ENUM SKB_DROP_REASON(9)

💅 enum skb_drop_reason(9) 💅

Okay bestie, welcome to the Kernel API Manual page for enum skb_drop_reason(9) — the official roster of reasons an skb gets dropped. It’s literally the receipts for packets that didn’t make it, and we’re going through every single one. 💖

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✨ NAME ✨

enum skb_drop_reason — the reasons of skb drops. No cap, that’s the whole name section. 💀

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🌈 SYNOPSIS 🌈

Here’s the full enum lineup, verbatim, no edits, no crumbs left behind:

       enum skb_drop_reason {
           SKB_NOT_DROPPED_YET ,
           SKB_CONSUMED ,
           SKB_DROP_REASON_NOT_SPECIFIED ,
           SKB_DROP_REASON_NO_SOCKET ,
           SKB_DROP_REASON_SOCKET_CLOSE ,
           SKB_DROP_REASON_SOCKET_FILTER ,
           SKB_DROP_REASON_SOCKET_RCVBUFF ,
           SKB_DROP_REASON_UNIX_DISCONNECT ,
           SKB_DROP_REASON_UNIX_SKIP_OOB ,
           SKB_DROP_REASON_PKT_TOO_SMALL ,
           SKB_DROP_REASON_TCP_CSUM ,
           SKB_DROP_REASON_UDP_CSUM ,
           SKB_DROP_REASON_NETFILTER_DROP ,
           SKB_DROP_REASON_OTHERHOST ,
           SKB_DROP_REASON_IP_CSUM ,
           SKB_DROP_REASON_IP_INHDR ,
           SKB_DROP_REASON_IP_RPFILTER ,
           SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST ,
           SKB_DROP_REASON_XFRM_POLICY ,
           SKB_DROP_REASON_IP_NOPROTO ,
           SKB_DROP_REASON_PROTO_MEM ,
           SKB_DROP_REASON_TCP_AUTH_HDR ,
           SKB_DROP_REASON_TCP_MD5NOTFOUND ,
           SKB_DROP_REASON_TCP_MD5UNEXPECTED ,
           SKB_DROP_REASON_TCP_MD5FAILURE ,
           SKB_DROP_REASON_TCP_AONOTFOUND ,
           SKB_DROP_REASON_TCP_AOUNEXPECTED ,
           SKB_DROP_REASON_TCP_AOKEYNOTFOUND ,
           SKB_DROP_REASON_TCP_AOFAILURE ,
           SKB_DROP_REASON_SOCKET_BACKLOG ,
           SKB_DROP_REASON_TCP_FLAGS ,
           SKB_DROP_REASON_TCP_ABORT_ON_DATA ,
           SKB_DROP_REASON_TCP_ZEROWINDOW ,
           SKB_DROP_REASON_TCP_OLD_DATA ,
           SKB_DROP_REASON_TCP_OVERWINDOW ,
           SKB_DROP_REASON_TCP_OFOMERGE ,
           SKB_DROP_REASON_TCP_RFC7323_PAWS ,
           SKB_DROP_REASON_TCP_RFC7323_PAWS_ACK ,
           SKB_DROP_REASON_TCP_RFC7323_TW_PAWS ,
           SKB_DROP_REASON_TCP_RFC7323_TSECR ,
           SKB_DROP_REASON_TCP_LISTEN_OVERFLOW ,
           SKB_DROP_REASON_TCP_OLD_SEQUENCE ,
           SKB_DROP_REASON_TCP_INVALID_SEQUENCE ,
           SKB_DROP_REASON_TCP_INVALID_END_SEQUENCE ,
           SKB_DROP_REASON_TCP_INVALID_ACK_SEQUENCE ,
           SKB_DROP_REASON_TCP_RESET ,
           SKB_DROP_REASON_TCP_INVALID_SYN ,
           SKB_DROP_REASON_TCP_CLOSE ,
           SKB_DROP_REASON_TCP_FASTOPEN ,
           SKB_DROP_REASON_TCP_OLD_ACK ,
           SKB_DROP_REASON_TCP_TOO_OLD_ACK ,
           SKB_DROP_REASON_TCP_ACK_UNSENT_DATA ,
           SKB_DROP_REASON_TCP_OFO_QUEUE_PRUNE ,
           SKB_DROP_REASON_TCP_OFO_DROP ,
           SKB_DROP_REASON_IP_OUTNOROUTES ,
           SKB_DROP_REASON_BPF_CGROUP_EGRESS ,
           SKB_DROP_REASON_IPV6DISABLED ,
