mirror of
https://github.com/samba-team/samba.git
synced 2024-12-27 03:21:53 +03:00
b6a515aca4
problem, and the del *.* mangling problem. I promised jra that I would
write a longer description of these soon.
(This used to be commit b6827a03e7
)
782 lines
30 KiB
Plaintext
782 lines
30 KiB
Plaintext
|
|
|
|
THIS IS INCOMPLETE! I'M ONLY COMMITING IT IN ORDER TO SOLICIT COMMENTS
|
|
FROM A FEW PEOPLE. DON'T TAKE THIS AS THE FINAL VERSION YET.
|
|
|
|
|
|
Samba4 Programming Guide
|
|
------------------------
|
|
|
|
The internals of Samba4 are quite different from previous versions of
|
|
Samba, so even if you are an experienced Samba developer please take
|
|
the time to read through this document.
|
|
|
|
This document will explain both the broad structure of Samba4, and
|
|
some of the common coding elements such as memory management and
|
|
dealing with macros.
|
|
|
|
|
|
Coding Style
|
|
------------
|
|
|
|
In past versions of Samba we have basically let each programmer choose
|
|
their own programming style. Unfortunately the result has often been
|
|
that code that other members of the team find difficult to read. For
|
|
Samba version 4 I would like to standardise on a common coding style
|
|
to make the whole tree more readable. For those of you who are
|
|
horrified at the idea of having to learn a new style, I can assure you
|
|
that it isn't as painful as you might think. I was forced to adopt a
|
|
new style when I started working on the Linux kernel, and after some
|
|
initial pain found it quite easy.
|
|
|
|
That said, I don't want to invent a new style, instead I would like to
|
|
adopt the style used by the Linux kernel. It is a widely used style
|
|
with plenty of support tools available. See Documentation/CodingStyle
|
|
in the Linux source tree. This is the style that I have used to write
|
|
all of the core infrastructure for Samba4 and I think that we should
|
|
continue with that style.
|
|
|
|
I also think that we should most definately *not* adopt an automatic
|
|
reformatting system in cvs (or whatever other source code system we
|
|
end up using in the future). Such automatic formatters are, in my
|
|
experience, incredibly error prone and don't understand the necessary
|
|
exceptions. I don't mind if people use automated tools to reformat
|
|
their own code before they commit it, but please do not run such
|
|
automated tools on large slabs of existing code without being willing
|
|
to spend a *lot* of time hand checking the results.
|
|
|
|
Finally, I think that for code that is parsing or formatting protocol
|
|
packets the code layout should strongly reflect the packet
|
|
format. That means ordring the code so that it parses in the same
|
|
order as the packet is stored on the wire (where possible) and using
|
|
white space to align packet offsets so that a reader can immediately
|
|
map any line of the code to the corresponding place in the packet.
|
|
|
|
|
|
Static and Global Data
|
|
----------------------
|
|
|
|
The basic rule is "avoid static and global data like the plague". What
|
|
do I mean by static data? The way to tell if you have static data in a
|
|
file is to use the "size" utility in Linux. For example if we run:
|
|
|
|
size libcli/raw/*.o
|
|
|
|
in Samba4 then you get the following:
|
|
|
|
text data bss dec hex filename
|
|
2015 0 0 2015 7df libcli/raw/clikrb5.o
|
|
202 0 0 202 ca libcli/raw/clioplock.o
|
|
35 0 0 35 23 libcli/raw/clirewrite.o
|
|
3891 0 0 3891 f33 libcli/raw/clisession.o
|
|
869 0 0 869 365 libcli/raw/clisocket.o
|
|
4962 0 0 4962 1362 libcli/raw/clispnego.o
|
|
1223 0 0 1223 4c7 libcli/raw/clitransport.o
|
|
2294 0 0 2294 8f6 libcli/raw/clitree.o
|
|
1081 0 0 1081 439 libcli/raw/raweas.o
|
|
6765 0 0 6765 1a6d libcli/raw/rawfile.o
|
|
6824 0 0 6824 1aa8 libcli/raw/rawfileinfo.o
|
|
2944 0 0 2944 b80 libcli/raw/rawfsinfo.o
|
|
541 0 0 541 21d libcli/raw/rawioctl.o
|
|
1728 0 0 1728 6c0 libcli/raw/rawnegotiate.o
|
|
723 0 0 723 2d3 libcli/raw/rawnotify.o
|
|
3779 0 0 3779 ec3 libcli/raw/rawreadwrite.o
|
|
6597 0 0 6597 19c5 libcli/raw/rawrequest.o
|
|
5580 0 0 5580 15cc libcli/raw/rawsearch.o
|
|
3034 0 0 3034 bda libcli/raw/rawsetfileinfo.o
|
|
5187 0 0 5187 1443 libcli/raw/rawtrans.o
|
|
2033 0 0 2033 7f1 libcli/raw/smb_signing.o
|
|
|
|
notice that the "data" and "bss" columns are all zero? That is
|
|
good. If there are any non-zero values in data or bss then that
|
|
indicates static data and is bad (as a rule of thumb).
