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firedns.c
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firedns.c
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/*
firedns.c - 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.
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
*/
#define _FIREDNS_C
#include <stdlib.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
//#include <pthread.h>
#include "firestring.h"
#include "firemake.h"
#include "firedns.h"
static const char tagstring[] = "$Id: firedns.c,v 1.81 2004/03/10 15:14:35 ian Exp $";
const char firedns_version[] = "1.9.9";
/* MXPS protocol default ports */
const int firedns_mx_port[] = { 25, 209, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0,
0, 0, 0, 0 };
const char *firedns_mx_name[] = { "SMTP", "QMTP", "Unknown", "Unknown",
"Unknown", "Unknown", "Unknown", "Unknown",
"Unknown", "Unknown", "Unknown", "Unknown",
"Unknown", "Unknown", "Unknown", "Unknown" };
#define max(a,b) (a > b ? a : b)
#define FDNS_MAX 8 /* max number of nameservers used */
#define FDNS_CONFIG_PREF "/etc/firedns.conf" /* preferred firedns config file */
#define FDNS_CONFIG_FBCK "/etc/resolv.conf" /* fallback config file */
#define FDNS_PORT 53 /* DNS well known port */
#define FDNS_QRY_A 1 /* name to IP address */
#define FDNS_QRY_AAAA 28 /* name to IP6 address */
#define FDNS_QRY_PTR 12 /* IP address to name */
#define FDNS_QRY_MX 15 /* name to MX */
#define FDNS_QRY_TXT 16 /* name to TXT */
#define FDNS_QRY_CNAME 5
#define FDNS_MXPS_START 12800
#define FDNS_MXPS_STOP 13055
#define FIREDNS_ALIGN (sizeof(void *) > sizeof(long) ? sizeof(void *) : sizeof(long))
#define FIREDNS_TRIES 3
#define RESULTSIZE 1024
#define min(a,b) (a < b ? a : b)
static struct in_addr servers4[FDNS_MAX]; /* up to FDNS_MAX nameservers; populated by firedns_init() */
static int i4; /* actual count of nameservers; set by firedns_init() */
#ifdef HAVE_IPV6
static int i6;
static struct in6_addr servers6[FDNS_MAX];
#endif
static int initdone = 0; /* to ensure firedns_init() only runs once (on the first call) */
static int wantclose = 0;
static int lastcreate = -1;
struct s_connection { /* open DNS query */
struct s_connection *next; /* next in list */
unsigned char id[2]; /* unique ID (random number), matches header ID; both set by firedns_add_query() */
unsigned int class_;
unsigned int type;
int want_list;
int fd; /* file descriptor returned from sockets */
#ifdef HAVE_IPV6
int v6;
#endif
};
struct s_rr_middle {
unsigned int type;
unsigned int class_;
unsigned long ttl;
unsigned int rdlength;
};
#define FIREDNS_POINTER_VALUE 0xc000
//static pthread_mutex_t connlist_lock = PTHREAD_MUTEX_INITIALIZER;
static struct s_connection *connection_head = NULL; /* linked list of open DNS queries; populated by firedns_add_query(), decimated by firedns_getresult_s() */
struct s_header { /* DNS query header */
unsigned char id[2];
unsigned int flags1;
#define FLAGS1_MASK_QR 0x80
#define FLAGS1_MASK_OPCODE 0x78 /* bitshift right 3 */
#define FLAGS1_MASK_AA 0x04
#define FLAGS1_MASK_TC 0x02
#define FLAGS1_MASK_RD 0x01
unsigned int flags2;
#define FLAGS2_MASK_RA 0x80
#define FLAGS2_MASK_Z 0x70
#define FLAGS2_MASK_RCODE 0x0f
unsigned int qdcount;
unsigned int ancount;
unsigned int nscount;
