source: trunk/server/source4/libcli/smb2/transport.c

/* 
   Unix SMB/CIFS implementation.

   SMB2 client transport context management functions

   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "libcli/raw/libcliraw.h"
#include "libcli/raw/raw_proto.h"
#include "libcli/smb2/smb2.h"
#include "libcli/smb2/smb2_calls.h"
#include "lib/socket/socket.h"
#include "lib/events/events.h"
#include "lib/stream/packet.h"
#include "../lib/util/dlinklist.h"


/*
  an event has happened on the socket
*/
static void smb2_transport_event_handler(struct tevent_context *ev, 
                                         struct tevent_fd *fde, 
                                         uint16_t flags, void *private_data)
{
        struct smb2_transport *transport = talloc_get_type(private_data,
                                                           struct smb2_transport);
        if (flags & EVENT_FD_READ) {
                packet_recv(transport->packet);
                return;
        }
        if (flags & EVENT_FD_WRITE) {
                packet_queue_run(transport->packet);
        }
}

/*
  destroy a transport
 */
static int transport_destructor(struct smb2_transport *transport)
{
        smb2_transport_dead(transport, NT_STATUS_LOCAL_DISCONNECT);
        return 0;
}


/*
  handle receive errors
*/
static void smb2_transport_error(void *private_data, NTSTATUS status)
{
        struct smb2_transport *transport = talloc_get_type(private_data,
                                                           struct smb2_transport);
        smb2_transport_dead(transport, status);
}

static NTSTATUS smb2_transport_finish_recv(void *private_data, DATA_BLOB blob);

/*
  create a transport structure based on an established socket
*/
struct smb2_transport *smb2_transport_init(struct smbcli_socket *sock,
                                           TALLOC_CTX *parent_ctx,
                                           struct smbcli_options *options)
{
        struct smb2_transport *transport;

        transport = talloc_zero(parent_ctx, struct smb2_transport);
        if (!transport) return NULL;

        transport->socket = talloc_steal(transport, sock);
        transport->options = *options;
        transport->credits.charge = 0;
        transport->credits.ask_num = 1;

        /* setup the stream -> packet parser */
        transport->packet = packet_init(transport);
        if (transport->packet == NULL) {
                talloc_free(transport);
                return NULL;
        }
        packet_set_private(transport->packet, transport);
        packet_set_socket(transport->packet, transport->socket->sock);
        packet_set_callback(transport->packet, smb2_transport_finish_recv);
        packet_set_full_request(transport->packet, packet_full_request_nbt);
        packet_set_error_handler(transport->packet, smb2_transport_error);
        packet_set_event_context(transport->packet, transport->socket->event.ctx);
        packet_set_nofree(transport->packet);

        /* take over event handling from the socket layer - it only
           handles events up until we are connected */
        talloc_free(transport->socket->event.fde);
        transport->socket->event.fde = event_add_fd(transport->socket->event.ctx,
                                                    transport->socket,
                                                    socket_get_fd(transport->socket->sock),
                                                    EVENT_FD_READ,
                                                    smb2_transport_event_handler,
                                                    transport);

        packet_set_fde(transport->packet, transport->socket->event.fde);
        packet_set_serialise(transport->packet);

        talloc_set_destructor(transport, transport_destructor);

        return transport;
}

/*
  mark the transport as dead
*/
void smb2_transport_dead(struct smb2_transport *transport, NTSTATUS status)
{
        smbcli_sock_dead(transport->socket);

        if (NT_STATUS_EQUAL(NT_STATUS_UNSUCCESSFUL, status)) {
                status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
        }

        /* kill all pending receives */
        while (transport->pending_recv) {
                struct smb2_request *req = transport->pending_recv;
                req->state = SMB2_REQUEST_ERROR;
                req->status = status;
                DLIST_REMOVE(transport->pending_recv, req);
                if (req->async.fn) {
                        req->async.fn(req);
                }
        }
}

static NTSTATUS smb2_handle_oplock_break(struct smb2_transport *transport,
                                         const DATA_BLOB *blob)
{
        uint8_t *hdr;
        uint8_t *body;
        uint16_t len, bloblen;
        bool lease;

        hdr = blob->data+NBT_HDR_SIZE;
        body = hdr+SMB2_HDR_BODY;
        bloblen = blob->length - SMB2_HDR_BODY;

        if (bloblen < 2) {
                DEBUG(1,("Discarding smb2 oplock reply of size %u\n",
                        (unsigned)blob->length));
                return NT_STATUS_INVALID_NETWORK_RESPONSE;
        }

        len = CVAL(body, 0x00);
        if (len > bloblen) {
                DEBUG(1,("Discarding smb2 oplock reply,"
                        "packet claims %u byte body, only %u bytes seen\n",
                        len, bloblen));
                return NT_STATUS_INVALID_NETWORK_RESPONSE;
        }

