Manager
+ , public Timer
+{
+ uint32_t serial;
+
+ typedef std::unordered_map<Question, Query, Question::hash> cache_map;
+ cache_map cache;
+
+ TCPSocket *tcpsock = nullptr;
+ UDPSocket *udpsock = nullptr;
+
+ bool listen = false;
+ sockaddrs addrs;
+
+ std::vector<std::pair<Anope::string, short> > notify;
+public:
+ std::map<unsigned short, Request *> requests;
+
+ MyManager(Module *creator)
+ : Manager(creator)
+ , Timer(300, true)
+ , serial(Anope::CurTime)
+ , cur_id(Anope::RandomNumber())
+ {
+ }
+
+ ~MyManager() override
+ {
+ delete udpsock;
+ delete tcpsock;
+
+ for (std::map<unsigned short, Request *>::iterator it = this->requests.begin(), it_end = this->requests.end(); it != it_end;)
+ {
+ Request *request = it->second;
+ ++it;
+
+ Query rr(*request);
+ rr.error = ERROR_UNKNOWN;
+ request->OnError(&rr);
+
+ delete request;
+ }
+ this->requests.clear();
+
+ this->cache.clear();
+ }
+
+ void SetIPPort(const Anope::string &nameserver, const Anope::string &ip, unsigned short port, std::vector<std::pair<Anope::string, short> > n)
+ {
+ delete udpsock;
+ delete tcpsock;
+
+ udpsock = NULL;
+ tcpsock = NULL;
+
+ try
+ {
+ this->addrs.pton(nameserver.find(':') != Anope::string::npos ? AF_INET6 : AF_INET, nameserver, 53);
+
+ udpsock = new UDPSocket(this, ip, port);
+
+ if (!ip.empty())
+ {
+ udpsock->Bind(ip, port);
+ tcpsock = new TCPSocket(this, ip, port);
+ listen = true;
+ }
+ }
+ catch (const SocketException &ex)
+ {
+ Log() << "Unable to bind dns to " << ip << ":" << port << ": " << ex.GetReason();
+ }
+
+ notify = n;
+ }
+
+private:
+ unsigned short cur_id;
+
+ unsigned short GetID()
+ {
+ if (this->udpsock->GetPackets().size() == 65535)
+ throw SocketException("DNS queue full");
+
+ do
+ cur_id = (cur_id + 1) & 0xFFFF;
+ while (!cur_id || this->requests.count(cur_id));
+
+ return cur_id;
+ }
+
+public:
+ void Process(Request *req) override
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Processing request to lookup " << req->name << ", of type " << req->type;
+
+ if (req->use_cache && this->CheckCache(req))
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Using cached result";
+ delete req;
+ return;
+ }
+
+ if (!this->udpsock)
+ throw SocketException("No dns socket");
+
+ req->id = GetID();
+ this->requests[req->id] = req;
+
+ req->SetSecs(timeout);
+
+ auto *p = new Packet(this, &this->addrs);
+ p->flags = QUERYFLAGS_RD;
+ p->id = req->id;
+ p->questions.push_back(*req);
+
+ this->udpsock->Reply(p);
+ }
+
+ void RemoveRequest(Request *req) override
+ {
+ this->requests.erase(req->id);
+ }
+
+ bool HandlePacket(ReplySocket *s, const unsigned char *const packet_buffer, int length, sockaddrs *from) override
+ {
+ if (length < Packet::HEADER_LENGTH)
+ return true;
+
+ Packet recv_packet(this, from);
+
+ try
+ {
+ recv_packet.Fill(packet_buffer, length);
+ }
+ catch (const SocketException &ex)
+ {
+ Log(LOG_DEBUG_2) << ex.GetReason();
+ return true;
+ }
+
+ if (!(recv_packet.flags & QUERYFLAGS_QR))
+ {
+ if (!listen)
+ return true;
+ else if (recv_packet.questions.empty())
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Received a question with no questions?";
+ return true;
+ }
+
+ auto *packet = new Packet(recv_packet);
+ packet->flags |= QUERYFLAGS_QR; /* This is a response */
+ packet->flags |= QUERYFLAGS_AA; /* And we are authoritative */
+
+ packet->answers.clear();
+ packet->authorities.clear();
+ packet->additional.clear();
+
+ for (auto &q : recv_packet.questions)
+ {
+ if (q.type == QUERY_AXFR || q.type == QUERY_SOA)
+ {
+ ResourceRecord rr(q.name, QUERY_SOA);
+ packet->answers.push_back(rr);
+
+ if (q.type == QUERY_AXFR)
+ {
+ Anope::string token;
+ spacesepstream sep(nameservers);
+ while (sep.GetToken(token))
+ {
+ ResourceRecord rr2(q.name, QUERY_NS);
+ rr2.rdata = token;
+ packet->answers.push_back(rr2);
+ }
+ }
+ break;
+ }
+ }
+
+ FOREACH_MOD(OnDnsRequest, (recv_packet, packet));
+
+ for (auto &q : recv_packet.questions)
+ {
+ if (q.type == QUERY_AXFR)
+ {
