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|
/*
Unix SMB/CIFS implementation.
Samba internal messaging functions
Copyright (C) Andrew Tridgell 2004
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 "lib/events/events.h"
#include "system/dir.h"
#include "system/filesys.h"
#include "system/time.h"
#include "messages.h"
#include "dlinklist.h"
#include "lib/socket/socket.h"
#include "librpc/gen_ndr/ndr_irpc.h"
#include "lib/messaging/irpc.h"
/* change the message version with any incompatible changes in the protocol */
#define MESSAGING_VERSION 1
struct messaging_context {
uint32_t server_id;
struct socket_context *sock;
const char *base_path;
const char *path;
struct dispatch_fn *dispatch;
struct messaging_rec *pending;
struct irpc_list *irpc;
struct idr_context *idr;
struct {
struct event_context *ev;
struct fd_event *fde;
} event;
};
/* we have a linked list of dispatch handlers that this messaging
server can deal with */
struct dispatch_fn {
struct dispatch_fn *next, *prev;
uint32_t msg_type;
void *private;
void (*fn)(struct messaging_context *msg, void *private,
uint32_t msg_type, uint32_t server_id, DATA_BLOB *data);
};
/* an individual message */
struct messaging_rec {
struct messaging_rec *next, *prev;
struct messaging_context *msg;
const char *path;
struct messaging_header {
uint32_t version;
uint32_t msg_type;
uint32_t from;
uint32_t to;
uint32_t length;
} *header;
DATA_BLOB packet;
};
static void irpc_handler(struct messaging_context *, void *,
uint32_t, uint32_t, DATA_BLOB *);
/*
A useful function for testing the message system.
*/
static void ping_message(struct messaging_context *msg, void *private,
uint32_t msg_type, uint32_t src, DATA_BLOB *data)
{
DEBUG(1,("INFO: Received PING message from server %u [%.*s]\n",
(uint_t)src, data->length, data->data?(const char *)data->data:""));
messaging_send(msg, src, MSG_PONG, data);
}
/*
return the path to a messaging socket
*/
static char *messaging_path(struct messaging_context *msg, uint32_t server_id)
{
return talloc_asprintf(msg, "%s/msg.%u", msg->base_path, (unsigned)server_id);
}
/*
dispatch a fully received message
*/
static void messaging_dispatch(struct messaging_context *msg, struct messaging_rec *rec)
{
struct dispatch_fn *d, *next;
for (d=msg->dispatch;d;d=next) {
next = d->next;
if (d->msg_type == rec->header->msg_type) {
DATA_BLOB data;
data.data = rec->packet.data + sizeof(*rec->header);
data.length = rec->header->length;
d->fn(msg, d->private, d->msg_type, rec->header->from, &data);
}
}
rec->header->length = 0;
}
/*
try to send the message
*/
static NTSTATUS try_send(struct messaging_rec *rec)
{
struct messaging_context *msg = rec->msg;
size_t nsent;
void *priv;
NTSTATUS status;
/* we send with privileges so messages work from any context */
priv = root_privileges();
status = socket_sendto(msg->sock, &rec->packet, &nsent, 0, rec->path, 0);
talloc_free(priv);
return status;
}
/*
handle a socket write event
*/
static void messaging_send_handler(struct messaging_context *msg)
{
while (msg->pending) {
struct messaging_rec *rec = msg->pending;
NTSTATUS status;
status = try_send(rec);
if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
break;
}
if (!NT_STATUS_IS_OK(status)) {
DEBUG(1,("messaging: Lost message from %u to %u of type %u - %s\n",
rec->header->from, rec->header->to, rec->header->msg_type,
nt_errstr(status)));
}
DLIST_REMOVE(msg->pending, rec);
talloc_free(rec);
}
if (msg->pending == NULL) {
EVENT_FD_NOT_WRITEABLE(msg->event.fde);
}
}
/*
handle a new incoming packet
*/
static void messaging_recv_handler(struct messaging_context *msg)
{
struct messaging_rec *rec;
NTSTATUS status;
DATA_BLOB packet;
size_t msize;
/* see how many bytes are in the next packet */
status = socket_pending(msg->sock, &msize);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0,("socket_pending failed in messaging - %s\n",
nt_errstr(status)));
return;
}
packet = data_blob_talloc(msg, NULL, msize);
if (packet.data == NULL) {
/* assume this is temporary and retry */
return;
}
status = socket_recv(msg->sock, packet.data, msize, &msize, 0);
if (!NT_STATUS_IS_OK(status)) {
data_blob_free(&packet);
return;
}
if (msize < sizeof(*rec->header)) {
DEBUG(0,("messaging: bad message of size %d\n", msize));
data_blob_free(&packet);
return;
}
rec = talloc(msg, struct messaging_rec);
if (rec == NULL) {
smb_panic("Unable to allocate messaging_rec");
}
talloc_steal(rec, packet.data);
rec->msg = msg;
rec->path = msg->path;
rec->header = (struct messaging_header *)packet.data;
rec->packet = packet;
if (msize != sizeof(*rec->header) + rec->header->length) {
DEBUG(0,("messaging: bad message header size %d should be %d\n",
rec->header->length, msize - sizeof(*rec->header)));
talloc_free(rec);
return;
}
messaging_dispatch(msg, rec);
talloc_free(rec);
}
/*
handle a socket event
*/
static void messaging_handler(struct event_context *ev, struct fd_event *fde,
uint16_t flags, void *private)
{
struct messaging_context *msg = talloc_get_type(private,
struct messaging_context);
if (flags & EVENT_FD_WRITE) {
messaging_send_handler(msg);
}
if (flags & EVENT_FD_READ) {
messaging_recv_handler(msg);
}
}
/*
Register a dispatch function for a particular message type.
