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samba-mirror/source3/libaddns/dnssock.c
Volker Lendecke 7215b1f69a Fix an uninitialized variable, Coverity ID 481
(This used to be commit 9e4f576abf)
2008-03-06 11:47:31 +01:00

378 lines
8.5 KiB
C

/*
Linux DNS client library implementation
Copyright (C) 2006 Krishna Ganugapati <krishnag@centeris.com>
Copyright (C) 2006 Gerald Carter <jerry@samba.org>
** NOTE! The following LGPL license applies to the libaddns
** library. This does NOT imply that all of Samba is released
** under the LGPL
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "dns.h"
#include <sys/time.h>
#include <unistd.h>
static int destroy_dns_connection(struct dns_connection *conn)
{
return close(conn->s);
}
/********************************************************************
********************************************************************/
static DNS_ERROR dns_tcp_open( const char *nameserver,
TALLOC_CTX *mem_ctx,
struct dns_connection **result )
{
uint32_t ulAddress;
struct hostent *pHost;
struct sockaddr_in s_in;
struct dns_connection *conn;
int res;
if (!(conn = talloc(mem_ctx, struct dns_connection))) {
return ERROR_DNS_NO_MEMORY;
}
if ( (ulAddress = inet_addr( nameserver )) == INADDR_NONE ) {
if ( (pHost = gethostbyname( nameserver )) == NULL ) {
TALLOC_FREE(conn);
return ERROR_DNS_INVALID_NAME_SERVER;
}
memcpy( &ulAddress, pHost->h_addr, pHost->h_length );
}
conn->s = socket( PF_INET, SOCK_STREAM, 0 );
if (conn->s == -1) {
TALLOC_FREE(conn);
return ERROR_DNS_CONNECTION_FAILED;
}
talloc_set_destructor(conn, destroy_dns_connection);
s_in.sin_family = AF_INET;
s_in.sin_addr.s_addr = ulAddress;
s_in.sin_port = htons( DNS_TCP_PORT );
res = connect(conn->s, (struct sockaddr*)&s_in, sizeof( s_in ));
if (res == -1) {
TALLOC_FREE(conn);
return ERROR_DNS_CONNECTION_FAILED;
}
conn->hType = DNS_TCP;
*result = conn;
return ERROR_DNS_SUCCESS;
}
/********************************************************************
********************************************************************/
static DNS_ERROR dns_udp_open( const char *nameserver,
TALLOC_CTX *mem_ctx,
struct dns_connection **result )
{
unsigned long ulAddress;
struct hostent *pHost;
struct sockaddr_in RecvAddr;
struct dns_connection *conn;
if (!(conn = talloc(NULL, struct dns_connection))) {
return ERROR_DNS_NO_MEMORY;
}
if ( (ulAddress = inet_addr( nameserver )) == INADDR_NONE ) {
if ( (pHost = gethostbyname( nameserver )) == NULL ) {
TALLOC_FREE(conn);
return ERROR_DNS_INVALID_NAME_SERVER;
}
memcpy( &ulAddress, pHost->h_addr, pHost->h_length );
}
/* Create a socket for sending data */
conn->s = socket( AF_INET, SOCK_DGRAM, IPPROTO_UDP );
if (conn->s == -1) {
TALLOC_FREE(conn);
return ERROR_DNS_CONNECTION_FAILED;
}
talloc_set_destructor(conn, destroy_dns_connection);
/* Set up the RecvAddr structure with the IP address of
the receiver (in this example case "123.456.789.1")
and the specified port number. */
ZERO_STRUCT(RecvAddr);
RecvAddr.sin_family = AF_INET;
RecvAddr.sin_port = htons( DNS_UDP_PORT );
RecvAddr.sin_addr.s_addr = ulAddress;
conn->hType = DNS_UDP;
memcpy( &conn->RecvAddr, &RecvAddr, sizeof( struct sockaddr_in ) );
*result = conn;
return ERROR_DNS_SUCCESS;
}
/********************************************************************
********************************************************************/
DNS_ERROR dns_open_connection( const char *nameserver, int32 dwType,
TALLOC_CTX *mem_ctx,
struct dns_connection **conn )
{
switch ( dwType ) {
case DNS_TCP:
return dns_tcp_open( nameserver, mem_ctx, conn );
case DNS_UDP:
return dns_udp_open( nameserver, mem_ctx, conn );
}
return ERROR_DNS_INVALID_PARAMETER;
}
static DNS_ERROR write_all(int fd, uint8 *data, size_t len)
{
size_t total = 0;
while (total < len) {
ssize_t ret = write(fd, data + total, len - total);
if (ret <= 0) {
/*
* EOF or error
*/
return ERROR_DNS_SOCKET_ERROR;
}
total += ret;
}
