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samba-mirror/source4/lib/stream/packet.c
2007-10-10 13:46:03 -05:00

485 lines
11 KiB
C

/*
Unix SMB/CIFS mplementation.
helper layer for breaking up streams into discrete requests
Copyright (C) Andrew Tridgell 2005
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
#include "dlinklist.h"
#include "lib/events/events.h"
#include "lib/socket/socket.h"
#include "lib/tls/tls.h"
#include "lib/stream/packet.h"
struct packet_context {
packet_callback_fn_t callback;
packet_full_request_fn_t full_request;
packet_error_handler_fn_t error_handler;
DATA_BLOB partial;
uint32_t num_read;
uint32_t initial_read;
struct tls_context *tls;
struct socket_context *sock;
struct event_context *ev;
size_t packet_size;
void *private;
struct fd_event *fde;
BOOL serialise;
BOOL processing;
BOOL recv_disable;
BOOL nofree;
struct send_element {
struct send_element *next, *prev;
DATA_BLOB blob;
size_t nsent;
} *send_queue;
};
/*
initialise a packet receiver
*/
struct packet_context *packet_init(TALLOC_CTX *mem_ctx)
{
return talloc_zero(mem_ctx, struct packet_context);
}
/*
set the request callback, called when a full request is ready
*/
void packet_set_callback(struct packet_context *pc, packet_callback_fn_t callback)
{
pc->callback = callback;
}
/*
set the error handler
*/
void packet_set_error_handler(struct packet_context *pc, packet_error_handler_fn_t handler)
{
pc->error_handler = handler;
}
/*
set the private pointer passed to the callback functions
*/
void packet_set_private(struct packet_context *pc, void *private)
{
pc->private = private;
}
/*
set the full request callback. Should return as follows:
NT_STATUS_OK == blob is a full request.
STATUS_MORE_ENTRIES == blob is not complete yet
any error == blob is not a valid
*/
void packet_set_full_request(struct packet_context *pc, packet_full_request_fn_t callback)
{
pc->full_request = callback;
}
/*
set a tls context to use. You must either set a tls_context or a socket_context
*/
void packet_set_tls(struct packet_context *pc, struct tls_context *tls)
{
pc->tls = tls;
}
/*
set a socket context to use. You must either set a tls_context or a socket_context
*/
void packet_set_socket(struct packet_context *pc, struct socket_context *sock)
{
pc->sock = sock;
}
/*
set an event context. If this is set then the code will ensure that
packets arrive with separate events, by creating a immediate event
for any secondary packets when more than one packet is read at one
time on a socket. This can matter for code that relies on not
getting more than one packet per event
*/
void packet_set_event_context(struct packet_context *pc, struct event_context *ev)
{
pc->ev = ev;
}
/*
tell the packet layer to serialise requests, so we don't process two requests at once on
one connection. You must have set the event_context
*/
void packet_set_serialise(struct packet_context *pc, struct fd_event *fde)
{
pc->serialise = True;
pc->fde = fde;
}
/*
tell the packet layer how much to read when starting a new packet
this ensures it doesn't overread
*/
void packet_set_initial_read(struct packet_context *pc, uint32_t initial_read)
{
pc->initial_read = initial_read;
}
/*
tell the packet system not to steal/free blobs given to packet_send()
*/
void packet_set_nofree(struct packet_context *pc)
{
pc->nofree = True;
}
/*
tell the caller we have an error
