return 0;
}
+/**
+ * dccp_feat_push_confirm - Add a Confirm entry to the FN list
+ * @fn_list: feature-negotiation list to add to
+ * @feat: one of %dccp_feature_numbers
+ * @local: whether local (1) or remote (0) @feat_num is being confirmed
+ * @fval: pointer to NN/SP value to be inserted or NULL
+ * Returns 0 on success, a Reset code for further processing otherwise.
+ */
+static int dccp_feat_push_confirm(struct list_head *fn_list, u8 feat, u8 local,
+ dccp_feat_val *fval)
+{
+ struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local);
+
+ if (new == NULL)
+ return DCCP_RESET_CODE_TOO_BUSY;
+
+ new->feat_num = feat;
+ new->is_local = local;
+ new->state = FEAT_STABLE; /* transition in 6.6.2 */
+ new->needs_confirm = 1;
+ new->empty_confirm = (fval == NULL);
+ new->val.nn = 0; /* zeroes the whole structure */
+ if (!new->empty_confirm)
+ new->val = *fval;
+ new->needs_mandatory = 0;
+
+ return 0;
+}
+
+static int dccp_push_empty_confirm(struct list_head *fn_list, u8 feat, u8 local)
+{
+ return dccp_feat_push_confirm(fn_list, feat, local, NULL);
+}
+
static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry)
{
list_del(&entry->node);
return 0;
}
-#endif /* (later) */
static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
u8 type, u8 feature)
}
EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
+#endif /* (later) */
int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
u8 *val, u8 len)
EXPORT_SYMBOL_GPL(dccp_feat_clone);
+/**
+ * dccp_feat_change_recv - Process incoming ChangeL/R options
+ * @fn: feature-negotiation list to update
+ * @is_mandatory: whether the Change was preceded by a Mandatory option
+ * @opt: %DCCPO_CHANGE_L or %DCCPO_CHANGE_R
+ * @feat: one of %dccp_feature_numbers
+ * @val: NN value or SP value/preference list
+ * @len: length of @val in bytes
+ * @server: whether this node is the server (1) or the client (0)
+ */
+static u8 dccp_feat_change_recv(struct list_head *fn, u8 is_mandatory, u8 opt,
+ u8 feat, u8 *val, u8 len, const bool server)
+{
+ u8 defval, type = dccp_feat_type(feat);
+ const bool local = (opt == DCCPO_CHANGE_R);
+ struct dccp_feat_entry *entry;
+ dccp_feat_val fval;
+
+ if (len == 0 || type == FEAT_UNKNOWN) /* 6.1 and 6.6.8 */
+ goto unknown_feature_or_value;
+
+ /*
+ * Negotiation of NN features: Change R is invalid, so there is no
+ * simultaneous negotiation; hence we do not look up in the list.
+ */
+ if (type == FEAT_NN) {
+ if (local || len > sizeof(fval.nn))
+ goto unknown_feature_or_value;
+
+ /* 6.3.2: "The feature remote MUST accept any valid value..." */
+ fval.nn = dccp_decode_value_var(val, len);
+ if (!dccp_feat_is_valid_nn_val(feat, fval.nn))
+ goto unknown_feature_or_value;
+
+ return dccp_feat_push_confirm(fn, feat, local, &fval);
+ }
+
+ /*
+ * Unidirectional/simultaneous negotiation of SP features (6.3.1)
+ */
+ entry = dccp_feat_list_lookup(fn, feat, local);
+ if (entry == NULL) {
+ /*
+ * No particular preferences have been registered. We deal with
+ * this situation by assuming that all valid values are equally
+ * acceptable, and apply the following checks:
+ * - if the peer's list is a singleton, we accept a valid value;
+ * - if we are the server, we first try to see if the peer (the
+ * client) advertises the default value. If yes, we use it,
+ * otherwise we accept the preferred value;
+ * - else if we are the client, we use the first list element.
+ */
+ if (dccp_feat_clone_sp_val(&fval, val, 1))
+ return DCCP_RESET_CODE_TOO_BUSY;
+
+ if (len > 1 && server) {
+ defval = dccp_feat_default_value(feat);
+ if (dccp_feat_preflist_match(&defval, 1, val, len) > -1)
+ fval.sp.vec[0] = defval;
+ } else if (!dccp_feat_is_valid_sp_val(feat, fval.sp.vec[0])) {
+ kfree(fval.sp.vec);
+ goto unknown_feature_or_value;
+ }
+
+ /* Treat unsupported CCIDs like invalid values */
+ if (feat == DCCPF_CCID && !ccid_support_check(fval.sp.vec, 1)) {
+ kfree(fval.sp.vec);
+ goto not_valid_or_not_known;
+ }
+
+ return dccp_feat_push_confirm(fn, feat, local, &fval);
+
+ } else if (entry->state == FEAT_UNSTABLE) { /* 6.6.2 */
+ return 0;
+ }
+
+ if (dccp_feat_reconcile(&entry->val, val, len, server, true)) {
+ entry->empty_confirm = 0;
+ } else if (is_mandatory) {
+ return DCCP_RESET_CODE_MANDATORY_ERROR;
+ } else if (entry->state == FEAT_INITIALISING) {
+ /*
+ * Failed simultaneous negotiation (server only): try to `save'
+ * the connection by checking whether entry contains the default
+ * value for @feat. If yes, send an empty Confirm to signal that
+ * the received Change was not understood - which implies using
+ * the default value.
+ * If this also fails, we use Reset as the last resort.
+ */
+ WARN_ON(!server);
+ defval = dccp_feat_default_value(feat);
+ if (!dccp_feat_reconcile(&entry->val, &defval, 1, server, true))
+ return DCCP_RESET_CODE_OPTION_ERROR;
+ entry->empty_confirm = 1;
+ }
+ entry->needs_confirm = 1;
+ entry->needs_mandatory = 0;
+ entry->state = FEAT_STABLE;
+ return 0;
+
+unknown_feature_or_value:
+ if (!is_mandatory)
+ return dccp_push_empty_confirm(fn, feat, local);
+
+not_valid_or_not_known:
+ return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR
+ : DCCP_RESET_CODE_OPTION_ERROR;
+}
+
+/**
+ * dccp_feat_parse_options - Process Feature-Negotiation Options
+ * @sk: for general use and used by the client during connection setup
+ * @dreq: used by the server during connection setup
+ * @mandatory: whether @opt was preceded by a Mandatory option
+ * @opt: %DCCPO_CHANGE_L | %DCCPO_CHANGE_R | %DCCPO_CONFIRM_L | %DCCPO_CONFIRM_R
+ * @feat: one of %dccp_feature_numbers
+ * @val: value contents of @opt
+ * @len: length of @val in bytes
+ * Returns 0 on success, a Reset code for ending the connection otherwise.
+ */
+int dccp_feat_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
+ u8 mandatory, u8 opt, u8 feat, u8 *val, u8 len)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg;
+ bool server = false;
+
+ switch (sk->sk_state) {
+ /*
+ * Negotiation during connection setup
+ */
+ case DCCP_LISTEN:
+ server = true; /* fall through */
+ case DCCP_REQUESTING:
+ switch (opt) {
+ case DCCPO_CHANGE_L:
+ case DCCPO_CHANGE_R:
+ return dccp_feat_change_recv(fn, mandatory, opt, feat,
+ val, len, server);
+ }
+ }
+ return 0; /* ignore FN options in all other states */
+}
+
int dccp_feat_init(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);
projects / deliverable / linux.git / blobdiff