static int dblchk(str *domain, str *dbltxt)
{
str dblstr;
char *dbl = getenv("DBLLOOKUP");
int l, i;
unsigned char ansbuf[512];
if(!dbl || domain->len == 0) return 0;
if(session_getnum("sump",0)) return 0; /* no point */
str_init(&dblstr);
str_copy(&dblstr, domain);
str_catc(&dblstr, '.');
str_cats(&dblstr, dbl);
l = res_query(dblstr.s, C_IN, T_TXT, ansbuf, sizeof(ansbuf));
if(l > 0 && ((HEADER *)ansbuf)->ancount != 0) { /* something in the answer */
unsigned char *recbuf = ansbuf+NS_HFIXEDSZ;
/* skip over questions, why am I still writing stuff
* like this? */
for(i = ns_get16(ansbuf+4); i != 0; --i)
recbuf += dn_skipname(recbuf, ansbuf+l)+4;
for(i = ns_get16(ansbuf+6); i != 0; --i) {
recbuf += dn_skipname(recbuf, ansbuf+l);
if(ns_get16(recbuf) != T_TXT) { /* CNAME or something */
recbuf += 10 + ns_get16(recbuf+8);
continue;
}
/* it's a TXT record, wow */
str_init(dbltxt);
str_copyb(dbltxt, (char*)recbuf+11, recbuf[10]);
str_free(&dblstr);
return 1;
}
} /* didn't find anything */
str_free(&dblstr);
return 0;
}
static int
app_parse_srv(radiodns_app_t *app, ns_msg handle, ns_rr rr, char *dnbuf, radiodns_srv_t *srv)
{
const unsigned char *rdata;
(void) app;
rdata = ns_rr_rdata(rr);
srv->priority = ns_get16(rdata);
rdata += NS_INT16SZ;
srv->weight = ns_get16(rdata);
rdata += NS_INT16SZ;
srv->port = ns_get16(rdata);
rdata += NS_INT16SZ;
dn_expand(ns_msg_base(handle), ns_msg_base(handle) + ns_msg_size(handle), rdata, dnbuf, MAXDNAME);
if(!(srv->target = strdup(dnbuf)))
{
return -2;
}
return 0;
}
u_int16_t _getshort(const u_char *src) { return (ns_get16(src)); }
static void afsdb_hosts_to_addrs(char *vllist[],
int *vlsnum,
ns_msg handle,
ns_sect section,
unsigned mask,
unsigned long *_ttl)
{
int rrnum;
ns_rr rr;
int subtype, i, ret;
unsigned int ttl = UINT_MAX, rr_ttl;
debug("AFSDB RR count is %d", ns_msg_count(handle, section));
/* Look at all the resource records in this section. */
for (rrnum = 0; rrnum < ns_msg_count(handle, section); rrnum++) {
/* Expand the resource record number rrnum into rr. */
if (ns_parserr(&handle, section, rrnum, &rr)) {
_error("ns_parserr failed : %m");
continue;
}
/* We're only interested in AFSDB records */
if (ns_rr_type(rr) == ns_t_afsdb) {
vllist[*vlsnum] = malloc(MAXDNAME);
if (!vllist[*vlsnum])
error("Out of memory");
subtype = ns_get16(ns_rr_rdata(rr));
/* Expand the name server's domain name */
if (ns_name_uncompress(ns_msg_base(handle),
ns_msg_end(handle),
ns_rr_rdata(rr) + 2,
vllist[*vlsnum],
MAXDNAME) < 0)
error("ns_name_uncompress failed");
rr_ttl = ns_rr_ttl(rr);
if (ttl > rr_ttl)
ttl = rr_ttl;
/* Check the domain name we've just unpacked and add it to
* the list of VL servers if it is not a duplicate.
* If it is a duplicate, just ignore it.
*/
for (i = 0; i < *vlsnum; i++)
if (strcasecmp(vllist[i], vllist[*vlsnum]) == 0)
goto next_one;
/* Turn the hostname into IP addresses */
ret = dns_resolver(vllist[*vlsnum], mask);
if (ret) {
debug("AFSDB RR can't resolve."
"subtype:%d, server name:%s, netmask:%u",
subtype, vllist[*vlsnum], mask);
goto next_one;
}
info("AFSDB RR subtype:%d, server name:%s, ip:%*.*s, ttl:%u",
subtype, vllist[*vlsnum],
(int)payload[payload_index - 1].iov_len,
(int)payload[payload_index - 1].iov_len,
(char *)payload[payload_index - 1].iov_base,
ttl);
/* prepare for the next record */
*vlsnum += 1;
continue;
next_one:
free(vllist[*vlsnum]);
}
}
*_ttl = ttl;
info("ttl: %u", ttl);
}
int
DnsResolver_lookupMx(DnsResolver *self, const char *domain, DnsMxResponse **resp)
{
int query_stat = DnsResolver_query(self, domain, ns_t_mx);
if (NETDB_SUCCESS != query_stat) {
return query_stat;
} // end if
size_t msg_count = ns_msg_count(self->msghanlde, ns_s_an);
DnsMxResponse *respobj =
(DnsMxResponse *) malloc(sizeof(DnsMxResponse) + msg_count * sizeof(struct mxentry *));
if (NULL == respobj) {
return DnsResolver_setError(self, NETDB_INTERNAL);
} // end if
memset(respobj, 0, sizeof(DnsMxResponse) + msg_count * sizeof(struct mxentry *));
respobj->num = 0;
for (size_t n = 0; n < msg_count; ++n) {
ns_rr rr;
int parse_stat = ns_parserr(&self->msghanlde, ns_s_an, n, &rr);
if (0 != parse_stat) {
goto formerr;
} // end if
if (ns_t_mx != ns_rr_type(rr)) {
continue;
} // end if
const unsigned char *rdata = ns_rr_rdata(rr);
if (ns_rr_rdlen(rr) < NS_INT16SZ) {
goto formerr;
} // end if
int preference = ns_get16(rdata);
rdata += NS_INT16SZ;
// NOTE: NS_MAXDNAME で十分なのかイマイチ確証が持てないが, bind8 の dig コマンドの実装でもこの値を使っていたのでいいのではないか.