*/
void messaging_register(struct messaging_context *msg, void *private,
uint32_t msg_type,
void (*fn)(struct messaging_context *, void *, uint32_t, uint32_t, DATA_BLOB *))
{
struct dispatch_fn *d;
d = talloc(msg, struct dispatch_fn);
d->msg_type = msg_type;
d->private = private;
d->fn = fn;
DLIST_ADD(msg->dispatch, d);
}
/*
De-register the function for a particular message type.
*/
void messaging_deregister(struct messaging_context *msg, uint32_t msg_type, void *private)
{
struct dispatch_fn *d, *next;
for (d = msg->dispatch; d; d = next) {
next = d->next;
if (d->msg_type == msg_type &&
d->private == private) {
DLIST_REMOVE(msg->dispatch, d);
talloc_free(d);
}
}
}
/*
Send a message to a particular server
*/
NTSTATUS messaging_send(struct messaging_context *msg, uint32_t server,
uint32_t msg_type, DATA_BLOB *data)
{
struct messaging_rec *rec;
NTSTATUS status;
size_t dlength = data?data->length:0;
rec = talloc(msg, struct messaging_rec);
if (rec == NULL) {
return NT_STATUS_NO_MEMORY;
}
rec->packet = data_blob_talloc(rec, NULL, sizeof(*rec->header) + dlength);
if (rec->packet.data == NULL) {
talloc_free(rec);
return NT_STATUS_NO_MEMORY;
}
rec->msg = msg;
rec->header = (struct messaging_header *)rec->packet.data;
rec->header->version = MESSAGING_VERSION;
rec->header->msg_type = msg_type;
rec->header->from = msg->server_id;
rec->header->to = server;
rec->header->length = dlength;
if (dlength != 0) {
memcpy(rec->packet.data + sizeof(*rec->header),
data->data, dlength);
}
rec->path = messaging_path(msg, server);
talloc_steal(rec, rec->path);
if (msg->pending != NULL) {
status = STATUS_MORE_ENTRIES;
} else {
status = try_send(rec);
}
if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
if (msg->pending == NULL) {
EVENT_FD_WRITEABLE(msg->event.fde);
}
DLIST_ADD_END(msg->pending, rec, struct messaging_rec *);
return NT_STATUS_OK;
}
talloc_free(rec);
return status;
}
/*
Send a message to a particular server, with the message containing a single pointer
*/
NTSTATUS messaging_send_ptr(struct messaging_context *msg, uint32_t server,
uint32_t msg_type, void *ptr)
{
DATA_BLOB blob;
blob.data = (void *)&ptr;
blob.length = sizeof(void *);
return messaging_send(msg, server, msg_type, &blob);
}
/*
destroy the messaging context
*/
static int messaging_destructor(void *ptr)
{
struct messaging_context *msg = ptr;
unlink(msg->path);
return 0;
}
/*
create the listening socket and setup the dispatcher
*/
struct messaging_context *messaging_init(TALLOC_CTX *mem_ctx, uint32_t server_id,
struct event_context *ev)
{
struct messaging_context *msg;
NTSTATUS status;
char *path;
msg = talloc(mem_ctx, struct messaging_context);
if (msg == NULL) {
return NULL;
}
/* create the messaging directory if needed */
path = smbd_tmp_path(msg, "messaging");
mkdir(path, 0700);
talloc_free(path);
msg->base_path = smbd_tmp_path(msg, "messaging");
msg->path = messaging_path(msg, server_id);
msg->server_id = server_id;
msg->dispatch = NULL;
msg->pending = NULL;
msg->idr = idr_init(msg);
msg->irpc = NULL;
status = socket_create("unix", SOCKET_TYPE_DGRAM, &msg->sock, 0);
if (!NT_STATUS_IS_OK(status)) {
talloc_free(msg);
return NULL;
}
/* by stealing here we ensure that the socket is cleaned up (and even
deleted) on exit */
talloc_steal(msg, msg->sock);
status = socket_listen(msg->sock, msg->path, 0, 50, 0);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(0,("Unable to setup messaging listener for '%s':%s\n", msg->path, nt_errstr(status)));
