X-Git-Url: https://git.netwichtig.de/gitweb/?a=blobdiff_plain;f=src%2Fdns.cpp;h=123901f8ace3e09f621c590876495c189ddd48fc;hb=3d7cec97446cf3b7f7c6b5d1dce7f065353a593b;hp=1537f339354227f828770bdfa5cb4a601c86362d;hpb=fb135c90caa3ddd0606e8913f69259b482c758a3;p=user%2Fhenk%2Fcode%2Finspircd.git diff --git a/src/dns.cpp b/src/dns.cpp index 1537f3393..123901f8a 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 | + * +------------------------------------+ + * + * InspIRCd is copyright (C) 2002-2006 ChatSpike-Dev. + * E-mail: + * + * + * + * 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 @@ -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; } @@ -608,11 +665,11 @@ char* DNS::dns_getresult_s(const int cfd, char *res) { /* retrieve result of DNS alist->next = NULL; break; } - goto defaultcase; + memcpy(res,&h.payload[i],rr.rdlength); + res[rr.rdlength] = '\0'; 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 +704,8 @@ 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 +765,14 @@ 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) {