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-rw-r--r--src/dns.cpp284
1 files changed, 172 insertions, 112 deletions
diff --git a/src/dns.cpp b/src/dns.cpp
index 1537f3393..a62027117 100644
--- a/src/dns.cpp
+++ b/src/dns.cpp
@@ -1,22 +1,31 @@
-/*
-dns.cpp - based on the firedns library Copyright (C) 2002 Ian Gulliver
-
-This program is free software; you can redistribute it and/or modify
-it under the terms of version 2 of the GNU General Public License as
-published by the Free Software Foundation.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
+/* +------------------------------------+
+ * | Inspire Internet Relay Chat Daemon |
+ * +------------------------------------+
+ *
+ * Inspire is copyright (C) 2002-2005 ChatSpike-Dev.
+ * E-mail:
+ * <brain@chatspike.net>
+ * <Craig@chatspike.net>
+ *
+ * Written by Craig Edwards, Craig McLure, and others.
+ * This program is free but copyrighted software; see
+ * the file COPYING for details.
+ *
+ * ---------------------------------------------------
+ */
-You should have received a copy of the GNU General Public License
-along with this program; if not, write to the Free Software
-Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+/*
+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
*/
-#define _DNS_C
-
using namespace std;
#include <string>
@@ -95,7 +104,8 @@ class s_header
};
-void *dns_align(void *inp) {
+void *dns_align(void *inp)
+{
char *p = (char*)inp;
int offby = ((char *)p - (char *)0) % (sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long));
if (offby != 0)
@@ -111,14 +121,16 @@ void *dns_align(void *inp) {
* but of course, more impressive). Also made these inline.
*/
-inline void dns_fill_rr(s_rr_middle* rr, const unsigned char *input) {
+inline void dns_fill_rr(s_rr_middle* rr, const unsigned char *input)
+{
rr->type = (QueryType)((input[0] << 8) + input[1]);
rr->_class = (input[2] << 8) + input[3];
rr->ttl = (input[4] << 24) + (input[5] << 16) + (input[6] << 8) + input[7];
rr->rdlength = (input[8] << 8) + input[9];
}
-inline void dns_fill_header(s_header *header, const unsigned char *input, const int l) {
+inline void dns_fill_header(s_header *header, const unsigned char *input, const int l)
+{
header->id[0] = input[0];
header->id[1] = input[1];
header->flags1 = input[2];
@@ -130,7 +142,8 @@ inline void dns_fill_header(s_header *header, const unsigned char *input, const
memcpy(header->payload,&input[12],l);
}
-inline void dns_empty_header(unsigned char *output, const s_header *header, const int l) {
+inline void dns_empty_header(unsigned char *output, const s_header *header, const int l)
+{
output[0] = header->id[0];
output[1] = header->id[1];
output[2] = header->flags1;
@@ -146,12 +159,14 @@ inline void dns_empty_header(unsigned char *output, const s_header *header, cons
memcpy(&output[12],header->payload,l);
}
-void dns_close(int fd) { /* close query */
+void dns_close(int fd)
+{
#ifndef THREADED_DNS
ServerInstance->SE->DelFd(fd);
#endif
log(DEBUG,"DNS: dns_close on fd %d",fd);
- if (fd == lastcreate) {
+ if (fd == lastcreate)
+ {
wantclose = 1;
return;
}
@@ -160,7 +175,8 @@ void dns_close(int fd) { /* close query */
return;
}
-void DNS::dns_init() {
