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[lwip-devel] Bypassing checksums
From: |
Gisle Vanem |
Subject: |
[lwip-devel] Bypassing checksums |
Date: |
Wed, 18 Jan 2017 17:29:20 +0100 |
User-agent: |
Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 |
While building lwIP on Windows and testing using e.g. Google Chrome
on the same Windows machine I build lwIP on, the lwIP application sense-fully
ignores incoming packets with wrong checksums.
AFAICS, since IP+UDP+TCP checksum routines are most often implemented in the
NIC driver, packets coming from 'WinPap' will have wrong (no?) checksums. Or
is there another reason?
Hence in my lwipopts.h I set these to 0 to ignore wrong checksums:
#if (LWIP_DEBUG > 0)
#define CHECKSUM_CHECK_IP 0
#define CHECKSUM_CHECK_TCP 0
#define CHECKSUM_CHECK_UDP 0
#define CHECKSUM_CHECK_ICMP 0
#define CHECKSUM_CHECK_ICMP6 0
...
#endif
Without modifying the NIC-driver to NOT use this checksum
off-loading feature, is there a better way for my lwip test-app
to accept packets from my local machine?
Is there was a way to accept wrong checksums from a certain
source IP only? That would be perfect.
--
--gv
- [lwip-devel] Bypassing checksums,
Gisle Vanem <=