int response_addname(char *d)
{
unsigned int dlen;
unsigned int i;
char buf[2];
dlen = dns_domain_length(d);
while (*d) {
for (i = 0;i < name_num;++i)
if (dns_domain_equal(d,name[i])) {
uint16_pack_big(buf,49152 + name_ptr[i]);
return response_addbytes(buf,2);
}
if (dlen <= 128)
if (name_num < NAMES) {
byte_copy(name[name_num],dlen,d);
name_ptr[name_num] = response_len;
++name_num;
}
i = (unsigned char) *d;
++i;
if (!response_addbytes(d,i)) return 0;
d += i;
dlen -= i;
}
return response_addbytes(d,1);
}
int response_rstart(char *d,char type[2],char ttl[4])
{
if (!response_addname(d)) return 0;
if (!response_addbytes(type,2)) return 0;
if (!response_addbytes(DNS_C_IN,2)) return 0;
if (!response_addbytes(ttl,4)) return 0;
if (!response_addbytes("\0\0",2)) return 0;
dpos = response_len;
return 1;
}
int response_query(char *q,char qtype[2])
{
response_len = 0;
name_num = 0;
if (!response_addbytes("\0\0\201\200\0\1\0\0\0\0\0\0",12)) return 0;
if (!response_addname(q)) return 0;
if (!response_addbytes(qtype,2)) return 0;
if (!response_addbytes(DNS_C_IN,2)) return 0;
tctarget = response_len;
return 1;
}
int response_rstart(const char *d,const char type[2],uint32 ttl)
{
char ttlstr[4];
if (!response_addname(d)) return 0;
if (!response_addbytes(type,2)) return 0;
if (!response_addbytes(DNS_C_IN,2)) return 0;
if (flaghidettl) ttl = 0;
uint32_pack_big(ttlstr,ttl);
if (!response_addbytes(ttlstr,4)) return 0;
if (!response_addbytes("\0\0",2)) return 0;
dpos = response_len;
return 1;
}
static int doit(char *q,char qtype[2],char ip[4])
{
int r;
uint32 dlen;
unsigned int qlen;
qlen = dns_domain_length(q);
if (qlen > 255) return 0; /* impossible */
if (byte_diff(qtype,2,DNS_T_A) && byte_diff(qtype,2,DNS_T_ANY)) goto REFUSE;
key[0] = '%';
byte_copy(key + 1,4,ip);
r = cdb_find(&c,key,5);
if (!r) r = cdb_find(&c,key,4);
if (!r) r = cdb_find(&c,key,3);
if (!r) r = cdb_find(&c,key,2);
if (r == -1) return 0;
key[0] = '+';
byte_zero(key + 1,2);
if (r && (cdb_datalen(&c) == 2))
if (cdb_read(&c,key + 1,2,cdb_datapos(&c)) == -1) return 0;
byte_copy(key + 3,qlen,q);
case_lowerb(key + 3,qlen + 3);
r = cdb_find(&c,key,qlen + 3);
if (!r) {
byte_zero(key + 1,2);
r = cdb_find(&c,key,qlen + 3);
}
if (!r) goto REFUSE;
if (r == -1) return 0;
dlen = cdb_datalen(&c);
if (dlen > 512) dlen = 512;
if (cdb_read(&c,data,dlen,cdb_datapos(&c)) == -1) return 0;
dns_sortip(data,dlen);
if (dlen > 12) dlen = 12;
while (dlen >= 4) {
dlen -= 4;
if (!response_rstart(q,DNS_T_A,"\0\0\0\5")) return 0;
if (!response_addbytes(data + dlen,4)) return 0;
response_rfinish(RESPONSE_ANSWER);
}
return 1;
REFUSE:
response[2] &= ~4;
response[3] &= ~15;
response[3] |= 5;
return 1;
}
static int dobytes(unsigned int len)
{
char buf[20];
if (len > 20) return 0;
dpos = dns_packet_copy(data,dlen,dpos,buf,len);
if (!dpos) return 0;
return response_addbytes(buf,len);
}
int
response_query (const char *q, const char qtype[2], const char qclass[2])
{
response_len = name_num = 0;
if (!response_addbytes ("\0\0\201\200\0\1\0\0\0\0\0\0", 12))
return 0;
if (!response_addname (q))
return 0;
if (!response_addbytes (qtype, 2))
return 0;
if (!response_addbytes (qclass, 2))
return 0;
tctarget = response_len;
return 1;
}
static int doit(char *q,char qtype[2])
{
unsigned int bpos;
unsigned int anpos;
unsigned int aupos;
unsigned int arpos;
char *control;
char *wild;
int flaggavesoa;
int flagfound;
int r;
int flagns;
int flagauthoritative;
char x[20];
uint16 u16;
char addr[8][4];
int addrnum;
uint32 addrttl;
