ref: 15d1425b276495a82621a8d075176a59a512cdf3
dir: /sys/src/cmd/ndb/dn.c/
#include <u.h> #include <libc.h> #include <ip.h> #include <ctype.h> #include "dns.h" /* * this comment used to say `our target is 4000 names cached, this should * be larger on large servers'. dns at Bell Labs starts off with * about 1780 names. */ enum { /* these settings will trigger frequent aging */ Deftarget = 4000, Defmaxage = 60*Min, /* default domain name max. age */ Defagefreq = 15*Min, /* age names this often (seconds) */ Minage = 1*Min, /* length of domain name hash table */ HTLEN = 4*1024, }; /* * Hash table for domain names. */ static DN *ht[HTLEN]; static struct { QLock; ulong names; /* names allocated */ ulong oldest; /* longest we'll leave a name around */ ulong lastage; /* time of lask dnageall() */ ushort id; /* same size as in packet */ uchar mark; /* current mark bit for gc */ int active[2]; /* number of active processes per mark */ } dnvars; /* names of RR types */ static char *rrnametab[] = { [Ta] "ip", [Tns] "ns", [Tmd] "md", [Tmf] "mf", [Tcname] "cname", [Tsoa] "soa", [Tmb] "mb", [Tmg] "mg", [Tmr] "mr", [Tnull] "null", [Twks] "wks", [Tptr] "ptr", [Thinfo] "hinfo", [Tminfo] "minfo", [Tmx] "mx", [Ttxt] "txt", [Trp] "rp", [Tafsdb] "afsdb", [Tx25] "x.25", [Tisdn] "isdn", [Trt] "rt", [Tnsap] "nsap", [Tnsapptr] "nsap-ptr", [Tsig] "sig", [Tkey] "key", [Tpx] "px", [Tgpos] "gpos", [Taaaa] "ipv6", [Tloc] "loc", [Tnxt] "nxt", [Teid] "eid", [Tnimloc] "nimrod", [Tsrv] "srv", [Tatma] "atma", [Tnaptr] "naptr", [Tkx] "kx", [Tcert] "cert", [Ta6] "a6", [Tdname] "dname", [Tsink] "sink", [Topt] "opt", [Tapl] "apl", [Tds] "ds", [Tsshfp] "sshfp", [Tipseckey] "ipseckey", [Trrsig] "rrsig", [Tnsec] "nsec", [Tdnskey] "dnskey", [Tspf] "spf", [Tuinfo] "uinfo", [Tuid] "uid", [Tgid] "gid", [Tunspec] "unspec", [Ttkey] "tkey", [Ttsig] "tsig", [Tixfr] "ixfr", [Taxfr] "axfr", [Tmailb] "mailb", [Tmaila] "maila", [Tall] "all", [Tcaa] "caa", }; /* names of response codes */ static char *rcnametab[] = { [Rok] "ok", [Rformat] "format error", [Rserver] "server failure", [Rname] "bad name", [Runimplimented] "unimplemented", [Rrefused] "we don't like you", [Ryxdomain] "name should not exist", [Ryxrrset] "rr set should not exist", [Rnxrrset] "rr set should exist", [Rnotauth] "not authorative", [Rnotzone] "not in zone", [Rbadvers] "bad opt version", /* [Rbadsig] "bad signature", */ [Rbadkey] "bad key", [Rbadtime] "bad signature time", [Rbadmode] "bad mode", [Rbadname] "duplicate key name", [Rbadalg] "bad algorithm", }; int maxage = Defmaxage; ulong target = Deftarget; int needrefresh; ulong now; uvlong nowms; static Lock dnlock; static ulong agefreq = Defagefreq; static int rrequiv(RR *r1, RR *r2); static void ding(void*, char *msg) { if(strstr(msg, "alarm") != nil) { noted(NCONT); /* resume with system call error */ } else noted(NDFLT); /* die */ } uvlong timems(void) { uvlong ms = nsec()/1000000L; now = ms/1000L; nowms = ms; return ms; } void dninit(void) { fmtinstall('E', eipfmt); fmtinstall('I', eipfmt); fmtinstall('V', eipfmt); fmtinstall('\\', bslashfmt); fmtinstall('R', rrfmt); fmtinstall('Q', rravfmt); fmtinstall('H', encodefmt); timems(); if (maxage <= 0) maxage = Defmaxage; dnvars.names = 0; dnvars.oldest = maxage; dnvars.lastage = now; dnvars.id = 0; dnvars.mark = 0; notify(ding); } /* * hash for a domain name */ static ulong dnhash(char *name) { ulong hash; uchar *val = (uchar*)name; for(hash = 0; *val; val++) hash = hash*13 + tolower(*val)-'a'; return hash % HTLEN; } /* * mark dn with current mark bit */ static void dnmark(DN *dp) { if(dp == nil) return; dp->mark = (dp->mark & ~1) | dnvars.mark; } /* * lookup a symbol. if enter is not zero and the name is * not found, create it. */ DN* dnlookup(char *name, int class, int enter) { DN **l; DN *dp; int n; l = &ht[dnhash(name)]; lock(&dnlock); for(dp = *l; dp; dp = dp->next) { if(dp->class == class && cistrcmp(dp->name, name) == 0) goto out; l = &dp->next; } if(!enter){ unlock(&dnlock); return nil; } dnvars.names++; n = strlen(name) + 1; dp = emalloc(sizeof(*dp) + n); memmove(dp->name, name, n); dp->class = class; dp->rr = nil; /* add new DN to tail of the hash list. *l points to last next ptr. */ dp->next = nil; *l = dp; out: dnmark(dp); unlock(&dnlock); return dp; } DN* idnlookup(char *name, int class, int enter) { char dom[Domlen]; if(utf2idn(name, dom, sizeof dom) >= 0) name = dom; return dnlookup(name, class, enter); } DN* ipalookup(uchar *ip, int class, int enter) { char addr[64]; snprint(addr, sizeof(addr), "%I", ip); return dnlookup(addr, class, enter); } static int rrsame(RR *rr1, RR *rr2) { return rr1 == rr2 || rr1 != nil && rr2 != nil && rr1->db == rr2->db && rr1->auth == rr2->auth && rrequiv(rr1, rr2); } static int rronlist(RR *rp, RR *lp) { for(; lp; lp = lp->next) if (rrsame(lp, rp)) return 1; return 0; } /* * purge all records */ void dnpurge(void) { DN *dp; RR *rp, *srp; int i; lock(&dnlock); for(i = 0; i < HTLEN; i++) for(dp = ht[i]; dp; dp = dp->next){ srp = rp = dp->rr; dp->rr = nil; for(; rp != nil; rp = rp->next) rp->cached = 0; rrfreelist(srp); } unlock(&dnlock); } /* * mark all refernced domain names of an RR. * call with dnlock held. */ static void rrmark(RR *rp) { dnmark(rp->owner); if(rp->negative){ dnmark(rp->negsoaowner); return; } switch(rp->type){ case Thinfo: dnmark(rp->cpu); dnmark(rp->os); break; case Ttxt: break; case Tcname: case Tmb: case Tmd: case Tmf: case Tns: case Tmx: case Tsrv: dnmark(rp->host); break; case Tmg: case Tmr: dnmark(rp->mb); break; case Tminfo: dnmark(rp->rmb); dnmark(rp->mb); break; case Trp: dnmark(rp->rmb); dnmark(rp->rp); break; case Ta: case Taaaa: dnmark(rp->ip); break; case Tptr: dnmark(rp->ptr); break; case Tsoa: dnmark(rp->host); dnmark(rp->rmb); break; case Tsig: dnmark(rp->sig->signer); break; case Tcaa: dnmark(rp->caa->tag); break; } } /* * delete head of *l and free the old head. * call with dnlock held. */ static void rrdelhead(RR **l) { RR *rp; rp = *l; if(rp == nil) return; *l = rp->next; /* unlink head */ rp->cached = 0; /* avoid blowing an assertion in rrfree */ rrfree(rp); } /* * check the age of resource records, * delete any that have timed out and * mark referenced domain names of the remaining records. * * note that db records are handled by dbagedb()/dnauthdb() * so they are ignored here. * * call with dnlock held. */ static void dnage(DN *dp) { RR **l, *rp; l = &dp->rr; while ((rp = *l) != nil){ assert(rp->cached); assert(rp->owner == dp); if(!rp->db && ((long)(rp->expire - now) <= 0 || (long)(now - (rp->expire - rp->ttl)) > dnvars.oldest)) rrdelhead(l); /* rp == *l before; *l == rp->next after */ else { l = &rp->next; rrmark(rp); } } } /* * periodicly sweep for old records and remove unreferenced domain names * * this is called once all activity ceased for the non-current * mark bit (previous cycle), meaning there are no more * unaccounted references to DN's with the non-current mark * from other activity slaves. * * this can run concurrently to current mark bit activity slaves * as DN's with current mark bit are not freed in this cycle, but * in the next cycle when the previously current mark bit activity * has ceased. */ void dnageall(int doit) { DN *dp, **l; int i; if(!doit){ ulong period; if(dnvars.names < target){ dnvars.oldest = maxage; return; } if(dnvars.names < target*2) { period = dnvars.oldest / 2; if(period > agefreq) period = agefreq; } else { period = Minage / 2; } if((long)(now - dnvars.lastage) < period) return; dnslog("more names (%lud) than target (%lud)", dnvars.names, target); dnvars.oldest /= 2; if(dnvars.oldest < Minage) dnvars.oldest = Minage; /* don't be silly */ } dnvars.lastage = now; lock(&dnlock); /* * delete all expired records and * mark referenced domain names * of the remaining records. */ for(i = 0; i < HTLEN; i++) for(dp = ht[i]; dp; dp = dp->next) dnage(dp); /* bump mark */ dnvars.mark ^= 1; assert(dnvars.active[dnvars.mark] == 0); /* sweep and remove unreferenced domain names */ for(i = 0; i < HTLEN; i++){ l = &ht[i]; for(dp = *l; dp; dp = *l){ if(dp->mark == dnvars.mark){ assert(dp->rr == nil); *l = dp->next; memset(dp, 0, sizeof *dp); /* cause trouble */ free(dp); dnvars.names--; continue; } l = &dp->next; } } unlock(&dnlock); } /* * timeout all database records (used when rereading db) */ void dnagedb(void) { DN *dp; int i; RR *rp; lock(&dnlock); for(i = 0; i < HTLEN; i++) for(dp = ht[i]; dp; dp = dp->next) { for(rp = dp->rr; rp; rp = rp->next) if(rp->db) rp->expire = 0; } unlock(&dnlock); } /* * mark all local db records about my area as authoritative, * delete timed out ones */ void dnauthdb(void) { int i; Area *area; DN *dp; RR *rp, **l; lock(&dnlock); for(i = 0; i < HTLEN; i++) for(dp = ht[i]; dp; dp = dp->next){ area = inmyarea(dp->name); l = &dp->rr; for(rp = *l; rp; rp = *l){ if(rp->db){ if(rp->expire == 0){ rrdelhead(l); continue; } if(area){ ulong minttl = area->soarr->soa->minttl; if(rp->ttl < minttl) rp->ttl = minttl; rp->auth = 1; } else if(rp->type == Tns && inmyarea(rp->host->name)) rp->auth = 1; } else if(area){ /* no outside spoofing */ rrdelhead(l); continue; } l = &rp->next; } } unlock(&dnlock); } /* * keep track of other processes to know if we can * garbage collect. block while garbage collecting. */ void getactivity(Request *req) { qlock(&dnvars); req->aux = nil; req->id = ++dnvars.id; req->mark = dnvars.mark; dnvars.active[req->mark]++; qunlock(&dnvars); } void putactivity(Request *req) { qlock(&dnvars); dnvars.active[req->mark]--; assert(dnvars.active[req->mark] >= 0); if(dnvars.active[dnvars.mark^1] == 0){ db2cache(needrefresh); dnageall(needrefresh); needrefresh = 0; } qunlock(&dnvars); } /* * Attach a single resource record to a domain name (new->owner). * - Avoid duplicates with already present RR's * - Chain all RR's of the same type adjacent to one another * - chain authoritative RR's ahead of non-authoritative ones * - remove any expired RR's * If new is a stale duplicate, rrfree it. * Must be called with dnlock held. */ static void rrattach1(RR *new, int auth) { RR **l; RR *rp; DN *dp; ulong ttl; assert(!new->cached); dp = new->owner; assert(dp != nil); new->auth |= auth; new->next = nil; /* * try not to let responses expire before we * can use them to complete this query, by extending * past (or nearly past) expiration time. */ if(new->db) ttl = Year; else ttl = new->ttl; if(ttl <= Min) ttl = 10*Min; new->expire = now + ttl; /* * find first rr of the right type */ l = &dp->rr; for(rp = *l; rp; rp = *l){ assert(rp->cached); assert(rp->owner == dp); if(rp->type == new->type) break; l = &rp->next; } /* * negative entries replace positive entries * positive entries replace negative entries * newer entries replace older entries with the same fields * * look farther ahead than just the next entry when looking * for duplicates; RRs of a given type can have different rdata * fields (e.g. multiple NS servers). */ while ((rp = *l) != nil){ assert(rp->cached); assert(rp->owner == dp); if(rp->type != new->type) break; if(rp->db == new->db && rp->auth == new->auth){ /* negative drives out positive and vice versa */ if(rp->negative != new->negative) { /* rp == *l before; *l == rp->next after */ rrdelhead(l); continue; } /* all things equal, pick the newer one */ else if(rrequiv(rp, new)){ /* old drives out new */ if((long)(rp->expire - new->expire) > 0) { rrfree(new); return; } /* rp == *l before; *l == rp->next after */ rrdelhead(l); continue; } /* * Hack for pointer records. This makes sure * the ordering in the list reflects the ordering * received or read from the database */ else if(rp->type == Tptr && !rp->negative && !new->negative && rp->ptr->ordinal > new->ptr->ordinal) break; } l = &rp->next; } if (rronlist(new, rp)) { /* should not happen; duplicates were processed above */ dnslog("adding duplicate %R to list of %R; aborting", new, rp); abort(); } /* * add to chain */ new->cached = 1; new->next = rp; *l = new; } /* * Attach a list of resource records to a domain name. * May rrfree any stale duplicate RRs; dismembers the list. * Upon return, every RR in the list will have been rrfree-d * or attached to its domain name. * See rrattach1 for properties preserved. */ void rrattach(RR *rp, int auth) { RR *next; lock(&dnlock); for(; rp; rp = next){ next = rp->next; rp->next = nil; if(rp->type == Tall || rp->type == Topt || !rrsupported(rp->type) || cfg.cachedb && !rp->db && inmyarea(rp->owner->name)) rrfree(rp); else rrattach1(rp, auth); } unlock(&dnlock); } RR** rrcopy(RR *rp, RR **last) { RR *nrp; SOA *soa; Srv *srv; Key *key; Caa *caa; Cert *cert; Sig *sig; Null *null; Txt *t, *nt, **l; nrp = rralloc(rp->type); switch(rp->type){ case Tsoa: soa = nrp->soa; *nrp = *rp; nrp->soa = soa; *soa = *rp->soa; soa->slaves = copyserverlist(rp->soa->slaves); break; case Tsrv: srv = nrp->srv; *nrp = *rp; nrp->srv = srv; *srv = *rp->srv; break; case Tdnskey: case Tkey: key = nrp->key; *nrp = *rp; nrp->key = key; *key = *rp->key; key->data = emalloc(key->dlen); memmove(key->data, rp->key->data, rp->key->dlen); break; case Tcaa: caa = nrp->caa; *nrp = *rp; nrp->caa = caa; *caa = *rp->caa; caa->data = emalloc(caa->dlen); memmove(caa->data, rp->caa->data, rp->caa->dlen); break; case Tcert: cert = nrp->cert; *nrp = *rp; nrp->cert = cert; *cert = *rp->cert; cert->data = emalloc(cert->dlen); memmove(cert->data, rp->cert->data, rp->cert->dlen); break; case