static const unsigned char *display_rr(const unsigned char *aptr,
const unsigned char *abuf, int alen)
{
const unsigned char *p;
int type, dnsclass, ttl, dlen, status;
long len;
char addr[46];
union {
unsigned char * as_uchar;
char * as_char;
} name;
/* Parse the RR name. */
status = ares_expand_name(aptr, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
aptr += len;
/* Make sure there is enough data after the RR name for the fixed
* part of the RR.
*/
if (aptr + RRFIXEDSZ > abuf + alen)
{
ares_free_string(name.as_char);
return NULL;
}
/* Parse the fixed part of the RR, and advance to the RR data
* field. */
type = DNS_RR_TYPE(aptr);
dnsclass = DNS_RR_CLASS(aptr);
ttl = DNS_RR_TTL(aptr);
dlen = DNS_RR_LEN(aptr);
aptr += RRFIXEDSZ;
if (aptr + dlen > abuf + alen)
{
ares_free_string(name.as_char);
return NULL;
}
/* Display the RR name, class, and type. */
printf("\t%-15s.\t%d", name.as_char, ttl);
if (dnsclass != C_IN)
printf("\t%s", class_name(dnsclass));
printf("\t%s", type_name(type));
ares_free_string(name.as_char);
/* Display the RR data. Don't touch aptr. */
switch (type)
{
case T_CNAME:
case T_MB:
case T_MD:
case T_MF:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
/* For these types, the RR data is just a domain name. */
status = ares_expand_name(aptr, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_HINFO:
/* The RR data is two length-counted character strings. */
p = aptr;
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s", name.as_char);
ares_free_string(name.as_char);
p += len;
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s", name.as_char);
ares_free_string(name.as_char);
break;
case T_MINFO:
/* The RR data is two domain names. */
p = aptr;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_MX:
/* The RR data is two bytes giving a preference ordering, and
* then a domain name.
*/
if (dlen < 2)
return NULL;
printf("\t%d", DNS__16BIT(aptr));
status = ares_expand_name(aptr + 2, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_SOA:
/* The RR data is two domain names and then five four-byte
* numbers giving the serial number and some timeouts.
*/
p = aptr;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s.\n", name.as_char);
ares_free_string(name.as_char);
p += len;
if (p + 20 > aptr + dlen)
return NULL;
printf("\t\t\t\t\t\t( %lu %lu %lu %lu %lu )",
(unsigned long)DNS__32BIT(p), (unsigned long)DNS__32BIT(p+4),
(unsigned long)DNS__32BIT(p+8), (unsigned long)DNS__32BIT(p+12),
(unsigned long)DNS__32BIT(p+16));
break;
case T_TXT:
/* The RR data is one or more length-counted character
* strings. */
p = aptr;
while (p < aptr + dlen)
{
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s", name.as_char);
ares_free_string(name.as_char);
p += len;
}
break;
case T_A:
/* The RR data is a four-byte Internet address. */
if (dlen != 4)
return NULL;
printf("\t%s", ares_inet_ntop(AF_INET,aptr,addr,sizeof(addr)));
break;
case T_AAAA:
/* The RR data is a 16-byte IPv6 address. */
if (dlen != 16)
return NULL;
printf("\t%s", ares_inet_ntop(AF_INET6,aptr,addr,sizeof(addr)));
break;
case T_WKS:
/* Not implemented yet */
break;
case T_SRV:
/* The RR data is three two-byte numbers representing the
* priority, weight, and port, followed by a domain name.
