sctp: implement renege_events for sctp_stream_interleave

renege_events is added as a member of sctp_stream_interleave, used to
renege some old data or idata in reasm or lobby queue properly to free
some memory for the new data when there's memory stress.

It defines sctp_renege_events for idata, and leaves sctp_ulpq_renege
as it is for data.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 119 insertions, 10 deletions

diff --git a/include/net/sctp/stream_interleave.h b/include/net/sctp/stream_interleave.h
index a0f61bc08ae8..16a71cb2b098 100644
--- a/include/net/sctp/stream_interleave.h
+++ b/include/net/sctp/stream_interleave.h
@@ -43,6 +43,8 @@ struct sctp_stream_interleave {
                                  struct sctp_chunk *chunk, gfp_t gfp);
         int     (*enqueue_event)(struct sctp_ulpq *ulpq,
                                  struct sctp_ulpevent *event);
+        void    (*renege_events)(struct sctp_ulpq *ulpq,
+                                 struct sctp_chunk *chunk, gfp_t gfp);
 };
 
 void sctp_stream_interleave_init(struct sctp_stream *stream);
diff --git a/include/net/sctp/ulpqueue.h b/include/net/sctp/ulpqueue.h
index e0dce07b8794..eb98c7150a56 100644
--- a/include/net/sctp/ulpqueue.h
+++ b/include/net/sctp/ulpqueue.h
@@ -76,11 +76,8 @@ int sctp_clear_pd(struct sock *sk, struct sctp_association *asoc);
 void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn);
 
 void sctp_ulpq_reasm_flushtsn(struct sctp_ulpq *, __u32);
-#endif /* __sctp_ulpqueue_h__ */
-
-
-
-
-
 
+__u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
+                            struct sk_buff_head *list, __u16 needed);
 
+#endif /* __sctp_ulpqueue_h__ */
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index f4e5ecade936..2bec17ad7fc9 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -1735,8 +1735,9 @@ static int sctp_cmd_interpreter(enum sctp_event event_type,
                         break;
 
                 case SCTP_CMD_RENEGE:
-                        sctp_ulpq_renege(&asoc->ulpq, cmd->obj.chunk,
-                                         GFP_ATOMIC);
+                        asoc->stream.si->renege_events(&asoc->ulpq,
+                                                       cmd->obj.chunk,
+                                                       GFP_ATOMIC);
                         break;
 
                 case SCTP_CMD_SETUP_T4:
diff --git a/net/sctp/stream_interleave.c b/net/sctp/stream_interleave.c
index e85397200230..d62ad5c62092 100644
--- a/net/sctp/stream_interleave.c
+++ b/net/sctp/stream_interleave.c
@@ -545,6 +545,113 @@ static int sctp_ulpevent_idata(struct sctp_ulpq *ulpq,
         return event_eor;
 }
 
+static struct sctp_ulpevent *sctp_intl_retrieve_first(struct sctp_ulpq *ulpq)
+{
+        struct sctp_stream_in *csin, *sin = NULL;
+        struct sk_buff *first_frag = NULL;
+        struct sk_buff *last_frag = NULL;
+        struct sctp_ulpevent *retval;
+        struct sk_buff *pos;
+        __u32 next_fsn = 0;
+        __u16 sid = 0;
+
+        skb_queue_walk(&ulpq->reasm, pos) {
+                struct sctp_ulpevent *cevent = sctp_skb2event(pos);
+
+                csin = sctp_stream_in(ulpq->asoc, cevent->stream);
+                if (csin->pd_mode)
+                        continue;
+
+                switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
+                case SCTP_DATA_FIRST_FRAG:
+                        if (first_frag)
+                                goto out;
+                        if (cevent->mid == csin->mid) {
+                                first_frag = pos;
+                                last_frag = pos;
+                                next_fsn = 0;
+                                sin = csin;
+                                sid = cevent->stream;
+                        }
+                        break;
+                case SCTP_DATA_MIDDLE_FRAG:
+                        if (!first_frag)
+                                break;
+                        if (cevent->stream == sid &&
+                            cevent->mid == sin->mid &&
+                            cevent->fsn == next_fsn) {
+                                next_fsn++;
+                                last_frag = pos;
+                        } else {
+                                goto out;
+                        }
+                        break;
+                case SCTP_DATA_LAST_FRAG:
+                        if (first_frag)
+                                goto out;
+                        break;
+                default:
+                        break;
+                }
+        }
+
+        if (!first_frag)
+                return NULL;
+
+out:
+        retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk),
+                                             &ulpq->reasm, first_frag,
+                                             last_frag);
+        if (retval) {
+                sin->fsn = next_fsn;
+                sin->pd_mode = 1;
+        }
+
+        return retval;
+}
+
+static void sctp_intl_start_pd(struct sctp_ulpq *ulpq, gfp_t gfp)
+{
+        struct sctp_ulpevent *event;
+
+        if (skb_queue_empty(&ulpq->reasm))
+                return;
+
+        do {
+                event = sctp_intl_retrieve_first(ulpq);
+                if (event)
+                        sctp_enqueue_event(ulpq, event);
+        } while (event);
+}
+
+static void sctp_renege_events(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
+                               gfp_t gfp)
+{
+        struct sctp_association *asoc = ulpq->asoc;
+        __u32 freed = 0;
+        __u16 needed;
+
+        if (chunk) {
+                needed = ntohs(chunk->chunk_hdr->length);
+                needed -= sizeof(struct sctp_idata_chunk);
+        } else {
+                needed = SCTP_DEFAULT_MAXWINDOW;
+        }
+
+        if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) {
+                freed = sctp_ulpq_renege_list(ulpq, &ulpq->lobby, needed);
+                if (freed < needed)
+                        freed += sctp_ulpq_renege_list(ulpq, &ulpq->reasm,
+                                                       needed);
+        }
+
+        if (chunk && freed >= needed)
+                if (sctp_ulpevent_idata(ulpq, chunk, gfp) <= 0)
+                        sctp_intl_start_pd(ulpq, gfp);
+
+        sk_mem_reclaim(asoc->base.sk);
+}
+
 static struct sctp_stream_interleave sctp_stream_interleave_0 = {
         .data_chunk_len         = sizeof(struct sctp_data_chunk),
         /* DATA process functions */
@@ -553,6 +660,7 @@ static struct sctp_stream_interleave sctp_stream_interleave_0 = {
         .validate_data          = sctp_validate_data,
         .ulpevent_data          = sctp_ulpq_tail_data,
         .enqueue_event          = sctp_ulpq_tail_event,
+        .renege_events          = sctp_ulpq_renege,
 };
 
 static struct sctp_stream_interleave sctp_stream_interleave_1 = {
@@ -563,6 +671,7 @@ static struct sctp_stream_interleave sctp_stream_interleave_1 = {
         .validate_data          = sctp_validate_idata,
         .ulpevent_data          = sctp_ulpevent_idata,
         .enqueue_event          = sctp_enqueue_event,
+        .renege_events          = sctp_renege_events,
 };
 
 void sctp_stream_interleave_init(struct sctp_stream *stream)
diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
index 0d07f2a6cb35..76ec5149a093 100644
--- a/net/sctp/ulpqueue.c
+++ b/net/sctp/ulpqueue.c
@@ -978,8 +978,8 @@ void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn)
         sctp_ulpq_reap_ordered(ulpq, sid);
 }
 
-static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
-                struct sk_buff_head *list, __u16 needed)
+__u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq, struct sk_buff_head *list,
+                            __u16 needed)
 {
         __u16 freed = 0;
         __u32 tsn, last_tsn;