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Date: Fri, 4 May 2007 16:22:54 -0400
From: Vlad Yasevich <vladislav.yasevich@...com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, lksctp-developers@...ts.sourceforge.net,
Vlad Yasevich <vladislav.yasevich@...com>
Subject: [PATCH 3/4] [SCTP] Set assoc_id correctly during INIT collision.
During the INIT/COOKIE-ACK collision cases, it's possible to get
into a situation where the association id is not yet set at the time
of the user event generation. As a result, user events have an
association id set to 0 which will confuse applications.
This happens if we hit case B of duplicate cookie processing.
In the particular example found and provided by Oscar Isaula
<Oscar.Isaula@...orola.com>, flow looks like this:
A B
---- INIT-------> (lost)
<---------INIT------
---- INIT-ACK--->
<------ Cookie ECHO
---
include/net/sctp/command.h | 2 ++
include/net/sctp/structs.h | 1 +
net/sctp/associola.c | 29 +++++++++++++++++++++++++++++
net/sctp/sm_make_chunk.c | 15 ++-------------
net/sctp/sm_sideeffect.c | 35 +++++++++++++++++++++++++++++++++++
net/sctp/sm_statefuns.c | 29 +++++++++++------------------
6 files changed, 80 insertions(+), 31 deletions(-)
diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h
index 6114c4f..f56c8d6 100644
--- a/include/net/sctp/command.h
+++ b/include/net/sctp/command.h
@@ -100,6 +100,8 @@ typedef enum {
SCTP_CMD_T3_RTX_TIMERS_STOP, /* Stops T3-rtx pending timers */
SCTP_CMD_FORCE_PRIM_RETRAN, /* Forces retrans. over primary path. */
SCTP_CMD_SET_SK_ERR, /* Set sk_err */
+ SCTP_CMD_ASSOC_CHANGE, /* generate and send assoc_change event */
+ SCTP_CMD_ADAPTATION_IND, /* generate and send adaptation event */
SCTP_CMD_LAST
} sctp_verb_t;
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 7b4fff9..5e81984 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1857,6 +1857,7 @@ int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *,
int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
struct sctp_cookie*,
gfp_t gfp);
+int sctp_assoc_set_id(struct sctp_association *, gfp_t);
int sctp_cmp_addr_exact(const union sctp_addr *ss1,
const union sctp_addr *ss2);
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index db73ef9..df94e3c 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -1103,6 +1103,13 @@ void sctp_assoc_update(struct sctp_association *asoc,
asoc->ssnmap = new->ssnmap;
new->ssnmap = NULL;
}
+
+ if (!asoc->assoc_id) {
+ /* get a new association id since we don't have one
+ * yet.
+ */
+ sctp_assoc_set_id(asoc, GFP_ATOMIC);
+ }
}
}
@@ -1375,3 +1382,25 @@ out:
sctp_read_unlock(&asoc->base.addr_lock);
return found;
}
+
+/* Set an association id for a given association */
+int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
+{
+ int assoc_id;
+ int error = 0;
+retry:
+ if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
+ return -ENOMEM;
+
+ spin_lock_bh(&sctp_assocs_id_lock);
+ error = idr_get_new_above(&sctp_assocs_id, (void *)asoc,
+ 1, &assoc_id);
+ spin_unlock_bh(&sctp_assocs_id_lock);
+ if (error == -EAGAIN)
+ goto retry;
+ else if (error)
+ return error;
+
+ asoc->assoc_id = (sctp_assoc_t) assoc_id;
+ return error;
+}
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index be783a3..8d18f57 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1939,7 +1939,6 @@ int sctp_process_init(struct sctp_association *asoc, sctp_cid_t cid,
* association.