*/
printf("\t%d", DNS__16BIT(aptr));
printf(" %d", DNS__16BIT(aptr + 2));
printf(" %d", DNS__16BIT(aptr + 4));
status = ares_expand_name(aptr + 6, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_NAPTR:
printf("\t%d", DNS__16BIT(aptr)); /* order */
printf(" %d\n", DNS__16BIT(aptr + 2)); /* preference */
p = aptr + 4;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s", name.as_char);
ares_free_string(name.as_char);
break;
default:
printf("\t[Unknown RR; cannot parse]");
break;
}
printf("\n");
return aptr + dlen;
}
static int
ev_ares_parse_a_reply (const unsigned char *abuf, int alen,
struct ev_ares_a_reply **a_out)
{
unsigned int qdcount, ancount, i;
const unsigned char *aptr, *vptr;
int status, rr_type, rr_class, rr_len, rr_ttl, cname_ttl = INT_MAX;
int naddrs = 0, naliases = 0;
long len;
char *hostname = NULL, *rr_name = NULL, *rr_data = NULL;
struct ev_ares_a_reply *a_head = NULL;
struct ev_ares_a_reply *a_last = NULL;
struct ev_ares_a_reply *a_curr;
/* Set *a_out to NULL for all failure cases. */
*a_out = NULL;
/* Give up if abuf doesn't have room for a header. */
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* Fetch the question and answer count from the header. */
qdcount = DNS_HEADER_QDCOUNT (abuf);
ancount = DNS_HEADER_ANCOUNT (abuf);
if (qdcount != 1)
return ARES_EBADRESP;
if (ancount == 0)
return ARES_ENODATA;
/* Expand the name from the question, and skip past the question. */
aptr = abuf + HFIXEDSZ;
status = ares_expand_name (aptr, abuf, alen, &hostname, &len);
if (status != ARES_SUCCESS)
return status;
if (aptr + len + QFIXEDSZ > abuf + alen)
{
free (hostname);
return ARES_EBADRESP;
}
aptr += len + QFIXEDSZ;
/* Examine each answer resource record (RR) in turn. */
for (i = 0; i < ancount; i++)
{
/* Decode the RR up to the data field. */
status = ares_expand_name (aptr, abuf, alen, &rr_name, &len);
//cwarn("expanded name: %s",rr_name);
if (status != ARES_SUCCESS)
{
break;
}
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
rr_type = DNS_RR_TYPE (aptr);
rr_class = DNS_RR_CLASS (aptr);
rr_ttl = DNS_RR_TTL (aptr);
rr_len = DNS_RR_LEN (aptr);
aptr += RRFIXEDSZ;
if (aptr + rr_len > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
/* Check if we are really looking at a A record */
if (rr_class == C_IN && rr_type == T_A) {
if ( rr_len == sizeof(struct in_addr) && strcasecmp(rr_name, hostname) == 0 ) {
if (aptr + sizeof(struct in_addr) > abuf + alen) {
status = ARES_EBADRESP;
break;
}
a_curr = calloc(1,sizeof(struct ev_ares_a_reply));
if (!a_curr)
{
status = ARES_ENOMEM;
break;
}
if (a_last)
{
a_last->next = a_curr;
}
else
{
a_head = a_curr;
}
a_last = a_curr;
a_curr->ttl = rr_ttl;
a_curr->host = rr_name;
rr_name = NULL;
memcpy(&a_curr->ip, aptr, sizeof(struct in_addr));
naddrs++;
}
}
else
if (rr_class == C_IN && rr_type == T_CNAME) {
naliases++;
status = ares_expand_name(aptr, abuf, alen, &rr_data, &len);
if (status != ARES_SUCCESS)
break;
if (cname_ttl > rr_ttl)
cname_ttl = rr_ttl;
free(hostname);
hostname = rr_data;
}
if (rr_name)
free(rr_name);
rr_name = NULL;
/* Move on to the next record */
aptr += rr_len;
}
if (hostname)
free (hostname);
if (rr_name)
free (rr_name);
if (status == ARES_SUCCESS && naddrs == 0 && naliases == 0)
/* the check for naliases to be zero is to make sure CNAME responses
don't get caught here */
status = ARES_ENODATA;
/* clean up on error */
if (status == ARES_SUCCESS)
{
if (naliases > 0) {
for (a_curr = a_head;a_curr;a_curr = a_curr->next)
{
if (a_curr->ttl > cname_ttl)
a_curr->ttl = cname_ttl;
}
}
}
else
{
if (a_head)
ev_ares_free_a_reply (a_head);
return status;
}
/* everything looks fine, return the data */
*a_out = a_head;
return ARES_SUCCESS;
}
static const unsigned char *display_rr(const unsigned char *aptr,
const unsigned char *abuf, int alen,
dns_resp_t *response)
{
const unsigned char *p;
char *name;
int type, dnsclass, ttl, dlen, status;
long len;
struct in_addr addr;
/* Parse the RR name. */
status = ares_expand_name(aptr, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
aptr += len;
/* Make sure there is enough data after the RR name for the fixed
* part of the RR.
