2 files changed, 204 insertions, 10 deletions

diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 2e2a6f229eaf..1baed789bcc2 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -445,6 +445,7 @@ extern int  dccp_feat_finalise_settings(struct dccp_sock *dp);
 extern int  dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq);
 extern int  dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*,
                                   struct sk_buff *skb);
+extern int  dccp_feat_activate_values(struct sock *sk, struct list_head *fn);
 extern void dccp_feat_list_purge(struct list_head *fn_list);
 
 extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index da3bbad9d50d..f78bd357b5b1 100644
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -25,11 +25,101 @@
 
 #define DCCP_FEAT_SP_NOAGREE (-123)
 
+/*
+ * Feature activation handlers.
+ *
+ * These all use an u64 argument, to provide enough room for NN/SP features. At
+ * this stage the negotiated values have been checked to be within their range.
+ */
+static int dccp_hdlr_ccid(struct sock *sk, u64 ccid, bool rx)
+{
+        struct dccp_sock *dp = dccp_sk(sk);
+        struct ccid *new_ccid = ccid_new(ccid, sk, rx, gfp_any());
+
+        if (new_ccid == NULL)
+                return -ENOMEM;
+
+        if (rx) {
+                ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
+                dp->dccps_hc_rx_ccid = new_ccid;
+        } else {
+                ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
+                dp->dccps_hc_tx_ccid = new_ccid;
+        }
+        return 0;
+}
+
+static int dccp_hdlr_seq_win(struct sock *sk, u64 seq_win, bool rx)
+{
+        if (!rx)
+                dccp_msk(sk)->dccpms_sequence_window = seq_win;
+        return 0;
+}
+
+static int dccp_hdlr_ack_ratio(struct sock *sk, u64 ratio, bool rx)
+{
+        if (rx)
+                dccp_sk(sk)->dccps_r_ack_ratio = ratio;
+        else
+                dccp_sk(sk)->dccps_l_ack_ratio = ratio;
+        return 0;
+}
+
+static int dccp_hdlr_ackvec(struct sock *sk, u64 enable, bool rx)
+{
+        struct dccp_sock *dp = dccp_sk(sk);
+
+        if (rx) {
+                if (enable && dp->dccps_hc_rx_ackvec == NULL) {
+                        dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(gfp_any());
+                        if (dp->dccps_hc_rx_ackvec == NULL)
+                                return -ENOMEM;
+                } else if (!enable) {
+                        dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
+                        dp->dccps_hc_rx_ackvec = NULL;
+                }
+        }
+        return 0;
+}
+
+static int dccp_hdlr_ndp(struct sock *sk, u64 enable, bool rx)
+{
+        if (!rx)
+                dccp_msk(sk)->dccpms_send_ndp_count = (enable > 0);
+        return 0;
+}
+
+/*
+ * Minimum Checksum Coverage is located at the RX side (9.2.1). This means that
+ * `rx' holds when the sending peer informs about his partial coverage via a
+ * ChangeR() option. In the other case, we are the sender and the receiver
+ * announces its coverage via ChangeL() options. The policy here is to honour
+ * such communication by enabling the corresponding partial coverage - but only
+ * if it has not been set manually before; the warning here means that all
+ * packets will be dropped.
+ */
+static int dccp_hdlr_min_cscov(struct sock *sk, u64 cscov, bool rx)
+{
+        struct dccp_sock *dp = dccp_sk(sk);
+
+        if (rx)
+                dp->dccps_pcrlen = cscov;
+        else {
+                if (dp->dccps_pcslen == 0)
+                        dp->dccps_pcslen = cscov;
+                else if (cscov > dp->dccps_pcslen)
+                        DCCP_WARN("CsCov %u too small, peer requires >= %u\n",
+                                  dp->dccps_pcslen, (u8)cscov);
+        }
+        return 0;
+}
+
 static const struct {
         u8                      feat_num;               /* DCCPF_xxx */
         enum dccp_feat_type     rxtx;                   /* RX or TX  */
         enum dccp_feat_type     reconciliation;         /* SP or NN  */
         u8                      default_value;          /* as in 6.4 */
+        int (*activation_hdlr)(struct sock *sk, u64 val, bool rx);
 /*
  *    Lookup table for location and type of features (from RFC 4340/4342)
  *  +--------------------------+----+-----+----+----+---------+-----------+
@@ -49,16 +139,16 @@ static const struct {
  *  +--------------------------+----+-----+----+----+---------+-----------+
  */
 } dccp_feat_table[] = {
-        { DCCPF_CCID,            FEAT_AT_TX, FEAT_SP, 2 },
-        { DCCPF_SHORT_SEQNOS,    FEAT_AT_TX, FEAT_SP, 0 },
-        { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100 },
-        { DCCPF_ECN_INCAPABLE,   FEAT_AT_RX, FEAT_SP, 0 },
-        { DCCPF_ACK_RATIO,       FEAT_AT_TX, FEAT_NN, 2 },
-        { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0 },
-        { DCCPF_SEND_NDP_COUNT,  FEAT_AT_TX, FEAT_SP, 0 },
-        { DCCPF_MIN_CSUM_COVER,  FEAT_AT_RX, FEAT_SP, 0 },
-        { DCCPF_DATA_CHECKSUM,   FEAT_AT_RX, FEAT_SP, 0 },
-        { DCCPF_SEND_LEV_RATE,   FEAT_AT_RX, FEAT_SP, 0 },
+        { DCCPF_CCID,            FEAT_AT_TX, FEAT_SP, 2,   dccp_hdlr_ccid     },
+        { DCCPF_SHORT_SEQNOS,    FEAT_AT_TX, FEAT_SP, 0,   NULL },
+        { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100, dccp_hdlr_seq_win  },
+        { DCCPF_ECN_INCAPABLE,   FEAT_AT_RX, FEAT_SP, 0,   NULL },
+        { DCCPF_ACK_RATIO,       FEAT_AT_TX, FEAT_NN, 2,   dccp_hdlr_ack_ratio},
+        { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0,   dccp_hdlr_ackvec   },
+        { DCCPF_SEND_NDP_COUNT,  FEAT_AT_TX, FEAT_SP, 0,   dccp_hdlr_ndp      },
+        { DCCPF_MIN_CSUM_COVER,  FEAT_AT_RX, FEAT_SP, 0,   dccp_hdlr_min_cscov},
+        { DCCPF_DATA_CHECKSUM,   FEAT_AT_RX, FEAT_SP, 0,   NULL },
+        { DCCPF_SEND_LEV_RATE,   FEAT_AT_RX, FEAT_SP, 0,   NULL },
 };
 #define DCCP_FEAT_SUPPORTED_MAX         ARRAY_SIZE(dccp_feat_table)
 
