--- /dev/null
+/*
+ * net/dccp/ackvec.c
+ *
+ * An implementation of the DCCP protocol
+ * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License;
+ */
+
+#include "ackvec.h"
+#include "dccp.h"
+
+#include <linux/dccp.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+
+#include <net/sock.h>
+
+static kmem_cache_t *dccp_ackvec_slab;
+static kmem_cache_t *dccp_ackvec_record_slab;
+
+static struct dccp_ackvec_record *dccp_ackvec_record_new(void)
+{
+ struct dccp_ackvec_record *avr =
+ kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
+
+ if (avr != NULL)
+ INIT_LIST_HEAD(&avr->dccpavr_node);
+
+ return avr;
+}
+
+static void dccp_ackvec_record_delete(struct dccp_ackvec_record *avr)
+{
+ if (unlikely(avr == NULL))
+ return;
+ /* Check if deleting a linked record */
+ WARN_ON(!list_empty(&avr->dccpavr_node));
+ kmem_cache_free(dccp_ackvec_record_slab, avr);
+}
+
+static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
+ struct dccp_ackvec_record *avr)
+{
+ /*
+ * AVRs are sorted by seqno. Since we are sending them in order, we
+ * just add the AVR at the head of the list.
+ * -sorbo.
+ */
+ if (!list_empty(&av->dccpav_records)) {
+ const struct dccp_ackvec_record *head =
+ list_entry(av->dccpav_records.next,
+ struct dccp_ackvec_record,
+ dccpavr_node);
+ BUG_ON(before48(avr->dccpavr_ack_seqno,
+ head->dccpavr_ack_seqno));
+ }
+
+ list_add(&avr->dccpavr_node, &av->dccpav_records);
+}
+
+int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+#ifdef CONFIG_IP_DCCP_DEBUG
+ const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
+ "CLIENT tx: " : "server tx: ";
+#endif
+ struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
+ int len = av->dccpav_vec_len + 2;
+ struct timeval now;
+ u32 elapsed_time;
+ unsigned char *to, *from;
+ struct dccp_ackvec_record *avr;
+
+ if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
+ return -1;
+
+ dccp_timestamp(sk, &now);
+ elapsed_time = timeval_delta(&now, &av->dccpav_time) / 10;
+
+ if (elapsed_time != 0 &&
+ dccp_insert_option_elapsed_time(sk, skb, elapsed_time))
+ return -1;
+
+ avr = dccp_ackvec_record_new();
+ if (avr == NULL)
+ return -1;
+
+ DCCP_SKB_CB(skb)->dccpd_opt_len += len;
+
+ to = skb_push(skb, len);
+ *to++ = DCCPO_ACK_VECTOR_0;
+ *to++ = len;
+
+ len = av->dccpav_vec_len;
+ from = av->dccpav_buf + av->dccpav_buf_head;
+
+ /* Check if buf_head wraps */
+ if ((int)av->dccpav_buf_head + len > DCCP_MAX_ACKVEC_LEN) {
+ const u32 tailsize = DCCP_MAX_ACKVEC_LEN - av->dccpav_buf_head;
+
+ memcpy(to, from, tailsize);
+ to += tailsize;
+ len -= tailsize;
+ from = av->dccpav_buf;
+ }
+
+ memcpy(to, from, len);
+ /*
+ * From draft-ietf-dccp-spec-11.txt:
+ *
+ * For each acknowledgement it sends, the HC-Receiver will add an
+ * acknowledgement record. ack_seqno will equal the HC-Receiver
+ * sequence number it used for the ack packet; ack_ptr will equal
+ * buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
+ * equal buf_nonce.