char dnamebuf[NS_MAXDNAME];
int dnamelen =
ns_name_uncompress(self->msgbuf, self->msgbuf + self->msglen, rdata, dnamebuf,
sizeof(dnamebuf));
if (NS_INT16SZ + dnamelen != ns_rr_rdlen(rr)) {
goto formerr;
} // end if
// TODO: dnamebuf は NULL 終端が保証されているのか?
size_t domainlen = strlen(dnamebuf);
respobj->exchange[respobj->num] =
(struct mxentry *) malloc(sizeof(struct mxentry) + sizeof(char[domainlen + 1]));
if (NULL == respobj->exchange[respobj->num]) {
goto noresource;
} // end if
respobj->exchange[respobj->num]->preference = preference;
if (domainlen + 1 <=
strlcpy(respobj->exchange[respobj->num]->domain, dnamebuf, domainlen + 1)) {
abort();
} // end if
++(respobj->num);
} // end for
if (0 == respobj->num) {
goto formerr;
} // end if
*resp = respobj;
return NETDB_SUCCESS;
formerr:
DnsMxResponse_free(respobj);
return DnsResolver_setError(self, NO_RECOVERY);
noresource:
DnsMxResponse_free(respobj);
return DnsResolver_setError(self, NETDB_INTERNAL);
} // end function : DnsResolver_lookupMx
static int
printZone(ns_type xfr, const char *zone, const struct sockaddr_in *sin,
ns_tsig_key *key)
{
static u_char *answer = NULL;
static int answerLen = 0;
querybuf buf;
int msglen, amtToRead, numRead, result, sockFD, len;
int count, type, rlen, done, n;
int numAnswers, numRecords, soacnt;
u_char *cp, tmp[NS_INT16SZ];
char dname[2][NS_MAXDNAME];
enum { NO_ERRORS, ERR_READING_LEN, ERR_READING_MSG, ERR_PRINTING }
error;
pid_t zpid = -1;
u_char *newmsg;
int newmsglen;
ns_tcp_tsig_state tsig_state;
int tsig_ret, tsig_required, tsig_present;
switch (xfr) {
case ns_t_axfr:
case ns_t_zxfr:
break;
default:
fprintf(stderr, ";; %s - transfer type not supported\n",
p_type(xfr));
return (ERROR);
}
/*
* Create a query packet for the requested zone name.
*/
msglen = res_nmkquery(&res, ns_o_query, zone,
queryClass, ns_t_axfr, NULL,
0, 0, buf.qb2, sizeof buf);
if (msglen < 0) {
if (res.options & RES_DEBUG)
fprintf(stderr, ";; res_nmkquery failed\n");
return (ERROR);
}
/*
* Sign the message if a key was sent
*/
if (key == NULL) {
newmsg = (u_char *)&buf;
newmsglen = msglen;
} else {
DST_KEY *dstkey;
int bufsize, siglen;
u_char sig[64];
int ret;
/* ns_sign() also calls dst_init(), but there is no harm
* doing it twice
*/
dst_init();
bufsize = msglen + 1024;
newmsg = (u_char *) malloc(bufsize);
if (newmsg == NULL) {
errno = ENOMEM;
return (-1);
}
memcpy(newmsg, (u_char *)&buf, msglen);
newmsglen = msglen;
if (strcmp(key->alg, NS_TSIG_ALG_HMAC_MD5) != 0)
dstkey = NULL;
else
dstkey = dst_buffer_to_key(key->name, KEY_HMAC_MD5,
NS_KEY_TYPE_AUTH_ONLY,
NS_KEY_PROT_ANY,
key->data, key->len);
if (dstkey == NULL) {
errno = EINVAL;
if (key)
free(newmsg);
return (-1);
}
siglen = sizeof(sig);
/* newmsglen++; */
ret = ns_sign(newmsg, &newmsglen, bufsize, NOERROR, dstkey, NULL, 0,
sig, &siglen, 0);
if (ret < 0) {
if (key)
free (newmsg);
if (ret == NS_TSIG_ERROR_NO_SPACE)
errno = EMSGSIZE;
else if (ret == -1)
errno = EINVAL;
return (ret);
}
ns_verify_tcp_init(dstkey, sig, siglen, &tsig_state);
}
/*
* Set up a virtual circuit to the server.
*/
if ((sockFD = socket(sin->sin_family, SOCK_STREAM, 0)) < 0) {
int e = errno;
perror(";; socket");
return (e);
}
switch (sin->sin_family) {
case AF_INET:
if (bind(sockFD, (struct sockaddr *)&myaddress,
sizeof myaddress) < 0){
int e = errno;
fprintf(stderr, ";; bind(%s port %u): %s\n",
inet_ntoa(myaddress.sin_addr),
ntohs(myaddress.sin_port),
strerror(e));
(void) close(sockFD);
sockFD = -1;
return (e);
}
if (connect(sockFD, (const struct sockaddr *)sin,
sizeof *sin) < 0) {
int e = errno;
perror(";; connect");
(void) close(sockFD);
sockFD = -1;
return (e);
}
break;
case AF_INET6:
if (bind(sockFD, (struct sockaddr *)&myaddress6,
sizeof myaddress6) < 0){
int e = errno;
char buf[80];
fprintf(stderr, ";; bind(%s port %u): %s\n",
inet_ntop(AF_INET6, &myaddress6.sin6_addr,
buf, sizeof(buf)),
ntohs(myaddress6.sin6_port),
strerror(e));
(void) close(sockFD);
sockFD = -1;
return (e);
}
if (connect(sockFD, (const struct sockaddr *)sin,
sizeof(struct sockaddr_in6)) < 0) {
int e = errno;
perror(";; connect");
(void) close(sockFD);
sockFD = -1;
return (e);
}
break;
}
/*
* Send length & message for zone transfer
*/
ns_put16(newmsglen, tmp);
if (write(sockFD, (char *)tmp, NS_INT16SZ) != NS_INT16SZ ||
write(sockFD, (char *)newmsg, newmsglen) != newmsglen) {
int e = errno;
if (key)
free (newmsg);
perror(";; write");
(void) close(sockFD);
sockFD = -1;
return (e);
} else if (key)
free (newmsg);
/*
* If we're compressing, push a gzip into the pipeline.
