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[DCCP] ackvec: Introduce ack vector records
Based on a patch by Andrea Bittau. Signed-off-by: Andrea Bittau <a.bittau@cs.ucl.ac.uk> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andrea Bittau
David S. Miller
parent
e229c2fb33
commit
02bcf28c82
2 changed files with 173 additions and 98 deletions
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@ -22,6 +22,47 @@
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#include <net/sock.h>
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static kmem_cache_t *dccp_ackvec_slab;
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static kmem_cache_t *dccp_ackvec_record_slab;
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static struct dccp_ackvec_record *dccp_ackvec_record_new(void)
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{
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struct dccp_ackvec_record *avr =
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kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
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if (avr != NULL)
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INIT_LIST_HEAD(&avr->dccpavr_node);
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return avr;
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}
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static void dccp_ackvec_record_delete(struct dccp_ackvec_record *avr)
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{
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if (unlikely(avr == NULL))
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return;
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/* Check if deleting a linked record */
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WARN_ON(!list_empty(&avr->dccpavr_node));
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kmem_cache_free(dccp_ackvec_record_slab, avr);
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}
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static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
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struct dccp_ackvec_record *avr)
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{
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/*
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* AVRs are sorted by seqno. Since we are sending them in order, we
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* just add the AVR at the head of the list.
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* -sorbo.
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*/
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if (!list_empty(&av->dccpav_records)) {
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const struct dccp_ackvec_record *head =
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list_entry(av->dccpav_records.next,
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struct dccp_ackvec_record,
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dccpavr_node);
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BUG_ON(before48(avr->dccpavr_ack_seqno,
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head->dccpavr_ack_seqno));
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}
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list_add(&avr->dccpavr_node, &av->dccpav_records);
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}
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int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
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{
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@ -35,6 +76,14 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
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struct timeval now;
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u32 elapsed_time;
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unsigned char *to, *from;
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struct dccp_ackvec_record *avr;
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if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
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return -1;
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avr = dccp_ackvec_record_new();
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if (avr == NULL)
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return -1;
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dccp_timestamp(sk, &now);
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elapsed_time = timeval_delta(&now, &av->dccpav_time) / 10;
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@ -42,19 +91,6 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
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if (elapsed_time != 0)
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dccp_insert_option_elapsed_time(sk, skb, elapsed_time);
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if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
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return -1;
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/*
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* XXX: now we have just one ack vector sent record, so
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* we have to wait for it to be cleared.
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*
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* Of course this is not acceptable, but this is just for
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* basic testing now.
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*/
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if (av->dccpav_ack_seqno != DCCP_MAX_SEQNO + 1)
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return -1;
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DCCP_SKB_CB(skb)->dccpd_opt_len += len;
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to = skb_push(skb, len);
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@ -65,8 +101,8 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
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from = av->dccpav_buf + av->dccpav_buf_head;
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/* Check if buf_head wraps */
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if ((int)av->dccpav_buf_head + len > av->dccpav_vec_len) {
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const u32 tailsize = av->dccpav_vec_len - av->dccpav_buf_head;
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if ((int)av->dccpav_buf_head + len > DCCP_MAX_ACKVEC_LEN) {
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const u32 tailsize = DCCP_MAX_ACKVEC_LEN - av->dccpav_buf_head;
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memcpy(to, from, tailsize);
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to += tailsize;
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@ -83,21 +119,21 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
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* sequence number it used for the ack packet; ack_ptr will equal
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* buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
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* equal buf_nonce.
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*
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* This implemention uses just one ack record for now.
