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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2008-12-01 23:27:31 -0800
committerDavid S. Miller <davem@davemloft.net>2008-12-01 23:27:31 -0800
commit0971d17ca3d80f61863f4750091a64448bf91600 (patch)
tree4f4a4f334b382c873462788adf915e85230f5363 /net/dccp/feat.c
parent25f13048bce61f33f6a102e0bf377fd3922ed364 (diff)
dccp: Insert feature-negotiation options into skb
This patch replaces the earlier insertion routine from options.c, so that code specific to feature negotiation can remain in feat.c. This is possible by calling a function already existing in options.c. 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>
Diffstat (limited to 'net/dccp/feat.c')
-rw-r--r--net/dccp/feat.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index 2c2216f64b1b..d90caa7198c3 100644
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -272,6 +272,20 @@ cloning_failed:
return -ENOMEM;
}
+/**
+ * dccp_feat_valid_nn_length - Enforce length constraints on NN options
+ * Length is between 0 and %DCCP_OPTVAL_MAXLEN. Used for outgoing packets only,
+ * incoming options are accepted as long as their values are valid.
+ */
+static u8 dccp_feat_valid_nn_length(u8 feat_num)
+{
+ if (feat_num == DCCPF_ACK_RATIO) /* RFC 4340, 11.3 and 6.6.8 */
+ return 2;
+ if (feat_num == DCCPF_SEQUENCE_WINDOW) /* RFC 4340, 7.5.2 and 6.5 */
+ return 6;
+ return 0;
+}
+
static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val)
{
switch (feat_num) {
@@ -314,6 +328,57 @@ static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len)
}
/**
+ * dccp_feat_insert_opts - Generate FN options from current list state
+ * @skb: next sk_buff to be sent to the peer
+ * @dp: for client during handshake and general negotiation
+ * @dreq: used by the server only (all Changes/Confirms in LISTEN/RESPOND)
+ */
+int dccp_feat_insert_opts(struct dccp_sock *dp, struct dccp_request_sock *dreq,
+ struct sk_buff *skb)
+{
+ struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg;
+ struct dccp_feat_entry *pos, *next;
+ u8 opt, type, len, *ptr, nn_in_nbo[DCCP_OPTVAL_MAXLEN];
+ bool rpt;
+
+ /* put entries into @skb in the order they appear in the list */
+ list_for_each_entry_safe_reverse(pos, next, fn, node) {
+ opt = dccp_feat_genopt(pos);
+ type = dccp_feat_type(pos->feat_num);
+ rpt = false;
+
+ if (pos->empty_confirm) {
+ len = 0;
+ ptr = NULL;
+ } else {
+ if (type == FEAT_SP) {
+ len = pos->val.sp.len;
+ ptr = pos->val.sp.vec;
+ rpt = pos->needs_confirm;
+ } else if (type == FEAT_NN) {
+ len = dccp_feat_valid_nn_length(pos->feat_num);
+ ptr = nn_in_nbo;
+ dccp_encode_value_var(pos->val.nn, ptr, len);
+ } else {
+ DCCP_BUG("unknown feature %u", pos->feat_num);
+ return -1;
+ }
+ }
+
+ if (dccp_insert_fn_opt(skb, opt, pos->feat_num, ptr, len, rpt))
+ return -1;
+ if (pos->needs_mandatory && dccp_insert_option_mandatory(skb))
+ return -1;
+ /*
+ * Enter CHANGING after transmitting the Change option (6.6.2).
+ */
+ if (pos->state == FEAT_INITIALISING)
+ pos->state = FEAT_CHANGING;
+ }
+ return 0;
+}
+
+/**
* __feat_register_nn - Register new NN value on socket
* @fn: feature-negotiation list to register with
* @feat: an NN feature from %dccp_feature_numbers

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