[DCCP]: Processing Confirm options
Analogous to the previous patch, this adds code to interpret incoming Confirm feature-negotiation
options. Both functions operate on the feature-negotiation list of either the request_sock (server)
or the dccp_sock (client).
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
---
net/dccp/feat.c | 151 ++++++++++++++++++++++++++++++++++-------------------
net/dccp/feat.h | 2
net/dccp/options.c | 16 -----
3 files changed, 99 insertions(+), 70 deletions(-)
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -95,6 +95,13 @@ static int dccp_feat_default_value(u8 fe
return idx < 0? idx : dccp_feat_table[idx].default_value;
}
+/* Test for "Req'd" feature (RFC 4340, 6.4) */
+static inline int dccp_feat_must_be_understood(u8 feat_num)
+{
+ return feat_num == DCCPF_CCID || feat_num == DCCPF_SHORT_SEQNOS ||
+ feat_num == DCCPF_SEQUENCE_WINDOW;
+}
+
/* copy constructor, fval must not already contain allocated memory */
static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len)
{
@@ -829,6 +836,92 @@ not_valid_or_not_known:
}
/**
+ * dccp_feat_confirm_recv - Process received Confirm options
+ * @fn: feature-negotiation list to update
+ * @is_mandatory: whether the Confirm was preceded by a Mandatory option
+ * @opt: %DCCPO_CONFIRM_L or %DCCPO_CONFIRM_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 server (1) or client (0)
+ */
+static u8 dccp_feat_confirm_recv(struct list_head *fn, u8 is_mandatory, u8 opt,
+ u8 feat, u8 *val, u8 len, const bool server)
+{
+ u8 *plist, plen, type = dccp_feat_type(feat);
+ const bool local = (opt == DCCPO_CONFIRM_R);
+ struct dccp_feat_entry *entry = dccp_feat_list_lookup(fn, feat, local);
+
+ if (entry == NULL) { /* nothing queued: ignore or handle error */
+ if (is_mandatory && type == FEAT_UNKNOWN)
+ return DCCP_RESET_CODE_MANDATORY_ERROR;
+
+ if (!local && type == FEAT_NN) /* 6.3.2 */
+ goto confirmation_failed;
+ return 0;
+ }
+
+ if (entry->state != FEAT_CHANGING) /* 6.6.2 */
+ return 0;
+
+ if (len == 0) { /* Empty Confirm */
+ if (dccp_feat_must_be_understood(feat)) /* 6.6.7 */
+ goto confirmation_failed;
+ /*
+ * Empty Confirm during connection setup: this means reverting
+ * to the `old' value, which in this case is the default. Since
+ * we handle default values automatically when no other values
+ * have been set, we revert to the old value by removing this
+ * entry from the list.
+ */
+ list_del(&entry->node);
+ dccp_feat_entry_destructor(entry);
+ return 0;
+ }
+
+ if (type == FEAT_NN) {
+ if (len > sizeof(entry->val.nn))
+ goto confirmation_failed;
+
+ if (entry->val.nn == dccp_decode_value_var(val, len))
+ goto confirmation_succeeded;
+
+ DCCP_WARN("Bogus Confirm for non-existing value\n");
+ goto confirmation_failed;
+ }
+
+ /*
+ * Parsing SP Confirms: the first element of @val is the preferred
+ * SP value which the peer confirms, the remainder depends on @len.
