search for: nbd_can_df

Rich recently patched things to generate one man page per function rather than libnbd-api.3 (nice), but in doing so got stumped by a problem with a fresh git clone (automake fails for any 'include' directive that does not already exist). I've figured out how to hack around it, but the hack requires GNU make. We already use GNU make constructs elsewhere (such as $(wildcard)), but

...;, cmd_flags) ]; Do we want to use this as a chance to document which flags a given API supports? For example, pread supports DF but not FUA, REQ_ONE, or MAY_TRIM. Then again, there's still a dynamic element - the API supports the DF flag for compilation, but the server must also support it (nbd_can_df) before you can use it. So any further restrictions we decide to encode in the generator rather (or in addition) to restrictions in lib/rw.c can be a later patch. > +++ b/ocaml/tests/test_405_pread_structured.ml > @@ -54,11 +54,13 @@ let () = > NBD.pread_structured nbd buf 0_L (f 42);...

...atures that require the newstyle protocol, and thus be sure that an oldstyle server did not thwart encryption. Either of the following extension tests will prove that a newstyle server is present (unfortunately, this does not help for a newstyle server that does not support either extension): - If nbd_can_df(h) returns true. - If the client requests nbd_add_meta_context(h, context) prior to connection, then nbd_can_meta_context(h, context) returns true; the most commonly supported context is LIBNBD_CONTEXT_BASE_ALLOCATION. Test if libnbd is vulnerable ---------------------------- Run the following co...

...tes = [ Created ]; + first_version = (1, 2); + shortdesc = "control use of structured replies"; + longdesc = "\ +By default, libnbd tries to negotiate structured replies with the +server, as this protocol extension must be in use before +C<nbd_can_meta_context> or C<nbd_can_df> can return true. However, +for integration testing, it can be useful to clear this flag +rather than find a way to alter the server to fail the negotiation +request."; + see_also = ["L<nbd_get_request_structured_replies(3)>"; + "L<nbd_can_meta_con...

...+C<LIBNBD_CMD_FLAG_DF> meaning that the server should not fragment +a read reply across more than one packet, even if using multiple +packets would otherwise allow a more efficient representation of +holes contained in the region (if that is supported - some servers +cannot do this, see C<nbd_can_df>)."; }; "pwrite", { @@ -1774,6 +1790,7 @@ let constants = [ "CMD_FLAG_FUA", 1 lsl 0; "CMD_FLAG_NO_HOLE", 1 lsl 1; + "CMD_FLAG_DF", 1 lsl 2; "CMD_FLAG_REQ_ONE", 1 lsl 3; ] diff --git a/lib/flags.c b/li...

...;; see_also = ["L<nbd_get_request_structured_replies(3)>"; "L<nbd_set_handshake_flags(3)>"; + "L<nbd_get_structured_replies_negotiated(3)>"; "L<nbd_can_meta_context(3)>"; "L<nbd_can_df(3)>"]; }; @@ -1322,10 +1323,26 @@ request."; shortdesc = "see if structured replies are attempted"; longdesc = "\ Return the state of the request structured replies flag on this -handle. Note that this only reports whether the client attempts -to negotiat...

...\ - nbd_set_tls_username \ - nbd_get_tls_username \ - nbd_set_tls_psk_file \ - nbd_add_meta_context \ - nbd_connect_uri \ - nbd_connect_unix \ - nbd_connect_tcp \ - nbd_connect_command \ - nbd_is_read_only \ - nbd_can_flush \ - nbd_can_fua \ - nbd_is_rotational \ - nbd_can_trim \ - nbd_can_zero \ - nbd_can_df \ - nbd_can_multi_conn \ - nbd_can_cache \ - nbd_can_meta_context \ - nbd_get_size \ - nbd_pread \ - nbd_pread_structured \ - nbd_pwrite \ - nbd_shutdown \ - nbd_flush \ - nbd_trim \ - nbd_cache \ - nbd_zero \ - nbd_block_status \ - nbd_poll \ - nbd_aio_connect \ - nbd_aio_connect_uri \ - nbd_aio_c...

...ather than find a way to alter the server to fail the negotiation request."; see_also = ["L<nbd_get_request_structured_replies(3)>"; + "L<nbd_set_handshake_flags(3)>"; "L<nbd_can_meta_context(3)>"; "L<nbd_can_df(3)>"]; }; @@ -1277,6 +1285,66 @@ able to honor that request"; see_also = ["L<nbd_set_request_structured_replies(3)>"]; }; + "set_handshake_flags", { + default_call with + args = [ Flags ("flags", handshake_flags) ]; ret = RErr; +...

