---

yaml
---
r: 41615
b: refs/heads/master
c: 60361be
h: refs/heads/master
i:
  41613: b51265e
  41611: d3c6e5b
  41607: eec403f
  41599: 6da8a00
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 931731123a103cfb3f70ac4b7abfc71d94ba1f03
+refs/heads/master: 60361be1be7854cbffb6dc268d1bc094da33431c

trunk/net/dccp/dccp.h

@@ -40,12 +40,18 @@ extern void dccp_tw_deschedule(struct inet_timewait_sock *tw);
 
 extern void dccp_time_wait(struct sock *sk, int state, int timeo);
 
-/* FIXME: Right size this */
-#define DCCP_MAX_OPT_LEN 128
-
-#define DCCP_MAX_PACKET_HDR 32
-
-#define MAX_DCCP_HEADER  (DCCP_MAX_PACKET_HDR + DCCP_MAX_OPT_LEN + MAX_HEADER)
+/*
+ *  Set safe upper bounds for header and option length. Since Data Offset is 8
+ *  bits (RFC 4340, sec. 5.1), the total header length can never be more than
+ *  4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
+ *    - DCCP-Response with ACK Subheader and 4 bytes of Service code      OR
+ *    - DCCP-Reset    with ACK Subheader and 4 bytes of Reset Code fields
+ *  Hence a safe upper bound for the maximum option length is 1020-28 = 992
+ */
+#define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(int))
+#define DCCP_MAX_PACKET_HDR 28
+#define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
+#define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)
 
 #define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
 				     * state, about 60 seconds */