talloc_free(msg);
return NULL;
}
/* it needs to be non blocking for sends */
set_blocking(socket_get_fd(msg->sock), False);
msg->event.ev = talloc_reference(msg, ev);
msg->event.fde = event_add_fd(ev, msg, socket_get_fd(msg->sock),
EVENT_FD_READ, messaging_handler, msg);
talloc_set_destructor(msg, messaging_destructor);
messaging_register(msg, NULL, MSG_PING, ping_message);
messaging_register(msg, NULL, MSG_IRPC, irpc_handler);
return msg;
}
/*
a list of registered irpc server functions
*/
struct irpc_list {
struct irpc_list *next, *prev;
struct GUID uuid;
const struct dcerpc_interface_table *table;
int callnum;
irpc_function_t fn;
void *private;
};
/*
register a irpc server function
*/
NTSTATUS irpc_register(struct messaging_context *msg_ctx,
const struct dcerpc_interface_table *table,
int callnum, irpc_function_t fn, void *private)
{
struct irpc_list *irpc;
/* override an existing handler, if any */
for (irpc=msg_ctx->irpc; irpc; irpc=irpc->next) {
if (irpc->table == table && irpc->callnum == callnum) {
break;
}
}
if (irpc == NULL) {
irpc = talloc(msg_ctx, struct irpc_list);
NT_STATUS_HAVE_NO_MEMORY(irpc);
DLIST_ADD(msg_ctx->irpc, irpc);
}
irpc->table = table;
irpc->callnum = callnum;
irpc->fn = fn;
irpc->private = private;
GUID_from_string(irpc->table->uuid, &irpc->uuid);
return NT_STATUS_OK;
}
/*
handle an incoming irpc reply message
*/
static void irpc_handler_reply(struct messaging_context *msg_ctx,
struct ndr_pull *ndr, struct irpc_header *header)
{
struct irpc_request *irpc;
irpc = idr_find(msg_ctx->idr, header->callid);
if (irpc == NULL) return;
/* parse the reply data */
irpc->status = irpc->table->calls[irpc->callnum].ndr_pull(ndr, NDR_OUT, irpc->r);
if (NT_STATUS_IS_OK(irpc->status)) {
irpc->status = header->status;
}
irpc->done = True;
if (irpc->async.fn) {
irpc->async.fn(irpc);
}
}
/*
handle an incoming irpc request message
*/
static void irpc_handler_request(struct messaging_context *msg_ctx,
struct ndr_pull *ndr, struct irpc_header *header,
uint32_t src)
{
struct irpc_list *i;
void *r;
NTSTATUS status;
struct irpc_message m;
struct ndr_push *push;
DATA_BLOB packet;
for (i=msg_ctx->irpc; i; i=i->next) {
if (GUID_equal(&i->uuid, &header->uuid) &&
i->table->if_version == header->if_version &&
i->callnum == header->callnum) {
break;
}
}
if (i == NULL) {
/* no registered handler for this message */
return;
}
/* allocate space for the structure */
r = talloc_zero_size(ndr, i->table->calls[header->callnum].struct_size);
if (r == NULL) goto failed;
/* parse the request data */
status = i->table->calls[i->callnum].ndr_pull(ndr, NDR_IN, r);
if (!NT_STATUS_IS_OK(status)) goto failed;
/* make the call */
m.from = src;
m.private = i->private;
header->status = i->fn(&m, r);
/* setup the reply */
push = ndr_push_init_ctx(ndr);
if (push == NULL) goto failed;
header->flags |= IRPC_FLAG_REPLY;
/* construct the packet */
status = ndr_push_irpc_header(push, NDR_SCALARS|NDR_BUFFERS, header);
if (!NT_STATUS_IS_OK(status)) goto failed;
status = i->table->calls[i->callnum].ndr_push(push, NDR_OUT, r);
if (!NT_STATUS_IS_OK(status)) goto failed;
/* send the reply message */
packet = ndr_push_blob(push);
status = messaging_send(msg_ctx, src, MSG_IRPC, &packet);
if (!NT_STATUS_IS_OK(status)) goto failed;
failed:
/* nothing to clean up */
return;
}
/*
handle an incoming irpc message
*/
