ref: dc593372bfc4224c6cf91d2031d0ad0aeadaddfe
dir: /sys/src/cmd/ndb/dblookup.c/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ndb.h>
#include <ip.h>
#include <ctype.h>
#include "dns.h"
enum {
Nibwidth = 4,
Nibmask = (1<<Nibwidth) - 1,
V6maxrevdomdepth = 128 / Nibwidth, /* bits / bits-per-nibble */
/*
* ttl for generated ptr records. it was zero, which might seem
* like a good idea, but some dns implementations seem to be
* confused by a zero ttl, and instead of using the data and then
* discarding the RR, they conclude that they don't have valid data.
*/
Ptrttl = 2*Min,
};
static Ndb *db;
static Ndbtuple *mydoms;
static QLock dblock;
static Ipifc *ipifcs;
static QLock ipifclock;
static RR* addr4rr(Ndbtuple*, Ndbtuple*);
static RR* addr6rr(Ndbtuple*, Ndbtuple*);
static RR* addrrr(Ndbtuple*, Ndbtuple*);
static RR* cnamerr(Ndbtuple*, Ndbtuple*);
static void createptrs(void);
static RR* dblookup1(char*, int, int, int);
static RR* doaxfr(Ndb*, char*);
static Ndbtuple*look(Ndbtuple*, Ndbtuple*, char*);
static RR* mxrr(Ndbtuple*, Ndbtuple*);
static RR* nsrr(Ndbtuple*, Ndbtuple*);
static RR* ptrrr(Ndbtuple*, Ndbtuple*);
static RR* soarr(Ndbtuple*, Ndbtuple*);
static RR* srvrr(Ndbtuple*, Ndbtuple*);
static RR* txtrr(Ndbtuple*, Ndbtuple*);
static RR* caarr(Ndbtuple*, Ndbtuple*);
static int implemented[] =
{
[Ta] 1,
[Taaaa] 1,
[Tcname] 1,
[Tmx] 1,
[Tns] 1,
[Tptr] 1,
[Tsoa] 1,
[Tsrv] 1,
[Ttxt] 1,
[Tcaa] 1,
};
static void
nstrcpy(char *to, char *from, int len)
{
strncpy(to, from, len);
to[len-1] = 0;
}
int
opendatabase(void)
{
char netdbnm[256];
Ndb *xdb, *netdb;
if(db != nil)
return 0;
xdb = ndbopen(dbfile); /* /lib/ndb */
snprint(netdbnm, sizeof netdbnm, "%s/ndb", mntpt);
for(netdb = xdb; netdb; netdb = netdb->next)
if(strcmp(netdb->file, netdbnm) == 0){
db = xdb;
return 0;
}
netdb = ndbopen(netdbnm); /* /net/ndb */
if(netdb)
netdb->nohash = 1;
db = ndbcat(netdb, xdb); /* both */
return db!=nil ? 0: -1;
}
/*
* lookup an RR in the network database, look for matches
* against both the domain name and the wildcarded domain name.
*
* the lock makes sure only one process can be accessing the data
* base at a time. This is important since there's a lot of
* shared state there.
*
* e.g. for x.research.bell-labs.com, first look for a match against
* the x.research.bell-labs.com. If nothing matches,
* try *.research.bell-labs.com.
*/
RR*
dblookup(char *name, int class, int type, int auth, int ttl)
{
int err;
char buf[Domlen], *wild;
RR *rp, *tp;
DN *dp, *ndp;
/* so far only internet lookups are implemented */
if(class != Cin)
return nil;
err = Rname;
rp = nil;
if(type == Tall){
for (type = 0; type < nelem(implemented); type++)
if(implemented[type])
rrcat(&rp, dblookup(name, class, type, auth, ttl));
return rp;
}
qlock(&dblock);
dp = idnlookup(name, class, 1);
if(opendatabase() < 0)
goto out;
if(dp->rr)
err = Rok;
/* first try the given name */
if(cfg.cachedb)
rp = rrlookup(dp, type, NOneg);
else
rp = dblookup1(name, type, auth, ttl);
if(rp)
goto out;
/* walk the domain name trying the wildcard '*' at each position */
for(wild = strchr(name, '.'); wild; wild = strchr(wild+1, '.')){
snprint(buf, sizeof buf, "*%s", wild);
ndp = idnlookup(buf, class, 1);
if(ndp->rr)
err = Rok;
if(cfg.cachedb)
rp = rrlookup(ndp, type, NOneg);
else
rp = dblookup1(buf, type, auth, ttl);
if(rp)
break;
}
out:
/* add owner to uncached records */
if(rp)
for(tp = rp; tp; tp = tp->next)
tp->owner = dp;
else {
/*
* don't call it non-existent if it's not ours
* (unless we're a resolver).
