dccp ccid-2: Phase out the use of boolean Ack Vector sysctl

This removes the use of the sysctl and the minisock variable for the Send Ack
Vector feature, as it now is handled fully dynamically via feature negotiation
(i.e. when CCID-2 is enabled, Ack Vectors are automatically enabled as per
 RFC 4341, 4.).

Using a sysctl in parallel to this implementation would open the door to
crashes, since much of the code relies on tests of the boolean minisock /
sysctl variable. Thus, this patch replaces all tests of type

	if (dccp_msk(sk)->dccpms_send_ack_vector)
		/* ... */
with
	if (dp->dccps_hc_rx_ackvec != NULL)
		/* ... */

The dccps_hc_rx_ackvec is allocated by the dccp_hdlr_ackvec() when feature
negotiation concluded that Ack Vectors are to be used on the half-connection.
Otherwise, it is NULL (due to dccp_init_sock/dccp_create_openreq_child),
so that the test is a valid one.

The activation handler for Ack Vectors is called as soon as the feature
negotiation has concluded at the
 * server when the Ack marking the transition RESPOND => OPEN arrives;
 * client after it has sent its ACK, marking the transition REQUEST => PARTOPEN.

Adding the sequence number of the Response packet to the Ack Vector has been
removed, since
 (a) connection establishment implies that the Response has been received;
 (b) the CCIDs only look at packets received in the (PART)OPEN state, i.e.
     this entry will always be ignored;
 (c) it can not be used for anything useful - to detect loss for instance, only
     packets received after the loss can serve as pseudo-dupacks.

There was a FIXME to change the error code when dccp_ackvec_add() fails.
I removed this after finding out that:
 * the check whether ackno < ISN is already made earlier,
 * this Response is likely the 1st packet with an Ackno that the client gets,
 * so when dccp_ackvec_add() fails, the reason is likely not a packet error.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt
index 1403745ab406bce7a9c8e56d89c40761f39803ba..7a3bb1abb8304a1fe7222e354e43164a7a7635bb 100644 (file)
--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -133,9 +133,6 @@ retries2
        importance for retransmitted acknowledgments and feature negotiation,
        data packets are never retransmitted. Analogue of tcp_retries2.
 
-send_ackvec = 1
-       Whether or not to send Ack Vector options (sec. 11.5).
-
 tx_ccid = 2
        Default CCID for the sender-receiver half-connection. Depending on the
        choice of CCID, the Send Ack Vector feature is enabled automatically.

diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index 60e94438eadd4d3c82b7463750381b95c9ce2281..61734e27abb7b6fc5e0c54d018c8969381a23c86 100644 (file)
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -360,7 +360,6 @@ static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
 #define DCCPF_INITIAL_SEQUENCE_WINDOW          100
 #define DCCPF_INITIAL_ACK_RATIO                        2
 #define DCCPF_INITIAL_CCID                     DCCPC_CCID2
-#define DCCPF_INITIAL_SEND_ACK_VECTOR          1
 /* FIXME: for now we're default to 1 but it should really be 0 */
 #define DCCPF_INITIAL_SEND_NDP_COUNT           1
 
@@ -370,13 +369,11 @@ static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
   * Will be used to pass the state from dccp_request_sock to dccp_sock.
   *
   * @dccpms_sequence_window - Sequence Window Feature (section 7.5.2)
-  * @dccpms_send_ack_vector - Send Ack Vector Feature (section 11.5)
   * @dccpms_pending - List of features being negotiated
   * @dccpms_conf -
   */
 struct dccp_minisock {
        __u64                   dccpms_sequence_window;
-       __u8                    dccpms_send_ack_vector;
        struct list_head        dccpms_pending;
        struct list_head        dccpms_conf;
 };

diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index e0759d098b9a6716033ec850168ad7f7f1d0257d..0bc4c9a02e1964d3f6e0c5431b0a4d968115739a 100644 (file)
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -98,7 +98,6 @@ extern int  sysctl_dccp_retries2;
 extern int  sysctl_dccp_feat_sequence_window;
 extern int  sysctl_dccp_feat_rx_ccid;
 extern int  sysctl_dccp_feat_tx_ccid;
-extern int  sysctl_dccp_feat_send_ack_vector;
 extern int  sysctl_dccp_tx_qlen;
 extern int  sysctl_dccp_sync_ratelimit;
 
@@ -434,7 +433,7 @@ static inline int dccp_ack_pending(const struct sock *sk)
        const struct dccp_sock *dp = dccp_sk(sk);
        return dp->dccps_timestamp_echo != 0 ||
 #ifdef CONFIG_IP_DCCP_ACKVEC
-              (dccp_msk(sk)->dccpms_send_ack_vector &&
+              (dp->dccps_hc_rx_ackvec != NULL &&
                dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
 #endif
               inet_csk_ack_scheduled(sk);

diff --git a/net/dccp/diag.c b/net/dccp/diag.c
index d1e100395efbadd110e7b17775ed01306f3c430c..652a1b67f727dc6fce90eeff772e70d53c209c47 100644 (file)
--- a/net/dccp/diag.c
+++ b/net/dccp/diag.c
@@ -29,7 +29,7 @@ static void dccp_get_info(struct sock *sk, struct tcp_info *info)
        info->tcpi_backoff      = icsk->icsk_backoff;
        info->tcpi_pmtu         = icsk->icsk_pmtu_cookie;
 
