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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [Patch] vnet-module ( for 3.1 && unstable )
On 7/16/07, Robert Valentan <R.Valentan@xxxxxxxxxxxxx> wrote: Zhu Han schrieb: > Hi, Robert, > > Here are some questions: > > 1) If we just pull Eth Header and IP header, does it reach the > position out of the head room? I dont' observe it before. The __skb_pull in include/linux/skbuff.h has a BUG_ON, which was always "active". The problem are not the header of the received packet, but the encapsed header. Without the change, my systems are always been killed by the BUG_ON in skbuff.h To observe it: use a vnet with peer's on different networks, eg each part in an other datacenter... The BUG_ON only wakes up when you pulls data more than head room contained. Sometime s the vnet header will be put to fragmented page instead of in head room. So when pull out the vnet header, it will hit on the BUG_ON. That's what you observed, I'm afraid. > 2) You don't move_addr_to_kernel/move_addr_to_user, you just need > change_fs to KERNEL_DS and then change it back. ? The UDP & IP-header was not always changeable on received packets after pulling data, possible there is a better (or nicer) way.. I mean you don't need move_addr_to_kernel/move_addr_to_user. Whatever, you code is already in kernel mode. > 3) Why not use "struct sock" directly to manipulate the socket instead > of using int file descriptor? I had want only to get it to work, without writing it new, i changed only the code, to make it work on systms without sys-socketcall. I don't think, that anyone had used vnet_module in 3.* before. With my patch, the vnet_module is now working local, in local-net and with peer's, as long you need no security-option. I tested it on i386 and x86_64 systems. Unfortunately, I'm pretty sure vnet was broken serveral months ago. When I tried to use it, I have to build my own patch. regards Robert Valentan > On 7/16/07, Robert Valentan <R.Valentan@xxxxxxxxxxxxx> wrote: >> Hallo! >> >> The attached patch makes the vnet-module working for i386 >> and x86_64. (I had no other systems for testing) >> (My patch from 6.6.2007 is included) >> >> - x86_64: the x86-64 kernel has __ARCH_WANT_SYS_SOCKETCALL >> defined, but has no socketcall. Replacing the _syscall's >> to a working one. >> >> - moves the "skb_pull" function from kernel to skb_util.c >> because pulling in the data will rise a "BUG_ON" in the >> kernel. The kernel-function does not allow to pull into >> the payload! >> >> - the skb_buff is not always possible to modify a received >> buffer to send it again to the network. >> (vnet_forward.c and etherip.c) The code now work's.. >> I think with no or less time-penalty. -- best regards, hanzhu _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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