X-Git-Url: https://git.netwichtig.de/gitweb/?a=blobdiff_plain;f=src%2Fdns.cpp;h=0e0f3287466e3931c003febfc1917e903fac6091;hb=6f4bf8ffd367f35b96265fea1ad01fb1acf2adcd;hp=3beb6b7c5811f60c54e02e8a858d0bb12b714ab3;hpb=e65b2c70e43882a8b4f31df78b5f9242140320f9;p=user%2Fhenk%2Fcode%2Finspircd.git diff --git a/src/dns.cpp b/src/dns.cpp index 3beb6b7c5..0e0f32874 100644 --- a/src/dns.cpp +++ b/src/dns.cpp @@ -16,127 +16,150 @@ /* dns.cpp - Nonblocking DNS functions. -Very loosely based on the firedns library, -Copyright (C) 2002 Ian Gulliver. - -There have been so many modifications to this file -to make it fit into InspIRCd and make it object -orientated that you should not take this code as -being what firedns really looks like. It used to -look very different to this! :-P +Very very loosely based on the firedns library, +Copyright (C) 2002 Ian Gulliver. This file is no +longer anything like firedns, there are many major +differences between this code and the original. +Please do not assume that firedns works like this, +looks like this, walks like this or tastes like this. */ using namespace std; -#include -#include #include #include #include -#include -#include #include #include -#include #include "dns.h" #include "inspircd.h" -#include "helperfuncs.h" -#include "inspircd_config.h" #include "socketengine.h" #include "configreader.h" +#include "socket.h" -extern InspIRCd* ServerInstance; -extern ServerConfig* Config; -extern time_t TIME; -extern userrec* fd_ref_table[MAX_DESCRIPTORS]; - -enum QueryType -{ - DNS_QRY_A = 1, - DNS_QRY_PTR = 12 -}; +using namespace std; +using irc::sockets::insp_sockaddr; +using irc::sockets::insp_inaddr; +using irc::sockets::insp_ntoa; +using irc::sockets::insp_aton; +/** Masks to mask off the responses we get from the DNSRequest methods + */ enum QueryInfo { - ERROR_MASK = 0x10000 + ERROR_MASK = 0x10000 /* Result is an error */ }; +/** Flags which can be ORed into a request or reply for different meanings + */ enum QueryFlags { - FLAGS_MASK_RD = 0x01, + FLAGS_MASK_RD = 0x01, /* Recursive */ FLAGS_MASK_TC = 0x02, - FLAGS_MASK_AA = 0x04, + FLAGS_MASK_AA = 0x04, /* Authoritative */ FLAGS_MASK_OPCODE = 0x78, FLAGS_MASK_QR = 0x80, - FLAGS_MASK_RCODE = 0x0F, + FLAGS_MASK_RCODE = 0x0F, /* Request */ FLAGS_MASK_Z = 0x70, FLAGS_MASK_RA = 0x80 }; -class dns_connection; -typedef std::map connlist; -typedef connlist::iterator connlist_iter; -DNS* Res = NULL; - -connlist connections; -int master_socket = -1; -Resolver* dns_classes[65536]; -insp_inaddr myserver; - -class dns_rr_middle +/** Represents a dns resource record (rr) + */ +class ResourceRecord { public: - QueryType type; - unsigned int rr_class; - unsigned long ttl; - unsigned int rdlength; + QueryType type; /* Record type */ + unsigned int rr_class; /* Record class */ + unsigned long ttl; /* Time to live */ + unsigned int rdlength; /* Record length */ }; -class dns_header +/** Represents a dns request/reply header, and its payload as opaque data. + */ +class DNSHeader { public: - unsigned char id[2]; - unsigned int flags1; - unsigned int flags2; + unsigned char id[2]; /* Request id */ + unsigned int flags1; /* Flags */ + unsigned int flags2; /* Flags */ unsigned int qdcount; - unsigned int ancount; - unsigned int nscount; + unsigned int ancount; /* Answer count */ + unsigned int nscount; /* Nameserver count */ unsigned int arcount; - unsigned char payload[512]; + unsigned char payload[512]; /* Packet payload */ }; -class dns_connection +class DNSRequest { public: - unsigned char id[2]; - unsigned char* res; - unsigned int rr_class; - QueryType type; + unsigned char id[2]; /* Request id */ + unsigned char* res; /* Result processing buffer */ + unsigned int rr_class; /* Request class */ + QueryType type; /* Request type */ + insp_inaddr myserver; /* DNS server address*/ + DNS* dnsobj; /* DNS caller (where we get our FD from) */ + + DNSRequest(InspIRCd* Instance, DNS* dns, insp_inaddr server, int id, requestlist &requests); + ~DNSRequest(); + DNSInfo ResultIsReady(DNSHeader &h, int length); + int SendRequests(const DNSHeader *header, const int length, QueryType qt); +}; - dns_connection() +class RequestTimeout : public InspTimer +{ + InspIRCd* ServerInstance; + DNSRequest* watch; + int watchid; + requestlist &rl; + public: + RequestTimeout(unsigned long n, InspIRCd* SI, DNSRequest* watching, int id, requestlist &requests) : InspTimer(n, time(NULL)), ServerInstance(SI), watch(watching), watchid(id), rl(requests) { - res = new unsigned char[512]; - *res = 0; + ServerInstance->Log(DEBUG, "New DNS timeout set on %08x", watching); } - ~dns_connection() + void Tick(time_t TIME) { - delete[] res; + if (rl.find(watchid) != rl.end()) + { + /* Still exists, whack it */ + if (rl.find(watchid)->second == watch) + { + if (ServerInstance->Res->Classes[watchid]) + { + ServerInstance->Res->Classes[watchid]->OnError(RESOLVER_TIMEOUT, "Request timed out"); + delete ServerInstance->Res->Classes[watchid]; + ServerInstance->Res->Classes[watchid] = NULL; + } + rl.erase(rl.find(watchid)); + delete watch; + ServerInstance->Log(DEBUG, "DNS timeout on %08x squished pointer", watch); + } + return; + } + ServerInstance->Log(DEBUG, "DNS timeout on %08x: result already received!", watch); } - - DNSInfo result_ready(dns_header &h, int length); - int send_requests(const dns_header *header, const int length, QueryType qt); }; -/* - * Optimized by brain, these were using integer division and modulus. - * We can use logic shifts and logic AND to replace these even divisions - * and multiplications, it should be a bit faster (probably not noticably, - * but of course, more impressive). Also made these inline. - */ +/* Allocate the processing buffer */ +DNSRequest::DNSRequest(InspIRCd* Instance, DNS* dns, insp_inaddr server, int id, requestlist &requests) : dnsobj(dns) +{ + res = new unsigned char[512]; + *res = 0; + memcpy(&myserver, &server, sizeof(insp_inaddr)); + RequestTimeout* RT = new RequestTimeout(Instance->Config->dns_timeout ? Instance->Config->dns_timeout : 5, Instance, this, id, requests); + Instance->Timers->AddTimer(RT); /* The timer manager frees this */ +} -inline void dns_fill_rr(dns_rr_middle* rr, const unsigned char *input) +/* Deallocate the processing buffer */ +DNSRequest::~DNSRequest() +{ + delete[] res; +} + +/** Fill a ResourceRecord class based on raw data input */ +inline void DNS::FillResourceRecord(ResourceRecord* rr, const unsigned char *input) { rr->type = (QueryType)((input[0] << 8) + input[1]); rr->rr_class = (input[2] << 8) + input[3]; @@ -144,7 +167,8 @@ inline void dns_fill_rr(dns_rr_middle* rr, const unsigned char *input) rr->rdlength = (input[8] << 8) + input[9]; } -inline void dns_fill_header(dns_header *header, const unsigned char *input, const int length) +/** Fill a DNSHeader class based on raw data input of a given length */ +inline void DNS::FillHeader(DNSHeader *header, const unsigned char *input, const int length) { header->id[0] = input[0]; header->id[1] = input[1]; @@ -157,7 +181,8 @@ inline void dns_fill_header(dns_header *header, const unsigned char *input, cons memcpy(header->payload,&input[12],length); } -inline void dns_empty_header(unsigned char *output, const dns_header *header, const int length) +/** Empty a DNSHeader class out into raw data, ready for transmission */ +inline void DNS::EmptyHeader(unsigned char *output, const DNSHeader *header, const int length) { output[0] = header->id[0]; output[1] = header->id[1]; @@ -174,41 +199,52 @@ inline void dns_empty_header(unsigned char *output, const dns_header *header, co memcpy(&output[12],header->payload,length); } - -int dns_connection::send_requests(const dns_header *header, const int length, QueryType qt) +/** Send requests we have previously built down the UDP socket */ +int DNSRequest::SendRequests(const DNSHeader *header, const int length, QueryType qt) { insp_sockaddr addr; - unsigned char payload[sizeof(dns_header)]; + unsigned char payload[sizeof(DNSHeader)]; this->rr_class = 1; this->type = qt; - dns_empty_header(payload,header,length); + DNS::EmptyHeader(payload,header,length); memset(&addr,0,sizeof(addr)); #ifdef IPV6 memcpy(&addr.sin6_addr,&myserver,sizeof(addr.sin6_addr)); addr.sin6_family = AF_FAMILY; - addr.sin6_port = htons(53); + addr.sin6_port = htons(DNS::QUERY_PORT); #else memcpy(&addr.sin_addr.s_addr,&myserver,sizeof(addr.sin_addr)); addr.sin_family = AF_FAMILY; - addr.sin_port = htons(53); + addr.sin_port = htons(DNS::QUERY_PORT); #endif - if (sendto(master_socket, payload, length + 12, 0, (sockaddr *) &addr, sizeof(addr)) == -1) - { - log(DEBUG,"Error in sendto!"); + if (sendto(dnsobj->GetFd(), payload, length + 12, 0, (sockaddr *) &addr, sizeof(addr)) == -1) return -1; - } return 0; } -dns_connection* dns_add_query(dns_header *header, int &id) +/** Add a query with