+void DNS::dns_init()
+{
FILE *f;
int i;
in_addr addr4;
@@ -176,11 +192,13 @@ void DNS::dns_init() {
if (f == NULL)
return;
while (fgets(buf,1024,f) != NULL) {
- if (strncmp(buf,"nameserver",10) == 0) {
+ if (strncmp(buf,"nameserver",10) == 0)
+ {
i = 10;
while (buf[i] == ' ' || buf[i] == '\t')
i++;
- if (i4 < 8) {
+ if (i4 < 8)
+ {
if (dns_aton4_s(&buf[i],&addr4) != NULL)
memcpy(&servers4[i4++],&addr4,sizeof(in_addr));
}
@@ -200,7 +218,7 @@ void DNS::dns_init_2(const char* dnsserver)
}
-static int dns_send_requests(const s_header *h, const s_connection *s, const int l)
+int dns_send_requests(const s_header *h, const s_connection *s, const int l)
{
int i;
sockaddr_in addr4;
@@ -224,7 +242,8 @@ static int dns_send_requests(const s_header *h, const s_connection *s, const int
return 0;
}
-static s_connection *dns_add_query(s_header *h) { /* build DNS query, add to list */
+s_connection *dns_add_query(s_header *h)
+{
s_connection * s = new s_connection;
int id = rand() % 65536;
@@ -238,40 +257,42 @@ static s_connection *dns_add_query(s_header *h) { /* build DNS query, add to lis
h->ancount = 0;
h->nscount = 0;
h->arcount = 0;
-
- /* turn off want_list by default */
s->want_list = 0;
-
- /* try to create ipv6 or ipv4 socket */
- s->fd = socket(PF_INET, SOCK_DGRAM, 0);
- if (s->fd != -1) {
- if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0) {
- shutdown(s->fd,2);
- close(s->fd);
- s->fd = -1;
- }
- }
- if (s->fd != -1) {
- sockaddr_in addr;
- memset(&addr,0,sizeof(addr));
- addr.sin_family = AF_INET;
- addr.sin_port = 0;
- addr.sin_addr.s_addr = INADDR_ANY;
- if (bind(s->fd,(sockaddr *)&addr,sizeof(addr)) != 0) {
- shutdown(s->fd,2);
- close(s->fd);
- s->fd = -1;
- }
+ s->fd = socket(PF_INET, SOCK_DGRAM, 0);
+ if (s->fd != -1)
+ {
+ if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0)
+ {
+ shutdown(s->fd,2);
+ close(s->fd);
+ s->fd = -1;
}
- if (s->fd == -1) {
- delete s;
- return NULL;
+ }
+ if (s->fd != -1)
+ {
+ sockaddr_in addr;
+ memset(&addr,0,sizeof(addr));
+ addr.sin_family = AF_INET;
+ addr.sin_port = 0;
+ addr.sin_addr.s_addr = INADDR_ANY;
+ if (bind(s->fd,(sockaddr *)&addr,sizeof(addr)) != 0)
+ {
+ shutdown(s->fd,2);
+ close(s->fd);
+ s->fd = -1;
}
+ }
+ if (s->fd == -1)
+ {
+ delete s;
+ return NULL;
+ }
/* create new connection object, add to linked list */
if (connections.find(s->fd) == connections.end())
connections[s->fd] = s;
- if (wantclose == 1) {
+ if (wantclose == 1)
+ {
shutdown(lastcreate,2);
close(lastcreate);
wantclose = 0;
@@ -280,7 +301,8 @@ static s_connection *dns_add_query(s_header *h) { /* build DNS query, add to lis
return s;
}
-static int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short _class, unsigned char * const payload) {
+int dns_build_query_payload(const char * const name, const unsigned short rr, const unsigned short _class, unsigned char * const payload)
+{
short payloadpos;
const char * tempchr, * tempchr2;
unsigned short l;
@@ -289,7 +311,8 @@ static int dns_build_query_payload(const char * const name, const unsigned short
tempchr2 = name;
/* split name up into labels, create query */
- while ((tempchr = strchr(tempchr2,'.')) != NULL) {
+ while ((tempchr = strchr(tempchr2,'.')) != NULL)