Tsig: sig = nrp->sig; *nrp = *rp; nrp->sig = sig; *sig = *rp->sig; sig->data = emalloc(sig->dlen); memmove(sig->data, rp->sig->data, rp->sig->dlen); break; case Tnull: null = nrp->null; *nrp = *rp; nrp->null = null; *null = *rp->null; null->data = emalloc(null->dlen); memmove(null->data, rp->null->data, rp->null->dlen); break; case Ttxt: *nrp = *rp; l = &nrp->txt; *l = nil; for(t = rp->txt; t != nil; t = t->next){ nt = emalloc(sizeof(*nt)); nt->dlen = t->dlen; nt->data = emalloc(t->dlen); memmove(nt->data, t->data, t->dlen); nt->next = nil; *l = nt; l = &nt->next; } break; default: /* cache must only contain supported RR's */ assert(rrsupported(rp->type)); *nrp = *rp; break; } nrp->pc = getcallerpc(&rp); setmalloctag(nrp, nrp->pc); nrp->cached = 0; nrp->next = nil; rrmark(nrp); *last = nrp; return &nrp->next; } /* * lookup a resource record of a particular type and * class attached to a domain name. Return copies. * * Priority ordering is: * db authoritative * not timed out network authoritative * not timed out network unauthoritative * unauthoritative db * * if flag NOneg is set, don't return negative cached entries. * return nothing instead. */ RR* rrlookup(DN *dp, int type, int flag) { RR *rp, *first, **last; first = nil; last = &first; lock(&dnlock); /* try for an authoritative db entry */ for(rp = dp->rr; rp; rp = rp->next){ assert(rp->cached); if(rp->db) if(rp->auth) if(tsame(type, rp->type)) last = rrcopy(rp, last); } if(first) goto out; /* try for a living authoritative network entry */ for(rp = dp->rr; rp; rp = rp->next){ if(!rp->db) if(rp->auth) if((long)(rp->expire - now) > 0) if(tsame(type, rp->type)){ if(flag == NOneg && rp->negative) goto out; last = rrcopy(rp, last); } } if(first) goto out; /* try for a living unauthoritative network entry */ for(rp = dp->rr; rp; rp = rp->next){ if(!rp->db) if((long)(rp->expire - now) > 0) if(tsame(type, rp->type)){ if(flag == NOneg && rp->negative) goto out; last = rrcopy(rp, last); } } if(first) goto out; /* try for an unauthoritative db entry */ for(rp = dp->rr; rp; rp = rp->next){ if(rp->db) if(tsame(type, rp->type)) last = rrcopy(rp, last); } if(first) goto out; /* otherwise, settle for anything we got (except for negative caches) */ for(rp = dp->rr; rp; rp = rp->next) if(tsame(type, rp->type)){ if(rp->negative) goto out; last = rrcopy(rp, last); } out: unlock(&dnlock); unique(first); return first; } static int inzone(DN *dp, char *name, int namelen, int depth) { int n; for(n = 0; dp->name[n]; n++) if(dp->name[n] == '.') depth--; if(depth != 1 || n < namelen) return 0; if(cistrcmp(name, dp->name + n - namelen) != 0) return 0; if(n > namelen && dp->name[n - namelen - 1] != '.') return 0; return 1; } /* * return all resources (except SOA) of a zone. */ RR* rrgetzone(char *name) { int found, depth, h, n; RR *rp, *first, **l; DN *dp; for(n = 0, depth = 1; name[n]; n++) if(name[n] == '.') depth++; first = nil; l = &first; lock(&dnlock); do { found = 0; for(h = 0; h < HTLEN; h++) for(dp = ht[h]; dp; dp = dp->next) if(inzone(dp, name, n, depth)){ for(rp = dp->rr; rp; rp = rp->next){ /* * there shouldn't be negatives, * but just in case. * don't send any soa's, * ns's are enough. */ if (rp->negative || rp->type == Tsoa) continue; l = rrcopy(rp, l); } found = 1; } depth++; } while(found); unlock(&dnlock); return first; } /* * convert an ascii RR type name to its integer representation */ int rrtype(char *atype) { int i; for(i = 0; i < nelem(rrnametab); i++) if(rrnametab[i] && strcmp(rrnametab[i], atype) == 0) return i; /* make any a synonym for all */ if(strcmp(atype, "any") == 0) return Tall; else if(isascii(atype[0]) && isdigit(atype[0])) return atoi(atype); else return -1; } /* * return 0 if not a supported rr type */ int rrsupported(int type) { if(type < 0 || type >= nelem(rrnametab)) return 0; return rrnametab[type] != nil; } /* * compare 2 types */ int tsame(int t1, int t2) { return t1 == t2 || t1 == Tall; } /* * Add resource records to a list. */ RR* rrcat(RR **start, RR *rp) { RR *olp, *nlp; RR **last; /* check for duplicates */ for (olp = *start; 0 && olp; olp = olp->next) for (nlp = rp; nlp; nlp = nlp->next) if (rrsame(nlp, olp)) dnslog("rrcat: duplicate RR: %R", nlp); USED(olp); last = start; while(*last != nil) last = &(*last)->next; *last = rp; return *start; } RR* rrremfilter(RR **l, int (*filter)(RR*, void*), void *arg) { RR *first, *rp; RR **nl; first = nil; nl = &first; while(*l != nil){ rp = *l; if((*filter)(rp, arg)){ *l = rp->next; *nl = rp; nl = &rp->next; *nl = nil; } else l = &(*l)->next; } return first; } static int filterneg(RR *rp, void*) { return rp->negative; } static int filtertype(RR *rp, void *arg) { return rp->type == *((int*)arg); } static int filterowner(RR *rp, void *arg) { return rp->owner == (DN*)arg; } /* * remove negative cache rr's from an rr list */ RR* rrremneg(RR **l) { return rrremfilter(l, filterneg, nil); } /* * remove rr's of a particular type from an rr list */ RR* rrremtype(RR **l, int type) { return rrremfilter(l, filtertype, &type); } /* * remove rr's of a particular owner from an rr list */ RR* rrremowner(RR **l, DN *owner) { return rrremfilter(l, filterowner, owner); } static char * dnname(DN *dn) { return dn? dn->name: "<null>"; } static char * idnname(DN *dn, char *buf, int nbuf) { char *name; name = dnname(dn); if(idn2utf(name, buf, nbuf) >= 0) return buf; return name; } /* * txt rr strings can contain binary data such as * control characters and double quotes (") which would * collide with ndb(6) format. * escape special characters by encoding them as: \DDD * where D is a decimal digit. backslash (\) is escaped * by doubling. valid utf8 is encoded verbatim. */ int bslashfmt(Fmt *f) { int len, out, n, c; uchar *data; out = 0; len = f->prec; f->prec = 0; f->flags &= ~FmtPrec; data = va_arg(f->args, uchar*); for(; len > 0; data += n, len -= n){ if(*data >= Runeself && fullrune((char*)data, len)){ Rune r; n = chartorune(&r, (char*)data); if(r != Runeerror){ out += fmtprint(f, "%C", r); continue; } } c = *data; if(c < ' ' || c == '"' || c > '~') out += fmtprint(f, "\\%.3d", c); else if(c == '\\') out += fmtprint(f, "\\\\"); else out += fmtprint(f, "%c", c); n = 1; } return out; } /* * print conversion for rr records */ int rrfmt(Fmt *f) { int rv; char *strp, buf[Domlen]; Fmt fstr; RR *rp; Server *s; SOA *soa; Srv *srv; Txt *t; fmtstrinit(&fstr); rp = va_arg(f->args, RR*); if(rp == nil){ fmtprint(&fstr, "<null>"); goto out; } fmtprint(&fstr, "%s %s", dnname(rp->owner), rrname(rp->type, buf, sizeof buf)); if(rp->negative){ fmtprint(&fstr, "\tnegative - rcode %d %s", rp->negrcode, rcname(rp->negrcode)); goto out; } switch(rp->type){ case Thinfo: fmtprint(&fstr, "\t%s %s", dnname(rp->cpu), dnname(rp->os)); break; case Tcname: case Tmb: case Tmd: case Tmf: case Tns: fmtprint(&fstr, "\t%s", dnname(rp->host)); break; case Tmg: case Tmr: fmtprint(&fstr, "\t%s", dnname(rp->mb)); break; case Tminfo: fmtprint(&fstr, "\t%s %s", dnname(rp->mb), dnname(rp->rmb)); break; case Tmx: fmtprint(&fstr, "\t%lud %s", rp->pref, dnname(rp->host)); break; case Ta: case Taaaa: fmtprint(&fstr, "\t%s", dnname(rp->ip)); break; case Tptr: fmtprint(&fstr, "\t%s", dnname(rp->ptr)); break; case Tsoa: soa = rp->soa; fmtprint(&fstr, "\t%s %s %lud %lud %lud %lud %lud", dnname(rp->host), dnname(rp->rmb), (soa? soa->serial: 0), (soa? soa->refresh: 0), (soa? soa->retry: 0), (soa? soa->expire: 0), (soa? soa->minttl: 0)); if (soa) for(s = soa->slaves; s != nil; s = s->next) fmtprint(&fstr, " %s", s->name); break; case Tsrv: srv = rp->srv; fmtprint(&fstr, "\t%ud %ud %ud %s", (srv? srv->pri: 0), (srv? srv->weight: 0), rp->port, dnname(rp->host)); break; case Tnull: if (rp->null == nil) fmtprint(&fstr, "\t<null>"); else fmtprint(&fstr, "\t%.*H", rp->null->dlen, rp->null->data); break; case Ttxt: fmtprint(&fstr, "\t"); for(t = rp->txt; t != nil; t = t->next) fmtprint(&fstr, "%.*\\", t->dlen, t->data); break; case Trp: fmtprint(&fstr, "\t%s %s", dnname(rp->rmb), dnname(rp->rp)); break; case Tdnskey: case Tkey: if (rp->key == nil) fmtprint(&fstr, "\t<null> <null> <null>"); else fmtprint(&fstr, "\t%d %d %d", rp->key->flags, rp->key->proto, rp->key->alg); break; case Tsig: if (rp->sig == nil) fmtprint(&fstr, "\t<null> <null> <null> <null> <null> <null> <null> <null>"); else fmtprint(&fstr, "\t%d %d %d %lud %lud %lud %d %s", rp->sig->type, rp->sig->alg, rp->sig->labels, rp->sig->ttl, rp->sig->exp, rp->sig->incep, rp->sig->tag, dnname(rp->sig->signer)); break; case Tcert: if (rp->cert == nil) fmtprint(&fstr, "\t<null> <null> <null>"); else fmtprint(&fstr, "\t%d %d %d", rp->cert->type, rp->cert->tag, rp->cert->alg); break; case Tcaa: if (rp->caa == nil) fmtprint(&fstr, "\t<null> <null> <null>"); else fmtprint(&fstr, "\t%d %s %.*\\", rp->caa->flags, dnname(rp->caa->tag), rp->caa->dlen, rp->caa->data); break; case Topt: fmtprint(&fstr, "\t%#lux %d %.