[PATCH net-next 0/6] sctp: allow GSO frags to access the chunk too

[PATCH net-next 0/6] sctp: allow GSO frags to access the chunk too

[Marcelo Ricardo Leitner]

Patchset is named after the most important fix in it. First two patches
are preparing the grounds for the 3rd patch.

After the 3rd, they are not strictly logically related to the patchset,
but I kept them together as they depend on each other.

More details on patch changelogs.

Thanks!

Marcelo Ricardo Leitner (6):
  sctp: allow others to use sctp_input_cb
  sctp: reorder sctp_ulpevent and shrink msg_flags
  sctp: allow GSO frags to access the chunk too
  sctp: avoid identifying address family many times for a chunk
  sctp: do not clear chunk->ecn_ce_done flag
  sctp: only check for ECN if peer is using it

 include/net/sctp/structs.h  | 23 +++++++++++++++++++++++
 include/net/sctp/ulpevent.h | 12 ++++++------
 net/sctp/input.c            | 12 +-----------
 net/sctp/inqueue.c          |  9 ++++++++-
 net/sctp/ipv6.c             |  9 ++++-----
 net/sctp/protocol.c         |  1 +
 net/sctp/sm_make_chunk.c    | 20 ++++----------------
 net/sctp/sm_statefuns.c     |  9 +++------
 net/sctp/socket.c           | 10 +++++++---
 net/sctp/ulpevent.c         | 14 +++++++++++---
 10 files changed, 68 insertions(+), 51 deletions(-)

-- 
2.7.4

[PATCH net-next 1/6] sctp: allow others to use sctp_input_cb

[Marcelo Ricardo Leitner]

We process input path in other files too and having access to it is
nice, so move it to a header where it's shared.

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
---
 include/net/sctp/structs.h | 15 +++++++++++++++
 net/sctp/input.c           | 11 -----------
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 8626bdd3249a9283955fe81bc3255be0a18717f9..966c3a40039c12a7c525612594a51312d5de1d2a 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -59,6 +59,7 @@
 #include <linux/workqueue.h>	/* We need tq_struct.	 */
 #include <linux/sctp.h>		/* We need sctp* header structs.  */
 #include <net/sctp/auth.h>	/* We need auth specific structs */
+#include <net/ip.h>		/* For inet_skb_parm */
 
 /* A convenience structure for handling sockaddr structures.
  * We should wean ourselves off this.
@@ -1092,6 +1093,20 @@ static inline void sctp_outq_cork(struct sctp_outq *q)
 	q->cork = 1;
 }
 
+/* SCTP skb control block.
+ * sctp_input_cb is currently used on rx and sock rx queue
+ */
+struct sctp_input_cb {
+	union {
+		struct inet_skb_parm	h4;
+#if IS_ENABLED(CONFIG_IPV6)
+		struct inet6_skb_parm	h6;
+#endif
+	} header;
+	struct sctp_chunk *chunk;
+};
+#define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
+
 /* These bind address data fields common between endpoints and associations */
 struct sctp_bind_addr {
 
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 6f8e676d285ead987b0a1337beec3b29c34e0a8e..7a327ff71f08985f6ebb963d5cdc9540b23d0666 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -90,17 +90,6 @@ static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb)
 	return 0;
 }
 
-struct sctp_input_cb {
-	union {
-		struct inet_skb_parm	h4;
-#if IS_ENABLED(CONFIG_IPV6)
-		struct inet6_skb_parm	h6;
-#endif
-	} header;
-	struct sctp_chunk *chunk;
-};
-#define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
-
 /*
  * This is the routine which IP calls when receiving an SCTP packet.
  */
-- 
2.7.4

[PATCH net-next 2/6] sctp: reorder sctp_ulpevent and shrink msg_flags

[Marcelo Ricardo Leitner]

The next patch needs 8 bytes in there. sctp_ulpevent has a hole due to
bad alignment; msg_flags is using 4 bytes while it actually uses only 2, so
we shrink it, and iif member (4 bytes) which can be easily fetched from
another place once the next patch is there, so we remove it and thus
creating space for 8 bytes.

