[DCCP] ackvec: infrastructure for sending more than one ackvec per packet

Commiter note:

This was split from Andrea's original patch, in the process I changed the type
of the ackvec index fields to u16 instead of to int and haven't folded
dccp_ackvec_parse with dccp_ackvec_check_rcv_ackno.

Next patch will actually do the insertion of more than one ackvec per packet,
using, initially, up to a max of 2 ackvecs as per Andrea's original patch, then
I'll work on support for larger ackvecs, be it using a sysctl or using
setsockopt.

Signed-off-by: Andrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

1 files changed, 11 insertions, 7 deletions

diff --git a/net/dccp/ackvec.h b/net/dccp/ackvec.h
index d6a58db5fb13..96504a3b16e4 100644
--- a/net/dccp/ackvec.h
+++ b/net/dccp/ackvec.h
@@ -17,7 +17,9 @@
 #include <linux/types.h>
 
 /* Read about the ECN nonce to see why it is 253 */
-#define DCCP_MAX_ACKVEC_LEN 253
+#define DCCP_MAX_ACKVEC_OPT_LEN 253
+/* We can spread an ack vector across multiple options */
+#define DCCP_MAX_ACKVEC_LEN (DCCP_MAX_ACKVEC_OPT_LEN * 2)
 
 #define DCCP_ACKVEC_STATE_RECEIVED      0
 #define DCCP_ACKVEC_STATE_ECN_MARKED    (1 << 6)
@@ -51,8 +53,8 @@ struct dccp_ackvec {
         u64             dccpav_buf_ackno;
         struct list_head dccpav_records;
         struct timeval  dccpav_time;
-        u8              dccpav_buf_head;
-        u8              dccpav_vec_len;
+        u16             dccpav_buf_head;
+        u16             dccpav_vec_len;
         u8              dccpav_buf_nonce;
         u8              dccpav_ack_nonce;
         u8              dccpav_buf[DCCP_MAX_ACKVEC_LEN];
@@ -75,9 +77,9 @@ struct dccp_ackvec_record {
         struct list_head dccpavr_node;
         u64              dccpavr_ack_seqno;
         u64              dccpavr_ack_ackno;
-        u8               dccpavr_ack_ptr;
+        u16              dccpavr_ack_ptr;
+        u16              dccpavr_sent_len;
         u8               dccpavr_ack_nonce;
-        u8               dccpavr_sent_len;
 };
 
 struct sock;
@@ -96,7 +98,8 @@ extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
 extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
                                         struct sock *sk, const u64 ackno);
 extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
-                             const u8 opt, const u8 *value, const u8 len);
+                             u64 *ackno, const u8 opt,
+                             const u8 *value, const u8 len);
 
 extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
 
@@ -135,7 +138,8 @@ static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
 }
 
 static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
-                                    const u8 opt, const u8 *value, const u8 len)
+                                    const u64 *ackno, const u8 opt,
+                                    const u8 *value, const u8 len)
 {
         return -1;
 }