*/
if(err == Rname && (!inmyarea(dp->name) || cfg.resolver))
err = Rserver;
dp->respcode = err;
}
qunlock(&dblock);
return rp;
}
static ulong
intval(Ndbtuple *entry, Ndbtuple *pair, char *attr, ulong def)
{
Ndbtuple *t = look(entry, pair, attr);
return (t? strtoul(t->val, 0, 10): def);
}
static void
mklowcase(char *cp)
{
Rune r;
while(*cp != 0){
chartorune(&r, cp);
r = tolowerrune(r);
cp += runetochar(cp, &r);
}
}
/*
* lookup an RR in the network database
*/
static RR*
dblookup1(char *name, int type, int auth, int ttl)
{
Ndbtuple *t, *nt;
RR *rp, *list, **l;
Ndbs s;
char dname[Domlen];
char *attr, *attr2;
DN *dp;
RR *(*f)(Ndbtuple*, Ndbtuple*);
int found, x;
dp = nil;
attr2 = nil;
switch(type){
case Tptr:
attr = "ptr";
f = ptrrr;
break;
case Ta:
attr = "ip";
f = addr4rr;
break;
case Taaaa:
attr = "ip";
attr2 = "ipv6";
f = addr6rr;
break;
case Tns:
attr = "ns";
f = nsrr;
break;
case Tsoa:
attr = "soa";
f = soarr;
break;
case Tsrv:
attr = "srv";
f = srvrr;
break;
case Ttxt:
attr = "txt";
attr2 = "txtrr"; /* obsolete */
f = txtrr;
break;
case Tmx:
attr = "mx";
f = mxrr;
break;
case Tcname:
attr = "cname";
f = cnamerr;
break;
case Taxfr:
case Tixfr:
return doaxfr(db, name);
case Tcaa:
attr = "caa";
f = caarr;
break;
default:
if(debug)
dnslog("dblookup1(%s) bad type", name);
return nil;
}
/*
* find a matching entry in the database
*/
t = nil;
nstrcpy(dname, name, sizeof dname);
for(x=0; x<4; x++){
switch(x){
case 1: /* try unicode */
if(idn2utf(name, dname, sizeof dname) < 0){
nstrcpy(dname, name, sizeof dname);
continue;
}
if(strcmp(name, dname) == 0)
continue;
break;
case 3: /* try ascii (lower case) */
if(utf2idn(name, dname, sizeof dname) < 0)
continue;
case 2:
mklowcase(dname);
if(strcmp(name, dname) == 0)
continue;
break;
}
for(nt = ndbsearch(db, &s, "dom", dname); nt != nil; nt = ndbsnext(&s, "dom", dname)) {
if(ndbfindattr(nt, s.t, attr) != nil
|| attr2 != nil && ndbfindattr(nt, s.t, attr2) != nil)
t = ndbconcatenate(t, ndbreorder(nt, s.t));
else
ndbfree(nt);
}
if(t == nil && strchr(dname, '.') == nil) {
for(nt = ndbsearch(db, &s, "sys", dname); nt != nil; nt = ndbsnext(&s, "sys", dname)) {
if(ndbfindattr(nt, s.t, attr) != nil
|| attr2 != nil && ndbfindattr(nt, s.t, attr2) != nil)
t = ndbconcatenate(t, ndbreorder(nt, s.t));
else
ndbfree(nt);
}
}
s.t = t;
if(t != nil)
break;
}
if(t == nil)
return nil;
/* search whole entry for default domain name */
for(nt = t; nt; nt = nt->entry) {
if(strcmp(nt->attr, "dom") == 0) {
nstrcpy(dname, nt->val, sizeof dname);
break;
}
}
/* ttl is maximum of soa minttl and entry's ttl ala rfc883 */
x = intval(t, s.t, "ttl", 0);
if(x > ttl)
ttl = x;
/* default ttl is one day */
if(ttl < 0)
ttl = DEFTTL;
/*
* The database has 2 levels of precedence; line and entry.