|
|
|
|
Lets compare that result to the equivalent in Samba3:
|
|
|
|
text data bss dec hex filename
|
|
3978 0 0 3978 f8a libsmb/asn1.o
|
|
18963 0 288 19251 4b33 libsmb/cliconnect.o
|
|
2815 0 1024 3839 eff libsmb/clidgram.o
|
|
4038 0 0 4038 fc6 libsmb/clientgen.o
|
|
3337 664 256 4257 10a1 libsmb/clierror.o
|
|
10043 0 0 10043 273b libsmb/clifile.o
|
|
332 0 0 332 14c libsmb/clifsinfo.o
|
|
166 0 0 166 a6 libsmb/clikrb5.o
|
|
5212 0 0 5212 145c libsmb/clilist.o
|
|
1367 0 0 1367 557 libsmb/climessage.o
|
|
259 0 0 259 103 libsmb/clioplock.o
|
|
1584 0 0 1584 630 libsmb/cliprint.o
|
|
7565 0 256 7821 1e8d libsmb/cliquota.o
|
|
7694 0 0 7694 1e0e libsmb/clirap.o
|
|
27440 0 0 27440 6b30 libsmb/clirap2.o
|
|
2905 0 0 2905 b59 libsmb/clireadwrite.o
|
|
1698 0 0 1698 6a2 libsmb/clisecdesc.o
|
|
5517 0 0 5517 158d libsmb/clispnego.o
|
|
485 0 0 485 1e5 libsmb/clistr.o
|
|
8449 0 0 8449 2101 libsmb/clitrans.o
|
|
2053 0 4 2057 809 libsmb/conncache.o
|
|
3041 0 256 3297 ce1 libsmb/credentials.o
|
|
1261 0 1024 2285 8ed libsmb/doserr.o
|
|
14560 0 0 14560 38e0 libsmb/errormap.o
|
|
3645 0 0 3645 e3d libsmb/namecache.o
|
|
16815 0 8 16823 41b7 libsmb/namequery.o
|
|
1626 0 0 1626 65a libsmb/namequery_dc.o
|
|
14301 0 1076 15377 3c11 libsmb/nmblib.o
|
|
24516 0 2048 26564 67c4 libsmb/nterr.o
|
|
8661 0 8 8669 21dd libsmb/ntlmssp.o
|
|
3188 0 0 3188 c74 libsmb/ntlmssp_parse.o
|
|
4945 0 0 4945 1351 libsmb/ntlmssp_sign.o
|
|
1303 0 0 1303 517 libsmb/passchange.o
|
|
1221 0 0 1221 4c5 libsmb/pwd_cache.o
|
|
2475 0 4 2479 9af libsmb/samlogon_cache.o
|
|
10768 32 0 10800 2a30 libsmb/smb_signing.o
|
|
4524 0 16 4540 11bc libsmb/smbdes.o
|
|
5708 0 0 5708 164c libsmb/smbencrypt.o
|
|
7049 0 3072 10121 2789 libsmb/smberr.o
|
|
2995 0 0 2995 bb3 libsmb/spnego.o
|
|
3186 0 0 3186 c72 libsmb/trustdom_cache.o
|
|
1742 0 0 1742 6ce libsmb/trusts_util.o
|
|
918 0 28 946 3b2 libsmb/unexpected.o
|
|
|
|
notice all of the non-zero data and bss elements? Every bit of that
|
|
data is a bug waiting to happen.
|
|
|
|
Static data is evil as it has the following consequences:
|
|
- it makes code much less likely to be thread-safe
|
|
- it makes code much less likely to be recursion-safe
|
|
- it leads to subtle side effects when the same code is called from
|
|
multiple places
|
|
|
|
Static data is particularly evil in library code (such as our internal
|
|
smb and rpc libraries). If you can get rid of all static data in
|
|
libraries then you can make some fairly strong guarantees about the
|
|
behaviour of functions in that library, which really helps.