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
---
 include/net/sctp/ulpevent.h | 10 +++++-----
 net/sctp/ulpevent.c         |  4 ++--
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/net/sctp/ulpevent.h b/include/net/sctp/ulpevent.h
index cccdcfd149736b315554d64c2a556e0ad6496fc8..aa342645dbce446186d55151c3f507cf0e165b44 100644
--- a/include/net/sctp/ulpevent.h
+++ b/include/net/sctp/ulpevent.h
@@ -48,15 +48,15 @@
  */
 struct sctp_ulpevent {
 	struct sctp_association *asoc;
-	__u16 stream;
-	__u16 ssn;
-	__u16 flags;
+	unsigned int rmem_len;
 	__u32 ppid;
 	__u32 tsn;
 	__u32 cumtsn;
-	int msg_flags;
 	int iif;
-	unsigned int rmem_len;
+	__u16 stream;
+	__u16 ssn;
+	__u16 flags;
+	__u16 msg_flags;
 };
 
 /* Retrieve the skb this event sits inside of. */
diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
index d1e38308f6159c0e4da7db966c16afc6a956b554..706f5bc9f0c3083ab455ec78b963cd609a3a95b5 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -51,7 +51,7 @@ static void sctp_ulpevent_release_frag_data(struct sctp_ulpevent *event);
 
 /* Initialize an ULP event from an given skb.  */
 static void sctp_ulpevent_init(struct sctp_ulpevent *event,
-			       int msg_flags,
+			       __u16 msg_flags,
 			       unsigned int len)
 {
 	memset(event, 0, sizeof(struct sctp_ulpevent));
@@ -60,7 +60,7 @@ static void sctp_ulpevent_init(struct sctp_ulpevent *event,
 }
 
 /* Create a new sctp_ulpevent.  */
-static struct sctp_ulpevent *sctp_ulpevent_new(int size, int msg_flags,
+static struct sctp_ulpevent *sctp_ulpevent_new(int size, __u16 msg_flags,
 					       gfp_t gfp)
 {
 	struct sctp_ulpevent *event;
-- 
2.7.4

[PATCH net-next 3/6] sctp: allow GSO frags to access the chunk too

[Marcelo Ricardo Leitner]

SCTP will try to access original IP headers on sctp_recvmsg in order to
copy the addresses used. There are also other places that do similar access
to IP or even SCTP headers. But after 90017accff61 ("sctp: Add GSO
support") they aren't always there because they are only present in the
header skb.

SCTP handles the queueing of incoming data by cloning the incoming skb
and limiting to only the relevant payload. This clone has its cb updated
to something different and it's then queued on socket rx queue. Thus we
need to fix this in two moments.

For rx path, not related to socket queue yet, this patch uses a
partially copied sctp_input_cb to such GSO frags. This restores the
ability to access the headers for this part of the code.

Regarding the socket rx queue, it removes iif member from sctp_event and
also add a chunk pointer on it.

With these changes we're always able to reach the headers again.

The biggest change here is that now the sctp_chunk struct and the
original skb are only freed after the application consumed the buffer.
Note however that the original payload was already like this due to the
skb cloning.

For iif, SCTP's IPv4 code doesn't use it, so no change is necessary.
IPv6 now can fetch it directly from original's IPv6 CB as the original
skb is still accessible.

In the future we probably can simplify sctp_v*_skb_iif() stuff, as
sctp_v4_skb_iif() was called but it's return value not used, and now
it's not even called, but such cleanup is out of scope for this change.