*/
if (aptr + RRFIXEDSZ > abuf + alen) {
xfree(name);
return NULL;
}
/* Parse the fixed part of the RR, and advance to the RR data field. */
type = DNS_RR_TYPE(aptr);
dnsclass = DNS_RR_CLASS(aptr);
ttl = DNS_RR_TTL(aptr);
dlen = DNS_RR_LEN(aptr);
aptr += RRFIXEDSZ;
if (aptr + dlen > abuf + alen) {
xfree(name);
return NULL;
}
/* Display the RR name, class, and type. */
sprintf(msg, "\t%-15s.\t%d", name, ttl);
addtobuffer(response->msgbuf, msg);
if (dnsclass != C_IN) {
sprintf(msg, "\t%s", class_name(dnsclass));
addtobuffer(response->msgbuf, msg);
}
sprintf(msg, "\t%s", type_name(type));
addtobuffer(response->msgbuf, msg);
xfree(name);
/* Display the RR data. Don't touch aptr. */
switch (type) {
case T_CNAME:
case T_MB:
case T_MD:
case T_MF:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
/* For these types, the RR data is just a domain name. */
status = ares_expand_name(aptr, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
break;
case T_HINFO:
/* The RR data is two length-counted character strings. */
p = aptr;
len = *p;
if (p + len + 1 > aptr + dlen) return NULL;
sprintf(msg, "\t%.*s", (int) len, p + 1);
addtobuffer(response->msgbuf, msg);
p += len + 1;
len = *p;
if (p + len + 1 > aptr + dlen) return NULL;
sprintf(msg, "\t%.*s", (int) len, p + 1);
addtobuffer(response->msgbuf, msg);
break;
case T_MINFO:
/* The RR data is two domain names. */
p = aptr;
status = ares_expand_name(p, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
p += len;
status = ares_expand_name(p, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
break;
case T_MX:
/* The RR data is two bytes giving a preference ordering, and then a domain name. */
if (dlen < 2) return NULL;
sprintf(msg, "\t%d", (aptr[0] << 8) | aptr[1]);
addtobuffer(response->msgbuf, msg);
status = ares_expand_name(aptr + 2, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
break;
case T_SOA:
/*
* The RR data is two domain names and then five four-byte
* numbers giving the serial number and some timeouts.
*/
p = aptr;
status = ares_expand_name(p, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.\n", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
p += len;
status = ares_expand_name(p, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t\t\t\t\t\t%s.\n", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
p += len;
if (p + 20 > aptr + dlen) return NULL;
sprintf(msg, "\t\t\t\t\t\t( %d %d %d %d %d )",
(p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3],
(p[4] << 24) | (p[5] << 16) | (p[6] << 8) | p[7],
(p[8] << 24) | (p[9] << 16) | (p[10] << 8) | p[11],
(p[12] << 24) | (p[13] << 16) | (p[14] << 8) | p[15],
(p[16] << 24) | (p[17] << 16) | (p[18] << 8) | p[19]);
addtobuffer(response->msgbuf, msg);
break;
case T_TXT:
/* The RR data is one or more length-counted character strings. */
p = aptr;
while (p < aptr + dlen) {
len = *p;
if (p + len + 1 > aptr + dlen) return NULL;
sprintf(msg, "\t%.*s", (int)len, p + 1);
addtobuffer(response->msgbuf, msg);
p += len + 1;
}
break;
case T_A:
/* The RR data is a four-byte Internet address. */
if (dlen != 4) return NULL;
memcpy(&addr, aptr, sizeof(struct in_addr));
sprintf(msg, "\t%s", inet_ntoa(addr));
addtobuffer(response->msgbuf, msg);
break;
case T_WKS:
/* Not implemented yet */
break;
case T_SRV:
/*
* The RR data is three two-byte numbers representing the
* priority, weight, and port, followed by a domain name.
