Re: [PATCH v3 05/10] pack-protocol: fix maximum pkt-line size

From: Lars Schneider <larsxschneider@gmail.com>
Date: Aug 1, 2016, 12:23 UTC
Message-ID: <B8F75E2C-2E85-4E91-B51F-90C3BF238072@gmail.com>
In-Reply-To: <cb6721b8-2a6a-deb1-2fc7-59399d118cec@gmail.com>

Show 10 quoted lines

> On 30 Jul 2016, at 15:58, Jakub Narębski <jnareb@gmail.com> wrote:
> 
> W dniu 30.07.2016 o 01:37, larsxschneider@gmail.com pisze:
>> From: Lars Schneider <larsxschneider@gmail.com>
>> 
>> According to LARGE_PACKET_MAX in pkt-line.h the maximal lenght of a
>> pkt-line packet is 65520 bytes. The pkt-line header takes 4 bytes and
>> therefore the pkt-line data component must not exceed 65516 bytes.
> 
> s/lenght/length/

Thanks!

> Is it maximum length of pkt-line packet, or maximum length of data
> that can be send in a packet?

65520 is the maximum length of a pkt-line.

> With 4 hex digits, maximal length if pkt-line packet (together
> with length) is ffff_16, that is 2^16-1 = 65535.  Where does the
> number 65520 comes from?

Historic reasons, I guess? However, it won't be changed. See response from Peff here: http://public-inbox.org/git/20160726134257.GB19277%40sigill.intra.peff.net/

Show 26 quoted lines

> 
>> 
>> Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
>> ---
>> Documentation/technical/protocol-common.txt | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>> 
>> diff --git a/Documentation/technical/protocol-common.txt b/Documentation/technical/protocol-common.txt
>> index bf30167..ecedb34 100644
>> --- a/Documentation/technical/protocol-common.txt
>> +++ b/Documentation/technical/protocol-common.txt
>> @@ -67,9 +67,9 @@ with non-binary data the same whether or not they contain the trailing
>> LF (stripping the LF if present, and not complaining when it is
>> missing).
>> 
>> -The maximum length of a pkt-line's data component is 65520 bytes.
>> -Implementations MUST NOT send pkt-line whose length exceeds 65524
>> -(65520 bytes of payload + 4 bytes of length data).
>> +The maximum length of a pkt-line's data component is 65516 bytes.
>> +Implementations MUST NOT send pkt-line whose length exceeds 65520
>> +(65516 bytes of payload + 4 bytes of length data).
>> 
>> Implementations SHOULD NOT send an empty pkt-line ("0004").
>> 
>> 
>