unsigned int arcount;
unsigned char payload[512]; /* DNS question, populated by firedns_build_query_payload() */
};
static void *firedns_align(void *inp) {
char *p = (char *) inp;
int offby = ((char *)p - (char *)0) % FIREDNS_ALIGN;
if (offby != 0)
return p + (FIREDNS_ALIGN - offby);
else
return p;
}
/*
* These little hacks are here to avoid alignment and type sizing issues completely by doing manual copies
*/
static void firedns_fill_rr(struct s_rr_middle *const rr, const unsigned char *input) {
rr->type = input[0] * 256 + input[1];
rr->class_ = input[2] * 256 + input[3];
rr->ttl = input[4] * 16777216 + input[5] * 65536 + input[6] * 256 + input[7];
rr->rdlength = input[8] * 256 + input[9];
}
static void firedns_fill_header(struct s_header *header, const unsigned char *input, const int l) {
header->id[0] = input[0];
header->id[1] = input[1];
header->flags1 = input[2];
header->flags2 = input[3];
header->qdcount = input[4] * 256 + input[5];
header->ancount = input[6] * 256 + input[7];
header->nscount = input[8] * 256 + input[9];
header->arcount = input[10] * 256 + input[11];
memcpy(header->payload,&input[12],l);
}
static void firedns_empty_header(unsigned char *output, const struct s_header *header, const int l) {
output[0] = header->id[0];
output[1] = header->id[1];
output[2] = header->flags1;
output[3] = header->flags2;
output[4] = header->qdcount / 256;
output[5] = header->qdcount % 256;
output[6] = header->ancount / 256;
output[7] = header->ancount % 256;
output[8] = header->nscount / 256;
output[9] = header->nscount % 256;
output[10] = header->arcount / 256;
output[11] = header->arcount % 256;
memcpy(&output[12],header->payload,l);
}
static void firedns_close(int fd) { /* close query */
if (fd == lastcreate) {
wantclose = 1;
return;
}
close(fd);
return;
}
void firedns_init() { /* on first call only: populates servers4 (or -6) struct with up to FDNS_MAX nameserver IP addresses from /etc/firedns.conf (or /etc/resolv.conf) */
FILE *f;
int i;
struct in_addr addr4;
char buf[1024];
#ifdef HAVE_IPV6
struct in6_addr addr6;
#endif
if (initdone == 1)
return;
#ifdef HAVE_IPV6
i6 = 0;
#endif
i4 = 0;
initdone = 1;
srand((unsigned int) time(NULL));
memset(servers4,'\0',sizeof(struct in_addr) * FDNS_MAX);
#ifdef HAVE_IPV6
memset(servers6,'\0',sizeof(struct in6_addr) * FDNS_MAX);
#endif
/* read /etc/firedns.conf if we've got it, otherwise parse /etc/resolv.conf */
f = fopen(FDNS_CONFIG_PREF,"r");
if (f == NULL) {
f = fopen(FDNS_CONFIG_FBCK,"r");
if (f == NULL)
return;
while (fgets(buf,1024,f) != NULL) {
if (strncmp(buf,"nameserver",10) == 0) {
i = 10;
while (buf[i] == ' ' || buf[i] == '\t')
i++;
#ifdef HAVE_IPV6
/* glibc /etc/resolv.conf seems to allow ipv6 server names */
if (i6 < FDNS_MAX) {
if (firedns_aton6_s(&buf[i],&addr6) != NULL) {
memcpy(&servers6[i6++],&addr6,sizeof(struct in6_addr));
continue;
}
}
#endif
if (i4 < FDNS_MAX) {
if (firedns_aton4_s(&buf[i],&addr4) != NULL)
memcpy(&servers4[i4++],&addr4,sizeof(struct in_addr));
}
}
}
} else {
while (fgets(buf,1024,f) != NULL) {
#ifdef HAVE_IPV6
if (i6 < FDNS_MAX) {
if (firedns_aton6_s(buf,&addr6) != NULL) {
memcpy(&servers6[i6++],&addr6,sizeof(struct in6_addr));
continue;
}
}
#endif
if (i4 < FDNS_MAX) {
if (firedns_aton4_s(buf,&addr4) != NULL)
memcpy(&servers4[i4++],&addr4,sizeof(struct in_addr));