+ {
l = tempchr - tempchr2;
if (payloadpos + l + 1 > 507)
return -1;
@@ -299,7 +322,8 @@ static int dns_build_query_payload(const char * const name, const unsigned short
tempchr2 = &tempchr[1];
}
l = strlen(tempchr2);
- if (l) {
+ if (l)
+ {
if (payloadpos + l + 2 > 507)
return -1;
payload[payloadpos++] = l;
@@ -316,7 +340,8 @@ static int dns_build_query_payload(const char * const name, const unsigned short
return payloadpos + 4;
}
-in_addr* DNS::dns_aton4(const char * const ipstring) { /* ascii to numeric: convert string to static 4part IP addr struct */
+in_addr* DNS::dns_aton4(const char * const ipstring)
+{
static in_addr ip;
return dns_aton4_s(ipstring,&ip);
}
@@ -324,7 +349,8 @@ in_addr* DNS::dns_aton4(const char * const ipstring) { /* ascii to numeric: conv
in_addr* DNS::dns_aton4_r(const char *ipstring) { /* ascii to numeric (reentrant): convert string to new 4part IP addr struct */
in_addr* ip;
ip = new in_addr;
- if(dns_aton4_s(ipstring,ip) == NULL) {
+ if(dns_aton4_s(ipstring,ip) == NULL)
+ {
delete ip;
return NULL;
}
@@ -365,7 +391,6 @@ int DNS::dns_getip4list(const char *name) { /* build, add and send A query; retr
dns_init();
-
l = dns_build_query_payload(name,DNS_QRY_A,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
@@ -451,80 +476,98 @@ char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS
l = recv(c->fd,buffer,sizeof(s_header),0);
dns_close(c->fd);
- if (l < 12) {
+ if (l < 12)
+ {
delete c;
return NULL;
}
dns_fill_header(&h,buffer,l - 12);
- if (c->id[0] != h.id[0] || c->id[1] != h.id[1]) {
+ if (c->id[0] != h.id[0] || c->id[1] != h.id[1])
+ {
log(DEBUG,"DNS: id mismatch on query");
delete c;
return NULL; /* ID mismatch */
}
- if ((h.flags1 & FLAGS1_MASK_QR) == 0) {
+ if ((h.flags1 & FLAGS1_MASK_QR) == 0)
+ {
log(DEBUG,"DNS: didnt get a query result");
delete c;
return NULL;
}
- if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0) {
+ if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0)
+ {
log(DEBUG,"DNS: got an OPCODE and didnt want one");
delete c;
return NULL;
}
- if ((h.flags2 & FLAGS2_MASK_RCODE) != 0) {
+ if ((h.flags2 & FLAGS2_MASK_RCODE) != 0)
+ {
log(DEBUG,"DNS lookup failed due to SERVFAIL");
delete c;
return NULL;
}
- if (h.ancount < 1) { /* no sense going on if we don't have any answers */
+ if (h.ancount < 1)
+ {
log(DEBUG,"DNS: no answers!");
delete c;
return NULL;
}
- /* skip queries */
i = 0;
q = 0;
l -= 12;
- while ((unsigned)q < h.qdcount && i < l) {
- if (h.payload[i] > 63) { /* pointer */
- i += 6; /* skip pointer, _class and type */
+ while ((unsigned)q < h.qdcount && i < l)
+ {
+ if (h.payload[i] > 63)
+ {
+ i += 6;
q++;
- } else { /* label */
- if (h.payload[i] == 0) {
+ }
+ else
+ {
+ if (h.payload[i] == 0)
+ {
q++;
- i += 5; /* skip nil, _class and type */
- } else
- i += h.payload[i] + 1; /* skip length and label */
+ i += 5;
+ }
+ else i += h.payload[i] + 1;
}
}
- /* &h.payload[i] should now be the start of the first response */
curanswer = 0;
- while ((unsigned)curanswer < h.ancount) {
+ while ((unsigned)curanswer < h.ancount)
+ {
q = 0;
- while (q == 0 && i < l) {
- if (h.payload[i] > 63) { /* pointer */
- i += 2; /* skip pointer */
+ while (q == 0 && i < l)
+ {
+ if (h.payload[i] > 63)