Fixes: 90017accff61 ("sctp: Add GSO support")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
---
 include/net/sctp/structs.h  |  7 +++++++
 include/net/sctp/ulpevent.h |  2 +-
 net/sctp/inqueue.c          |  7 +++++++
 net/sctp/ipv6.c             |  9 ++++-----
 net/sctp/protocol.c         |  1 +
 net/sctp/sm_statefuns.c     |  3 ++-
 net/sctp/socket.c           | 10 +++++++---
 net/sctp/ulpevent.c         | 10 +++++++++-
 8 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 966c3a40039c12a7c525612594a51312d5de1d2a..f6f201de6fa46b3ca203c00f4970ca408edb6930 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1107,6 +1107,13 @@ struct sctp_input_cb {
 };
 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
 
+static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
+{
+	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
+
+	return chunk->head_skb ? : skb;
+}
+
 /* These bind address data fields common between endpoints and associations */
 struct sctp_bind_addr {
 
diff --git a/include/net/sctp/ulpevent.h b/include/net/sctp/ulpevent.h
index aa342645dbce446186d55151c3f507cf0e165b44..2c098cd7e7e202b6fa96e97ccb56471df27cec91 100644
--- a/include/net/sctp/ulpevent.h
+++ b/include/net/sctp/ulpevent.h
@@ -48,11 +48,11 @@
  */
 struct sctp_ulpevent {
 	struct sctp_association *asoc;
+	struct sctp_chunk *chunk;
 	unsigned int rmem_len;
 	__u32 ppid;
 	__u32 tsn;
 	__u32 cumtsn;
-	int iif;
 	__u16 stream;
 	__u16 ssn;
 	__u16 flags;
diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c
index edabbbdfca541b830526a7a52aee18c20680c19c..147d975b04559f7858b040b1f04dbc559ef2ec78 100644
--- a/net/sctp/inqueue.c
+++ b/net/sctp/inqueue.c
@@ -218,6 +218,13 @@ new_skb:
 		chunk->has_asconf = 0;
 		chunk->end_of_packet = 0;
 		chunk->ecn_ce_done = 0;
+		if (chunk->head_skb) {
+			struct sctp_input_cb
+				*cb = SCTP_INPUT_CB(chunk->skb),
+				*head_cb = SCTP_INPUT_CB(chunk->head_skb);
+
+			cb->chunk = head_cb->chunk;
+		}
 	}
 
 	chunk->chunk_hdr = ch;
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 0657d18a85bf7aa751a0456d0cc9adae3ff95e42..ae6f1a2178bab81fa14562bd1c37d1e55557b1e3 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -420,6 +420,7 @@ static void sctp_v6_from_skb(union sctp_addr *addr, struct sk_buff *skb,
 	addr->v6.sin6_flowinfo = 0; /* FIXME */
 	addr->v6.sin6_scope_id = ((struct inet6_skb_parm *)skb->cb)->iif;
 
+	/* Always called on head skb, so this is safe */
 	sh = sctp_hdr(skb);
 	if (is_saddr) {
 		*port  = sh->source;
@@ -710,8 +711,7 @@ static int sctp_v6_addr_to_user(struct sctp_sock *sp, union sctp_addr *addr)
 /* Where did this skb come from?  */
 static int sctp_v6_skb_iif(const struct sk_buff *skb)
 {
-	struct inet6_skb_parm *opt = (struct inet6_skb_parm *) skb->cb;
-	return opt->iif;
+	return IP6CB(skb)->iif;
 }
 
 /* Was this packet marked by Explicit Congestion Notification? */
@@ -780,15 +780,14 @@ static void sctp_inet6_skb_msgname(struct sk_buff *skb, char *msgname,
 	if (ip_hdr(skb)->version == 4) {
 		addr->v4.sin_family = AF_INET;
 		addr->v4.sin_port = sh->source;
-		addr->v4.sin_addr.s_addr =  ip_hdr(skb)->saddr;
+		addr->v4.sin_addr.s_addr = ip_hdr(skb)->saddr;
 	} else {
 		addr->v6.sin6_family = AF_INET6;
 		addr->v6.sin6_flowinfo = 0;
 		addr->v6.sin6_port = sh->source;
 		addr->v6.sin6_addr = ipv6_hdr(skb)->saddr;
 		if (ipv6_addr_type(&addr->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) {
-			struct sctp_ulpevent *ev = sctp_skb2event(skb);
-			addr->v6.sin6_scope_id = ev->iif;
+			addr->v6.sin6_scope_id = sctp_v6_skb_iif(skb);
 		}
 	}
 