}
}
}
fclose(f);
}
static int firedns_send_requests(const struct s_header *h, const struct s_connection *s, const int l) { /* send DNS query */
int i;
struct sockaddr_in addr4;
unsigned char payload[sizeof(struct s_header)];
#ifdef HAVE_IPV6
struct sockaddr_in6 addr6;
#endif
firedns_empty_header(payload,h,l);
#ifdef HAVE_IPV6
/* if we've got ipv6 support, an ip v6 socket, and ipv6 servers, send to them */
if (i6 > 0 && s->v6 == 1) {
for (i = 0; i < i6; i++) {
memset(&addr6,0,sizeof(addr6));
memcpy(&addr6.sin6_addr,&servers6[i],sizeof(addr6.sin6_addr));
addr6.sin6_family = AF_INET6;
addr6.sin6_port = htons(FDNS_PORT);
sendto(s->fd, payload, l + 12, 0, (struct sockaddr *) &addr6, sizeof(addr6));
}
}
#endif
for (i = 0; i < i4; i++) {
#ifdef HAVE_IPV6
/* send via ipv4-over-ipv6 if we've got an ipv6 socket */
if (s->v6 == 1) {
memset(&addr6,0,sizeof(addr6));
memcpy(addr6.sin6_addr.s6_addr,"\0\0\0\0\0\0\0\0\0\0\xff\xff",12);
memcpy(&addr6.sin6_addr.s6_addr[12],&servers4[i].s_addr,4);
addr6.sin6_family = AF_INET6;
addr6.sin6_port = htons(FDNS_PORT);
sendto(s->fd, payload, l + 12, 0, (struct sockaddr *) &addr6, sizeof(addr6));
continue;
}
#endif
/* otherwise send via standard ipv4 boringness */
memset(&addr4,0,sizeof(addr4));
memcpy(&addr4.sin_addr,&servers4[i],sizeof(addr4.sin_addr));
addr4.sin_family = AF_INET;
addr4.sin_port = htons(FDNS_PORT);
sendto(s->fd, payload, l + 12, 0, (struct sockaddr *) &addr4, sizeof(addr4));
}
return 0;
}
static struct s_connection *firedns_add_query(struct s_header *h) { /* build DNS query, add to list */
struct s_connection *s;
s = (struct s_connection *) firestring_malloc(sizeof(struct s_connection));
/* set header flags */
h->id[0] = s->id[0] = rand() % 255; /* verified by firedns_getresult_s() */
h->id[1] = s->id[1] = rand() % 255;
h->flags1 = 0 | FLAGS1_MASK_RD;
h->flags2 = 0;
h->qdcount = 1;
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 */
#ifdef HAVE_IPV6
s->v6 = 0;
if (i6 > 0) {
s->fd = socket(PF_INET6, SOCK_DGRAM, 0);
if (s->fd != -1) {
if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0) {
close(s->fd);
s->fd = -1;
}
}
if (s->fd != -1) {
struct sockaddr_in6 addr6;
memset(&addr6,0,sizeof(addr6));
addr6.sin6_family = AF_INET6;
if (bind(s->fd,(struct sockaddr *)&addr6,sizeof(addr6)) == 0)
s->v6 = 1;
else
close(s->fd);
}
}
if (s->v6 == 0) {
#endif
s->fd = socket(PF_INET, SOCK_DGRAM, 0);
if (s->fd != -1) {
if (fcntl(s->fd, F_SETFL, O_NONBLOCK) != 0) {
close(s->fd);
s->fd = -1;
}
}
if (s->fd != -1) {
struct 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,(struct sockaddr *)&addr,sizeof(addr)) != 0) {
close(s->fd);
s->fd = -1;
}
}
if (s->fd == -1) {
free(s);
return NULL;
}
#ifdef HAVE_IPV6
}
#endif
/* create new connection object, add to linked list */
//pthread_mutex_lock(&connlist_lock);
s->next = connection_head;
connection_head = s;
if (wantclose == 1) {
close(lastcreate);
wantclose = 0;
}
lastcreate = s->fd;
//pthread_mutex_unlock(&connlist_lock);
return s;
}
static int firedns_build_query_payload(const char *name, const unsigned short rr, const unsigned short class_, unsigned char *payload) { /* populate payload with query: name= question, rr= record type */
short payloadpos;
const char * tempchr, * tempchr2;
unsigned short l;