static void irpc_handler(struct messaging_context *msg_ctx, void *private,
uint32_t msg_type, uint32_t src, DATA_BLOB *packet)
{
struct irpc_header header;
struct ndr_pull *ndr;
NTSTATUS status;
ndr = ndr_pull_init_blob(packet, msg_ctx);
if (ndr == NULL) goto failed;
status = ndr_pull_irpc_header(ndr, NDR_BUFFERS|NDR_SCALARS, &header);
if (!NT_STATUS_IS_OK(status)) goto failed;
if (header.flags & IRPC_FLAG_REPLY) {
irpc_handler_reply(msg_ctx, ndr, &header);
} else {
irpc_handler_request(msg_ctx, ndr, &header, src);
}
failed:
talloc_free(ndr);
}
/*
destroy a irpc request
*/
static int irpc_destructor(void *ptr)
{
struct irpc_request *irpc = talloc_get_type(ptr, struct irpc_request);
idr_remove(irpc->msg_ctx->idr, irpc->callid);
return 0;
}
/*
timeout a irpc request
*/
static void irpc_timeout(struct event_context *ev, struct timed_event *te,
struct timeval t, void *private)
{
struct irpc_request *irpc = talloc_get_type(private, struct irpc_request);
irpc->status = NT_STATUS_IO_TIMEOUT;
irpc->done = True;
if (irpc->async.fn) {
irpc->async.fn(irpc);
}
}
/*
make a irpc call - async send
*/
struct irpc_request *irpc_call_send(struct messaging_context *msg_ctx,
uint32_t server_id,
const struct dcerpc_interface_table *table,
int callnum, void *r)
{
struct irpc_header header;
struct ndr_push *ndr;
NTSTATUS status;
DATA_BLOB packet;
struct irpc_request *irpc;
irpc = talloc(msg_ctx, struct irpc_request);
if (irpc == NULL) goto failed;
irpc->msg_ctx = msg_ctx;
irpc->table = table;
irpc->callnum = callnum;
irpc->callid = idr_get_new(msg_ctx->idr, irpc, UINT16_MAX);
if (irpc->callid == -1) goto failed;
irpc->r = r;
irpc->done = False;
irpc->async.fn = NULL;
talloc_set_destructor(irpc, irpc_destructor);
/* setup the header */
status = GUID_from_string(table->uuid, &header.uuid);
if (!NT_STATUS_IS_OK(status)) goto failed;
header.if_version = table->if_version;
header.callid = irpc->callid;
header.callnum = callnum;
header.flags = 0;
header.status = NT_STATUS_OK;
/* construct the irpc packet */
ndr = ndr_push_init_ctx(irpc);
if (ndr == NULL) goto failed;
status = ndr_push_irpc_header(ndr, NDR_SCALARS|NDR_BUFFERS, &header);
if (!NT_STATUS_IS_OK(status)) goto failed;
status = table->calls[callnum].ndr_push(ndr, NDR_IN, r);
if (!NT_STATUS_IS_OK(status)) goto failed;
/* and send it */
packet = ndr_push_blob(ndr);
status = messaging_send(msg_ctx, server_id, MSG_IRPC, &packet);
if (!NT_STATUS_IS_OK(status)) goto failed;
event_add_timed(msg_ctx->event.ev, irpc,
timeval_current_ofs(IRPC_CALL_TIMEOUT, 0),
irpc_timeout, irpc);
talloc_free(ndr);
return irpc;
failed:
talloc_free(irpc);
return NULL;
}
/*
wait for a irpc reply
*/
NTSTATUS irpc_call_recv(struct irpc_request *irpc)
{
NTSTATUS status;
NT_STATUS_HAVE_NO_MEMORY(irpc);
while (!irpc->done) {
if (event_loop_once(irpc->msg_ctx->event.ev) != 0) {
return NT_STATUS_CONNECTION_DISCONNECTED;
}
}
status = irpc->status;
talloc_free(irpc);
return status;
}
/*
perform a synchronous irpc request
*/
NTSTATUS irpc_call(struct messaging_context *msg_ctx,
uint32_t server_id,
const struct dcerpc_interface_table *table,
int callnum, void *r)
{
struct irpc_request *irpc = irpc_call_send(msg_ctx, server_id,
table, callnum, r);
return irpc_call_recv(irpc);
}
/*
add a string name that this irpc server can be called on
*/
NTSTATUS irpc_add_name(struct messaging_context *msg_ctx, const char *name)
{
return NT_STATUS_OK;
}
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