*H", rp->eflags, rp->udpsize, rp->opt->dlen, rp->opt->data); break; default: if(rrsupported(rp->type)) break; if (rp->unknown == nil) fmtprint(&fstr, "\t<null>"); else fmtprint(&fstr, "\t%.*H", rp->unknown->dlen, rp->unknown->data); } out: strp = fmtstrflush(&fstr); rv = fmtstrcpy(f, strp); free(strp); return rv; } /* * print conversion for rr records in attribute value form */ int rravfmt(Fmt *f) { int rv; char *strp, buf[Domlen]; Fmt fstr; RR *rp; Server *s; SOA *soa; Srv *srv; Txt *t; fmtstrinit(&fstr); rp = va_arg(f->args, RR*); if(rp == nil){ fmtprint(&fstr, "<null>"); goto out; } if(rp->type == Tptr) fmtprint(&fstr, "ptr=%s", dnname(rp->owner)); else fmtprint(&fstr, "dom=%s", idnname(rp->owner, buf, sizeof(buf))); switch(rp->type){ case Thinfo: fmtprint(&fstr, " cpu=%s os=%s", dnname(rp->cpu), dnname(rp->os)); break; case Tcname: fmtprint(&fstr, " cname=%s", idnname(rp->host, buf, sizeof(buf))); break; case Tmb: case Tmd: case Tmf: fmtprint(&fstr, " mbox=%s", idnname(rp->host, buf, sizeof(buf))); break; case Tns: fmtprint(&fstr, " ns=%s", idnname(rp->host, buf, sizeof(buf))); break; case Tmg: case Tmr: fmtprint(&fstr, " mbox=%s", idnname(rp->mb, buf, sizeof(buf))); break; case Tminfo: fmtprint(&fstr, " mbox=%s", idnname(rp->mb, buf, sizeof(buf))); fmtprint(&fstr, " mbox=%s", idnname(rp->rmb, buf, sizeof(buf))); break; case Tmx: fmtprint(&fstr, " pref=%lud mx=%s", rp->pref, idnname(rp->host, buf, sizeof(buf))); break; case Ta: case Taaaa: fmtprint(&fstr, " ip=%s", dnname(rp->ip)); break; case Tptr: fmtprint(&fstr, " dom=%s", idnname(rp->ptr, buf, sizeof(buf))); break; case Tsoa: soa = rp->soa; fmtprint(&fstr, " ns=%s", idnname(rp->host, buf, sizeof(buf))); fmtprint(&fstr, " mbox=%s", idnname(rp->rmb, buf, sizeof(buf))); fmtprint(&fstr, " serial=%lud refresh=%lud retry=%lud expire=%lud ttl=%lud", (soa? soa->serial: 0), (soa? soa->refresh: 0), (soa? soa->retry: 0), (soa? soa->expire: 0), (soa? soa->minttl: 0)); for(s = soa->slaves; s != nil; s = s->next) fmtprint(&fstr, " dnsslave=%s", s->name); break; case Tsrv: srv = rp->srv; fmtprint(&fstr, " pri=%ud weight=%ud port=%ud target=%s", (srv? srv->pri: 0), (srv? srv->weight: 0), rp->port, idnname(rp->host, buf, sizeof(buf))); break; case Tnull: if (rp->null == nil) fmtprint(&fstr, " null=<null>"); else fmtprint(&fstr, " null=%.*H", rp->null->dlen, rp->null->data); break; case Ttxt: fmtprint(&fstr, " txt=\""); for(t = rp->txt; t != nil; t = t->next) fmtprint(&fstr, "%.*\\", t->dlen, t->data); fmtprint(&fstr, "\""); break; case Trp: fmtprint(&fstr, " mbox=%s", idnname(rp->rmb, buf, sizeof(buf))); fmtprint(&fstr, " rp=%s", idnname(rp->rp, buf, sizeof(buf))); break; case Tdnskey: case Tkey: if (rp->key == nil) fmtprint(&fstr, " flags=<null> proto=<null> alg=<null>"); else fmtprint(&fstr, " flags=%d proto=%d alg=%d", rp->key->flags, rp->key->proto, rp->key->alg); break; case Tsig: if (rp->sig == nil) fmtprint(&fstr, " type=<null> alg=<null> labels=<null> ttl=<null> exp=<null> incep=<null> tag=<null> signer=<null>"); else fmtprint(&fstr, " type=%d alg=%d labels=%d ttl=%lud exp=%lud incep=%lud tag=%d signer=%s", rp->sig->type, rp->sig->alg, rp->sig->labels, rp->sig->ttl, rp->sig->exp, rp->sig->incep, rp->sig->tag, idnname(rp->sig->signer, buf, sizeof(buf))); break; case Tcert: if (rp->cert == nil) fmtprint(&fstr, " type=<null> tag=<null> alg=<null>"); else fmtprint(&fstr, " type=%d tag=%d alg=%d", rp->cert->type, rp->cert->tag, rp->cert->alg); break; case Tcaa: if (rp->caa == nil) fmtprint(&fstr, " flags=<null> tag=<null> caa=<null>"); else fmtprint(&fstr, " flags=%d tag=%s caa=\"%.*\\\"", rp->caa->flags, dnname(rp->caa->tag), rp->caa->dlen, rp->caa->data); break; default: if (rp->unknown == nil) fmtprint(&fstr, " type%d=<null>", rp->type); else fmtprint(&fstr, " type%d=%.