/* ans.c - Interface for text2atm and atm2text to ANS */
/* Written 1996-2000 by Werner Almesberger, EPFL-LRC/ICA */
/*
* This stuff is a temporary hack to avoid using gethostbyname_nsap and such
* without doing the "full upgrade" to getaddrinfo/getnameinfo. This also
* serves as an exercise for me to get all the details right before I propose
* a patch that would eventually end up in libc (and that should therefore be
* as stable as possible).
*/
#if HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <netdb.h>
#include <resolv.h>
#include "atm.h"
#include "atmres.h"
#define MAX_ANSWER 2048
#define MAX_NAME 1024
#define MAX_LINE 2048 /* in /etc/e164_cc */
#define E164_CC_DEFAULT_LEN 2
#define E164_CC_FILE "/etc/e164_cc"
#define GET16(pos) (((pos)[0] << 8) | (pos)[1])
static int ans(const char *text,int wanted,void *result,int res_len)
{
unsigned char answer[MAX_ANSWER];
unsigned char name[MAX_NAME];
unsigned char *pos,*data,*found;
int answer_len,name_len,data_len,found_len;
int questions,answers;
found_len = 0; /* gcc wants it */
if ((answer_len = res_search(text,C_IN,wanted,answer,MAX_ANSWER)) < 0)
return TRY_OTHER;
/*
* Response header: id, flags, #queries, #answers, #authority,
* #additional (all 16 bits)
*/
pos = answer+12;
if (answer[3] & 15) return TRY_OTHER; /* rcode != 0 */
questions = GET16(answer+4);
if (questions != 1) return TRY_OTHER; /* trouble ... */
answers = GET16(answer+6);
if (answers < 1) return TRY_OTHER;
/*
* Query: name, type (16), class (16)
*/
if ((name_len = dn_expand(answer,answer+answer_len,pos,name,MAX_NAME)) < 0)
return TRY_OTHER;
pos += name_len;
if (GET16(pos) != wanted || GET16(pos+2) != C_IN) return TRY_OTHER;
pos += 4;
/*
* Iterate over answers until we find something we like, giving priority
* to ATMA_AESA (until signaling is fixed to work with E.164 too)
*/
found = NULL;
while (answers--) {
/*
* RR: name, type (16), class (16), TTL (32), resource_len (16),
* resource_data ...
*/
if ((name_len = dn_expand(answer,answer+answer_len,pos,name,MAX_NAME))
< 0) return TRY_OTHER;
pos += name_len;
data_len = GET16(pos+8);
data = pos+10;
pos = data+data_len;
if (GET16(data-10) != wanted || GET16(data-8) != C_IN || !--data_len)
continue;
switch (wanted) {
case T_NSAP:
data_len++;
if (data_len != ATM_ESA_LEN) continue;
memcpy(((struct sockaddr_atmsvc *) result)->
sas_addr.prv,data,ATM_ESA_LEN);
return 0;
case T_ATMA:
switch (*data++) {
case ATMA_AESA:
if (data_len != ATM_ESA_LEN) continue;
memcpy(((struct sockaddr_atmsvc *) result)->
sas_addr.prv,data,ATM_ESA_LEN);
return 0;
case ATMA_E164:
if (data_len > ATM_E164_LEN) continue;
if (!found) {
found = data;
found_len = data_len;
}
break;
default:
continue;
}
case T_PTR:
if (dn_expand(answer,answer+answer_len,data,result,
res_len) < 0) return FATAL;
return 0;
default:
continue;
}
}
if (!found) return TRY_OTHER;
memcpy(((struct sockaddr_atmsvc *) result)->sas_addr.pub,found,
