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- #include <u.h>
- #include <libc.h>
- #include <auth.h>
- #include <fcall.h>
- #include <bio.h>
- #include <ctype.h>
- #include <ip.h>
- #include <pool.h>
- #include "dns.h"
- enum
- {
- Maxrequest= 1024,
- Maxreply= 8192, /* was 512 */
- Maxrrr= 32, /* was 16 */
- Maxfdata= 8192,
- Defmaxage= 60*60, /* tunable; was 1 then 3 hrs */
- Qdir= 0,
- Qdns= 1,
- };
- typedef struct Mfile Mfile;
- typedef struct Job Job;
- typedef struct Network Network;
- int vers; /* incremented each clone/attach */
- struct Mfile
- {
- Mfile *next; /* next free mfile */
- int ref;
- char *user;
- Qid qid;
- int fid;
- int type; /* reply type */
- char reply[Maxreply];
- ushort rr[Maxrrr]; /* offset of rr's */
- ushort nrr; /* number of rr's */
- };
- /*
- * active local requests
- */
- struct Job
- {
- Job *next;
- int flushed;
- Fcall request;
- Fcall reply;
- };
- Lock joblock;
- Job *joblist;
- struct {
- Lock;
- Mfile *inuse; /* active mfile's */
- } mfalloc;
- Cfg cfg;
- int debug;
- uchar ipaddr[IPaddrlen]; /* my ip address */
- int maxage = Defmaxage;
- int mfd[2];
- int needrefresh;
- ulong now;
- int sendnotifies;
- int testing;
- char *trace;
- int traceactivity;
- char *zonerefreshprogram;
- char *logfile = "dns"; /* or "dns.test" */
- char *dbfile;
- char mntpt[Maxpath];
- int fillreply(Mfile*, int);
- void freejob(Job*);
- void io(void);
- void mountinit(char*, char*);
- Job* newjob(void);
- void rattach(Job*, Mfile*);
- void rauth(Job*);
- void rclunk(Job*, Mfile*);
- void rcreate(Job*, Mfile*);
- void rflush(Job*);
- void ropen(Job*, Mfile*);
- void rread(Job*, Mfile*);
- void rremove(Job*, Mfile*);
- void rstat(Job*, Mfile*);
- void rversion(Job*);
- char* rwalk(Job*, Mfile*);
- void rwrite(Job*, Mfile*, Request*);
- void rwstat(Job*, Mfile*);
- void sendmsg(Job*, char*);
- void setext(char*, int, char*);
- void
- usage(void)
- {
- fprint(2, "usage: %s [-norRst] [-a maxage] [-f ndb-file] [-N target] "
- "[-x netmtpt] [-z refreshprog]\n", argv0);
- exits("usage");
- }
- void
- main(int argc, char *argv[])
- {
- char servefile[Maxpath], ext[Maxpath];
- setnetmtpt(mntpt, sizeof mntpt, nil);
- ext[0] = 0;
- ARGBEGIN{
- case 'a':
- maxage = atol(EARGF(usage()));
- if (maxage <= 0)
- maxage = Defmaxage;
- break;
- case 'd':
- debug = 1;
- traceactivity = 1;
- break;
- case 'f':
- dbfile = EARGF(usage());
- break;
- case 'n':
- sendnotifies = 1;
- break;
- case 'N':
- target = atol(EARGF(usage()));
- if (target < 100)
- target = 100;
- break;
- case 'o':
- cfg.straddle = 1; /* straddle inside & outside networks */
- break;
- case 'r':
- cfg.resolver = 1;
- break;
- case 'R':
- norecursion = 1;
- break;
- case 's':
- cfg.serve = 1; /* serve network */
- cfg.cachedb = 1;
- break;
- case 't':
- testing = 1;
- break;
- case 'x':
- setnetmtpt(mntpt, sizeof mntpt, EARGF(usage()));
- setext(ext, sizeof ext, mntpt);
- break;
- case 'z':
- zonerefreshprogram = EARGF(usage());
- break;
- }ARGEND
- USED(argc);
- USED(argv);
- if(testing)
- mainmem->flags |= POOL_NOREUSE | POOL_ANTAGONISM;
- // mainmem->flags |= POOL_ANTAGONISM;
- rfork(RFREND|RFNOTEG);
- cfg.inside = (*mntpt == '\0' || strcmp(mntpt, "/net") == 0);
- /* start syslog before we fork */
- fmtinstall('F', fcallfmt);
- dninit();
- /* this really shouldn't be fatal */
- if(myipaddr(ipaddr, mntpt) < 0)
- sysfatal("can't read my ip address");
- dnslog("starting %s%sdns %s%son %I's %s",
- (cfg.straddle? "straddling ": ""),
- (cfg.cachedb? "caching ": ""),
