[DCCP]: Support inserting options during the 3-way handshake

This provides a separate routine to insert options during the initial handshake.
The main purpose is to conduct feature negotiation, for the moment the only user
is the timestamp echo needed for the (CCID3) handshake RTT sample.

Padding of options has been put into a small separate routine, to be shared among
the two functions. This could also be used as a generic routine to finish inserting
options.

Also removed an `XXX' comment since its content was obvious.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 3af3320194f005b1cf513b80d89da27076c215b2..b138e2019d78e7dc8c8afd277cc606a7c7b16c67 100644 (file)
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -428,6 +428,7 @@ static inline int dccp_ack_pending(const struct sock *sk)
 }
 
 extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
+extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
 extern int dccp_insert_option_elapsed_time(struct sock *sk,
                                            struct sk_buff *skb,
                                            u32 elapsed_time);

diff --git a/net/dccp/options.c b/net/dccp/options.c
index 0c996d8c79a31a0ae82de53ffc61d887e231061f..bedb5daaa3c5da7188e2362a42f8950d55643a16 100644 (file)
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -537,6 +537,18 @@ static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
        return 0;
 }
 
+/* The length of all options needs to be a multiple of 4 (5.8) */
+static void dccp_insert_option_padding(struct sk_buff *skb)
+{
+       int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
+
+       if (padding != 0) {
+               padding = 4 - padding;
+               memset(skb_push(skb, padding), 0, padding);
+               DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
+       }
+}
+
 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
 {
        struct dccp_sock *dp = dccp_sk(sk);
@@ -580,18 +592,18 @@ int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
            dccp_insert_option_timestamp_echo(dp, NULL, skb))
                return -1;
 
-       /* XXX: insert other options when appropriate */
+       dccp_insert_option_padding(skb);
+       return 0;
+}
 
-       if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
-               /* The length of all options has to be a multiple of 4 */
-               int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
+int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
+{
+       DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
 
-               if (padding != 0) {
-                       padding = 4 - padding;
-                       memset(skb_push(skb, padding), 0, padding);
-                       DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
-               }
-       }
+       if (dreq->dreq_timestamp_echo != 0 &&
+           dccp_insert_option_timestamp_echo(NULL, dreq, skb))
+               return -1;
 
+       dccp_insert_option_padding(skb);
        return 0;
 }

diff --git a/net/dccp/output.c b/net/dccp/output.c
index b2e17910930dab5b5b0d8e327322551e75635f32..5589a5e581f4add4da4049c478c9e642c4415834 100644 (file)
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -303,7 +303,7 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
        DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
        DCCP_SKB_CB(skb)->dccpd_seq  = dreq->dreq_iss;
 
-       if (dccp_insert_options(sk, skb)) {
+       if (dccp_insert_options_rsk(dreq, skb)) {
                kfree_skb(skb);
                return NULL;
        }