From 146b53b32f90c1fe21c712f3e685e0bbdb91d1b4 Mon Sep 17 00:00:00 2001
From: Yanmei-Liu <miaoji.lym@alibaba-inc.com>
Date: Tue, 28 Jan 2025 18:38:40 +0800
Subject: [PATCH] [+] add path cids blocked trigger logic.

---
 include/xquic/xqc_errno.h      |  2 ++
 src/transport/xqc_engine.c     | 15 +++++++++++++--
 src/transport/xqc_packet_out.c | 29 +++++++++++++++++++++++++++++
 src/transport/xqc_packet_out.h |  2 ++
 4 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/include/xquic/xqc_errno.h b/include/xquic/xqc_errno.h
index e4292deb..e229da56 100644
--- a/include/xquic/xqc_errno.h
+++ b/include/xquic/xqc_errno.h
@@ -283,6 +283,8 @@ typedef enum {
     XQC_PATH_NO_ERROR                   = 0x0,
     XQC_PATH_APPLICATION_ABANDON        = 0x004150504142414E, /* Path abandon error code: APPLICATION_ABANDON */
     XQC_PATH_RESOURCE_LIMIT_REACHED     = 0x0052534C494D4954, /* Path abandon error code: RESOURCE_LIMIT_REACHED */
+    XQC_PATH_UNSTABLE_INTERFACE         = 0x00554e5f494e5446, /* Path abandon error code: UNSTABLE_INTERFACE */
+    XQC_PATH_NO_CID_AVAILABLE           = 0x004e4f5f4349445f, /* Path abandon error code: NO_CID_AVAILABLE */
 } xqc_multipath_error_t;
 
 #define QPACK_ERR_START 900
diff --git a/src/transport/xqc_engine.c b/src/transport/xqc_engine.c
index 40bbd0d2..75c0e961 100644
--- a/src/transport/xqc_engine.c
+++ b/src/transport/xqc_engine.c
@@ -651,7 +651,7 @@ xqc_engine_process_conn(xqc_connection_t *conn, xqc_usec_t now)
     xqc_log(conn->log, XQC_LOG_DEBUG, "|conn:%p|state:%s|flag:%s|now:%ui|",
             conn, xqc_conn_state_2_str(conn->conn_state), xqc_conn_flag_2_str(conn, conn->conn_flag), now);
 
-    int ret;
+    int ret = 0, rc = 0;
     xqc_bool_t wait_scid, wait_dcid;
 
     xqc_conn_timer_expire(conn, now);
@@ -733,11 +733,22 @@ xqc_engine_process_conn(xqc_connection_t *conn, xqc_usec_t now)
     }
 
     if (conn->enable_multipath) {
+        ret = xqc_conn_get_available_path_id(conn, NULL);
         if ((conn->conn_flag & XQC_CONN_FLAG_MP_WAIT_MP_READY)
-            && xqc_conn_get_available_path_id(conn, NULL) == XQC_OK) 
+            && ret == XQC_OK)
         {
             conn->conn_flag |= XQC_CONN_FLAG_MP_READY_NOTIFY;
             conn->conn_flag &= ~XQC_CONN_FLAG_MP_WAIT_MP_READY;
+        } else if (ret != XQC_OK) {
+            /* not enough cid for new path id */
+            uint64_t path_id = conn->create_path_count;
+            xqc_cid_set_inner_t *dcid_inner_set = xqc_get_path_cid_set(&conn->dcid_set, path_id);
+            if (dcid_inner_set && dcid_inner_set->unused_cnt == 0) {
+                rc = xqc_write_path_cids_blocked_to_packet(conn, path_id);
+                if (rc) {
+                    xqc_log(conn->log, XQC_LOG_WARN, "|xqc_write_path_cids_blocked_to_packet error|ret:%ui|", ret);
+                }
+            }
         }
 
         xqc_log(conn->log, XQC_LOG_DEBUG, "|create_path_count:%ui|remote_max_path_id:%ui|",
diff --git a/src/transport/xqc_packet_out.c b/src/transport/xqc_packet_out.c
index 41832dd5..2f82d75a 100644
--- a/src/transport/xqc_packet_out.c
+++ b/src/transport/xqc_packet_out.c
@@ -1839,6 +1839,35 @@ xqc_write_path_blocked_to_packet(xqc_connection_t *conn, uint64_t max_path_id)
     xqc_log(conn->log, XQC_LOG_DEBUG, "|max_path_id:%ui|", max_path_id);
     return XQC_OK;
 
+    error:
+    xqc_maybe_recycle_packet_out(packet_out, conn);
+    return -XQC_EWRITE_PKT;
+}
+
+
+int
+xqc_write_path_cids_blocked_to_packet(xqc_connection_t *conn, uint64_t path_id)
+{
+    ssize_t ret = XQC_ERROR;
+    xqc_packet_out_t *packet_out;
+    xqc_log(conn->log, XQC_LOG_DEBUG, "|path blocked max_path_id:%ui|", path_id);
+
+    packet_out = xqc_write_new_packet(conn, XQC_PTYPE_SHORT_HEADER);
+    if (packet_out == NULL) {
+        xqc_log(conn->log, XQC_LOG_ERROR, "|xqc_write_new_packet error|");
+        return -XQC_EWRITE_PKT;
+    }
+
+    ret = xqc_gen_path_cids_blocked_frame(packet_out, path_id);
+    if (ret < 0) {
+        xqc_log(conn->log, XQC_LOG_ERROR, "|xqc_gen_path_blocked_frame error|");
+        goto error;
+    }
+    packet_out->po_used_size += ret;
+    xqc_send_queue_move_to_high_pri(&packet_out->po_list, conn->conn_send_queue);
+    xqc_log(conn->log, XQC_LOG_DEBUG, "|max_path_id:%ui|", path_id);
+    return XQC_OK;
+
     error:
     xqc_maybe_recycle_packet_out(packet_out, conn);
     return -XQC_EWRITE_PKT;
diff --git a/src/transport/xqc_packet_out.h b/src/transport/xqc_packet_out.h
index 0168a85c..248a14f5 100644
--- a/src/transport/xqc_packet_out.h
+++ b/src/transport/xqc_packet_out.h
@@ -233,6 +233,8 @@ xqc_int_t xqc_write_mp_retire_conn_id_frame_to_packet(xqc_connection_t *conn, ui
 
 int xqc_write_max_path_id_to_packet(xqc_connection_t *conn, uint64_t max_path_id);
 int xqc_write_path_blocked_to_packet(xqc_connection_t *conn, uint64_t max_path_id);
+int xqc_write_path_cids_blocked_to_packet(xqc_connection_t *conn, uint64_t path_id);
+
 /**
  * @brief Get remained space size in packet out buff.
  *