payloadpos = 0;
tempchr2 = name;
/* split name up into labels, create query */
while ((tempchr = strchr(tempchr2,'.')) != NULL) {
l = tempchr - tempchr2;
if (payloadpos + l + 1 > 507)
return -1;
payload[payloadpos++] = l;
memcpy(&payload[payloadpos],tempchr2,l);
payloadpos += l;
tempchr2 = &tempchr[1];
}
l = strlen(tempchr2);
if (l) {
if (payloadpos + l + 2 > 507)
return -1;
payload[payloadpos++] = l;
memcpy(&payload[payloadpos],tempchr2,l);
payloadpos += l;
payload[payloadpos++] = '\0';
}
if (payloadpos > 508)
return -1;
l = htons(rr);
memcpy(&payload[payloadpos],&l,2);
l = htons(class_);
memcpy(&payload[payloadpos + 2],&l,2);
return payloadpos + 4;
}
struct in_addr *firedns_aton4(const char *ipstring) { /* ascii to numeric: convert string to static 4part IP addr struct */
static struct in_addr ip;
return firedns_aton4_s(ipstring,&ip);
}
struct in_addr *firedns_aton4_r(const char *ipstring) { /* ascii to numeric (reentrant): convert string to new 4part IP addr struct */
struct in_addr *ip;
ip = (struct in_addr *) firestring_malloc(sizeof(struct in_addr));
if(firedns_aton4_s(ipstring,ip) == NULL) {
free(ip);
return NULL;
}
return ip;
}
struct in_addr *firedns_aton4_s(const char *ipstring, struct in_addr *ip) { /* ascii to numeric (buffered): convert string to given 4part IP addr struct */
unsigned char *myip;
int i,part = 0;
myip = (unsigned char *)ip;
memset(myip,'\0',4);
for (i = 0; i < 16; i++) {
switch (ipstring[i]) {
case '\0':
if (part != 3)
return NULL;
return ip;
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
if (myip[part] > 25)
return NULL;
myip[part] *= 10;
if (myip[part] == 250 && ipstring[i] - '0' > 6)
return NULL;
myip[part] += ipstring[i] - '0';
break;
case '.':
if (part == 3)
return ip;
else
part++;
break;
default:
if (part == 3)
return ip;
else
return NULL;
break;
}
}
if (part == 3)
return ip;
else
return NULL;
}
struct in6_addr *firedns_aton6(const char *ipstring) {
static struct in6_addr ip;
return firedns_aton6_s(ipstring,&ip);
}
struct in6_addr *firedns_aton6_r(const char *ipstring) {
struct in6_addr *ip;
ip = (struct in6_addr *) firestring_malloc(sizeof(struct in6_addr));
if(firedns_aton6_s(ipstring,ip) == NULL) {
free(ip);
return NULL;
}
return ip;
}
struct in6_addr *firedns_aton6_s(const char *ipstring, struct in6_addr *ip) {
/* black magic */
char instring[40];
char tempstr[5];
int i,o;
int direction = 1;
char *tempchr,*tempchr2;;
i = strlen(ipstring);
if (i > 39)
return NULL;
memcpy(instring,ipstring,i+1);
memset(ip->s6_addr,'\0',16);
tempchr2 = instring;
i = 0;
while (direction > 0) {
if (direction == 1) {
tempchr = strchr(tempchr2,':');
if (tempchr == NULL && i != 14)
return NULL;
if (tempchr != NULL)
tempchr[0] = '\0';
o = strlen(tempchr2);
if (o > 4)
return NULL;
strcpy(tempstr,"0000");
strcpy(&tempstr[4 - o],tempchr2);
o = firestring_hextoi(tempstr);
if (o == -1)
return NULL;
ip->s6_addr[i++] = o;
o = firestring_hextoi(&tempstr[2]);
if (o == -1)
return NULL;
ip->s6_addr[i++] = o;
if (i >= 15)
break;
tempchr2 = tempchr + 1;
if (tempchr2[0] == ':') {
tempchr2++;
direction = 2;
i = 15;
continue;
}
}
if (direction == 2) {
tempchr = strrchr(tempchr2,':');
if (tempchr == NULL)
tempchr = tempchr2;
else {
tempchr[0] = '\0';
tempchr++;
}
o = strlen(tempchr);
if (o > 4)
return NULL;