a predefined header, and allocate an ID for it. */ +DNSRequest* DNS::AddQuery(DNSHeader *header, int &id) { + /* Is the DNS connection down? */ + if (this->GetFd() == -1) + return NULL; + + /* Are there already the max number of requests on the go? */ + if (requests.size() == DNS::MAX_REQUEST_ID + 1) + return NULL; + + /* Create an id */ + id = this->PRNG() & DNS::MAX_REQUEST_ID; + + /* If this id is already 'in flight', pick another. */ + while (requests.find(id) != requests.end()) + id = this->PRNG() & DNS::MAX_REQUEST_ID; - id = rand() % 65536; - dns_connection* req = new dns_connection(); + DNSRequest* req = new DNSRequest(ServerInstance, this, this->myserver, id, requests); header->id[0] = req->id[0] = id >> 8; header->id[1] = req->id[1] = id & 0xFF; @@ -219,41 +255,84 @@ dns_connection* dns_add_query(dns_header *header, int &id) header->nscount = 0; header->arcount = 0; - if (connections.find(id) == connections.end()) - connections[id] = req; + /* At this point we already know the id doesnt exist, + * so there needs to be no second check for the ::end() + */ + requests[id] = req; /* According to the C++ spec, new never returns NULL. */ return req; } -void create_socket() +/** Initialise the DNS UDP socket so that we can send requests */ +DNS::DNS(InspIRCd* Instance) : ServerInstance(Instance) { - log(DEBUG,"---- BEGIN DNS INITIALIZATION, SERVER=%s ---",Config->DNSServer); + ServerInstance->Log(DEBUG,"DNS::DNS: Instance = %08x",Instance); + insp_inaddr addr; - srand((unsigned int) TIME); + + /* Clear the Resolver class table */ + memset(Classes,0,sizeof(Classes)); + + /* Set the id of the next request to 0 + */ + currid = 0; + + /* By default we're not munging ip's + */ + ip6munge = false; + + /* Clear the namesever address */ memset(&myserver,0,sizeof(insp_inaddr)); - if (insp_aton(Config->DNSServer,&addr) > 0) + + /* Convert the nameserver address into an insp_inaddr */ + if (insp_aton(ServerInstance->Config->DNSServer,&addr) > 0) + { memcpy(&myserver,&addr,sizeof(insp_inaddr)); + if ((strstr(ServerInstance->Config->DNSServer,"::ffff:") == (char*)&ServerInstance->Config->DNSServer) || (strstr(ServerInstance->Config->DNSServer,"::FFFF:") == (char*)&ServerInstance->Config->DNSServer)) + { + /* These dont come back looking like they did when they went in. + * We're forced to turn some checks off. + * If anyone knows how to fix this, let me know. --Brain + */ + ServerInstance->Log(DEFAULT,"WARNING: Using IPv4 addresses over IPv6 forces some DNS checks to be disabled."); + ServerInstance->Log(DEFAULT," This should not cause a problem, however it is recommended you migrate"); + ServerInstance->Log(DEFAULT," to a true IPv6 environment."); + this->ip6munge = true; + } + ServerInstance->Log(DEBUG,"Added nameserver '%s'",ServerInstance->Config->DNSServer); + } + else + { + ServerInstance->Log(DEBUG,"GACK! insp_aton says the nameserver '%s' is invalid!",ServerInstance->Config->DNSServer); + } - master_socket = socket(PF_PROTOCOL, SOCK_DGRAM, 0); - if (master_socket != -1) + /* Initialize mastersocket */ + this->SetFd(socket(PF_PROTOCOL, SOCK_DGRAM, 0)); + if (this->GetFd() != -1) { - log(DEBUG,"Set query socket nonblock"); - if (fcntl(master_socket, F_SETFL, O_NONBLOCK) != 0) + /* Did it succeed? */ + if (fcntl(this->GetFd(), F_SETFL, O_NONBLOCK) != 0) { - shutdown(master_socket,2); - close(master_socket); - master_socket = -1; + /* Couldn't make the socket nonblocking */ + shutdown(this->GetFd(),2); + close(this->GetFd()); + this->SetFd(-1); } } - if (master_socket != -1) + else + { + ServerInstance->Log(DEBUG,"I cant socket() this socket! (%s)",strerror(errno)); + } + /* Have we got a socket and is it nonblocking? */ + if (this->GetFd() != -1) { #ifdef IPV6 insp_sockaddr addr; memset(&addr,0,sizeof(addr)); addr.sin6_family = AF_FAMILY; addr.sin6_port = 0; - memset(&addr.sin6_addr,255,sizeof(in6_addr)); + addr.sin6_addr = in6addr_any; #else insp_sockaddr addr; memset(&addr,0,sizeof(addr)); @@ -261,179 +340,402 @@ void create_socket() addr.sin_port = 0; addr.sin_addr.s_addr = INADDR_ANY; #endif - log(DEBUG,"Binding query port"); - if (bind(master_socket,(sockaddr *)&addr,sizeof(addr)) != 0) + /* Bind the port */ + if (bind(this->GetFd(),(sockaddr *)&addr,sizeof(addr)) != 0) { - log(DEBUG,"Cant bind with source port = 0"); - shutdown(master_socket,2); - close(master_socket); - master_socket = -1; + /* Failed to bind */ + ServerInstance->Log(DEBUG,"Cant bind DNS fd"); + shutdown(this->GetFd(),2); + close(this->GetFd()); + this->SetFd(-1); } - if (master_socket >= 0) + if (this->GetFd() >= 0) { - log(DEBUG,"Attach query port to socket engine"); + ServerInstance->Log(DEBUG,"Add master socket %d",this->GetFd()); + /* Hook the descriptor into the socket engine */ if (ServerInstance && ServerInstance->SE) - ServerInstance->SE->AddFd(master_socket,true,X_ESTAB_DNS); + { + if (!ServerInstance->SE->AddFd(this)) + { + ServerInstance->Log(DEFAULT,"Internal error starting DNS - hostnames will NOT resolve."); + shutdown(this->GetFd(),2); + close(this->GetFd()); + this->SetFd(-1); + } + } } } } -int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short rr_class, unsigned char * const payload) +/** Build a payload to be placed after the header, based upon input data, a resource type, a class and a pointer to a buffer */ +int DNS::MakePayload(const char * const name, const QueryType rr, const unsigned short rr_class, unsigned char * const payload) { - short payloadpos; - const char * tempchr, * tempchr2; - unsigned short l; - - payloadpos = 0; - tempchr2 = name; + short payloadpos = 0; + const char* tempchr, *tempchr2 = name; + unsigned short length; /* split name up into labels, create query */ while ((tempchr = strchr(tempchr2,'.')) != NULL) { - l = tempchr - tempchr2; - if (payloadpos + l + 1 > 507) + length = tempchr - tempchr2; + if (payloadpos + length + 1 > 507) return -1; - payload[payloadpos++] = l; - memcpy(&payload[payloadpos],tempchr2,l); - payloadpos += l; + payload[payloadpos++] = length; + memcpy(&payload[payloadpos],tempchr2,length); + payloadpos += length; tempchr2 = &tempchr[1]; } - l = strlen(tempchr2); - if (l) + length = strlen(tempchr2); + if (length) { - if (payloadpos + l + 2 > 507) + if (payloadpos + length + 2 > 507) return -1; - payload[payloadpos++] = l; - memcpy(&payload[payloadpos],tempchr2,l); - payloadpos += l; - payload[payloadpos++] = '\0'; + payload[payloadpos++] = length; + memcpy(&payload[payloadpos],tempchr2,length); + payloadpos += length; + payload[payloadpos++] = 0; } if (payloadpos > 508) return -1; - l = htons(rr); - memcpy(&payload[payloadpos],&l,2); - l = htons(rr_class); - memcpy(&payload[payloadpos + 2],&l,2); + length = htons(rr); + memcpy(&payload[payloadpos],&length,2); + length = htons(rr_class); + memcpy(&payload[payloadpos + 2],&length,2); return payloadpos + 4; } -int DNS::dns_getip(const char *name) +/** Start lookup of an hostname to an IP address */ +int DNS::GetIP(const char *name) { - dns_header h; + DNSHeader h; int id; int length; - dns_connection* req; - if ((length = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char*)&h.payload)) == -1) + if ((length = this->MakePayload(name, DNS_QUERY_A, 1, (unsigned char*)&h.payload)) == -1) return -1; - req = dns_add_query(&h, id); + DNSRequest* req = this->AddQuery(&h, id); - if (req->send_requests(&h,length,DNS_QRY_A) == -1) + if ((!req) || (req->SendRequests(&h, length, DNS_QUERY_A) == -1)) return -1; return id; } -int DNS::dns_getname(const insp_inaddr *ip) +/** Start lookup of an hostname to an IPv6 address */ +int DNS::GetIP6(const char *name) { -#ifdef IPV6 - return -1; -#else - char query[29]; - dns_header h; + DNSHeader h; int id; int length; - dns_connection* req; - unsigned char* c = (unsigned char*)&ip->s_addr; + if ((length = this->MakePayload(name, DNS_QUERY_AAAA, 1, (unsigned char*)&h.payload)) == -1) + return -1; + DNSRequest* req = this->AddQuery(&h, id); + + if ((!req) || (req->SendRequests(&h, length, DNS_QUERY_AAAA) == -1)) + return -1; + + return id; +} + +/** Start lookup of a cname to another name */ +int DNS::GetCName(const char *alias) +{ + DNSHeader h; + int id; + int length; + + if ((length = this->MakePayload(alias, DNS_QUERY_CNAME, 1, (unsigned char*)&h.payload)) == -1) + return -1; + + DNSRequest* req = this->AddQuery(&h, id); + + if ((!req) || (req->SendRequests(&h, length, DNS_QUERY_CNAME) == -1)) + return -1; + + return id; +} + +/** Start lookup of an IP address to a hostname */ +int DNS::GetName(const insp_inaddr *ip) +{ + char query[128]; + DNSHeader h; + int id; + int length; + +#ifdef IPV6 + unsigned char* c = (unsigned char*)&ip->s6_addr; + if (c[0] == 0 && c[1] == 0 && c[2] == 0 && c[3] == 0 && + c[4] == 0 && c[5] == 0 && c[6] == 0 && c[7] == 0 && + c[8] == 0 && c[9] == 0 && c[10] == 0xFF && c[11] == 