diff options
Diffstat (limited to 'net/dccp')
| -rw-r--r-- | net/dccp/dccp.h | 1 | ||||
| -rw-r--r-- | net/dccp/input.c | 29 | ||||
| -rw-r--r-- | net/dccp/proto.c | 1 | ||||
| -rw-r--r-- | net/dccp/sysctl.c | 10 |
4 files changed, 32 insertions, 9 deletions
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h index e28220183208..a602d9212c64 100644 --- a/net/dccp/dccp.h +++ b/net/dccp/dccp.h @@ -92,6 +92,7 @@ extern int sysctl_dccp_feat_ack_ratio; extern int sysctl_dccp_feat_send_ack_vector; extern int sysctl_dccp_feat_send_ndp_count; extern int sysctl_dccp_tx_qlen; +extern int sysctl_dccp_sync_ratelimit; /* * 48-bit sequence number arithmetic (signed and unsigned) diff --git a/net/dccp/input.c b/net/dccp/input.c index 86ad3ba0649a..19d7e1dbd87e 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); diff --git a/net/dccp/proto.c b/net/dccp/proto.c index 14ec1d21452c..604de8bfa068 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -219,6 +219,7 @@ int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized) sk->sk_write_space = dccp_write_space; icsk->icsk_sync_mss = dccp_sync_mss; dp->dccps_mss_cache = 536; + dp->dccps_rate_last = jiffies; dp->dccps_role = DCCP_ROLE_UNDEFINED; dp->dccps_service = DCCP_SERVICE_CODE_IS_ABSENT; dp->dccps_l_ack_ratio = dp->dccps_r_ack_ratio = 1; diff --git a/net/dccp/sysctl.c b/net/dccp/sysctl.c index 1260aabac5e1..9364b2fb4dbd 100644 --- a/net/dccp/sysctl.c +++ b/net/dccp/sysctl.c @@ -18,6 +18,9 @@ #error This file should not be compiled without CONFIG_SYSCTL defined #endif +/* rate-limit for syncs in reply to sequence-invalid packets; RFC 4340, 7.5.4 */ +int sysctl_dccp_sync_ratelimit __read_mostly = HZ / 8; + static struct ctl_table dccp_default_table[] = { { .procname = "seq_window", @@ -89,6 +92,13 @@ static struct ctl_table dccp_default_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "sync_ratelimit", + .data = &sysctl_dccp_sync_ratelimit, + .maxlen = sizeof(sysctl_dccp_sync_ratelimit), + .mode = 0644, + .proc_handler = proc_dointvec_ms_jiffies, + }, { .ctl_name = 0, } }; |