strcpy(tempstr,"0000");
strcpy(&tempstr[4 - o],tempchr);
o = firestring_hextoi(&tempstr[2]);
if (o == -1)
return NULL;
ip->s6_addr[i--] = o;
o = firestring_hextoi(tempstr);
if (o == -1)
return NULL;
ip->s6_addr[i--] = o;
if (i <= 1)
break;
if (tempchr == tempchr2)
break;
}
}
return ip;
}
int firedns_getip4(const char *name) { /* build, add and send A query; retrieve result with firedns_getresult() */
struct s_header h;
struct s_connection *s;
int l;
firedns_init();
l = firedns_build_query_payload(name,FDNS_QRY_A,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->type = FDNS_QRY_A;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_getip4list(const char *const name) { /* build, add and send A query; retrieve result with firedns_getresult() */
struct s_header h;
struct s_connection *s;
int l;
firedns_init();
l = firedns_build_query_payload(name,FDNS_QRY_A,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->type = FDNS_QRY_A;
s->want_list = 1;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_getip6(const char *const name) {
struct s_header h;
struct s_connection *s;
int l;
firedns_init();
l = firedns_build_query_payload(name,FDNS_QRY_AAAA,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->type = FDNS_QRY_AAAA;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_getip6list(const char *const name) {
struct s_header h;
struct s_connection *s;
int l;
firedns_init();
l = firedns_build_query_payload(name,FDNS_QRY_AAAA,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->want_list = 1;
s->type = FDNS_QRY_AAAA;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_gettxt(const char *const name) { /* build, add and send TXT query; retrieve result with firedns_getresult() */
struct s_header h;
struct s_connection *s;
int l;
firedns_init();
l = firedns_build_query_payload(name,FDNS_QRY_TXT,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->type = FDNS_QRY_TXT;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_gettxtlist(const char *const name) { /* build, add and send TXT query; retrieve result with firedns_getresult() */
struct s_header h;
struct s_connection *s;
int l;
firedns_init();
l = firedns_build_query_payload(name,FDNS_QRY_TXT,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->want_list = 1;
s->type = FDNS_QRY_TXT;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_getmx(const char *const name) { /* build, add and send MX query; retrieve result with firedns_getresult() */
struct s_header h;
struct s_connection *s;
int l;
firedns_init();
l = firedns_build_query_payload(name,FDNS_QRY_MX,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->type = FDNS_QRY_MX;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_getmxlist(const char *name) {
struct s_header h;
struct s_connection *s;
int l;
firedns_init();
l = firedns_build_query_payload(name,FDNS_QRY_MX,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->type = FDNS_QRY_MX;
s->want_list = 1;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_getname4(const struct in_addr *const ip) { /* build, add and send PTR query; retrieve result with firedns_getresult() */
char query[512];
struct s_header h;
struct s_connection *s;
unsigned char *c;
int l;
firedns_init();
c = (unsigned char *)&ip->s_addr;
sprintf(query,"%d.%d.%d.%d.in-addr.arpa",c[3],c[2],c[1],c[0]);