+ */
+ if (!dccp_feat_sp_list_ok(feat, val, len))
+ goto confirmation_failed;
+
+ if (len == 1) { /* peer didn't supply a preference list */
+ plist = val;
+ plen = len;
+ } else { /* preferred value + preference list */
+ plist = val + 1;
+ plen = len - 1;
+ }
+
+ /* Check whether the peer got the reconciliation right (6.6.8) */
+ if (dccp_feat_reconcile(&entry->val, plist, plen, server, 0) != *val) {
+ DCCP_WARN("Confirm selected the wrong value %u\n", *val);
+ return DCCP_RESET_CODE_OPTION_ERROR;
+ }
+ entry->val.sp.vec[0] = *val;
+
+confirmation_succeeded:
+ entry->state = FEAT_STABLE;
+ return 0;
+
+confirmation_failed:
+ 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
@@ -858,65 +951,15 @@ int dccp_feat_parse_options(struct sock
case DCCPO_CHANGE_R:
return dccp_feat_change_recv(fn, mandatory, opt, feat,
val, len, server);
+ case DCCPO_CONFIRM_R:
+ case DCCPO_CONFIRM_L:
+ return dccp_feat_confirm_recv(fn, mandatory, opt, feat,
+ val, len, server);
}
}
return 0; /* ignore FN options in all other states */
}
-int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
- u8 *val, u8 len)
-{
- u8 t;
- struct dccp_opt_pend *opt;
- struct dccp_minisock *dmsk = dccp_msk(sk);
- int found = 0;
- int all_confirmed = 1;
-
- /* Ignore Confirm options other than during connection setup */
- if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
- return 0;
- dccp_feat_debug(type, feature, *val);
-
- /* locate our change request */
- switch (type) {
- case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
- case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
- default: DCCP_WARN("invalid type %d\n", type);
- return 1;
-
- }
- /* XXX sanity check feature value */
-
- list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
- if (!opt->dccpop_conf && opt->dccpop_type == t &&
- opt->dccpop_feat == feature) {
- found = 1;
- dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
-
- /* XXX do sanity check */
-
- opt->dccpop_conf = 1;
-
- /* We got a confirmation---change the option */
- dccp_feat_update(sk, opt->dccpop_type,
- opt->dccpop_feat, *val);
-
- /* XXX check the return value of dccp_feat_update */
- break;
- }
-
- if (!opt->dccpop_conf)
- all_confirmed = 0;
- }
-
- if (!found)
- dccp_pr_debug("%s(%d, ...) never requested\n",
- dccp_feat_typename(type), feature);
- return 0;
-}
-
-EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
-
void dccp_feat_clean(struct dccp_minisock *dmsk)
{
struct dccp_opt_pend *opt, *next;
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -125,26 +125,14 @@ int dccp_parse_options(struct sock *sk,
dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
(unsigned long long)opt_recv->dccpor_ndp);
break;
- case DCCPO_CHANGE_L:
- case DCCPO_CHANGE_R:
- if (pkt_type == DCCP_PKT_DATA)
+ case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
+ if (pkt_type == DCCP_PKT_DATA) /* RFC 4340, 6 */
break;
rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
*value, value + 1, len - 1);
if (rc)
goto out_invalid_option;
break;
- case DCCPO_CONFIRM_L:
- /* fall through */
- case DCCPO_CONFIRM_R:
- if (pkt_type == DCCP_PKT_DATA)
- break;
- if (len < 2) /* FIXME this disallows empty confirm */
- goto out_invalid_option;
- if (dccp_feat_confirm_recv(sk, opt, *value,
- value + 1, len - 1))
- goto out_invalid_option;
- break;
case DCCPO_ACK_VECTOR_0:
case DCCPO_ACK_VECTOR_1:
if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
--- a/net/dccp/feat.h
+++ b/net/dccp/feat.h
@@ -105,8 +105,6 @@ extern int dccp_feat_register_change(st
u8 is_local, u8 *val, u8 len);
extern int dccp_feat_parse_options(struct sock *, struct dccp_request_sock *,
u8 mand, u8 opt, u8 feat, u8 *val, u8 len);
-extern int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
- u8 *val, u8 len);
extern void dccp_feat_clean(struct dccp_minisock *dmsk);
extern int dccp_feat_clone(struct sock *oldsk, struct sock *newsk);
extern int dccp_feat_clone_list(struct list_head const *, struct list_head *);
-
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