+ */
+ avr->dccpavr_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
+ avr->dccpavr_ack_ptr = av->dccpav_buf_head;
+ avr->dccpavr_ack_ackno = av->dccpav_buf_ackno;
+ avr->dccpavr_ack_nonce = av->dccpav_buf_nonce;
+ avr->dccpavr_sent_len = av->dccpav_vec_len;
+
+ dccp_ackvec_insert_avr(av, avr);
+
+ dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, "
+ "ack_ackno=%llu\n",
+ debug_prefix, avr->dccpavr_sent_len,
+ (unsigned long long)avr->dccpavr_ack_seqno,
+ (unsigned long long)avr->dccpavr_ack_ackno);
+ return 0;
+}
+
+struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
+{
+ struct dccp_ackvec *av = kmem_cache_alloc(dccp_ackvec_slab, priority);
+
+ if (av != NULL) {
+ av->dccpav_buf_head =
+ av->dccpav_buf_tail = DCCP_MAX_ACKVEC_LEN - 1;
+ av->dccpav_buf_ackno = DCCP_MAX_SEQNO + 1;
+ av->dccpav_buf_nonce = av->dccpav_buf_nonce = 0;
+ av->dccpav_ack_ptr = 0;
+ av->dccpav_time.tv_sec = 0;
+ av->dccpav_time.tv_usec = 0;
+ av->dccpav_sent_len = av->dccpav_vec_len = 0;
+ INIT_LIST_HEAD(&av->dccpav_records);
+ }
+
+ return av;
+}
+
+void dccp_ackvec_free(struct dccp_ackvec *av)
+{
+ if (unlikely(av == NULL))
+ return;
+
+ if (!list_empty(&av->dccpav_records)) {
+ struct dccp_ackvec_record *avr, *next;
+
+ list_for_each_entry_safe(avr, next, &av->dccpav_records,
+ dccpavr_node) {
+ list_del_init(&avr->dccpavr_node);
+ dccp_ackvec_record_delete(avr);
+ }
+ }
+
+ kmem_cache_free(dccp_ackvec_slab, av);
+}
+
+static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av,
+ const u8 index)
+{
+ return av->dccpav_buf[index] & DCCP_ACKVEC_STATE_MASK;
+}
+
+static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av,
+ const u8 index)
+{
+ return av->dccpav_buf[index] & DCCP_ACKVEC_LEN_MASK;
+}
+
+/*
+ * If several packets are missing, the HC-Receiver may prefer to enter multiple
+ * bytes with run length 0, rather than a single byte with a larger run length;
+ * this simplifies table updates if one of the missing packets arrives.
+ */
+static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
+ const unsigned int packets,
+ const unsigned char state)
+{
+ unsigned int gap;
+ long new_head;
+
+ if (av->dccpav_vec_len + packets > DCCP_MAX_ACKVEC_LEN)
+ return -ENOBUFS;
+
+ gap = packets - 1;
+ new_head = av->dccpav_buf_head - packets;
+
+ if (new_head < 0) {
+ if (gap > 0) {
+ memset(av->dccpav_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED,
+ gap + new_head + 1);
+ gap = -new_head;
+ }
+ new_head += DCCP_MAX_ACKVEC_LEN;
+ }
+
+ av->dccpav_buf_head = new_head;
+
+ if (gap > 0)
+ memset(av->dccpav_buf + av->dccpav_buf_head + 1,
+ DCCP_ACKVEC_STATE_NOT_RECEIVED, gap);
+
+ av->dccpav_buf[av->dccpav_buf_head] = state;
+ av->dccpav_vec_len += packets;
+ return 0;
+}
+
+/*
+ * Implements the draft-ietf-dccp-spec-11.txt Appendix A
+ */
+int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
+ const u64 ackno, const u8 state)
+{
+ /*
+ * Check at the right places if the buffer is full, if it is, tell the
+ * caller to start dropping packets till the HC-Sender acks our ACK
+ * vectors, when we will free up space in dccpav_buf.
+ *
+ * We may well decide to do buffer compression, etc, but for now lets
+ * just drop.
+ *
+ * From Appendix A:
+ *
+ * Of course, the circular buffer may overflow, either when the
+ * HC-Sender is sending data at a very high rate, when the
+ * HC-Receiver's acknowledgements are not reaching the HC-Sender,
+ * or when the HC-Sender is forgetting to acknowledge those acks
+ * (so the HC-Receiver is unable to clean up old state). In this
+ * case, the HC-Receiver should either compress the buffer (by
+ * increasing run lengths when possible), transfer its state to
+ * a larger buffer, or, as a last resort, drop all received
+ * packets, without processing them whatsoever, until its buffer
+ * shrinks again.
+ */
+
+ /* See if this is the first ackno being inserted */
+ if (av->dccpav_vec_len == 0) {
+ av->dccpav_buf[av->dccpav_buf_head] = state;
+ av->dccpav_vec_len = 1;
+ } else if (after48(ackno, av->dccpav_buf_ackno)) {
+ const u64 delta = dccp_delta_seqno(av->dccpav_buf_ackno,
+ ackno);
+
+ /*
+ * Look if the state of this packet is the same as the
+ * previous ackno and if so if we can bump the head len.
