Extract common nested LinkEndpoint pattern

... and unify logic for detached netsted endpoints.

sniffer.go caused crashes if a packet delivery is attempted when the dispatcher
is nil.

Extracted the endpoint nesting logic into a common composable type so it can be
used by the Fuchsia Netstack (the pattern is widespread there).

PiperOrigin-RevId: 317682842

1 files changed, 31 insertions, 0 deletions

diff --git a/pkg/tcpip/link/nested/BUILD b/pkg/tcpip/link/nested/BUILD
new file mode 100644
index 000000000..bdd5276ad
--- /dev/null
+++ b/pkg/tcpip/link/nested/BUILD
@@ -0,0 +1,31 @@
+load("//tools:defs.bzl", "go_library", "go_test")
+
+package(licenses = ["notice"])
+
+go_library(
+    name = "nested",
+    srcs = [
+        "nested.go",
+    ],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//pkg/sync",
+        "//pkg/tcpip",
+        "//pkg/tcpip/buffer",
+        "//pkg/tcpip/stack",
+    ],
+)
+
+go_test(
+    name = "nested_test",
+    size = "small",
+    srcs = [
+        "nested_test.go",
+    ],
+    deps = [
+        "//pkg/tcpip",
+        "//pkg/tcpip/header",
+        "//pkg/tcpip/link/nested",
+        "//pkg/tcpip/stack",
+    ],
+)