On 9/22/06, Arnaldo Carvalho de Melo <[EMAIL PROTECTED]> wrote:
On 9/22/06, Gerrit Renker <[EMAIL PROTECTED]> wrote:
> Hi Arnaldo
> | Gerrit, could you please use my net-2.6.19?
> Of course - I didn't know it was active. I have just pulled your tree and
> the patch applies without problem.
OK, going over it now.
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 272e858..9e6344f 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -40,12 +40,17 @@ extern void dccp_tw_deschedule(struct in
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 DCCP_MAX_OPT_LEN 992
+#define DCCP_MAX_PACKET_HDR 28
+#define MAX_DCCP_HEADER (1020 + MAX_HEADER)
With this change DCCP_MAX_PACKET_HDR is not used anywhere, I'm
rewriting it so that we use it to calculate MAX_DCCP_HEADER, something
like:
#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)
Thanks,
- Arnaldo
-
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