*/
static void packet_error(struct packet_context *pc, NTSTATUS status)
{
pc->tls = NULL;
pc->sock = NULL;
if (pc->error_handler) {
pc->error_handler(pc->private, status);
return;
}
/* default error handler is to free the callers private pointer */
if (!NT_STATUS_EQUAL(status, NT_STATUS_END_OF_FILE)) {
DEBUG(0,("packet_error on %s - %s\n",
talloc_get_name(pc->private), nt_errstr(status)));
}
talloc_free(pc->private);
return;
}
/*
tell the caller we have EOF
*/
static void packet_eof(struct packet_context *pc)
{
packet_error(pc, NT_STATUS_END_OF_FILE);
}
/*
used to put packets on event boundaries
*/
static void packet_next_event(struct event_context *ev, struct timed_event *te,
struct timeval t, void *private)
{
struct packet_context *pc = talloc_get_type(private, struct packet_context);
if (pc->num_read != 0 && pc->packet_size != 0 &&
pc->packet_size <= pc->num_read) {
packet_recv(pc);
}
}
/*
call this when the socket becomes readable to kick off the whole
stream parsing process
*/
void packet_recv(struct packet_context *pc)
{
size_t npending;
NTSTATUS status;
size_t nread = 0;
DATA_BLOB blob;
if (pc->processing) {
return;
}
if (pc->recv_disable) {
EVENT_FD_NOT_READABLE(pc->fde);
return;
}
if (pc->packet_size != 0 && pc->num_read >= pc->packet_size) {
goto next_partial;
}
if (pc->packet_size != 0) {
/* we've already worked out how long this next packet is, so skip the
socket_pending() call */
npending = pc->packet_size - pc->num_read;
} else if (pc->initial_read != 0) {
npending = pc->initial_read - pc->num_read;
} else {
if (pc->tls) {
status = tls_socket_pending(pc->tls, &npending);
} else if (pc->sock) {
status = socket_pending(pc->sock, &npending);
} else {
status = NT_STATUS_CONNECTION_DISCONNECTED;
}
if (!NT_STATUS_IS_OK(status)) {
packet_error(pc, status);
return;
}
}
if (npending == 0) {
packet_eof(pc);
return;
}
/* possibly expand the partial packet buffer */
if (npending + pc->num_read > pc->partial.length) {
status = data_blob_realloc(pc, &pc->partial, npending+pc->num_read);
if (!NT_STATUS_IS_OK(status)) {
packet_error(pc, status);
return;
}
}
if (pc->tls) {
status = tls_socket_recv(pc->tls, pc->partial.data + pc->num_read,
npending, &nread);
} else {
status = socket_recv(pc->sock, pc->partial.data + pc->num_read,
npending, &nread, 0);
}
if (NT_STATUS_IS_ERR(status)) {
packet_error(pc, status);
return;
}
if (!NT_STATUS_IS_OK(status)) {
return;
}
if (nread == 0) {
packet_eof(pc);
return;
}
pc->num_read += nread;
next_partial:
if (pc->partial.length != pc->num_read) {
status = data_blob_realloc(pc, &pc->partial, pc->num_read);
if (!NT_STATUS_IS_OK(status)) {
packet_error(pc, status);
return;
}
}
/* see if its a full request */
blob = pc->partial;
blob.length = pc->num_read;
status = pc->full_request(pc->private, blob, &pc->packet_size);
if (NT_STATUS_IS_ERR(status)) {
packet_error(pc, status);
return;
}
if (!NT_STATUS_IS_OK(status)) {
return;
}
if (pc->packet_size > pc->num_read) {
/* the caller made an error */
DEBUG(0,("Invalid packet_size %u greater than num_read %u\n",
pc->packet_size, pc->num_read));
packet_error(pc, NT_STATUS_INVALID_PARAMETER);
return;
}
/* it is a full request - give it to the caller */
blob = pc->partial;
blob.length = pc->num_read;
if (pc->packet_size < pc->num_read) {
pc->partial = data_blob_talloc(pc, blob.data + pc->packet_size,