- (cfg.serve? "udp server ": ""),
- (cfg.resolver? "resolver ": ""), ipaddr, mntpt);
- opendatabase();
- snprint(servefile, sizeof servefile, "#s/dns%s", ext);
- unmount(servefile, mntpt);
- remove(servefile);
- mountinit(servefile, mntpt);
- now = time(nil);
- srand(now*getpid());
- db2cache(1);
- if (cfg.straddle && !seerootns())
- dnslog("straddle server misconfigured; can't see root name servers");
- if(cfg.serve)
- dnudpserver(mntpt);
- if(sendnotifies)
- notifyproc();
- io();
- dnslog("io returned, exiting");
- exits(0);
- }
- /*
- * if a mount point is specified, set the cs extension to be the mount point
- * with '_'s replacing '/'s
- */
- void
- setext(char *ext, int n, char *p)
- {
- int i, c;
- n--;
- for(i = 0; i < n; i++){
- c = p[i];
- if(c == 0)
- break;
- if(c == '/')
- c = '_';
- ext[i] = c;
- }
- ext[i] = 0;
- }
- void
- mountinit(char *service, char *mntpt)
- {
- int f;
- int p[2];
- char buf[32];
- if(pipe(p) < 0)
- abort(); /* "pipe failed" */;
- switch(rfork(RFFDG|RFPROC|RFNAMEG)){
- case 0:
- close(p[1]);
- procsetname("main");
- break;
- case -1:
- abort(); /* "fork failed\n" */;
- default:
- close(p[0]);
- /*
- * make a /srv/dns
- */
- f = create(service, 1, 0666);
- if(f < 0)
- abort(); /* service */;
- snprint(buf, sizeof buf, "%d", p[1]);
- if(write(f, buf, strlen(buf)) != strlen(buf))
- abort(); /* "write %s", service */;
- close(f);
- /*
- * put ourselves into the file system
- */
- if(mount(p[1], -1, mntpt, MAFTER, "") < 0)
- fprint(2, "dns mount failed: %r\n");
- _exits(0);
- }
- mfd[0] = mfd[1] = p[0];
- }
- Mfile*
- newfid(int fid, int needunused)
- {
- Mfile *mf;
- lock(&mfalloc);
- for(mf = mfalloc.inuse; mf != nil; mf = mf->next)
- if(mf->fid == fid){
- unlock(&mfalloc);
- if(needunused)
- return nil;
- return mf;
- }
- mf = emalloc(sizeof(*mf));
- if(mf == nil)
- sysfatal("out of memory");
- mf->fid = fid;
- mf->next = mfalloc.inuse;
- mfalloc.inuse = mf;
- unlock(&mfalloc);
- return mf;
- }
- void
- freefid(Mfile *mf)
- {
- Mfile **l;
- lock(&mfalloc);
- for(l = &mfalloc.inuse; *l != nil; l = &(*l)->next)
- if(*l == mf){
- *l = mf->next;
- if(mf->user)
- free(mf->user);
- memset(mf, 0, sizeof *mf); /* cause trouble */
- free(mf);
- unlock(&mfalloc);
- return;
- }
- sysfatal("freeing unused fid");
- }
- Mfile*
- copyfid(Mfile *mf, int fid)
- {
- Mfile *nmf;
- nmf = newfid(fid, 1);
- if(nmf == nil)
- return nil;
- nmf->fid = fid;
- nmf->user = estrdup(mf->user);
- nmf->qid.type = mf->qid.type;
- nmf->qid.path = mf->qid.path;
- nmf->qid.vers = vers++;
- return nmf;
- }
- Job*
- newjob(void)
- {
- Job *job;
- job = emalloc(sizeof *job);
- lock(&joblock);
- job->next = joblist;
- joblist = job;
- job->request.tag = -1;
- unlock(&joblock);
- return job;
- }
- void
- freejob(Job *job)
- {
- Job **l;
- lock(&joblock);
- for(l = &joblist; *l; l = &(*l)->next)
- if(*l == job){
- *l = job->next;
- memset(job, 0, sizeof *job); /* cause trouble */
- free(job);
- break;
- }
- unlock(&joblock);
- }
- void
- flushjob(int tag)
- {
- Job *job;
- lock(&joblock);
- for(job = joblist; job; job = job->next)
- if(job->request.tag == tag && job->request.type != Tflush){
- job->flushed = 1;
- break;
- }
- unlock(&joblock);
- }
- void
- io(void)
- {
- long n;
- Mfile *mf;
- uchar mdata[IOHDRSZ + Maxfdata];
- Request req;
- Job *job;
- memset(&req, 0, sizeof req);
- /*
- * a slave process is sometimes forked to wait for replies from other
- * servers. The master process returns immediately via a longjmp
- * through 'mret'.
