diff options
Diffstat (limited to 'test/packetdrill/tests/linux/pmtu_discovery/pmtud-1pkt-1460-to-1160.pkt')
| -rw-r--r-- | test/packetdrill/tests/linux/pmtu_discovery/pmtud-1pkt-1460-to-1160.pkt | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/test/packetdrill/tests/linux/pmtu_discovery/pmtud-1pkt-1460-to-1160.pkt b/test/packetdrill/tests/linux/pmtu_discovery/pmtud-1pkt-1460-to-1160.pkt new file mode 100644 index 0000000..9776f10 --- /dev/null +++ b/test/packetdrill/tests/linux/pmtu_discovery/pmtud-1pkt-1460-to-1160.pkt @@ -0,0 +1,36 @@ +// Test Path MTU discovery, RFC 1191. +// This is a simple case, with one packet to send. +// In this variant, we get an ICMP "unreachable frag_needed mtu 1200" +// message and because the TCP sequence number is valid, TCP +// immediately retransmits our first outstanding packet +// with a smaller MSS based on the MTU from the ICMP message. + +// Establish a connection. +0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0.000 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0.000 bind(3, ..., ...) = 0 +0.000 listen(3, 1) = 0 + +0.100 < S 0:0(0) win 32792 <mss 1460,nop,wscale 7> +0.100 > S. 0:0(0) ack 1 <mss 1460,nop,wscale 6> +0.200 < . 1:1(0) ack 1 win 257 +0.200 accept(3, ..., ...) = 4 + +// Send 1 data segment. +0.200 write(4, ..., 1460) = 1460 +0.200 > P. 1:1461(1460) ack 1 + +// ICMP says that segment was too big. +0.250 < [1:1461(1460)] icmp unreachable frag_needed mtu 1200 +// TCP picks a packet size using the MTU from the message, and retransmits. +0.250 > . 1:1161(1160) ack 1 +0.250 > P. 1161:1461(300) ack 1 + +// Receiver ACKs all data. +0.350 < . 1:1(0) ack 1461 win 257 + +// Clean up. +1.300 close(4) = 0 +1.300 > F. 1461:1461(0) ack 1 +1.400 < F. 1:1(0) ack 1462 win 257 +1.400 > . 1462:1462(0) ack 2 |