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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>
This commit is contained in:
Gerrit Renker 2008-09-04 07:30:19 +02:00
parent e70cacb90d
commit c49b22729f
1 changed files with 26 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
net/dccp/input.c
View File

@ -421,8 +421,13 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk,
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 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk,
*/
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 @@ out_invalid_packet:
/* 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 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
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 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
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;