@@ -99,6 +189,41 @@ static int dccp_feat_default_value(u8 feat_num)
         return idx < 0 ? : dccp_feat_table[idx].default_value;
 }
 
+static int __dccp_feat_activate(struct sock *sk, const int idx,
+                                const bool is_local, dccp_feat_val const *fval)
+{
+        bool rx;
+        u64 val;
+
+        if (idx < 0 || idx >= DCCP_FEAT_SUPPORTED_MAX)
+                return -1;
+        if (dccp_feat_table[idx].activation_hdlr == NULL)
+                return 0;
+
+        if (fval == NULL) {
+                val = dccp_feat_table[idx].default_value;
+        } else if (dccp_feat_table[idx].reconciliation == FEAT_SP) {
+                if (fval->sp.vec == NULL) {
+                        /*
+                         * This can happen when an empty Confirm is sent
+                         * for an SP (i.e. known) feature. In this case
+                         * we would be using the default anyway.
+                         */
+                        DCCP_CRIT("Feature #%d undefined: using default", idx);
+                        val = dccp_feat_table[idx].default_value;
+                } else {
+                        val = fval->sp.vec[0];
+                }
+        } else {
+                val = fval->nn;
+        }
+
+        /* Location is RX if this is a local-RX or remote-TX feature */
+        rx = (is_local == (dccp_feat_table[idx].rxtx == FEAT_AT_RX));
+
+        return dccp_feat_table[idx].activation_hdlr(sk, val, rx);
+}
+
 /* Test for "Req'd" feature (RFC 4340, 6.4) */
 static inline int dccp_feat_must_be_understood(u8 feat_num)
 {
@@ -1506,6 +1631,74 @@ out:
 
 EXPORT_SYMBOL_GPL(dccp_feat_init);
 
+int dccp_feat_activate_values(struct sock *sk, struct list_head *fn_list)
+{
+        struct dccp_sock *dp = dccp_sk(sk);
+        struct dccp_feat_entry *cur, *next;
+        int idx;
+        dccp_feat_val *fvals[DCCP_FEAT_SUPPORTED_MAX][2] = {
+                 [0 ... DCCP_FEAT_SUPPORTED_MAX-1] = { NULL, NULL }
+        };
+
+        list_for_each_entry(cur, fn_list, node) {
+                /*
+                 * An empty Confirm means that either an unknown feature type
+                 * or an invalid value was present. In the first case there is
+                 * nothing to activate, in the other the default value is used.
+                 */
+                if (cur->empty_confirm)
+                        continue;
+
+                idx = dccp_feat_index(cur->feat_num);
+                if (idx < 0) {
+                        DCCP_BUG("Unknown feature %u", cur->feat_num);
+                        goto activation_failed;
+                }
+                if (cur->state != FEAT_STABLE) {
+                        DCCP_CRIT("Negotiation of %s %u failed in state %u",
+                                  cur->is_local ? "local" : "remote",
+                                  cur->feat_num, cur->state);
+                        goto activation_failed;
+                }
+                fvals[idx][cur->is_local] = &cur->val;
+        }
+
+        /*
+         * Activate in decreasing order of index, so that the CCIDs are always
+         * activated as the last feature. This avoids the case where a CCID
+         * relies on the initialisation of one or more features that it depends
+         * on (e.g. Send NDP Count, Send Ack Vector, and Ack Ratio features).
+         */
+        for (idx = DCCP_FEAT_SUPPORTED_MAX; --idx >= 0;)
+                if (__dccp_feat_activate(sk, idx, 0, fvals[idx][0]) ||
+                    __dccp_feat_activate(sk, idx, 1, fvals[idx][1])) {
+                        DCCP_CRIT("Could not activate %d", idx);
+                        goto activation_failed;
+                }
+
+        /* Clean up Change options which have been confirmed already */
+        list_for_each_entry_safe(cur, next, fn_list, node)
+                if (!cur->needs_confirm)
+                        dccp_feat_list_pop(cur);
+
+        dccp_pr_debug("Activation OK\n");
+        return 0;
+
+activation_failed:
+        /*
+         * We clean up everything that may have been allocated, since
+         * it is difficult to track at which stage negotiation failed.
+         * This is ok, since all allocation functions below are robust
+         * against NULL arguments.
+         */
+        ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
+        ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
+        dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
+        dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
+        dp->dccps_hc_rx_ackvec = NULL;
+        return -1;
+}
+
 #ifdef CONFIG_IP_DCCP_DEBUG
 const char *dccp_feat_typename(const u8 type)
 {