* Pairs on the same line bind tighter than pairs in the
* same entry, so we search the line first.
*/
found = 0;
list = 0;
l = &list;
for(nt = s.t;; ){
if(found == 0 && strcmp(nt->attr, "dom") == 0){
nstrcpy(dname, nt->val, sizeof dname);
found = 1;
}
if((strcmp(attr, nt->attr) == 0 || attr2 != nil && strcmp(attr2, nt->attr) == 0)
&& (rp = (*f)(t, nt)) != nil){
rp->auth = auth;
rp->db = 1;
if(ttl)
rp->ttl = ttl;
if(dp == nil)
dp = idnlookup(dname, Cin, 1);
rp->owner = dp;
*l = rp;
l = &rp->next;
nt->ptr = 1;
}
nt = nt->line;
if(nt == s.t)
break;
}
/* search whole entry */
for(nt = t; nt; nt = nt->entry){
if(nt->ptr == 0
&& (strcmp(attr, nt->attr) == 0 || attr2 != nil && strcmp(attr2, nt->attr) == 0)
&& (rp = (*f)(t, nt)) != nil){
rp->auth = auth;
rp->db = 1;
if(ttl)
rp->ttl = ttl;
if(dp == nil)
dp = idnlookup(dname, Cin, 1);
rp->owner = dp;
*l = rp;
l = &rp->next;
}
}
ndbfree(t);
unique(list);
return list;
}
/*
* make various types of resource records from a database entry
*/
static RR*
addr4rr(Ndbtuple*, Ndbtuple *pair)
{
RR *rp;
uchar ip[IPaddrlen];
if(parseip(ip, pair->val) == -1)
return nil;
if(!isv4(ip) || strcmp(pair->attr, "ipv6") == 0)
return nil;
rp = rralloc(Ta);
rp->ip = ipalookup(ip, Cin, 1);
return rp;
}
static RR*
addr6rr(Ndbtuple*, Ndbtuple *pair)
{
RR *rp;
uchar ip[IPaddrlen];
if(parseip(ip, pair->val) == -1)
return nil;
if(isv4(ip) && strcmp(pair->attr, "ipv6") != 0)
return nil;
rp = rralloc(Taaaa);
rp->ip = ipalookup(ip, Cin, 1);
return rp;
}
static RR*
addrrr(Ndbtuple*, Ndbtuple *pair)
{
RR *rp;
uchar ip[IPaddrlen];
if(parseip(ip, pair->val) == -1)
return nil;
rp = rralloc(isv4(ip) && strcmp(pair->attr, "ipv6") != 0 ? Ta : Taaaa);
rp->ip = ipalookup(ip, Cin, 1);
return rp;
}
/*
* txt rr strings are at most Strlen-1 bytes long. one
* can represent longer strings by multiple concatenated
* < Strlen byte ones.