           SKB_DROP_REASON_NEIGH_CREATEFAIL ,
           SKB_DROP_REASON_NEIGH_FAILED ,
           SKB_DROP_REASON_NEIGH_QUEUEFULL ,
           SKB_DROP_REASON_NEIGH_DEAD ,
           SKB_DROP_REASON_NEIGH_HH_FILLFAIL ,
           SKB_DROP_REASON_TC_EGRESS ,
           SKB_DROP_REASON_SECURITY_HOOK ,
           SKB_DROP_REASON_QDISC_DROP ,
           SKB_DROP_REASON_QDISC_BURST_DROP ,
           SKB_DROP_REASON_CPU_BACKLOG ,
           SKB_DROP_REASON_MACVLAN_BROADCAST_BACKLOG ,
           SKB_DROP_REASON_IPVLAN_MULTICAST_BACKLOG ,
           SKB_DROP_REASON_XDP ,
           SKB_DROP_REASON_TC_INGRESS ,
           SKB_DROP_REASON_UNHANDLED_PROTO ,
           SKB_DROP_REASON_SKB_CSUM ,
           SKB_DROP_REASON_SKB_GSO_SEG ,
           SKB_DROP_REASON_SKB_BAD_GSO ,
           SKB_DROP_REASON_SKB_UCOPY_FAULT ,
           SKB_DROP_REASON_DEV_HDR ,
           SKB_DROP_REASON_DEV_READY ,
           SKB_DROP_REASON_FULL_RING ,
           SKB_DROP_REASON_NOMEM ,
           SKB_DROP_REASON_HDR_TRUNC ,
           SKB_DROP_REASON_TAP_FILTER ,
           SKB_DROP_REASON_TAP_TXFILTER ,
           SKB_DROP_REASON_ICMP_CSUM ,
           SKB_DROP_REASON_INVALID_PROTO ,
           SKB_DROP_REASON_IP_INADDRERRORS ,
           SKB_DROP_REASON_IP_INNOROUTES ,
           SKB_DROP_REASON_IP_LOCAL_SOURCE ,
           SKB_DROP_REASON_IP_INVALID_SOURCE ,
           SKB_DROP_REASON_IP_LOCALNET ,
           SKB_DROP_REASON_IP_INVALID_DEST ,
           SKB_DROP_REASON_PKT_TOO_BIG ,
           SKB_DROP_REASON_DUP_FRAG ,
           SKB_DROP_REASON_FRAG_REASM_TIMEOUT ,
           SKB_DROP_REASON_FRAG_TOO_FAR ,
           SKB_DROP_REASON_TCP_MINTTL ,
           SKB_DROP_REASON_IPV6_BAD_EXTHDR ,
           SKB_DROP_REASON_IPV6_TOO_MANY_EXTHDRS ,
           SKB_DROP_REASON_IPV6_NDISC_FRAG ,
           SKB_DROP_REASON_IPV6_NDISC_HOP_LIMIT ,
           SKB_DROP_REASON_IPV6_NDISC_BAD_CODE ,
           SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS ,
           SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST ,
           SKB_DROP_REASON_QUEUE_PURGE ,
           SKB_DROP_REASON_TC_COOKIE_ERROR ,
           SKB_DROP_REASON_PACKET_SOCK_ERROR ,
           SKB_DROP_REASON_TC_CHAIN_NOTFOUND ,
           SKB_DROP_REASON_TC_RECLASSIFY_LOOP ,
           SKB_DROP_REASON_VXLAN_INVALID_HDR ,
           SKB_DROP_REASON_VXLAN_VNI_NOT_FOUND ,
           SKB_DROP_REASON_MAC_INVALID_SOURCE ,
           SKB_DROP_REASON_VXLAN_ENTRY_EXISTS ,
           SKB_DROP_REASON_NO_TX_TARGET ,
           SKB_DROP_REASON_IP_TUNNEL_ECN ,
           SKB_DROP_REASON_TUNNEL_TXINFO ,
           SKB_DROP_REASON_LOCAL_MAC ,
           SKB_DROP_REASON_ARP_PVLAN_DISABLE ,
           SKB_DROP_REASON_MAC_IEEE_MAC_CONTROL ,
           SKB_DROP_REASON_BRIDGE_INGRESS_STP_STATE ,
           SKB_DROP_REASON_CAN_RX_INVALID_FRAME ,
           SKB_DROP_REASON_CANFD_RX_INVALID_FRAME ,
           SKB_DROP_REASON_CANXL_RX_INVALID_FRAME ,
           SKB_DROP_REASON_PFMEMALLOC ,
           SKB_DROP_REASON_PSP_INPUT ,
           SKB_DROP_REASON_PSP_OUTPUT ,
           SKB_DROP_REASON_RECURSION_LIMIT ,
           SKB_DROP_REASON_MAX ,
           SKB_DROP_REASON_SUBSYS_MASK

