X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=net%2Fdccp%2Finput.c;h=3560a2a875a05561f2d0b353cb62b6b58095e8b4;hb=4800be295c34268fd3211d49828bfaa6bf62867f;hp=78b043c458bf95ac78aab62526408e09a72f8f00;hpb=cb2ebc59ff52cee770cfd6ba5f23a6cc3c214648;p=linux-2.6 diff --git a/net/dccp/input.c b/net/dccp/input.c index 78b043c458..3560a2a875 100644 --- a/net/dccp/input.c +++ b/net/dccp/input.c @@ -19,6 +19,9 @@ #include "ccid.h" #include "dccp.h" +/* 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 void dccp_fin(struct sock *sk, struct sk_buff *skb) { sk->sk_shutdown |= RCV_SHUTDOWN; @@ -68,7 +71,8 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) { const struct dccp_hdr *dh = dccp_hdr(skb); struct dccp_sock *dp = dccp_sk(sk); - u64 lswl, lawl; + u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq, + ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; /* * Step 5: Prepare sequence numbers for Sync @@ -84,10 +88,9 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) */ if (dh->dccph_type == DCCP_PKT_SYNC || dh->dccph_type == DCCP_PKT_SYNCACK) { - if (between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, - dp->dccps_awl, dp->dccps_awh) && - !before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_swl)) - dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq); + if (between48(ackno, dp->dccps_awl, dp->dccps_awh) && + dccp_delta_seqno(dp->dccps_swl, seqno) >= 0) + dccp_update_gsr(sk, seqno); else return -1; } @@ -102,9 +105,6 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) * Update S.GSR, S.SWL, S.SWH * If P.type != Sync, * Update S.GAR - * Otherwise, - * Send Sync packet acknowledging P.seqno - * Drop packet and return */ lswl = dp->dccps_swl; lawl = dp->dccps_awl; @@ -112,35 +112,52 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) if (dh->dccph_type == DCCP_PKT_CLOSEREQ || dh->dccph_type == DCCP_PKT_CLOSE || dh->dccph_type == DCCP_PKT_RESET) { - lswl = dp->dccps_gsr; - dccp_inc_seqno(&lswl); + lswl = ADD48(dp->dccps_gsr, 1); lawl = dp->dccps_gar; } - if (between48(DCCP_SKB_CB(skb)->dccpd_seq, lswl, dp->dccps_swh) && - (DCCP_SKB_CB(skb)->dccpd_ack_seq == DCCP_PKT_WITHOUT_ACK_SEQ || - between48(DCCP_SKB_CB(skb)->dccpd_ack_seq, - lawl, dp->dccps_awh))) { - dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq); + if (between48(seqno, lswl, dp->dccps_swh) && + (ackno == DCCP_PKT_WITHOUT_ACK_SEQ || + between48(ackno, lawl, dp->dccps_awh))) { + dccp_update_gsr(sk, seqno); if (dh->dccph_type != DCCP_PKT_SYNC && - (DCCP_SKB_CB(skb)->dccpd_ack_seq != - DCCP_PKT_WITHOUT_ACK_SEQ)) - dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq; + (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), " "sending SYNC...\n", dccp_packet_name(dh->dccph_type), - (unsigned long long) lswl, - (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq, + (unsigned long long) lswl, (unsigned long long) seqno, (unsigned long long) dp->dccps_swh, - (DCCP_SKB_CB(skb)->dccpd_ack_seq == - DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" : "exists", - (unsigned long long) lawl, - (unsigned long long) DCCP_SKB_CB(skb)->dccpd_ack_seq, + (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist" + : "exists", + (unsigned long long) lawl, (unsigned long long) ackno, (unsigned long long) dp->dccps_awh); - dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); + + dp->dccps_rate_last = now; + + if (dh->dccph_type == DCCP_PKT_RESET) + seqno = dp->dccps_gsr; + dccp_send_sync(sk, seqno, DCCP_PKT_SYNC); return -1; } @@ -203,7 +220,8 @@ static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb, if (dp->dccps_role != DCCP_ROLE_CLIENT) goto send_sync; check_seq: - if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) { + if (dccp_delta_seqno(dp->dccps_osr, + DCCP_SKB_CB(skb)->dccpd_seq) >= 0) { send_sync: dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC); @@ -278,6 +296,7 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk, if (dh->dccph_type == DCCP_PKT_RESPONSE) { const struct inet_connection_sock *icsk = inet_csk(sk); struct dccp_sock *dp = dccp_sk(sk); + long tstamp = dccp_timestamp(); /* Stop the REQUEST timer */ inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); @@ -298,6 +317,11 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk, if (dccp_parse_options(sk, skb)) goto out_invalid_packet; + /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */ + if (likely(dp->dccps_options_received.dccpor_timestamp_echo)) + dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp - + dp->dccps_options_received.dccpor_timestamp_echo)); + if (dccp_msk(sk)->dccpms_send_ack_vector && dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk, DCCP_SKB_CB(skb)->dccpd_seq, @@ -530,11 +554,6 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, return 0; } - if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) { - dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK); - goto discard; - } - switch (sk->sk_state) { case DCCP_CLOSED: dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION; @@ -565,6 +584,9 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, sk_wake_async(sk, 0, POLL_OUT); break; } + } else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) { + dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK); + goto discard; } if (!queued) { @@ -575,3 +597,28 @@ discard: } EXPORT_SYMBOL_GPL(dccp_rcv_state_process); + +/** + * dccp_sample_rtt - Validate and finalise computation of RTT sample + * @delta: number of microseconds between packet and acknowledgment + * The routine is kept generic to work in different contexts. It should be + * called immediately when the ACK used for the RTT sample arrives. + */ +u32 dccp_sample_rtt(struct sock *sk, long delta) +{ + /* dccpor_elapsed_time is either zeroed out or set and > 0 */ + delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10; + + if (unlikely(delta <= 0)) { + DCCP_WARN("unusable RTT sample %ld, using min\n", delta); + return DCCP_SANE_RTT_MIN; + } + if (unlikely(delta > DCCP_SANE_RTT_MAX)) { + DCCP_WARN("RTT sample %ld too large, using max\n", delta); + return DCCP_SANE_RTT_MAX; + } + + return delta; +} + +EXPORT_SYMBOL_GPL(dccp_sample_rtt);