Messages in this thread | | | Subject | Re: Broken commit: [NETFILTER]: ipt_REJECT: remove largely duplicate route_reverse function | From | Krzysztof Halasa <> | Date | Wed, 29 Nov 2006 00:56:35 +0100 |
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Patrick McHardy <kaber@trash.net> writes:
> It might be the case that your network device has a > hard_header_len > LL_MAX_HEADER, which could trigger > a corruption.
Hmm... GRE tunnels add 24 bytes... I just noticed the following code in include/linux/netdevice.h:
/* * Compute the worst case header length according to the protocols * used. */ #if !defined(CONFIG_AX25) && !defined(CONFIG_AX25_MODULE) && !defined(CONFIG_TR) #define LL_MAX_HEADER 32 #else #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) #define LL_MAX_HEADER 96 #else #define LL_MAX_HEADER 48 #endif #endif
#if !defined(CONFIG_NET_IPIP) && \ !defined(CONFIG_IPV6) && !defined(CONFIG_IPV6_MODULE) #define MAX_HEADER LL_MAX_HEADER #else #define MAX_HEADER (LL_MAX_HEADER + 48) #endif
I don't use AX25, Token Ring, the old IPIP tunnels nor IPv6 here, but I wonder if GRE tunnel (which is basically another, more compatible form of IPIP) need the same treatment as IPIP.
I've confirmed that REJECTs over GRE tunnel caused that corruption.
> Please try this patch on top of the REJECT patch (ideally after > verifying that the REJECT patch is really introducing the > corruption).
That was certain. The patch fixed the problem, confirmed with current git tree as well. Thanks for looking at it.
I'm not sure about LL_MAX_HEADER (and/or MAX_HEADER) though. Should it be changed as well?
There are many devices adding data to header space, perhaps tacking devices doesn't count as the skb is being linearized in dev->hard_start_xmit() or equivalent path? -- Krzysztof Halasa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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