libndb: order subnets by prefix length for ndbipinfo() lookups
to reproduce: ipnet=foo0 ip=192.168.0.0 ipmask=/16 ipnet=foo1 ip=192.168.0.0 ipmask=/24 ip=192.168.0.1 sys=foo2 % ndb/ipquery sys foo2 ipnet ipmask ipnet=foo0 ipmask=/16 we would expect to get ipnet=foo1 here as it is more specific subnet. the solution is to order the subnets by prefix length in subnet() before calling filter(), so that we process the longest prefixes first.
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1 changed files with 13 additions and 5 deletions
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@ -114,17 +114,18 @@ prefixlen(uchar *ip)
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}
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/*
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* look through a containing subset
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* look through containing subsets
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*/
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static Ndbtuple*
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subnet(Ndb *db, uchar *net, Ndbtuple *f, int prefix)
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{
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Ndbs s;
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int nprefix;
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char netstr[64];
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uchar mask[IPaddrlen];
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Ndbtuple *t, *nt, *xt;
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Ndbtuple *at[128+1], *nt, *xt, *t;
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t = nil;
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memset(at, 0, sizeof(at));
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snprint(netstr, sizeof(netstr), "%I", net);
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nt = ndbsearch(db, &s, "ip", netstr);
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while(nt != nil){
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@ -133,14 +134,21 @@ subnet(Ndb *db, uchar *net, Ndbtuple *f, int prefix)
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xt = ndbfindattr(nt, nt, "ipmask");
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if(xt == nil || parseipmask(mask, xt->val, isv4(net)) == -1)
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ipmove(mask, defmask(net));
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if(prefixlen(mask) <= prefix){
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t = ndbconcatenate(t, filter(db, nt, f));
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nprefix = prefixlen(mask);
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if(nprefix <= prefix && at[nprefix] == nil){
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/* remember containing subnet, order by prefix length */
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at[nprefix] = nt;
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nt = nil;
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}
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}
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ndbfree(nt);
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nt = ndbsnext(&s, "ip", netstr);
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}
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/* filter subnets, longest prefix first */
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for(t = nil; prefix >= 0; prefix--){
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if(at[prefix] != nil)
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t = ndbconcatenate(t, filter(db, at[prefix], f));
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}
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ndbsetmalloctag(t, getcallerpc(&db));
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return t;
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}
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