1. 25 9月, 2010 1 次提交
    • E
      ip: take care of last fragment in ip_append_data · 59104f06
      Eric Dumazet 提交于
      While investigating a bit, I found ip_fragment() slow path was taken
      because ip_append_data() provides following layout for a send(MTU +
      N*(MTU - 20)) syscall :
      
      - one skb with 1500 (mtu) bytes
      - N fragments of 1480 (mtu-20) bytes (before adding IP header)
      last fragment gets 17 bytes of trail data because of following bit:
      
      	if (datalen == length + fraggap)
      		alloclen += rt->dst.trailer_len;
      
      Then esp4 adds 16 bytes of data (while trailer_len is 17... hmm...
      another bug ?)
      
      In ip_fragment(), we notice last fragment is too big (1496 + 20) > mtu,
      so we take slow path, building another skb chain.
      
      In order to avoid taking slow path, we should correct ip_append_data()
      to make sure last fragment has real trail space, under mtu...
      Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      59104f06
  2. 24 9月, 2010 4 次提交
  3. 23 9月, 2010 7 次提交
  4. 22 9月, 2010 24 次提交
  5. 21 9月, 2010 4 次提交