tcp_zerocopy_maxfrags.pkt

  1// SPDX-License-Identifier: GPL-2.0
  2// tcp_MAX_SKB_FRAGS test
  3//
  4// Verify that sending an iovec of tcp_MAX_SKB_FRAGS + 1 elements will
  5// 1) fit in a single packet without zerocopy
  6// 2) spill over into a second packet with zerocopy,
  7//    because each iovec element becomes a frag
  8// 3) the PSH bit is set on an skb when it runs out of fragments
  9
 10--send_omit_free	// do not reuse send buffers with zerocopy
 11
 12`./defaults.sh`
 13
 14    0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
 15   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
 16   +0 setsockopt(3, SOL_SOCKET, SO_ZEROCOPY, [1], 4) = 0
 17
 18   // Each pinned zerocopy page is fully accounted to skb->truesize.
 19   // This test generates a worst case packet with each frag storing
 20   // one byte, but increasing truesize with a page (64KB on PPC).
 21   +0 setsockopt(3, SOL_SOCKET, SO_SNDBUF, [2000000], 4) = 0
 22
 23   +0 bind(3, ..., ...) = 0
 24   +0 listen(3, 1) = 0
 25
 26   +0 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7>
 27   +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>
 28   +0 < . 1:1(0) ack 1 win 257
 29
 30   +0 accept(3, ..., ...) = 4
 31
 32   // send an iov of 18 elements: just becomes a linear skb
 33   +0 sendmsg(4, {msg_name(...)=...,
 34		  msg_iov(18)=[{..., 1}, {..., 1}, {..., 1}, {..., 1},
 35			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 36			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 37			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 38			       {..., 1}, {..., 1}],
 39		  msg_flags=0}, 0) = 18
 40
 41   +0 > P. 1:19(18) ack 1
 42   +0 < . 1:1(0) ack 19 win 257
 43
 44   // send a zerocopy iov of 18 elements:
 45   +1 sendmsg(4, {msg_name(...)=...,
 46		  msg_iov(18)=[{..., 1}, {..., 1}, {..., 1}, {..., 1},
 47			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 48			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 49			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 50			       {..., 1}, {..., 1}],
 51		  msg_flags=0}, MSG_ZEROCOPY) = 18
 52
 53   // verify that it is split in one skb of 17 frags + 1 of 1 frag
 54   // verify that both have the PSH bit set
 55   +0 > P. 19:36(17) ack 1
 56   +0 < . 1:1(0) ack 36 win 257
 57
 58   +0 > P. 36:37(1) ack 1
 59   +0 < . 1:1(0) ack 37 win 257
 60
 61   +1 recvmsg(4, {msg_name(...)=...,
 62                  msg_iov(1)=[{...,0}],
 63                  msg_flags=MSG_ERRQUEUE,
 64                  msg_control=[
 65                        {cmsg_level=CMSG_LEVEL_IP,
 66                         cmsg_type=CMSG_TYPE_RECVERR,
 67                         cmsg_data={ee_errno=0,
 68                                    ee_origin=SO_EE_ORIGIN_ZEROCOPY,
 69                                    ee_type=0,
 70                                    ee_code=SO_EE_CODE_ZEROCOPY_COPIED,
 71                                    ee_info=0,
 72                                    ee_data=0}}
 73                   ]}, MSG_ERRQUEUE) = 0
 74
 75   // send a zerocopy iov of 64 elements:
 76   +0 sendmsg(4, {msg_name(...)=...,
 77                  msg_iov(64)=[{..., 1}, {..., 1}, {..., 1}, {..., 1},
 78			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 79			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 80			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 81			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 82			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 83			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 84			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 85			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 86			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 87			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 88			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 89			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 90			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 91			       {..., 1}, {..., 1}, {..., 1}, {..., 1},
 92			       {..., 1}, {..., 1}, {..., 1}, {..., 1}],
 93                  msg_flags=0}, MSG_ZEROCOPY) = 64
 94
 95   // verify that it is split in skbs with 17 frags
 96   +0 > P. 37:54(17) ack 1
 97   +0 < . 1:1(0) ack 54 win 257
 98
 99   +0 > P. 54:71(17) ack 1
100   +0 < . 1:1(0) ack 71 win 257
101
102   +0 > P. 71:88(17) ack 1
103   +0 < . 1:1(0) ack 88 win 257
104
105   +0 > P. 88:101(13) ack 1
106   +0 < . 1:1(0) ack 101 win 257
107
108   +1 recvmsg(4, {msg_name(...)=...,
109                  msg_iov(1)=[{...,0}],
110                  msg_flags=MSG_ERRQUEUE,
111                  msg_control=[
112                        {cmsg_level=CMSG_LEVEL_IP,
113                         cmsg_type=CMSG_TYPE_RECVERR,
114                         cmsg_data={ee_errno=0,
115                                    ee_origin=SO_EE_ORIGIN_ZEROCOPY,
116                                    ee_type=0,
117                                    ee_code=SO_EE_CODE_ZEROCOPY_COPIED,
118                                    ee_info=1,
119                                    ee_data=1}}
120                   ]}, MSG_ERRQUEUE) = 0