+ */
+ if (delta == 1 &&
+ dccp_ackvec_state(av, av->dccpav_buf_head) == state &&
+ (dccp_ackvec_len(av, av->dccpav_buf_head) <
+ DCCP_ACKVEC_LEN_MASK))
+ av->dccpav_buf[av->dccpav_buf_head]++;
+ else if (dccp_ackvec_set_buf_head_state(av, delta, state))
+ return -ENOBUFS;
+ } else {
+ /*
+ * A.1.2. Old Packets
+ *
+ * When a packet with Sequence Number S arrives, and
+ * S <= buf_ackno, the HC-Receiver will scan the table
+ * for the byte corresponding to S. (Indexing structures
+ * could reduce the complexity of this scan.)
+ */
+ u64 delta = dccp_delta_seqno(ackno, av->dccpav_buf_ackno);
+ u8 index = av->dccpav_buf_head;
+
+ while (1) {
+ const u8 len = dccp_ackvec_len(av, index);
+ const u8 state = dccp_ackvec_state(av, index);
+ /*
+ * valid packets not yet in dccpav_buf have a reserved
+ * entry, with a len equal to 0.
+ */
+ if (state == DCCP_ACKVEC_STATE_NOT_RECEIVED &&
+ len == 0 && delta == 0) { /* Found our
+ reserved seat! */
+ dccp_pr_debug("Found %llu reserved seat!\n",
+ (unsigned long long)ackno);
+ av->dccpav_buf[index] = state;
+ goto out;
+ }
+ /* len == 0 means one packet */
+ if (delta < len + 1)
+ goto out_duplicate;
+
+ delta -= len + 1;
+ if (++index == DCCP_MAX_ACKVEC_LEN)
+ index = 0;
+ }
+ }
+
+ av->dccpav_buf_ackno = ackno;
+ dccp_timestamp(sk, &av->dccpav_time);
+out:
+ return 0;
+
+out_duplicate:
+ /* Duplicate packet */
+ dccp_pr_debug("Received a dup or already considered lost "
+ "packet: %llu\n", (unsigned long long)ackno);
+ return -EILSEQ;
+}
+
+#ifdef CONFIG_IP_DCCP_DEBUG
+void dccp_ackvector_print(const u64 ackno, const unsigned char *vector, int len)
+{
+ if (!dccp_debug)
+ return;
+
+ printk("ACK vector len=%d, ackno=%llu |", len,
+ (unsigned long long)ackno);
+
+ while (len--) {
+ const u8 state = (*vector & DCCP_ACKVEC_STATE_MASK) >> 6;
+ const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
+
+ printk("%d,%d|", state, rl);
+ ++vector;
+ }
+
+ printk("\n");
+}
+
+void dccp_ackvec_print(const struct dccp_ackvec *av)
+{
+ dccp_ackvector_print(av->dccpav_buf_ackno,
+ av->dccpav_buf + av->dccpav_buf_head,
+ av->dccpav_vec_len);
+}
+#endif
+
+static void dccp_ackvec_throw_record(struct dccp_ackvec *av,
+ struct dccp_ackvec_record *avr)
+{
+ struct dccp_ackvec_record *next;
+
+ av->dccpav_buf_tail = avr->dccpavr_ack_ptr - 1;
+ if (av->dccpav_buf_tail == 0)
+ av->dccpav_buf_tail = DCCP_MAX_ACKVEC_LEN - 1;
+
+ av->dccpav_vec_len -= avr->dccpavr_sent_len;
+
+ /* free records */
+ list_for_each_entry_safe_from(avr, next, &av->dccpav_records,
+ dccpavr_node) {
+ list_del_init(&avr->dccpavr_node);
+ dccp_ackvec_record_delete(avr);
+ }
+}
+
+void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk,
+ const u64 ackno)
+{
+ struct dccp_ackvec_record *avr;
+
+ /*
+ * If we traverse backwards, it should be faster when we have large
+ * windows. We will be receiving ACKs for stuff we sent a while back
+ * -sorbo.