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*/
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av->dccpav_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
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av->dccpav_ack_ptr = av->dccpav_buf_head;
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av->dccpav_ack_ackno = av->dccpav_buf_ackno;
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av->dccpav_ack_nonce = av->dccpav_buf_nonce;
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av->dccpav_sent_len = av->dccpav_vec_len;
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avr->dccpavr_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
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avr->dccpavr_ack_ptr = av->dccpav_buf_head;
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avr->dccpavr_ack_ackno = av->dccpav_buf_ackno;
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avr->dccpavr_ack_nonce = av->dccpav_buf_nonce;
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avr->dccpavr_sent_len = av->dccpav_vec_len;
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dccp_ackvec_insert_avr(av, avr);
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dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, "
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"ack_ackno=%llu\n",
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debug_prefix, av->dccpav_sent_len,
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(unsigned long long)av->dccpav_ack_seqno,
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(unsigned long long)av->dccpav_ack_ackno);
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return -1;
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debug_prefix, avr->dccpavr_sent_len,
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(unsigned long long)avr->dccpavr_ack_seqno,
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(unsigned long long)avr->dccpavr_ack_ackno);
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return 0;
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}
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struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
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@ -107,13 +143,13 @@ struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
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if (av != NULL) {
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av->dccpav_buf_head =
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av->dccpav_buf_tail = DCCP_MAX_ACKVEC_LEN - 1;
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av->dccpav_buf_ackno =
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av->dccpav_ack_ackno = av->dccpav_ack_seqno = ~0LLU;
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av->dccpav_buf_ackno = DCCP_MAX_SEQNO + 1;
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av->dccpav_buf_nonce = av->dccpav_buf_nonce = 0;
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av->dccpav_ack_ptr = 0;
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av->dccpav_time.tv_sec = 0;
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av->dccpav_time.tv_usec = 0;
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av->dccpav_sent_len = av->dccpav_vec_len = 0;
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INIT_LIST_HEAD(&av->dccpav_records);
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}
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return av;
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@ -121,6 +157,9 @@ struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
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void dccp_ackvec_free(struct dccp_ackvec *av)
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{
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if (unlikely(av == NULL))
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return;
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WARN_ON(!list_empty(&av->dccpav_records));
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kmem_cache_free(dccp_ackvec_slab, av);
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}
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@ -299,44 +338,50 @@ void dccp_ackvec_print(const struct dccp_ackvec *av)
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}
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#endif
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static void dccp_ackvec_throw_away_ack_record(struct dccp_ackvec *av)
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static void dccp_ackvec_throw_record(struct dccp_ackvec *av,
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struct dccp_ackvec_record *avr)
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{
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/*
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* As we're keeping track of the ack vector size (dccpav_vec_len) and
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* the sent ack vector size (dccpav_sent_len) we don't need
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* dccpav_buf_tail at all, but keep this code here as in the future
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* we'll implement a vector of ack records, as suggested in
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* draft-ietf-dccp-spec-11.txt Appendix A. -acme
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*/
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#if 0
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u32 new_buf_tail = av->dccpav_ack_ptr + 1;
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if (new_buf_tail >= av->dccpav_vec_len)
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new_buf_tail -= av->dccpav_vec_len;
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av->dccpav_buf_tail = new_buf_tail;
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#endif
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av->dccpav_vec_len -= av->dccpav_sent_len;
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struct dccp_ackvec_record *next;
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av->dccpav_buf_tail = avr->dccpavr_ack_ptr - 1;
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if (av->dccpav_buf_tail == 0)
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av->dccpav_buf_tail = DCCP_MAX_ACKVEC_LEN - 1;
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av->dccpav_vec_len -= avr->dccpavr_sent_len;
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/* free records */
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list_for_each_entry_safe_from(avr, next, &av->dccpav_records,
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dccpavr_node) {
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list_del_init(&avr->dccpavr_node);
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dccp_ackvec_record_delete(avr);
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}
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}
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void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk,
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const u64 ackno)
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{
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/* Check if we actually sent an ACK vector */
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if (av->dccpav_ack_seqno == DCCP_MAX_SEQNO + 1)
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return;
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struct dccp_ackvec_record *avr;
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if (ackno == av->dccpav_ack_seqno) {
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/*
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* If we traverse backwards, it should be faster when we have large
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* windows. We will be receiving ACKs for stuff we sent a while back
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* -sorbo.
