1 files changed, 30 insertions, 13 deletions

diff --git a/net/dccp/options.c b/net/dccp/options.c
index 5adeeed5e0d2..f06ffcfc8d71 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -54,7 +54,6 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
         struct dccp_sock *dp = dccp_sk(sk);
         const struct dccp_hdr *dh = dccp_hdr(skb);
         const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
-        u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
         unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
         unsigned char *opt_ptr = options;
         const unsigned char *opt_end = (unsigned char *)dh +
@@ -129,14 +128,6 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
                         if (rc)
                                 goto out_featneg_failed;
                         break;
-                case DCCPO_ACK_VECTOR_0:
-                case DCCPO_ACK_VECTOR_1:
-                        if (dccp_packet_without_ack(skb))   /* RFC 4340, 11.4 */
-                                break;
-                        if (dp->dccps_hc_rx_ackvec != NULL &&
-                            dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
-                                goto out_invalid_option;
-                        break;
                 case DCCPO_TIMESTAMP:
                         if (len != 4)
                                 goto out_invalid_option;
@@ -226,6 +217,16 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
                                                      pkt_type, opt, value, len))
                                 goto out_invalid_option;
                         break;
+                case DCCPO_ACK_VECTOR_0:
+                case DCCPO_ACK_VECTOR_1:
+                        if (dccp_packet_without_ack(skb))   /* RFC 4340, 11.4 */
+                                break;
+                        /*
+                         * Ack vectors are processed by the TX CCID if it is
+                         * interested. The RX CCID need not parse Ack Vectors,
+                         * since it is only interested in clearing old state.
+                         * Fall through.
+                         */
                 case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC:
                         if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
                                                      pkt_type, opt, value, len))
@@ -429,6 +430,7 @@ static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
 {
         struct dccp_sock *dp = dccp_sk(sk);
         struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
+        struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
         const u16 buflen = dccp_ackvec_buflen(av);
         /* Figure out how many options do we need to represent the ackvec */
         const u8 nr_opts = DIV_ROUND_UP(buflen, DCCP_SINGLE_OPT_MAXLEN);
@@ -437,10 +439,25 @@ static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
         const unsigned char *tail, *from;
         unsigned char *to;
 
-        if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
+        if (dcb->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
+                DCCP_WARN("Lacking space for %u bytes on %s packet\n", len,
+                          dccp_packet_name(dcb->dccpd_type));
                 return -1;
-
-        DCCP_SKB_CB(skb)->dccpd_opt_len += len;
+        }
+        /*
+         * Since Ack Vectors are variable-length, we can not always predict
+         * their size. To catch exception cases where the space is running out
+         * on the skb, a separate Sync is scheduled to carry the Ack Vector.
+         */
+        if (len > DCCPAV_MIN_OPTLEN &&
+            len + dcb->dccpd_opt_len + skb->len > dp->dccps_mss_cache) {
+                DCCP_WARN("No space left for Ack Vector (%u) on skb (%u+%u), "
+                          "MPS=%u ==> reduce payload size?\n", len, skb->len,
+                          dcb->dccpd_opt_len, dp->dccps_mss_cache);
+                dp->dccps_sync_scheduled = 1;
+                return 0;
+        }
+        dcb->dccpd_opt_len += len;
 
         to   = skb_push(skb, len);
         len  = buflen;
@@ -481,7 +498,7 @@ static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
         /*
          * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340.
          */
-        if (dccp_ackvec_update_records(av, DCCP_SKB_CB(skb)->dccpd_seq, nonce))
+        if (dccp_ackvec_update_records(av, dcb->dccpd_seq, nonce))
                 return -ENOBUFS;
         return 0;
 }