int Resolver :: ar_procanswer(DNSSession* session, HEADER* hptr, u_char* buf, u_char* eob)
{
u_char* cp = NULL;
char** alias = NULL;
int xclass, type = 0, dlen, len, ans = 0, n = 0;
char** adr = NULL;
char ar_hostbuf[MAXDNAME]; /* Must be on stack */
unsigned int ancount = 0 , arcount = 0 , nscount = 0, qdcount = 0;
int host_cnt = 0;
/*
* convert things to be in the right order.
*/
ancount = ntohs(hptr->ancount);
arcount = ntohs(hptr->arcount);
nscount = ntohs(hptr->nscount);
qdcount = ntohs(hptr->qdcount);
cp = buf + HFIXEDSZ;
hent& re_he = session->getHent();
adr = re_he.h_addr_list;
#ifdef DNS_DEBUG
Print_query(buf, eob, 1);
#endif
while (*adr)
{
adr++;
host_cnt++;
}
alias = re_he.h_aliases;
while (*alias)
{
alias++;
}
/*
* Skip over the original question.
*/
while (qdcount > 0)
{
qdcount--;
cp += dn_skipname((const unsigned char*)cp, (const unsigned char*)eob) + QFIXEDSZ;
}
/*
* process each answer sent to us. blech.
*/
while ((ancount > 0) && (cp < eob))
{
ancount--;
PR_Lock(dnslock);
n = dn_expand((const unsigned char*)buf, (const unsigned char*)eob, (const unsigned char*)cp, (char*)ar_hostbuf, sizeof(ar_hostbuf));
PR_Unlock(dnslock);
cp += n;
if (n <= 0)
return ans;
ans++;
/*
* 'skip' past the general dns crap (ttl, xclass, etc) to get
* the pointer to the right spot. Some of thse are actually
* useful so its not a good idea to skip past in one big jump.
*/
type = (int)GetShort(cp);
cp += sizeof(short);
xclass = (int)GetShort(cp);
cp += sizeof(short);
/* ttl = */ (void)(PRUint32)GetLong(cp);
cp += INT32SZ;
dlen = (int)GetShort(cp);
cp += sizeof(short);
session->setType(type);
switch(type)
{
case T_A :
{
re_he.h_addrtype = PR_AF_INET;
re_he.h_length = INADDRSZ;
re_he.h_addr_list[host_cnt] = (char *)malloc(INADDRSZ);
memcpy(re_he.h_addr_list[host_cnt], cp, dlen);
re_he.h_addr_list[++host_cnt] = NULL;
cp += dlen;
len = strlen(ar_hostbuf);
if (!re_he.h_name)
{
re_he.h_name = (char *)malloc(len+1);
(void)strcpy(re_he.h_name, ar_hostbuf);
}
break;
}
case T_AAAA :
{
char buf[1024];
re_he.h_addrtype = PR_AF_INET6;
re_he.h_length = IN6ADDRSZ;
re_he.h_addr_list[host_cnt] = (char *)malloc(16);
memcpy(re_he.h_addr_list[host_cnt], cp, dlen);
re_he.h_addr_list[++host_cnt] = NULL;
cp += dlen;
len = strlen(ar_hostbuf);
if (!re_he.h_name)
{
re_he.h_name = (char *)malloc(len+1);
(void)strcpy(re_he.h_name, ar_hostbuf);
}
break;
}
case T_PTR :
{
PR_Lock(dnslock);
n = dn_expand((const unsigned char*)buf, (const unsigned char*)eob, (const unsigned char*)cp, (char*)ar_hostbuf, sizeof(ar_hostbuf));
PR_Unlock(dnslock);
if (n < 0)
{
cp += n;
continue;
}
cp += n;
len = strlen(ar_hostbuf)+1;
/*
* copy the returned hostname into the host name
* or alias field if there is a known hostname
* already.
*/
if (!re_he.h_name)
{
re_he.h_name = (char *)malloc(len);
(void)strcpy(re_he.h_name, ar_hostbuf);
}
else
{
*alias = (char*)malloc(len);
if (!*alias)
return -1;
(void)strcpy(*alias++, ar_hostbuf);
*alias = NULL;
}
break;
}
case T_CNAME :
{
cp += dlen;
if (alias >= &(re_he.h_aliases[MAXALIASES-1]))
continue;
n = strlen(ar_hostbuf)+1;
*alias = (char*)malloc(n);
if (!*alias)
return -1;
(void)strcpy(*alias++, ar_hostbuf);
*alias = NULL;
break;
}
default :
{
break;
}
}
}
return ans;
}
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;
}