       };

---

🎀 Constants 🎀

These are the constants, bestie — each one a little label for why the packet got sent to the shadow realm. 🦋

• SKB_NOT_DROPPED_YET — skb is not dropped yet, used for the no-drop case. It’s giving “still alive and thriving” energy. ✨
• SKB_CONSUMED — packet has been consumed. Gone, eaten, no crumbs. 💅
• SKB_DROP_REASON_NOT_SPECIFIED — drop reason is not specified. We literally don’t know why. 😭
• SKB_DROP_REASON_NO_SOCKET — no valid socket that can be used. The reason could be one of three cases:
  1. no established/listening socket found during lookup process
  2. no valid request socket during 3WHS process
  3. no valid child socket during 3WHS process
• SKB_DROP_REASON_SOCKET_CLOSE — socket is closed.
• SKB_DROP_REASON_SOCKET_FILTER — dropped by socket filter.
• SKB_DROP_REASON_SOCKET_RCVBUFF — socket receive buff is full.
• SKB_DROP_REASON_UNIX_DISCONNECT — recv queue is purged when SOCK_DGRAM or SOCK_SEQPACKET socket re-connects to another socket or notices during send that the peer has been closed.
• SKB_DROP_REASON_UNIX_SKIP_OOB — Out-Of-Band data is skipped by recv without MSG_OOB so dropped.
• SKB_DROP_REASON_PKT_TOO_SMALL — packet size is too small.
• SKB_DROP_REASON_TCP_CSUM — TCP checksum error.
• SKB_DROP_REASON_UDP_CSUM — UDP checksum error.
• SKB_DROP_REASON_NETFILTER_DROP — dropped by netfilter.
• SKB_DROP_REASON_OTHERHOST — packet don’t belong to current host (interface is in promisc mode).
• SKB_DROP_REASON_IP_CSUM — IP checksum error.
• SKB_DROP_REASON_IP_INHDR — there is something wrong with IP header (see IPSTATS_MIB_INHDRERRORS).
• SKB_DROP_REASON_IP_RPFILTER — IP rpfilter validate failed. See the document for rp_filter in ip-sysctl.rst for more information.
• SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST — destination address of L2 is multicast, but L3 is unicast.
• SKB_DROP_REASON_XFRM_POLICY — xfrm policy check failed.
• SKB_DROP_REASON_IP_NOPROTO — no support for IP protocol.
• SKB_DROP_REASON_PROTO_MEM — proto memory limitation, such as udp packet drop out of udp_memory_allocated.
• SKB_DROP_REASON_TCP_AUTH_HDR — TCP-MD5 or TCP-AO hashes are met twice or set incorrectly.
• SKB_DROP_REASON_TCP_MD5NOTFOUND — no MD5 hash and one expected, corresponding to LINUX_MIB_TCPMD5NOTFOUND.
• SKB_DROP_REASON_TCP_MD5UNEXPECTED — MD5 hash and we’re not expecting one, corresponding to LINUX_MIB_TCPMD5UNEXPECTED.
• SKB_DROP_REASON_TCP_MD5FAILURE — MD5 hash and its wrong, corresponding to LINUX_MIB_TCPMD5FAILURE.
• SKB_DROP_REASON_TCP_AONOTFOUND — no TCP-AO hash and one was expected, corresponding to LINUX_MIB_TCPAOREQUIRED.
• SKB_DROP_REASON_TCP_AOUNEXPECTED — TCP-AO hash is present and it was not expected, corresponding to LINUX_MIB_TCPAOKEYNOTFOUND.
• SKB_DROP_REASON_TCP_AOKEYNOTFOUND — TCP-AO key is unknown, corresponding to LINUX_MIB_TCPAOKEYNOTFOUND.
• SKB_DROP_REASON_TCP_AOFAILURE — TCP-AO hash is wrong, corresponding to LINUX_MIB_TCPAOBAD.
• SKB_DROP_REASON_SOCKET_BACKLOG — failed to add skb to socket backlog (see LINUX_MIB_TCPBACKLOGDROP).
• SKB_DROP_REASON_TCP_FLAGS — TCP flags invalid.