        if (len == 24) {
                lease = false;
        } else if (len == 44) {
                lease = true;
        } else {
                DEBUG(1,("Discarding smb2 oplock reply of invalid size %u\n",
                        (unsigned)blob->length));
                return NT_STATUS_INVALID_NETWORK_RESPONSE;
        }

        if (!lease && transport->oplock.handler) {
                struct smb2_handle h;
                uint8_t level;

                level = CVAL(body, 0x02);
                smb2_pull_handle(body+0x08, &h);

                transport->oplock.handler(transport, &h, level,
                                          transport->oplock.private_data);
        } else if (lease && transport->lease.handler) {
                struct smb2_lease_break lb;

                ZERO_STRUCT(lb);
                lb.break_flags =                SVAL(body, 0x4);
                memcpy(&lb.current_lease.lease_key, body+0x8,
                    sizeof(struct smb2_lease_key));
                lb.current_lease.lease_state =  SVAL(body, 0x18);
                lb.new_lease_state =            SVAL(body, 0x1C);
                lb.break_reason =               SVAL(body, 0x20);
                lb.access_mask_hint =           SVAL(body, 0x24);
                lb.share_mask_hint =            SVAL(body, 0x28);

                transport->lease.handler(transport, &lb,
                    transport->lease.private_data);
        } else {
                DEBUG(5,("Got SMB2 %s break with no handler\n",
                        lease ? "lease" : "oplock"));
        }

        return NT_STATUS_OK;
}

struct smb2_transport_compount_response_state {
        struct smb2_transport *transport;
        DATA_BLOB blob;
};

static void smb2_transport_compound_response_handler(struct tevent_context *ctx,
                                                     struct tevent_immediate *im,
                                                     void *private_data)
{
        struct smb2_transport_compount_response_state *state =
                talloc_get_type_abort(private_data,
                struct smb2_transport_compount_response_state);
        struct smb2_transport *transport = state->transport;
        NTSTATUS status;

        status = smb2_transport_finish_recv(transport, state->blob);
        TALLOC_FREE(state);
        if (!NT_STATUS_IS_OK(status)) {
                smb2_transport_error(transport, status);
        }
}

/*
  we have a full request in our receive buffer - match it to a pending request
  and process
 */
static NTSTATUS smb2_transport_finish_recv(void *private_data, DATA_BLOB blob)
{
        struct smb2_transport *transport = talloc_get_type(private_data,
                                                             struct smb2_transport);
        uint8_t *buffer, *hdr;
        int len;
        struct smb2_request *req = NULL;
        uint64_t seqnum;
        uint32_t flags;
        uint16_t buffer_code;
        uint32_t dynamic_size;
        uint32_t i;
        uint16_t opcode;
        NTSTATUS status;
        uint32_t next_ofs;

        buffer = blob.data;
        len = blob.length;

        hdr = buffer+NBT_HDR_SIZE;

        if (len < SMB2_MIN_SIZE) {
                DEBUG(1,("Discarding smb2 reply of size %d\n", len));
                goto error;
        }

        flags   = IVAL(hdr, SMB2_HDR_FLAGS);
        seqnum  = BVAL(hdr, SMB2_HDR_MESSAGE_ID);
        opcode  = SVAL(hdr, SMB2_HDR_OPCODE);

        /* see MS-SMB2 3.2.5.19 */
        if (seqnum == UINT64_MAX) {
                if (opcode != SMB2_OP_BREAK) {
                        DEBUG(1,("Discarding packet with invalid seqnum, "
                                "opcode %u\n", opcode));
                        return NT_STATUS_INVALID_NETWORK_RESPONSE;
                }

                return smb2_handle_oplock_break(transport, &blob);
        }

        /* match the incoming request against the list of pending requests */
        for (req=transport->pending_recv; req; req=req->next) {
                if (req->seqnum == seqnum) break;
        }

        if (!req) {
                DEBUG(1,("Discarding unmatched reply with seqnum 0x%llx op %d\n", 
                         (long long)seqnum, SVAL(hdr, SMB2_HDR_OPCODE)));
                goto error;
        }

