IPv6 support (#3949)

Signed-off-by: Brayden Zhong <b8zhong@uwaterloo.ca>

python/sglang/srt/server_args.py

@@ -24,6 +24,7 @@ from typing import List, Optional
 from sglang.srt.hf_transformers_utils import check_gguf_file
 from sglang.srt.reasoning_parser import ReasoningParser
 from sglang.srt.utils import (
+    configure_ipv6,
     get_amdgpu_memory_capacity,
     get_device,
     get_hpu_memory_capacity,
@@ -52,7 +53,7 @@ class ServerArgs:
     dtype: str = "auto"
     kv_cache_dtype: str = "auto"
     quantization: Optional[str] = None
-    quantization_param_path: nullable_str = None
+    quantization_param_path: Optional[str] = None
     context_length: Optional[int] = None
     device: Optional[str] = None
     served_model_name: Optional[str] = None
@@ -140,7 +141,7 @@ class ServerArgs:
 
     # Double Sparsity
     enable_double_sparsity: bool = False
-    ds_channel_config_path: str = None
+    ds_channel_config_path: Optional[str] = None
     ds_heavy_channel_num: int = 32
     ds_heavy_token_num: int = 256
     ds_heavy_channel_type: str = "qk"
@@ -173,7 +174,7 @@ class ServerArgs:
     enable_memory_saver: bool = False
     allow_auto_truncate: bool = False
     enable_custom_logit_processor: bool = False
-    tool_call_parser: str = None
+    tool_call_parser: Optional[str] = None
     enable_hierarchical_cache: bool = False
     hicache_ratio: float = 2.0
     enable_flashinfer_mla: bool = False
@@ -1205,8 +1206,12 @@ class PortArgs:
             # DP attention. Use TCP + port to handle both single-node and multi-node.
             if server_args.nnodes == 1 and server_args.dist_init_addr is None:
                 dist_init_addr = ("127.0.0.1", server_args.port + ZMQ_TCP_PORT_DELTA)
+            elif server_args.dist_init_addr.startswith("["):  # ipv6 address
+                port_num, host = configure_ipv6(server_args.dist_init_addr)
+                dist_init_addr = (host, str(port_num))
             else:
                 dist_init_addr = server_args.dist_init_addr.split(":")
+
             assert (
                 len(dist_init_addr) == 2
             ), "please provide --dist-init-addr as host:port of head node"

python/sglang/srt/utils.py

@@ -1630,6 +1630,38 @@ def is_valid_ipv6_address(address: str) -> bool:
         return False
 
 
+def configure_ipv6(dist_init_addr):
+    addr = dist_init_addr
+    end = addr.find("]")
+    if end == -1:
+        raise ValueError("invalid IPv6 address format: missing ']'")
+
+    host = addr[: end + 1]
+
+    # this only validates the address without brackets: we still need the below checks.
+    # if it's invalid, immediately raise an error so we know it's not formatting issues.
+    if not is_valid_ipv6_address(host[1:end]):
+        raise ValueError(f"invalid IPv6 address: {host}")
+
+    port_str = None
+    if len(addr) > end + 1:
+        if addr[end + 1] == ":":
+            port_str = addr[end + 2 :]
+        else:
+            raise ValueError("received IPv6 address format: expected ':' after ']'")
+
+    if not port_str:
+        raise ValueError(
+            "a port must be specified in IPv6 address (format: [ipv6]:port)"
+        )
+
+    try:
+        port = int(port_str)
+    except ValueError:
+        raise ValueError(f"invalid port in IPv6 address: '{port_str}'")
+    return port, host
+
+
 def rank0_print(msg: str):
     from sglang.srt.distributed import get_tensor_model_parallel_rank