*/
static RR*
txtrr(Ndbtuple*, Ndbtuple *pair)
{
RR *rp;
Txt *t, **l;
int i, n, len, sofar;
rp = rralloc(Ttxt);
l = &rp->txt;
rp->txt = nil;
len = strlen(pair->val);
sofar = 0;
while(len > sofar){
t = emalloc(sizeof(*t));
t->next = nil;
n = len-sofar;
if(n >= Strlen)
n = Strlen-1;
t->data = emalloc(n);
/* see bslashfmt() */
for(i = 0; i < n && sofar < len; i++){
uint c = pair->val[sofar++];
if(c == '\\' && sofar < len){
if(pair->val[sofar] >= '0' && pair->val[sofar] <= '9'){
c = pair->val[sofar++] - '0';
while(pair->val[sofar] >= '0' && pair->val[sofar] <= '9')
c = (c * 10) + (pair->val[sofar++] - '0');
} else {
c = pair->val[sofar++];
}
}
t->data[i] = c;
}
t->dlen = i;
*l = t;
l = &t->next;
}
return rp;
}
static RR*
cnamerr(Ndbtuple*, Ndbtuple *pair)
{
RR *rp;
rp = rralloc(Tcname);
rp->host = idnlookup(pair->val, Cin, 1);
return rp;
}
static RR*
mxrr(Ndbtuple *entry, Ndbtuple *pair)
{
RR *rp;
rp = rralloc(Tmx);
rp->host = idnlookup(pair->val, Cin, 1);
rp->pref = intval(entry, pair, "pref", 1);
return rp;
}
static RR*
nsrr(Ndbtuple *entry, Ndbtuple *pair)
{
RR *rp;
Ndbtuple *t;
rp = rralloc(Tns);
rp->host = idnlookup(pair->val, Cin, 1);
t = look(entry, pair, "soa");
if(t && t->val[0] == 0)
rp->local = 1;
return rp;
}
static RR*
ptrrr(Ndbtuple*, Ndbtuple *pair)
{
RR *rp;
rp = rralloc(Tns);
rp->ptr = dnlookup(pair->val, Cin, 1);
return rp;
}
static RR*
soarr(Ndbtuple *entry, Ndbtuple *pair)
{
RR *rp;
Ndbtuple *ns, *mb, *t;
char mailbox[Domlen];
Ndb *ndb;
char *p;
rp = rralloc(Tsoa);
rp->soa->serial = 1;
for(ndb = db; ndb; ndb = ndb->next)
if(ndb->mtime > rp->soa->serial)
rp->soa->serial = ndb->mtime;
rp->soa->retry = intval(entry, pair, "retry", Hour);
rp->soa->expire = intval(entry, pair, "expire", Day);
rp->soa->minttl = intval(entry, pair, "ttl", Day);
rp->soa->refresh = intval(entry, pair, "refresh", Day);
rp->soa->serial = intval(entry, pair, "serial", rp->soa->serial);
ns = look(entry, pair, "ns");
if(ns == nil)
ns = look(entry, pair, "dom");
rp->host = idnlookup(ns->val, Cin, 1);
/* accept all of:
* mbox=person
* mbox=person@machine.dom
* mbox=person.machine.dom
*/
mb = look(entry, pair, "mbox");
if(mb == nil)
mb = look(entry, pair, "mb");
if(mb)
if(strchr(mb->val, '.')) {
p = strchr(mb->val, '@');
if(p != nil)
*p = '.';
rp->rmb = idnlookup(mb->val, Cin, 1);
} else {
snprint(mailbox, sizeof mailbox, "%s.%s",
mb->val, ns->val);
rp->rmb = idnlookup(mailbox, Cin, 1);
}
else {
snprint(mailbox, sizeof mailbox, "postmaster.%s", ns->val);
rp->rmb = idnlookup(mailbox, Cin, 1);
}
/*
* hang dns slaves off of the soa. this is
* for managing the area.
*/
for(t = entry; t != nil; t = t->entry)
if(strcmp(t->attr, "dnsslave") == 0)
addserver(&rp->soa->slaves, t->val);
return rp;
}
static RR*
srvrr(Ndbtuple *entry, Ndbtuple *pair)
{
RR *rp;
rp = rralloc(Tsrv);
rp->host = idnlookup(pair->val, Cin, 1);
rp->srv->pri = intval(entry, pair, "pri", 0);
rp->srv->weight = intval(entry, pair, "weight", 0);
/* TODO: translate service name to port # */
rp->port = intval(entry, pair, "port", 0);
return rp;
}
static RR*
caarr(Ndbtuple *entry, Ndbtuple *pair)
{
Ndbtuple *tag;
RR *rp;
rp = rralloc(Tcaa);
rp->caa->flags = intval(entry, pair, "flags", 0);
rp->caa->data = (uchar*)estrdup(pair->val);
rp->caa->dlen = strlen((char*)rp->caa->data);
if((tag = look(entry, pair, "tag")) != nil)
rp->caa->tag = dnlookup(tag->val, Cin, 1);
else
rp->caa->tag = dnlookup("issue", Cin, 1);
return rp;
}
/*
* Look for a pair with the given attribute. look first on the same line,
* then in the whole entry.
