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Diffstat (limited to 'net/core/ieee8021q_helpers.c')
| -rw-r--r-- | net/core/ieee8021q_helpers.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/net/core/ieee8021q_helpers.c b/net/core/ieee8021q_helpers.c new file mode 100644 index 000000000000..759a9b9f3f89 --- /dev/null +++ b/net/core/ieee8021q_helpers.c @@ -0,0 +1,242 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2024 Pengutronix, Oleksij Rempel <kernel@pengutronix.de> + +#include <linux/array_size.h> +#include <linux/printk.h> +#include <linux/types.h> +#include <net/dscp.h> +#include <net/ieee8021q.h> + +/* The following arrays map Traffic Types (TT) to traffic classes (TC) for + * different number of queues as shown in the example provided by + * IEEE 802.1Q-2022 in Annex I "I.3 Traffic type to traffic class mapping" and + * Table I-1 "Traffic type to traffic class mapping". + */ +static const u8 ieee8021q_8queue_tt_tc_map[] = { + [IEEE8021Q_TT_BK] = 0, + [IEEE8021Q_TT_BE] = 1, + [IEEE8021Q_TT_EE] = 2, + [IEEE8021Q_TT_CA] = 3, + [IEEE8021Q_TT_VI] = 4, + [IEEE8021Q_TT_VO] = 5, + [IEEE8021Q_TT_IC] = 6, + [IEEE8021Q_TT_NC] = 7, +}; + +static const u8 ieee8021q_7queue_tt_tc_map[] = { + [IEEE8021Q_TT_BK] = 0, + [IEEE8021Q_TT_BE] = 1, + [IEEE8021Q_TT_EE] = 2, + [IEEE8021Q_TT_CA] = 3, + [IEEE8021Q_TT_VI] = 4, [IEEE8021Q_TT_VO] = 4, + [IEEE8021Q_TT_IC] = 5, + [IEEE8021Q_TT_NC] = 6, +}; + +static const u8 ieee8021q_6queue_tt_tc_map[] = { + [IEEE8021Q_TT_BK] = 0, + [IEEE8021Q_TT_BE] = 1, + [IEEE8021Q_TT_EE] = 2, [IEEE8021Q_TT_CA] = 2, + [IEEE8021Q_TT_VI] = 3, [IEEE8021Q_TT_VO] = 3, + [IEEE8021Q_TT_IC] = 4, + [IEEE8021Q_TT_NC] = 5, +}; + +static const u8 ieee8021q_5queue_tt_tc_map[] = { + [IEEE8021Q_TT_BK] = 0, [IEEE8021Q_TT_BE] = 0, + [IEEE8021Q_TT_EE] = 1, [IEEE8021Q_TT_CA] = 1, + [IEEE8021Q_TT_VI] = 2, [IEEE8021Q_TT_VO] = 2, + [IEEE8021Q_TT_IC] = 3, + [IEEE8021Q_TT_NC] = 4, +}; + +static const u8 ieee8021q_4queue_tt_tc_map[] = { + [IEEE8021Q_TT_BK] = 0, [IEEE8021Q_TT_BE] = 0, + [IEEE8021Q_TT_EE] = 1, [IEEE8021Q_TT_CA] = 1, + [IEEE8021Q_TT_VI] = 2, [IEEE8021Q_TT_VO] = 2, + [IEEE8021Q_TT_IC] = 3, [IEEE8021Q_TT_NC] = 3, +}; + +static const u8 ieee8021q_3queue_tt_tc_map[] = { + [IEEE8021Q_TT_BK] = 0, [IEEE8021Q_TT_BE] = 0, + [IEEE8021Q_TT_EE] = 0, [IEEE8021Q_TT_CA] = 0, + [IEEE8021Q_TT_VI] = 1, [IEEE8021Q_TT_VO] = 1, + [IEEE8021Q_TT_IC] = 2, [IEEE8021Q_TT_NC] = 2, +}; + +static const u8 ieee8021q_2queue_tt_tc_map[] = { + [IEEE8021Q_TT_BK] = 0, [IEEE8021Q_TT_BE] = 0, + [IEEE8021Q_TT_EE] = 0, [IEEE8021Q_TT_CA] = 0, + [IEEE8021Q_TT_VI] = 1, [IEEE8021Q_TT_VO] = 1, + [IEEE8021Q_TT_IC] = 1, [IEEE8021Q_TT_NC] = 1, +}; + +static const u8 ieee8021q_1queue_tt_tc_map[] = { + [IEEE8021Q_TT_BK] = 0, [IEEE8021Q_TT_BE] = 0, + [IEEE8021Q_TT_EE] = 0, [IEEE8021Q_TT_CA] = 0, + [IEEE8021Q_TT_VI] = 