|
|
|
|
Of course, it is possible to write code that uses static data and is
|
|
safe, it's just much harder to do that than just avoid static data in
|
|
the first place. We have been tripped up countless times by subtle
|
|
bugs in Samba due to the use of static data, so I think it is time to
|
|
start avoiding it in new code. Much of the core infrastructure of
|
|
Samba4 was specifically written to avoid static data, so I'm going to
|
|
be really annoyed if everyone starts adding lots of static data back
|
|
in.
|
|
|
|
So, how do we avoid static data? The basic method is to use context
|
|
pointers. When reading the Samba4 code you will notice that just about
|
|
every function takes a pointer to a context structure as its first
|
|
argument. Any data that the function needs that isn't an explicit
|
|
argument to the function can be found by traversing that context.
|
|
|
|
Note that this includes all of the little caches that we have lying
|
|
all over the code in Samba3. I'm referring to the ones that generally
|
|
have a "static int initialised" and then some static string or integer
|
|
that remembers the last return value of the function. Get rid of them!
|
|
If you are *REALLY* absolutely completely certain that your personal
|
|
favourite mini-cache is needed then you should do it properly by
|
|
putting it into the appropriate context rather than doing it the lazy
|
|
way by putting it inside the target function. I would suggest however
|
|
that the vast majority of those little caches are useless - don't
|
|
stick it in unless you have really firm benchmarking results that show
|
|
that it is needed and helps by a significant amount.
|
|
|
|
Note that Samba4 is not yet completely clean of static data like
|
|
this. I've gotten the smbd/ directory down to 24 bytes of static data,
|
|
and libcli/raw/ down to zero. I've also gotten the ntvfs layer and all
|
|
backends down to just 8 bytes in ntvfs_base.c. The rest still needs
|
|
some more work.
|
|
|
|
Also note that truly constant data is OK, and will not in fact show up
|
|
in the data and bss columns in "size" anyway (it will be included in
|
|
"text"). So you can have constant tables of protocol data.
|
|
|
|
|
|
How to use talloc
|
|
-----------------
|
|
|
|
Please see the separate document, talloc_guide.txt in this
|
|
directory. You _must_ read this if you want to program in Samba4.
|
|
|
|
Interface Structures
|
|
--------------------
|
|
|
|
One of the biggest changes in Samba4 is the universal use of interface
|
|
structures. Go take a look through include/smb_interfaces.h now to get
|
|
an idea of what I am talking about.
|
|
|
|
In Samba3 many of the core wire structures in the SMB protocol were
|
|
never explicitly defined in Samba. Instead, our parse and generation
|
|
functions just worked directly with wire buffers. The biggest problem
|
|
with this is that is tied our parse code with out "business logic"
|
|
much too closely, which meant the code got extremely confusing to
|
|
read.
|
|
|
|
In Samba4 we have explicitly defined interface structures for
|
|
everything in the protocol. When we receive a buffer we always parse
|
|
it completely into one of these structures, then we pass a pointer to
|
|
that structure to a backend handler. What we must *not* do is make any
|
|
decisions about the data inside the parse functions. That is critical
|
|
as different backends will need different portions of the data. This
|
|
leads to a golden rule for Samba4:
|
|
|
|
"don't design interfaces that lose information"
|
|
|
|
In Samba3 our backends often received "condensed" versions of the
|
|
information sent from clients, but this inevitably meant that some
|
|
backends could not get at the data they needed to do what they wanted,
|
|
so from now on we should expose the backends to all of the available
|
|
information and let them choose which bits they want.
|
|
|
|
Ok, so now some of you will be thinking "this sounds just like our
|
|
msrpc code from Samba3", and while to some extent this is true there
|
|
are extremely important differences in the approach that are worth
|
|
pointing out.
