struct inet_connection_sock *icsk = inet_csk(sk);
struct dccp_sock *dp = dccp_sk(sk);
u32 ccmps = dccp_determine_ccmps(dp);
- int cur_mps = ccmps ? min(pmtu, ccmps) : pmtu;
+ u32 cur_mps = ccmps ? min(pmtu, ccmps) : pmtu;
/* Account for header lengths and IPv4/v6 option overhead */
cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len +
sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext));
/*
- * FIXME: this should come from the CCID infrastructure, where, say,
- * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
- * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
- * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
- * make it a multiple of 4
+ * Leave enough headroom for common DCCP header options.
+ * This only considers options which may appear on DCCP-Data packets, as
+ * per table 3 in RFC 4340, 5.8. When running out of space for other
+ * options (eg. Ack Vector which can take up to 255 bytes), it is better
+ * to schedule a separate Ack. Thus we leave headroom for the following:
+ * - 1 byte for Slow Receiver (11.6)
+ * - 6 bytes for Timestamp (13.1)
+ * - 10 bytes for Timestamp Echo (13.3)
+ * - 8 bytes for NDP count (7.7, when activated)
+ * - 6 bytes for Data Checksum (9.3)
+ * - %DCCPAV_MIN_OPTLEN bytes for Ack Vector size (11.4, when enabled)
*/
-
- cur_mps -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
+ cur_mps -= roundup(1 + 6 + 10 + dp->dccps_send_ndp_count * 8 + 6 +
+ (dp->dccps_hc_rx_ackvec ? DCCPAV_MIN_OPTLEN : 0), 4);
/* And store cached results */
icsk->icsk_pmtu_cookie = pmtu;
DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
- if (dccp_insert_options_rsk(dreq, skb)) {
- kfree_skb(skb);
- return NULL;
- }
+ /* Resolve feature dependencies resulting from choice of CCID */
+ if (dccp_feat_server_ccid_dependencies(dreq))
+ goto response_failed;
+
+ if (dccp_insert_options_rsk(dreq, skb))
+ goto response_failed;
/* Build and checksum header */
dh = dccp_zeroed_hdr(skb, dccp_header_size);
inet_rsk(req)->acked = 1;
DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
return skb;
+response_failed:
+ kfree_skb(skb);
+ return NULL;
}
EXPORT_SYMBOL_GPL(dccp_make_response);
struct sk_buff *skb;
struct inet_connection_sock *icsk = inet_csk(sk);
+ /* do not connect if feature negotiation setup fails */
+ if (dccp_feat_finalise_settings(dccp_sk(sk)))
+ return -EPROTO;
+
dccp_connect_init(sk);
skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);