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 3b56ae55aba36ec6e57bc2deb31fae507c5e4b54..1adb9270e31786c3a8131f0c24e58fe1b41ccc9b 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -240,6 +240,7 @@ static void sctp_v4_from_skb(union sctp_addr *addr, struct sk_buff *skb,
 	port = &addr->v4.sin_port;
 	addr->v4.sin_family = AF_INET;
 
+	/* Always called on head skb, so this is safe */
 	sh = sctp_hdr(skb);
 	if (is_saddr) {
 		*port  = sh->source;
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index f1f08c8f277bd8719299d1ed21eb23e36d55f7e2..5aabf42065e2fba9388350996310b77c58369395 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -6125,7 +6125,8 @@ static int sctp_eat_data(const struct sctp_association *asoc,
 		af = sctp_get_af_specific(
 			ipver2af(ip_hdr(chunk->skb)->version));
 
-		if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) {
+		if (af && af->is_ce(sctp_gso_headskb(chunk->skb)) &&
+		    asoc->peer.ecn_capable) {
 			/* Do real work as sideffect. */
 			sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
 					SCTP_U32(tsn));
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 71c7dc5ea62e162a95d7d318334ef9403d138b69..52fdd540a9ef153336e0c6df725ce47c9ebab11b 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2066,7 +2066,7 @@ static int sctp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 {
 	struct sctp_ulpevent *event = NULL;
 	struct sctp_sock *sp = sctp_sk(sk);
-	struct sk_buff *skb;
+	struct sk_buff *skb, *head_skb;
 	int copied;
 	int err = 0;
 	int skb_len;
@@ -2102,12 +2102,16 @@ static int sctp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	if (err)
 		goto out_free;
 
-	sock_recv_ts_and_drops(msg, sk, skb);
+	if (event->chunk && event->chunk->head_skb)
+		head_skb = event->chunk->head_skb;
+	else
+		head_skb = skb;
+	sock_recv_ts_and_drops(msg, sk, head_skb);
 	if (sctp_ulpevent_is_notification(event)) {
 		msg->msg_flags |= MSG_NOTIFICATION;
 		sp->pf->event_msgname(event, msg->msg_name, addr_len);
 	} else {
-		sp->pf->skb_msgname(skb, msg->msg_name, addr_len);
+		sp->pf->skb_msgname(head_skb, msg->msg_name, addr_len);
 	}
 
 	/* Check if we allow SCTP_NXTINFO. */
diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
index 706f5bc9f0c3083ab455ec78b963cd609a3a95b5..f6219b164b42c821c3e6f626731e97dd712c957c 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -701,6 +701,12 @@ struct sctp_ulpevent *sctp_ulpevent_make_rcvmsg(struct sctp_association *asoc,
 
 	sctp_ulpevent_receive_data(event, asoc);
 
+	/* And hold the chunk as we need it for getting the IP headers
+	 * later in recvmsg
+	 */
+	sctp_chunk_hold(chunk);
+	event->chunk = chunk;
+
 	event->stream = ntohs(chunk->subh.data_hdr->stream);
 	event->ssn = ntohs(chunk->subh.data_hdr->ssn);
 	event->ppid = chunk->subh.data_hdr->ppid;
@@ -710,11 +716,11 @@ struct sctp_ulpevent *sctp_ulpevent_make_rcvmsg(struct sctp_association *asoc,
 	}
 	event->tsn = ntohl(chunk->subh.data_hdr->tsn);
 	event->msg_flags |= chunk->chunk_hdr->flags;
-	event->iif = sctp_chunk_iif(chunk);
 
 	return event;
 
 fail_mark:
+	sctp_chunk_put(chunk);
 	kfree_skb(skb);
 fail:
 	return NULL;
@@ -1007,6 +1013,7 @@ static void sctp_ulpevent_release_data(struct sctp_ulpevent *event)
 
 done:
 	sctp_assoc_rwnd_increase(event->asoc, len);
+	sctp_chunk_put(event->chunk);
 	sctp_ulpevent_release_owner(event);
 }
 
