sctp: implement prsctp PRIO policy

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>

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 6bcda71..8626bdd 100644 (file)
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -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];
 };

diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index b3692b5..a55e547 100644 (file)
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -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;
 }

diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 084718f..72e54a4 100644 (file)
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -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);
                }
        }

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index cfde934..1c96f47 100644 (file)
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -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;
 }
 

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 0861429..71c7dc5 100644 (file)
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -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);