- */
- if(setjmp(req.mret))
- putactivity(0);
- procsetname("main 9p reading loop");
- req.isslave = 0;
- for(;;){
- n = read9pmsg(mfd[0], mdata, sizeof mdata);
- if(n<=0){
- dnslog("error reading mntpt: %r");
- exits(0);
- }
- job = newjob();
- if(convM2S(mdata, n, &job->request) != n){
- freejob(job);
- continue;
- }
- mf = newfid(job->request.fid, 0);
- if(debug)
- dnslog("%F", &job->request);
- getactivity(&req, 0);
- req.aborttime = now + Maxreqtm;
- switch(job->request.type){
- default:
- warning("unknown request type %d", job->request.type);
- break;
- case Tversion:
- rversion(job);
- break;
- case Tauth:
- rauth(job);
- break;
- case Tflush:
- rflush(job);
- break;
- case Tattach:
- rattach(job, mf);
- break;
- case Twalk:
- rwalk(job, mf);
- break;
- case Topen:
- ropen(job, mf);
- break;
- case Tcreate:
- rcreate(job, mf);
- break;
- case Tread:
- rread(job, mf);
- break;
- case Twrite:
- rwrite(job, mf, &req);
- break;
- case Tclunk:
- rclunk(job, mf);
- break;
- case Tremove:
- rremove(job, mf);
- break;
- case Tstat:
- rstat(job, mf);
- break;
- case Twstat:
- rwstat(job, mf);
- break;
- }
- freejob(job);
- /*
- * slave processes die after replying
- */
- if(req.isslave){
- putactivity(0);
- _exits(0);
- }
- putactivity(0);
- }
- }
- void
- rversion(Job *job)
- {
- if(job->request.msize > IOHDRSZ + Maxfdata)
- job->reply.msize = IOHDRSZ + Maxfdata;
- else
- job->reply.msize = job->request.msize;
- if(strncmp(job->request.version, "9P2000", 6) != 0)
- sendmsg(job, "unknown 9P version");
- else{
- job->reply.version = "9P2000";
- sendmsg(job, 0);
- }
- }
- void
- rauth(Job *job)
- {
- sendmsg(job, "dns: authentication not required");
- }
- /*
- * don't flush till all the slaves are done
- */
- void
- rflush(Job *job)
- {
- flushjob(job->request.oldtag);
- sendmsg(job, 0);
- }
- void
- rattach(Job *job, Mfile *mf)
- {
- if(mf->user != nil)
- free(mf->user);
- mf->user = estrdup(job->request.uname);
- mf->qid.vers = vers++;
- mf->qid.type = QTDIR;
- mf->qid.path = 0LL;
- job->reply.qid = mf->qid;
- sendmsg(job, 0);
- }
- char*
- rwalk(Job *job, Mfile *mf)
- {
- int i, nelems;
- char *err;
- char **elems;
- Mfile *nmf;
- Qid qid;
- err = 0;
- nmf = nil;
- elems = job->request.wname;
- nelems = job->request.nwname;
- job->reply.nwqid = 0;
- if(job->request.newfid != job->request.fid){
- /* clone fid */
- nmf = copyfid(mf, job->request.newfid);
- if(nmf == nil){
- err = "clone bad newfid";
- goto send;
- }
- mf = nmf;
- }
- /* else nmf will be nil */
- qid = mf->qid;
- if(nelems > 0)
- /* walk fid */
- for(i=0; i<nelems && i<MAXWELEM; i++){
- if((qid.type & QTDIR) == 0){
- err = "not a directory";
- break;
- }
- if (strcmp(elems[i], "..") == 0 ||
- strcmp(elems[i], ".") == 0){
- qid.type = QTDIR;
- qid.path = Qdir;
- Found:
- job->reply.wqid[i] = qid;
- job->reply.nwqid++;
- continue;
- }
- if(strcmp(elems[i], "dns") == 0){
- qid.type = QTFILE;
- qid.path = Qdns;
- goto Found;
- }
- err = "file does not exist";
- break;
- }
- send:
- if(nmf != nil && (err!=nil || job->reply.nwqid<nelems))
- freefid(nmf);
- if(err == nil)
- mf->qid = qid;
- sendmsg(job, err);
- return err;
- }
- void