pc->num_read - pc->packet_size);
if (pc->partial.data == NULL) {
packet_error(pc, NT_STATUS_NO_MEMORY);
return;
}
data_blob_realloc(pc, &blob, pc->packet_size);
} else {
pc->partial = data_blob(NULL, 0);
}
pc->num_read -= pc->packet_size;
pc->packet_size = 0;
if (pc->serialise) {
EVENT_FD_NOT_READABLE(pc->fde);
pc->processing = True;
}
status = pc->callback(pc->private, blob);
if (pc->serialise) {
EVENT_FD_READABLE(pc->fde);
pc->processing = False;
}
if (!NT_STATUS_IS_OK(status)) {
packet_error(pc, status);
return;
}
if (pc->partial.length == 0) {
return;
}
/* we got multiple packets in one tcp read */
if (pc->ev == NULL) {
goto next_partial;
}
blob = pc->partial;
blob.length = pc->num_read;
status = pc->full_request(pc->private, blob, &pc->packet_size);
if (NT_STATUS_IS_ERR(status)) {
packet_error(pc, status);
return;
}
if (!NT_STATUS_IS_OK(status)) {
return;
}
event_add_timed(pc->ev, pc, timeval_zero(), packet_next_event, pc);
}
/*
temporarily disable receiving
*/
void packet_recv_disable(struct packet_context *pc)
{
EVENT_FD_NOT_READABLE(pc->fde);
pc->recv_disable = True;
}
/*
re-enable receiving
*/
void packet_recv_enable(struct packet_context *pc)
{
EVENT_FD_READABLE(pc->fde);
pc->recv_disable = False;
if (pc->num_read != 0 && pc->packet_size >= pc->num_read) {
event_add_timed(pc->ev, pc, timeval_zero(), packet_next_event, pc);
}
}
/*
trigger a run of the send queue
*/
void packet_queue_run(struct packet_context *pc)
{
while (pc->send_queue) {
struct send_element *el = pc->send_queue;
NTSTATUS status;
size_t nwritten;
DATA_BLOB blob = data_blob_const(el->blob.data + el->nsent,
el->blob.length - el->nsent);
if (pc->tls) {
status = tls_socket_send(pc->tls, &blob, &nwritten);
} else {
status = socket_send(pc->sock, &blob, &nwritten, 0);
}
if (NT_STATUS_IS_ERR(status)) {
packet_error(pc, NT_STATUS_NET_WRITE_FAULT);
return;
}
if (!NT_STATUS_IS_OK(status)) {
return;
}
el->nsent += nwritten;
if (el->nsent == el->blob.length) {
DLIST_REMOVE(pc->send_queue, el);
talloc_free(el);
}
}
/* we're out of requests to send, so don't wait for write
events any more */
EVENT_FD_NOT_WRITEABLE(pc->fde);
}
/*
put a packet in the send queue
*/
NTSTATUS packet_send(struct packet_context *pc, DATA_BLOB blob)
{
struct send_element *el;
el = talloc(pc, struct send_element);
NT_STATUS_HAVE_NO_MEMORY(el);
DLIST_ADD_END(pc->send_queue, el, struct send_element *);
el->blob = blob;
el->nsent = 0;
/* if we aren't going to free the packet then we must reference it
to ensure it doesn't disappear before going out */
if (pc->nofree) {
talloc_reference(el, blob.data);
} else {
talloc_steal(el, blob.data);
}
EVENT_FD_WRITEABLE(pc->fde);
return NT_STATUS_OK;
}
/*
a full request checker for NBT formatted packets (first 3 bytes are length)
*/
NTSTATUS packet_full_request_nbt(void *private, DATA_BLOB blob, size_t *size)
{
if (blob.length < 4) {
return STATUS_MORE_ENTRIES;
}
*size = 4 + smb_len(blob.data);
if (*size > blob.length) {
return STATUS_MORE_ENTRIES;
}
return NT_STATUS_OK;
}
/*
work out if a packet is complete for protocols that use a 32 bit network byte
order length
*/
NTSTATUS packet_full_request_u32(void *private, DATA_BLOB blob, size_t *size)
{
if (blob.length < 4) {
return STATUS_MORE_ENTRIES;
}
*size = 4 + RIVAL(blob.data, 0);
if (*size > blob.length) {
return STATUS_MORE_ENTRIES;
}
return NT_STATUS_OK;
}