|
|
|
|
In the Samba3 msrpc code we used explicit parse strucrures for all
|
|
msrpc functions. The problem is that we didn't just put all of the
|
|
real variables in these structures, we also put in all the artifacts
|
|
as well. A good example is the security descriptor strucrure that
|
|
looks like this in Samba3:
|
|
|
|
typedef struct security_descriptor_info
|
|
{
|
|
uint16 revision;
|
|
uint16 type;
|
|
|
|
uint32 off_owner_sid;
|
|
uint32 off_grp_sid;
|
|
uint32 off_sacl;
|
|
uint32 off_dacl;
|
|
|
|
SEC_ACL *dacl;
|
|
SEC_ACL *sacl;
|
|
DOM_SID *owner_sid;
|
|
DOM_SID *grp_sid;
|
|
} SEC_DESC;
|
|
|
|
The problem with this structure is all the off_* variables. Those are
|
|
not part of the interface, and do not appear in any real descriptions
|
|
of Microsoft security descriptors. They are parsing artifacts
|
|
generated by the IDL compiler that Microsoft use. That doesn't mean
|
|
they aren't needed on the wire - indeed they are as they tell the
|
|
parser where to find the following four variables, but they should
|
|
*NOT* be in the interface structure.
|
|
|
|
In Samba3 there were unwritten rules about which variables in a
|
|
strucrure a high level caller has to fill in and which ones are filled
|
|
in by the marshalling code. In Samba4 those rules are gone, because
|
|
the redundent artifact variables are gone. The high level caller just
|
|
sets up the real variables and the marshalling code worries about
|
|
generating the right offsets.
|
|
|
|
The same rule applies to strings. In many places in the SMB and MSRPC
|
|
protocols complex strings are used on the wire, with complex rules
|
|
about padding, format, alighment, termination etc. None of that
|
|
information is useful to a high level calling routine or to a backend
|
|
- its all just so much wire fluff. So, in Samba4 these strings are
|
|
just "char *" and are always in our internal multi-byte format (which
|
|
is usually UTF8). It is up to the parse functions to worry about
|
|
translating the format and getting the padding right.
|
|
|
|
The one exception to this is the use of the WIRE_STRING type, but that
|
|
has a very good justification in terms of regression testing. Go and
|
|
read the comment in smb_interfaces.h about that now.
|
|
|
|
So, here is another rule to code by. When writing an interface
|
|
structure think carefully about what variables in the structure can be
|
|
left out as they are redundent. If some length is effectively defined
|
|
twice on the wire then only put it once in the packet. If a length can
|
|
be inferred from a null termination then do that and leave the length
|
|
out of the structure completely. Don't put redundent stuff in
|
|
structures!
|
|
|
|
|
|
Async Design
|
|
------------
|
|
|
|
Samba4 has an asynchronous design. That affects *lots* of the code,
|
|
and the implications of the asynchronous design needs to be considered
|
|
just about everywhere.
|
|
|
|
The first aspect of the async design to look at is the SMB client
|
|
library. Lets take a look at the following three functions in
|
|
libcli/raw/rawfile.c:
|
|
|
|
struct cli_request *smb_raw_seek_send(struct cli_tree *tree, struct smb_seek *parms);
|
|
NTSTATUS smb_raw_seek_recv(struct cli_request *req, struct smb_seek *parms);
|
|
NTSTATUS smb_raw_seek(struct cli_tree *tree, struct smb_seek *parms);
|
|
|
|
Go and read them now then come back.
|
|
|
|
Ok, first notice there there are 3 separate functions, whereas the
|
|
equivalent code in Samba3 had just one. Also note that the 3rd
|
|
function is extremely simple - its just a wrapper around calling the
|
|
first two in order.
|
|
|
|
The three separate functions are needed because we need to be able to
|
|
generate SMB calls asynchronously. The first call, which for smb calls
|
|
is always called smb_raw_XXXX_send(), constructs and sends a SMB
|
|
request and returns a "struct cli_request" which acts as a handle for
|
|
the request. The caller is then free to do lots of other calls if it
|
|
wants to, then when it is ready it can call the smb_raw_XXX_recv()
|
|
function to receive the reply.
|
|
|
|
If all you want is a synchronous call then call the 3rd interface, the
|
|
one called smb_raw_XXXX(). That just calls the first two in order, and
|
|
blocks waiting for the reply.
|
|
|
|
But what if you want to be called when the reply comes in? Yes, thats
|
|
possible. You can do things like this:
|
|
|
|
struct cli_request *req;
|
|
|
|
req = smb_raw_XXX_send(tree, params);
|
|
|
|
req->async.fn = my_callback;
|
|
req->async.private = my_private_data;
|
|
|
|
then in your callback function you can call the smb_raw_XXXX_recv()
|
|
function to receive the reply. Your callback will receive the "req"
|
|
pointer, which you can use to retrieve your private data from
|
|
req->async.private.
