[Cherry-pick] [0.11.0] pd proxy support ipv6 and fix proxy (#4242)

### What this PR does / why we need it?
pd proxy support ipv6, mooncake connector check whether the IPv6 address
is used and notify the user.

---------

Signed-off-by: liziyu <liziyu16@huawei.com>

vllm_ascend/distributed/mooncake/transfer_engine.py

@@ -1,3 +1,4 @@
+import ipaddress
 import threading
 from typing import Optional
 
@@ -8,6 +9,15 @@ _global_te_lock = threading.Lock()
 
 
 def get_global_te(hostname: str, device_name: Optional[str]):
+    try:
+        ip = ipaddress.ip_address(hostname)
+        if isinstance(ip, ipaddress.IPv6Address):
+            raise RuntimeError(
+                "The backend of mooncake's Ascend Direct Xfer Library currently does not support IPv6."
+            )
+    except ValueError:
+        pass
+
     global _global_te
     if _global_te is None:
         with _global_te_lock:

vllm_ascend/envs.py

@@ -162,11 +162,6 @@ env_variables: Dict[str, Callable[[], Any]] = {
     # Whether to enable msMonitor tool to monitor the performance of vllm-ascend.
     "MSMONITOR_USE_DAEMON":
     lambda: bool(int(os.getenv("MSMONITOR_USE_DAEMON", '0'))),
-    # Timeout (in seconds) for delayed KVCache block release. In the prefill
-    # node, if a request is marked for delayed KV block release and the blocks
-    # are not freed within this timeout, they will be forcibly released.
-    "VLLM_ASCEND_KVCACHE_DELAY_FREE_TIMEOUT":
-    lambda: int(os.getenv("VLLM_ASCEND_KVCACHE_DELAY_FREE_TIMEOUT", 250)),
     "VLLM_ASCEND_ENABLE_MLAPO":
     lambda: bool(int(os.getenv("VLLM_ASCEND_ENABLE_MLAPO", '0'))),
     # Whether to enable transpose weight and cast format to FRACTAL_NZ.