int i;
anpos = response_len;
control = q;
for (;;) {
flagns = 0;
flagauthoritative = 0;
cdb_findstart(&c);
while (r = find(control,0)) {
if (r == -1) return 0;
if (byte_equal(type,2,DNS_T_SOA)) flagauthoritative = 1;
if (byte_equal(type,2,DNS_T_NS)) flagns = 1;
}
if (flagns) break;
if (!*control) return 0; /* q is not within our bailiwick */
control += *control;
control += 1;
}
if (!flagauthoritative) {
response[2] &= ~4;
goto AUTHORITY; /* q is in a child zone */
}
flaggavesoa = 0;
flagfound = 0;
wild = q;
for (;;) {
addrnum = 0;
addrttl = 0;
cdb_findstart(&c);
while (r = find(wild,wild != q)) {
if (r == -1) return 0;
flagfound = 1;
if (flaggavesoa && byte_equal(type,2,DNS_T_SOA)) continue;
if (byte_diff(type,2,qtype) && byte_diff(qtype,2,DNS_T_ANY) && byte_diff(type,2,DNS_T_CNAME)) continue;
if (byte_equal(type,2,DNS_T_A) && (dlen - dpos == 4)) {
addrttl = ttl;
i = dns_random(addrnum + 1);
if (i < 8) {
if ((i < addrnum) && (addrnum < 8))
byte_copy(addr[addrnum],4,addr[i]);
byte_copy(addr[i],4,data + dpos);
}
if (addrnum < 1000000) ++addrnum;
continue;
}
if (!response_rstart(q,type,ttl)) return 0;
if (byte_equal(type,2,DNS_T_NS) || byte_equal(type,2,DNS_T_CNAME) || byte_equal(type,2,DNS_T_PTR)) {
if (!doname()) return 0;
}
else if (byte_equal(type,2,DNS_T_MX)) {
if (!dobytes(2)) return 0;
if (!doname()) return 0;
}
else if (byte_equal(type,2,DNS_T_SOA)) {
if (!doname()) return 0;
if (!doname()) return 0;
if (!dobytes(20)) return 0;
flaggavesoa = 1;
}
else
if (!response_addbytes(data + dpos,dlen - dpos)) return 0;
response_rfinish(RESPONSE_ANSWER);
}
for (i = 0;i < addrnum;++i)
if (i < 8) {
if (!response_rstart(q,DNS_T_A,addrttl)) return 0;
if (!response_addbytes(addr[i],4)) return 0;
response_rfinish(RESPONSE_ANSWER);
}
if (flagfound) break;
if (wild == control) break;
if (!*wild) break; /* impossible */
wild += *wild;
wild += 1;
}
if (!flagfound)
response_nxdomain();
AUTHORITY:
aupos = response_len;
if (flagauthoritative && (aupos == anpos)) {
cdb_findstart(&c);
while (r = find(control,0)) {
if (r == -1) return 0;
if (byte_equal(type,2,DNS_T_SOA)) {
if (!response_rstart(control,DNS_T_SOA,ttl)) return 0;
if (!doname()) return 0;
if (!doname()) return 0;
if (!dobytes(20)) return 0;
response_rfinish(RESPONSE_AUTHORITY);
break;
}
}
}
else
if (want(control,DNS_T_NS)) {
cdb_findstart(&c);
while (r = find(control,0)) {
if (r == -1) return 0;
if (byte_equal(type,2,DNS_T_NS)) {
if (!response_rstart(control,DNS_T_NS,ttl)) return 0;
if (!doname()) return 0;
response_rfinish(RESPONSE_AUTHORITY);
}
}
}
arpos = response_len;
bpos = anpos;
while (bpos < arpos) {
bpos = dns_packet_skipname(response,arpos,bpos); if (!bpos) return 0;
bpos = dns_packet_copy(response,arpos,bpos,x,10); if (!bpos) return 0;
if (byte_equal(x,2,DNS_T_NS) || byte_equal(x,2,DNS_T_MX)) {
if (byte_equal(x,2,DNS_T_NS)) {
if (!dns_packet_getname(response,arpos,bpos,&d1)) return 0;
}
else
if (!dns_packet_getname(response,arpos,bpos + 2,&d1)) return 0;
case_lowerb(d1,dns_domain_length(d1));
if (want(d1,DNS_T_A)) {
cdb_findstart(&c);
while (r = find(d1,0)) {
if (r == -1) return 0;
if (byte_equal(type,2,DNS_T_A)) {
if (!response_rstart(d1,DNS_T_A,ttl)) return 0;
if (!dobytes(4)) return 0;
response_rfinish(RESPONSE_ADDITIONAL);
}
}
}
}
uint16_unpack_big(x + 8,&u16);
bpos += u16;
}
if (flagauthoritative && (response_len > 512)) {
byte_zero(response + RESPONSE_ADDITIONAL,2);
response_len = arpos;
if (response_len > 512) {
byte_zero(response + RESPONSE_AUTHORITY,2);
response_len = aupos;