...\ + nbd_set_tls_username \ + nbd_get_tls_username \ + nbd_set_tls_psk_file \ + nbd_add_meta_context \ + nbd_connect_uri \ + nbd_connect_unix \ + nbd_connect_tcp \ + nbd_connect_command \ + nbd_is_read_only \ + nbd_can_flush \ + nbd_can_fua \ + nbd_is_rotational \ + nbd_can_trim \ + nbd_can_zero \ + nbd_can_df \ + nbd_can_multi_conn \ + nbd_can_cache \ + nbd_can_meta_context \ + nbd_get_size \ + nbd_pread \ + nbd_pread_structured \ + nbd_pwrite \ + nbd_shutdown \ + nbd_flush \ + nbd_trim \ + nbd_cache \ + nbd_zero \ + nbd_block_status \ + nbd_poll \ + nbd_aio_connect \ + nbd_aio_connect_uri \ + nbd_aio_c...

...now (it exists for future NBD -protocol extensions)."; +The C<flags> parameter may be C<0> for no flags, or may contain +C<LIBNBD_CMD_FLAG_DF> meaning that the server should not reply with +more than one fragment (if that is supported - some servers cannot do +this, see C<nbd_can_df>). Libnbd does not validate that the server +actually obeys the flag."; }; "pwrite", { @@ -2025,6 +2040,7 @@ let constants = [ "CMD_FLAG_FUA", 1 lsl 0; "CMD_FLAG_NO_HOLE", 1 lsl 1; + "CMD_FLAG_DF", 1 lsl 2; "CM...

...les/fetch-first-sector.c"; }; @@ -1646,9 +1670,11 @@ The C<flags> parameter may be C<0> for no flags, or may contain C<LIBNBD_CMD_FLAG_DF> meaning that the server should not reply with more than one fragment (if that is supported - some servers cannot do this, see L<nbd_can_df(3)>). Libnbd does not validate that the server -actually obeys the flag."; +actually obeys the flag." +^ strict_call_description; see_also = [Link "can_df"; Link "pread"; - Link "aio_pread_structured"; Link "get_block_size"];...

...; > }; > > @@ -1646,9 +1670,11 @@ The C<flags> parameter may be C<0> for no flags, or may contain > C<LIBNBD_CMD_FLAG_DF> meaning that the server should not reply with > more than one fragment (if that is supported - some servers cannot do > this, see L<nbd_can_df(3)>). Libnbd does not validate that the server > -actually obeys the flag."; > +actually obeys the flag." > +^ strict_call_description; > see_also = [Link "can_df"; Link "pread"; > - Link "aio_pread_structured"; Link &quo...

Necessary when writing a client that wants to avoid unnecessary EINVAL errors from sending unaligned requests. At some point, we may want to add synchronous convenience API wrappers that do request splitting or read-modify-write to obey server constraints while still appearing to the library client as accepting any possible request. But such a wrapper should only be synchronous and not copied to

RFC because this is an API break, but we haven't declared stable API yet. If we like it, I'm working on using libnbd to implement the nbdkit-nbd plugin; knowing whether it is API version 0.1 or 0.2 will be useful. I also dabbled with allowing optional parameters in python, although my OCaml is weak enough that there may be cleaner ways to approach that. Eric Blake (4): api: Add flags

Since v1: - rebase to applied patches - split out support for Int in callbacks - sort of test that callbacks work in OCaml (see comment in patch 5) - rename API to nbd_pread_structured - expose error as explicit parameter to callback Eric Blake (5): generator: Allow Int in callbacks states: Wire in a read callback states: Add nbd_pread_structured API states: Add tests for

In v2: - now based on my proposal to add LIBNBD_SHUTDOWN_IMMEDIATE - four flags instead of two: STRICT_FLAGS is new (patch 4), and STRICT_BOUNDS is separate from STRICT_ZERO_SIZE (patch 5) - various refactorings for more shared code and less duplication Eric Blake (5): api: Add xxx_MASK constant for each Flags type generator: Refactor filtering of accepted OFlags api: Add

This largish series adds several new features to the generator. Enum maps to enumerated types (like enum in C). The only current use for this is replacing the nbd_set_tls (nbd, 0/1/2) parameter with LIBNBD_TLS_DISABLE, LIBNBD_TLS_ALLOW, LIBNBD_TLS_REQUIRE (and natural equivalents in other programming languages). Flags maps to any uint32_t bitmask. It is basically a non-optional, generalized

I've mentioned this topic before (in fact, the idea of adding NBD_CMD_FLAG_DF was first mentioned at [1]), but finally finished enough of an implementation to feel confident in posting it. I'd still like to add something under examples/ that uses the new API to implement strict checking of a server's structured replies read implementation (ensure that a server never sends data after