Hello,
I was trying to remove the limit on the maximum MTU for the ethertap
device (it uses the default ethernet routines which limit it to 1500). I
have successfully altered the ethertap driver (patch attached), but
there's a problem with the netlink routines. It appears that the maximum
message size is limitted by some kind of malloc that appears in
linux/net/netlink/af_netlink.c line 732:
skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
Where according to /usr/include/linux/netlink.h:
#define NLMSG_GOODSIZE (PAGE_SIZE - ((sizeof(struct sk_buff)+0xF)&~0xF))
I guess this malloc enlarges the size of the sk to the next page boundary
but then again, I might be completely wrong. Nevertheless, this seems to
limit the size of the packets that are sent to userspace to somewhere near
PAGE_SIZE. I'd like to see that restriction removed, but I don't know if
this is possible or perhaps dangerous?
Met vriendelijke groet,
Guus Sliepen.
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This archive was generated by hypermail 2b29 : Fri Jun 23 2000 - 21:00:21 EST