ref: 7451bb405d9e51965ce07d55f04f43dc45b6cef9
dir: /sys/src/libndb/ndbipinfo.c/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ndb.h>
#include <ip.h>
enum
{
Ffound= 1<<0,
Fignore=1<<1,
Faddr= 1<<2,
};
static Ndbtuple* filter(Ndb *db, Ndbtuple *t, Ndbtuple *f);
static Ndbtuple* mkfilter(int argc, char **argv);
static int filtercomplete(Ndbtuple *f);
static int prefixlen(uchar *ip);
static Ndbtuple* subnet(Ndb *db, uchar *net, Ndbtuple *f, int prefix);
/* make a filter to be used in filter */
static Ndbtuple*
mkfilter(int argc, char **argv)
{
Ndbtuple *t, *first, *last;
char *p;
last = first = nil;
while(argc-- > 0){
t = ndbnew(0, 0);
if(first)
last->entry = t;
else
first = t;
last = t;
p = *argv++;
if(*p == '@'){ /* @attr=val ? */
t->ptr |= Faddr; /* return resolved address(es) */
p++;
}
strncpy(t->attr, p, sizeof(t->attr)-1);
}
ndbsetmalloctag(first, getcallerpc(&argc));
return first;
}
/* return true if every pair of filter has been used */
static int
filtercomplete(Ndbtuple *f)
{
for(; f; f = f->entry)
if((f->ptr & Fignore) == 0)
return 0;
return 1;
}
/* set the attribute of all entries in a tuple */
static Ndbtuple*
setattr(Ndbtuple *t, char *attr)
{
Ndbtuple *nt;
for(nt = t; nt; nt = nt->entry)
strcpy(nt->attr, attr);
return t;
}
/*
* return only the attr/value pairs in t maching the filter, f.
* others are freed. line structure is preserved.
*/
static Ndbtuple*
filter(Ndb *db, Ndbtuple *t, Ndbtuple *f)
{
Ndbtuple *nt, *nf, *next;
/* filter out what we don't want */
for(nt = t; nt; nt = next){
next = nt->entry;
/* look through filter */
for(nf = f; nf != nil; nf = nf->entry){
if(!(nf->ptr&Fignore) && strcmp(nt->attr, nf->attr) == 0)
break;
}
if(nf == nil){
/* remove nt from t */
t = ndbdiscard(t, nt);
} else {
if(nf->ptr & Faddr)
t = ndbsubstitute(t, nt, setattr(ndbgetipaddr(db, nt->val), nt->attr));
nf->ptr |= Ffound;
}
}
/* remember filter etnries that matched */
for(nf = f; nf != nil; nf = nf->entry)
if(nf->ptr & Ffound)
nf->ptr = (nf->ptr & ~Ffound) | Fignore;
ndbsetmalloctag(t, getcallerpc(&db));
return t;
}
static int
prefixlen(uchar *ip)
{
int y, i;
for(y = IPaddrlen-1; y >= 0; y--)
for(i = 8; i > 0; i--)
if(ip[y] & (1<<(8-i)))
return y*8 + i;
return 0;
}
/*
* look through a containing subset
*/
static Ndbtuple*
subnet(Ndb *db, uchar *net, Ndbtuple *f, int prefix)
{
Ndbs s;
char netstr[64];
uchar mask[IPaddrlen];
Ndbtuple *t, *nt, *xt;
t = nil;
snprint(netstr, sizeof(netstr), "%I", net);
nt = ndbsearch(db, &s, "ip", netstr);
while(nt != nil){
xt = ndbfindattr(nt, nt, "ipnet");
if(xt != nil){
xt = ndbfindattr(nt, nt, "ipmask");
if(xt == nil || parseipmask(mask, xt->val, isv4(net)) == -1)
ipmove(mask, defmask(net));
if(prefixlen(mask) <= prefix){
t = ndbconcatenate(t, filter(db, nt, f));
nt = nil;
}
}
ndbfree(nt);
nt = ndbsnext(&s, "ip", netstr);
}
ndbsetmalloctag(t, getcallerpc(&db));
return t;
}
static Ndbtuple*
netinfo(Ndb *db, Ndbtuple *t, char **alist, int n)
{
uchar ip[IPaddrlen], net[IPaddrlen];
int prefix, smallestprefix, force;
Ndbtuple *f, *nt;
nt = ndbfindattr(t, t, "ip");
if(nt == nil || parseip(ip, nt->val) == -1){
ndbfree(t);
return nil;
}
/* get needed attributes */
f = mkfilter(n, alist);
t = filter(db, t, f);
/*
* now go through subnets to fill in any missing attributes
*/
ipmove(net, ip);
if(isv4(ip)){
prefix = 127;
smallestprefix = 100;
force = 0;
} else {
/* in v6, the last 8 bytes have no structure (we hope) */
prefix = 64;
smallestprefix = 2;
memset(net+8, 0, 8);
force = 1;
}
/*
* to find a containing network, keep turning off
* the lower bit and look for a network with
* that address and a shorter mask. tedius but
* complete, we may need to find a trick to speed this up.
*/
for(; prefix >= smallestprefix; prefix--){
if(filtercomplete(f))
break;
if(!force && (net[prefix/8] & (1<<(7-(prefix%8)))) == 0)
continue;
force = 0;
net[prefix/8] &= ~(1<<(7-(prefix%8)));
t = ndbconcatenate(t, subnet(db, net, f, prefix));
}
/*
* if there's an unfulfilled ipmask, make one up
*/
nt = ndbfindattr(f, f, "ipmask");
if(nt != nil && !(nt->ptr & Fignore)){
char x[64];
snprint(x, sizeof(x), "%M", defmask(ip));
nt = ndbnew("ipmask", x);
nt->line = nt;
nt->entry = nil;
t = ndbconcatenate(t, nt);
}
ndbfree(f);
ndbsetmalloctag(t, getcallerpc(&db));
return t;
}
/*
* fill in all the requested attributes for a system.
* if the system's entry doesn't have all required,
* walk through successively more inclusive networks
* for inherited attributes.
*/
Ndbtuple*
ndbipinfo(Ndb *db, char *attr, char *val, char **alist, int n)
{
Ndbtuple *t, *nt;
char *ipstr;
Ndbs s;
/* just in case */
fmtinstall('I', eipfmt);
fmtinstall('M', eipfmt);
/*
* first look for a matching entry with an ip address
*/
ipstr = ndbgetvalue(db, &s, attr, val, "ip", &nt);
if(ipstr == nil){
/* none found, make one up */
if(strcmp(attr, "ip") != 0)
return nil;
nt = ndbnew("ip", val);
nt->line = nt;
nt->entry = nil;
t = netinfo(db, nt, alist, n);
} else {
/* found one */
free(ipstr);
t = nil;
do {
nt = ndbreorder(nt, s.t);
t = ndbconcatenate(t, netinfo(db, nt, alist, n));
} while((nt = ndbsnext(&s, attr, val)) != nil);
}
return ndbdedup(t);
}