l = firedns_build_query_payload(query,FDNS_QRY_PTR,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->type = FDNS_QRY_PTR;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_getname6(const struct in6_addr *const ip) {
char query[512];
struct s_header h;
struct s_connection *s;
int l;
firedns_init();
sprintf(query,"%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.%0x.ip6.int",
ip->s6_addr[15] & 0x0f,
(ip->s6_addr[15] & 0xf0) >> 4,
ip->s6_addr[14] & 0x0f,
(ip->s6_addr[14] & 0xf0) >> 4,
ip->s6_addr[13] & 0x0f,
(ip->s6_addr[13] & 0xf0) >> 4,
ip->s6_addr[12] & 0x0f,
(ip->s6_addr[12] & 0xf0) >> 4,
ip->s6_addr[11] & 0x0f,
(ip->s6_addr[11] & 0xf0) >> 4,
ip->s6_addr[10] & 0x0f,
(ip->s6_addr[10] & 0xf0) >> 4,
ip->s6_addr[9] & 0x0f,
(ip->s6_addr[9] & 0xf0) >> 4,
ip->s6_addr[8] & 0x0f,
(ip->s6_addr[8] & 0xf0) >> 4,
ip->s6_addr[7] & 0x0f,
(ip->s6_addr[7] & 0xf0) >> 4,
ip->s6_addr[6] & 0x0f,
(ip->s6_addr[6] & 0xf0) >> 4,
ip->s6_addr[5] & 0x0f,
(ip->s6_addr[5] & 0xf0) >> 4,
ip->s6_addr[4] & 0x0f,
(ip->s6_addr[4] & 0xf0) >> 4,
ip->s6_addr[3] & 0x0f,
(ip->s6_addr[3] & 0xf0) >> 4,
ip->s6_addr[2] & 0x0f,
(ip->s6_addr[2] & 0xf0) >> 4,
ip->s6_addr[1] & 0x0f,
(ip->s6_addr[1] & 0xf0) >> 4,
ip->s6_addr[0] & 0x0f,
(ip->s6_addr[0] & 0xf0) >> 4
);
l = firedns_build_query_payload(query,FDNS_QRY_PTR,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = (struct s_connection *) firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->type = FDNS_QRY_PTR;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_getcname(const char *const name) {
struct s_header h;
struct s_connection *s;
int l;
firedns_init();
l = firedns_build_query_payload(name,FDNS_QRY_CNAME,1,(unsigned char *)&h.payload);
if (l == -1)
return -1;
s = (struct s_connection *) firedns_add_query(&h);
if (s == NULL)
return -1;
s->class_ = 1;
s->type = FDNS_QRY_CNAME;
if (firedns_send_requests(&h,s,l) == -1)
return -1;
return s->fd;
}
int firedns_dnsbl_lookup_a(const struct in_addr *const ip, const char *const name) { /* build, add and send A query to given DNSBL list; retrieve result with firedns_getresult() */
char hostname[256];
firestring_snprintf(hostname,256,"%u.%u.%u.%u.%s",(unsigned int) ((unsigned char *)&ip->s_addr)[3],(unsigned int) ((unsigned char *)&ip->s_addr)[2],(unsigned int) ((unsigned char *)&ip->s_addr)[1],(unsigned int) ((unsigned char *)&ip->s_addr)[0],name);
return firedns_getip4(hostname);
}
int firedns_dnsbl_lookup_txt(const struct in_addr *const ip, const char *const name) { /* build, add and send TXT query to given DNSBL list; retrieve result with firedns_getresult() */
char hostname[256];
firestring_snprintf(hostname,256,"%u.%u.%u.%u.%s",(unsigned int) ((unsigned char *)&ip->s_addr)[3],(unsigned int) ((unsigned char *)&ip->s_addr)[2],(unsigned int) ((unsigned char *)&ip->s_addr)[1],(unsigned int) ((unsigned char *)&ip->s_addr)[0],name);
return firedns_gettxt(hostname);
}
char *firedns_ntoa4(const struct in_addr *ip) { /* numeric to ascii: convert 4part IP addr struct to static string */
static char result[256];
return firedns_ntoa4_s(ip,result);
}
char *firedns_ntoa4_r(const struct in_addr *const ip) { /* numeric to ascii (reentrant): convert 4part IP addr struct to new string */
char *result;
result = (char *) firestring_malloc(256);