|
|
|
|
Then all you need to do is ensure that the main loop in the client
|
|
library gets called. You can either do that by polling the connection
|
|
using cli_transport_pending() and cli_request_receive_next() or you
|
|
can use transport->idle.func to setup an idle function handler to call
|
|
back to your main code. Either way, you can build a fully async
|
|
application.
|
|
|
|
In order to support all of this we have to make sure that when we
|
|
write a piece of library code (SMB, MSRPC etc) that we build the
|
|
separate _send() and _recv() functions. It really is worth the effort.
|
|
|
|
Now about async in smbd, a much more complex topic.
|
|
|
|
The SMB protocol is inherently async. Some functions (such as change
|
|
notify) often don't return for hours, while hundreds of other
|
|
functions pass through the socket. Take a look at the RAW-MUX test in
|
|
the Samba4 smbtorture to see some really extreme examples of the sort
|
|
of async operations that Windows supports. I particularly like the
|
|
open/open/close sequence where the 2nd open (which conflicts with the
|
|
first) succeeds because the subsequent close is answered out of order.
|
|
|
|
In Samba3 we handled this stuff very badly. We had awful "pending
|
|
request" queues that allocated full 128k packet buffers, and even with
|
|
all that crap we got the semantics wrong. In Samba4 I intend to make
|
|
sure we get this stuff right.
|
|
|
|
So, how do we do this? We now have an async interface between smbd and
|
|
the NTVFS backends. Whenever smbd calls into a backend the backend has
|
|
an option of answer the request in a synchronous fashion if it wants
|
|
to just like in Samba3, but it also has the option of answering the
|
|
request asynchronously. The only backend that currently does this is
|
|
the CIFS backend, but I hope the other backends will soon do this to.
|
|
|
|
To make this work you need to do things like this in the backend:
|
|
|
|
req->control_flags |= REQ_CONTROL_ASYNC;
|
|
|
|
that tells smbd that the backend has elected to reply later rather
|
|
than replying immediately. The backend must *only* do this if
|
|
req->async.send_fn is not NULL. If send_fn is NULL then it means that
|
|
the smbd front end cannot handle this function being replied to in an
|
|
async fashion.
|
|
|
|
If the backend does this then it is up to the backend to call
|
|
req->async.send_fn() when it is ready to reply. It the meantime smbd
|
|
puts the call on hold and goes back to answering other requests on the
|
|
socket.
|
|
|
|
Inside smbd you will find that there is code to support this. The most
|
|
obvious change is that smbd splits each SMB reply function into two
|
|
parts - just like the client library has a _send() and _recv()
|
|
function, so smbd has a _send() function and the parse function for
|
|
each SMB.
|
|
|
|
As an example go and have a look at reply_getatr_send() and
|
|
reply_getatr() in smbd/reply.c. Read them? Good.
|
|
|
|
Notice that reply_getatr() sets up the req->async structure to contain
|
|
the send function. Thats how the backend gets to do an async reply, it
|
|
calls this function when it is ready. Also notice that reply_getatr()
|
|
only does the parsing of the request, and does not do the reply
|
|
generation. That is done by the _send() function.
|
|
|
|
The only missing piece in the Samba4 right now that prevents it being
|
|
fully async is that it currently does the low level socket calls (read
|
|
and write on sockets) in a blocking fashion. It does use select() to
|
|
make it somewhat async, but if a client were to send a partial packet
|
|
then delay before sending the rest then smbd would be stuck waiting
|
|
for the second half of the packet.
|
|
|
|
To fix this I plan on making the socket calls async as well, which
|
|
luckily will not involve any API changes in the core of smbd or the
|
|
library. It just involves a little bit of extra code in clitransport.c
|
|
and smbd/request.c. As a side effect I hope that this will also reduce
|
|
the average number of system calls required to answer a request, so we
|
|
may see a performance improvement.
|
|
|
|
|
|
NTVFS
|
|
-----
|
|
|
|
One of the most noticeable changes in Samba4 is the introduction of
|
|
the NTVFS layer. This provided the initial motivation for the design
|
|
of Samba4 and in many ways lies at the heart of the design.