+ {
+ i += 2;
q = 1;
- } else { /* label */
- if (h.payload[i] == 0) {
+ }
+ else
+ {
+ if (h.payload[i] == 0)
+ {
i++;
q = 1;
- } else
- i += h.payload[i] + 1; /* skip length and label */
+ }
+ else i += h.payload[i] + 1; /* skip length and label */
}
}
- if (l - i < 10) {
+ if (l - i < 10)
+ {
delete c;
return NULL;
}
dns_fill_rr(&rr,&h.payload[i]);
i += 10;
- if (rr.type != c->type) {
+ if (rr.type != c->type)
+ {
curanswer++;
i += rr.rdlength;
continue;
}
- if (rr._class != c->_class) {
+ if (rr._class != c->_class)
+ {
curanswer++;
i += rr.rdlength;
continue;
@@ -538,19 +581,27 @@ char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS
if (rr.rdlength > 1023)
return NULL;
- switch (rr.type) {
+ switch (rr.type)
+ {
case DNS_QRY_PTR:
log(DEBUG,"DNS: got a result of type DNS_QRY_PTR");
o = 0;
q = 0;
- while (q == 0 && i < l && o + 256 < 1023) {
- if (h.payload[i] > 63) { /* pointer */
+ while (q == 0 && i < l && o + 256 < 1023)
+ {
+ if (h.payload[i] > 63)
+ {
memcpy(&p,&h.payload[i],2);
i = ntohs(p) - 0xC000 - 12;
- } else { /* label */
+ }
+ else
+ {
if (h.payload[i] == 0)
+ {
q = 1;
- else {
+ }
+ else
+ {
res[o] = '\0';
if (o != 0)
res[o++] = '.';
@@ -561,17 +612,20 @@ char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS
}
}
res[o] = '\0';
- break;
+ break;
case DNS_QRY_A:
log(DEBUG,"DNS: got a result of type DNS_QRY_A");
- if (c->want_list) {
+ if (c->want_list)
+ {
dns_ip4list *alist = (dns_ip4list *) res; /* we have to trust that this is aligned */
- while ((char *)alist - (char *)res < 700) {
+ while ((char *)alist - (char *)res < 700)
+ {
if (rr.type != DNS_QRY_A)
break;
if (rr._class != 1)
break;
- if (rr.rdlength != 4) {
+ if (rr.rdlength != 4)
+ {
delete c;
return NULL;
}
@@ -579,23 +633,26 @@ char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS
if ((unsigned)++curanswer >= h.ancount)
break;
i += rr.rdlength;
+ q = 0;
+ while (q == 0 && i < l)
{
- /* skip next name */
- q = 0;
- while (q == 0 && i < l) {
- if (h.payload[i] > 63) { /* pointer */
- i += 2; /* skip pointer */
+ if (h.payload[i] > 63)
+ {
+ i += 2;
+ q = 1;
+ }
+ else
+ {
+ if (h.payload[i] == 0)
+ {
+ i++;
q = 1;
- } else { /* label */
- if (h.payload[i] == 0) {
- i++;
- q = 1;
- } else
- i += h.payload[i] + 1; /* skip length and label */
}
+ else i += h.payload[i] + 1;
}
}
- if (l - i < 10) {
+ if (l - i < 10)
+ {
delete c;
return NULL;
}
@@ -612,7 +669,6 @@ char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS
break;
default:
defaultcase:
- log(DEBUG,"DNS: doing something with result 'default'");
memcpy(res,&h.payload[i],rr.rdlength);
res[rr.rdlength] = '\0';
break;
@@ -647,7 +703,8 @@ bool DNS::ReverseLookup(std::string ip)
{
ServerInstance->stats->statsDns++;
binip = dns_aton4(ip.c_str());
- if (binip == NULL) {
+ if (binip == NULL)
+ {
return false;
}
@@ -707,11 +764,14 @@ std::string DNS::GetResult()
{
log(DEBUG,"DNS: GetResult()");
result = dns_getresult(this->myfd);
- if (result) {
+ if (result)
+ {
ServerInstance->stats->statsDnsGood++;
dns_close(this->myfd);
return result;
- } else {
+ }
+ else
+ {
ServerInstance->stats->statsDnsBad++;
if (this->myfd != -1)
{
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 16:34:54 +0000