/* $Id: filedns.c,v 1.5 2000/11/21 19:50:41 drt Exp $

*

* dnsserver serving from the filesystem

*

* $Log: filedns.c,v $

* Revision 1.5 2000/11/21 19:50:41 drt

* Updated E-Mailaddress, changed 'X' to '+' for illegal characters.

*

* Revision 1.4 2000/07/31 19:15:56 drt

* ddns-file(5) format changed

* a lot of restructuring

*

* Revision 1.3 2000/07/13 18:20:47 drt

* everything supports now DNS LOC

*

* Revision 1.2 2000/07/07 23:51:38 drt

* nearly everything works now, ddns is in a somehow usable state now.

*

* Revision 1.1 2000/04/27 09:35:33 drt

* Initial Revision

*

*/

/* XXX: do we need to handle SOA here ? */

/* XXX: we should put more authority (records) in here */

/* XXX: errorhandling is bad, distinguish not found and internal server error */

#include "open.h"

#include "buffer.h"

#include "byte.h"

#include "dd.h"

#include "dns.h"

#include "getln.h"

#include "ip4.h"

#include "ip6.h"

#include "open.h"

#include "readwrite.h"

#include "response.h"

#include "stralloc.h"

#include "strerr.h"

#include "txtparse.h"

#include "ddns.h"

static char rcsid[] = "$Id: filedns.c,v 1.5 2000/11/21 19:50:41 drt Exp $";

/* XXX: This is missing in DJBs headers, fefe should add it to libdjb (and strerr_warnXsys) */

#define DNS_T_LOC "\0\35"

#define FATAL "fatal: "

/* XXX: cleanme */

char *fatal = "filedns: fatal: ";

void die_nomem(void)

{

strerr_die1sys(111, "filedns: fatal: help - no memory ");

}

void initialize(void)

{

/* we don't need initialisation */

;

}

/* convert a query to a filename mainly by adding slashes instead of

dots (this is an abstraction) and removing anything that is not

a valid in DNS, which means A-Z and '-' */

int query2filename(char *q, stralloc *s)

{

int i;

char *p;

stralloc tmp = { 0 };

p = q;

/* XXX: handling of uppercase/lowercase is missing */

while(*p)

{

stralloc_copy(&tmp, s);

stralloc_copyb(s, "/", 1);

stralloc_catb(s, p+1, (int) *p);

/* Clean up string by changing all characters not allowed in

dnsnames to '+'. We need to do tis to keep strange meta

characters from slipping into syscalls when opening

files changing directorys */

for(i = 1; i < s->len; i++)

{

if(!(((s->s[i] >= 'a') && (s->s[i] <= 'z'))

|| ((s->s[i] >= 'A') && (s->s[i] <= 'Z'))

|| ((s->s[i] >= '0') && (s->s[i] <= '9'))

|| s->s[i] == '-'))

{

s->s[i] = '+';

}

}

stralloc_cat(s, &tmp);

p += ((int) *p) + 1;

}

stralloc_0(s);

return s->len;

}

/* 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 drt@un.bewaff.net", 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;

}