#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(DNS::GetMasterSocket(), payload, length + 12, 0, (sockaddr *) &addr, sizeof(addr)) == -1)
{
- log(DEBUG,"Error in sendto!");
+ log(DEBUG,"Error in sendto! (%s)",strerror(errno));
return -1;
}
/* Add a query with a predefined header, and allocate an ID for it. */
DNSRequest* DNS::AddQuery(DNSHeader *header, int &id)
{
- id = rand() % 65536;
+ /* 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;
+
DNSRequest* req = new DNSRequest(this->myserver);
header->id[0] = req->id[0] = id >> 8;
header->nscount = 0;
header->arcount = 0;
- if (requests.find(id) == requests.end())
- requests[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;
/* Clear the Resolver class table */
memset(Classes,0,sizeof(Classes));
- /* Seed random number generator, we use this to generate
- * dns packet id's
+ /* Set the id of the next request to 0
*/
- srand((unsigned int)time(NULL));
+ currid = 0;
/* Clear the namesever address */
memset(&myserver,0,sizeof(insp_inaddr));
/* Convert the nameserver address into an insp_inaddr */
if (insp_aton(Config->DNSServer,&addr) > 0)
+ {
memcpy(&myserver,&addr,sizeof(insp_inaddr));
+ if ((strstr(Config->DNSServer,"::ffff:") == (char*)&Config->DNSServer) || (strstr(Config->DNSServer,"::FFFF:") == (char*)&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
+ */
+ log(DEFAULT,"WARNING: Using IPv4 addresses over IPv6 forces some DNS checks to be disabled.");
+ log(DEFAULT," This should not cause a problem, however it is recommended you migrate");
+ log(DEFAULT," to a true IPv6 environment.");
+ this->ip6munge = true;
+ }
+ log(DEBUG,"Added nameserver '%s'",Config->DNSServer);
+ }
+ else
+ {
+ log(DEBUG,"GACK! insp_aton says the nameserver '%s' is invalid!",Config->DNSServer);
+ }
/* Initialize mastersocket */
MasterSocket = socket(PF_PROTOCOL, SOCK_DGRAM, 0);
MasterSocket = -1;
}
}
+ else
+ {
+ log(DEBUG,"I cant socket() this socket! (%s)",strerror(errno));
+ }
/* Have we got a socket and is it nonblocking? */
if (MasterSocket != -1)
{
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));
if (MasterSocket >= 0)
{
+ log(DEBUG,"Add master socket %d",MasterSocket);
/* Hook the descriptor into the socket engine */
if (ServerInstance && ServerInstance->SE)
ServerInstance->SE->AddFd(MasterSocket,true,X_ESTAB_DNS);
DNSRequest* req = this->AddQuery(&h, id);
- if (req->SendRequests(&h, length, DNS_QUERY_A) == -1)
+ if ((!req) || (req->SendRequests(&h, length, DNS_QUERY_A) == -1))
+ return -1;
+
+ return id;
+}
+
+/* Start lookup of an hostname to an IPv6 address */
+int DNS::GetIP6(const char *name)
+{
+ DNSHeader h;
+ int id;
+ int length;
+
+ 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)
{
-#ifdef IPV6
- return -1;
-#else
- char query[29];
+ char query[128];
DNSHeader h;
int id;
int length;
+#ifdef IPV6
+ 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 = this->MakePayload(query, DNS_QUERY_PTR, 1, (unsigned char*)&h.payload)) == -1)
return -1;
DNSRequest* req = this->AddQuery(&h, id);
- if (req->SendRequests(&h, length, DNS_QUERY_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;
+ }
+
+ 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;
+}
+
+void DNS::MakeIP6Int(char* query, const in6_addr *ip)
+{
+#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
}
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(MasterSocket,buffer,sizeof(DNSHeader),0,&from,&x);
- /* Attempt to read a header */
- int length = recv(MasterSocket,buffer,sizeof(DNSHeader),0);
+ if (length < 0)
+ log(DEBUG,"Error in recvfrom()! (%s)",strerror(errno));
/* Did we get the whole header? */
if (length < 12)
+ {
/* Nope - something screwed up. */
+ log(DEBUG,"Whole header not read!");
return std::make_pair(-1,"");
+ }
+
+ /* 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
+
+ /* 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, Config->DNSServer)))
+ {
+ log(DEBUG,"port %d is not 53, or %s is not %s",port_from, ipaddr_from, Config->DNSServer);
+ return std::make_pair(-1,"");
+ }
+ }
/* Put the read header info into a header class */
DNS::FillHeader(&header,buffer,length - 12);
}
else
{
+ char formatted[128];
+
/* Forward lookups come back as binary data. We must format them into ascii */
- if (req->type == DNS_QUERY_A)
+ switch (req->type)
{
- 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
- {
- /* Reverse lookups just come back as char* */
- 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:
+ 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 */
switch (rr.type)
{
+ case DNS_QUERY_CNAME:
+ /* CNAME and PTR have the same processing code */
case DNS_QUERY_PTR:
o = 0;
q = 0;
}
res[o] = 0;
break;
+ case DNS_QUERY_AAAA:
+ memcpy(res,&header.payload[i],rr.rdlength);
+ res[rr.rdlength] = 0;
+ break;
case DNS_QUERY_A:
memcpy(res,&header.payload[i],rr.rdlength);
res[rr.rdlength] = 0;
- break;
+ break;
default:
memcpy(res,&header.payload[i],rr.rdlength);
res[rr.rdlength] = 0;
- break;
+ break;
}
return std::make_pair(res,"No error");;
}
}
/* High level abstraction of dns used by application at large */
-Resolver::Resolver(const std::string &source, bool forward) : input(source), fwd(forward)
+Resolver::Resolver(const std::string &source, QueryType qt) : input(source), querytype(qt)
{
- if (forward)
- {
- log(DEBUG,"Resolver: Forward lookup on %s",source.c_str());
- this->myid = ServerInstance->Res->GetIP(source.c_str());
- }
- else
+ 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 = ServerInstance->Res->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)
{
/* Process a socket read event */
void DNS::MarshallReads(int fd)
{
+ log(DEBUG,"Marshall reads: %d %d",fd,GetMasterSocket());
/* We are only intrested in our single fd */
if (fd == GetMasterSocket())
{
log(DEBUG,"Error available, id=%d",res.first);
if (Classes[res.first])
{
+ if (ServerInstance && ServerInstance->stats)
+ ServerInstance->stats->statsDnsBad++;
Classes[res.first]->OnError(RESOLVER_NXDOMAIN, res.second);
delete Classes[res.first];
Classes[res.first] = NULL;
/* Marshall the result to the correct class */
if (Classes[res.first])
{
+ 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++;
+
}
}
}
}
}
+unsigned long DNS::PRNG()
+{
+ 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;
+}
+
projects / user / henk / code / inspircd.git / blobdiff