|
|
|
|
In Samba3 the main file serving process (smbd) combined the handling
|
|
of the SMB protocol with the mapping to POSIX semantics in the same
|
|
code. If you look in smbd/reply.c in Samba3 you see numerous places
|
|
where POSIX assumptions are mixed tightly with SMB parsing code. We
|
|
did have a VFS layer in Samba3, but it was a POSIX-like VFS layer, so
|
|
no matter how you wrote a plugin you could not bypass the POSIX
|
|
mapping decisions that had already been made before the VFS layer was
|
|
called.
|
|
|
|
In Samba4 things are quite different. All SMB parsing is performed in
|
|
the smbd front end, then fully parsed requests are passed to the NTVFS
|
|
backend. That backend makes any semantic mapping decisions and fills
|
|
in the 'out' portion of the request. The front end is then responsible
|
|
for putting those results into wire format and sending them to the
|
|
client.
|
|
|
|
Lets have a look at one of those request structures. Go and read the
|
|
definition of "union smb_write" and "enum write_level" in
|
|
include/smb_interfaces.h. (no, don't just skip reading it, really go
|
|
and read it. Yes, that means you!).
|
|
|
|
Notice the union? That's how Samba4 allows a single NTVFS backend
|
|
interface to handle the several different ways of doing a write
|
|
operation in the SMB protocol. Now lets look at one section of that
|
|
union:
|
|
|
|
/* SMBwriteX interface */
|
|
struct {
|
|
enum write_level level;
|
|
|
|
struct {
|
|
uint16 fnum;
|
|
SMB_BIG_UINT offset;
|
|
uint16 wmode;
|
|
uint16 remaining;
|
|
uint32 count;
|
|
const char *data;
|
|
} in;
|
|
struct {
|
|
uint32 nwritten;
|
|
uint16 remaining;
|
|
} out;
|
|
} writex;
|
|
|
|
see the "in" and "out" sections? The "in" section is for parameters
|
|
that the SMB client sends on the wire as part of the request. The smbd
|
|
front end parse code parses the wire request and fills in all those
|
|
parameters. It then calls the NTVFS interface which looks like this:
|
|
|
|
NTSTATUS (*write)(struct request_context *req, union smb_write *io);
|
|
|
|
and the NTVFS backend does the write request. The backend then fills
|
|
in the "out" section of the writex structure and gives the union back
|
|
to the front end (either by returning, or if done in an async fashion
|
|
then by calling the async send function. See the async discussion
|
|
elsewhere in this document).
|
|
|
|
The NTVFS backend knows which particular function is being requested
|
|
by looking at io->generic.level. Notice that this enum is also
|
|
repeated inside each of the sub-structures in the union, so the
|
|
backend could just as easily look at io->writex.level and would get
|
|
the same variable.
|
|
|
|
Notice also that some levels (such as splwrite) don't have an "out"
|
|
section. This happens because there is no return value apart from a
|
|
status code from those SMB calls.
|
|
|
|
So what about status codes? The status code is returned directly by
|
|
the backend NTVFS interface when the call is performed
|
|
synchronously. When performed asynchronously then the status code is
|
|
put into req->async.status before the req->async.send_fn() callback is
|
|
called.
|
|
|
|
Currently the most complete NTVFS backend is the CIFS backend. I don't
|
|
expect this backend will be used much in production, but it does
|
|
provide the ideal test case for our NTVFS design. As it offers the
|
|
full capabilities that are possible with a CIFS server we can be sure
|
|
that we don't have any gaping holes in our APIs, and that the front
|
|
end code is flexible enough to handle any advances in the NT style
|
|
feature sets of Unix filesystems that make come along.
|
|
|
|
|
|
Process Models
|
|
--------------
|
|
|
|
In Samba3 we supported just one process model. It just so happens that
|
|
the process model that Samba3 supported is the "right" one for most
|
|
users, but there are situations where this model wasn't ideal.
|
|
|
|
In Samba4 you can choose the smbd process model on the smbd command
|
|
line.
|
|
|
|
|
|
DCERPC binding strings
|
|
----------------------
|
|
|
|
When connecting to a dcerpc service you need to specify a binding
|
|
string.
|
|
|
|
The format is:
|
|
|
|
TRANSPORT:host[flags]
|
|
|
|
where TRANSPORT is either ncacn_np for SMB or ncacn_ip_tcp for RPC/TCP
|
|
|
|
"host" is an IP or hostname or netbios name. If the binding string
|
|
identifies the server side of an endpoint, "host" may be an empty
|
|
string.