found_len);
((struct sockaddr_atmsvc *) result)->sas_addr.pub[found_len] = 0;
return 0;
}
int ans_byname(const char *text,struct sockaddr_atmsvc *addr,int length,
int flags)
{
if (!(flags & T2A_SVC) || length != sizeof(*addr)) return TRY_OTHER;
memset(addr,0,sizeof(*addr));
addr->sas_family = AF_ATMSVC;
if (!ans(text,T_ATMA,addr,length)) return 0;
return ans(text,T_NSAP,addr,length);
}
static int encode_nsap(char *buf,const unsigned char *addr)
{
static int fmt_dcc[] = { 2,12,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
4,2,0 };
static int fmt_e164[] = { 2,12,1,1,1,1,1,1,1,1,16,2,0 };
int *fmt;
int pos,i,j;
switch (*addr) {
case ATM_AFI_DCC:
case ATM_AFI_ICD:
case ATM_AFI_LOCAL:
case ATM_AFI_DCC_GROUP:
case ATM_AFI_ICD_GROUP:
case ATM_AFI_LOCAL_GROUP:
fmt = fmt_dcc;
break;
case ATM_AFI_E164:
case ATM_AFI_E164_GROUP:
fmt = fmt_e164;
break;
default:
return TRY_OTHER;
}
pos = 2*ATM_ESA_LEN;
for (i = 0; fmt[i]; i++) {
pos -= fmt[i];
for (j = 0; j < fmt[i]; j++)
sprintf(buf++,"%x",
(addr[(pos+j) >> 1] >> 4*(1-((pos+j) & 1))) & 0xf);
*buf++ = '.';
}
strcpy(buf,"AESA.ATMA.INT.");
return 0;
}
static int encode_nsap_new(char *buf,const unsigned char *addr)
{
int i;
int digit;
for (i = 20; i; ) {
i--;
digit = addr[i] & 0x0F;
*(buf++) = digit + (digit >= 10 ? '7' : '0');
*(buf++) = '.';
digit = ((unsigned char) (addr[i])) >> 4;
*(buf++) = digit + (digit >= 10 ? '7' : '0');
*(buf++) = '.';
}
strcpy (buf, "NSAP.INT.");
return 0;
}
static int cc_len(int p0,int p1)
{
static char *cc_table = NULL;
FILE *file;
char buffer[MAX_LINE];
char *here;
int cc;
if (!cc_table) {
if (!(cc_table = malloc(100))) {
perror("malloc");
return E164_CC_DEFAULT_LEN;
}
memset(cc_table,E164_CC_DEFAULT_LEN,100);
if (!(file = fopen(E164_CC_FILE,"r")))
perror(E164_CC_FILE);
else {
while (fgets(buffer,MAX_LINE,file)) {
here = strchr(buffer,'#');
if (here) *here = 0;
if (sscanf(buffer,"%d",&cc) == 1) {
if (cc < 10) cc_table[cc] = 1;
else if (cc < 100) cc_table[cc] = 2;
else cc_table[cc/10] = 3;
}
}
fclose(file);
}
}
if (cc_table[p0] == 1) return 1;
return cc_table[p0*10+p1];
}
static int encode_e164(char *buf,const char *addr)
{
const char *prefix,*here;
prefix = addr+cc_len(addr[0]-48,addr[1]-48);
here = strchr(addr,0);
while (here > prefix) {
*buf++ = *--here;
*buf++ = '.';
}
while (here > addr) *buf++ = *addr++;
strcpy(buf,".E164.ATMA.INT.");
return 0;
}
int ans_byaddr(char *buffer,int length,const struct sockaddr_atmsvc *addr,
int flags)
{
char tmp[MAX_NAME]; /* could be smaller ... */
int res;
if (addr->sas_addr.prv) {
res = encode_nsap(tmp,addr->sas_addr.prv);
if (!res && !ans(tmp,T_PTR,buffer,length)) return 0;
res = encode_nsap_new(tmp,addr->sas_addr.prv);
if (res < 0) return res;
return ans(tmp,T_PTR,buffer,length);
} else {
res = encode_e164(tmp,addr->sas_addr.pub);
if (res < 0) return res;
return ans(tmp,T_PTR,buffer,length);
}
}