0xFF) + sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[15],c[14],c[13],c[12]); + else + DNS::MakeIP6Int(query, (in6_addr*)ip); +#else + unsigned char* c = (unsigned char*)&ip->s_addr; sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[3],c[2],c[1],c[0]); +#endif - if ((length = dns_build_query_payload(query,DNS_QRY_PTR,1,(unsigned char*)&h.payload)) == -1) + if ((length = this->MakePayload(query, DNS_QUERY_PTR, 1, (unsigned char*)&h.payload)) == -1) return -1; - req = dns_add_query(&h, id); + DNSRequest* req = this->AddQuery(&h, id); - if (req->send_requests(&h,length,DNS_QRY_PTR) == -1) + if ((!req) || (req->SendRequests(&h, length, DNS_QUERY_PTR) == -1)) return -1; return id; +} + +/** Start lookup of an IP address to a hostname */ +int DNS::GetNameForce(const char *ip, ForceProtocol fp) +{ + char query[128]; + DNSHeader h; + int id; + int length; +#ifdef SUPPORT_IP6LINKS + if (fp == PROTOCOL_IPV6) + { + in6_addr i; + if (inet_pton(AF_INET6, ip, &i) > 0) + { + DNS::MakeIP6Int(query, &i); + } + else + /* Invalid IP address */ + return -1; + } + else #endif + { + in_addr i; + if (inet_aton(ip, &i)) + { + unsigned char* c = (unsigned char*)&i.s_addr; + sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[3],c[2],c[1],c[0]); + } + else + /* Invalid IP address */ + return -1; + } + + ServerInstance->Log(DEBUG,"DNS::GetNameForce: %s %d",query, fp); + + if ((length = this->MakePayload(query, DNS_QUERY_PTR, 1, (unsigned char*)&h.payload)) == -1) + return -1; + + DNSRequest* req = this->AddQuery(&h, id); + + if ((!req) || (req->SendRequests(&h, length, DNS_QUERY_PTR) == -1)) + return -1; + + return id; } -/* Return the next id which is ready, and the result attached to it +/** Build an ipv6 reverse domain from an in6_addr */ -DNSResult DNS::dns_getresult() +void DNS::MakeIP6Int(char* query, const in6_addr *ip) { - /* retrieve result of DNS query (buffered) */ - dns_header header; - dns_connection *req; - int length; - unsigned char buffer[sizeof(dns_header)]; +#ifdef SUPPORT_IP6LINKS + const char* hex = "0123456789abcdef"; + for (int index = 31; index >= 0; index--) /* for() loop steps twice per byte */ + { + if (index % 2) + /* low nibble */ + *query++ = hex[ip->s6_addr[index / 2] & 0x0F]; + else + /* high nibble */ + *query++ = hex[(ip->s6_addr[index / 2] & 0xF0) >> 4]; + *query++ = '.'; /* Seperator */ + } + strcpy(query,"ip6.arpa"); /* Suffix the string */ +#else + *query = 0; +#endif +} - length = recv(master_socket,buffer,sizeof(dns_header),0); +/** Return the next id which is ready, and the result attached to it */ +DNSResult DNS::GetResult() +{ + /* Fetch dns query response and decide where it belongs */ + DNSHeader header; + DNSRequest *req; + unsigned char buffer[sizeof(DNSHeader)]; + sockaddr from; + socklen_t x = sizeof(from); + const char* ipaddr_from = ""; + unsigned short int port_from = 0; + int length = recvfrom(this->GetFd(),buffer,sizeof(DNSHeader),0,&from,&x); + + if (length < 0) + ServerInstance->Log(DEBUG,"Error in recvfrom()! (%s)",strerror(errno)); + + /* Did we get the whole header? */ if (length < 12) + { + /* Nope - something screwed up. */ + ServerInstance->Log(DEBUG,"Whole header not read!"); return std::make_pair(-1,""); + } - dns_fill_header(&header,buffer,length - 12); + /* Check wether the reply came from a different DNS + * server to the one we sent it to, or the source-port + * is not 53. + * A user could in theory still spoof dns packets anyway + * but this is less trivial than just sending garbage + * to the client, which is possible without this check. + * + * -- Thanks jilles for pointing this one out. + */ +#ifdef IPV6 + ipaddr_from = insp_ntoa(((sockaddr_in6*)&from)->sin6_addr); + port_from = ntohs(((sockaddr_in6*)&from)->sin6_port); +#else + ipaddr_from = insp_ntoa(((sockaddr_in*)&from)->sin_addr); + port_from = ntohs(((sockaddr_in*)&from)->sin_port); +#endif - // Get the id of this request + /* We cant perform this security check if you're using 4in6. + * Tough luck to you, choose one or't other! + */ + if (!ip6munge) + { + if ((port_from != DNS::QUERY_PORT) || (strcasecmp(ipaddr_from, ServerInstance->Config->DNSServer))) + { + ServerInstance->Log(DEBUG,"port %d is not 53, or %s is not %s",port_from, ipaddr_from, ServerInstance->Config->DNSServer); + return std::make_pair(-1,""); + } + } + + /* Put the read header info into a header class */ + DNS::FillHeader(&header,buffer,length - 12); + + /* Get the id of this request. + * Its a 16 bit value stored in two char's, + * so we use logic shifts to create the value. + */ unsigned long this_id = header.id[1] + (header.id[0] << 8); - // Do we have a pending request for it? - - connlist_iter n_iter = connections.find(this_id); - if (n_iter == connections.end()) - { - log(DEBUG,"DNS: got a response for a query we didnt send with fd=%d queryid=%d",master_socket,this_id); - return std::make_pair(-1,""); - } - else - { - /* Remove the query from the list */ - req = (dns_connection*)n_iter->second; - /* We don't delete c here, because its done later when needed */ - connections.erase(n_iter); - } - DNSInfo data = req->result_ready(header, length); + /* Do we have a pending request matching this id? */ + requestlist_iter n_iter = requests.find(this_id); + if (n_iter == requests.end()) + { + /* Somehow we got a DNS response for a request we never made... */ + ServerInstance->Log(DEBUG,"DNS: got a response for a query we didnt send with fd=%d queryid=%d",this->GetFd(),this_id); + return std::make_pair(-1,""); + } + else + { + /* Remove the query from the list of pending queries */ + req = (DNSRequest*)n_iter->second; + requests.erase(n_iter); + } + + /* Inform the DNSRequest class that it has a result to be read. + * When its finished it will return a DNSInfo which is a pair of + * unsigned char* resource record data, and an error message. + */ + DNSInfo data = req->ResultIsReady(header, length); std::string resultstr; + /* Check if we got a result, if we didnt, its an error */ if (data.first == NULL) { + /* An error. + * Mask the ID with the value of ERROR_MASK, so that + * the dns_deal_with_classes() function knows that its + * an error response and needs to be treated uniquely. + * Put the error message in the second field. + */ delete req; return std::make_pair(this_id | ERROR_MASK, data.second); } else { - if (req->type == DNS_QRY_A) - { - char formatted[16]; - snprintf(formatted,16,"%u.%u.%u.%u",data.first[0],data.first[1],data.first[2],data.first[3]); - resultstr = formatted; - } - else + char formatted[128]; + + /* Forward lookups come back as binary data. We must format them into ascii */ + switch (req->type) { - resultstr = std::string((const char*)data.first); + case DNS_QUERY_A: + snprintf(formatted,16,"%u.%u.%u.%u",data.first[0],data.first[1],data.first[2],data.first[3]); + resultstr = formatted; + break; + + case DNS_QUERY_AAAA: + { + snprintf(formatted,40,"%x:%x:%x:%x:%x:%x:%x:%x", + (ntohs(data.first[0]) + ntohs(data.first[1] << 8)), + (ntohs(data.first[2]) + ntohs(data.first[3] << 8)), + (ntohs(data.first[4]) + ntohs(data.first[5] << 8)), + (ntohs(data.first[6]) + ntohs(data.first[7] << 8)), + (ntohs(data.first[8]) + ntohs(data.first[9] << 8)), + (ntohs(data.first[10]) + ntohs(data.first[11] << 8)), + (ntohs(data.first[12]) + ntohs(data.first[13] << 8)), + (ntohs(data.first[14]) + ntohs(data.first[15] << 8))); + char* c = strstr(formatted,":0:"); + if (c != NULL) + { + 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); + } + resultstr = formatted; + + /* Special case. Sending ::1 around between servers + * and to clients is dangerous, because the : on the + * start makes the client or server interpret the IP + * as the last parameter on the line with a value ":1". + */ + if (*formatted == ':') + resultstr = "0" + resultstr; + } + break; + + case DNS_QUERY_CNAME: + /* Identical handling to PTR */ + + case DNS_QUERY_PTR: + /* Reverse lookups just come back as char* */ + resultstr = std::string((const char*)data.first); + break; + + default: + ServerInstance->Log(DEBUG,"WARNING: Somehow we made a request for a DNS_QUERY_PTR4 or DNS_QUERY_PTR6, but these arent real rr types!"); + break; + } + /* Build the reply with the id and hostname/ip in it */ delete req; return std::make_pair(this_id,resultstr); } } -/** A result is ready, process it - */ -DNSInfo dns_connection::result_ready(dns_header &header, int length) +/** A result is ready, process it */ +DNSInfo DNSRequest::ResultIsReady(DNSHeader &header, int length) { int i = 0; int q = 0; int curanswer, o; - dns_rr_middle rr; - unsigned short p; - + ResourceRecord rr; + unsigned short ptr; + + /* This is just to keep _FORTIFY_SOURCE happy */ + rr.type = DNS_QUERY_NONE; + rr.rdlength = 0; + if (!