dccp: Per-socket initialisation of feature negotiation

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.

Thanks to Wei Yongjun for help with the IPv6 side of this patch.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>

9 files changed, 37 insertions, 6 deletions

diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index 3978aff197d9..484b8a1fb023 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -412,6 +412,7 @@ extern void dccp_minisock_init(struct dccp_minisock *dmsk);
  * @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
  * The following two fields are analogous to the ones in dccp_sock:
  * @dreq_timestamp_echo: last received timestamp to echo (13.1)
  * @dreq_timestamp_echo: the time of receiving the last @dreq_timestamp_echo
@@ -421,6 +422,7 @@ struct dccp_request_sock {
         __u64                    dreq_iss;
         __u64                    dreq_isr;
         __be32                   dreq_service;
+        struct list_head         dreq_featneg;
         __u32                    dreq_timestamp_echo;
         __u32                    dreq_timestamp_time;
 };
@@ -498,6 +500,7 @@ 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)
@@ -535,6 +538,7 @@ struct dccp_sock {
         __u64                           dccps_ndp_count:48;
         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;
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index b4bc6e095a0e..ab096c06bba0 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -252,7 +252,8 @@ extern const char *dccp_state_name(const int state);
 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);
 
diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index 2ec2cd117699..faade82856fe 100644
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -279,6 +279,25 @@ void dccp_feat_list_purge(struct list_head *fn_list)
 }
 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)
 {
diff --git a/net/dccp/feat.h b/net/dccp/feat.h
index 94203c230c65..7e953fd0a79b 100644
--- a/net/dccp/feat.h
+++ b/net/dccp/feat.h
@@ -95,6 +95,7 @@ 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 *);
 extern int  dccp_feat_init(struct dccp_minisock *dmsk);
 
 #endif /* _DCCP_FEAT_H */
diff --git a/net/dccp/input.c b/net/dccp/input.c
index 779d0ed9ae94..3070015edc75 100644
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -590,8 +590,6 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                         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)
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 882c5c4de69e..0ce84ea89119 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -595,7 +595,8 @@ int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
         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))
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 5e1ee0da2c40..33e8a1ea3041 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -424,7 +424,8 @@ static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
         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))
diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c
index b2804e2d1b8c..e487133ae079 100644
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
@@ -125,6 +125,7 @@ struct sock *dccp_create_openreq_child(struct sock *sk,
                 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
                 newicsk->icsk_rto           = DCCP_TIMEOUT_INIT;
 
+                INIT_LIST_HEAD(&newdp->dccps_featneg);
                 if (dccp_feat_clone(sk, newsk))
                         goto out_free;
 
@@ -304,7 +305,8 @@ void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
 
 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);
 
@@ -312,6 +314,9 @@ void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb)
         inet_rsk(req)->acked      = 0;
         req->rcv_wnd              = sysctl_dccp_feat_sequence_window;
         dreq->dreq_timestamp_echo = 0;
+
+        /* inherit feature negotiation options from listening socket */
+        return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
 }
 
 EXPORT_SYMBOL_GPL(dccp_reqsk_init);
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index d0bd34819761..1cdf4ae99605 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -193,6 +193,7 @@ int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
 
         dccp_init_xmit_timers(sk);
 
+        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