-       if (dccp_msk(sk)->dccpms_send_ack_vector)
+       if (dp->dccps_hc_rx_ackvec != NULL)
                info->tcpi_options |= TCPI_OPT_SACK;
 
        ccid_hc_rx_get_info(dp->dccps_hc_rx_ccid, sk, info);

diff --git a/net/dccp/input.c b/net/dccp/input.c
index 0672b7e1763ef31f15d142cd52073a6d25ba0870..5eb443f656c19ea115114379703c72bc31e79fb0 100644 (file)
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -163,7 +163,7 @@ static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
 {
        struct dccp_sock *dp = dccp_sk(sk);
 
-       if (dccp_msk(sk)->dccpms_send_ack_vector)
+       if (dp->dccps_hc_rx_ackvec != NULL)
                dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
                                            DCCP_SKB_CB(skb)->dccpd_ack_seq);
 }
@@ -375,7 +375,7 @@ int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
        if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
                dccp_event_ack_recv(sk, skb);
 
-       if (dccp_msk(sk)->dccpms_send_ack_vector &&
+       if (dp->dccps_hc_rx_ackvec != NULL &&
            dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
                            DCCP_SKB_CB(skb)->dccpd_seq,
                            DCCP_ACKVEC_STATE_RECEIVED))
@@ -434,12 +434,6 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk,
                        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,
-                                   DCCP_ACKVEC_STATE_RECEIVED))
-                       goto out_invalid_packet; /* FIXME: change error code */
-
                /* Stop the REQUEST timer */
                inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
                WARN_ON(sk->sk_send_head == NULL);
@@ -637,7 +631,7 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
                        dccp_event_ack_recv(sk, skb);
 
-               if (dccp_msk(sk)->dccpms_send_ack_vector &&
+               if (dp->dccps_hc_rx_ackvec != NULL &&
                    dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
                                    DCCP_SKB_CB(skb)->dccpd_seq,
                                    DCCP_ACKVEC_STATE_RECEIVED))

diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c
index 02b14812464a236bb4e6dab4824254defe82e506..6821ae33dd37a02600dc80b4ba7f8f8452c6185a 100644 (file)
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
@@ -45,7 +45,6 @@ EXPORT_SYMBOL_GPL(dccp_death_row);
 void dccp_minisock_init(struct dccp_minisock *dmsk)
 {
        dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window;
-       dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector;
 }
 
 void dccp_time_wait(struct sock *sk, int state, int timeo)

diff --git a/net/dccp/options.c b/net/dccp/options.c
index e9d674874b4e823a28c5c5a2579978d3cfddf16e..7b1165c21f5173a40c9511f934ccc5dcc02cc896 100644 (file)
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -26,7 +26,6 @@
 int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW;
 int sysctl_dccp_feat_rx_ccid         = DCCPF_INITIAL_CCID;
 int sysctl_dccp_feat_tx_ccid         = DCCPF_INITIAL_CCID;
-int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR;
 
 u64 dccp_decode_value_var(const u8 *bf, const u8 len)
 {
@@ -145,8 +144,7 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
                case DCCPO_ACK_VECTOR_1:
                        if (dccp_packet_without_ack(skb))   /* RFC 4340, 11.4 */
                                break;
-
-                       if (dccp_msk(sk)->dccpms_send_ack_vector &&
+                       if (dp->dccps_hc_rx_ackvec != NULL &&
                            dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
                                goto out_invalid_option;
                        break;
@@ -526,7 +524,6 @@ static void dccp_insert_option_padding(struct sk_buff *skb)
 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
 {
        struct dccp_sock *dp = dccp_sk(sk);
-       struct dccp_minisock *dmsk = dccp_msk(sk);
 
        DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
 
@@ -547,7 +544,7 @@ int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
                        if (dccp_insert_option_timestamp(sk, skb))
                                return -1;
 
-               } else if (dmsk->dccpms_send_ack_vector &&
+               } else if (dp->dccps_hc_rx_ackvec != NULL &&
                           dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
                           dccp_insert_option_ackvec(sk, skb)) {
                                return -1;

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 0941f8fe1675bb5160a5bbaf91d3accc7f3347be..d5c2bacb713c6055ffb9a3ca9cb8975ebb907a9a 100644 (file)
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -201,7 +201,6 @@ EXPORT_SYMBOL_GPL(dccp_init_sock);
 void dccp_destroy_sock(struct sock *sk)
 {
        struct dccp_sock *dp = dccp_sk(sk);
-       struct dccp_minisock *dmsk = dccp_msk(sk);
 
        /*
         * DCCP doesn't use sk_write_queue, just sk_send_head
@@ -219,7 +218,7 @@ void dccp_destroy_sock(struct sock *sk)
        kfree(dp->dccps_service_list);
        dp->dccps_service_list = NULL;
 
-       if (dmsk->dccpms_send_ack_vector) {
+       if (dp->dccps_hc_rx_ackvec != NULL) {
                dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
                dp->dccps_hc_rx_ackvec = NULL;
        }

diff --git a/net/dccp/sysctl.c b/net/dccp/sysctl.c
index 587c12f915c1344d7a539703fb2485ec72ce0212..018e210875e168141a2aca941ab11ca7daaca9ef 100644 (file)
--- a/net/dccp/sysctl.c
+++ b/net/dccp/sysctl.c
@@ -40,13 +40,6 @@ static struct ctl_table dccp_default_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
-       {
-               .procname       = "send_ackvec",
-               .data           = &sysctl_dccp_feat_send_ack_vector,
-               .maxlen         = sizeof(sysctl_dccp_feat_send_ack_vector),
-               .mode           = 0644,
-               .proc_handler   = proc_dointvec,
-       },
        {
                .procname       = "request_retries",
                .data           = &sysctl_dccp_request_retries,