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*/
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list_for_each_entry_reverse(avr, &av->dccpav_records, dccpavr_node) {
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if (ackno == avr->dccpavr_ack_seqno) {
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#ifdef CONFIG_IP_DCCP_DEBUG
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struct dccp_sock *dp = dccp_sk(sk);
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const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
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"CLIENT rx ack: " : "server rx ack: ";
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struct dccp_sock *dp = dccp_sk(sk);
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const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
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"CLIENT rx ack: " : "server rx ack: ";
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#endif
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dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
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"ack_ackno=%llu, ACKED!\n",
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debug_prefix, 1,
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(unsigned long long)av->dccpav_ack_seqno,
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(unsigned long long)av->dccpav_ack_ackno);
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dccp_ackvec_throw_away_ack_record(av);
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av->dccpav_ack_seqno = DCCP_MAX_SEQNO + 1;
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dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
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"ack_ackno=%llu, ACKED!\n",
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debug_prefix, 1,
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(unsigned long long)avr->dccpavr_ack_seqno,
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(unsigned long long)avr->dccpavr_ack_ackno);
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dccp_ackvec_throw_record(av, avr);
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break;
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}
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}
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}
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@ -346,28 +391,20 @@ static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
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const unsigned char *vector)
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{
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unsigned char i;
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struct dccp_ackvec_record *avr;
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/* Check if we actually sent an ACK vector */
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if (av->dccpav_ack_seqno == DCCP_MAX_SEQNO + 1)
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if (list_empty(&av->dccpav_records))
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return;
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/*
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* We're in the receiver half connection, so if the received an ACK
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* vector ackno (e.g. 50) before dccpav_ack_seqno (e.g. 52), we're
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* not interested.
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*
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* Extra explanation with example:
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*
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* if we received an ACK vector with ackno 50, it can only be acking
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* 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent).
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*/
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/* dccp_pr_debug("is %llu < %llu? ", ackno, av->dccpav_ack_seqno); */
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if (before48(ackno, av->dccpav_ack_seqno)) {
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/* dccp_pr_debug_cat("yes\n"); */
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return;
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}
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/* dccp_pr_debug_cat("no\n"); */
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i = len;
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/*
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* XXX
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* I think it might be more efficient to work backwards. See comment on
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* rcv_ackno. -sorbo.
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*/
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avr = list_entry(av->dccpav_records.next, struct dccp_ackvec_record,
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dccpavr_node);
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while (i--) {
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const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
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u64 ackno_end_rl;
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@ -375,14 +412,20 @@ static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
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dccp_set_seqno(&ackno_end_rl, ackno - rl);
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/*
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* dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl,
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* av->dccpav_ack_seqno, ackno);
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* If our AVR sequence number is greater than the ack, go
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* forward in the AVR list until it is not so.
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*/
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if (between48(av->dccpav_ack_seqno, ackno_end_rl, ackno)) {
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list_for_each_entry_from(avr, &av->dccpav_records,
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dccpavr_node) {
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if (!after48(avr->dccpavr_ack_seqno, ackno))
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goto found;
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}
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/* End of the dccpav_records list, not found, exit */
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break;
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found:
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if (between48(avr->dccpavr_ack_seqno, ackno_end_rl, ackno)) {
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const u8 state = (*vector &
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DCCP_ACKVEC_STATE_MASK) >> 6;
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/* dccp_pr_debug_cat("yes\n"); */
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if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) {
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#ifdef CONFIG_IP_DCCP_DEBUG
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struct dccp_sock *dp = dccp_sk(sk);
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@ -395,19 +438,16 @@ static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
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"ACKED!\n",
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debug_prefix, len,
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(unsigned long long)
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av->dccpav_ack_seqno,
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avr->dccpavr_ack_seqno,
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(unsigned long long)
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av->dccpav_ack_ackno);
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dccp_ackvec_throw_away_ack_record(av);
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avr->dccpavr_ack_ackno);
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dccp_ackvec_throw_record(av, avr);
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}
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/*
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* If dccpav_ack_seqno was not received, no problem
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* we'll send another ACK vector.
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* If it wasn't received, continue scanning... we might
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* find another one.