return ERROR_DNS_SUCCESS;
}
static DNS_ERROR dns_send_tcp(struct dns_connection *conn,
const struct dns_buffer *buf)
{
uint16 len = htons(buf->offset);
DNS_ERROR err;
err = write_all(conn->s, (uint8 *)&len, sizeof(len));
if (!ERR_DNS_IS_OK(err)) return err;
return write_all(conn->s, buf->data, buf->offset);
}
static DNS_ERROR dns_send_udp(struct dns_connection *conn,
const struct dns_buffer *buf)
{
ssize_t ret;
ret = sendto(conn->s, buf->data, buf->offset, 0,
(struct sockaddr *)&conn->RecvAddr,
sizeof(conn->RecvAddr));
if (ret != buf->offset) {
return ERROR_DNS_SOCKET_ERROR;
}
return ERROR_DNS_SUCCESS;
}
DNS_ERROR dns_send(struct dns_connection *conn, const struct dns_buffer *buf)
{
if (conn->hType == DNS_TCP) {
return dns_send_tcp(conn, buf);
}
if (conn->hType == DNS_UDP) {
return dns_send_udp(conn, buf);
}
return ERROR_DNS_INVALID_PARAMETER;
}
static DNS_ERROR read_all(int fd, uint8 *data, size_t len)
{
size_t total = 0;
fd_set rfds;
struct timeval tv;
while (total < len) {
ssize_t ret;
int fd_ready;
FD_ZERO( &rfds );
FD_SET( fd, &rfds );
/* 10 second timeout */
tv.tv_sec = 10;
tv.tv_usec = 0;
fd_ready = select( fd+1, &rfds, NULL, NULL, &tv );
if ( fd_ready == 0 ) {
/* read timeout */
return ERROR_DNS_SOCKET_ERROR;
}
ret = read(fd, data + total, len - total);
if (ret <= 0) {
/* EOF or error */
return ERROR_DNS_SOCKET_ERROR;
}
total += ret;
}
return ERROR_DNS_SUCCESS;
}
static DNS_ERROR dns_receive_tcp(TALLOC_CTX *mem_ctx,
struct dns_connection *conn,
struct dns_buffer **presult)
{
struct dns_buffer *buf;
DNS_ERROR err;
uint16 len;
if (!(buf = TALLOC_ZERO_P(mem_ctx, struct dns_buffer))) {
return ERROR_DNS_NO_MEMORY;
}
err = read_all(conn->s, (uint8 *)&len, sizeof(len));
if (!ERR_DNS_IS_OK(err)) {
return err;
}
buf->size = ntohs(len);
if (buf->size) {
if (!(buf->data = TALLOC_ARRAY(buf, uint8, buf->size))) {
TALLOC_FREE(buf);
return ERROR_DNS_NO_MEMORY;
}
} else {
buf->data = NULL;
}
err = read_all(conn->s, buf->data, buf->size);
if (!ERR_DNS_IS_OK(err)) {
TALLOC_FREE(buf);
return err;
}
*presult = buf;
return ERROR_DNS_SUCCESS;
}
static DNS_ERROR dns_receive_udp(TALLOC_CTX *mem_ctx,
struct dns_connection *conn,
struct dns_buffer **presult)
{
struct dns_buffer *buf;
ssize_t received;
if (!(buf = TALLOC_ZERO_P(mem_ctx, struct dns_buffer))) {
return ERROR_DNS_NO_MEMORY;
}
/*
* UDP based DNS can only be 512 bytes
*/
if (!(buf->data = TALLOC_ARRAY(buf, uint8, 512))) {
TALLOC_FREE(buf);
return ERROR_DNS_NO_MEMORY;
}
received = recv(conn->s, (void *)buf->data, 512, 0);
if (received == -1) {
TALLOC_FREE(buf);
return ERROR_DNS_SOCKET_ERROR;
}
if (received > 512) {
TALLOC_FREE(buf);
return ERROR_DNS_BAD_RESPONSE;
}
buf->size = received;
buf->offset = 0;
*presult = buf;
return ERROR_DNS_SUCCESS;
}
DNS_ERROR dns_receive(TALLOC_CTX *mem_ctx, struct dns_connection *conn,
struct dns_buffer **presult)
{
if (conn->hType == DNS_TCP) {
return dns_receive_tcp(mem_ctx, conn, presult);
}
if (conn->hType == DNS_UDP) {
return dns_receive_udp(mem_ctx, conn, presult);
}
return ERROR_DNS_INVALID_PARAMETER;
}
DNS_ERROR dns_transaction(TALLOC_CTX *mem_ctx, struct dns_connection *conn,
const struct dns_request *req,
struct dns_request **resp)
{
struct dns_buffer *buf = NULL;
DNS_ERROR err;
err = dns_marshall_request(conn, req, &buf);
if (!ERR_DNS_IS_OK(err)) goto error;
err = dns_send(conn, buf);
if (!ERR_DNS_IS_OK(err)) goto error;
TALLOC_FREE(buf);
err = dns_receive(mem_ctx, conn, &buf);
if (!ERR_DNS_IS_OK(err)) goto error;
err = dns_unmarshall_request(mem_ctx, buf, resp);
error:
TALLOC_FREE(buf);
return err;
}
DNS_ERROR dns_update_transaction(TALLOC_CTX *mem_ctx,
struct dns_connection *conn,
struct dns_update_request *up_req,
struct dns_update_request **up_resp)
{
struct dns_request *resp;
DNS_ERROR err;
err = dns_transaction(mem_ctx, conn, dns_update2request(up_req),
&resp);
if (!ERR_DNS_IS_OK(err)) return err;
*up_resp = dns_request2update(resp);
return ERROR_DNS_SUCCESS;
}