*/
sprintf(msg, "\t%d", DNS__16BIT(aptr));
addtobuffer(response->msgbuf, msg);
sprintf(msg, " %d", DNS__16BIT(aptr + 2));
addtobuffer(response->msgbuf, msg);
sprintf(msg, " %d", DNS__16BIT(aptr + 4));
addtobuffer(response->msgbuf, msg);
status = ares_expand_name(aptr + 6, abuf, alen, &name, &len);
if (status != ARES_SUCCESS) return NULL;
sprintf(msg, "\t%s.", name);
addtobuffer(response->msgbuf, msg);
xfree(name);
break;
default:
sprintf(msg, "\t[Unknown RR; cannot parse]");
addtobuffer(response->msgbuf, msg);
}
sprintf(msg, "\n");
addtobuffer(response->msgbuf, msg);
return aptr + dlen;
}
int LLQueryResponder::parseRR(const char *buf, size_t len, const char *&pos,
LLPointer<LLDnsRecord> &r)
{
std::string rrname;
size_t enclen;
int ret;
// RR name.
ret = LLAres::expandName(pos, buf, len, rrname, enclen);
if (ret != ARES_SUCCESS)
{
return ret;
}
pos += enclen;
if (pos + NS_RRFIXEDSZ > buf + len)
{
return ARES_EBADRESP;
}
int rrtype = DNS_RR_TYPE(pos);
int rrclass = DNS_RR_CLASS(pos);
int rrttl = DNS_RR_TTL(pos);
int rrlen = DNS_RR_LEN(pos);
if (rrclass != ns_c_in)
{
return ARES_EBADRESP;
}
pos += NS_RRFIXEDSZ;
if (pos + rrlen > buf + len)
{
return ARES_EBADRESP;
}
switch (rrtype)
{
case RES_A:
r = new LLARecord(rrname, rrttl);
break;
case RES_NS:
r = new LLNsRecord(rrname, rrttl);
break;
case RES_CNAME:
r = new LLCnameRecord(rrname, rrttl);
break;
case RES_PTR:
r = new LLPtrRecord(rrname, rrttl);
break;
case RES_AAAA:
r = new LLAaaaRecord(rrname, rrttl);
break;
case RES_SRV:
r = new LLSrvRecord(rrname, rrttl);
break;
default:
LL_INFOS() << "LLQueryResponder::parseRR got unknown RR type " << rrtype
<< LL_ENDL;
return ARES_EBADRESP;
}
ret = r->parse(buf, len, pos, rrlen);
if (ret == ARES_SUCCESS)
{
pos += rrlen;
} else {
r = NULL;
}
return ret;
}
int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
struct hostent **host, struct ares_addr6ttl *addrttls,
int *naddrttls)
{
unsigned int qdcount, ancount;
int status, i, rr_type, rr_class, rr_len, rr_ttl, naddrs;
int cname_ttl = INT_MAX; /* the TTL imposed by the CNAME chain */
int naliases;
long len;
const unsigned char *aptr;
char *hostname, *rr_name, *rr_data, **aliases;
struct ares_in6_addr *addrs;
struct hostent *hostent;
const int max_addr_ttls = (addrttls && naddrttls) ? *naddrttls : 0;
/* Set *host to NULL for all failure cases. */
if (host)
*host = NULL;
/* Same with *naddrttls. */
if (naddrttls)
*naddrttls = 0;
/* Give up if abuf doesn't have room for a header. */
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* Fetch the question and answer count from the header. */
qdcount = DNS_HEADER_QDCOUNT(abuf);
ancount = DNS_HEADER_ANCOUNT(abuf);
if (qdcount != 1)
return ARES_EBADRESP;
/* Expand the name from the question, and skip past the question. */
aptr = abuf + HFIXEDSZ;
status = ares__expand_name_for_response(aptr, abuf, alen, &hostname, &len);
if (status != ARES_SUCCESS)
return status;
if (aptr + len + QFIXEDSZ > abuf + alen)
{
free(hostname);
return ARES_EBADRESP;
}
aptr += len + QFIXEDSZ;
/* Allocate addresses and aliases; ancount gives an upper bound for both. */
if (host)
{
