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#include "edns0.h"
#include "byte.h"
#include "case.h"
#include "env.h"
#include "buffer.h"
#include "strerr.h"
#include "ip4.h"
#include "ip6.h"
#include "uint16.h"
#include "ndelay.h"
#include "socket.h"
#include "droproot.h"
#include "qlog.h"
#include "response.h"
#include "dns.h"
#include "alloc.h"
#include "iopause.h"
#include "str.h"
extern char *fatal;
extern char *starting;
extern int respond(char *,char *,char *);
extern void initialize(void);
static char ip[16];
static uint16 port;
static char buf[513];
static int len;
static char *q;
void nomem()
{
strerr_die2x(111,fatal,"out of memory");
}
static int doit(void)
{
unsigned int pos;
char header[12];
char qtype[2];
char qclass[2];
if (len >= sizeof buf) goto NOQ;
pos = dns_packet_copy(buf,len,0,header,12); if (!pos) goto NOQ;
if (header[2] & 128) goto NOQ;
if (header[4]) goto NOQ;
if (header[5] != 1) goto NOQ;
pos = dns_packet_getname(buf,len,pos,&q); if (!pos) goto NOQ;
pos = dns_packet_copy(buf,len,pos,qtype,2); if (!pos) goto NOQ;
pos = dns_packet_copy(buf,len,pos,qclass,2); if (!pos) goto NOQ;
if (!response_query(q,qtype,qclass)) goto NOQ;
response_id(header);
if (byte_equal(qclass,2,DNS_C_IN))
response[2] |= 4;
else
if (byte_diff(qclass,2,DNS_C_ANY)) goto WEIRDCLASS;
response[3] &= ~128;
if (!(header[2] & 1)) response[2] &= ~1;
if (header[2] & 126) goto NOTIMP;
if (byte_equal(qtype,2,DNS_T_AXFR)) goto NOTIMP;
pos = check_edns0(header, buf, len, pos);
if (!pos) goto NOQ;
case_lowerb(q,dns_domain_length(q));
if (!respond(q,qtype,ip)) {
qlog(ip,port,header,q,qtype," - ");
return 0;
}
qlog(ip,port,header,q,qtype," + ");
return 1;
NOTIMP:
response[3] &= ~15;
response[3] |= 4;
qlog(ip,port,header,q,qtype," I ");
return 1;
WEIRDCLASS:
response[3] &= ~15;
response[3] |= 1;
qlog(ip,port,header,q,qtype," C ");
return 1;
NOQ:
qlog(ip,port,"\0\0","","\0\0"," / ");
return 0;
}
int main()
{
char *x;
int *udp53;
unsigned int off;
unsigned int cnt;
iopause_fd *iop;
x = env_get("IP");
if (!x)
strerr_die2x(111,fatal,"$IP not set");
off=cnt=0;
while (x[off]) {
unsigned int l;
char dummy[16];
l=ip6_scan(x+off,dummy);
if (!l)
strerr_die3x(111,fatal,"unable to parse IP address ",x+off);
cnt++;
if (!x[off+l]) break;
if (x[off+l]=='%')
while (x[off+l] && x[off+l]!=',') ++l;
if (x[off+l]!=',')
strerr_die3x(111,fatal,"unable to parse IP address ",x+off);
off+=l+1;
}
udp53=(int *) alloc(sizeof(int) *cnt);
if (!udp53) nomem();
iop=(iopause_fd *) alloc(sizeof(*iop) * cnt);
if (!iop) nomem();
off=cnt=0;
while (x[off]) {
unsigned int l;
uint32 ifid=0;
l=ip6_scan(x+off,ip);
udp53[cnt] = socket_udp6();
if (udp53[cnt] == -1)
strerr_die2sys(111,fatal,"unable to create UDP socket: ");
if (x[off+l]=='%') {
char* interface=x+off+l+1;
int Len=str_chr(interface,',');
if (interface[Len]) {
interface[Len]=0;
ifid=socket_getifidx(interface);
interface[Len]=',';
} else
ifid=socket_getifidx(interface);
l+=Len;
}
if (socket_bind6_reuse(udp53[cnt],ip,53,ifid) == -1)
strerr_die2sys(111,fatal,"unable to bind UDP socket: ");
ndelay_off(udp53[cnt]);
socket_tryreservein(udp53[cnt],65536);
iop[cnt].fd=udp53[cnt];
iop[cnt].events=IOPAUSE_READ;
cnt++;
if (!x[off+l]) break;
off+=l+1;
}
droproot(fatal);
initialize();
buffer_putsflush(buffer_2,starting);
for (;;) {
struct taia stamp;
struct taia deadline;
unsigned int i;
uint32 ifid;
taia_now(&stamp);
taia_uint(&deadline,300);
taia_add(&deadline,&deadline,&stamp);
iopause(iop,cnt,&deadline,&stamp);
for (i=0;i<cnt;i++)
if (iop[i].revents) {
len = socket_recv6(udp53[i],buf,sizeof buf,ip,&port,&ifid);
if (len < 0) continue;
if (!doit()) continue;
if (response_len > max_response_len) response_tc();
socket_send6(udp53[i],response,response_len,ip,port,ifid);
/* may block for buffer space; if it fails, too bad */
}
}
}
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