diff options
| -rw-r--r-- | net/dccp/dccp.h | 1 | ||||
| -rw-r--r-- | net/dccp/feat.c | 57 |
2 files changed, 58 insertions, 0 deletions
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h index 94ae6d41d72..0a07b2e24e6 100644 --- a/net/dccp/dccp.h +++ b/net/dccp/dccp.h @@ -436,6 +436,7 @@ static inline int dccp_ack_pending(const struct sock *sk) inet_csk_ack_scheduled(sk); } +extern int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val); 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*, diff --git a/net/dccp/feat.c b/net/dccp/feat.c index 3abacad0b22..5be8b85ac74 100644 --- a/net/dccp/feat.c +++ b/net/dccp/feat.c @@ -13,6 +13,7 @@ * ----------- * o Feature negotiation is coordinated with connection setup (as in TCP), wild * changes of parameters of an established connection are not supported. + * o Changing NN values (Ack Ratio only) is supported in state OPEN/PARTOPEN. * o All currently known SP features have 1-byte quantities. If in the future * extensions of RFCs 4340..42 define features with item lengths larger than * one byte, a feature-specific extension of the code will be required. @@ -337,6 +338,20 @@ static int __dccp_feat_activate(struct sock *sk, const int idx, return dccp_feat_table[idx].activation_hdlr(sk, val, rx); } +/** + * dccp_feat_activate - Activate feature value on socket + * @sk: fully connected DCCP socket (after handshake is complete) + * @feat_num: feature to activate, one of %dccp_feature_numbers + * @local: whether local (1) or remote (0) @feat_num is meant + * @fval: the value (SP or NN) to activate, or NULL to use the default value + * For general use this function is preferable over __dccp_feat_activate(). + */ +static int dccp_feat_activate(struct sock *sk, u8 feat_num, bool local, + dccp_feat_val const *fval) +{ + return __dccp_feat_activate(sk, dccp_feat_index(feat_num), local, fval); +} + /* Test for "Req'd" feature (RFC 4340, 6.4) */ static inline int dccp_feat_must_be_understood(u8 feat_num) { @@ -734,6 +749,48 @@ int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val) return __feat_register_nn(&dccp_sk(sk)->dccps_featneg, feat, 0, val); } +/** + * dccp_feat_signal_nn_change - Update NN values for an established connection + * @sk: DCCP socket of an established connection + * @feat: NN feature number from %dccp_feature_numbers + * @nn_val: the new value to use + * This function is used to communicate NN updates out-of-band. The difference + * to feature negotiation during connection setup is that values are activated + * immediately after validation, i.e. we don't wait for the Confirm: either the + * value is accepted by the peer (and then the waiting is futile), or it is not + * (Reset or empty Confirm). We don't accept empty Confirms - transmitted values + * are validated, and the peer "MUST accept any valid value" (RFC 4340, 6.3.2). + */ +int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val) +{ + struct list_head *fn = &dccp_sk(sk)->dccps_featneg; + dccp_feat_val fval = { .nn = nn_val }; + struct dccp_feat_entry *entry; + + if (sk->sk_state != DCCP_OPEN && sk->sk_state != DCCP_PARTOPEN) + return 0; + + if (dccp_feat_type(feat) != FEAT_NN || + !dccp_feat_is_valid_nn_val(feat, nn_val)) + return -EINVAL; + + entry = dccp_feat_list_lookup(fn, feat, 1); + if (entry != NULL) { + dccp_pr_debug("Ignoring %llu, entry %llu exists in state %s\n", + (unsigned long long)nn_val, + (unsigned long long)entry->val.nn, + dccp_feat_sname[entry->state]); + return 0; + } + + if (dccp_feat_activate(sk, feat, 1, &fval)) + return -EADV; + + inet_csk_schedule_ack(sk); + return dccp_feat_push_change(fn, feat, 1, 0, &fval); +} +EXPORT_SYMBOL_GPL(dccp_feat_signal_nn_change); + /* * Tracking features whose value depend on the choice of CCID * |