addrs = malloc(ancount * sizeof(struct ares_in6_addr));
if (!addrs)
{
free(hostname);
return ARES_ENOMEM;
}
aliases = malloc((ancount + 1) * sizeof(char *));
if (!aliases)
{
free(hostname);
free(addrs);
return ARES_ENOMEM;
}
}
else
{
addrs = NULL;
aliases = NULL;
}
naddrs = 0;
naliases = 0;
/* Examine each answer resource record (RR) in turn. */
for (i = 0; i < (int)ancount; i++)
{
/* Decode the RR up to the data field. */
status = ares__expand_name_for_response(aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
break;
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
rr_type = DNS_RR_TYPE(aptr);
rr_class = DNS_RR_CLASS(aptr);
rr_len = DNS_RR_LEN(aptr);
rr_ttl = DNS_RR_TTL(aptr);
aptr += RRFIXEDSZ;
if (rr_class == C_IN && rr_type == T_AAAA
&& rr_len == sizeof(struct ares_in6_addr)
&& strcasecmp(rr_name, hostname) == 0)
{
if (addrs)
{
if (aptr + sizeof(struct ares_in6_addr) > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
memcpy(&addrs[naddrs], aptr, sizeof(struct ares_in6_addr));
}
if (naddrs < max_addr_ttls)
{
struct ares_addr6ttl * const at = &addrttls[naddrs];
if (aptr + sizeof(struct ares_in6_addr) > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
memcpy(&at->ip6addr, aptr, sizeof(struct ares_in6_addr));
at->ttl = rr_ttl;
}
naddrs++;
status = ARES_SUCCESS;
}
if (rr_class == C_IN && rr_type == T_CNAME)
{
/* Record the RR name as an alias. */
if (aliases)
aliases[naliases] = rr_name;
else
free(rr_name);
naliases++;
/* Decode the RR data and replace the hostname with it. */
status = ares__expand_name_for_response(aptr, abuf, alen, &rr_data,
&len);
if (status != ARES_SUCCESS)
break;
free(hostname);
hostname = rr_data;
/* Take the min of the TTLs we see in the CNAME chain. */
if (cname_ttl > rr_ttl)
cname_ttl = rr_ttl;
}
else
free(rr_name);
aptr += rr_len;
if (aptr > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
}
if (status == ARES_SUCCESS && naddrs == 0)
status = ARES_ENODATA;
if (status == ARES_SUCCESS)
{
/* We got our answer. */
if (naddrttls)
{
const int n = naddrs < max_addr_ttls ? naddrs : max_addr_ttls;
for (i = 0; i < n; i++)
{
/* Ensure that each A TTL is no larger than the CNAME TTL. */
if (addrttls[i].ttl > cname_ttl)
addrttls[i].ttl = cname_ttl;
}
*naddrttls = n;
}
if (aliases)
aliases[naliases] = NULL;
if (host)
{
/* Allocate memory to build the host entry. */
hostent = malloc(sizeof(struct hostent));
if (hostent)
{
hostent->h_addr_list = malloc((naddrs + 1) * sizeof(char *));
if (hostent->h_addr_list)
{
/* Fill in the hostent and return successfully. */
hostent->h_name = hostname;
hostent->h_aliases = aliases;
hostent->h_addrtype = AF_INET6;
hostent->h_length = sizeof(struct ares_in6_addr);
for (i = 0; i < naddrs; i++)
hostent->h_addr_list[i] = (char *) &addrs[i];
hostent->h_addr_list[naddrs] = NULL;
*host = hostent;
return ARES_SUCCESS;
}
free(hostent);
}
status = ARES_ENOMEM;
}
}
if (aliases)
{
for (i = 0; i < naliases; i++)
free(aliases[i]);
free(aliases);
}
free(addrs);
free(hostname);
return status;
}
/* 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;
}
int
ares_parse_soa_reply(const unsigned char *abuf, int alen,
struct ares_soa_reply **soa_out)
