static const unsigned char *display_question(const unsigned char *aptr,
const unsigned char *abuf, int alen,
dns_resp_t *response)
{
char *name;
int type, dnsclass, status;
long len;
/* Parse the question name. */
status = ares_expand_name(aptr, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
aptr += len;
/* Make sure there's enough data after the name for the fixed part
* of the question.
*/
if (aptr + QFIXEDSZ > abuf + alen) {
xfree(name);
return NULL;
}
/* Parse the question type and class. */
type = DNS_QUESTION_TYPE(aptr);
dnsclass = DNS_QUESTION_CLASS(aptr);
aptr += QFIXEDSZ;
/*
* Display the question, in a format sort of similar to how we will
* display RRs.
*/
sprintf(msg, "\t%-15s.\t", name);
addtobuffer(response->msgbuf, msg);
if (dnsclass != C_IN) {
sprintf(msg, "\t%s", class_name(dnsclass));
addtobuffer(response->msgbuf, msg);
}
sprintf(msg, "\t%s\n", type_name(type));
addtobuffer(response->msgbuf, msg);
xfree(name);
return aptr;
}
void LLQueryResponder::queryResult(const char *buf, size_t len)
{
const char *pos = buf;
int qdcount = DNS_HEADER_QDCOUNT(pos);
int ancount = DNS_HEADER_ANCOUNT(pos);
int nscount = DNS_HEADER_NSCOUNT(pos);
int arcount = DNS_HEADER_ARCOUNT(pos);
int ret;
if (qdcount == 0 || ancount + nscount + arcount == 0)
{
ret = ARES_ENODATA;
goto bail;
}
pos += NS_HFIXEDSZ;
for (int i = 0; i < qdcount; i++)
{
std::string ignore;
size_t enclen;
ret = LLAres::expandName(pos, buf, len, i == 0 ? mQuery : ignore,
enclen);
if (ret != ARES_SUCCESS)
{
goto bail;
}
pos += enclen;
if (i == 0)
{
int t = DNS_QUESTION_TYPE(pos);
switch (t)
{
case RES_A:
case RES_NS:
case RES_CNAME:
case RES_PTR:
case RES_AAAA:
case RES_SRV:
mType = (LLResType) t;
break;
default:
LL_INFOS() << "Cannot grok query type " << t << LL_ENDL;
ret = ARES_EBADQUERY;
goto bail;
}
}
pos += NS_QFIXEDSZ;
if (pos > buf + len)
{
ret = ARES_EBADRESP;
goto bail;
}
}
ret = parseSection(buf, len, ancount, pos, mAnswers);
if (ret != ARES_SUCCESS)
{
goto bail;
}
ret = parseSection(buf, len, nscount, pos, mAuthorities);
if (ret != ARES_SUCCESS)
{
goto bail;
}
ret = parseSection(buf, len, arcount, pos, mAdditional);
bail:
mResult = ret;
if (mResult == ARES_SUCCESS)
{
querySuccess();
} else {
queryError(mResult);
}
}
/* parse reply record */
int evdns_parse_reply(unsigned char *buf, int nbuf, HOSTENT *hostent)
{
unsigned char *p = NULL, *end = NULL, *s = NULL, *ps = NULL;
int i = 0, qdcount = 0, ancount = 0, nscount = 0, arcount = 0,
qr = 0, opcode = 0, aa = 0, tc = 0, rd = 0,
ra = 0, rcode = 0, type = 0, dnsclass = 0, ttl = 0, rrlen = 0;
if(buf && nbuf > HFIXEDSZ)
{
hostent->naddrs = 0;
hostent->nalias = 0;
p = buf;
end = buf + nbuf;
hostent->qid = DNS_HEADER_QID(p);
qr = DNS_HEADER_QR(p);
opcode = DNS_HEADER_OPCODE(p);
aa = DNS_HEADER_AA(p);
tc = DNS_HEADER_TC(p);
rd = DNS_HEADER_RD(p);
ra = DNS_HEADER_RA(p);
rcode = DNS_HEADER_RCODE(p);
qdcount = DNS_HEADER_QDCOUNT(p);
ancount = DNS_HEADER_ANCOUNT(p);
nscount = DNS_HEADER_NSCOUNT(p);
arcount = DNS_HEADER_ARCOUNT(p);
p += HFIXEDSZ;
/* Display the answer header. */
/*
printf("id: %d\n", id);