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*/
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av->dccpav_ack_seqno = DCCP_MAX_SEQNO + 1;
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break;
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}
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/* dccp_pr_debug_cat("no\n"); */
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dccp_set_seqno(&ackno, ackno_end_rl - 1);
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++vector;
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@ -428,19 +468,31 @@ int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
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}
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static char dccp_ackvec_slab_msg[] __initdata =
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KERN_CRIT "DCCP: Unable to create ack vectors slab cache\n";
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KERN_CRIT "DCCP: Unable to create ack vectors slab caches\n";
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int __init dccp_ackvec_init(void)
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{
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dccp_ackvec_slab = kmem_cache_create("dccp_ackvec",
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sizeof(struct dccp_ackvec), 0,
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SLAB_HWCACHE_ALIGN, NULL, NULL);
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if (dccp_ackvec_slab == NULL) {
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printk(dccp_ackvec_slab_msg);
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return -ENOBUFS;
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}
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if (dccp_ackvec_slab == NULL)
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goto out_err;
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dccp_ackvec_record_slab =
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kmem_cache_create("dccp_ackvec_record",
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sizeof(struct dccp_ackvec_record),
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0, SLAB_HWCACHE_ALIGN, NULL, NULL);
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if (dccp_ackvec_record_slab == NULL)
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goto out_destroy_slab;
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return 0;
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out_destroy_slab:
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kmem_cache_destroy(dccp_ackvec_slab);
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dccp_ackvec_slab = NULL;
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out_err:
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printk(dccp_ackvec_slab_msg);
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return -ENOBUFS;
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}
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void dccp_ackvec_exit(void)
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@ -449,4 +501,8 @@ void dccp_ackvec_exit(void)
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kmem_cache_destroy(dccp_ackvec_slab);
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dccp_ackvec_slab = NULL;
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}
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if (dccp_ackvec_record_slab != NULL) {
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kmem_cache_destroy(dccp_ackvec_record_slab);
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dccp_ackvec_record_slab = NULL;
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}
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}
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@ -13,6 +13,7 @@
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#include <linux/config.h>
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#include <linux/compiler.h>
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#include <linux/list.h>
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#include <linux/time.h>
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#include <linux/types.h>
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@ -42,11 +43,8 @@
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* Ack Vectors it has recently sent. For each packet sent carrying an
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||||
* Ack Vector, it remembers four variables:
|
||||
*
|
||||
* @dccpav_ack_seqno - the Sequence Number used for the packet
|
||||
* (HC-Receiver seqno)
|
||||
* @dccpav_ack_ptr - the value of buf_head at the time of acknowledgement.
|
||||
* @dccpav_ack_ackno - the Acknowledgement Number used for the packet
|
||||
* (HC-Sender seqno)
|
||||
* @dccpav_records - list of dccp_ackvec_record
|
||||
* @dccpav_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
|
||||
*
|
||||
* @dccpav_time - the time in usecs
|
||||
|
|
@ -54,8 +52,7 @@
|
|||
*/
|
||||
struct dccp_ackvec {
|
||||
u64 dccpav_buf_ackno;
|
||||
u64 dccpav_ack_seqno;
|
||||
u64 dccpav_ack_ackno;
|
||||
struct list_head dccpav_records;
|
||||
struct timeval dccpav_time;
|
||||
u8 dccpav_buf_head;
|
||||
u8 dccpav_buf_tail;
|
||||
|
|
@ -67,6 +64,28 @@ struct dccp_ackvec {
|
|||
u8 dccpav_buf[DCCP_MAX_ACKVEC_LEN];
|
||||
};
|
||||
|
||||
/** struct dccp_ackvec_record - ack vector record
|
||||
*
|
||||
* ACK vector record as defined in Appendix A of spec.
|
||||
*
|
||||
* The list is sorted by dccpavr_ack_seqno
|
||||
*
|
||||
* @dccpavr_node - node in dccpav_records
|
||||
* @dccpavr_ack_seqno - sequence number of the packet this record was sent on
|
||||
* @dccpavr_ack_ackno - sequence number being acknowledged
|
||||
* @dccpavr_ack_ptr - pointer into dccpav_buf where this record starts
|
||||
* @dccpavr_ack_nonce - dccpav_ack_nonce at the time this record was sent
|
||||
* @dccpavr_sent_len - lenght of the record in dccpav_buf
|
||||
*/
|
||||
struct dccp_ackvec_record {
|
||||
struct list_head dccpavr_node;
|
||||
u64 dccpavr_ack_seqno;
|
||||
u64 dccpavr_ack_ackno;
|
||||
u8 dccpavr_ack_ptr;
|
||||
u8 dccpavr_ack_nonce;
|
||||
u8 dccpavr_sent_len;
|
||||
};
|
||||
|
||||
struct sock;
|
||||
struct sk_buff;
|
||||
|
||||
|
|
|
|||
Loading…
Reference in a new issue