*/
static Ndbtuple*
look(Ndbtuple *entry, Ndbtuple *line, char *attr)
{
Ndbtuple *nt;
/* first look on same line (closer binding) */
for(nt = line;;){
if(strcmp(attr, nt->attr) == 0)
return nt;
nt = nt->line;
if(nt == line)
break;
}
/* search whole tuple */
for(nt = entry; nt; nt = nt->entry)
if(strcmp(attr, nt->attr) == 0)
return nt;
return 0;
}
/* these are answered specially by the tcp version */
static RR*
doaxfr(Ndb *db, char *name)
{
USED(db, name);
return nil;
}
/*
* read the database into the cache
*/
static void
dbpair2cache(DN *dp, Ndbtuple *entry, Ndbtuple *pair)
{
RR *rp;
static ulong ord;
rp = 0;
if(strcmp(pair->attr, "ip") == 0 ||
strcmp(pair->attr, "ipv6") == 0) {
dp->ordinal = ord++;
rp = addrrr(entry, pair);
}
else if(strcmp(pair->attr, "ns") == 0)
rp = nsrr(entry, pair);
else if(strcmp(pair->attr, "soa") == 0)
rp = soarr(entry, pair);
else if(strcmp(pair->attr, "mx") == 0)
rp = mxrr(entry, pair);
else if(strcmp(pair->attr, "srv") == 0)
rp = srvrr(entry, pair);
else if(strcmp(pair->attr, "cname") == 0)
rp = cnamerr(entry, pair);
else if(strcmp(pair->attr, "txtrr") == 0) /* obsolete */
rp = txtrr(entry, pair);
else if(strcmp(pair->attr, "txt") == 0)
rp = txtrr(entry, pair);
else if(strcmp(pair->attr, "caa") == 0)
rp = caarr(entry, pair);
if(rp == nil)
return;
rp->owner = dp;
rp->db = 1;
rp->ttl = intval(entry, pair, "ttl", rp->ttl);
if(rp->type == Tsoa)
addarea(rp, pair);
rrattach(rp, Notauthoritative);
}
static void
dbtuple2cache(Ndbtuple *t)
{
Ndbtuple *et, *nt;
DN *dp;
for(et = t; et; et = et->entry)
if(strcmp(et->attr, "dom") == 0){
dp = idnlookup(et->val, Cin, 1);
/* first same line */
for(nt = et->line; nt != et; nt = nt->line){
dbpair2cache(dp, t, nt);
nt->ptr = 1;
}
/* then rest of entry */
for(nt = t; nt; nt = nt->entry){
if(nt->ptr == 0)
dbpair2cache(dp, t, nt);
nt->ptr = 0;
}
}
}
static void
dbfile2cache(Ndb *db)
{
Ndbtuple *t;
if(debug)
dnslog("rereading %s", db->file);
Bseek(&db->b, 0, 0);
while(t = ndbparse(db)){
dbtuple2cache(t);
ndbfree(t);
}
}
/*
* get all my xxx
* caller ndbfrees the result
*/
Ndbtuple*
lookupinfo(char *attr)
{
Ndbtuple *t, *nt;
char ip[64];
Ipifc *ifc;
Iplifc *lifc;
t = nil;
qlock(&dblock);
if(opendatabase() < 0){
qunlock(&dblock);
return nil;
}
qlock(&ipifclock);
if(ipifcs == nil)
ipifcs = readipifc(mntpt, ipifcs, -1);
for(ifc = ipifcs; ifc != nil; ifc = ifc->next){
for(lifc = ifc->lifc; lifc != nil; lifc = lifc->next){
snprint(ip, sizeof(ip), "%I", lifc->ip);
nt = ndbipinfo(db, "ip", ip, &attr, 1);
t = ndbconcatenate(t, nt);
}
}
qunlock(&ipifclock);
qunlock(&dblock);
return ndbdedup(t);
}
void
db2cache(int doit)
{
ulong youngest;
Ndb *ndb;
Dir *d;
static Ndbtuple *olddoms;
static Area *oldowned, *olddelegated;
static ulong lastcheck, lastyoungest;
/* no faster than once every 2 minutes */
if(now < lastcheck + 2*Min && !doit)
return;
qlock(&dblock);
if(opendatabase() < 0){
qunlock(&dblock);
return;
}
qlock(&ipifclock);
ipifcs = readipifc(mntpt, ipifcs, -1);
qunlock(&ipifclock);
/*
* file may be changing as we are reading it, so loop till
* mod times are consistent.
