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-rw-r--r--net/dccp/dccp.h46
1 files changed, 36 insertions, 10 deletions
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 3ccef1b70fee..3eb264b60823 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -153,18 +153,27 @@ static inline u64 max48(const u64 seq1, const u64 seq2)
}
/**
- * dccp_loss_free - Evaluates condition for data loss from RFC 4340, 7.7.1
- * @s1: start sequence number
- * @s2: end sequence number
+ * dccp_loss_count - Approximate the number of lost data packets in a burst loss
+ * @s1: last known sequence number before the loss ('hole')
+ * @s2: first sequence number seen after the 'hole'
* @ndp: NDP count on packet with sequence number @s2
- * Returns true if the sequence range s1...s2 has no data loss.
*/
-static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
+static inline u64 dccp_loss_count(const u64 s1, const u64 s2, const u64 ndp)
{
s64 delta = dccp_delta_seqno(s1, s2);
WARN_ON(delta < 0);
- return (u64)delta <= ndp + 1;
+ delta -= ndp + 1;
+
+ return delta > 0 ? delta : 0;
+}
+
+/**
+ * dccp_loss_free - Evaluate condition for data loss from RFC 4340, 7.7.1
+ */
+static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
+{
+ return dccp_loss_count(s1, s2, ndp) == 0;
}
enum {
@@ -246,7 +255,6 @@ static inline void dccp_clear_xmit_timers(struct sock *sk)
extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
extern const char *dccp_packet_name(const int type);
-extern const char *dccp_state_name(const int state);
extern void dccp_set_state(struct sock *sk, const int state);
extern void dccp_done(struct sock *sk);
@@ -415,6 +423,23 @@ static inline void dccp_update_gsr(struct sock *sk, u64 seq)
dp->dccps_gsr = seq;
/* Sequence validity window depends on remote Sequence Window (7.5.1) */
dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4);
+ /*
+ * Adjust SWL so that it is not below ISR. In contrast to RFC 4340,
+ * 7.5.1 we perform this check beyond the initial handshake: W/W' are
+ * always > 32, so for the first W/W' packets in the lifetime of a
+ * connection we always have to adjust SWL.
+ * A second reason why we are doing this is that the window depends on
+ * the feature-remote value of Sequence Window: nothing stops the peer
+ * from updating this value while we are busy adjusting SWL for the
+ * first W packets (we would have to count from scratch again then).
+ * Therefore it is safer to always make sure that the Sequence Window
+ * is not artificially extended by a peer who grows SWL downwards by
+ * continually updating the feature-remote Sequence-Window.
+ * If sequence numbers wrap it is bad luck. But that will take a while
+ * (48 bit), and this measure prevents Sequence-number attacks.
+ */
+ if (before48(dp->dccps_swl, dp->dccps_isr))
+ dp->dccps_swl = dp->dccps_isr;
dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4);
}
@@ -425,14 +450,16 @@ static inline void dccp_update_gss(struct sock *sk, u64 seq)
dp->dccps_gss = seq;
/* Ack validity window depends on local Sequence Window value (7.5.1) */
dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win);
+ /* Adjust AWL so that it is not below ISS - see comment above for SWL */
+ if (before48(dp->dccps_awl, dp->dccps_iss))
+ dp->dccps_awl = dp->dccps_iss;
dp->dccps_awh = dp->dccps_gss;
}
static inline int dccp_ack_pending(const struct sock *sk)
{
const struct dccp_sock *dp = dccp_sk(sk);
- return dp->dccps_timestamp_echo != 0 ||
- (dp->dccps_hc_rx_ackvec != NULL &&
+ return (dp->dccps_hc_rx_ackvec != NULL &&
dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
inet_csk_ack_scheduled(sk);
}
@@ -449,7 +476,6 @@ extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
extern int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed);
extern u32 dccp_timestamp(void);
extern void dccp_timestamping_init(void);
-extern int dccp_insert_option_timestamp(struct sk_buff *skb);
extern int dccp_insert_option(struct sk_buff *skb, unsigned char option,
const void *value, unsigned char len);