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-rw-r--r--net/dccp/ackvec.c403
1 files changed, 0 insertions, 403 deletions
diff --git a/net/dccp/ackvec.c b/net/dccp/ackvec.c
deleted file mode 100644
index 1cba001bb4c8..000000000000
--- a/net/dccp/ackvec.c
+++ /dev/null
@@ -1,403 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * net/dccp/ackvec.c
- *
- * An implementation of Ack Vectors for the DCCP protocol
- * Copyright (c) 2007 University of Aberdeen, Scotland, UK
- * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
- */
-#include "dccp.h"
-#include <linux/kernel.h>
-#include <linux/slab.h>
-#include <linux/export.h>
-
-static struct kmem_cache *dccp_ackvec_slab;
-static struct kmem_cache *dccp_ackvec_record_slab;
-
-struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
-{
- struct dccp_ackvec *av = kmem_cache_zalloc(dccp_ackvec_slab, priority);
-
- if (av != NULL) {
- av->av_buf_head = av->av_buf_tail = DCCPAV_MAX_ACKVEC_LEN - 1;
- INIT_LIST_HEAD(&av->av_records);
- }
- return av;
-}
-
-static void dccp_ackvec_purge_records(struct dccp_ackvec *av)
-{
- struct dccp_ackvec_record *cur, *next;
-
- list_for_each_entry_safe(cur, next, &av->av_records, avr_node)
- kmem_cache_free(dccp_ackvec_record_slab, cur);
- INIT_LIST_HEAD(&av->av_records);
-}
-
-void dccp_ackvec_free(struct dccp_ackvec *av)
-{
- if (likely(av != NULL)) {
- dccp_ackvec_purge_records(av);
- kmem_cache_free(dccp_ackvec_slab, av);
- }
-}
-
-/**
- * dccp_ackvec_update_records - Record information about sent Ack Vectors
- * @av: Ack Vector records to update
- * @seqno: Sequence number of the packet carrying the Ack Vector just sent
- * @nonce_sum: The sum of all buffer nonces contained in the Ack Vector
- */
-int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seqno, u8 nonce_sum)
-{
- struct dccp_ackvec_record *avr;
-
- avr = kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
- if (avr == NULL)
- return -ENOBUFS;
-
- avr->avr_ack_seqno = seqno;
- avr->avr_ack_ptr = av->av_buf_head;
- avr->avr_ack_ackno = av->av_buf_ackno;
- avr->avr_ack_nonce = nonce_sum;
- avr->avr_ack_runlen = dccp_ackvec_runlen(av->av_buf + av->av_buf_head);
- /*
- * When the buffer overflows, we keep no more than one record. This is
- * the simplest way of disambiguating sender-Acks dating from before the
- * overflow from sender-Acks which refer to after the overflow; a simple
- * solution is preferable here since we are handling an exception.
- */
- if (av->av_overflow)
- dccp_ackvec_purge_records(av);
- /*
- * Since GSS is incremented for each packet, the list is automatically
- * arranged in descending order of @ack_seqno.
- */
- list_add(&avr->avr_node, &av->av_records);
-
- dccp_pr_debug("Added Vector, ack_seqno=%llu, ack_ackno=%llu (rl=%u)\n",
- (unsigned long long)avr->avr_ack_seqno,
- (unsigned long long)avr->avr_ack_ackno,
- avr->avr_ack_runlen);
- return 0;
-}
-
-static struct dccp_ackvec_record *dccp_ackvec_lookup(struct list_head *av_list,
- const u64 ackno)
-{
- struct dccp_ackvec_record *avr;
- /*
- * Exploit that records are inserted in descending order of sequence
- * number, start with the oldest record first. If @ackno is `before'
- * the earliest ack_ackno, the packet is too old to be considered.