*
* we don't use the times in the ndb records because they may
* change outside of refreshing our cached knowledge.
*/
for(;;){
lastcheck = now;
youngest = 0;
for(ndb = db; ndb; ndb = ndb->next)
/* dirfstat avoids walking the mount table each time */
if((d = dirfstat(Bfildes(&ndb->b))) != nil ||
(d = dirstat(ndb->file)) != nil){
if(d->mtime > youngest)
youngest = d->mtime;
free(d);
}
if(!doit && youngest == lastyoungest)
break;
doit = 0;
lastyoungest = youngest;
/* reopen all the files (to get oldest for time stamp) */
for(ndb = db; ndb; ndb = ndb->next)
ndbreopen(ndb);
/* mark all db records as timed out */
dnagedb();
/* forget our area definition */
freeareas(&oldowned), freeareas(&olddelegated);
oldowned = owned, olddelegated = delegated;
owned = nil, delegated = nil;
if(cfg.cachedb){
/* read in new entries */
for(ndb = db; ndb; ndb = ndb->next)
dbfile2cache(ndb);
}
/*
* mark as authoritative anything in our domain,
* delete timed out db records
*/
dnauthdb();
createptrs();
}
qunlock(&dblock);
ndbfree(olddoms);
olddoms = mydoms;
mydoms = lookupinfo("dom");
}
/*
* return non-zero if this is a bad delegation
*/
int
baddelegation(RR *rp, RR *nsrp, uchar *addr)
{
Ndbtuple *nt;
if(rp->type != Tns)
return 0;
/* see if delegating to us what we don't own */
for(nt = mydoms; nt != nil; nt = nt->entry)
if(rp->host && cistrcmp(rp->host->name, nt->val) == 0)
break;
if(nt == nil || inmyarea(rp->owner->name))
return 0;
dnslog("bad delegation %R from %I/%s; "
"no further logging of them",
rp, addr, nsrp->host->name);
return 1;
}
int
myip(uchar *ip)
{
Ipifc *ifc;
qlock(&ipifclock);
for(ifc = ipifcs; ifc != nil; ifc = ifc->next){
if(iplocalonifc(ifc, ip) != nil){
qunlock(&ipifclock);
return 1;
}
}
qunlock(&ipifclock);
return 0;
}
int
localip(uchar *ip)
{
Ipifc *ifc;
qlock(&ipifclock);
for(ifc = ipifcs; ifc != nil; ifc = ifc->next){
if(ipremoteonifc(ifc, ip) != nil){
qunlock(&ipifclock);
return 1;
}
}
qunlock(&ipifclock);
return 0;
}
static void
addlocaldnsserver(DN *dp, int class, char *addr, int i)
{
uchar ip[IPaddrlen];
DN *nsdp, *ipdp;
RR *rp, *tp;
int type, n;
char buf[32];
if(parseip(ip, addr) == -1 || ipcmp(ip, IPnoaddr) == 0){
dnslog("rejecting bad ip %s as local dns server", addr);
return;
}
/* reject our own ip addresses so we don't query ourselves */
if(cfg.serve && myip(ip)){
dnslog("rejecting my ip %I as local dns server", ip);
return;
}
/* A or AAAA record */
type = isv4(ip) ? Ta : Taaaa;
ipdp = ipalookup(ip, class, 1);
/* check duplicate ip */
for(n = 0; n < i; n++){
snprint(buf, sizeof buf, "local#dns#server%d", n);
nsdp = dnlookup(buf, class, 0);
if(nsdp == nil)
continue;
rp = rrlookup(nsdp, type, NOneg);
for(tp = rp; tp != nil; tp = tp->next){
if(tp->ip == ipdp){
dnslog("rejecting duplicate local dns server ip %I", ip);
rrfreelist(rp);
return;
}
}
rrfreelist(rp);
}
snprint(buf, sizeof buf, "local#dns#server%d", i);
nsdp = dnlookup(buf, class, 1);
/* ns record for name server, make up an impossible name */
rp = rralloc(Tns);
rp->host = nsdp;
rp->owner = dp; /* e.g., local#dns#servers */
rp->local = 1;
rp->db = 1;
rp->ttl = 10*Min;
rrattach(rp, Authoritative); /* will not attach rrs in my area */
rp = rralloc(type);
rp->ip = ipdp;
rp->owner = nsdp;
rp->db = 1;
rp->ttl = 10*Min;
rrattach(rp, Authoritative); /* will not attach rrs in my area */
dnslog("added local dns server %s at %I", buf, ip);
}
/*
* return list of dns server addresses to use when
* acting just as a resolver.