0, [IEEE8021Q_TT_VO] = 0, + [IEEE8021Q_TT_IC] = 0, [IEEE8021Q_TT_NC] = 0, +}; + +/** + * ieee8021q_tt_to_tc - Map IEEE 802.1Q Traffic Type to Traffic Class + * @tt: IEEE 802.1Q Traffic Type + * @num_queues: Number of queues + * + * This function maps an IEEE 802.1Q Traffic Type to a Traffic Class (TC) based + * on the number of queues configured on the NIC. The mapping is based on the + * example provided by IEEE 802.1Q-2022 in Annex I "I.3 Traffic type to traffic + * class mapping" and Table I-1 "Traffic type to traffic class mapping". + * + * Return: Traffic Class corresponding to the given Traffic Type or negative + * value in case of error. + */ +int ieee8021q_tt_to_tc(enum ieee8021q_traffic_type tt, unsigned int num_queues) +{ + if (tt < 0 || tt >= IEEE8021Q_TT_MAX) { + pr_err("Requested Traffic Type (%d) is out of range (%d)\n", tt, + IEEE8021Q_TT_MAX); + return -EINVAL; + } + + switch (num_queues) { + case 8: + compiletime_assert(ARRAY_SIZE(ieee8021q_8queue_tt_tc_map) != + IEEE8021Q_TT_MAX - 1, + "ieee8021q_8queue_tt_tc_map != max - 1"); + return ieee8021q_8queue_tt_tc_map[tt]; + case 7: + compiletime_assert(ARRAY_SIZE(ieee8021q_7queue_tt_tc_map) != + IEEE8021Q_TT_MAX - 1, + "ieee8021q_7queue_tt_tc_map != max - 1"); + + return ieee8021q_7queue_tt_tc_map[tt]; + case 6: + compiletime_assert(ARRAY_SIZE(ieee8021q_6queue_tt_tc_map) != + IEEE8021Q_TT_MAX - 1, + "ieee8021q_6queue_tt_tc_map != max - 1"); + + return ieee8021q_6queue_tt_tc_map[tt]; + case 5: + compiletime_assert(ARRAY_SIZE(ieee8021q_5queue_tt_tc_map) != + IEEE8021Q_TT_MAX - 1, + "ieee8021q_5queue_tt_tc_map != max - 1"); + + return ieee8021q_5queue_tt_tc_map[tt]; + case 4: + compiletime_assert(ARRAY_SIZE(ieee8021q_4queue_tt_tc_map) != + IEEE8021Q_TT_MAX - 1, + "ieee8021q_4queue_tt_tc_map != max - 1"); + + return ieee8021q_4queue_tt_tc_map[tt]; + case 3: + compiletime_assert(ARRAY_SIZE(ieee8021q_3queue_tt_tc_map) != + IEEE8021Q_TT_MAX - 1, + "ieee8021q_3queue_tt_tc_map != max - 1"); + + return ieee8021q_3queue_tt_tc_map[tt]; + case 2: + compiletime_assert(ARRAY_SIZE(ieee8021q_2queue_tt_tc_map) != + IEEE8021Q_TT_MAX - 1, + "ieee8021q_2queue_tt_tc_map != max - 1"); + + return ieee8021q_2queue_tt_tc_map[tt]; + case 1: + compiletime_assert(ARRAY_SIZE(ieee8021q_1queue_tt_tc_map) != + IEEE8021Q_TT_MAX - 1, + "ieee8021q_1queue_tt_tc_map != max - 1"); + + return ieee8021q_1queue_tt_tc_map[tt]; + } + + pr_err("Invalid number of queues %d\n", num_queues); + + return -EINVAL; +} +EXPORT_SYMBOL_GPL(ieee8021q_tt_to_tc); + +/** + * ietf_dscp_to_ieee8021q_tt - Map IETF DSCP to IEEE 802.1Q Traffic Type + * @dscp: IETF DSCP value + * + * This function maps an IETF DSCP value to an IEEE 802.1Q Traffic Type (TT). + * Since there is no corresponding mapping between DSCP and IEEE 802.1Q Traffic + * Type, this function is inspired by the RFC8325 documentation