+ */
+ list_for_each_entry_reverse(avr, &av->dccpav_records, dccpavr_node) {
+ if (ackno == avr->dccpavr_ack_seqno) {
+#ifdef CONFIG_IP_DCCP_DEBUG
+ struct dccp_sock *dp = dccp_sk(sk);
+ const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
+ "CLIENT rx ack: " : "server rx ack: ";
+#endif
+ dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
+ "ack_ackno=%llu, ACKED!\n",
+ debug_prefix, 1,
+ (unsigned long long)avr->dccpavr_ack_seqno,
+ (unsigned long long)avr->dccpavr_ack_ackno);
+ dccp_ackvec_throw_record(av, avr);
+ break;
+ }
+ }
+}
+
+static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
+ struct sock *sk, u64 ackno,
+ const unsigned char len,
+ const unsigned char *vector)
+{
+ unsigned char i;
+ struct dccp_ackvec_record *avr;
+
+ /* Check if we actually sent an ACK vector */
+ if (list_empty(&av->dccpav_records))
+ return;
+
+ i = len;
+ /*
+ * XXX
+ * I think it might be more efficient to work backwards. See comment on
+ * rcv_ackno. -sorbo.
+ */
+ avr = list_entry(av->dccpav_records.next, struct dccp_ackvec_record,
+ dccpavr_node);
+ while (i--) {
+ const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
+ u64 ackno_end_rl;
+
+ dccp_set_seqno(&ackno_end_rl, ackno - rl);
+
+ /*
+ * If our AVR sequence number is greater than the ack, go
+ * forward in the AVR list until it is not so.
+ */
+ list_for_each_entry_from(avr, &av->dccpav_records,
+ dccpavr_node) {
+ if (!after48(avr->dccpavr_ack_seqno, ackno))
+ goto found;
+ }
+ /* End of the dccpav_records list, not found, exit */
+ break;
+found:
+ if (between48(avr->dccpavr_ack_seqno, ackno_end_rl, ackno)) {
+ const u8 state = (*vector &
+ DCCP_ACKVEC_STATE_MASK) >> 6;
+ if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) {
+#ifdef CONFIG_IP_DCCP_DEBUG
+ struct dccp_sock *dp = dccp_sk(sk);
+ const char *debug_prefix =
+ dp->dccps_role == DCCP_ROLE_CLIENT ?
+ "CLIENT rx ack: " : "server rx ack: ";
+#endif
+ dccp_pr_debug("%sACK vector 0, len=%d, "
+ "ack_seqno=%llu, ack_ackno=%llu, "
+ "ACKED!\n",
+ debug_prefix, len,
+ (unsigned long long)
+ avr->dccpavr_ack_seqno,
+ (unsigned long long)
+ avr->dccpavr_ack_ackno);
+ dccp_ackvec_throw_record(av, avr);
+ break;
+ }
+ /*
+ * If it wasn't received, continue scanning... we might
+ * find another one.
+ */
+ }
+
+ dccp_set_seqno(&ackno, ackno_end_rl - 1);
+ ++vector;
+ }
+}
+
+int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
+ const u8 opt, const u8 *value, const u8 len)
+{
+ if (len > DCCP_MAX_ACKVEC_LEN)
+ return -1;
+
+ /* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */
+ dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk,
+ DCCP_SKB_CB(skb)->dccpd_ack_seq,
+ len, value);
+ return 0;
+}
+
+static char dccp_ackvec_slab_msg[] __initdata =
+ KERN_CRIT "DCCP: Unable to create ack vectors slab caches\n";
+
+int __init dccp_ackvec_init(void)
+{
+ dccp_ackvec_slab = kmem_cache_create("dccp_ackvec",
+ sizeof(struct dccp_ackvec), 0,
+ SLAB_HWCACHE_ALIGN, NULL, NULL);
+ if (dccp_ackvec_slab == NULL)
+ goto out_err;
+
+ dccp_ackvec_record_slab =
+ kmem_cache_create("dccp_ackvec_record",
+ sizeof(struct dccp_ackvec_record),
+ 0, SLAB_HWCACHE_ALIGN, NULL, NULL);
+ 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:
+ printk(dccp_ackvec_slab_msg);
+ return -ENOBUFS;
+}
+
+void dccp_ackvec_exit(void)
+{
+ if (dccp_ackvec_slab != NULL) {
+ kmem_cache_destroy(dccp_ackvec_slab);
+ dccp_ackvec_slab = NULL;
+ }
+ if (dccp_ackvec_record_slab != NULL) {
+ kmem_cache_destroy(dccp_ackvec_record_slab);
+ dccp_ackvec_record_slab = NULL;
+ }
+}
git://git.onelab.eu / linux-2.6.git / blobdiff