printf("flags: %s%s%s%s%s\n",
qr ? "qr " : "",
aa ? "aa " : "",
tc ? "tc " : "",
rd ? "rd " : "",
ra ? "ra " : "");
printf("opcode: %s\n", opcodes[opcode]);
printf("rcode: %s\n", rcodes[rcode]);
fprintf(stdout, "qdcount:%d\nancount:%d\nnscount:%d\narcount:%d\n",
qdcount, ancount, nscount, arcount);
*/
/* parse question */
for(i = 0; i < qdcount; i++)
{
ps = (unsigned char *)hostent->name;
p = evdns_expand_name(p, buf, end, ps);
/* Parse the question type and class. */
type = DNS_QUESTION_TYPE(p);
dnsclass = DNS_QUESTION_CLASS(p);
p += QFIXEDSZ;
/*
fprintf(stdout, "qname:%-15s", name);
fprintf(stdout, "\tqtype:%d", type);
fprintf(stdout, "\tqclass:%d\r\n", dnsclass);
*/
}
/* parse A name */
for(i = 0; i < ancount; i++)
{
ps = (unsigned char *)hostent->alias[hostent->nalias++];
p = evdns_expand_name(p, buf, end, ps);
type = DNS_RR_TYPE(p);
dnsclass = DNS_RR_CLASS(p);
ttl = DNS_RR_TTL(p);
rrlen = DNS_RR_LEN(p);
p += RRFIXEDSZ;
/*
fprintf(stdout, "name:%s type:%d dnsclass:%d ttl:%d rrlen:%d ",
name, type, dnsclass, ttl, rrlen);
*/
/* addr name */
if(type == TYPE_ANAME)
{
hostent->addrs[hostent->naddrs++] = *((int *)p);
}
/* Canonical name */
else if(type == TYPE_CNAME)
{
ps = (unsigned char *)hostent->alias[hostent->nalias++];
s = evdns_expand_name(p, buf, end, ps);
//fprintf(stdout, "cname:%s ", cname);
}
/* pointer */
else if(type == TYPE_PTR)
{
ps = (unsigned char *)hostent->alias[hostent->nalias++];
s = evdns_expand_name(p, buf, end, ps);
//fprintf(stdout, "pointer:%s ", cname);
}
//fprintf(stdout, "\r\n");
p += rrlen;
}
return 0;
}
return -1;
}
static int same_questions(const unsigned char *qbuf, int qlen,
const unsigned char *abuf, int alen)
{
struct {
const unsigned char *p;
int qdcount;
char *name;
long int namelen;
int type;
int dnsclass;
} q, a;
int i, j;
if (qlen < HFIXEDSZ || alen < HFIXEDSZ)
return 0;
/* Extract qdcount from the request and reply buffers and compare them. */
q.qdcount = DNS_HEADER_QDCOUNT(qbuf);
a.qdcount = DNS_HEADER_QDCOUNT(abuf);
if (q.qdcount != a.qdcount)
return 0;
/* For each question in qbuf, find it in abuf. */
q.p = qbuf + HFIXEDSZ;
for (i = 0; i < q.qdcount; i++)
{
/* Decode the question in the query. */
if (ares_expand_name(q.p, qbuf, qlen, &q.name, &q.namelen)
!= ARES_SUCCESS)
return 0;
q.p += q.namelen;
if (q.p + QFIXEDSZ > qbuf + qlen)
{
free(q.name);
return 0;
}
q.type = DNS_QUESTION_TYPE(q.p);
q.dnsclass = DNS_QUESTION_CLASS(q.p);
q.p += QFIXEDSZ;
/* Search for this question in the answer. */
a.p = abuf + HFIXEDSZ;
for (j = 0; j < a.qdcount; j++)
{
/* Decode the question in the answer. */
if (ares_expand_name(a.p, abuf, alen, &a.name, &a.namelen)
!= ARES_SUCCESS)
{
free(q.name);
return 0;
}
a.p += a.namelen;
if (a.p + QFIXEDSZ > abuf + alen)
{
free(q.name);
free(a.name);
return 0;
}
a.type = DNS_QUESTION_TYPE(a.p);
a.dnsclass = DNS_QUESTION_CLASS(a.p);
a.p += QFIXEDSZ;
/* Compare the decoded questions. */
if (strcasecmp(q.name, a.name) == 0 && q.type == a.type
&& q.dnsclass == a.dnsclass)
{
free(a.name);
break;
}
free(a.name);
}
free(q.name);
if (j == a.qdcount)
return 0;
}
return 1;
}