*/
if (xfr == ns_t_zxfr) {
enum { rd = 0, wr = 1 };
int z[2];
if (pipe(z) < 0) {
int e = errno;
perror(";; pipe");
(void) close(sockFD);
sockFD = -1;
return (e);
}
zpid = vfork();
if (zpid < 0) {
int e = errno;
perror(";; fork");
(void) close(sockFD);
sockFD = -1;
return (e);
} else if (zpid == 0) {
/* Child. */
(void) close(z[rd]);
(void) dup2(sockFD, STDIN_FILENO);
(void) close(sockFD);
(void) dup2(z[wr], STDOUT_FILENO);
(void) close(z[wr]);
execlp("gzip", "gzip", "-d", "-v", NULL);
perror(";; child: execlp(gunzip)");
_exit(1);
}
/* Parent. */
(void) close(z[wr]);
(void) dup2(z[rd], sockFD);
(void) close(z[rd]);
}
result = 0;
numAnswers = 0;
numRecords = 0;
soacnt = 0;
error = NO_ERRORS;
numRead = 0;
dname[0][0] = '\0';
for (done = 0; !done; (void)NULL) {
/*
* Read the length of the response.
*/
cp = tmp;
amtToRead = INT16SZ;
while (amtToRead > 0 &&
(numRead = read(sockFD, cp, amtToRead)) > 0) {
cp += numRead;
amtToRead -= numRead;
}
if (numRead <= 0) {
error = ERR_READING_LEN;
break;
}
len = ns_get16(tmp);
if (len == 0)
break; /* nothing left to read */
/*
* The server sent too much data to fit the existing buffer --
* allocate a new one.
*/
if (len > answerLen) {
if (answerLen != 0)
free(answer);
answerLen = len;
answer = (u_char *)malloc(answerLen);
}
/*
* Read the response.
*/
amtToRead = len;
cp = answer;
while (amtToRead > 0 &&
(numRead = read(sockFD, cp, amtToRead)) > 0) {
cp += numRead;
amtToRead -= numRead;
}
if (numRead <= 0) {
error = ERR_READING_MSG;
break;
}
result = print_axfr(stdout, answer, len);
if (result != 0) {
error = ERR_PRINTING;
break;
}
numRecords += htons(((HEADER *)answer)->ancount);
numAnswers++;
/* Header. */
cp = answer + HFIXEDSZ;
/* Question. */
for (count = ntohs(((HEADER *)answer)->qdcount);
count > 0;
count--) {
n = dn_skipname(cp, answer + len);
if (n < 0) {
error = ERR_PRINTING;
done++;
break;
}
cp += n + QFIXEDSZ;
if (cp > answer + len) {
error = ERR_PRINTING;
done++;
break;
}
}
/* Answer. */
for (count = ntohs(((HEADER *)answer)->ancount);
count > 0 && !done;
count--) {
n = dn_expand(answer, answer + len, cp,
dname[soacnt], sizeof dname[0]);
if (n < 0) {
error = ERR_PRINTING;
done++;
break;
}
cp += n;
if (cp + 3 * INT16SZ + INT32SZ > answer + len) {
error = ERR_PRINTING;
done++;
break;
}
GETSHORT(type, cp);
cp += INT16SZ;
cp += INT32SZ; /* ttl */
GETSHORT(rlen, cp);
cp += rlen;
if (cp > answer + len) {
error = ERR_PRINTING;
done++;
break;
}
if (type == T_SOA && soacnt++ &&
ns_samename(dname[0], dname[1]) == 1) {
done++;
break;
}
}
/*
* Verify the TSIG
*/
if (key) {
if (ns_find_tsig(answer, answer + len) != NULL)
tsig_present = 1;
else
tsig_present = 0;
if (numAnswers == 1 || soacnt > 1)
tsig_required = 1;
else
tsig_required = 0;
tsig_ret = ns_verify_tcp(answer, &len, &tsig_state,
tsig_required);
if (tsig_ret == 0) {
if (tsig_present)
printf("; TSIG ok\n");
}
else
printf("; TSIG invalid\n");
}
}
printf(";; Received %d answer%s (%d record%s).\n",
numAnswers, (numAnswers != 1) ? "s" : "",
numRecords, (numRecords != 1) ? "s" : "");
(void) close(sockFD);
sockFD = -1;
/*
* If we were uncompressing, reap the uncompressor.
*/
if (xfr == ns_t_zxfr) {
pid_t pid;
int status = 0;
pid = wait(&status);
if (pid < 0) {
int e = errno;
perror(";; wait");
return (e);
}
if (pid != zpid) {
fprintf(stderr, ";; wrong pid (%lu != %lu)\n",
(u_long)pid, (u_long)zpid);
return (ERROR);
}
printf(";; pid %lu: exit %d, signal %d, core %c\n",
(u_long)pid, WEXITSTATUS(status),
WIFSIGNALED(status) ? WTERMSIG(status) : 0,
WCOREDUMP(status) ? 't' : 'f');
}
switch (error) {
case NO_ERRORS:
return (0);
case ERR_READING_LEN:
return (EMSGSIZE);
case ERR_PRINTING:
return (result);
case ERR_READING_MSG:
return (EMSGSIZE);
default:
return (EFAULT);
}
}
DNS::HostMap DNS::resolve( const std::string& service, const std::string& proto,
const std::string& domain, const LogSink& logInstance )
{
buffer srvbuf;
bool error = false;
const std::string dname = "_" + service + "._" + proto;
if( !domain.empty() )
srvbuf.len = res_querydomain( dname.c_str(), const_cast<char*>( domain.c_str() ),
C_IN, T_SRV, srvbuf.buf, NS_PACKETSZ );
else
srvbuf.len = res_query( dname.c_str(), C_IN, T_SRV, srvbuf.buf, NS_PACKETSZ );
if( srvbuf.len < 0 )
return defaultHostMap( domain, logInstance );
HEADER* hdr = (HEADER*)srvbuf.buf;
unsigned char* here = srvbuf.buf + NS_HFIXEDSZ;
if( ( hdr->tc ) || ( srvbuf.len < NS_HFIXEDSZ ) )
error = true;
if( hdr->rcode >= 1 && hdr->rcode <= 5 )
error = true;
if( ntohs( hdr->ancount ) == 0 )
error = true;
if( ntohs( hdr->ancount ) > NS_PACKETSZ )
error = true;
int cnt;
