[DCCP]: Integration of dynamic feature activation - part 3 (client side) This integrates feature-activation in the client, the following details needed to be addressed: 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 first packet with an Ack number that the client gets, * so when dccp_ackvec_add() fails, the reason is likely not due to a packet error. There is another problem: when a connecting client sends a Reset in state REQUEST, the loop in dccp_sendmsg(), which waits in sk_stream_wait_connect() for the transition to PARTOPEN, does not (and will not) happen. The same problem also occurs if the feature negotiation during connection setup fails. Thus I have lumped this case together with the following: 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. Since this addresses congestion-control initialisation, a corresponding FIXME has been removed. Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx> --- net/dccp/input.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) --- a/net/dccp/input.c +++ b/net/dccp/input.c @@ -382,8 +382,13 @@ static int dccp_rcv_request_sent_state_p 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)) @@ -394,7 +399,7 @@ static int dccp_rcv_request_sent_state_p dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_ACKVEC_STATE_RECEIVED)) - goto out_invalid_packet; /* FIXME: change error code */ + goto unable_to_proceed; dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq; dccp_update_gsr(sk, dp->dccps_isr); @@ -456,6 +461,13 @@ static int dccp_rcv_request_sent_state_p __kfree_skb(skb); return 0; } + /* + * If feature negotiation throws an error, we can not proceed + * (one or more feature values are undefined), so we send a + * Reset. Otherwise, the Ack will clear any pending Confirms. + */ + if (dccp_feat_activate_values(sk, &dp->dccps_featneg)) + goto unable_to_proceed; dccp_send_ack(sk); return -1; } @@ -464,6 +476,16 @@ 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, @@ -621,8 +643,6 @@ int dccp_rcv_state_process(struct sock * 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; - To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
