yoann padioleaus report on 9fans:
> I think I’ve found a bug in the network stack.
> in 9/ip/ip.h there is
> struct Ipht
> {
> Lock;
> Iphash *tab[Nipht];
> };
>
> where Night is 521,
>
> but then in 9/ip/ipaux.c there is
>
> ulong
> iphash(uchar *sa, ushort sp, uchar *da, ushort dp)
> {
> return ((sa[IPaddrlen-1]<<24) ^ (sp << 16) ^ (da[IPaddrlen-1]<<8) ^ dp ) % Nhash;
> }
>
> where Nhash is just 64,
prevent double sleep():
callers to sleep() need to be serialized as there can only
be one process sleeping at a time. plrlock and plwlock do
this.
wait for dma to complete in plwrite():
we have to wait for the dma to complete before touching
plbuf again.
maintain COPEN flag in archopen()/archclose():
when open fails because it was in use, clear the COPEN
flag, so archclose() wont screw stuff up.
try the handle buffer in reverse order looking for plan9.ini
to find plan9 partition (9fat). when that fails, we'll default
to the first handle which should be the esp.
there where two problems with blank (-b flag):
we did not update the backup header when there was already a valid
backup header in place. we always want to initialize a new backup header
in blank mode!
we now also check the backup header matches the primary (or the other
way arround depending on which header could be read), reporting any
mismatches and restoring the backup from the data of the primary.
the protective mbr needs to start at sector 1 not 0 (apparently, this
matters for ovmf).
efi systems may use traditional dos partition table
with an esp (efi system partition). otherwise, honor
the protective mbr partition (0xEE) and exit when we
encounter it.
- make sure disk file is an actual file and not a directory, log or empty file
- sanity check: file has to be at least one sector to be a disk
- simplify error handling using freedisk()
- make UU() shorter by using long long constant to encode node field
- store Flag as a mask, not as a shift count
- put the attributes before the name in cmdsum() as it is fixed length
often, documents specify charsets but are really utf-8 encoded.
we now try to decode as utf-8 and only if that fails assume
the charset specified in the document.
make digest_certinfo() return the digest length, otherwise
return -1 as an error and handle it in the callers.
pass expected digest length to verify_signature() and
check digest length from certificate! make sure we wont
run off the buffer.
fix newlines in error prints of X509dump().
this implements SHA2 (224, 256, 384, 512) signature algorithms and
uses sha256WithRSAEncryption for X509req() and X509gen() instead
of oid_md5WithRSAEncryption.
the compiler used to skip zero initialization when initializer
list was given not covering unspecified elements. now we zero
all non explicitely initialized elements. for example:
typedef struct F F;
struct F
{
int a;
int b;
int c;
};
void
main(void)
{
char a[16] = { 1, 2, 3 }; /* a[3..15] initialized to zero */
F f = { .b = 1 }; /* f.a, f.c initialized to zero */
}
the emited code that initializes local variables did not handle
unaligned data causing stack corruption, affecting code like:
void main(void)
{
char a[9] = {0};
}
this change will emit code that does byte stores for the unaligned
bytes and also handles small objects (<= 16 bytes) without branches.
tlsClient() now can optionally send the server_name in the ClientHello
message by setting the TLSconn.serverName. This is required for some
https sites.
using /proc/$pid/mem to access vga bios is not portable and crashes
sgi machines when aux/vga is run. instead, try /dev/realmodemem
first (provided by realemu), then #v/vgabios.
this allows extracting tar archives that use longnames extension,
where the real filename is stored in a special entry with
linkflag == 'L' before the file entry. also skip longlink entries
with linkflag == 'K'.
David du Colombier wrote:
> The slowness issue only appears on the loopback, because
> it provides a 16384 MTU.
>
> There is an old bug in the Plan 9 TCP stack, were the TCP
> MSS doesn't take account the MTU for incoming connections.
>
> I originally fixed this issue in January 2015 for the Plan 9
> port on Google Compute Engine. On GCE, there is an unusual
> 1460 MTU.
>
> The Plan 9 TCP stack defines a default 1460 MSS corresponding
> to a 1500 MTU. Then, the MSS is fixed according to the MTU
> for outgoing connections, but not incoming connections.
>
> On GCE, this issue leads to IP fragmentation, but GCE didn't
> handle IP fragmentation properly, so the connections
> were dropped.
>
> On the loopback medium, I suppose this is the opposite issue.
> Since the TCP stack didn't fix the MSS in the incoming
> connection, the programs sent multiple small 1500 bytes
> IP packets instead of large 16384 IP packets, but I don't
> know why it leads to such a slowdown.
i made a mistake here as this change breaks the arm and mips compilers
which lack an optimiation in xcom() that folds constant pointer arithmetic
into the offset. on arm, the a node is a complex expression with op OADD of
type TIND but the test rejected the (valid) pointer arithmetic.
instead, we now test for the operations which cannot be constant instead
of using the type as a proxy.
mischief spotted that the only way for listeners to go away was
truncating (but not removing) a service script. this is wrong and
not as described in the manpage.
this change makes removing (or truncating) a listen script stop
the listener.
scandir() first marks all current announces, then reads the service
directory adding announces which will clear the marks for the ones
already there or add a new unmarked one. finally, we shoot down and
remove all still marked announces.