for( cnt = ntohs( hdr->qdcount ); cnt>0; --cnt )
{
int strlen = dn_skipname( here, srvbuf.buf + srvbuf.len );
here += strlen + NS_QFIXEDSZ;
}
unsigned char* srv[NS_PACKETSZ];
int srvnum = 0;
for( cnt = ntohs( hdr->ancount ); cnt>0; --cnt )
{
int strlen = dn_skipname( here, srvbuf.buf + srvbuf.len );
here += strlen;
srv[srvnum++] = here;
here += SRV_FIXEDSZ;
here += dn_skipname( here, srvbuf.buf + srvbuf.len );
}
if( error )
{
return defaultHostMap( domain, logInstance );
}
// (q)sort here
HostMap servers;
for( cnt=0; cnt<srvnum; ++cnt )
{
name srvname;
if( ns_name_ntop( srv[cnt] + SRV_SERVER, (char*)srvname, NS_MAXDNAME ) < 0 )
printf( "handle this error!\n" );
servers[(char*)srvname] = ns_get16( srv[cnt] + SRV_PORT );
}
return servers;
}
int
dns_get_mx_list(const char *host, int port, struct mx_hostentry **he, int no_mx)
{
char outname[MAXDNAME];
ns_msg msg;
ns_rr rr;
const char *searchhost;
const unsigned char *cp;
unsigned char *ans;
struct mx_hostentry *hosts = NULL;
size_t nhosts = 0;
size_t anssz;
int pref;
int cname_recurse;
int err;
int i;
res_init();
searchhost = host;
cname_recurse = 0;
anssz = 65536;
ans = malloc(anssz);
if (ans == NULL)
return (1);
if (no_mx)
goto out;
repeat:
err = res_search(searchhost, ns_c_in, ns_t_mx, ans, anssz);
if (err < 0) {
switch (h_errno) {
case NO_DATA:
/*
* Host exists, but no MX (or CNAME) entry.
* Not an error, use host name instead.
*/
goto out;
case TRY_AGAIN:
/* transient error */
goto transerr;
case NO_RECOVERY:
case HOST_NOT_FOUND:
default:
errno = ENOENT;
goto err;
}
}
if (!ns_initparse(ans, anssz, &msg))
goto transerr;
switch (ns_msg_getflag(msg, ns_f_rcode)) {
case ns_r_noerror:
break;
case ns_r_nxdomain:
goto err;
default:
goto transerr;
}
for (i = 0; i < ns_msg_count(msg, ns_s_an); i++) {
if (ns_parserr(&msg, ns_s_an, i, &rr))
goto transerr;
cp = ns_rr_rdata(rr);
switch (ns_rr_type(rr)) {
case ns_t_mx:
pref = ns_get16(cp);
cp += 2;
err = ns_name_uncompress(ns_msg_base(msg), ns_msg_end(msg),
cp, outname, sizeof(outname));
if (err < 0)
goto transerr;
add_host(pref, outname, port, &hosts, &nhosts);
break;
case ns_t_cname:
err = ns_name_uncompress(ns_msg_base(msg), ns_msg_end(msg),
cp, outname, sizeof(outname));
if (err < 0)
goto transerr;
/* Prevent a CNAME loop */
if (cname_recurse++ > 10)
goto err;
searchhost = outname;
goto repeat;
default:
break;
}
}
out:
err = 0;
if (0) {
transerr:
if (nhosts == 0)
err = 1;
}
if (0) {
err:
err = -1;
}
free(ans);
if (!err) {
/*
* If we didn't find any MX, use the hostname instead.
*/
if (nhosts == 0)
add_host(0, searchhost, port, &hosts, &nhosts);
qsort(hosts, nhosts, sizeof(*hosts), sort_pref);
}
if (nhosts > 0) {
/* terminate list */
*hosts[nhosts].host = 0;
} else {
if (hosts != NULL)
free(hosts);
hosts = NULL;
}
*he = hosts;
return (err);
free(ans);
if (hosts != NULL)
free(hosts);
return (err);
}
/**
* create_naptr_record()
*/
static NAPTR_record *create_naptr_record(const ns_msg *handle,
const ns_rr *rr) {
size_t rdchars;
const u_char *rdata, *edata;
const u_char *message = ns_msg_base(*handle);
size_t message_len = ns_msg_size(*handle);
char buf[NS_MAXDNAME]; /* defined in nameser.h */
NAPTR_record *naptr_record = malloc(sizeof(NAPTR_record));
memset(naptr_record,0,sizeof(NAPTR_record));
/*
** Domain field
*/
naptr_record->domain = strdup(ns_rr_name(*rr));
/*
** TTL field
*/
naptr_record->ttl = ns_rr_ttl(*rr);
/*
** Copy from rdata
** (borrowed from BIND-8.2.2 ns_print.c)
*/
rdata = ns_rr_rdata(*rr);
edata = rdata+ns_rr_rdlen(*rr);
/*
** Order & preference field
*/
naptr_record->order = ns_get16(rdata);
rdata += NS_INT16SZ;
naptr_record->preference = ns_get16(rdata);
rdata += NS_INT16SZ;
/*
** Flags field
*/
if((naptr_record->flags = get_rdata_str(rdata,edata,&rdchars))==NULL) {
free_naptr_record(naptr_record);
return NULL;
}
rdata += rdchars;
/*
** Service field
*/
if((naptr_record->service = get_rdata_str(rdata,edata,&rdchars))==NULL) {
free_naptr_record(naptr_record);
return NULL;
}
rdata += rdchars;
/*
** RegExp field
*/
if((naptr_record->regexp = get_rdata_str(rdata,edata,&rdchars))==NULL) {
free_naptr_record(naptr_record);
return NULL;
}
rdata += rdchars;
/*
** Replacement field
** Note: dn_expand() sets the first character to '\0' for the root,
** we are going to set it back to '.'
*/
if(dn_expand(message,message+message_len,rdata,buf,NS_MAXDNAME)==-1) {
free_naptr_record(naptr_record);
return NULL;
}
if(buf[0]=='\0') {
buf[0]='.';
buf[1]='\0';
}
naptr_record->replacement = strdup(buf);
return naptr_record;
}
/* Setup a client socket for the named service over the given protocol under
* the given domain name.