{
const unsigned char *aptr;
long len;
char *qname = NULL, *rr_name = NULL;
struct ares_soa_reply *soa = NULL;
int qdcount, ancount;
int status;
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* parse message header */
qdcount = DNS_HEADER_QDCOUNT(abuf);
ancount = DNS_HEADER_ANCOUNT(abuf);
if (qdcount != 1 || ancount != 1)
return ARES_EBADRESP;
aptr = abuf + HFIXEDSZ;
/* query name */
status = ares__expand_name_for_response(aptr, abuf, alen, &qname, &len);
if (status != ARES_SUCCESS)
goto failed_stat;
aptr += len;
/* skip qtype & qclass */
if (aptr + QFIXEDSZ > abuf + alen)
goto failed;
aptr += QFIXEDSZ;
/* rr_name */
status = ares__expand_name_for_response(aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
goto failed_stat;
aptr += len;
/* allocate result struct */
soa = ares_malloc_data(ARES_DATATYPE_SOA_REPLY);
if (!soa)
{
status = ARES_ENOMEM;
goto failed_stat;
}
/* skip rr_type, rr_class, rr_ttl, rr_rdlen */
if (aptr + RRFIXEDSZ > abuf + alen)
goto failed;
soa->ttl = DNS_RR_TTL(aptr);
aptr += RRFIXEDSZ;
/* nsname */
status = ares__expand_name_for_response(aptr, abuf, alen, &soa->nsname, &len);
if (status != ARES_SUCCESS)
goto failed_stat;
aptr += len;
/* hostmaster */
status = ares__expand_name_for_response(aptr, abuf, alen, &soa->hostmaster, &len);
if (status != ARES_SUCCESS)
goto failed_stat;
aptr += len;
/* integer fields */
if (aptr + 5 * 4 > abuf + alen)
goto failed;
soa->serial = DNS__32BIT(aptr + 0 * 4);
soa->refresh = DNS__32BIT(aptr + 1 * 4);
soa->retry = DNS__32BIT(aptr + 2 * 4);
soa->expire = DNS__32BIT(aptr + 3 * 4);
soa->minttl = DNS__32BIT(aptr + 4 * 4);
ares_free(qname);
ares_free(rr_name);
*soa_out = soa;
return ARES_SUCCESS;
failed:
status = ARES_EBADRESP;
failed_stat:
ares_free_data(soa);
if (qname)
ares_free(qname);
if (rr_name)
ares_free(rr_name);
return status;
}
inline static const unsigned char *CheckPatternAfterParseAnswer(struct DNSTask *dnstask, const unsigned char *aptr, const unsigned char *abuf, int alen) {
const unsigned char *p;
int type, dnsclass, ttl, dlen, status;
long len;
char addr[46];
/*
if (task->LObjId == 1148) raise(SIGTRAP);
*/
union {
unsigned char * as_uchar;
char * as_char;
} name;
status = ares_expand_name(aptr, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen) {
ares_free_string(name.as_char);
return NULL;
}
type = DNS_RR_TYPE(aptr);
dnsclass = DNS_RR_CLASS(aptr);
ttl = DNS_RR_TTL(aptr);
dlen = DNS_RR_LEN(aptr);
aptr += RRFIXEDSZ;
if (aptr + dlen > abuf + alen) {
ares_free_string(name.as_char);
return NULL;
}
ares_free_string(name.as_char);
switch (type) {
case T_CNAME:
case T_MB:
case T_MD:
case T_MF:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
status = ares_expand_name(aptr, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS) {
debug("error T_%s compare, %s andd ttl %d error - %d", type_name(type), dnstask->taskPattern, dnstask->taskTTL, status);
return NULL;
}
debug("T_%s compare, %s:%08x on %s and ttl %d on %d", type_name(type), dnstask->taskPattern, dnstask->taskPattern, name.as_char, ttl, dnstask->taskTTL);
