commit 24602949746ccf56f0ec6efca7732812020b5343
author Maciej Żenczykowski <maze@google.com> Wed Mar 08 03:24:41 2023 +0000
committer Maciej Żenczykowski <maze@google.com> Tue Mar 14 00:50:18 2023 +0000
tree 1c947eea53c20d557030e118754f355a4270252a
parent 9fd65dc81a78c6d12dfe0eaa7f70b905a73a6343

clat: use AF_PACKET/SOCK_RAW not SOCK_DGRAM sockets

This switches incoming packets from L3 to L2,
ie. they now include the ethernet header for non-rawip cases
(like wifi)

Note: depends on userspace clatd change to offset packet
processing index by tpacket_auxdata->tp_net L3 header offset,
an increase in the read buffer size,  and on change to use
IPv6 header relative cBPF for ingress packet filtering!

Test: TreeHugger, atest libclat_test, ping 1.1.1.1 on v6-only wifi
Bug: 265591307
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ie5893d18b0dd796751f95150680a0d4cd5f64c3c

service/jni/com_android_server_connectivity_ClatCoordinator.cpp

diff --git a/service/jni/com_android_server_connectivity_ClatCoordinator.cpp b/service/jni/com_android_server_connectivity_ClatCoordinator.cpp
index 5b42659..dae45f3 100644
--- a/service/jni/com_android_server_connectivity_ClatCoordinator.cpp
+++ b/service/jni/com_android_server_connectivity_ClatCoordinator.cpp
@@ -177,7 +177,7 @@
                                                                               jobject clazz) {
     // Will eventually be bound to htons(ETH_P_IPV6) protocol,
     // but only after appropriate bpf filter is attached.
-    int sock = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
+    const int sock = socket(AF_PACKET, SOCK_RAW | SOCK_CLOEXEC, 0);
     if (sock < 0) {
         throwIOException(env, "packet socket failed", errno);
         return -1;

service/native/libs/libclat/clatutils_test.cpp

diff --git a/service/native/libs/libclat/clatutils_test.cpp b/service/native/libs/libclat/clatutils_test.cpp
index abd4e81..f4f97db 100644
--- a/service/native/libs/libclat/clatutils_test.cpp
+++ b/service/native/libs/libclat/clatutils_test.cpp
@@ -165,7 +165,7 @@
     TunInterface v6Iface;
     ASSERT_EQ(0, v6Iface.init());
 
-    int s = socket(AF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, htons(ETH_P_IPV6));
+    const int s = socket(AF_PACKET, SOCK_RAW | SOCK_CLOEXEC, htons(ETH_P_IPV6));
     EXPECT_LE(0, s);
     struct in6_addr addr6;
     EXPECT_EQ(1, inet_pton(AF_INET6, "2001:db8::f00", &addr6));