dccp: Integration of dynamic feature activation - part 3 (client side)
This integrates feature-activation in the client, with these details:
1. When dccp_parse_options() fails, the reset code is already set, request_sent
_state_process() currently overrides this with `Packet Error', which is not
intended - so changed to use the reset code set in dccp_parse_options();
2. There was a FIXME to change the error code when dccp_ackvec_add() fails.
I have looked this up and found that:
* the check whether ackno < ISN is already made earlier,
* this Response is likely the 1st packet with an Ackno that the client gets,
* so when dccp_ackvec_add() fails, the reason is likely not a packet error.
3. When feature negotiation fails, the socket should be marked as not usable,
so that the application is notified that an error occurs. This is achieved
by a new label, which uses an error code of `Aborted' and which sets the
socket state to CLOSED, as well as sk_err.
4. Avoids parsing the Ack twice in Respond state by not doing option processing
again in dccp_rcv_respond_partopen_state_process (as option processing has
already been done on the request_sock in dccp_check_req).
Since this addresses congestion-control initialisation, a corresponding
FIXME has been removed.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
diff --git a/net/dccp/input.c b/net/dccp/input.c
index 3070015..0672b7e 100644
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -421,8 +421,13 @@
goto out_invalid_packet;
}
+ /*
+ * If option processing (Step 8) failed, return 1 here so that
+ * dccp_v4_do_rcv() sends a Reset. The Reset code depends on
+ * the option type and is set in dccp_parse_options().
+ */
if (dccp_parse_options(sk, NULL, skb))
- goto out_invalid_packet;
+ return 1;
/* Obtain usec RTT sample from SYN exchange (used by CCID 3) */
if (likely(dp->dccps_options_received.dccpor_timestamp_echo))
@@ -475,6 +480,15 @@
*/
dccp_set_state(sk, DCCP_PARTOPEN);
+ /*
+ * If feature negotiation was successful, activate features now;
+ * an activation failure means that this host could not activate
+ * one ore more features (e.g. insufficient memory), which would
+ * leave at least one feature in an undefined state.
+ */
+ if (dccp_feat_activate_values(sk, &dp->dccps_featneg))
+ goto unable_to_proceed;
+
/* Make sure socket is routed, for correct metrics. */
icsk->icsk_af_ops->rebuild_header(sk);
@@ -509,6 +523,16 @@
/* dccp_v4_do_rcv will send a reset */
DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
return 1;
+
+unable_to_proceed:
+ DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_ABORTED;
+ /*
+ * We mark this socket as no longer usable, so that the loop in
+ * dccp_sendmsg() terminates and the application gets notified.
+ */
+ dccp_set_state(sk, DCCP_CLOSED);
+ sk->sk_err = ECOMM;
+ return 1;
}
static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
@@ -600,7 +624,7 @@
return 1;
}
- if (sk->sk_state != DCCP_REQUESTING) {
+ if (sk->sk_state != DCCP_REQUESTING && sk->sk_state != DCCP_RESPOND) {
if (dccp_check_seqno(sk, skb))
goto discard;
@@ -665,8 +689,6 @@
return 1;
case DCCP_REQUESTING:
- /* FIXME: do congestion control initialization */
-
queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
if (queued >= 0)
return queued;