if ((dnstask->taskPattern[0] == 0 or !memcmp(name.as_char, dnstask->taskPattern, dnstask->taskPatternLen)) and(dnstask->taskTTL == 0 or ttl == dnstask->taskTTL)) {
dnstask->task->code = STATE_DONE;
}
ares_free_string(name.as_char);
break;
case T_HINFO:
/* The RR data is two length-counted character strings. */
p = aptr;
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
debug("\t%.*s", (int) len, p + 1);
p += len + 1;
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
debug("\t%.*s", (int) len, p + 1);
break;
case T_MINFO:
/* The RR data is two domain names. */
p = aptr;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
debug("\t%s.", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
debug("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_MX:
if (dlen < 2) {
return NULL;
}
status = ares_expand_name(aptr + 2, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS) {
return NULL;
}
debug("T_MX compare %s on %s and ttl %d on %d\n", dnstask->taskPattern, name.as_char, ttl, dnstask->taskTTL);
if ((dnstask->taskPattern[0] = 0 or !memcmp(name.as_char, dnstask->taskPattern, dnstask->taskPatternLen)) and(dnstask->taskTTL == 0 or ttl == dnstask->taskTTL)) {
dnstask->task->code = STATE_DONE;
}
ares_free_string(name.as_char);
break;
case T_SOA:
/* The RR data is two domain names and then five four-byte
* numbers giving the serial number and some timeouts.
*/
p = aptr;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
debug("\t%s.", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
debug("\t\t\t\t\t\t%s.", name.as_char);
ares_free_string(name.as_char);
p += len;
if (p + 20 > aptr + dlen)
return NULL;
debug("\t\t\t\t\t\t( %lu %lu %lu %lu %lu )",
(unsigned long) DNS__32BIT(p), (unsigned long) DNS__32BIT(p + 4),
(unsigned long) DNS__32BIT(p + 8), (unsigned long) DNS__32BIT(p + 12),
(unsigned long) DNS__32BIT(p + 16));
break;
case T_TXT:
/* The RR data is one or more length-counted character
* strings. */
p = aptr;
while (p < aptr + dlen) {
len = *p;
if (p + len + 1 > aptr + dlen)
return NULL;
//printf("\t%.*s", (int) len, p + 1);
debug("T_TXT compare %s on %s and ttl %d on %d", dnstask->taskPattern, p + 1, ttl, dnstask->taskTTL);
if (!memcmp(p + 1, dnstask->taskPattern, dnstask->taskPatternLen) and ttl == dnstask->taskTTL) {
dnstask->task->code = STATE_DONE;
}
p += len + 1;
}
break;
case T_A:
/* The RR data is a four-byte Internet address. */
inet_ntop(AF_INET, aptr, addr, sizeof (addr));
debug("T_A compare %s on %s (size %d) and ttl %d on %d", dnstask->taskPattern, addr, dnstask->taskPatternLen, ttl, dnstask->taskTTL);
/*
if (dnstask->task->LObjId == 1056) raise(SIGSEGV);
*/
if (dlen == 4 and(dnstask->taskPattern[0] == 0 or !memcmp(addr, dnstask->taskPattern, dnstask->taskPatternLen)) and(dnstask->taskTTL == 0 or ttl == dnstask->taskTTL)) {
dnstask->task->code = STATE_DONE;
}
break;
case T_AAAA:
/* The RR data is a 16-byte IPv6 address. */
if (dlen != 16)
return NULL;
debug("\t%s", inet_ntop(AF_INET6, aptr, addr, sizeof (addr)));
break;
case T_WKS:
/* Not implemented yet */
break;
case T_SRV:
/* The RR data is three two-byte numbers representing the
* priority, weight, and port, followed by a domain name.