*/
RR*
dnsservers(int class)
{
int i, n;
char *p;
char *args[16];
Ndbtuple *t, *nt;
RR *nsrp;
DN *dp;
dp = dnlookup("local#dns#servers", class, 1);
nsrp = rrlookup(dp, Tns, NOneg);
if(nsrp != nil)
return nsrp;
p = getenv("DNSSERVER"); /* list of ip addresses */
if(p != nil && (n = tokenize(p, args, nelem(args))) > 0){
for(i = 0; i < n; i++)
addlocaldnsserver(dp, class, args[i], i);
} else {
t = lookupinfo("@dns"); /* @dns=ip1 @dns=ip2 ... */
if(t == nil)
return nil;
i = 0;
for(nt = t; nt != nil; nt = nt->entry){
addlocaldnsserver(dp, class, nt->val, i);
i++;
}
ndbfree(t);
}
free(p);
return rrlookup(dp, Tns, NOneg);
}
static void
addlocaldnsdomain(DN *dp, int class, char *domain)
{
RR *rp;
/* ptr record */
rp = rralloc(Tptr);
rp->ptr = dnlookup(domain, class, 1);
rp->owner = dp;
rp->db = 1;
rp->ttl = 10*Min;
rrattach(rp, Authoritative);
}
/*
* return list of domains to use when resolving names without '.'s
*/
RR*
domainlist(int class)
{
Ndbtuple *t, *nt;
RR *rp;
DN *dp;
dp = dnlookup("local#dns#domains", class, 1);
rp = rrlookup(dp, Tptr, NOneg);
if(rp != nil)
return rp;
t = lookupinfo("dnsdomain");
if(t == nil)
return nil;
for(nt = t; nt != nil; nt = nt->entry)
addlocaldnsdomain(dp, class, nt->val);
ndbfree(t);
return rrlookup(dp, Tptr, NOneg);
}
char *v4ptrdom = ".in-addr.arpa";
char *v6ptrdom = ".ip6.arpa"; /* ip6.int deprecated, rfc 3152 */
char *attribs[] = {
"ipmask",
0
};
/*
* create ptrs that are in our v4 areas
*/
static void
createv4ptrs(void)
{
int len, dlen, n;
char *dom;
char buf[Domlen], ipa[64];
char *f[40];
uchar net[IPaddrlen], mask[IPaddrlen];
Area *s;
Ndbtuple *t, *nt;
dlen = strlen(v4ptrdom);
for(s = owned; s; s = s->next){
dom = s->soarr->owner->name;
len = strlen(dom);
if((len <= dlen || cistrcmp(dom+len-dlen, v4ptrdom) != 0) &&
cistrcmp(dom, v4ptrdom+1) != 0)
continue;
/* get mask and net value */
nstrcpy(buf, dom, sizeof buf);
/* buf contains something like 178.204.in-addr.arpa (n==4) */
n = getfields(buf, f, nelem(f), 0, ".");
memset(mask, 0xff, IPaddrlen);
ipmove(net, v4prefix);
switch(n){
case 3: /* /8 */
net[IPv4off] = atoi(f[0]);
mask[IPv4off+1] = 0;
mask[IPv4off+2] = 0;
mask[IPv4off+3] = 0;
break;
case 4: /* /16 */
net[IPv4off] = atoi(f[1]);
net[IPv4off+1] = atoi(f[0]);
mask[IPv4off+2] = 0;
mask[IPv4off+3] = 0;
break;
case 5: /* /24 */
net[IPv4off] = atoi(f[2]);
net[IPv4off+1] = atoi(f[1]);
net[IPv4off+2] = atoi(f[0]);
mask[IPv4off+3] = 0;
break;
case 6: /* rfc2317: classless in-addr.arpa delegation */
net[IPv4off] = atoi(f[3]);
net[IPv4off+1] = atoi(f[2]);
net[IPv4off+2] = atoi(f[1]);
net[IPv4off+3] = atoi(f[0]);
snprint(ipa, sizeof(ipa), "%I", net);
t = ndbipinfo(db, "ip", ipa, attribs, 1);
if(t == nil) /* could be a reverse with no forward */
continue;
nt = look(t, t, "ipmask");
if(nt == nil || parseipmask(mask, nt->val, 1) == -1){
ndbfree(t);
continue;
}
ndbfree(t);
n = 5;
break;
default:
continue;
}
/*
* go through all domain entries looking for RR's
* in this network and create ptrs.
