[DCCP]: Socket support for feature negotiation and its initialisation

This provides feature-negotiation initialisation for both DCCP sockets and
DCCP request_sockets, to support feature negotiation during connection setup.

It also resolves a FIXME regarding the congestion control initialisation.

Signed-off-by: Gerrit Renker <[EMAIL PROTECTED]>
---
 include/linux/dccp.h |    4 ++++
 net/dccp/dccp.h      |    3 ++-
 net/dccp/feat.c      |   19 +++++++++++++++++++
 net/dccp/feat.h      |    1 +
 net/dccp/input.c     |    2 --
 net/dccp/ipv4.c      |    3 ++-
 net/dccp/ipv6.c      |    3 ++-
 net/dccp/minisocks.c |    7 ++++++-
 net/dccp/proto.c     |    1 +
 9 files changed, 37 insertions(+), 6 deletions(-)

--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -424,6 +424,7 @@ struct dccp_ts_echo {
  * @dreq_iss: initial sequence number sent on the Response (RFC 4340, 7.1)
  * @dreq_isr: initial sequence number received on the Request
  * @dreq_service: service code present on the Request (there is just one)
+ * @dreq_featneg: feature negotiation options for this connection
  * @dreq_tstamp: most recent timestamp received during connection setup
  */
 struct dccp_request_sock {
@@ -431,6 +432,7 @@ struct dccp_request_sock {
        __u64                    dreq_iss;
        __u64                    dreq_isr;
        __be32                   dreq_service;
+       struct list_head         dreq_featneg;
        struct dccp_ts_echo      *dreq_tstamp;
 };
 
@@ -506,6 +508,7 @@ struct dccp_ackvec;
  * @dccps_mss_cache - current value of MSS (path MTU minus header sizes)
  * @dccps_rate_last - timestamp for rate-limiting DCCP-Sync (RFC 4340, 7.5.4)
  * @dccps_minisock - associated minisock (accessed via dccp_msk)
+ * @dccps_featneg - tracks feature-negotiation state (mostly during handshake)
  * @dccps_hc_rx_ackvec - rx half connection ack vector
  * @dccps_hc_rx_ccid - CCID used for the receiver (or receiving 
half-connection)
  * @dccps_hc_tx_ccid - CCID used for the sender (or sending half-connection)
@@ -542,6 +545,7 @@ struct dccp_sock {
        __u32                           dccps_mss_cache;
        unsigned long                   dccps_rate_last;
        struct dccp_minisock            dccps_minisock;
+       struct list_head                dccps_featneg;
        struct dccp_ackvec              *dccps_hc_rx_ackvec;
        struct ccid                     *dccps_hc_rx_ccid;
        struct ccid                     *dccps_hc_tx_ccid;
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -177,6 +177,7 @@ int dccp_init_sock(struct sock *sk, cons
 
        dccp_minisock_init(&dp->dccps_minisock);
 
+       INIT_LIST_HEAD(&dp->dccps_featneg);
        /*
         * FIXME: We're hardcoding the CCID, and doing this at this point makes
         * the listening (master) sock get CCID control blocks, which is not
--- a/net/dccp/feat.h
+++ b/net/dccp/feat.h
@@ -95,6 +95,7 @@ extern int  dccp_feat_confirm_recv(struc
                                   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 *);
 extern int  dccp_feat_init(struct dccp_minisock *dmsk);
 
 #endif /* _DCCP_FEAT_H */
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -273,6 +273,25 @@ void dccp_feat_list_purge(struct list_he
 
 EXPORT_SYMBOL_GPL(dccp_feat_list_purge);
 
+/* generate @to as full clone of @from - @to must not contain any nodes */
+int dccp_feat_clone_list(struct list_head const *from, struct list_head *to)
+{
+       struct dccp_feat_entry *entry, *new;
+
+       INIT_LIST_HEAD(to);
+       list_for_each_entry(entry, from, node) {
+               new = dccp_feat_clone_entry(entry);
+               if (new == NULL)
+                       goto cloning_failed;
+               list_add_tail(&new->node, to);
+       }
+       return 0;
+
+cloning_failed:
+       dccp_feat_list_purge(to);
+       return -ENOMEM;
+}
+
 int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
                     u8 *val, u8 len, gfp_t gfp)
 {
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -236,7 +236,8 @@ extern const char *dccp_state_name(const
 extern void dccp_set_state(struct sock *sk, const int state);
 extern void dccp_done(struct sock *sk);
 
-extern void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb);
+extern int  dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const 
*dp,
+                           struct sk_buff const *skb);
 
 extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
 
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
@@ -124,6 +124,7 @@ struct sock *dccp_create_openreq_child(s
                newdp->dccps_service       = dreq->dreq_service;
                newicsk->icsk_rto          = DCCP_TIMEOUT_INIT;
 
+               INIT_LIST_HEAD(&newdp->dccps_featneg);
                if (dccp_feat_clone(sk, newsk))
                        goto out_free;
 
@@ -302,7 +303,8 @@ void dccp_reqsk_send_ack(struct sk_buff 
 
 EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
 
-void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb)
+int dccp_reqsk_init(struct request_sock *req,
+                   struct dccp_sock const *dp, struct sk_buff const *skb)
 {
        struct dccp_request_sock *dreq = dccp_rsk(req);
 
@@ -310,6 +312,9 @@ void dccp_reqsk_init(struct request_sock
        inet_rsk(req)->acked    = 0;
        req->rcv_wnd            = sysctl_dccp_feat_sequence_window;
        dreq->dreq_tstamp       = NULL;
+
+       /* inherit feature negotiation options from listening socket */
+       return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
 }
 
 EXPORT_SYMBOL_GPL(dccp_reqsk_init);
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -606,7 +606,8 @@ int dccp_v4_conn_request(struct sock *sk
        if (req == NULL)
                goto drop;
 
-       dccp_reqsk_init(req, skb);
+       if (dccp_reqsk_init(req, dccp_sk(sk), skb))
+               goto drop_and_free;
 
        dreq = dccp_rsk(req);
        if (dccp_parse_options(sk, dreq, skb))
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -419,7 +419,8 @@ static int dccp_v6_conn_request(struct s
        if (req == NULL)
                goto drop;
 
-       dccp_reqsk_init(req, skb);
+       if (dccp_reqsk_init(req, dccp_sk(sk), skb))
+               goto drop_and_free;
 
        dreq = dccp_rsk(req);
        if (dccp_parse_options(sk, dreq, skb))
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -511,8 +511,6 @@ int dccp_rcv_state_process(struct sock *
                        if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
                                                                    skb) < 0)
                                return 1;
-
-                       /* FIXME: do congestion control initialization */
                        goto discard;
                }
                if (dh->dccph_type == DCCP_PKT_RESET)
-
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