*/
static int insrv_lookup (int (*mksox) (int,const struct sockaddr *,socklen_t),
char *service, char *proto, char *domain,
char *cnxhost, size_t cnxhlen, int *cnxport) {
// 1. convert service/proto to svcnm
// 2. construct SRV query for _service._proto.domain
// 3. try connecting to all answers in turn
// 4. if no SRV records exist, lookup A record to connect to on stdport
// 5. return connection socket or error code
iobuf query, names;
name svcnm;
int error=0;
int ctr;
int rnd;
int sox=0;
HEADER *nameshdr;
unsigned char *here, *srv[MAXNUM_SRV], *ip;
int num_srv=0;
// Storage for fallback SRV list, constructed when DNS gives no SRV
unsigned char fallbacksrv [2*(MAXCDNAME+SRV_FIXEDSZ+MAXCDNAME)];
srv_flags &= ~SRV_GOT_MASK;
srv_flags |= SRV_GOT_SRV;
strcpy (svcnm, "_");
strcat (svcnm, service);
strcat (svcnm, "._");
strcat (svcnm, proto);
// Note that SRV records are only defined for class IN
if (domain) {
names.len=res_querydomain (svcnm, domain,
C_IN, T_SRV,
names.buf, PACKETSZ);
} else {
names.len=res_query (svcnm,
C_IN, T_SRV,
names.buf, PACKETSZ);
}
if (names.len < 0) {
error = -ENOENT;
goto fallback;
}
nameshdr=(HEADER *) names.buf;
here=names.buf + HFIXEDSZ;
rnd=nameshdr->id; // Heck, gimme one reason why not!
if ((names.len < HFIXEDSZ) || nameshdr->tc) {
error = -EMSGSIZE;
}
switch (nameshdr->rcode) {
case 1:
error = -EFAULT;
goto fallback;
case 2:
error = -EAGAIN;
goto fallback;
case 3:
error = -ENOENT;
goto fallback;
case 4:
error = -ENOSYS;
goto fallback;
case 5:
error = -EPERM;
goto fallback;
default:
break;
}
if (ntohs (nameshdr->ancount) == 0) {
error = -ENOENT;
goto fallback;
}
if (ntohs (nameshdr->ancount) > MAXNUM_SRV) {
error = -ERANGE;
goto fallback;
}
for (ctr=ntohs (nameshdr->qdcount); ctr>0; ctr--) {
int strlen=dn_skipname (here, names.buf+names.len);
here += strlen + QFIXEDSZ;
}
for (ctr=ntohs (nameshdr->ancount); ctr>0; ctr--) {
int strlen=dn_skipname (here, names.buf+names.len);
here += strlen;
srv [num_srv++] = here;
here += SRV_FIXEDSZ;
here += dn_skipname (here, names.buf+names.len);
}
// In case an error occurred, there are no SRV records.
// Fallback strategy now is: construct two. One with the domain name,
// the other with the /standard/ service name prefixed.
// Note: Assuming a domain without the service name prefixed!
fallback:
if (error) {
struct servent *servent = getservbyname (service, proto);
srv_flags &= ~SRV_GOT_MASK;
srv_flags |= SRV_GOT_A;
num_srv = 2;
if (!servent) {
return error; // First error returned
}
srv [0] = here = fallbacksrv;
// Only few record fields are really needed:
*(unsigned short *)(here + SRV_COST) = htons (0);
*(unsigned short *)(here + SRV_WEIGHT) = htons (0);
*(unsigned short *)(here + SRV_PORT) = servent->s_port;
here += SRV_FIXEDSZ;
if (domain) {
here += dn_comp (domain, here, MAXCDNAME, NULL, NULL);
}
// Forget about the name whose SRV IN this is, no need for it
srv [1] = here;
// Only few record fields are really needed:
*(unsigned short *)(here + SRV_COST) = htons (1);
*(unsigned short *)(here + SRV_WEIGHT) = htons (0);
*(unsigned short *)(here + SRV_PORT) = servent->s_port;
here += SRV_FIXEDSZ;
here += dn_comp (servent->s_name, here, MAXCDNAME, NULL, NULL);
here--; // Go back to overwrite final zero byte
if (domain) {
here += dn_comp (domain, here, MAXCDNAME, NULL, NULL);
}
rnd = 1;
}
// End of fallback construction, making sure that variables are defined
// srv[] points to the SRV RR, num_srv counts the number of entries.
// Every SRV RR has at least cost, weight, port and servername set.
#ifdef DEBUG
for (ctr=0; ctr<num_srv; ctr++) {
name srvname;
if (ns_name_ntop (srv [ctr]+SRV_SERVER, srvname, MAXDNAME) < 0) {
return -errno;
}
printf ("Considering SRV server %d %d %d\t%s\n",
ns_get16 (srv [ctr]+SRV_COST),
ns_get16 (srv [ctr]+SRV_WEIGHT),
ns_get16 (srv [ctr]+SRV_PORT),
srvname
);
}
#endif
// Overwrite weight with rnd-spread version to divide load over weights
for (ctr=0; ctr<num_srv; ctr++) {
*(unsigned short *)(srv [ctr]+SRV_WEIGHT)
= rnd % (1+ns_get16 (srv [ctr]+SRV_WEIGHT));
}
qsort (srv, num_srv, sizeof (*srv), srvcmp);
for (ctr=0; ctr<num_srv; ctr++) {
name srvname;
struct hostent *host;
// Open a socket to connect with
int sox = socket (PF_INET, (*proto!='u')? SOCK_STREAM: SOCK_DGRAM, 0);
if (sox < 0) {
return -errno;
}
if (ns_name_ntop (srv [ctr]+SRV_SERVER, srvname, MAXDNAME) < 0) {
return -errno;
}
#ifdef DEBUG
printf ("Trying SRV server %d %d\t%s\n",
ns_get16 (srv [ctr]+SRV_COST),
*(unsigned short *)(srv [ctr]+SRV_WEIGHT),
srvname
);
#endif
if ((host=gethostbyname (srvname))
&& (host->h_addrtype == AF_INET)) {
char **ip=host->h_addr_list;
while (*ip) {
char *ipnr=*ip;
struct sockaddr_in sin;
memset (&sin, 0, sizeof (sin));
sin.sin_family = AF_INET;
memcpy (&sin.sin_addr,
ipnr,
sizeof (sin.sin_addr));
sin.sin_port = *(unsigned short *) (srv [ctr]+SRV_PORT);
#ifdef DEBUG
fprintf (stderr, "\tbind_connect (%d, 0x%08lx, %d)\t",
sox,
ntohl(*(unsigned long *)ipnr),
ntohs (sin.sin_port));
#endif
#ifdef DEBUG
if (mksox == connect) {
printf ("mksox == connect\n");
}
if (mksox == bind) {
printf ("mksox == bind\n");
}
