[core] Add support for vsock transport

BUILD

@@ -1287,6 +1287,7 @@ grpc_cc_library(
         "//src/core:lib/iomgr/tcp_windows.cc",
         "//src/core:lib/iomgr/unix_sockets_posix.cc",
         "//src/core:lib/iomgr/unix_sockets_posix_noop.cc",
+        "//src/core:lib/iomgr/vsock.cc",
         "//src/core:lib/iomgr/wakeup_fd_eventfd.cc",
         "//src/core:lib/iomgr/wakeup_fd_nospecial.cc",
         "//src/core:lib/iomgr/wakeup_fd_pipe.cc",
@@ -1386,6 +1387,7 @@ grpc_cc_library(
         "//src/core:lib/iomgr/tcp_server_utils_posix.h",
         "//src/core:lib/iomgr/tcp_windows.h",
         "//src/core:lib/iomgr/unix_sockets_posix.h",
+        "//src/core:lib/iomgr/vsock.h",
         "//src/core:lib/iomgr/wakeup_fd_pipe.h",
         "//src/core:lib/iomgr/wakeup_fd_posix.h",
         "//src/core:lib/resource_quota/api.h",

doc/naming.md

@@ -49,6 +49,12 @@ Most gRPC implementations support the following URI schemes:
     as the first character; the implementation will prepend this null. Do not include
     the null in `abstract_path`.
 
+- `vsock:cid:port` -- VSOCK (Linux systems only)
+  - `cid` is 32-bit Context Identifier (CID). It indicates the source or
+    destination, which is either a virtual machine or the host.
+  - `port` is a 32-bit port number. It differentiates between multiple
+    services running on a single machine.
+
 The following schemes are supported by the gRPC C-core implementation,
 but may not be supported in other languages:
 

src/core/ext/filters/client_channel/http_proxy.cc

@@ -180,6 +180,11 @@ absl::optional<std::string> HttpProxyMapper::MapName(
             std::string(server_uri).c_str());
     return absl::nullopt;
   }
+  if (uri->scheme() == "vsock") {
+    gpr_log(GPR_INFO, "not using proxy for VSock '%s'",
+            std::string(server_uri).c_str());
+    return absl::nullopt;
+  }
   // Prefer using 'no_grpc_proxy'. Fallback on 'no_proxy' if it is not set.
   auto no_proxy_str = GetEnv("no_grpc_proxy");
   if (!no_proxy_str.has_value()) {

src/core/ext/filters/client_channel/resolver/sockaddr/README.md

@@ -1 +1 @@
-Support for resolving ipv4:, ipv6:, unix: schemes
+Support for resolving ipv4:, ipv6:, unix:, vsock: schemes

src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc

@@ -172,6 +172,26 @@ class UnixAbstractResolverFactory : public ResolverFactory {
 };
 #endif  // GRPC_HAVE_UNIX_SOCKET
 
+#ifdef GRPC_HAVE_VSOCK
+class VSockResolverFactory : public ResolverFactory {
+ public:
+  bool IsValidUri(const URI& uri) const override {
+    return ParseUri(uri, grpc_parse_vsock, nullptr);
+  }
+
+  OrphanablePtr<Resolver> CreateResolver(ResolverArgs args) const override {
+    return CreateSockaddrResolver(std::move(args), grpc_parse_vsock);
+  }
+
+  std::string GetDefaultAuthority(const URI& /*uri*/) const override {
+    return "localhost";
+  }
+
+  absl::string_view scheme() const override { return "vsock"; }
+};
+
+#endif  // GRPC_HAVE_VSOCK
+
 }  // namespace
 
 void RegisterSockaddrResolver(CoreConfiguration::Builder* builder) {
@@ -185,6 +205,10 @@ void RegisterSockaddrResolver(CoreConfiguration::Builder* builder) {
   builder->resolver_registry()->RegisterResolverFactory(
       std::make_unique<UnixAbstractResolverFactory>());
 #endif
+#ifdef GRPC_HAVE_VSOCK
+  builder->resolver_registry()->RegisterResolverFactory(
+      std::make_unique<VSockResolverFactory>());
+#endif
 }
 
 }  // namespace grpc_core

src/core/ext/transport/chttp2/server/chttp2_server.cc

@@ -71,6 +71,7 @@
 #include "src/core/lib/iomgr/resolved_address.h"
 #include "src/core/lib/iomgr/tcp_server.h"
 #include "src/core/lib/iomgr/unix_sockets_posix.h"
+#include "src/core/lib/iomgr/vsock.h"
 #include "src/core/lib/resource_quota/memory_quota.h"
 #include "src/core/lib/resource_quota/resource_quota.h"
 #include "src/core/lib/security/credentials/credentials.h"
@@ -98,6 +99,7 @@ using ::grpc_event_engine::experimental::EventEngine;
 
 const char kUnixUriPrefix[] = "unix:";
 const char kUnixAbstractUriPrefix[] = "unix-abstract:";
+const char kVSockUriPrefix[] = "vsock:";
 
 class Chttp2ServerListener : public Server::ListenerInterface {
  public:
@@ -941,6 +943,8 @@ grpc_error_handle Chttp2ServerAddPort(Server* server, const char* addr,
                                    kUnixAbstractUriPrefix)) {
       resolved_or =
           grpc_resolve_unix_abstract_domain_address(parsed_addr_unprefixed);
+    } else if (absl::ConsumePrefix(&parsed_addr_unprefixed, kVSockUriPrefix)) {
+      resolved_or = grpc_resolve_vsock_address(parsed_addr_unprefixed);
     } else {
       resolved_or =
           GetDNSResolver()->LookupHostnameBlocking(parsed_addr, "https");