1 | /* |
2 | * Copyright (c) 2000-2021 Apple Inc. All rights reserved. |
3 | * |
4 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ |
5 | * |
6 | * This file contains Original Code and/or Modifications of Original Code |
7 | * as defined in and that are subject to the Apple Public Source License |
8 | * Version 2.0 (the 'License'). You may not use this file except in |
9 | * compliance with the License. The rights granted to you under the License |
10 | * may not be used to create, or enable the creation or redistribution of, |
11 | * unlawful or unlicensed copies of an Apple operating system, or to |
12 | * circumvent, violate, or enable the circumvention or violation of, any |
13 | * terms of an Apple operating system software license agreement. |
14 | * |
15 | * Please obtain a copy of the License at |
16 | * http://www.opensource.apple.com/apsl/ and read it before using this file. |
17 | * |
18 | * The Original Code and all software distributed under the License are |
19 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
20 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
21 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
22 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
23 | * Please see the License for the specific language governing rights and |
24 | * limitations under the License. |
25 | * |
26 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ |
27 | */ |
28 | |
29 | #include "tcp_includes.h" |
30 | |
31 | #include <netinet/tcp_sysctls.h> |
32 | #include <netinet/tcp_var.h> |
33 | |
34 | #include <sys/sysctl.h> |
35 | |
36 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, cubic_tcp_friendliness, CTLFLAG_RW | CTLFLAG_LOCKED, |
37 | int, tcp_cubic_tcp_friendliness, 0, "Enable TCP friendliness" ); |
38 | |
39 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, cubic_fast_convergence, CTLFLAG_RW | CTLFLAG_LOCKED, |
40 | int, tcp_cubic_fast_convergence, 0, "Enable fast convergence" ); |
41 | |
42 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, cubic_use_minrtt, CTLFLAG_RW | CTLFLAG_LOCKED, |
43 | int, tcp_cubic_use_minrtt, 0, "use a min of 5 sec rtt" ); |
44 | |
45 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, cubic_minor_fixes, CTLFLAG_RW | CTLFLAG_LOCKED, |
46 | int, tcp_cubic_minor_fixes, 1, "Minor fixes to TCP Cubic" ); |
47 | |
48 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, cubic_rfc_compliant, CTLFLAG_RW | CTLFLAG_LOCKED, |
49 | int, tcp_cubic_rfc_compliant, 1, "RFC Compliance for TCP Cubic" ); |
50 | |
51 | /* Target queuing delay in milliseconds. This includes the processing |
52 | * and scheduling delay on both of the end-hosts. A LEDBAT sender tries |
53 | * to keep queuing delay below this limit. When the queuing delay |
54 | * goes above this limit, a LEDBAT sender will start reducing the |
55 | * congestion window. |
56 | * |
57 | * The LEDBAT draft says that target queue delay MUST be 100 ms for |
58 | * inter-operability. |
59 | * As we are enabling LEDBAT++ by default, we are updating the target |
60 | * queuing delay to 60ms as recommended by the draft. |
61 | */ |
62 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, bg_target_qdelay, CTLFLAG_RW | CTLFLAG_LOCKED, |
63 | int, target_qdelay, 40, "Target queuing delay" ); |
64 | |
65 | /* Allowed increase and tether are used to place an upper bound on |
66 | * congestion window based on the amount of data that is outstanding. |
67 | * This will limit the congestion window when the amount of data in |
68 | * flight is little because the application is writing to the socket |
69 | * intermittently and is preventing the connection from becoming idle . |
70 | * |
71 | * max_allowed_cwnd = allowed_increase + (tether * flight_size) |
72 | * cwnd = min(cwnd, max_allowed_cwnd) |
73 | * |
74 | * 'Allowed_increase' parameter is set to 8. If the flight size is zero, then |
75 | * we want the congestion window to be at least 8 packets to reduce the |
76 | * delay induced by delayed ack. This helps when the receiver is acking |
77 | * more than 2 packets at a time (stretching acks for better performance). |
78 | * |
79 | * 'Tether' is also set to 2. We do not want this to limit the growth of cwnd |
80 | * during slow-start. |
81 | */ |
82 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, bg_allowed_increase, CTLFLAG_RW | CTLFLAG_LOCKED, |
83 | int, tcp_ledbat_allowed_increase, 8, |
84 | "Additive constant used to calculate max allowed congestion window" ); |
85 | |
86 | /* Left shift for cwnd to get tether value of 2 */ |
87 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, bg_tether_shift, CTLFLAG_RW | CTLFLAG_LOCKED, |
88 | int, tcp_ledbat_tether_shift, 1, "Tether shift for max allowed congestion window" ); |
89 | |
90 | /* Start with an initial window of 2. This will help to get more accurate |
91 | * minimum RTT measurement in the beginning. It will help to probe |
92 | * the path slowly and will not add to the existing delay if the path is |
93 | * already congested. Using 2 packets will reduce the delay induced by delayed-ack. |
94 | */ |
95 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, bg_ss_fltsz, CTLFLAG_RW | CTLFLAG_LOCKED, |
96 | uint32_t, bg_ss_fltsz, 2, "Initial congestion window for background transport" ); |
97 | |
98 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, ledbat_plus_plus, CTLFLAG_RW | CTLFLAG_LOCKED, |
99 | int, tcp_ledbat_plus_plus, 1, "Use LEDBAT++" ); |
100 | |
101 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, rledbat, CTLFLAG_RW | CTLFLAG_LOCKED, |
102 | int, tcp_rledbat, 1, "Use Receive LEDBAT" ); |
103 | |
104 | int tcp_cc_debug; |
105 | SYSCTL_INT(_net_inet_tcp, OID_AUTO, cc_debug, CTLFLAG_RW | CTLFLAG_LOCKED, |
106 | &tcp_cc_debug, 0, "Enable debug data collection" ); |
107 | |
108 | extern struct tcp_cc_algo tcp_cc_newreno; |
109 | SYSCTL_INT(_net_inet_tcp, OID_AUTO, newreno_sockets, |
110 | CTLFLAG_RD | CTLFLAG_LOCKED, &tcp_cc_newreno.num_sockets, |
111 | 0, "Number of sockets using newreno" ); |
112 | |
113 | extern struct tcp_cc_algo tcp_cc_ledbat; |
114 | SYSCTL_INT(_net_inet_tcp, OID_AUTO, background_sockets, |
115 | CTLFLAG_RD | CTLFLAG_LOCKED, &tcp_cc_ledbat.num_sockets, |
116 | 0, "Number of sockets using background transport" ); |
117 | |
118 | #if (DEVELOPMENT || DEBUG) |
119 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, use_ledbat, |
120 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_use_ledbat, 0, |
121 | "Use TCP LEDBAT for testing" ); |
122 | #else |
123 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, use_ledbat, |
124 | CTLFLAG_RD | CTLFLAG_LOCKED, int, tcp_use_ledbat, 0, |
125 | "Use TCP LEDBAT for testing" ); |
126 | #endif /* (DEVELOPMENT || DEBUG) */ |
127 | |
128 | extern struct tcp_cc_algo tcp_cc_cubic; |
129 | SYSCTL_INT(_net_inet_tcp, OID_AUTO, cubic_sockets, |
130 | CTLFLAG_RD | CTLFLAG_LOCKED, &tcp_cc_cubic.num_sockets, |
131 | 0, "Number of sockets using cubic" ); |
132 | |
133 | SYSCTL_SKMEM_TCP_INT(OID_AUTO, use_newreno, |
134 | CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_use_newreno, 0, |
135 | "Use TCP NewReno by default" ); |
136 | |