+ ResourceRecord rr(q.name, QUERY_SOA);
+ packet->answers.push_back(rr);
+ break;
+ }
+ }
+
+ if (packet->answers.empty() && packet->authorities.empty() && packet->additional.empty() && packet->error == ERROR_NONE)
+ packet->error = ERROR_REFUSED; // usually safe, won't cause an NXDOMAIN to get cached
+
+ s->Reply(packet);
+ return true;
+ }
+
+ if (from == NULL)
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Received an answer over TCP. This is not supported.";
+ return true;
+ }
+ else if (this->addrs != *from)
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Received an answer from the wrong nameserver, Bad NAT or DNS forging attempt? '" << this->addrs.addr() << "' != '" << from->addr() << "'";
+ return true;
+ }
+
+ std::map<unsigned short, Request *>::iterator it = this->requests.find(recv_packet.id);
+ if (it == this->requests.end())
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Received an answer for something we didn't request";
+ return true;
+ }
+ Request *request = it->second;
+
+ if (recv_packet.flags & QUERYFLAGS_OPCODE)
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Received a nonstandard query";
+ recv_packet.error = ERROR_NONSTANDARD_QUERY;
+ request->OnError(&recv_packet);
+ }
+ else if (recv_packet.flags & QUERYFLAGS_RCODE)
+ {
+ Error error = ERROR_UNKNOWN;
+
+ switch (recv_packet.flags & QUERYFLAGS_RCODE)
+ {
+ case 1:
+ Log(LOG_DEBUG_2) << "Resolver: format error";
+ error = ERROR_FORMAT_ERROR;
+ break;
+ case 2:
+ Log(LOG_DEBUG_2) << "Resolver: server error";
+ error = ERROR_SERVER_FAILURE;
+ break;
+ case 3:
+ Log(LOG_DEBUG_2) << "Resolver: domain not found";
+ error = ERROR_DOMAIN_NOT_FOUND;
+ break;
+ case 4:
+ Log(LOG_DEBUG_2) << "Resolver: not implemented";
+ error = ERROR_NOT_IMPLEMENTED;
+ break;
+ case 5:
+ Log(LOG_DEBUG_2) << "Resolver: refused";
+ error = ERROR_REFUSED;
+ break;
+ default:
+ break;
+ }
+
+ recv_packet.error = error;
+ request->OnError(&recv_packet);
+ }
+ else if (recv_packet.questions.empty() || recv_packet.answers.empty())
+ {
+ Log(LOG_DEBUG_2) << "Resolver: No resource records returned";
+ recv_packet.error = ERROR_NO_RECORDS;
+ request->OnError(&recv_packet);
+ }
+ else
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Lookup complete for " << request->name;
+ request->OnLookupComplete(&recv_packet);
+ this->AddCache(recv_packet);
+ }
+
+ delete request;
+ return true;
+ }
+
+ void UpdateSerial() override
+ {
+ serial = Anope::CurTime;
+ }
+
+ void Notify(const Anope::string &zone) override
+ {
+ /* notify slaves of the update */
+ for (const auto &[ip, port] : notify)
+ {
+ sockaddrs addr;
+ addr.pton(ip.find(':') != Anope::string::npos ? AF_INET6 : AF_INET, ip, port);
+ if (!addr.valid())
+ return;
+
+ auto *packet = new Packet(this, &addr);
+ packet->flags = QUERYFLAGS_AA | QUERYFLAGS_OPCODE_NOTIFY;
+ try
+ {
+ packet->id = GetID();
+ }
+ catch (const SocketException &)
+ {
+ delete packet;
+ continue;
+ }
+
+ packet->questions.emplace_back(zone, QUERY_SOA);
+
+ new NotifySocket(ip.find(':') == Anope::string::npos ? AF_INET : AF_INET6, packet);
+ }
+ }
+
+ uint32_t GetSerial() const override
+ {
+ return serial;
+ }
+
+ void Tick() override
+ {
+ Log(LOG_DEBUG_2) << "Resolver: Purging DNS cache";
+
+ for (cache_map::iterator it = this->cache.begin(), it_next; it != this->cache.end(); it = it_next)
+ {
+ const Query &q = it->second;
+ const ResourceRecord &req = q.answers[0];
+ it_next = it;
+ ++it_next;
+
+ if (req.created + static_cast<time_t>(req.ttl) < Anope::CurTime)
+ this->cache.erase(it);
+ }
+ }
+
+private:
+ /** Add a record to the dns cache
+ * @param r The record
+ */
+ void AddCache(Query &r)
+ {
+ const ResourceRecord &rr = r.answers[0];
+ Log(LOG_DEBUG_3) << "Resolver cache: added cache for " << rr.name << " -> " << rr.rdata << ", ttl: " << rr.ttl;
+ this->cache[r.questions[0]] = r;
+ }
+
+ /** Check the DNS cache to see if request can be handled by a cached result
+ * @return true if a cached result was found.
