| // SPDX-License-Identifier: GPL-2.0 |
| // tcp_MAX_SKB_FRAGS test |
| // |
| // Verify that sending an iovec of tcp_MAX_SKB_FRAGS + 1 elements will |
| // 1) fit in a single packet without zerocopy |
| // 2) spill over into a second packet with zerocopy, |
| // because each iovec element becomes a frag |
| // 3) the PSH bit is set on an skb when it runs out of fragments |
| |
| `./defaults.sh` |
| |
| 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 |
| +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 |
| +0 setsockopt(3, SOL_SOCKET, SO_ZEROCOPY, [1], 4) = 0 |
| |
| // Each pinned zerocopy page is fully accounted to skb->truesize. |
| // This test generates a worst case packet with each frag storing |
| // one byte, but increasing truesize with a page (64KB on PPC). |
| +0 setsockopt(3, SOL_SOCKET, SO_SNDBUF, [2000000], 4) = 0 |
| |
| +0 bind(3, ..., ...) = 0 |
| +0 listen(3, 1) = 0 |
| |
| +0 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7> |
| +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8> |
| +0 < . 1:1(0) ack 1 win 257 |
| |
| +0 accept(3, ..., ...) = 4 |
| |
| // send an iov of 18 elements: just becomes a linear skb |
| +0 sendmsg(4, {msg_name(...)=..., |
| msg_iov(18)=[{..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}], |
| msg_flags=0}, 0) = 18 |
| |
| +0 > P. 1:19(18) ack 1 |
| +0 < . 1:1(0) ack 19 win 257 |
| |
| // send a zerocopy iov of 18 elements: |
| +1 sendmsg(4, {msg_name(...)=..., |
| msg_iov(18)=[{..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}], |
| msg_flags=0}, MSG_ZEROCOPY) = 18 |
| |
| // verify that it is split in one skb of 17 frags + 1 of 1 frag |
| // verify that both have the PSH bit set |
| +0 > P. 19:36(17) ack 1 |
| +0 < . 1:1(0) ack 36 win 257 |
| |
| +0 > P. 36:37(1) ack 1 |
| +0 < . 1:1(0) ack 37 win 257 |
| |
| +1 recvmsg(4, {msg_name(...)=..., |
| msg_iov(1)=[{...,0}], |
| msg_flags=MSG_ERRQUEUE, |
| msg_control=[ |
| {cmsg_level=CMSG_LEVEL_IP, |
| cmsg_type=CMSG_TYPE_RECVERR, |
| cmsg_data={ee_errno=0, |
| ee_origin=SO_EE_ORIGIN_ZEROCOPY, |
| ee_type=0, |
| ee_code=SO_EE_CODE_ZEROCOPY_COPIED, |
| ee_info=0, |
| ee_data=0}} |
| ]}, MSG_ERRQUEUE) = 0 |
| |
| // send a zerocopy iov of 64 elements: |
| +0 sendmsg(4, {msg_name(...)=..., |
| msg_iov(64)=[{..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}, |
| {..., 1}, {..., 1}, {..., 1}, {..., 1}], |
| msg_flags=0}, MSG_ZEROCOPY) = 64 |
| |
| // verify that it is split in skbs with 17 frags |
| +0 > P. 37:54(17) ack 1 |
| +0 < . 1:1(0) ack 54 win 257 |
| |
| +0 > P. 54:71(17) ack 1 |
| +0 < . 1:1(0) ack 71 win 257 |
| |
| +0 > P. 71:88(17) ack 1 |
| +0 < . 1:1(0) ack 88 win 257 |
| |
| +0 > P. 88:101(13) ack 1 |
| +0 < . 1:1(0) ack 101 win 257 |
| |
| +1 recvmsg(4, {msg_name(...)=..., |
| msg_iov(1)=[{...,0}], |
| msg_flags=MSG_ERRQUEUE, |
| msg_control=[ |
| {cmsg_level=CMSG_LEVEL_IP, |
| cmsg_type=CMSG_TYPE_RECVERR, |
| cmsg_data={ee_errno=0, |
| ee_origin=SO_EE_ORIGIN_ZEROCOPY, |
| ee_type=0, |
| ee_code=SO_EE_CODE_ZEROCOPY_COPIED, |
| ee_info=1, |
| ee_data=1}} |
| ]}, MSG_ERRQUEUE) = 0 |