*/
if (!asoc->temp) {
- int assoc_id;
int error;
asoc->ssnmap = sctp_ssnmap_new(asoc->c.sinit_max_instreams,
@@ -1947,19 +1946,9 @@ int sctp_process_init(struct sctp_association *asoc, sctp_cid_t cid,
if (!asoc->ssnmap)
goto clean_up;
- retry:
- if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
+ error = sctp_assoc_set_id(asoc, gfp);
+ if (error)
goto clean_up;
- spin_lock_bh(&sctp_assocs_id_lock);
- error = idr_get_new_above(&sctp_assocs_id, (void *)asoc, 1,
- &assoc_id);
- spin_unlock_bh(&sctp_assocs_id_lock);
- if (error == -EAGAIN)
- goto retry;
- else if (error)
- goto clean_up;
-
- asoc->assoc_id = (sctp_assoc_t) assoc_id;
}
/* ADDIP Section 4.1 ASCONF Chunk Procedures
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index b37a7ad..d9fad4f 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -862,6 +862,33 @@ static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error)
sk->sk_err = error;
}
+/* Helper function to generate an association change event */
+static void sctp_cmd_assoc_change(sctp_cmd_seq_t *commands,
+ struct sctp_association *asoc,
+ u8 state)
+{
+ struct sctp_ulpevent *ev;
+
+ ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0,
+ asoc->c.sinit_num_ostreams,
+ asoc->c.sinit_max_instreams,
+ NULL, GFP_ATOMIC);
+ if (ev)
+ sctp_ulpq_tail_event(&asoc->ulpq, ev);
+}
+
+/* Helper function to generate an adaptation indication event */
+static void sctp_cmd_adaptation_ind(sctp_cmd_seq_t *commands,
+ struct sctp_association *asoc)
+{
+ struct sctp_ulpevent *ev;
+
+ ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
+
+ if (ev)
+ sctp_ulpq_tail_event(&asoc->ulpq, ev);
+}
+
/* These three macros allow us to pull the debugging code out of the
* main flow of sctp_do_sm() to keep attention focused on the real
* functionality there.
@@ -1485,6 +1512,14 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
case SCTP_CMD_SET_SK_ERR:
sctp_cmd_set_sk_err(asoc, cmd->obj.error);
break;
+ case SCTP_CMD_ASSOC_CHANGE:
+ sctp_cmd_assoc_change(commands, asoc,
+ cmd->obj.u8);
+ break;
+ case SCTP_CMD_ADAPTATION_IND:
+ sctp_cmd_adaptation_ind(commands, asoc);
+ break;
+
default:
printk(KERN_WARNING "Impossible command: %u, %p\n",
cmd->verb, cmd->obj.ptr);
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 9e28a5d..f02ce3d 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1656,7 +1656,6 @@ static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
struct sctp_association *new_asoc)
{
sctp_init_chunk_t *peer_init;
- struct sctp_ulpevent *ev;
struct sctp_chunk *repl;
/* new_asoc is a brand-new association, so these are not yet
@@ -1687,34 +1686,28 @@ static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep,
* D) IMPLEMENTATION NOTE: An implementation may choose to
* send the Communication Up notification to the SCTP user
* upon reception of a valid COOKIE ECHO chunk.
+ *
+ * Sadly, this needs to be implemented as a side-effect, because
+ * we are not guaranteed to have set the association id of the real
+ * association and so these notifications need to be delayed until
+ * the association id is allocated.
*/
- ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 0,
- new_asoc->c.sinit_num_ostreams,
- new_asoc->c.sinit_max_instreams,
- NULL, GFP_ATOMIC);
- if (!ev)
- goto nomem_ev;
- sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
+ sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
/* Sockets API Draft Section 5.3.1.6
* When a peer sends a Adaptation Layer Indication parameter , SCTP
* delivers this notification to inform the application that of the
* peers requested adaptation layer.
+ *
+ * This also needs to be done as a side effect for the same reason as
+ * above.
*/
- if (asoc->peer.adaptation_ind) {
- ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
- if (!ev)
- goto nomem_ev;
-
- sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
- SCTP_ULPEVENT(ev));
- }
+ if (asoc->peer.adaptation_ind)
+ sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
return SCTP_DISPOSITION_CONSUME;
-nomem_ev:
- sctp_chunk_free(repl);
nomem:
return SCTP_DISPOSITION_NOMEM;
}
--
1.5.0.3.438.gc49b2
-
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