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Diffstat (limited to 'include/net/dropreason-qdisc.h')
| -rw-r--r-- | include/net/dropreason-qdisc.h | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/include/net/dropreason-qdisc.h b/include/net/dropreason-qdisc.h new file mode 100644 index 000000000000..fb151cd31751 --- /dev/null +++ b/include/net/dropreason-qdisc.h @@ -0,0 +1,114 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#ifndef _LINUX_DROPREASON_QDISC_H +#define _LINUX_DROPREASON_QDISC_H +#include <net/dropreason.h> + +#define DEFINE_QDISC_DROP_REASON(FN, FNe) \ + FN(UNSPEC) \ + FN(GENERIC) \ + FN(OVERLIMIT) \ + FN(CONGESTED) \ + FN(MAXFLOWS) \ + FN(FLOOD_PROTECTION) \ + FN(BAND_LIMIT) \ + FN(HORIZON_LIMIT) \ + FN(FLOW_LIMIT) \ + FN(L4S_STEP_NON_ECN) \ + FNe(MAX) + +#undef FN +#undef FNe +#define FN(reason) QDISC_DROP_##reason, +#define FNe(reason) QDISC_DROP_##reason + +/** + * enum qdisc_drop_reason - reason why a qdisc dropped a packet + * + * Qdisc-specific drop reasons for packet drops that occur within the + * traffic control (TC) queueing discipline layer. These reasons provide + * detailed diagnostics about why packets were dropped by various qdisc + * algorithms, enabling fine-grained monitoring and troubleshooting of + * queue behavior. + */ +enum qdisc_drop_reason { + /** + * @QDISC_DROP_UNSPEC: unspecified/invalid qdisc drop reason. + * Value 0 serves as analogous to SKB_NOT_DROPPED_YET for enum skb_drop_reason. + * Used for catching zero-initialized drop_reason fields. + */ + QDISC_DROP_UNSPEC = 0, + /** + * @__QDISC_DROP_REASON: subsystem base value for qdisc drop reasons + */ + __QDISC_DROP_REASON = SKB_DROP_REASON_SUBSYS_QDISC << + SKB_DROP_REASON_SUBSYS_SHIFT, + /** + * @QDISC_DROP_GENERIC: generic/default qdisc drop, used when no + * more specific reason applies + */ + QDISC_DROP_GENERIC, + /** + * @QDISC_DROP_OVERLIMIT: packet dropped because the qdisc queue + * length exceeded its configured limit (sch->limit). This typically + * indicates the queue is full and cannot accept more packets. + */ + QDISC_DROP_OVERLIMIT, + /** + * @QDISC_DROP_CONGESTED: packet dropped due to active congestion + * control algorithms (e.g., CoDel, PIE, RED) detecting network + * congestion. The qdisc proactively dropped the packet to signal + * congestion to the sender and prevent bufferbloat. + */ + QDISC_DROP_CONGESTED, + /** + * @QDISC_DROP_MAXFLOWS: packet dropped because the qdisc's flow + * tracking table is full and no free slots are available to allocate + * for a new flow. This indicates flow table exhaustion in flow-based + * qdiscs that maintain per-flow state (e.g., SFQ). + */ + QDISC_DROP_MAXFLOWS, + /** + * @QDISC_DROP_FLOOD_PROTECTION: packet dropped by flood protection + * mechanism detecting unresponsive flows (potential DoS/flood). + * Used by qdiscs implementing probabilistic drop algorithms like + * BLUE (e.g., CAKE's Cobalt AQM). + */ + QDISC_DROP_FLOOD_PROTECTION, + /** + * @QDISC_DROP_BAND_LIMIT: packet dropped because the priority band's + * limit was reached. Used by qdiscs with priority bands that have + * per-band packet limits (e.g., FQ). + */ + QDISC_DROP_BAND_LIMIT, + /** + * @QDISC_DROP_HORIZON_LIMIT: packet dropped because its timestamp + * is too far in the future (beyond the configured horizon). + * Used by qdiscs with time-based scheduling (e.g., FQ). + */ + QDISC_DROP_HORIZON_LIMIT, + /** + * @QDISC_DROP_FLOW_LIMIT: packet dropped because an individual flow + * exceeded its per-flow packet/depth limit. Used by FQ and SFQ qdiscs + * to enforce per-flow fairness and prevent a single flow from + * monopolizing queue resources. + */ + QDISC_DROP_FLOW_LIMIT, + /** + * @QDISC_DROP_L4S_STEP_NON_ECN: DualPI2 qdisc dropped a non-ECN-capable + * packet because the L4S queue delay exceeded the step threshold. + * Since the packet cannot be ECN-marked, it must be dropped to signal + * congestion. See RFC 9332 for the DualQ Coupled AQM step mechanism. + */ + QDISC_DROP_L4S_STEP_NON_ECN, + /** + * @QDISC_DROP_MAX: the maximum of qdisc drop reasons, which + * shouldn't be used as a real 'reason' - only for tracing code gen + */ + QDISC_DROP_MAX, +}; + +#undef FN +#undef FNe + +#endif |