which describe + * the mapping between DSCP and 802.11 User Priority (UP) values. + * + * Return: IEEE 802.1Q Traffic Type corresponding to the given DSCP value + */ +int ietf_dscp_to_ieee8021q_tt(u8 dscp) +{ + switch (dscp) { + case DSCP_CS0: + /* Comment from RFC8325: + * [RFC4594], Section 4.8, recommends High-Throughput Data be marked + * AF1x (that is, AF11, AF12, and AF13, according to the rules defined + * in [RFC2475]). + * + * By default (as described in Section 2.3), High-Throughput Data will + * map to UP 1 and, thus, to the Background Access Category (AC_BK), + * which is contrary to the intent expressed in [RFC4594]. + + * Unfortunately, there really is no corresponding fit for the High- + * Throughput Data service class within the constrained 4 Access + * Category [IEEE.802.11-2016] model. If the High-Throughput Data + * service class is assigned to the Best Effort Access Category (AC_BE), + * then it would contend with Low-Latency Data (while [RFC4594] + * recommends a distinction in servicing between these service classes) + * as well as with the default service class; alternatively, if it is + * assigned to the Background Access Category (AC_BK), then it would + * receive a less-then-best-effort service and contend with Low-Priority + * Data (as discussed in Section 4.2.10). + * + * As such, since there is no directly corresponding fit for the High- + * Throughout Data service class within the [IEEE.802.11-2016] model, it + * is generally RECOMMENDED to map High-Throughput Data to UP 0, thereby + * admitting it to the Best Effort Access Category (AC_BE). + * + * Note: The above text is from RFC8325 which is describing the mapping + * between DSCP and 802.11 User Priority (UP) values. The mapping + * between UP and IEEE 802.1Q Traffic Type is not defined in the RFC but + * the 802.11 AC_BK and AC_BE are closely related to the IEEE 802.1Q + * Traffic Types BE and BK. + */ + case DSCP_AF11: + case DSCP_AF12: + case DSCP_AF13: + return IEEE8021Q_TT_BE; + /* Comment from RFC8325: + * RFC3662 and RFC4594 both recommend Low-Priority Data be marked + * with DSCP CS1. The Low-Priority Data service class loosely + * corresponds to the [IEEE.802.11-2016] Background Access Category + */ + case DSCP_CS1: + return IEEE8021Q_TT_BK; + case DSCP_CS2: + case DSCP_AF21: + case DSCP_AF22: + case DSCP_AF23: + return IEEE8021Q_TT_EE; + case DSCP_CS3: + case DSCP_AF31: + case DSCP_AF32: + case DSCP_AF33: + return IEEE8021Q_TT_CA; + case DSCP_CS4: + case DSCP_AF41: + case DSCP_AF42: + case DSCP_AF43: + return IEEE8021Q_TT_VI; + case DSCP_CS5: + case DSCP_EF: + case DSCP_VOICE_ADMIT: + return IEEE8021Q_TT_VO; + case DSCP_CS6: + return IEEE8021Q_TT_IC; + case DSCP_CS7: + return IEEE8021Q_TT_NC; + } + + return SIMPLE_IETF_DSCP_TO_IEEE8021Q_TT(dscp); +} +EXPORT_SYMBOL_GPL(ietf_dscp_to_ieee8021q_tt); |