- ropen(Job *job, Mfile *mf)
- {
- int mode;
- char *err;
- err = 0;
- mode = job->request.mode;
- if(mf->qid.type & QTDIR)
- if(mode)
- err = "permission denied";
- job->reply.qid = mf->qid;
- job->reply.iounit = 0;
- sendmsg(job, err);
- }
- void
- rcreate(Job *job, Mfile *mf)
- {
- USED(mf);
- sendmsg(job, "creation permission denied");
- }
- void
- rread(Job *job, Mfile *mf)
- {
- int i, n;
- long clock;
- ulong cnt;
- vlong off;
- char *err;
- uchar buf[Maxfdata];
- Dir dir;
- n = 0;
- err = nil;
- off = job->request.offset;
- cnt = job->request.count;
- *buf = '\0';
- job->reply.data = (char*)buf;
- if(mf->qid.type & QTDIR){
- clock = time(nil);
- if(off == 0){
- dir.name = "dns";
- dir.qid.type = QTFILE;
- dir.qid.vers = vers;
- dir.qid.path = Qdns;
- dir.mode = 0666;
- dir.length = 0;
- dir.uid = dir.gid = dir.muid = mf->user;
- dir.atime = dir.mtime = clock; /* wrong */
- n = convD2M(&dir, buf, sizeof buf);
- }
- } else if (off < 0)
- err = "negative read offset";
- else {
- /* first offset will always be zero */
- for(i = 1; i <= mf->nrr; i++)
- if(mf->rr[i] > off)
- break;
- if(i <= mf->nrr) {
- if(off + cnt > mf->rr[i])
- n = mf->rr[i] - off;
- else
- n = cnt;
- assert(n >= 0);
- job->reply.data = mf->reply + off;
- }
- }
- job->reply.count = n;
- sendmsg(job, err);
- }
- void
- rwrite(Job *job, Mfile *mf, Request *req)
- {
- int rooted, status, wantsav;
- long n;
- ulong cnt;
- char *err, *p, *atype;
- RR *rp, *tp, *neg;
- err = nil;
- cnt = job->request.count;
- if(mf->qid.type & QTDIR){
- err = "can't write directory";
- goto send;
- }
- if (job->request.offset != 0) {
- err = "writing at non-zero offset";
- goto send;
- }
- if(cnt >= Maxrequest){
- err = "request too long";
- goto send;
- }
- job->request.data[cnt] = 0;
- if(cnt > 0 && job->request.data[cnt-1] == '\n')
- job->request.data[cnt-1] = 0;
- /*
- * special commands
- */
- if(strcmp(job->request.data, "debug")==0){
- debug ^= 1;
- goto send;
- } else if(strcmp(job->request.data, "dump")==0){
- dndump("/lib/ndb/dnsdump");
- goto send;
- } else if(strcmp(job->request.data, "refresh")==0){
- needrefresh = 1;
- goto send;
- } else if(strcmp(job->request.data, "poolcheck")==0){
- poolcheck(mainmem);
- goto send;
- }
- /*
- * kill previous reply
- */
- mf->nrr = 0;
- mf->rr[0] = 0;
- /*
- * break up request (into a name and a type)
- */
- atype = strchr(job->request.data, ' ');
- if(atype == 0){
- err = "illegal request";
- goto send;
- } else
- *atype++ = 0;
- /*
- * tracing request
- */
- if(strcmp(atype, "trace") == 0){
- if(trace)
- free(trace);
- if(*job->request.data)
- trace = estrdup(job->request.data);
- else
- trace = 0;
- goto send;
- }
- /* normal request: domain [type] */
- mf->type = rrtype(atype);
- if(mf->type < 0){
- err = "unknown type";
- goto send;
- }
- p = atype - 2;
- if(p >= job->request.data && *p == '.'){
- rooted = 1;
- *p = 0;
- } else
- rooted = 0;
- p = job->request.data;
- if(*p == '!'){
- wantsav = 1;
- p++;
- } else
- wantsav = 0;
- dncheck(0, 1);
- status = 0;
- rp = dnresolve(p, Cin, mf->type, req, 0, 0, Recurse, rooted, &status);
- dncheck(0, 1);
- neg = rrremneg(&rp);
- if(neg){
- status = neg->negrcode;