        /* fill in the 'in' portion of the matching request */
        req->in.buffer = buffer;
        talloc_steal(req, buffer);
        req->in.size = len;
        req->in.allocated = req->in.size;

        req->in.hdr       = hdr;
        req->in.body      = hdr+SMB2_HDR_BODY;
        req->in.body_size = req->in.size - (SMB2_HDR_BODY+NBT_HDR_SIZE);
        req->status       = NT_STATUS(IVAL(hdr, SMB2_HDR_STATUS));

        if ((flags & SMB2_HDR_FLAG_ASYNC) &&
            NT_STATUS_EQUAL(req->status, STATUS_PENDING)) {
                req->cancel.can_cancel = true;
                req->cancel.async_id = BVAL(hdr, SMB2_HDR_ASYNC_ID);
                for (i=0; i< req->cancel.do_cancel; i++) {
                        smb2_cancel(req);
                }
                talloc_free(buffer);
                return NT_STATUS_OK;
        }

        next_ofs = IVAL(req->in.hdr, SMB2_HDR_NEXT_COMMAND);
        if (next_ofs > 0) {
                if (smb2_oob(&req->in, req->in.hdr + next_ofs, SMB2_HDR_BODY + 2)) {
                        DEBUG(1,("SMB2 request invalid next offset 0x%x\n",
                                 next_ofs));
                        goto error;
                }

                req->in.size = NBT_HDR_SIZE + next_ofs;
                req->in.body_size = req->in.size - (SMB2_HDR_BODY+NBT_HDR_SIZE);
        }

        if (req->session && req->session->signing_active) {
                status = smb2_check_signature(&req->in, 
                                              req->session->session_key);
                if (!NT_STATUS_IS_OK(status)) {
                        /* the spec says to ignore packets with a bad signature */
                        talloc_free(buffer);
                        return status;
                }
        }

        buffer_code = SVAL(req->in.body, 0);
        req->in.body_fixed = (buffer_code & ~1);
        req->in.dynamic = NULL;
        dynamic_size = req->in.body_size - req->in.body_fixed;
        if (dynamic_size != 0 && (buffer_code & 1)) {
                req->in.dynamic = req->in.body + req->in.body_fixed;
                if (smb2_oob(&req->in, req->in.dynamic, dynamic_size)) {
                        DEBUG(1,("SMB2 request invalid dynamic size 0x%x\n", 
                                 dynamic_size));
                        goto error;
                }
        }

        smb2_setup_bufinfo(req);

        DEBUG(2, ("SMB2 RECV seqnum=0x%llx\n", (long long)req->seqnum));
        dump_data(5, req->in.body, req->in.body_size);

        if (next_ofs > 0) {
                struct tevent_immediate *im;
                struct smb2_transport_compount_response_state *state;

                state = talloc(transport,
                               struct smb2_transport_compount_response_state);
                if (!state) {
                        goto error;
                }
                state->transport = transport;

                state->blob = data_blob_talloc(state, NULL,
                                               blob.length - next_ofs);
                if (!state->blob.data) {
                        goto error;
                }
                im = tevent_create_immediate(state);
                if (!im) {
                        TALLOC_FREE(state);
                        goto error;
                }
                _smb2_setlen(state->blob.data, state->blob.length - NBT_HDR_SIZE);
                memcpy(state->blob.data + NBT_HDR_SIZE,
                       req->in.hdr + next_ofs,
                       req->in.allocated - req->in.size);
                tevent_schedule_immediate(im, transport->socket->event.ctx,
                                          smb2_transport_compound_response_handler,
                                          state);
        }

        /* if this request has an async handler then call that to
           notify that the reply has been received. This might destroy
           the request so it must happen last */
        DLIST_REMOVE(transport->pending_recv, req);
        req->state = SMB2_REQUEST_DONE;
        if (req->async.fn) {
                req->async.fn(req);
        }
        return NT_STATUS_OK;

error:
        dump_data(5, buffer, len);
        if (req) {
                DLIST_REMOVE(transport->pending_recv, req);
                req->state = SMB2_REQUEST_ERROR;
                if (req->async.fn) {
                        req->async.fn(req);
                }
        } else {
                talloc_free(buffer);
        }
        return NT_STATUS_UNSUCCESSFUL;
}

/*
  handle timeouts of individual smb requests
*/
static void smb2_timeout_handler(struct tevent_context *ev, struct tevent_timer *te, 
                                 struct timeval t, void *private_data)
{
        struct smb2_request *req = talloc_get_type(private_data, struct smb2_request);

        if (req->state == SMB2_REQUEST_RECV) {
                DLIST_REMOVE(req->transport->pending_recv, req);
        }
        req->status = NT_STATUS_IO_TIMEOUT;
        req->state = SMB2_REQUEST_ERROR;
        if (req->async.fn) {
                req->async.fn(req);
        }
}


/*
  destroy a request
*/
static int smb2_request_destructor(struct smb2_request *req)
{
        if (req->state == SMB2_REQUEST_RECV) {
                DLIST_REMOVE(req->transport->pending_recv, req);
        }
        return 0;
}

static NTSTATUS smb2_transport_raw_send(struct smb2_transport *transport,
                                        struct smb2_request_buffer *buffer)
{
        DATA_BLOB blob;
        NTSTATUS status;