|
|
|
|
"flags" can include a SMB pipe name if using the ncacn_np transport or
|
|
a TCP port number if using the ncacn_ip_tcp transport, otherwise they
|
|
will be auto-determined.
|
|
|
|
other recognised flags are:
|
|
|
|
sign : enable ntlmssp signing
|
|
seal : enable ntlmssp sealing
|
|
connect : enable rpc connect level auth (auth, but no sign or seal)
|
|
validate: enable the NDR validator
|
|
print: enable debugging of the packets
|
|
bigendian: use bigendian RPC
|
|
padcheck: check reply data for non-zero pad bytes
|
|
|
|
|
|
For example, these all connect to the samr pipe:
|
|
|
|
ncacn_np:myserver
|
|
ncacn_np:myserver[samr]
|
|
ncacn_np:myserver[\pipe\samr]
|
|
ncacn_np:myserver[/pipe/samr]
|
|
ncacn_np:myserver[samr,sign,print]
|
|
ncacn_np:myserver[\pipe\samr,sign,seal,bigendian]
|
|
ncacn_np:myserver[/pipe/samr,seal,validate]
|
|
ncacn_np:
|
|
ncacn_np:[/pipe/samr]
|
|
|
|
ncacn_ip_tcp:myserver
|
|
ncacn_ip_tcp:myserver[1024]
|
|
ncacn_ip_tcp:myserver[1024,sign,seal]
|
|
|
|
|
|
IDEA: Maybe extend UNC names like this?
|
|
|
|
smbclient //server/share
|
|
smbclient //server/share[sign,seal,spnego]
|
|
|
|
DCERPC Handles
|
|
--------------
|
|
The various handles that are used in the RPC servers should be created and
|
|
fetch using the dcesrv_handle_* functions.
|
|
|
|
Use dcesrv_handle_new(struct dcesrv_connection *, uint8 handle_type) to obtain
|
|
a new handle of the specified type. Handle types are unique within each
|
|
pipe.
|
|
|
|
The handle can later be fetched again using
|
|
struct dcesrv_handle *dcesrv_handle_fetch(struct dcesrv_connection *dce_conn, struct policy_handle *p, uint8 handle_type)
|
|
and destroyed by dcesrv_handle_destroy(struct dcesrv_handle *).
|
|
|
|
User data should be stored in the 'data' member of the dcesrv_handle struct.
|
|
|
|
|
|
MSRPC
|
|
-----
|
|
|
|
|
|
|
|
- ntvfs
|
|
- testing
|
|
- command line handling
|
|
- libcli structure
|
|
- posix reliance
|
|
- uid/gid handling
|
|
- process models
|
|
- static data
|
|
- msrpc
|
|
|
|
|
|
don't zero structures! avoid ZERO_STRUCT() and talloc_zero()
|
|
|
|
|
|
GMT vs TZ in printout of QFILEINFO timezones
|
|
|
|
put in full UNC path in tconx
|
|
|
|
test timezone handling by using a server in different zone from client
|
|
|
|
do {} while (0) system
|
|
|
|
NT_STATUS_IS_OK() is NOT the opposite of NT_STATUS_IS_ERR()
|
|
|
|
need to implement secondary parts of trans2 and nttrans in server and
|
|
client
|
|
|
|
document access_mask in openx reply
|
|
|
|
check all capabilities and flag1, flag2 fields (eg. EAs)
|
|
|
|
large files -> pass thru levels
|
|
|
|
setpathinfo is very fussy about null termination of the file name
|
|
|
|
the overwrite flag doesn't seem to work on setpathinfo RENAME_INFORMATION
|
|
|
|
END_OF_FILE_INFORMATION and ALLOCATION_INFORMATION don't seem to work
|
|
via setpathinfo
|
|
|
|
on w2k3 setpathinfo DISPOSITION_INFORMATION fails, but does have an
|
|
effect. It leaves the file with SHARING_VIOLATION.
|
|
|
|
on w2k3 trans2 setpathinfo with any invalid low numbered level causes
|
|
the file to get into a state where DELETE_PENDING is reported, and the
|
|
file cannot be deleted until you reboot
|
|
|
|
trans2 qpathinfo doesn't see the delete_pending flag correctly, but
|
|
qfileinfo does!