- rrfreelist(neg);
- }
- if(rp == nil)
- switch(status){
- case Rname:
- err = "name does not exist";
- break;
- case Rserver:
- err = "dns failure";
- break;
- default:
- err = "resource does not exist";
- break;
- }
- else {
- lock(&joblock);
- if(!job->flushed){
- /* format data to be read later */
- n = 0;
- mf->nrr = 0;
- for(tp = rp; mf->nrr < Maxrrr-1 && n < Maxreply && tp &&
- tsame(mf->type, tp->type); tp = tp->next){
- mf->rr[mf->nrr++] = n;
- if(wantsav)
- n += snprint(mf->reply+n, Maxreply-n,
- "%Q", tp);
- else
- n += snprint(mf->reply+n, Maxreply-n,
- "%R", tp);
- }
- mf->rr[mf->nrr] = n;
- }
- unlock(&joblock);
- rrfreelist(rp);
- }
- send:
- dncheck(0, 1);
- job->reply.count = cnt;
- sendmsg(job, err);
- }
- void
- rclunk(Job *job, Mfile *mf)
- {
- freefid(mf);
- sendmsg(job, 0);
- }
- void
- rremove(Job *job, Mfile *mf)
- {
- USED(mf);
- sendmsg(job, "remove permission denied");
- }
- void
- rstat(Job *job, Mfile *mf)
- {
- Dir dir;
- uchar buf[IOHDRSZ+Maxfdata];
- if(mf->qid.type & QTDIR){
- dir.name = ".";
- dir.mode = DMDIR|0555;
- } else {
- dir.name = "dns";
- dir.mode = 0666;
- }
- dir.qid = mf->qid;
- dir.length = 0;
- dir.uid = dir.gid = dir.muid = mf->user;
- dir.atime = dir.mtime = time(nil);
- job->reply.nstat = convD2M(&dir, buf, sizeof buf);
- job->reply.stat = buf;
- sendmsg(job, 0);
- }
- void
- rwstat(Job *job, Mfile *mf)
- {
- USED(mf);
- sendmsg(job, "wstat permission denied");
- }
- void
- sendmsg(Job *job, char *err)
- {
- int n;
- uchar mdata[IOHDRSZ + Maxfdata];
- char ename[ERRMAX];
- if(err){
- job->reply.type = Rerror;
- snprint(ename, sizeof ename, "dns: %s", err);
- job->reply.ename = ename;
- }else
- job->reply.type = job->request.type+1;
- job->reply.tag = job->request.tag;
- n = convS2M(&job->reply, mdata, sizeof mdata);
- if(n == 0){
- warning("sendmsg convS2M of %F returns 0", &job->reply);
- abort();
- }
- lock(&joblock);
- if(job->flushed == 0)
- if(write(mfd[1], mdata, n)!=n)
- sysfatal("mount write");
- unlock(&joblock);
- if(debug)
- dnslog("%F %d", &job->reply, n);
- }
- /*
- * the following varies between dnsdebug and dns
- */
- void
- logreply(int id, uchar *addr, DNSmsg *mp)
- {
- RR *rp;
- dnslog("%d: rcvd %I flags:%s%s%s%s%s", id, addr,
- mp->flags & Fauth? " auth": "",
- mp->flags & Ftrunc? " trunc": "",
- mp->flags & Frecurse? " rd": "",
- mp->flags & Fcanrec? " ra": "",
- (mp->flags & (Fauth|Rmask)) == (Fauth|Rname)? " nx": "");
- for(rp = mp->qd; rp != nil; rp = rp->next)
- dnslog("%d: rcvd %I qd %s", id, addr, rp->owner->name);
- for(rp = mp->an; rp != nil; rp = rp->next)
- dnslog("%d: rcvd %I an %R", id, addr, rp);
- for(rp = mp->ns; rp != nil; rp = rp->next)
- dnslog("%d: rcvd %I ns %R", id, addr, rp);
- for(rp = mp->ar; rp != nil; rp = rp->next)
- dnslog("%d: rcvd %I ar %R", id, addr, rp);
- }
- void
- logsend(int id, int subid, uchar *addr, char *sname, char *rname, int type)
- {
- char buf[12];
- dnslog("[%d] %d.%d: sending to %I/%s %s %s",
- getpid(), id, subid, addr, sname, rname,
- rrname(type, buf, sizeof buf));
- }
- RR*
- getdnsservers(int class)
- {
- return dnsservers(class);
- }
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