• SKB_DROP_REASON_TCP_ABORT_ON_DATA — abort on data, corresponding to LINUX_MIB_TCPABORTONDATA.
• SKB_DROP_REASON_TCP_ZEROWINDOW — TCP receive window size is zero, see LINUX_MIB_TCPZEROWINDOWDROP.
• SKB_DROP_REASON_TCP_OLD_DATA — the TCP data received is already received before (spurious retrans may happened), see LINUX_MIB_DELAYEDACKLOST.
• SKB_DROP_REASON_TCP_OVERWINDOW — the TCP data is out of window, the seq of the first byte exceed the right edges of receive window.
• SKB_DROP_REASON_TCP_OFOMERGE — the data of skb is already in the ofo queue, corresponding to LINUX_MIB_TCPOFOMERGE.
• SKB_DROP_REASON_TCP_RFC7323_PAWS — PAWS check, corresponding to LINUX_MIB_PAWSESTABREJECTED, LINUX_MIB_PAWSACTIVEREJECTED.
• SKB_DROP_REASON_TCP_RFC7323_PAWS_ACK — PAWS check, old ACK packet. Corresponds to LINUX_MIB_PAWS_OLD_ACK.
• SKB_DROP_REASON_TCP_RFC7323_TW_PAWS — PAWS check, socket is in TIME_WAIT state. Corresponds to LINUX_MIB_PAWS_TW_REJECTED.
• SKB_DROP_REASON_TCP_RFC7323_TSECR — PAWS check, invalid TSEcr. Corresponds to LINUX_MIB_TSECRREJECTED.
• SKB_DROP_REASON_TCP_LISTEN_OVERFLOW — listener queue full.
• SKB_DROP_REASON_TCP_OLD_SEQUENCE — Old SEQ field (duplicate packet).
• SKB_DROP_REASON_TCP_INVALID_SEQUENCE — Not acceptable SEQ field.
• SKB_DROP_REASON_TCP_INVALID_END_SEQUENCE — Not acceptable END_SEQ field. Corresponds to LINUX_MIB_BEYOND_WINDOW.
• SKB_DROP_REASON_TCP_INVALID_ACK_SEQUENCE — Not acceptable ACK SEQ field because ack sequence is not in the window between snd_una and snd_nxt.
• SKB_DROP_REASON_TCP_RESET — Invalid RST packet.
• SKB_DROP_REASON_TCP_INVALID_SYN — Incoming packet has unexpected SYN flag.
• SKB_DROP_REASON_TCP_CLOSE — TCP socket in CLOSE state.
• SKB_DROP_REASON_TCP_FASTOPEN — dropped by FASTOPEN request socket ✨
• SKB_DROP_REASON_TCP_OLD_ACK — TCP ACK is old, but in window
• SKB_DROP_REASON_TCP_TOO_OLD_ACK — TCP ACK is too old 😭
• SKB_DROP_REASON_TCP_ACK_UNSENT_DATA — TCP ACK for data we haven't sent yet (bold of it tbh)
• SKB_DROP_REASON_TCP_OFO_QUEUE_PRUNE — pruned from TCP OFO queue
• SKB_DROP_REASON_TCP_OFO_DROP — data already in receive queue
• SKB_DROP_REASON_IP_OUTNOROUTES — route lookup failed 🫠
• SKB_DROP_REASON_BPF_CGROUP_EGRESS — dropped by BPF_PROG_TYPE_CGROUP_SKB eBPF program
• SKB_DROP_REASON_IPV6DISABLED — IPv6 is disabled on the device
• SKB_DROP_REASON_NEIGH_CREATEFAIL — failed to create neigh entry
• SKB_DROP_REASON_NEIGH_FAILED — neigh entry in failed state
• SKB_DROP_REASON_NEIGH_QUEUEFULL — arp_queue for neigh entry is full
• SKB_DROP_REASON_NEIGH_DEAD — neigh entry is dead 💀
• SKB_DROP_REASON_NEIGH_HH_FILLFAIL — failed to fill the device hard header
• SKB_DROP_REASON_TC_EGRESS — dropped in TC egress HOOK
• SKB_DROP_REASON_SECURITY_HOOK — dropped due to security HOOK
• SKB_DROP_REASON_QDISC_DROP — dropped by qdisc during enqueue or dequeue. More specific drop reasons are available via the qdisc:qdisc_drop tracepoint, which also provides qdisc handle and name for identifying the source 👑
• SKB_DROP_REASON_QDISC_BURST_DROP — dropped when net.core.qdisc_max_burst limit is hit.