- */
- list_for_each_entry_reverse(avr, av_list, avr_node) {
- if (avr->avr_ack_seqno == ackno)
- return avr;
- if (before48(ackno, avr->avr_ack_seqno))
- break;
- }
- return NULL;
-}
-
-/*
- * Buffer index and length computation using modulo-buffersize arithmetic.
- * Note that, as pointers move from right to left, head is `before' tail.
- */
-static inline u16 __ackvec_idx_add(const u16 a, const u16 b)
-{
- return (a + b) % DCCPAV_MAX_ACKVEC_LEN;
-}
-
-static inline u16 __ackvec_idx_sub(const u16 a, const u16 b)
-{
- return __ackvec_idx_add(a, DCCPAV_MAX_ACKVEC_LEN - b);
-}
-
-u16 dccp_ackvec_buflen(const struct dccp_ackvec *av)
-{
- if (unlikely(av->av_overflow))
- return DCCPAV_MAX_ACKVEC_LEN;
- return __ackvec_idx_sub(av->av_buf_tail, av->av_buf_head);
-}
-
-/**
- * dccp_ackvec_update_old - Update previous state as per RFC 4340, 11.4.1
- * @av: non-empty buffer to update
- * @distance: negative or zero distance of @seqno from buf_ackno downward
- * @seqno: the (old) sequence number whose record is to be updated
- * @state: state in which packet carrying @seqno was received
- */
-static void dccp_ackvec_update_old(struct dccp_ackvec *av, s64 distance,
- u64 seqno, enum dccp_ackvec_states state)
-{
- u16 ptr = av->av_buf_head;
-
- BUG_ON(distance > 0);
- if (unlikely(dccp_ackvec_is_empty(av)))
- return;
-
- do {
- u8 runlen = dccp_ackvec_runlen(av->av_buf + ptr);
-
- if (distance + runlen >= 0) {
- /*
- * Only update the state if packet has not been received
- * yet. This is OK as per the second table in RFC 4340,
- * 11.4.1; i.e. here we are using the following table:
- * RECEIVED
- * 0 1 3
- * S +---+---+---+
- * T 0 | 0 | 0 | 0 |
- * O +---+---+---+
- * R 1 | 1 | 1 | 1 |
- * E +---+---+---+
- * D 3 | 0 | 1 | 3 |
- * +---+---+---+
- * The "Not Received" state was set by reserve_seats().
- */
- if (av->av_buf[ptr] == DCCPAV_NOT_RECEIVED)
- av->av_buf[ptr] = state;
- else
- dccp_pr_debug("Not changing %llu state to %u\n",
- (unsigned long long)seqno, state);
- break;
- }
-
- distance += runlen + 1;
- ptr = __ackvec_idx_add(ptr, 1);
-
- } while (ptr != av->av_buf_tail);
-}
-
-/* Mark @num entries after buf_head as "Not yet received". */
-static void dccp_ackvec_reserve_seats(struct dccp_ackvec *av, u16 num)
-{
- u16 start = __ackvec_idx_add(av->av_buf_head, 1),
- len = DCCPAV_MAX_ACKVEC_LEN - start;
-
- /* check for buffer wrap-around */
- if (num > len) {
- memset(av->av_buf + start, DCCPAV_NOT_RECEIVED, len);
- start = 0;
- num -= len;
- }
- if (num)
- memset(av->av_buf + start, DCCPAV_NOT_RECEIVED, num);
-}
-
-/**
- * dccp_ackvec_add_new - Record one or more new entries in Ack Vector buffer
- * @av: container of buffer to update (can be empty or non-empty)
- * @num_packets: number of packets to register (must be >= 1)
- * @seqno: sequence number of the first packet in @num_packets
- * @state: state in which packet carrying @seqno was received
- */
-static void dccp_ackvec_add_new(struct dccp_ackvec *av, u32 num_packets,
- u64 seqno, enum dccp_ackvec_states state)
-{
- u32 num_cells = num_packets;
-
- if (num_packets > DCCPAV_BURST_THRESH) {
- u32 lost_packets = num_packets - 1;
-
- DCCP_WARN("Warning: large burst loss (%u)\n", lost_packets);
- /*
- * We received 1 packet and have a loss of size "num_packets-1"
- * which we squeeze into num_cells-1 rather than reserving an
- * entire byte for each lost packet.