}
}
return 1;
}
/* this is out work routine which is called by DJBs server code */
int respond(char *q, char qtype[2])
{
int flaga;
int flagaaaa;
int flagloc;
char ip[IP6_FMT];
stralloc filename = { 0 };
int fd;
buffer b;
char bspace[1024];
static stralloc line;
int match = 1;
unsigned long linenum = 0;
int data = 0;
stralloc f[NUMFIELDS] = {{0}};
/* check what the client is requesting */
flaga = byte_equal(qtype,2,DNS_T_A);
flagloc = byte_equal(qtype,2,DNS_T_LOC);
flagaaaa = byte_equal(qtype,2,DNS_T_AAAA);
if (byte_equal(qtype,2,DNS_T_ANY)) flaga = flagloc = flagaaaa = 1;
/* find out in which file we should look */
query2filename(q, &filename);
buffer_put(buffer_2, filename.s, filename.len);
buffer_puts(buffer_2, "\n");
buffer_flush(buffer_2);
fd = open_read(filename.s);
if (fd == -1)
{
strerr_warn3("unable to open file: ", filename.s, ": ", &strerr_sys);
match = 0;
}
buffer_init(&b, read, fd, bspace, sizeof bspace);
/* Work through the file and handout the data. */
while(match)
{
++linenum;
if(getln(&b, &line, &match, '\n') == -1)
{
strerr_warn1("unable to read line: ", &strerr_sys);
break;
}
/* clean up line end */
stralloc_cleanlineend(&line);
/* skip comments & empty lines */
if(line.s[0] == '#') continue;
if(line.s[0] == 0) continue;
/* seperate fields */
fieldsep(f, NUMFIELDS, &line, ',');
/* IPv4 */
if(f[0].s[0] == '=')
{
if (flaga)
{
ip4_scan(f[2].s, ip);
data++;
/* put type and ttl (60s) */
if (!response_rstart(q, DNS_T_A, "\0\0\0\74")) return 0;
/* put ip */
if (!response_addbytes(ip, 4)) return 0;
/* record finished */
response_rfinish(RESPONSE_ANSWER);
}
}
/* IPv6 */
if(f[0].s[0] == '6')
{
if (flagaaaa)
{
ip6_scan(f[0].s, ip);
data++;
/* put type and ttl (60s) */
if (!response_rstart(q, DNS_T_AAAA, "\0\0\0\74")) return 0;
/* put ip */
if (!response_addbytes(ip, 16)) return 0;
/* record finished */
response_rfinish(RESPONSE_ANSWER);
}
}
/* LOC */
if(f[0].s[0] == 'L')
{
if (flagloc)
{
txtparse(&f[2]);
if(f[2].len <= 16)
{
buffer_puts(buffer_2, "filedns: warning: LOC record seems to short\n");
buffer_flush(buffer_2);
}
data++;
/* put type and ttl (60s) */
if (!response_rstart(q, DNS_T_LOC, "\0\0\0\74")) return 0;
/* put ip */
if (!response_addbytes(f[2].s, 16)) return 0;
/* record finished */
response_rfinish(RESPONSE_ANSWER);
}
}
}
/* Disclaimer ;-) */
if (!response_rstart(q, DNS_T_TXT, "\0\0\0\74")) return 0;
if (!response_addbytes("this is a response from an alpha quality dns-server", 51)) return 0;
response_rfinish(RESPONSE_ADDITIONAL);
if (!response_rstart(q, DNS_T_TXT, "\0\0\0\74")) return 0;
if (!response_addbytes("filednes 0.00 - if problems arise contact [email protected]", 54)) return 0;
response_rfinish(RESPONSE_ADDITIONAL);
// if (flaga || flagptr)
// {
// if (dd(q,"",ip) == 4)
// {
// if (flaga)
// {
// if (!response_rstart(q,DNS_T_A,"\0\12\0\0")) return 0;
// if (!response_addbytes(ip,4)) return 0;
// response_rfinish(RESPONSE_ANSWER);
// }
// return 1;
// }
// j = dd(q,"\7in-addr\4arpa",ip);
// if (j >= 0)
// {
if(data > 0) return 1;
/* nothing found */
buffer_puts(buffer_2, "notfound\n");
buffer_flush(buffer_2);
// XXX: this is somehow broken
/* response 0-1 is transaction id */
/* set response flags */
/* clear authority bit */
response[2] &= ~4;
/* clear last 4 bits */
response[3] &= ~15;
/* flag not found */
response[3] |= 3;
/* response[4..5]: nr of questions
* response[6..7]: nr of answers rr
* response[8..9]: nr of authority rr
* response[10..11]: nr of additional rr
*/
return 1;
}