Date: Tue, 29 May 2001 22:11:07 +0200 From: Jesper Skriver <jesper@skriver.dk> To: Bob Willcox <bob@immure.com> Cc: hackers list <freebsd-hackers@freebsd.org> Subject: Re: How to disable software TCP checksumming? Message-ID: <20010529221107.C49875@skriver.dk> In-Reply-To: <20010529144114.I19771@luke.immure.com>; from bob@immure.com on Tue, May 29, 2001 at 02:41:14PM -0500 References: <20010529144114.I19771@luke.immure.com>
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On Tue, May 29, 2001 at 02:41:14PM -0500, Bob Willcox wrote:
> Hi,
>
> I am working on a device driver for a GSN adapter that has hardware CRC
> checking and need to know if there is a way to disable the software CRC
> checking for TCP? This is on a FreeBSD 4.2-stable system.
Not without modifying the source, the below should do it from a
quick look.
Index: src/sys/netinet/tcp_input.c
===================================================================
RCS file: /home/ncvs/src/sys/netinet/tcp_input.c,v
retrieving revision 1.130
diff -u -r1.130 tcp_input.c
--- src/sys/netinet/tcp_input.c 2001/05/29 19:54:45 1.130
+++ src/sys/netinet/tcp_input.c 2001/05/29 20:07:22
@@ -401,6 +401,7 @@
th = (struct tcphdr *)((caddr_t)ip + off0);
tlen = ip->ip_len;
+#if 0
if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
th->th_sum = m->m_pkthdr.csum_data;
@@ -423,6 +424,7 @@
tcpstat.tcps_rcvbadsum++;
goto drop;
}
+#endif
#ifdef INET6
/* Re-initialization for later version check */
ip->ip_v = IPVERSION;
/Jesper
--
Jesper Skriver, jesper(at)skriver(dot)dk - CCIE #5456
Work: Network manager @ AS3292 (Tele Danmark DataNetworks)
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