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sctp: implement prsctp PRIO policy

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prsctp PRIO policy is a policy to abandon lower priority chunks when
asoc doesn't have enough snd buffer, so that the current chunk with
higher priority can be queued successfully.

Similar to TTL/RTX policy, we will set the priority of the chunk to
prsctp_param with sinfo->sinfo_timetolive in sctp_set_prsctp_policy().
So if PRIO policy is enabled, msg->expire_at won't work.

asoc->sent_cnt_removable will record how many chunks can be checked to
remove. If priority policy is enabled, when the chunk is queued into
the out_queue, we will increase sent_cnt_removable. When the chunk is
moved to abandon_queue or dequeue and free, we will decrease
sent_cnt_removable.

In sctp_sendmsg, we will check if there is enough snd buffer for current
msg and if sent_cnt_removable is not 0. Then try to abandon chunks in
sctp_prune_prsctp when sendmsg from the retransmit/transmited queue, and
free chunks from out_queue in right order until the abandon+free size >
msg_len - sctp_wfree. For the abandon size, we have to wait until it
sends FORWARD TSN, receives the sack and the chunks are really freed.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Xin Long 2016-07-09 19:47:45 +08:00 committed by David S. Miller
parent 01aadb3af6
commit 8dbdf1f5b0
5 changed files with 109 additions and 1 deletions
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4
include/net/sctp/structs.h
View File

@ -1084,6 +1084,8 @@ void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
sctp_retransmit_reason_t);
void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
int sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
void sctp_prsctp_prune(struct sctp_association *asoc,
struct sctp_sndrcvinfo *sinfo, int msg_len);
/* Uncork and flush an outqueue. */
static inline void sctp_outq_cork(struct sctp_outq *q)
{
@ -1864,6 +1866,8 @@ struct sctp_association {
struct sctp_priv_assoc_stats stats;
int sent_cnt_removable;
__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
};

1
net/sctp/chunk.c
View File

@ -360,6 +360,7 @@ int sctp_chunk_abandoned(struct sctp_chunk *chunk)
chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
return 1;
}
/* PRIO policy is processed by sendmsg, not here */
return 0;
}

99
net/sctp/outqueue.c
View File

@ -326,6 +326,9 @@ int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk, gfp_t gfp)
sctp_chunk_hold(chunk);
sctp_outq_tail_data(q, chunk);
if (chunk->asoc->prsctp_enable &&
SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
chunk->asoc->sent_cnt_removable++;
if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS);
else
@ -372,6 +375,96 @@ static void sctp_insert_list(struct list_head *head, struct list_head *new)
list_add_tail(new, head);
}
static int sctp_prsctp_prune_sent(struct sctp_association *asoc,
struct sctp_sndrcvinfo *sinfo,
struct list_head *queue, int msg_len)
{
struct sctp_chunk *chk, *temp;
list_for_each_entry_safe(chk, temp, queue, transmitted_list) {
if (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
chk->prsctp_param <= sinfo->sinfo_timetolive)
continue;
list_del_init(&chk->transmitted_list);
sctp_insert_list(&asoc->outqueue.abandoned,
&chk->transmitted_list);
asoc->sent_cnt_removable--;
asoc->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
if (!chk->tsn_gap_acked) {
if (chk->transport)
chk->transport->flight_size -=
sctp_data_size(chk);
asoc->outqueue.outstanding_bytes -= sctp_data_size(chk);
}
msg_len -= SCTP_DATA_SNDSIZE(chk) +
sizeof(struct sk_buff) +
sizeof(struct sctp_chunk);
if (msg_len <= 0)
break;
}
return msg_len;
}
static int sctp_prsctp_prune_unsent(struct sctp_association *asoc,
struct sctp_sndrcvinfo *sinfo,
struct list_head *queue, int msg_len)
{
struct sctp_chunk *chk, *temp;
list_for_each_entry_safe(chk, temp, queue, list) {
if (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
chk->prsctp_param <= sinfo->sinfo_timetolive)
continue;
list_del_init(&chk->list);
asoc->sent_cnt_removable--;
asoc->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;
msg_len -= SCTP_DATA_SNDSIZE(chk) +
sizeof(struct sk_buff) +
sizeof(struct sctp_chunk);
sctp_chunk_free(chk);
if (msg_len <= 0)
break;
}
return msg_len;
}
/* Abandon the chunks according their priorities */
void sctp_prsctp_prune(struct sctp_association *asoc,
struct sctp_sndrcvinfo *sinfo, int msg_len)
{
struct sctp_transport *transport;
if (!asoc->prsctp_enable || !asoc->sent_cnt_removable)
return;
msg_len = sctp_prsctp_prune_sent(asoc, sinfo,
&asoc->outqueue.retransmit,
msg_len);
if (msg_len <= 0)
return;
list_for_each_entry(transport, &asoc->peer.transport_addr_list,
transports) {
msg_len = sctp_prsctp_prune_sent(asoc, sinfo,
&transport->transmitted,
msg_len);
if (msg_len <= 0)
return;
}
sctp_prsctp_prune_unsent(asoc, sinfo,
&asoc->outqueue.out_chunk_list,
msg_len);
}
/* Mark all the eligible packets on a transport for retransmission. */
void sctp_retransmit_mark(struct sctp_outq *q,
struct sctp_transport *transport,
@ -962,6 +1055,9 @@ static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp)
/* Mark as failed send. */
sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
if (asoc->prsctp_enable &&
SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
asoc->sent_cnt_removable--;
sctp_chunk_free(chunk);
continue;
}
@ -1251,6 +1347,9 @@ int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk)
tsn = ntohl(tchunk->subh.data_hdr->tsn);
if (TSN_lte(tsn, ctsn)) {
list_del_init(&tchunk->transmitted_list);
if (asoc->prsctp_enable &&
SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
asoc->sent_cnt_removable--;
sctp_chunk_free(tchunk);
}
}

3
net/sctp/sm_make_chunk.c
View File

@ -720,7 +720,8 @@ static void sctp_set_prsctp_policy(struct sctp_chunk *chunk,
if (SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags))
chunk->prsctp_param =
jiffies + msecs_to_jiffies(sinfo->sinfo_timetolive);
else if (SCTP_PR_RTX_ENABLED(sinfo->sinfo_flags))
else if (SCTP_PR_RTX_ENABLED(sinfo->sinfo_flags) ||
SCTP_PR_PRIO_ENABLED(sinfo->sinfo_flags))
chunk->prsctp_param = sinfo->sinfo_timetolive;
}

3
net/sctp/socket.c
View File

@ -1914,6 +1914,9 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
goto out_free;
}
if (sctp_wspace(asoc) < msg_len)
sctp_prsctp_prune(asoc, sinfo, msg_len - sctp_wspace(asoc));
timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
if (!sctp_wspace(asoc)) {
err = sctp_wait_for_sndbuf(asoc, &timeo, msg_len);