- * The reason is that the vector grows in O(burst_length); when
- * it grows too large there will no room left for the payload.
- * This is a trade-off: if a few packets out of the burst show
- * up later, their state will not be changed; it is simply too
- * costly to reshuffle/reallocate/copy the buffer each time.
- * Should such problems persist, we will need to switch to a
- * different underlying data structure.
- */
- for (num_packets = num_cells = 1; lost_packets; ++num_cells) {
- u8 len = min_t(u32, lost_packets, DCCPAV_MAX_RUNLEN);
-
- av->av_buf_head = __ackvec_idx_sub(av->av_buf_head, 1);
- av->av_buf[av->av_buf_head] = DCCPAV_NOT_RECEIVED | len;
-
- lost_packets -= len;
- }
- }
-
- if (num_cells + dccp_ackvec_buflen(av) >= DCCPAV_MAX_ACKVEC_LEN) {
- DCCP_CRIT("Ack Vector buffer overflow: dropping old entries");
- av->av_overflow = true;
- }
-
- av->av_buf_head = __ackvec_idx_sub(av->av_buf_head, num_packets);
- if (av->av_overflow)
- av->av_buf_tail = av->av_buf_head;
-
- av->av_buf[av->av_buf_head] = state;
- av->av_buf_ackno = seqno;
-
- if (num_packets > 1)
- dccp_ackvec_reserve_seats(av, num_packets - 1);
-}
-
-/**
- * dccp_ackvec_input - Register incoming packet in the buffer
- * @av: Ack Vector to register packet to
- * @skb: Packet to register
- */
-void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb)
-{
- u64 seqno = DCCP_SKB_CB(skb)->dccpd_seq;
- enum dccp_ackvec_states state = DCCPAV_RECEIVED;
-
- if (dccp_ackvec_is_empty(av)) {
- dccp_ackvec_add_new(av, 1, seqno, state);
- av->av_tail_ackno = seqno;
-
- } else {
- s64 num_packets = dccp_delta_seqno(av->av_buf_ackno, seqno);
- u8 *current_head = av->av_buf + av->av_buf_head;
-
- if (num_packets == 1 &&
- dccp_ackvec_state(current_head) == state &&
- dccp_ackvec_runlen(current_head) < DCCPAV_MAX_RUNLEN) {
-
- *current_head += 1;
- av->av_buf_ackno = seqno;
-
- } else if (num_packets > 0) {
- dccp_ackvec_add_new(av, num_packets, seqno, state);
- } else {
- dccp_ackvec_update_old(av, num_packets, seqno, state);
- }
- }
-}
-
-/**
- * dccp_ackvec_clear_state - Perform house-keeping / garbage-collection
- * @av: Ack Vector record to clean
- * @ackno: last Ack Vector which has been acknowledged
- *
- * This routine is called when the peer acknowledges the receipt of Ack Vectors
- * up to and including @ackno. While based on section A.3 of RFC 4340, here
- * are additional precautions to prevent corrupted buffer state. In particular,
- * we use tail_ackno to identify outdated records; it always marks the earliest
- * packet of group (2) in 11.4.2.
- */
-void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno)
-{
- struct dccp_ackvec_record *avr, *next;
- u8 runlen_now, eff_runlen;
- s64 delta;
-
- avr = dccp_ackvec_lookup(&av->av_records, ackno);
- if (avr == NULL)
- return;
- /*
- * Deal with outdated acknowledgments: this arises when e.g. there are
- * several old records and the acks from the peer come in slowly. In
- * that case we may still have records that pre-date tail_ackno.