{ int i; printf ("SIN ="); for (i=0; i<sizeof (sin); i++) printf (" %02x", (int) (((unsigned char *) &sin) [i])); printf ("\n"); }
#endif
if (mksox (sox, (struct sockaddr *) &sin, sizeof (sin)) == 0) {
#ifdef DEBUG
fprintf (stderr, "Connected or bound to %s:%d\n", srvname, ntohs (sin.sin_port));
#endif
if (cnxhost) {
if (strlen (cnxhost) > cnxhlen-1) {
*cnxhost = '\0';
} else {
strncpy (cnxhost,srvname,cnxhlen);
}
}
if (cnxport) {
*cnxport = ntohs (sin.sin_port);
}
return sox;
} else {
if (!error) {
error = -errno;
}
}
ip++;
}
}
#ifdef DEBUG
printf ("Closing socket %d\n", sox);
#endif
close (sox);
}
if (!error) {
error = -ENOENT;
}
return error;
}
void PlatformDomainNameServiceQuery::runBlocking() {
if (!serviceValid) {
emitError();
return;
}
SWIFT_LOG(debug) << "Querying " << service << std::endl;
std::vector<DomainNameServiceQuery::Result> records;
#if defined(SWIFTEN_PLATFORM_WINDOWS)
DNS_RECORD* responses;
// FIXME: This conversion doesn't work if unicode is deffed above
if (DnsQuery(service.c_str(), DNS_TYPE_SRV, DNS_QUERY_STANDARD, NULL, &responses, NULL) != ERROR_SUCCESS) {
emitError();
return;
}
DNS_RECORD* currentEntry = responses;
while (currentEntry) {
if (currentEntry->wType == DNS_TYPE_SRV) {
DomainNameServiceQuery::Result record;
record.priority = currentEntry->Data.SRV.wPriority;
record.weight = currentEntry->Data.SRV.wWeight;
record.port = currentEntry->Data.SRV.wPort;
// The pNameTarget is actually a PCWSTR, so I would have expected this
// conversion to not work at all, but it does.
// Actually, it doesn't. Fix this and remove explicit cast
// Remove unicode undef above as well
record.hostname = std::string((const char*) currentEntry->Data.SRV.pNameTarget);
records.push_back(record);
}
currentEntry = currentEntry->pNext;
}
DnsRecordListFree(responses, DnsFreeRecordList);
#else
// Make sure we reinitialize the domain list every time
res_init();
ByteArray response;
response.resize(NS_PACKETSZ);
int responseLength = res_query(const_cast<char*>(service.c_str()), ns_c_in, ns_t_srv, reinterpret_cast<u_char*>(vecptr(response)), response.size());
if (responseLength == -1) {
SWIFT_LOG(debug) << "Error" << std::endl;
emitError();
return;
}
// Parse header
HEADER* header = reinterpret_cast<HEADER*>(vecptr(response));
unsigned char* messageStart = vecptr(response);
unsigned char* messageEnd = messageStart + responseLength;
unsigned char* currentEntry = messageStart + NS_HFIXEDSZ;
// Skip over the queries
int queriesCount = ntohs(header->qdcount);
while (queriesCount > 0) {
int entryLength = dn_skipname(currentEntry, messageEnd);
if (entryLength < 0) {
emitError();
return;
}
currentEntry += entryLength + NS_QFIXEDSZ;
queriesCount--;
}
// Process the SRV answers
int answersCount = ntohs(header->ancount);
while (answersCount > 0) {
DomainNameServiceQuery::Result record;
int entryLength = dn_skipname(currentEntry, messageEnd);
currentEntry += entryLength;
currentEntry += NS_RRFIXEDSZ;
// Priority
if (currentEntry + 2 >= messageEnd) {
emitError();
return;
}
record.priority = boost::numeric_cast<int>(ns_get16(currentEntry));
currentEntry += 2;
// Weight
if (currentEntry + 2 >= messageEnd) {
emitError();
return;
}
record.weight = boost::numeric_cast<int>(ns_get16(currentEntry));
currentEntry += 2;
// Port
if (currentEntry + 2 >= messageEnd) {
emitError();
return;
}
record.port = boost::numeric_cast<int>(ns_get16(currentEntry));
currentEntry += 2;
// Hostname
if (currentEntry >= messageEnd) {
emitError();
return;
}
ByteArray entry;
entry.resize(NS_MAXDNAME);
entryLength = dn_expand(messageStart, messageEnd, currentEntry, reinterpret_cast<char*>(vecptr(entry)), entry.size());
if (entryLength < 0) {
emitError();
return;
}
record.hostname = std::string(reinterpret_cast<const char*>(vecptr(entry)));
records.push_back(record);
currentEntry += entryLength;
answersCount--;
}
#endif
BoostRandomGenerator generator;
DomainNameServiceQuery::sortResults(records, generator);
//std::cout << "Sending out " << records.size() << " SRV results " << std::endl;
eventLoop->postEvent(boost::bind(boost::ref(onResult), records), shared_from_this());
}
int
SendRequest(union res_sockaddr_union *nsAddrPtr, const u_char *buf,
int buflen, u_char *answer, u_int anslen, int *trueLenPtr)
{
int n, try, v_circuit, resplen;
ISC_SOCKLEN_T salen;
int gotsomewhere = 0, connected = 0;
int connreset = 0;
u_short id, len;
u_char *cp;
fd_set dsmask;
struct timeval timeout;
const HEADER *hp = (const HEADER *) buf;
HEADER *anhp = (HEADER *) answer;
struct iovec iov[2];
int terrno = ETIMEDOUT;
char junk[512];
struct sockaddr_storage sa;
int family = nsAddrPtr->sin.sin_family;
int clen = (family == AF_INET) ? sizeof(struct sockaddr_in) :
sizeof(struct sockaddr_in6);
if (res.options & RES_DEBUG2) {
printf("------------\nSendRequest(), len %d\n", buflen);
Print_query(buf, buf + buflen, 1);
}
v_circuit = (res.options & RES_USEVC) || buflen > PACKETSZ;
id = hp->id;
/*
* Send request, RETRY times, or until successful
*/
for (try = 0; try < res.retry; try++) {
usevc:
if (v_circuit) {
int truncated = 0;
/*
* Use virtual circuit;
* at most one attempt per server.
