MINOR: quic: refactor quic CID association with threads
Do not use an extra DCID parameter on new_quic_cid to be able to
associated a new generated CID to a thread ID. Simply do the computation
inside the function. The API is cleaner this way.
This also has the effects to improve the apparent randomness of CIDs.
With the previous version the first byte of all CIDs are identical for a
connection which could lead to privacy issue. This version may not be
totally perfect on this aspect but it improves the situation.
diff --git a/include/haproxy/xprt_quic.h b/include/haproxy/xprt_quic.h
index d8f23bd..4107fbe 100644
--- a/include/haproxy/xprt_quic.h
+++ b/include/haproxy/xprt_quic.h
@@ -132,12 +132,6 @@
chunk_appendf(buf, ")");
}
-/* Simply compute a thread ID from a CID */
-static inline unsigned long quic_get_cid_tid(const unsigned char *cid)
-{
- return *cid % global.nbthread;
-}
-
/* Free the CIDs attached to <conn> QUIC connection. This must be called under
* the CID lock.
*/
@@ -177,13 +171,32 @@
to->stateless_reset_token = src->stateless_reset_token;
}
+/* Retrieve the associated thread ID for <cid>. */
+static inline unsigned long quic_get_cid_tid(const unsigned char *cid)
+{
+ return *cid % global.nbthread;
+}
+
+/* Modify <cid> to have a CID linked to the thread ID <target_tid>. This is
+ * based on quic_get_cid_tid.
+ */
+static inline void quic_pin_cid_to_tid(unsigned char *cid, int target_tid)
+{
+ cid[0] = cid[0] - (cid[0] % global.nbthread) + target_tid;
+}
+
/* Allocate a new CID with <seq_num> as sequence number and attach it to <root>
* ebtree.
+ *
+ * The CID is randomly generated in part with the result altered to be
+ * associated with the current thread ID. This means this function must only
+ * be called by the quic_conn thread.
+ *
* Returns the new CID if succeeded, NULL if not.
*/
static inline struct quic_connection_id *new_quic_cid(struct eb_root *root,
struct quic_conn *qc,
- int seq_num, unsigned char *dcid)
+ int seq_num)
{
struct quic_connection_id *cid;
@@ -199,8 +212,7 @@
goto err;
}
- /* Set the same first octet from <dcid> */
- cid->cid.data[0] = *dcid;
+ quic_pin_cid_to_tid(cid->cid.data, tid);
cid->qc = qc;
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index caea3e6..a1fa7db 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -2806,7 +2806,7 @@
if (!frm)
goto err;
- cid = new_quic_cid(&qc->cids, qc, i, qc->scid.data);
+ cid = new_quic_cid(&qc->cids, qc, i);
if (!cid)
goto err;
@@ -3605,7 +3605,7 @@
/* Initialize the output buffer */
qc->obuf.pos = qc->obuf.data;
- icid = new_quic_cid(&qc->cids, qc, 0, dcid);
+ icid = new_quic_cid(&qc->cids, qc, 0);
if (!icid) {
TRACE_PROTO("Could not allocate a new connection ID", QUIC_EV_CONN_INIT, qc);
goto err;