* +2 for ".in-addr.arpa".
*/
dnptr(net, mask, dom, Ta, 4+2-n, Ptrttl);
}
}
/* convert bytes to nibbles, big-endian */
void
bytes2nibbles(uchar *nibbles, uchar *bytes, int nbytes)
{
while (nbytes-- > 0) {
*nibbles++ = *bytes >> Nibwidth;
*nibbles++ = *bytes++ & Nibmask;
}
}
void
nibbles2bytes(uchar *bytes, uchar *nibbles, int nnibs)
{
for (; nnibs >= 2; nnibs -= 2) {
*bytes++ = nibbles[0] << Nibwidth | (nibbles[1]&Nibmask);
nibbles += 2;
}
if (nnibs > 0)
*bytes = nibbles[0] << Nibwidth;
}
/*
* create ptrs that are in our v6 areas. see rfc3596
*/
static void
createv6ptrs(void)
{
int len, dlen, i, n, pfxnibs;
char *dom;
char buf[Domlen];
char *f[40];
uchar net[IPaddrlen], mask[IPaddrlen];
uchar nibnet[IPaddrlen*2], nibmask[IPaddrlen*2];
Area *s;
dlen = strlen(v6ptrdom);
for(s = owned; s; s = s->next){
dom = s->soarr->owner->name;
len = strlen(dom);
if((len <= dlen || cistrcmp(dom+len-dlen, v6ptrdom) != 0) &&
cistrcmp(dom, v6ptrdom+1) != 0)
continue;
/* get mask and net value */
nstrcpy(buf, dom, sizeof buf);
/* buf contains something like 2.0.0.2.ip6.arpa (n==6) */
n = getfields(buf, f, nelem(f), 0, ".");
pfxnibs = n - 2; /* 2 for .ip6.arpa */
if (pfxnibs < 0 || pfxnibs > V6maxrevdomdepth)
continue;
memset(net, 0, IPaddrlen);
memset(mask, 0xff, IPaddrlen);
bytes2nibbles(nibnet, net, IPaddrlen);
bytes2nibbles(nibmask, mask, IPaddrlen);
/* copy prefix of f, in reverse order, to start of net. */
for (i = 0; i < pfxnibs; i++)
nibnet[i] = strtol(f[pfxnibs - 1 - i], nil, 16);
/* zero nibbles of mask after prefix in net */
memset(nibmask + pfxnibs, 0, V6maxrevdomdepth - pfxnibs);
nibbles2bytes(net, nibnet, 2*IPaddrlen);
nibbles2bytes(mask, nibmask, 2*IPaddrlen);
/*
* go through all domain entries looking for RR's
* in this network and create ptrs.
*/
dnptr(net, mask, dom, Taaaa, V6maxrevdomdepth - pfxnibs, Ptrttl);
}
}
/*
* create ptrs that are in our areas
*/
static void
createptrs(void)
{
createv4ptrs();
createv6ptrs();
}