(header.flags1 & FLAGS_MASK_QR)) return std::make_pair((unsigned char*)NULL,"Not a query result"); @@ -441,12 +743,14 @@ DNSInfo dns_connection::result_ready(dns_header &header, int length) return std::make_pair((unsigned char*)NULL,"Unexpected value in DNS reply packet"); if (header.flags2 & FLAGS_MASK_RCODE) - return std::make_pair((unsigned char*)NULL,"Internal server error (SERVFAIL)"); + return std::make_pair((unsigned char*)NULL,"Domain name not found"); if (header.ancount < 1) return std::make_pair((unsigned char*)NULL,"No resource records returned"); + /* Subtract the length of the header from the length of the packet */ length -= 12; + while ((unsigned int)q < header.qdcount && i < length) { if (header.payload[i] > 63) @@ -488,7 +792,7 @@ DNSInfo dns_connection::result_ready(dns_header &header, int length) if (length - i < 10) return std::make_pair((unsigned char*)NULL,"Incorrectly sized DNS reply"); - dns_fill_rr(&rr,&header.payload[i]); + DNS::FillResourceRecord(&rr,&header.payload[i]); i += 10; if (rr.type != this->type) { @@ -515,15 +819,17 @@ DNSInfo dns_connection::result_ready(dns_header &header, int length) switch (rr.type) { - case DNS_QRY_PTR: + case DNS_QUERY_CNAME: + /* CNAME and PTR have the same processing code */ + case DNS_QUERY_PTR: o = 0; q = 0; while (q == 0 && i < length && o + 256 < 1023) { if (header.payload[i] > 63) { - memcpy(&p,&header.payload[i],2); - i = ntohs(p) - 0xC000 - 12; + memcpy(&ptr,&header.payload[i],2); + i = ntohs(ptr) - 0xC000 - 12; } else { @@ -533,7 +839,7 @@ DNSInfo dns_connection::result_ready(dns_header &header, int length) } else { - res[o] = '\0'; + res[o] = 0; if (o != 0) res[o++] = '.'; memcpy(&res[o],&header.payload[i + 1],header.payload[i]); @@ -542,144 +848,218 @@ DNSInfo dns_connection::result_ready(dns_header &header, int length) } } } - res[o] = '\0'; + res[o] = 0; break; - case DNS_QRY_A: + case DNS_QUERY_AAAA: memcpy(res,&header.payload[i],rr.rdlength); - res[rr.rdlength] = '\0'; - break; + res[rr.rdlength] = 0; + break; + case DNS_QUERY_A: + memcpy(res,&header.payload[i],rr.rdlength); + res[rr.rdlength] = 0; + break; default: memcpy(res,&header.payload[i],rr.rdlength); - res[rr.rdlength] = '\0'; - break; + res[rr.rdlength] = 0; + break; } return std::make_pair(res,"No error");; } -DNS::DNS() -{ -} - +/** Close the master socket */ DNS::~DNS() { + shutdown(this->GetFd(), 2); + close(this->GetFd()); } -Resolver::Resolver(const std::string &source, bool forward) : input(source), fwd(forward) +/** High level abstraction of dns used by application at large */ +Resolver::Resolver(InspIRCd* Instance, const std::string &source, QueryType qt, Module* creator) : ServerInstance(Instance), Creator(creator), input(source), querytype(qt) { - if (forward) - { - log(DEBUG,"Resolver: Forward lookup on %s",source.c_str()); - this->myid = Res->dns_getip(source.c_str()); - } - else + ServerInstance->Log(DEBUG,"Instance: %08x %08x",Instance, ServerInstance); + + insp_inaddr binip; + + switch (querytype) { - log(DEBUG,"Resolver: Reverse lookup on %s",source.c_str()); - insp_inaddr binip; - if (insp_aton(source.c_str(), &binip) > 0) - { - /* Valid ip address */ - this->myid = Res->dns_getname(&binip); - } - else - { - this->OnError(RESOLVER_BADIP, "Bad IP address for reverse lookup"); - throw ModuleException("Resolver: Bad IP address"); - return; - } + case DNS_QUERY_A: + this->myid = ServerInstance->Res->GetIP(source.c_str()); + break; + + case DNS_QUERY_PTR: + if (insp_aton(source.c_str(), &binip) > 0) + { + /* Valid ip address */ + this->myid = ServerInstance->Res->GetName(&binip); + } + else + { + this->OnError(RESOLVER_BADIP, "Bad IP address for reverse lookup"); + throw ModuleException("Resolver: Bad IP address"); + return; + } + break; + + case DNS_QUERY_PTR4: + querytype = DNS_QUERY_PTR; + this->myid = ServerInstance->Res->GetNameForce(source.c_str(), PROTOCOL_IPV4); + break; + + case DNS_QUERY_PTR6: + querytype = DNS_QUERY_PTR; + this->myid = ServerInstance->Res->GetNameForce(source.c_str(), PROTOCOL_IPV6); + break; + + case DNS_QUERY_AAAA: + this->myid = ServerInstance->Res->GetIP6(source.c_str()); + break; + + case DNS_QUERY_CNAME: + this->myid = ServerInstance->Res->GetCName(source.c_str()); + break; + + default: + this->myid = -1; + break; } if (this->myid == -1) { - log(DEBUG,"Resolver::Resolver: Could not get an id!"); + ServerInstance->Log(DEBUG,"Resolver::Resolver: Could not get an id!"); this->OnError(RESOLVER_NSDOWN, "Nameserver