        /* check if the transport is dead */
        if (transport->socket->sock == NULL) {
                return NT_STATUS_NET_WRITE_FAULT;
        }

        _smb2_setlen(buffer->buffer, buffer->size - NBT_HDR_SIZE);
        blob = data_blob_const(buffer->buffer, buffer->size);
        status = packet_send(transport->packet, blob);
        if (!NT_STATUS_IS_OK(status)) {
                return status;
        }

        return NT_STATUS_OK;
}

/*
  put a request into the send queue
*/
void smb2_transport_send(struct smb2_request *req)
{
        NTSTATUS status;

        DEBUG(2, ("SMB2 send seqnum=0x%llx\n", (long long)req->seqnum));
        dump_data(5, req->out.body, req->out.body_size);

        if (req->transport->compound.missing > 0) {
                off_t next_ofs;
                size_t pad = 0;
                uint8_t *end;

                end = req->out.buffer + req->out.size;

                /*
                 * we need to set dynamic otherwise
                 * smb2_grow_buffer segfaults
                 */
                if (req->out.dynamic == NULL) {
                        req->out.dynamic = end;
                }

                next_ofs = end - req->out.hdr;
                if ((next_ofs % 8) > 0) {
                        pad = 8 - (next_ofs % 8);
                }
                next_ofs += pad;

                status = smb2_grow_buffer(&req->out, pad);
                if (!NT_STATUS_IS_OK(status)) {
                        req->state = SMB2_REQUEST_ERROR;
                        req->status = status;
                        return;
                }
                req->out.size += pad;

                SIVAL(req->out.hdr, SMB2_HDR_NEXT_COMMAND, next_ofs);
        }

        /* possibly sign the message */
        if (req->session && req->session->signing_active) {
                status = smb2_sign_message(&req->out, req->session->session_key);
                if (!NT_STATUS_IS_OK(status)) {
                        req->state = SMB2_REQUEST_ERROR;
                        req->status = status;
                        return;
                }
        }

        if (req->transport->compound.missing > 0) {
                req->transport->compound.buffer = req->out;
        } else {
                status = smb2_transport_raw_send(req->transport,
                                                 &req->out);
                if (!NT_STATUS_IS_OK(status)) {
                        req->state = SMB2_REQUEST_ERROR;
                        req->status = status;
                        return;
                }
        }
        ZERO_STRUCT(req->out);

        req->state = SMB2_REQUEST_RECV;
        DLIST_ADD(req->transport->pending_recv, req);

        /* add a timeout */
        if (req->transport->options.request_timeout) {
                event_add_timed(req->transport->socket->event.ctx, req, 
                                timeval_current_ofs(req->transport->options.request_timeout, 0), 
                                smb2_timeout_handler, req);
        }

        talloc_set_destructor(req, smb2_request_destructor);
}

NTSTATUS smb2_transport_compound_start(struct smb2_transport *transport,
                                       uint32_t num)
{
        ZERO_STRUCT(transport->compound);
        transport->compound.missing = num;
        return NT_STATUS_OK;
}

void smb2_transport_compound_set_related(struct smb2_transport *transport,
                                         bool related)
{
        transport->compound.related = related;
}

void smb2_transport_credits_ask_num(struct smb2_transport *transport,
                                    uint16_t ask_num)
{
        transport->credits.ask_num = ask_num;
}

void smb2_transport_credits_set_charge(struct smb2_transport *transport,
                                       uint16_t charge)
{
        transport->credits.charge = charge;
}

static void idle_handler(struct tevent_context *ev, 
                         struct tevent_timer *te, struct timeval t, void *private_data)
{
        struct smb2_transport *transport = talloc_get_type(private_data,
                                                           struct smb2_transport);
        struct timeval next = timeval_add(&t, 0, transport->idle.period);
        transport->socket->event.te = event_add_timed(transport->socket->event.ctx, 
                                                      transport,
                                                      next,
                                                      idle_handler, transport);
        transport->idle.func(transport, transport->idle.private_data);
}

/*
  setup the idle handler for a transport
  the period is in microseconds
*/
void smb2_transport_idle_handler(struct smb2_transport *transport, 
                                 void (*idle_func)(struct smb2_transport *, void *),
                                 uint64_t period,
                                 void *private_data)
{
        transport->idle.func = idle_func;
        transport->idle.private_data = private_data;
        transport->idle.period = period;

        if (transport->socket->event.te != NULL) {
                talloc_free(transport->socket->event.te);
        }

        transport->socket->event.te = event_add_timed(transport->socket->event.ctx, 
                                                      transport,
                                                      timeval_current_ofs(0, period),
                                                      idle_handler, transport);
}