Commit 02bcf28c authored by Andrea Bittau's avatar Andrea Bittau Committed by David S. Miller
Browse files

[DCCP] ackvec: Introduce ack vector records



Based on a patch by Andrea Bittau.
Signed-off-by: default avatarAndrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e229c2fb
......@@ -22,6 +22,47 @@
#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)
{
......@@ -35,6 +76,14 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
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;
avr = dccp_ackvec_record_new();
if (avr == NULL)
return -1;
dccp_timestamp(sk, &now);
elapsed_time = timeval_delta(&now, &av->dccpav_time) / 10;
......@@ -42,19 +91,6 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
if (elapsed_time != 0)
dccp_insert_option_elapsed_time(sk, skb, elapsed_time);
if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
return -1;
/*
* XXX: now we have just one ack vector sent record, so
* we have to wait for it to be cleared.
*
* Of course this is not acceptable, but this is just for
* basic testing now.
*/
if (av->dccpav_ack_seqno != DCCP_MAX_SEQNO + 1)
return -1;
DCCP_SKB_CB(skb)->dccpd_opt_len += len;
to = skb_push(skb, len);
......@@ -65,8 +101,8 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
from = av->dccpav_buf + av->dccpav_buf_head;
/* Check if buf_head wraps */
if ((int)av->dccpav_buf_head + len > av->dccpav_vec_len) {
const u32 tailsize = av->dccpav_vec_len - av->dccpav_buf_head;
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;
......@@ -83,21 +119,21 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
* 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.
*
* This implemention uses just one ack record for now.
*/
av->dccpav_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
av->dccpav_ack_ptr = av->dccpav_buf_head;
av->dccpav_ack_ackno = av->dccpav_buf_ackno;
av->dccpav_ack_nonce = av->dccpav_buf_nonce;
av->dccpav_sent_len = av->dccpav_vec_len;
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, av->dccpav_sent_len,
(unsigned long long)av->dccpav_ack_seqno,
(unsigned long long)av->dccpav_ack_ackno);
return -1;
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)
......@@ -107,13 +143,13 @@ struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
if (av != NULL) {
av->dccpav_buf_head =
av->dccpav_buf_tail = DCCP_MAX_ACKVEC_LEN - 1;
av->dccpav_buf_ackno =
av->dccpav_ack_ackno = av->dccpav_ack_seqno = ~0LLU;
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;
......@@ -121,6 +157,9 @@ struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
void dccp_ackvec_free(struct dccp_ackvec *av)
{
if (unlikely(av == NULL))
return;
WARN_ON(!list_empty(&av->dccpav_records));
kmem_cache_free(dccp_ackvec_slab, av);
}
......@@ -299,44 +338,50 @@ void dccp_ackvec_print(const struct dccp_ackvec *av)
}
#endif
static void dccp_ackvec_throw_away_ack_record(struct dccp_ackvec *av)
static void dccp_ackvec_throw_record(struct dccp_ackvec *av,
struct dccp_ackvec_record *avr)
{
/*
* As we're keeping track of the ack vector size (dccpav_vec_len) and
* the sent ack vector size (dccpav_sent_len) we don't need
* dccpav_buf_tail at all, but keep this code here as in the future
* we'll implement a vector of ack records, as suggested in
* draft-ietf-dccp-spec-11.txt Appendix A. -acme
*/
#if 0
u32 new_buf_tail = av->dccpav_ack_ptr + 1;
if (new_buf_tail >= av->dccpav_vec_len)
new_buf_tail -= av->dccpav_vec_len;
av->dccpav_buf_tail = new_buf_tail;
#endif
av->dccpav_vec_len -= av->dccpav_sent_len;
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)
{
/* Check if we actually sent an ACK vector */
if (av->dccpav_ack_seqno == DCCP_MAX_SEQNO + 1)
return;
struct dccp_ackvec_record *avr;
if (ackno == av->dccpav_ack_seqno) {
/*
* 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: ";
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)av->dccpav_ack_seqno,
(unsigned long long)av->dccpav_ack_ackno);
dccp_ackvec_throw_away_ack_record(av);
av->dccpav_ack_seqno = DCCP_MAX_SEQNO + 1;
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;
}
}
}
......@@ -346,28 +391,20 @@ static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
const unsigned char *vector)
{
unsigned char i;
struct dccp_ackvec_record *avr;
/* Check if we actually sent an ACK vector */
if (av->dccpav_ack_seqno == DCCP_MAX_SEQNO + 1)
if (list_empty(&av->dccpav_records))
return;
/*
* We're in the receiver half connection, so if the received an ACK
* vector ackno (e.g. 50) before dccpav_ack_seqno (e.g. 52), we're
* not interested.
*
* Extra explanation with example:
*
* if we received an ACK vector with ackno 50, it can only be acking
* 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent).
*/
/* dccp_pr_debug("is %llu < %llu? ", ackno, av->dccpav_ack_seqno); */
if (before48(ackno, av->dccpav_ack_seqno)) {
/* dccp_pr_debug_cat("yes\n"); */
return;
}
/* dccp_pr_debug_cat("no\n"); */
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;
......@@ -375,14 +412,20 @@ static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
dccp_set_seqno(&ackno_end_rl, ackno - rl);
/*
* dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl,
* av->dccpav_ack_seqno, ackno);
* If our AVR sequence number is greater than the ack, go
* forward in the AVR list until it is not so.
*/
if (between48(av->dccpav_ack_seqno, ackno_end_rl, ackno)) {
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;
/* dccp_pr_debug_cat("yes\n"); */
if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) {
#ifdef CONFIG_IP_DCCP_DEBUG
struct dccp_sock *dp = dccp_sk(sk);
......@@ -395,19 +438,16 @@ static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
"ACKED!\n",
debug_prefix, len,
(unsigned long long)
av->dccpav_ack_seqno,
avr->dccpavr_ack_seqno,
(unsigned long long)
av->dccpav_ack_ackno);
dccp_ackvec_throw_away_ack_record(av);
avr->dccpavr_ack_ackno);
dccp_ackvec_throw_record(av, avr);
}
/*
* If dccpav_ack_seqno was not received, no problem
* we'll send another ACK vector.
* If it wasn't received, continue scanning... we might
* find another one.
*/
av->dccpav_ack_seqno = DCCP_MAX_SEQNO + 1;
break;
}
/* dccp_pr_debug_cat("no\n"); */
dccp_set_seqno(&ackno, ackno_end_rl - 1);
++vector;
......@@ -428,19 +468,31 @@ int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
}
static char dccp_ackvec_slab_msg[] __initdata =
KERN_CRIT "DCCP: Unable to create ack vectors slab cache\n";
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) {
printk(dccp_ackvec_slab_msg);
return -ENOBUFS;
}
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)
......@@ -449,4 +501,8 @@ void dccp_ackvec_exit(void)
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;
}
}
......@@ -13,6 +13,7 @@
#include <linux/config.h>
#include <linux/compiler.h>
#include <linux/list.h>
#include <linux/time.h>
#include <linux/types.h>
......@@ -42,11 +43,8 @@
* Ack Vectors it has recently sent. For each packet sent carrying an
* 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;
......
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