From f27fb07c842639f62ee2a8540783b8d2083d6951 Mon Sep 17 00:00:00 2001
From: gRPC Team Bot <grpc-github-bot@google.com>
Date: Fri, 9 Feb 2024 07:45:43 -0800
Subject: [PATCH] Do not expand unusable v4 addresses.

PiperOrigin-RevId: 605627652
---
 src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.cc | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.cc b/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.cc
index a04f0a36a08..39f233a1079 100644
--- a/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.cc
+++ b/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.cc
@@ -89,6 +89,12 @@ static grpc_error_handle get_unused_port(int* port) {
   return *port <= 0 ? GRPC_ERROR_CREATE("Bad port") : absl::OkStatus();
 }
 
+static bool grpc_is_ipv4_availabile() {
+  const int fd = socket(AF_INET, SOCK_DGRAM, 0);
+  if (fd >= 0) close(fd);
+  return fd >= 0;
+}
+
 grpc_error_handle grpc_tcp_server_add_all_local_addrs(grpc_tcp_server* s,
                                                       unsigned port_index,
                                                       int requested_port,
@@ -110,6 +116,9 @@ grpc_error_handle grpc_tcp_server_add_all_local_addrs(grpc_tcp_server* s,
     }
     gpr_log(GPR_DEBUG, "Picked unused port %d", requested_port);
   }
+
+  static bool v4_available = grpc_is_ipv4_availabile();
+
   if (getifaddrs(&ifa) != 0 || ifa == nullptr) {
     return GRPC_OS_ERROR(errno, "getifaddrs");
   }
@@ -121,6 +130,9 @@ grpc_error_handle grpc_tcp_server_add_all_local_addrs(grpc_tcp_server* s,
     if (ifa_it->ifa_addr == nullptr) {
       continue;
     } else if (ifa_it->ifa_addr->sa_family == AF_INET) {
+      if (!v4_available) {
+        continue;
+      }
       addr.len = static_cast<socklen_t>(sizeof(grpc_sockaddr_in));
     } else if (ifa_it->ifa_addr->sa_family == AF_INET6) {
       addr.len = static_cast<socklen_t>(sizeof(grpc_sockaddr_in6));