Date: Mon, 06 Feb 2006 14:21:09 -0800 From: Nate Lawson <nate@root.org> To: Oleg Bulyzhin <oleg@FreeBSD.org> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, Alan Cox <alc@cs.rice.edu>, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/dev/bge if_bge.c Message-ID: <43E7CBD5.5090203@root.org> In-Reply-To: <20060206221141.GA57775@lath.rinet.ru> References: <200602020958.k129wWtc066930@repoman.freebsd.org> <20060202100637.GB24350@lath.rinet.ru> <20060205235817.GQ5499@cs.rice.edu> <20060206221141.GA57775@lath.rinet.ru>
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Oleg Bulyzhin wrote:
> On Sun, Feb 05, 2006 at 05:58:17PM -0600, Alan Cox wrote:
>>Unfortunately, it also breaks NFS over UDP. Let me know if you need
>>details.
>>
>>Alan
>
>
> Fix attached. It's not bge problem it's five years old bug in ip_reass().
>
> Index: ip_input.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/netinet/ip_input.c,v
> retrieving revision 1.314
> diff -u -r1.314 ip_input.c
> --- ip_input.c 2 Feb 2006 03:13:15 -0000 1.314
> +++ ip_input.c 6 Feb 2006 21:44:45 -0000
> @@ -982,10 +982,12 @@
> nq = q->m_nextpkt;
> q->m_nextpkt = NULL;
> for (q = nq; q != NULL; q = nq) {
> + int sum;
It's not good to declare local variables in the for() context. It's a
style(9) bug and also costs an extra instruction or two (to decrement
the stack pointer twice).
> nq = q->m_nextpkt;
> q->m_nextpkt = NULL;
> m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
> - m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
> + sum = m->m_pkthdr.csum_data + q->m_pkthdr.csum_data;
> + m->m_pkthdr.csum_data = (sum & 0xffff) + (sum >> 16);
> m_cat(m, q);
> }
> #ifdef MAC
I'm not familiar with this code. So m->m_pkthdr.csum_data is 32 bits?
Couldn't the same thing be achieved with making it 16 bits since the add
will wrap normally?
--
Nate
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