Implement Broadcast support

This change adds support for the SO_BROADCAST socket option in gVisor Netstack.
This support includes getsockopt()/setsockopt() functionality for both UDP and
TCP endpoints (the latter being a NOOP), dispatching broadcast messages up and
down the stack, and route finding/creation for broadcast packets. Finally, a
suite of tests have been implemented, exercising this functionality through the
Linux syscall API.

PiperOrigin-RevId: 234850781
Change-Id: If3e666666917d39f55083741c78314a06defb26c

1 files changed, 69 insertions, 0 deletions

diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index 9da5204c1..beece8930 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -148,6 +148,7 @@ cc_library(
     hdrs = ["ip_socket_test_util.h"],
     deps = [
         ":socket_test_util",
+        "@com_google_absl//absl/strings",
     ],
 )
 
@@ -1970,6 +1971,42 @@ cc_library(
     alwayslink = 1,
 )
 
+cc_library(
+    name = "socket_ipv4_udp_unbound_external_networking_test_cases",
+    testonly = 1,
+    srcs = [
+        "socket_ipv4_udp_unbound_external_networking.cc",
+    ],
+    hdrs = [
+        "socket_ipv4_udp_unbound_external_networking.h",
+    ],
+    deps = [
+        ":ip_socket_test_util",
+        ":socket_test_util",
+        "//test/util:test_util",
+        "@com_google_googletest//:gtest",
+    ],
+    alwayslink = 1,
+)
+
+cc_library(
+    name = "socket_ipv4_tcp_unbound_external_networking_test_cases",
+    testonly = 1,
+    srcs = [
+        "socket_ipv4_tcp_unbound_external_networking.cc",
+    ],
+    hdrs = [
+        "socket_ipv4_tcp_unbound_external_networking.h",
+    ],
+    deps = [
+        ":ip_socket_test_util",
+        ":socket_test_util",
+        "//test/util:test_util",
+        "@com_google_googletest//:gtest",
+    ],
+    alwayslink = 1,
+)
+
 cc_binary(
     name = "socket_abstract_test",
     testonly = 1,
@@ -2148,6 +2185,38 @@ cc_binary(
 )
 
 cc_binary(
+    name = "socket_ipv4_udp_unbound_external_networking_test",
+    testonly = 1,
+    srcs = [
+        "socket_ipv4_udp_unbound_external_networking_test.cc",
+    ],
+    linkstatic = 1,
+    deps = [
+        ":ip_socket_test_util",
+        ":socket_ipv4_udp_unbound_external_networking_test_cases",
+        ":socket_test_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "socket_ipv4_tcp_unbound_external_networking_test",
+    testonly = 1,
+    srcs = [
+        "socket_ipv4_tcp_unbound_external_networking_test.cc",
+    ],
+    linkstatic = 1,
+    deps = [
+        ":ip_socket_test_util",
+        ":socket_ipv4_tcp_unbound_external_networking_test_cases",
+        ":socket_test_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
     name = "socket_ip_udp_loopback_non_blocking_test",
     testonly = 1,
     srcs = [