ref: 5e098228acee982a11484fc5f5b3d127a521dfdd
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 containing subsets */ static Ndbtuple* subnet(Ndb *db, uchar *net, Ndbtuple *f, int prefix) { Ndbs s; int nprefix; char netstr[64]; uchar mask[IPaddrlen]; Ndbtuple *at[128+1], *nt, *xt, *t; memset(at, 0, sizeof(at)); 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)); nprefix = prefixlen(mask); if(nprefix <= prefix && at[nprefix] == nil){ /* remember containing subnet, order by prefix length */ at[nprefix] = nt; nt = nil; } } ndbfree(nt); nt = ndbsnext(&s, "ip", netstr); } /* filter subnets, longest prefix first */ for(t = nil; prefix >= 0; prefix--){ if(at[prefix] != nil) t = ndbconcatenate(t, filter(db, at[prefix], f)); } 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); }