*/
try = res.retry;
if (s < 0) {
s = socket(family, SOCK_STREAM, 0);
if (s < 0) {
terrno = errno;
if (res.options & RES_DEBUG)
perror("socket (vc) failed");
continue;
}
if (connect(s, (struct sockaddr *)nsAddrPtr,
clen) < 0) {
terrno = errno;
if (res.options & RES_DEBUG)
perror("connect failed");
(void) close(s);
s = -1;
continue;
}
}
/*
* Send length & message
*/
__putshort(buflen, (u_char *)&len);
iov[0].iov_base = (caddr_t)&len;
iov[0].iov_len = INT16SZ;
DE_CONST(buf, iov[1].iov_base);
iov[1].iov_len = buflen;
if (writev(s, iov, 2) != INT16SZ + buflen) {
terrno = errno;
if (res.options & RES_DEBUG)
perror("write failed");
(void) close(s);
s = -1;
continue;
}
/*
* Receive length & response
*/
cp = answer;
len = INT16SZ;
while ((n = read(s, (char *)cp, (int)len)) > 0) {
cp += n;
if ((len -= n) <= 0)
break;
}
if (n <= 0) {
terrno = errno;
if (res.options & RES_DEBUG)
perror("read failed");
(void) close(s);
s = -1;
/*
* A long running process might get its TCP
* connection reset if the remote server was
* restarted. Requery the server instead of
* trying a new one. When there is only one
* server, this means that a query might work
* instead of failing. We only allow one reset
* per query to prevent looping.
*/
if (terrno == ECONNRESET && !connreset) {
connreset = 1;
}
continue;
}
cp = answer;
if ((resplen = ns_get16((u_char*)cp)) > (int)anslen) {
if (res.options & RES_DEBUG)
fprintf(stderr, "response truncated\n");
len = anslen;
truncated = 1;
} else
len = resplen;
while (len != 0 &&
(n = read(s, (char *)cp, (int)len)) > 0) {
cp += n;
len -= n;
}
if (n <= 0) {
terrno = errno;
if (res.options & RES_DEBUG)
perror("read failed");
(void) close(s);
s = -1;
continue;
}
if (truncated) {
/*
* Flush rest of answer
* so connection stays in synch.
*/
anhp->tc = 1;
len = resplen - anslen;
while (len != 0) {
n = (len > sizeof(junk) ?
sizeof(junk) : len);
if ((n = read(s, junk, n)) > 0)
len -= n;
else
break;
}
}
} else {
/*
* Use datagrams.
*/
if (s < 0) {
s = socket(family, SOCK_DGRAM, 0);
if (s < 0) {
terrno = errno;
if (res.options & RES_DEBUG)
perror("socket (dg) failed");
continue;
}
}
#if BSD >= 43
if (connected == 0) {
if (connect(s, (struct sockaddr *)nsAddrPtr,
clen) < 0) {
if (res.options & RES_DEBUG)
perror("connect");
continue;
}
connected = 1;
}
if (send(s, buf, buflen, 0) != buflen) {
if (res.options & RES_DEBUG)
perror("send");
continue;
}
#else /* BSD */
if (sendto(s, (const char *)buf, buflen, 0,
(struct sockaddr *) nsAddrPtr,
clen) != buflen) {
if (res.options & RES_DEBUG)
perror("sendto");
continue;
}
#endif
/*
* Wait for reply
*/
timeout.tv_sec = (res.retrans << try);
if (timeout.tv_sec <= 0)
timeout.tv_sec = 1;
timeout.tv_usec = 0;
wait:
FD_ZERO(&dsmask);
FD_SET(s, &dsmask);
n = select(s+1, &dsmask, (fd_set *)NULL,
(fd_set *)NULL, &timeout);
if (n < 0) {
if (res.options & RES_DEBUG)
perror("select");
continue;
}
if (n == 0) {
/*
* timeout
*/
if (res.options & RES_DEBUG)
printf("timeout\n");
#if BSD >= 43
gotsomewhere = 1;
#endif
continue;
}
salen = sizeof sa;
resplen = recvfrom(s, (char *)answer, anslen, 0,
(struct sockaddr *)&sa, &salen);
if (resplen <= 0) {
if (res.options & RES_DEBUG)
perror("recvfrom");
continue;
}
gotsomewhere = 1;
if (id != anhp->id) {
/*
* response from old query, ignore it
*/
if (res.options & RES_DEBUG2) {
printf("------------\nOld answer:\n");
Print_query(answer, answer+resplen, 1);
}
goto wait;
}
if (!(res.options & RES_IGNTC) && anhp->tc) {
/*
* get rest of answer;
* use TCP with same server.
*/
if (res.options & RES_DEBUG)
printf("truncated answer\n");
(void) close(s);
s = -1;
v_circuit = 1;
goto usevc;
}
}
if (res.options & RES_DEBUG) {
if (res.options & RES_DEBUG2)
printf("------------\nGot answer (%d bytes):\n",
resplen);
else
printf("------------\nGot answer:\n");
Print_query(answer, answer+resplen, 1);
}
(void) close(s);
s = -1;
*trueLenPtr = resplen;
return (SUCCESS);
}
if (s >= 0) {
(void) close(s);
s = -1;
}
if (v_circuit == 0)
if (gotsomewhere == 0)
return NO_RESPONSE; /* no nameservers found */
else
return TIME_OUT; /* no answer obtained */
else
if (errno == ECONNREFUSED)
return NO_RESPONSE;
else
return ERROR;
}
/*
* Fill out host list, based on DNS lookups.
* This is not reentrant. Better be called before any other threads
* are started.