@@ -1029,6 +1036,7 @@ static void sctp_ulpevent_release_frag_data(struct sctp_ulpevent *event)
 	}
 
 done:
+	sctp_chunk_put(event->chunk);
 	sctp_ulpevent_release_owner(event);
 }
 
-- 
2.7.4

[PATCH net-next 4/6] sctp: avoid identifying address family many times for a chunk

[Marcelo Ricardo Leitner]

Identifying address family operations during rx path is not something
expensive but it's ugly to the eye to have it done multiple times,
specially when we already validated it during initial rx processing.

This patch takes advantage of the now shared sctp_input_cb and make the
pointer to the operations readily available.

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
---
 include/net/sctp/structs.h |  1 +
 net/sctp/input.c           |  1 +
 net/sctp/inqueue.c         |  1 +
 net/sctp/sm_make_chunk.c   | 20 ++++----------------
 net/sctp/sm_statefuns.c    |  7 ++-----
 5 files changed, 9 insertions(+), 21 deletions(-)

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index f6f201de6fa46b3ca203c00f4970ca408edb6930..ce93c4b10d2620a3ac4c9efe39a86e5d231b51c2 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1104,6 +1104,7 @@ struct sctp_input_cb {
 #endif
 	} header;
 	struct sctp_chunk *chunk;
+	struct sctp_af *af;
 };
 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
 
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 7a327ff71f08985f6ebb963d5cdc9540b23d0666..30d72f7707b6df5b41679bbfc5e595d5a11130ea 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -140,6 +140,7 @@ int sctp_rcv(struct sk_buff *skb)
 	af = sctp_get_af_specific(family);
 	if (unlikely(!af))
 		goto discard_it;
+	SCTP_INPUT_CB(skb)->af = af;
 
 	/* Initialize local addresses for lookups. */
 	af->from_skb(&src, skb, 1);
diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c
index 147d975b04559f7858b040b1f04dbc559ef2ec78..8fc773f9b59a8a9ad123dd132cfa5b7f916732b6 100644
--- a/net/sctp/inqueue.c
+++ b/net/sctp/inqueue.c
@@ -224,6 +224,7 @@ new_skb:
 				*head_cb = SCTP_INPUT_CB(chunk->head_skb);
 
 			cb->chunk = head_cb->chunk;
+			cb->af = head_cb->af;
 		}
 	}
 
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 1c96f4740e67397e5f8b7134cffd4d0840220245..8c77b87a8565cb4f82c09cea65557dc9c8d1138f 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -108,14 +108,9 @@ static void sctp_control_set_owner_w(struct sctp_chunk *chunk)
 /* What was the inbound interface for this chunk? */
 int sctp_chunk_iif(const struct sctp_chunk *chunk)
 {
-	struct sctp_af *af;
-	int iif = 0;
-
-	af = sctp_get_af_specific(ipver2af(ip_hdr(chunk->skb)->version));
-	if (af)
-		iif = af->skb_iif(chunk->skb);
+	struct sk_buff *skb = chunk->skb;
 
-	return iif;
+	return SCTP_INPUT_CB(skb)->af->skb_iif(skb);
 }
 
 /* RFC 2960 3.3.2 Initiation (INIT) (1)
@@ -1600,7 +1595,6 @@ struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
 	struct sctp_association *asoc;
 	struct sk_buff *skb;
 	sctp_scope_t scope;
-	struct sctp_af *af;
 