is down"); throw ModuleException("Resolver: Couldnt get an id to make a request"); /* We shouldnt get here really */ return; } - log(DEBUG,"Resolver::Resolver: this->myid=%d",this->myid); + ServerInstance->Log(DEBUG,"Resolver::Resolver: this->myid=%d",this->myid); } -//void Resolver::OnLookupComplete(const std::string &result) -//{ -//} - +/** Called when an error occurs */ void Resolver::OnError(ResolverError e, const std::string &errormessage) { + /* Nothing in here */ } +/** Destroy a resolver */ Resolver::~Resolver() { - log(DEBUG,"Resolver::~Resolver"); + /* Nothing here (yet) either */ } +/** Get the request id associated with this class */ int Resolver::GetId() { return this->myid; } -void dns_deal_with_classes(int fd) +Module* Resolver::GetCreator() { - log(DEBUG,"dns_deal_with_classes(%d)",fd); - if (fd == master_socket) + return this->Creator; +} + +/** Process a socket read event */ +void DNS::HandleEvent(EventType et, int errornum) +{ + ServerInstance->Log(DEBUG,"Marshall reads: %d",this->GetFd()); + /* Fetch the id and result of the next available packet */ + DNSResult res = this->GetResult(); + /* Is there a usable request id? */ + if (res.first != -1) { - DNSResult res = Res->dns_getresult(); - if (res.first != -1) + /* Its an error reply */ + if (res.first & ERROR_MASK) { - if (res.first & ERROR_MASK) + /* Mask off the error bit */ + res.first -= ERROR_MASK; + /* Marshall the error to the correct class */ + ServerInstance->Log(DEBUG,"Error available, id=%d",res.first); + if (Classes[res.first]) { - res.first -= ERROR_MASK; - - log(DEBUG,"Error available, id=%d",res.first); - if (dns_classes[res.first]) - { - dns_classes[res.first]->OnError(RESOLVER_NXDOMAIN, res.second); - delete dns_classes[res.first]; - dns_classes[res.first] = NULL; - } + if (ServerInstance && ServerInstance->stats) + ServerInstance->stats->statsDnsBad++; + Classes[res.first]->OnError(RESOLVER_NXDOMAIN, res.second); + delete Classes[res.first]; + Classes[res.first] = NULL; } - else + } + else + { + /* It is a non-error result */ + ServerInstance->Log(DEBUG,"Result available, id=%d",res.first); + /* Marshall the result to the correct class */ + if (Classes[res.first]) { - log(DEBUG,"Result available, id=%d",res.first); - if (dns_classes[res.first]) - { - dns_classes[res.first]->OnLookupComplete(res.second); - delete dns_classes[res.first]; - dns_classes[res.first] = NULL; - } + if (ServerInstance && ServerInstance->stats) + ServerInstance->stats->statsDnsGood++; + Classes[res.first]->OnLookupComplete(res.second); + delete Classes[res.first]; + Classes[res.first] = NULL; } } + + if (ServerInstance && ServerInstance->stats) + ServerInstance->stats->statsDns++; } } -bool dns_add_class(Resolver* r) +/** Add a derived Resolver to the working set */ +bool DNS::AddResolverClass(Resolver* r) { - log(DEBUG,"dns_add_class"); + /* Check the pointers validity and the id's validity */ if ((r) && (r->GetId() > -1)) { - if (!dns_classes[r->GetId()]) + /* Check the slot isnt already occupied - + * This should NEVER happen unless we have + * a severely broken DNS server somewhere + */ + if (!Classes[r->GetId()]) { - log(DEBUG,"dns_add_class: added class"); - dns_classes[r->GetId()] = r; + /* Set up the pointer to the class */ + Classes[r->GetId()] = r; return true; } else - { - log(DEBUG,"Space occupied!"); + /* Duplicate id */ return false; - } } else { - log(DEBUG,"Bad class"); - delete r; - return true; + /* Pointer or id not valid. + * Free the item and return + */ + if (r) + delete r; + + return false; + } +} + +void DNS::CleanResolvers(Module* module) +{ + for (int i = 0; i < MAX_REQUEST_ID; i++) + { + if (Classes[i]) + { + if (Classes[i]->GetCreator() == module) + { + Classes[i]->OnError(RESLOVER_FORCEUNLOAD, "Parent module is unloading"); + delete Classes[i]; + Classes[i] = NULL; + } + } } } -void init_dns() +/** Generate pseudo-random number */ +unsigned long DNS::PRNG() { - Res = new DNS(); - memset(dns_classes,0,sizeof(dns_classes)); - create_socket(); + unsigned long val = 0; + timeval n; + serverstats* s = ServerInstance->stats; + gettimeofday(&n,NULL); + val = (n.tv_usec ^ getpid() ^ geteuid() ^ (this->currid++)) ^ s->statsAccept + n.tv_sec; + val = val + s->statsCollisions ^ s->statsDnsGood - s->statsDnsBad; + val += (s->statsConnects ^ (unsigned long)s->statsSent ^ (unsigned long)s->statsRecv) - s->BoundPortCount; + return val; }