• SKB_DROP_REASON_CPU_BACKLOG — failed to enqueue the skb to the per CPU backlog queue. This can be caused by backlog queue full (see netdev_max_backlog in net.rst) or RPS flow limit
• SKB_DROP_REASON_MACVLAN_BROADCAST_BACKLOG — failed to enqueue the skb to macvlan broadcast queue.
• SKB_DROP_REASON_IPVLAN_MULTICAST_BACKLOG — failed to enqueue the skb to ipvlan multicast queue.
• SKB_DROP_REASON_XDP — dropped by XDP in input path
• SKB_DROP_REASON_TC_INGRESS — dropped in TC ingress HOOK
• SKB_DROP_REASON_UNHANDLED_PROTO — protocol not implemented or not supported
• SKB_DROP_REASON_SKB_CSUM — sk_buff checksum computation error
• SKB_DROP_REASON_SKB_GSO_SEG — gso segmentation error
• SKB_DROP_REASON_SKB_BAD_GSO — malicious gso packet. 🚨
• SKB_DROP_REASON_SKB_UCOPY_FAULT — failed to copy data from user space, e.g., via zerocopy_sg_from_iter or skb_orphan_frags_rx
• SKB_DROP_REASON_DEV_HDR — device driver specific header/metadata is invalid
• SKB_DROP_REASON_DEV_READY — the device is not ready to xmit/recv due to any of its data structure that is not up/ready/initialized, e.g., the IFF_UP is not set, or driver specific tun->tfiles[txq] is not initialized
• SKB_DROP_REASON_FULL_RING — ring buffer is full
• SKB_DROP_REASON_NOMEM — error due to OOM
• SKB_DROP_REASON_HDR_TRUNC — failed to trunc/extract the header from networking data, e.g., failed to pull the protocol header from frags via pskb_may_pull
• SKB_DROP_REASON_TAP_FILTER — dropped by (ebpf) filter directly attached to tun/tap, e.g., via TUNSETFILTEREBPF
• SKB_DROP_REASON_TAP_TXFILTER — dropped by tx filter implemented at tun/tap, e.g., check_filter
• SKB_DROP_REASON_ICMP_CSUM — ICMP checksum error
• SKB_DROP_REASON_INVALID_PROTO — the packet doesn't follow RFC 2211, such as a broadcasts ICMP_TIMESTAMP
• SKB_DROP_REASON_IP_INADDRERRORS — host unreachable, corresponding to IPSTATS_MIB_INADDRERRORS
• SKB_DROP_REASON_IP_INNOROUTES — network unreachable, corresponding to IPSTATS_MIB_INADDRERRORS
• SKB_DROP_REASON_IP_LOCAL_SOURCE — the source ip is local
• SKB_DROP_REASON_IP_INVALID_SOURCE — the source ip is invalid:
  1. source ip is multicast or limited broadcast
  2. source ip is zero and not IGMP
• SKB_DROP_REASON_IP_LOCALNET — source or dest ip is local net
• SKB_DROP_REASON_IP_INVALID_DEST — the dest ip is invalid:
  1. dest ip is 0
• SKB_DROP_REASON_PKT_TOO_BIG — packet size is too big (maybe exceed the MTU)
• SKB_DROP_REASON_DUP_FRAG — duplicate fragment
• SKB_DROP_REASON_FRAG_REASM_TIMEOUT — fragment reassembly timeout ⏰
• SKB_DROP_REASON_FRAG_TOO_FAR — ipv4 fragment too far. (/proc/sys/net/ipv4/ipfrag_max_dist)
• SKB_DROP_REASON_TCP_MINTTL — ipv4 ttl or ipv6 hoplimit below the threshold (IP_MINTTL or IPV6_MINHOPCOUNT).
• SKB_DROP_REASON_IPV6_BAD_EXTHDR — Bad IPv6 extension header.
• SKB_DROP_REASON_IPV6_TOO_MANY_EXTHDRS — Number of IPv6 extension headers in the packet exceeds IP6_MAX_EXT_HDRS_CNT.
• SKB_DROP_REASON_IPV6_NDISC_FRAG — invalid frag (suppress_frag_ndisc).
• SKB_DROP_REASON_IPV6_NDISC_HOP_LIMIT — invalid hop limit.
• SKB_DROP_REASON_IPV6_NDISC_BAD_CODE — invalid NDISC icmp6 code.
• SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS — invalid NDISC options.
• SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST — NEIGHBOUR SOLICITATION for another host.
• SKB_DROP_REASON_QUEUE_PURGE — bulk free.
• SKB_DROP_REASON_TC_COOKIE_ERROR — An error occurred whilst processing a tc ext cookie.
• SKB_DROP_REASON_PACKET_SOCK_ERROR — generic packet socket errors after its filter matches an incoming packet.
• SKB_DROP_REASON_TC_CHAIN_NOTFOUND — tc chain lookup failed. 😔
• SKB_DROP_REASON_TC_RECLASSIFY_LOOP — tc exceeded max reclassify loop iterations.
• SKB_DROP_REASON_VXLAN_INVALID_HDR — VXLAN header is invalid. E.g.:
  1. reserved fields are not zero
  2. "I" flag is not set
• SKB_DROP_REASON_VXLAN_VNI_NOT_FOUND — no VXLAN device found for VNI
• SKB_DROP_REASON_MAC_INVALID_SOURCE — source mac is invalid
• SKB_DROP_REASON_VXLAN_ENTRY_EXISTS — trying to migrate a static entry or an entry pointing to a nexthop.
• SKB_DROP_REASON_NO_TX_TARGET — no target found for xmit
• SKB_DROP_REASON_IP_TUNNEL_ECN — skb is dropped according to RFC 6040 4.2, see __INET_ECN_decapsulate for detail.
• SKB_DROP_REASON_TUNNEL_TXINFO — packet without necessary metadata reached a device which is in "external" mode.
• SKB_DROP_REASON_LOCAL_MAC — the source MAC address is equal to the MAC address of the local netdev.
• SKB_DROP_REASON_ARP_PVLAN_DISABLE — packet which is not IP is forwarded to the in_dev, and the proxy_arp_pvlan is not enabled.
• SKB_DROP_REASON_MAC_IEEE_MAC_CONTROL — the destination MAC address is an IEEE MAC Control address.
• SKB_DROP_REASON_BRIDGE_INGRESS_STP_STATE — the STP state of the ingress bridge port does not allow frames to be forwarded.
• SKB_DROP_REASON_CAN_RX_INVALID_FRAME — received non conform CAN frame (or device is unable to receive CAN frames)
• SKB_DROP_REASON_CANFD_RX_INVALID_FRAME — received non conform CAN-FD frame (or device is unable to receive CAN frames)
• SKB_DROP_REASON_CANXL_RX_INVALID_FRAME — received non conform CAN-XL frame (or device is unable to receive CAN frames)
• SKB_DROP_REASON_PFMEMALLOC — packet allocated from memory reserve reached a path or socket not eligible for use of memory reserves
• SKB_DROP_REASON_PSP_INPUT — PSP input checks failed
• SKB_DROP_REASON_PSP_OUTPUT — PSP output checks failed
• SKB_DROP_REASON_RECURSION_LIMIT — Dead loop on virtual device. 🌀
• SKB_DROP_REASON_MAX — the maximum of core drop reasons, which shouldn't be used as a real 'reason' — only for tracing code gen. No cap, do not use it as an actual reason.
• SKB_DROP_REASON_SUBSYS_MASK — subsystem mask in drop reasons, see enum skb_drop_reason_subsys

---

🌸 Description 🌸

Okay so this whole enum is the reason of skb drop, which is used in kfree_skb_reason. That's the whole vibe — every time the kernel yeets a socket buffer, one of these tells you why. 🫶

---

🦋 SEE ALSO 🦋

Kernel file ./include/net/dropreason-core.h

---

And that's a wrap bestie, you made it to the end of the drop-reason lore 💖 This page came from the source path ./include/net, dated October 2026, and it's the enum skb_drop_reason(9) page — iconic, no notes 👑✨🎀