*H", rp->type, rp->unknown->dlen, rp->unknown->data); } out: strp = fmtstrflush(&fstr); rv = fmtstrcpy(f, strp); free(strp); return rv; } void warning(char *fmt, ...) { char dnserr[256]; va_list arg; va_start(arg, fmt); vseprint(dnserr, dnserr+sizeof(dnserr), fmt, arg); va_end(arg); syslog(1, logfile, dnserr); /* on console too */ } void dnslog(char *fmt, ...) { char dnserr[256]; va_list arg; va_start(arg, fmt); vseprint(dnserr, dnserr+sizeof(dnserr), fmt, arg); va_end(arg); syslog(0, logfile, dnserr); } /* * create a slave process to handle a request to avoid one request blocking * another */ void slave(Request *req) { int ppid, procs; if(req->isslave) return; /* we're already a slave process */ procs = dnvars.active[0] + dnvars.active[1]; if(procs >= Maxactive){ dnslog("%d: [%d] too much activity", req->id, getpid()); return; } /* * parent returns to main loop, child does the work. * don't change note group. */ ppid = getpid(); switch(rfork(RFPROC|RFMEM|RFNOWAIT)){ case -1: break; case 0: procsetname("request slave of pid %d", ppid); /* * this relies on rfork producing separate, initially-identical * stacks, thus giving us two copies of `req', one in each * process. */ req->isslave = 1; break; default: if(++procs > stats.slavehiwat) stats.slavehiwat = procs; alarm(0); longjmp(req->mret, 1); } } static int blockequiv(Block *a, Block *b) { return a->dlen == b->dlen && memcmp(a->data, b->data, a->dlen) == 0; } static int keyequiv(Key *a, Key *b) { return a->flags == b->flags && a->proto == b->proto && a->alg == b->alg && blockequiv(a, b); } static int certequiv(Cert *a, Cert *b) { return a->type == a->type && a->tag == a->tag && a->alg == a->alg && blockequiv(a, b); } static int txtequiv(Txt *a, Txt *b) { uchar *ap, *ae, *bp, *be; int n; for(ap = ae = bp = be = nil;;ap += n, bp += n){ while(a != nil && (ap == nil || (ap >= ae && (a = a->next) != nil))) ap = a->data, ae = ap + a->dlen; while(b != nil && (bp == nil || (bp >= be && (b = b->next) != nil))) bp = b->data, be = bp + b->dlen; if(a == b || a == nil || b == nil) break; n = ae - ap; if(be - bp < n) n = be - bp; if(memcmp(ap, bp, n) != 0) return 0; } return a == b; } static int rrequiv(RR *r1, RR *r2) { if(r1->owner != r2->owner || r1->type != r2->type || r1->arg0 != r2->arg0 || r1->arg1 != r2->arg1) return 0; switch(r1->type){ case Tkey: return keyequiv(r1->key, r2->key); case Tcert: return certequiv(r1->cert, r2->cert); case Tsig: return r1->sig->signer == r2->sig->signer && certequiv(r1->sig, r2->sig); case Tnull: return blockequiv(r1->null, r2->null); case Ttxt: return txtequiv(r1->txt, r2->txt); case Tcaa: return r1->caa->flags == r2->caa->flags && r1->caa->tag == r2->caa->tag && blockequiv(r1->caa, r2->caa); default: if(!rrsupported(r1->type)) return 0; /* unknown never equal */ } return 1; } void unique(RR *rp) { RR **l, *nrp; for(; rp; rp = rp->next){ l = &rp->next; for(nrp = *l; nrp; nrp = *l) if(rrequiv(rp, nrp)){ *l = nrp->next; rrfree(nrp); } else l = &nrp->next; } } /* * true if second domain is subsumed by the first */ int subsume(char *higher, char *lower) { int hn, ln; ln = strlen(lower); hn = strlen(higher); if (ln < hn || cistrcmp(lower + ln - hn, higher) != 0 || ln > hn && hn != 0 && lower[ln - hn - 1] != '.') return 0; return 1; } /* * randomize the order we return items to provide some * load balancing for servers. * * only randomize the first class of entries */ RR* randomize(RR *rp) { RR *first, *last, *x, *base; ulong n; if(rp == nil || rp->next == nil) return rp; /* just randomize addresses, mx's and ns's */ for(x = rp; x; x = x->next) if(x->type != Ta && x->type != Taaaa && x->type != Tmx && x->type != Tns) return rp; base = rp; n = rand(); last = first = nil; while(rp != nil){ /* stop randomizing if we've moved past our class */ if(base->auth != rp->auth || base->db != rp->db){ last->next = rp; break; } /* unchain */ x = rp; rp = x->next; x->next = nil; if(n&1){ /* add to tail */ if(last == nil) first = x; else last->next = x; last = x; } else { /* add to head */ if(last == nil) last = x; x->next = first; first = x; } /* reroll the dice */ n >>= 1; } return first; } void* emalloc(int size) { char *x; x = mallocz(size, 1); if(x == nil) abort(); setmalloctag(x, getcallerpc(&size)); return x; } char* estrdup(char *s) { char *p; int n; n = strlen(s) + 1; p = mallocz(n, 0); if(p == nil) abort(); memmove(p, s, n); setmalloctag(p, getcallerpc(&s)); return p; } /* * create a pointer record */ static RR* mkptr(DN *dp, char *ptr, ulong ttl) { DN *ipdp; RR *rp; ipdp = dnlookup(ptr, Cin, 1); rp = rralloc(Tptr); rp->ptr = dp; rp->owner = ipdp; rp->db = 1; if(ttl) rp->ttl = ttl; return rp; } void bytes2nibbles(uchar *nibbles, uchar *bytes, int nbytes); /* * look for all ip addresses in this network and make * pointer records for them. */ void dnptr(uchar *net, uchar *mask, char *dom, int type, int subdoms, int ttl) { int i, j, len; char *p, *e; char ptr[Domlen]; uchar *ipp; uchar ip[IPaddrlen], nnet[IPaddrlen]; uchar nibip[IPaddrlen*2]; RR *rp, *first, **l; DN *dp; l = &first; first = nil; lock(&dnlock); for(i = 0; i < HTLEN; i++){ for(dp = ht[i]; dp; dp = dp->next){ for(rp = dp->rr; rp; rp = rp->next){ if(rp->type != type || rp->negative) continue; if(parseip(ip, rp->ip->name) == -1) continue; maskip(ip, mask, nnet); if(ipcmp(net, nnet) != 0) continue; l = rrcopy(rp, l); } } } unlock(&dnlock); for(rp = first; rp; rp = rp->next){ if(parseip(ip, rp->ip->name) == -1) continue; maskip(ip, mask, nnet); if(ipcmp(net, nnet) != 0) continue; ipp = ip; len = IPaddrlen; if (type == Taaaa) { bytes2nibbles(nibip, ip, IPaddrlen); ipp = nibip; len = 2*IPaddrlen; } p = ptr; e = ptr+sizeof(ptr); for(j = len - 1; j >= len - subdoms; j--) p = seprint(p, e, (type == Ta? "%d.": "%x."), ipp[j]); seprint(p, e, "%s", dom); rrattach(mkptr(rp->owner, ptr, ttl), Authoritative); } rrfreelist(first); } void addserver(Server **l, char *name) { Server *s; int n; while(*l) l = &(*l)->next; n = strlen(name) + 1; s = emalloc(sizeof(*s) + n); s->name = (char*)(s+1); memmove(s->name, name, n); s->next = nil; *l = s; } Server* copyserverlist(Server *s) { Server *ns; for(ns = nil; s != nil; s = s->next) addserver(&ns, s->name); return ns; } /* from here down is copied to ip/snoopy/dns.c periodically to update it */ /* * convert a integer response code to ascii name */ char* rcname(int rcode) { char *s; s = nil; if(rcode >= 0 && rcode < nelem(rcnametab)) s = rcnametab[rcode]; if(s==nil) s = ""; return s; } /* * convert an integer RR type to it's ascii name */ char* rrname(int type, char *buf, int len) { char *s; s = nil; if(type >= 0 && type < nelem(rrnametab)) s = rrnametab[type]; if(s==nil){ snprint(buf, len, "%d", type); s = buf; } return s; } /* * free a list of resource records and any related structs */ void rrfreelist(RR *rp) { RR *next; for(; rp; rp = next){ next = rp->next; rrfree(rp); } } void freeserverlist(Server *s) { Server *next; for(; s != nil; s = next){ next = s->next; memset(s, 0, sizeof *s); /* cause trouble */ free(s); } } /* * allocate a resource record of a given type */ RR* rralloc(int type) { RR *rp; assert((type & ~0xFFFF) == 0); rp = emalloc(sizeof(*rp)); rp->pc = getcallerpc(&type); rp->type = type; setmalloctag(rp, rp->pc); switch(type){ case Tsoa: rp->soa = emalloc(sizeof(*rp->soa)); rp->soa->slaves = nil; setmalloctag(rp->soa, rp->pc); break; case Tsrv: rp->srv = emalloc(sizeof(*rp->srv)); setmalloctag(rp->srv, rp->pc); break; case Tdnskey: case Tkey: rp->key = emalloc(sizeof(*rp->key)); setmalloctag(rp->key, rp->pc); break; case Tcaa: rp->caa = emalloc(sizeof(*rp->caa)); setmalloctag(rp->caa, rp->pc); break; case Tcert: rp->cert = emalloc(sizeof(*rp->cert)); setmalloctag(rp->cert, rp->pc); break; case Tsig: rp->sig = emalloc(sizeof(*rp->sig)); setmalloctag(rp->sig, rp->pc); break; case Tnull: rp->null = emalloc(sizeof(*rp->null)); setmalloctag(rp->null, rp->pc); break; case Topt: rp->opt = emalloc(sizeof(*rp->opt)); setmalloctag(rp->opt, rp->pc); break; default: if(rrsupported(type)) break; rp->unknown = emalloc(sizeof(*rp->unknown)); setmalloctag(rp->unknown, rp->pc); } rp->ttl = 0; rp->expire = 0; rp->next = nil; return rp; } /* * free a resource record and any related structs */ void rrfree(RR *rp) { Txt *t; assert(!rp->cached); switch(rp->type){ case Tsoa: freeserverlist(rp->soa->slaves); memset(rp->soa, 0, sizeof *rp->soa); /* cause trouble */ free(rp->soa); break; case Tsrv: memset(rp->srv, 0, sizeof *rp->srv); /* cause trouble */ free(rp->srv); break; case Tdnskey: case Tkey: free(rp->key->data); memset(rp->key, 0, sizeof *rp->key); /* cause trouble */ free(rp->key); break; case Tcert: free(rp->cert->data); memset(rp->cert, 0, sizeof *rp->cert); /* cause trouble */ free(rp->cert); break; case Tsig: free(rp->sig->data); memset(rp->sig, 0, sizeof *rp->sig); /* cause trouble */ free(rp->sig); break; case Tnull: free(rp->null->data); memset(rp->null, 0, sizeof *rp->null); /* cause trouble */ free(rp->null); break; case Tcaa: free(rp->caa->data); memset(rp->caa, 0, sizeof *rp->caa); /* cause trouble */ free(rp->caa); break; case Ttxt: while(t = rp->txt){ rp->txt = t->next; free(t->data); memset(t, 0, sizeof *t); /* cause trouble */ free(t); } break; case Topt: free(rp->opt->data); memset(rp->opt, 0, sizeof *rp->opt); /* cause trouble */ free(rp->opt); break; default: if(rrsupported(rp->type)) break; free(rp->unknown->data); memset(rp->unknown, 0, sizeof *rp->unknown); /* cause trouble */ free(rp->unknown); break; } memset(rp, 0, sizeof *rp); /* cause trouble */ free(rp); }