|
|
|
|
get rid of pstring, fstring, strtok
|
|
|
|
add programming documentation note about lp_set_cmdline()
|
|
|
|
need to add a wct checking function in all client parsing code,
|
|
similar to REQ_CHECK_WCT()
|
|
|
|
need to make sure that NTTIME is a round number of seconds when
|
|
converted from time_t
|
|
|
|
not using a zero next offset in SMB_FILE_STREAM_INFORMATION for last
|
|
entry causes explorer exception under win2000
|
|
|
|
|
|
if the server sets the session key the same for a second SMB socket as
|
|
an initial socket then the client will not re-authenticate, it will go
|
|
straight to a tconx, skipping session setup and will use all the
|
|
existing parameters! This allows two sockets with the same keys!?
|
|
|
|
|
|
removed blocking lock code, we now queue the whole request the same as
|
|
we queue any other pending request. This allows for things like a
|
|
close() while a pending blocking lock is being processed to operate
|
|
sanely.
|
|
|
|
disabled change notify code
|
|
|
|
disabled oplock code
|
|
|
|
|
|
|
|
MILESTONES
|
|
==========
|
|
|
|
|
|
client library and test code
|
|
----------------------------
|
|
|
|
convert client library to new structure
|
|
get smbtorture working
|
|
get smbclient working
|
|
expand client library for all requests
|
|
write per-request test suite
|
|
gentest randomised test suite
|
|
separate client code as a library for non-Samba use
|
|
|
|
server code
|
|
-----------
|
|
add remaining core SMB requests
|
|
add IPC layer
|
|
add nttrans layer
|
|
add rpc layer
|
|
fix auth models (share, server, rpc)
|
|
get net command working
|
|
connect CIFS backend to server level auth
|
|
get nmbd working
|
|
get winbindd working
|
|
reconnect printing code
|
|
restore removed smbd options
|
|
add smb.conf macro substitution code
|
|
add async backend notification
|
|
add generic timer event mechanism
|
|
|
|
clustering code
|
|
---------------
|
|
|
|
write CIFS backend
|
|
new server models (break 1-1)
|
|
test clustered models
|
|
add fulcrum statistics gathering
|
|
|
|
docs
|
|
----
|
|
|
|
conference paper
|
|
developer docs
|
|
|
|
svn instructions
|
|
|
|
Ideas
|
|
-----
|
|
|
|
- store all config in config.ldb
|
|
|
|
- load from smb.conf if modtime changes
|
|
|
|
- dump full system config with ldbsearch
|
|
|
|
- will need the ability to form a ldif difference file
|
|
|
|
- advanced web admin via a web ldb editor
|
|
|
|
- normal web admin via web forms -> ldif
|
|
|
|
- config.ldb will replace smb.conf, secrets.tdb, shares.tdb etc
|
|
|
|
- subsystems in smbd will load config parameters for a share
|
|
using ldbsearch at tconx time
|
|
|
|
- need a loadparm equivalent module that provides parameter defaults
|
|
|
|
- start smbd like this: "smbd -C tdb://etc/samba/config.ldb" or
|
|
"smbd -C ldapi://var/run/ldapi"
|
|
|
|
- write a tool that generates a template ldap schema from an existing
|
|
ldb+tdb file
|
|
|
|
- no need to HUP smbd to reload config
|
|
|
|
- how to handle configuration comments? same problem as SWAT
|
|
|
|
|
|
BUGS:
|
|
add a test case for last_entry_offset in trans2 find interfaces
|
|
conn refused
|
|
connect -> errno
|
|
no 137 resolution not possible
|
|
should not fallback to anon when pass supplied
|
|
should check pass-thu cap bit, and skip lots of tests
|
|
possibly allow the test suite to say "allow oversized replies" for
|
|
trans2 and other calls
|
|
handle servers that don't have the setattre call in torture
|
|
add max file coponent length test and max path len test
|
|
|
|
case-insenstive idea:
|
|
all filenames on disk lowercase
|
|
real case in extended attribute
|
|
keep cache of what dirs are all lowercase
|
|
when searching for name, don't search if dir is definately all lowercase
|
|
when creating file, use dnotify to tell if someone else creates at
|
|
same time
|
|
|
|
solve del *.* idea:
|
|
make mangle cache dynamic size
|
|
fill during a dir scan
|
|
setup a timer
|
|
destroy cache after 30 sec
|
|
destroy if a 2nd dir scan happens on same dir
|