*/
printf("\t%d", DNS__16BIT(aptr));
printf(" %d", DNS__16BIT(aptr + 2));
printf(" %d", DNS__16BIT(aptr + 4));
status = ares_expand_name(aptr + 6, abuf, alen, &name.as_char, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t%s.", name.as_char);
ares_free_string(name.as_char);
break;
case T_NAPTR:
printf("\t%d", DNS__16BIT(aptr)); /* order */
printf(" %d\n", DNS__16BIT(aptr + 2)); /* preference */
p = aptr + 4;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s\n", name.as_char);
ares_free_string(name.as_char);
p += len;
status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
if (status != ARES_SUCCESS)
return NULL;
printf("\t\t\t\t\t\t%s", name.as_char);
ares_free_string(name.as_char);
break;
default:
printf("\t[Unknown RR; cannot parse]");
break;
}
if (dnstask->task->code != STATE_DONE) {
return aptr + dlen;
} else {
return NULL;
}
}
static int
ev_ares_parse_ptr_reply (const unsigned char *abuf, int alen,
struct ev_ares_ptr_reply **ptr_out)
{
unsigned int qdcount, ancount, i;
const unsigned char *aptr, *vptr;
int status, rr_type, rr_class, rr_len, rr_ttl;
long len;
char *hostname = NULL, *rr_name = NULL;
struct ev_ares_ptr_reply *ptr_head = NULL;
struct ev_ares_ptr_reply *ptr_last = NULL;
struct ev_ares_ptr_reply *ptr_curr;
/* Set *ptr_out to NULL for all failure cases. */
*ptr_out = NULL;
/* Give up if abuf doesn't have room for a header. */
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* Fetch the question and answer count from the header. */
qdcount = DNS_HEADER_QDCOUNT (abuf);
ancount = DNS_HEADER_ANCOUNT (abuf);
if (qdcount != 1)
return ARES_EBADRESP;
if (ancount == 0)
return ARES_ENODATA;
/* Expand the name from the question, and skip past the question. */
aptr = abuf + HFIXEDSZ;
status = ares_expand_name (aptr, abuf, alen, &hostname, &len);
if (status != ARES_SUCCESS)
return status;
if (aptr + len + QFIXEDSZ > abuf + alen)
{
free (hostname);
return ARES_EBADRESP;
}
aptr += len + QFIXEDSZ;
/* Examine each answer resource record (RR) in turn. */
for (i = 0; i < ancount; i++)
{
/* Decode the RR up to the data field. */
status = ares_expand_name (aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
{
break;
}
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
rr_type = DNS_RR_TYPE (aptr);
rr_class = DNS_RR_CLASS (aptr);
rr_ttl = DNS_RR_TTL (aptr);
rr_len = DNS_RR_LEN (aptr);
aptr += RRFIXEDSZ;
if (aptr + rr_len > abuf + alen)
{
status = ARES_EBADRESP;
break;
}
/* Check if we are really looking at a ns record */
if (rr_class == C_IN && rr_type == T_PTR)
{
/* parse the NS record itself */
if (rr_len < 2)
{
status = ARES_EBADRESP;
break;
}
/* Allocate storage for this MX answer appending it to the list */
ptr_curr = calloc(1,sizeof(struct ev_ares_ptr_reply));
if (!ptr_curr)
{
status = ARES_ENOMEM;
break;
}
if (ptr_last)
{
ptr_last->next = ptr_curr;
}
else
{
ptr_head = ptr_curr;
}
ptr_last = ptr_curr;
ptr_curr->ttl = rr_ttl;
vptr = aptr;
status = ares_expand_name (vptr, abuf, alen, &ptr_curr->host, &len);
if (status != ARES_SUCCESS)
break;
}
/* Don't lose memory in the next iteration */
free (rr_name);
rr_name = NULL;
/* Move on to the next record */
aptr += rr_len;
}
if (hostname)
free (hostname);
if (rr_name)
free (rr_name);
/* clean up on error */
if (status != ARES_SUCCESS)
{
if (ptr_head)
ev_ares_free_ptr_reply(ptr_head);
return status;
}
/* everything looks fine, return the data */
*ptr_out = ptr_head;
return ARES_SUCCESS;
}