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
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