- */
- delta = dccp_delta_seqno(av->av_tail_ackno, avr->avr_ack_ackno);
- if (delta < 0)
- goto free_records;
- /*
- * Deal with overlapping Ack Vectors: don't subtract more than the
- * number of packets between tail_ackno and ack_ackno.
- */
- eff_runlen = delta < avr->avr_ack_runlen ? delta : avr->avr_ack_runlen;
-
- runlen_now = dccp_ackvec_runlen(av->av_buf + avr->avr_ack_ptr);
- /*
- * The run length of Ack Vector cells does not decrease over time. If
- * the run length is the same as at the time the Ack Vector was sent, we
- * free the ack_ptr cell. That cell can however not be freed if the run
- * length has increased: in this case we need to move the tail pointer
- * backwards (towards higher indices), to its next-oldest neighbour.
- */
- if (runlen_now > eff_runlen) {
-
- av->av_buf[avr->avr_ack_ptr] -= eff_runlen + 1;
- av->av_buf_tail = __ackvec_idx_add(avr->avr_ack_ptr, 1);
-
- /* This move may not have cleared the overflow flag. */
- if (av->av_overflow)
- av->av_overflow = (av->av_buf_head == av->av_buf_tail);
- } else {
- av->av_buf_tail = avr->avr_ack_ptr;
- /*
- * We have made sure that avr points to a valid cell within the
- * buffer. This cell is either older than head, or equals head
- * (empty buffer): in both cases we no longer have any overflow.
- */
- av->av_overflow = 0;
- }
-
- /*
- * The peer has acknowledged up to and including ack_ackno. Hence the
- * first packet in group (2) of 11.4.2 is the successor of ack_ackno.
- */
- av->av_tail_ackno = ADD48(avr->avr_ack_ackno, 1);
-
-free_records:
- list_for_each_entry_safe_from(avr, next, &av->av_records, avr_node) {
- list_del(&avr->avr_node);
- kmem_cache_free(dccp_ackvec_record_slab, avr);
- }
-}
-
-/*
- * Routines to keep track of Ack Vectors received in an skb
- */
-int dccp_ackvec_parsed_add(struct list_head *head, u8 *vec, u8 len, u8 nonce)
-{
- struct dccp_ackvec_parsed *new = kmalloc(sizeof(*new), GFP_ATOMIC);
-
- if (new == NULL)
- return -ENOBUFS;
- new->vec = vec;
- new->len = len;
- new->nonce = nonce;
-
- list_add_tail(&new->node, head);
- return 0;
-}
-EXPORT_SYMBOL_GPL(dccp_ackvec_parsed_add);
-
-void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks)
-{
- struct dccp_ackvec_parsed *cur, *next;
-
- list_for_each_entry_safe(cur, next, parsed_chunks, node)
- kfree(cur);
- INIT_LIST_HEAD(parsed_chunks);
-}
-EXPORT_SYMBOL_GPL(dccp_ackvec_parsed_cleanup);
-
-int __init dccp_ackvec_init(void)
-{
- dccp_ackvec_slab = KMEM_CACHE(dccp_ackvec, SLAB_HWCACHE_ALIGN);
- if (dccp_ackvec_slab == NULL)
- goto out_err;
-
- dccp_ackvec_record_slab = KMEM_CACHE(dccp_ackvec_record, SLAB_HWCACHE_ALIGN);
- if (dccp_ackvec_record_slab == NULL)
- goto out_destroy_slab;
-
- return 0;
-
-out_destroy_slab:
- kmem_cache_destroy(dccp_ackvec_slab);
- dccp_ackvec_slab = NULL;
-out_err:
- DCCP_CRIT("Unable to create Ack Vector slab cache");
- return -ENOBUFS;
-}
-
-void dccp_ackvec_exit(void)
-{
- kmem_cache_destroy(dccp_ackvec_slab);
- dccp_ackvec_slab = NULL;
- kmem_cache_destroy(dccp_ackvec_record_slab);
- dccp_ackvec_record_slab = NULL;
-}
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