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`./defaults.sh` 11 12 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 13 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 14 +0 setsockopt(3, SOL_SOCKET, SO_ZEROCOPY, [1], 4) = 0 15 16 // Each pinned zerocopy page is fully accounted to skb->truesize. 17 // This test generates a worst case packet with each frag storing 18 // one byte, but increasing truesize with a page (64KB on PPC). 19 +0 setsockopt(3, SOL_SOCKET, SO_SNDBUF, [2000000], 4) = 0 20 21 +0 bind(3, ..., ...) = 0 22 +0 listen(3, 1) = 0 23 24 +0 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7> 25 +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8> 26 +0 < . 1:1(0) ack 1 win 257 27 28 +0 accept(3, ..., ...) = 4 29 30 // send an iov of 18 elements: just becomes a linear skb 31 +0 sendmsg(4, {msg_name(...)=..., 32 msg_iov(18)=[{..., 1}, {..., 1}, {..., 1}, {..., 1}, 33 {..., 1}, {..., 1}, {..., 1}, {..., 1}, 34 {..., 1}, {..., 1}, {..., 1}, {..., 1}, 35 {..., 1}, {..., 1}, {..., 1}, {..., 1}, 36 {..., 1}, {..., 1}], 37 msg_flags=0}, 0) = 18 38 39 +0 > P. 1:19(18) ack 1 40 +0 < . 1:1(0) ack 19 win 257 41 42 // send a zerocopy iov of 18 elements: 43 +1 sendmsg(4, {msg_name(...)=..., 44 msg_iov(18)=[{..., 1}, {..., 1}, {..., 1}, {..., 1}, 45 {..., 1}, {..., 1}, {..., 1}, {..., 1}, 46 {..., 1}, {..., 1}, {..., 1}, {..., 1}, 47 {..., 1}, {..., 1}, {..., 1}, {..., 1}, 48 {..., 1}, {..., 1}], 49 msg_flags=0}, MSG_ZEROCOPY) = 18 50 51 // verify that it is split in one skb of 17 frags + 1 of 1 frag 52 // verify that both have the PSH bit set 53 +0 > P. 19:36(17) ack 1 54 +0 < . 1:1(0) ack 36 win 257 55 56 +0 > P. 36:37(1) ack 1 57 +0 < . 1:1(0) ack 37 win 257 58 59 +1 recvmsg(4, {msg_name(...)=..., 60 msg_iov(1)=[{...,0}], 61 msg_flags=MSG_ERRQUEUE, 62 msg_control=[ 63 {cmsg_level=CMSG_LEVEL_IP, 64 cmsg_type=CMSG_TYPE_RECVERR, 65 cmsg_data={ee_errno=0, 66 ee_origin=SO_EE_ORIGIN_ZEROCOPY, 67 ee_type=0, 68 ee_code=SO_EE_CODE_ZEROCOPY_COPIED, 69 ee_info=0, 70 ee_data=0}} 71 ]}, MSG_ERRQUEUE) = 0 72 73 // send a zerocopy iov of 64 elements: 74 +0 sendmsg(4, {msg_name(...)=..., 75 msg_iov(64)=[{..., 1}, {..., 1}, {..., 1}, {..., 1}, 76 {..., 1}, {..., 1}, {..., 1}, {..., 1}, 77 {..., 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 msg_flags=0}, MSG_ZEROCOPY) = 64 92 93 // verify that it is split in skbs with 17 frags 94 +0 > P. 37:54(17) ack 1 95 +0 < . 1:1(0) ack 54 win 257 96 97 +0 > P. 54:71(17) ack 1 98 +0 < . 1:1(0) ack 71 win 257 99 100 +0 > P. 71:88(17) ack 1 101 +0 < . 1:1(0) ack 88 win 257 102 103 +0 > P. 88:101(13) ack 1 104 +0 < . 1:1(0) ack 101 win 257 105 106 +1 recvmsg(4, {msg_name(...)=..., 107 msg_iov(1)=[{...,0}], 108 msg_flags=MSG_ERRQUEUE, 109 msg_control=[ 110 {cmsg_level=CMSG_LEVEL_IP, 111 cmsg_type=CMSG_TYPE_RECVERR, 112 cmsg_data={ee_errno=0, 113 ee_origin=SO_EE_ORIGIN_ZEROCOPY, 114 ee_type=0, 115 ee_code=SO_EE_CODE_ZEROCOPY_COPIED, 116 ee_info=1, 117 ee_data=1}} 118 ]}, MSG_ERRQUEUE) = 0 119