diff options
Diffstat (limited to 'net/dccp/input.c')
| -rw-r--r-- | net/dccp/input.c | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/net/dccp/input.c b/net/dccp/input.c index 86ad3ba0649..19d7e1dbd87 100644 --- a/net/dccp/input.c +++ b/net/dccp/input.c @@ -122,6 +122,23 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) (ackno != DCCP_PKT_WITHOUT_ACK_SEQ)) dp->dccps_gar = ackno; } else { + unsigned long now = jiffies; + /* + * Step 6: Check sequence numbers + * Otherwise, + * If P.type == Reset, + * Send Sync packet acknowledging S.GSR + * Otherwise, + * Send Sync packet acknowledging P.seqno + * Drop packet and return + * + * These Syncs are rate-limited as per RFC 4340, 7.5.4: + * at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second. + */ + if (time_before(now, (dp->dccps_rate_last + + sysctl_dccp_sync_ratelimit))) + return 0; + DCCP_WARN("DCCP: Step 6 failed for %s packet, " "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and " "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), " @@ -132,15 +149,9 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) : "exists", (unsigned long long) lawl, (unsigned long long) ackno, (unsigned long long) dp->dccps_awh); - /* - * Step 6: Check sequence numbers - * Otherwise, - * If P.type == Reset, - * Send Sync packet acknowledging S.GSR - * Otherwise, - * Send Sync packet acknowledging P.seqno - * Drop packet and return - */ + + dp->dccps_rate_last = now; + if (dh->dccph_type == DCCP_PKT_RESET) seqno = dp->dccps_gsr; dccp_send_sync(sk, seqno, DCCP_PKT_SYNC); |