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Commit 07d93967 authored by Vlad Yasevich's avatar Vlad Yasevich Committed by David S. Miller
Browse files

[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@motorola.com>, flow looks like this:
A				B
---- INIT------->  (lost)
	    <---------INIT------
---- INIT-ACK--->
	    <------ Cookie ECHO

When the Cookie Echo is received, we end up trying to update the
association that was created on A as a result of the (lost) INIT,
but that association doesn't have the ID set yet.

Signed-off-by: default avatarVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 827bf122

include/net/sctp/command.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

include/net/sctp/structs.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

net/sctp/associola.c

+29 −0
Original line number Diff line number Diff line
@@ -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;

}

net/sctp/sm_make_chunk.c

+2 −13
Original line number Diff line number Diff line
@@ -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

net/sctp/sm_sideeffect.c

+35 −0
Original line number Diff line number Diff line
@@ -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);