+ */
+ bool CheckCache(Request *request)
+ {
+ cache_map::iterator it = this->cache.find(*request);
+ if (it != this->cache.end())
+ {
+ Query &record = it->second;
+ Log(LOG_DEBUG_3) << "Resolver: Using cached result for " << request->name;
+ request->OnLookupComplete(&record);
+ return true;
+ }
+
+ return false;
+ }
+
+};
+
+class ModuleDNS final
+ : public Module
+{
+ MyManager manager;
+
+ Anope::string nameserver;
+ Anope::string ip;
+ int port;
+
+ std::vector<std::pair<Anope::string, short> > notify;
+
+public:
+ ModuleDNS(const Anope::string &modname, const Anope::string &creator) : Module(modname, creator, EXTRA | VENDOR), manager(this)
+ {
+
+ }
+
+ ~ModuleDNS() override
+ {
+ for (std::map<int, Socket *>::const_iterator it = SocketEngine::Sockets.begin(), it_end = SocketEngine::Sockets.end(); it != it_end;)
+ {
+ Socket *s = it->second;
+ ++it;
+
+ if (dynamic_cast<NotifySocket *>(s) || dynamic_cast<TCPSocket::Client *>(s))
+ delete s;
+ }
+ }
+
+ void OnReload(Configuration::Conf *conf) override
+ {
+ Configuration::Block *block = conf->GetModule(this);
+
+ nameserver = block->Get<const Anope::string>("nameserver", "127.0.0.1");
+ timeout = block->Get<time_t>("timeout", "5");
+ ip = block->Get<const Anope::string>("ip", "0.0.0.0");
+ port = block->Get<int>("port", "53");
+ admin = block->Get<const Anope::string>("admin", "admin@example.com");
+ nameservers = block->Get<const Anope::string>("nameservers", "ns1.example.com");
+ refresh = block->Get<int>("refresh", "3600");
+
+ for (int i = 0; i < block->CountBlock("notify"); ++i)
+ {
+ Configuration::Block *n = block->GetBlock("notify", i);
+ Anope::string nip = n->Get<Anope::string>("ip");
+ short nport = n->Get<short>("port");
+
+ notify.emplace_back(nip, nport);
+ }
+
+ if (Anope::IsFile(nameserver))
+ {
+ std::ifstream f(nameserver.c_str());
+ bool success = false;
+
+ if (f.is_open())
+ {
+ for (Anope::string server; std::getline(f, server.str());)
+ {
+ if (server.find("nameserver") == 0)
+ {
+ size_t i = server.find_first_of("123456789");
+ if (i != Anope::string::npos)
+ {
+ if (server.substr(i).is_pos_number_only())
+ {
+ nameserver = server.substr(i);
+ Log(LOG_DEBUG) << "Nameserver set to " << nameserver;
+ success = true;
+ break;
+ }
+ }
+ }
+ }
+
+ f.close();
+ }
+
+ if (!success)
+ {
+ Log() << "Unable to find nameserver, defaulting to 127.0.0.1";
+ nameserver = "127.0.0.1";
+ }
+ }
+
+ try
+ {
+ this->manager.SetIPPort(nameserver, ip, port, notify);
+ }
+ catch (const SocketException &ex)
+ {
+ throw ModuleException(ex.GetReason());
+ }
+ }
+
+ void OnModuleUnload(User *u, Module *m) override
+ {
+ for (std::map<unsigned short, Request *>::iterator it = this->manager.requests.begin(), it_end = this->manager.requests.end(); it != it_end;)
+ {
+ unsigned short id = it->first;
+ Request *req = it->second;
+ ++it;
+
+ if (req->creator == m)
+ {
+ Query rr(*req);
+ rr.error = ERROR_UNLOADED;
+ req->OnError(&rr);
+
+ delete req;
+ this->manager.requests.erase(id);
+ }
+ }
+ }
+};
+
+MODULE_INIT(ModuleDNS)
generated by cgit (git 2.34.1) at 2025-06-16 18:48:49 +0000