return firedns_ntoa4_s(ip,result);
}
char *firedns_ntoa4_s(const struct in_addr *const ip, char *const result) { /* numeric to ascii (buffered): convert 4part IP addr struct to given string */
unsigned char *m;
m = (unsigned char *)&ip->s_addr;
sprintf(result,"%d.%d.%d.%d",m[0],m[1],m[2],m[3]);
return result;
}
char *firedns_ntoa6(const struct in6_addr *ip) {
static char result[256];
return firedns_ntoa6_s(ip,result);
}
char *firedns_ntoa6_r(const struct in6_addr *ip) {
char *result;
result = (char *) firestring_malloc(256);
return firedns_ntoa6_s(ip,result);
}
char *firedns_ntoa6_s(const struct in6_addr *const ip, char *const result) {
char *c;
sprintf(result,"%x:%x:%x:%x:%x:%x:%x:%x",
ntohs(*((unsigned short *)&ip->s6_addr[0])),
ntohs(*((unsigned short *)&ip->s6_addr[2])),
ntohs(*((unsigned short *)&ip->s6_addr[4])),
ntohs(*((unsigned short *)&ip->s6_addr[6])),
ntohs(*((unsigned short *)&ip->s6_addr[8])),
ntohs(*((unsigned short *)&ip->s6_addr[10])),
ntohs(*((unsigned short *)&ip->s6_addr[12])),
ntohs(*((unsigned short *)&ip->s6_addr[14])));
c = strstr(result,":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(result,"0::",3) == 0)
memmove(result,result + 1, strlen(result + 1) + 1);
}
return result;
}
char *firedns_getresult(const int fd) { /* retrieve result of DNS query */
static char result[RESULTSIZE];
return firedns_getresult_s(fd,result);
}
char *firedns_getresult_r(const int fd) { /* retrieve result of DNS query (reentrant) */
char *result;
result = (char *) firestring_malloc(RESULTSIZE);
if(firedns_getresult_s(fd,result) == NULL) {
free(result);
return NULL;
}
return result;
}
char *firedns_getresult_s(const int fd, char *const result) { /* retrieve result of DNS query (buffered) */
struct s_header h;
struct s_connection *c, *prev;
int l,i,q,curanswer,o;
struct s_rr_middle rr;
unsigned char buffer[sizeof(struct s_header)];
unsigned short p;
prev = NULL;
//pthread_mutex_lock(&connlist_lock);
c = connection_head;
while (c != NULL) { /* find query in list of open queries */
if (c->fd == fd)
break;
prev = c;
c = c->next;
}
if (c == NULL) {
//pthread_mutex_unlock(&connlist_lock);
return NULL; /* query not found */
}
/* query found-- pull from list: */
if (prev != NULL)
prev->next = c->next;
else
connection_head = c->next;
//pthread_mutex_unlock(&connlist_lock);
l = recv(c->fd,buffer,sizeof(struct s_header),0);
firedns_close(c->fd);
if (l < 12) {
free(c);
return NULL;
}
firedns_fill_header(&h,buffer,l - 12);
if (c->id[0] != h.id[0] || c->id[1] != h.id[1]) {
free(c);
return NULL; /* ID mismatch */
}
if ((h.flags1 & FLAGS1_MASK_QR) == 0) {
free(c);
return NULL;
}
if ((h.flags1 & FLAGS1_MASK_OPCODE) != 0) {
free(c);
return NULL;
}
if ((h.flags2 & FLAGS2_MASK_RCODE) != 0) {
free(c);
return NULL;
}
if (h.ancount < 1) { /* no sense going on if we don't have any answers */
free(c);
return NULL;
}
/* skip queries */
i = 0;
q = 0;
l -= 12;
while (q < (signed) h.qdcount && i < l) {
if (h.payload[i] > 63) { /* pointer */
i += 6; /* skip pointer, class_ and type */
q++;
} else { /* label */
if (h.payload[i] == 0) {
q++;
i += 5; /* skip nil, class_ and type */
} else
i += h.payload[i] + 1; /* skip length and label */
}
}
/* &h.payload[i] should now be the start of the first response */
curanswer = 0;