*/
int cldc_getaddr(GList **host_list, const char *thishost, struct hail_log *log)
{
enum { hostsz = 64 };
char cldb[hostsz];
unsigned char resp[512];
int rlen;
ns_msg nsb;
ns_rr rrb;
int rrlen;
char hostb[hostsz];
int i;
struct cldc_host hp;
const unsigned char *p;
int rc;
int search_retries = 10;
/*
* We must create FQDN or else the first thing the resolver does
* is a lookup in the DNS root (probably the standard-compliant
* dot between "_cld" and "_udp" hurts us here).
*/
if (cldc_make_fqdn(cldb, hostsz, "_cld._udp", thishost) != 0) {
HAIL_INFO(log, "internal error in cldc_make_fqdn(%s)",
thishost);
return -1;
}
do_try_again:
rc = res_search(cldb, ns_c_in, ns_t_srv, resp, 512);
if (rc < 0) {
switch (h_errno) {
case HOST_NOT_FOUND:
HAIL_INFO(log, "%s: No _cld._udp SRV record", __func__);
return -1;
case NO_DATA:
HAIL_INFO(log, "%s: Cannot find _cld._udp"
" SRV record", __func__);
return -1;
case TRY_AGAIN:
if (search_retries-- > 0)
goto do_try_again;
/* fall through */
case NO_RECOVERY:
default:
HAIL_ERR(log, "%s: res_search error (%d): %s",
__func__, h_errno, hstrerror(h_errno));
return -1;
}
}
rlen = rc;
if (rlen == 0) {
HAIL_INFO(log, "%s: res_search returned empty reply", __func__);
return -1;
}
if (ns_initparse(resp, rlen, &nsb) < 0) {
HAIL_ERR(log, "%s: ns_initparse error", __func__);
return -1;
}
for (i = 0; i < ns_msg_count(nsb, ns_s_an); i++) {
rc = ns_parserr(&nsb, ns_s_an, i, &rrb);
if (rc < 0)
continue;
if (ns_rr_class(rrb) != ns_c_in)
continue;
memset(&hp, 0, sizeof(hp));
switch (ns_rr_type(rrb)) {
case ns_t_srv:
rrlen = ns_rr_rdlen(rrb);
if (rrlen < 8) { /* 2+2+2 and 2 for host */
HAIL_DEBUG(log, "%s: SRV len %d",
__func__, rrlen);
break;
}
p = ns_rr_rdata(rrb);
rc = dn_expand(resp, resp+rlen, p+6, hostb, hostsz);
if (rc < 0) {
HAIL_DEBUG(log, "%s: dn_expand error %d",
__func__, rc);
break;
}
if (rc < 2) {
HAIL_DEBUG(log, "%s: dn_expand short %d",
__func__, rc);
break;
}
if (cldc_saveaddr(&hp, ns_get16(p+0),
ns_get16(p+2), ns_get16(p+4),
rc, hostb, NULL))
break;
HAIL_DEBUG(log, "%s: found CLD host %s port %u"
" prio %d weight %d",
__func__, hp.host, hp.port,
hp.prio, hp.weight);
push_host(host_list, &hp);
break;
case ns_t_cname: /* impossible, but */
HAIL_DEBUG(log, "%s: CNAME in SRV request, ignored",
__func__);
break;
default:
;
}
}
return 0;
}
/* Setup a client socket for the named service over the given protocol under
* the given domain name.
*/
int insrv_lookup (const char *service, const char *proto, const char *domain,
list<t_dns_result> &result)
{
// 1. convert service/proto to svcnm
// 2. construct SRV query for _service._proto.domain
iobuf names;
name svcnm;
int ctr;
int rnd;
HEADER *nameshdr;
unsigned char *here, *srv[MAXNUM_SRV];
int num_srv=0;
// Storage for fallback SRV list, constructed when DNS gives no SRV
//unsigned char fallbacksrv [2*(MAXCDNAME+SRV_FIXEDSZ+MAXCDNAME)];
// srv_flags &= ~SRV_GOT_MASK;
// srv_flags |= SRV_GOT_SRV;
strcpy (svcnm, "_");
strcat (svcnm, service);
strcat (svcnm, "._");
strcat (svcnm, proto);
// Note that SRV records are only defined for class IN
if (domain) {
names.len=res_querydomain (svcnm, domain,
C_IN, T_SRV,
names.buf, PACKETSZ);
} else {
names.len=res_query (svcnm,
C_IN, T_SRV,
names.buf, PACKETSZ);
}
if (names.len < 0) {
return -ENOENT;
}
nameshdr=(HEADER *) names.buf;
here=names.buf + HFIXEDSZ;
rnd=nameshdr->id; // Heck, gimme one reason why not!
if ((names.len < HFIXEDSZ) || nameshdr->tc) {
return -EMSGSIZE;
}
switch (nameshdr->rcode) {
case 1:
return -EFAULT;
case 2:
return -EAGAIN;
case 3:
return -ENOENT;
case 4:
return -ENOSYS;
case 5:
return -EPERM;
default:
break;
}
if (ntohs (nameshdr->ancount) == 0) {
return -ENOENT;
}
if (ntohs (nameshdr->ancount) > MAXNUM_SRV) {
return -ERANGE;
}
for (ctr=ntohs (nameshdr->qdcount); ctr>0; ctr--) {
int strlen=dn_skipname (here, names.buf+names.len);
here += strlen + QFIXEDSZ;
}
for (ctr=ntohs (nameshdr->ancount); ctr>0; ctr--) {
int strlen=dn_skipname (here, names.buf+names.len);
here += strlen;
srv [num_srv++] = here;
here += SRV_FIXEDSZ;
here += dn_skipname (here, names.buf+names.len);
}
// Overwrite weight with rnd-spread version to divide load over weights
for (ctr=0; ctr<num_srv; ctr++) {
*(unsigned short *) (srv [ctr]+SRV_WEIGHT)
= htons(rnd % (1+ns_get16 (srv [ctr]+SRV_WEIGHT)));
}
qsort (srv, num_srv, sizeof (*srv), srvcmp);
result.clear();
for (ctr=0; ctr<num_srv; ctr++) {
name srvname;
if (ns_name_ntop (srv [ctr]+SRV_SERVER, srvname, MAXDNAME) < 0) {
return -errno;
}
t_dns_result r;
r.hostname = srvname;
r.port = ns_get16(srv [ctr]+SRV_PORT);
result.push_back(r);
}
return 0;
}