 	/* Create the bare association.  */
 	scope = sctp_scope(sctp_source(chunk));
@@ -1610,16 +1604,10 @@ struct sctp_association *sctp_make_temp_asoc(const struct sctp_endpoint *ep,
 	asoc->temp = 1;
 	skb = chunk->skb;
 	/* Create an entry for the source address of the packet.  */
-	af = sctp_get_af_specific(ipver2af(ip_hdr(skb)->version));
-	if (unlikely(!af))
-		goto fail;
-	af->from_skb(&asoc->c.peer_addr, skb, 1);
+	SCTP_INPUT_CB(skb)->af->from_skb(&asoc->c.peer_addr, skb, 1);
+
 nodata:
 	return asoc;
-
-fail:
-	sctp_association_free(asoc);
-	return NULL;
 }
 
 /* Build a cookie representing asoc.
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 5aabf42065e2fba9388350996310b77c58369395..b7c1f7f3c8388400e51e3fbdbe099bc354559913 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -6119,13 +6119,10 @@ static int sctp_eat_data(const struct sctp_association *asoc,
 	 */
 
 	if (!chunk->ecn_ce_done) {
-		struct sctp_af *af;
+		struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af;
 		chunk->ecn_ce_done = 1;
 
-		af = sctp_get_af_specific(
-			ipver2af(ip_hdr(chunk->skb)->version));
-
-		if (af && af->is_ce(sctp_gso_headskb(chunk->skb)) &&
+		if (af->is_ce(sctp_gso_headskb(chunk->skb)) &&
 		    asoc->peer.ecn_capable) {
 			/* Do real work as sideffect. */
 			sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
-- 
2.7.4

[PATCH net-next 5/6] sctp: do not clear chunk->ecn_ce_done flag

[Marcelo Ricardo Leitner]

We should not clear that flag when switching to a new skb from a GSO skb
because it would cause ECN processing to happen multiple times per GSO
skb, which is not wanted. Instead, let it be processed once per chunk.
That is, in other words, once per IP header available.

Fixes: 90017accff61 ("sctp: Add GSO support")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
---
 net/sctp/inqueue.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c
index 8fc773f9b59a8a9ad123dd132cfa5b7f916732b6..942770675f4cc0efc9686f4e4038450f060f34ae 100644
--- a/net/sctp/inqueue.c
+++ b/net/sctp/inqueue.c
@@ -217,7 +217,6 @@ new_skb:
 		chunk->auth = 0;
 		chunk->has_asconf = 0;
 		chunk->end_of_packet = 0;
-		chunk->ecn_ce_done = 0;
 		if (chunk->head_skb) {
 			struct sctp_input_cb
 				*cb = SCTP_INPUT_CB(chunk->skb),
-- 
2.7.4

[PATCH net-next 6/6] sctp: only check for ECN if peer is using it

[Marcelo Ricardo Leitner]

Currently only read-only checks are performed up to the point on where
we check if peer is ECN capable, checks which we can avoid otherwise.
The flag ecn_ce_done is only used to perform this check once per
incoming packet, and nothing more.

Thus this patch moves the peer check up.

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
---
 net/sctp/sm_statefuns.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index b7c1f7f3c8388400e51e3fbdbe099bc354559913..d88bb2b0b69913ad5962f9a5655d413f2c210ed0 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -6118,12 +6118,11 @@ static int sctp_eat_data(const struct sctp_association *asoc,
 	 * chunk later.
 	 */
 
-	if (!chunk->ecn_ce_done) {
+	if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) {
 		struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af;
 		chunk->ecn_ce_done = 1;
 
-		if (af->is_ce(sctp_gso_headskb(chunk->skb)) &&
-		    asoc->peer.ecn_capable) {
+		if (af->is_ce(sctp_gso_headskb(chunk->skb))) {
 			/* Do real work as sideffect. */
 			sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
 					SCTP_U32(tsn));
-- 
2.7.4

Re: [PATCH net-next 0/6] sctp: allow GSO frags to access the chunk too

[David Miller]

From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: Wed, 13 Jul 2016 15:08:54 -0300

> Patchset is named after the most important fix in it. First two patches
> are preparing the grounds for the 3rd patch.
> 
> After the 3rd, they are not strictly logically related to the patchset,
> but I kept them together as they depend on each other.
> 
> More details on patch changelogs.

Series applied, thanks.