Add IPv6 Handling for DSCP Policies and Support Interfaces with MAC Addresses

Add bpf functionality to handle IPv6 packets and apply
DSCP value.
Also support DSCP policy rules on multiple interfaces
simultaneously.

Test: atest DscpPolicyTest

Bug: 217166486
Change-Id: I452a87355fd0382a4c38b84aa3465505951d9bf0
diff --git a/bpf_progs/dscp_policy.h b/bpf_progs/dscp_policy.h
new file mode 100644
index 0000000..777c4ff
--- /dev/null
+++ b/bpf_progs/dscp_policy.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define MAX_POLICIES 16
+#define MAP_A 1
+#define MAP_B 2
+
+#define SRC_IP_MASK_FLAG     1
+#define DST_IP_MASK_FLAG     2
+#define SRC_PORT_MASK_FLAG   4
+#define DST_PORT_MASK_FLAG   8
+#define PROTO_MASK_FLAG      16
+
+#define STRUCT_SIZE(name, size) _Static_assert(sizeof(name) == (size), "Incorrect struct size.")
+
+#ifndef v6_equal
+#define v6_equal(a, b)    (a.s6_addr32[0] == b.s6_addr32[0] && \
+                 a.s6_addr32[1] == b.s6_addr32[1] && \
+                 a.s6_addr32[2] == b.s6_addr32[2] && \
+                 a.s6_addr32[3] == b.s6_addr32[3])
+#endif
+
+// TODO: these are already defined in packages/modules/Connectivity/bpf_progs/bpf_net_helpers.h.
+// smove to common location in future.
+static uint64_t (*bpf_get_socket_cookie)(struct __sk_buff* skb) =
+        (void*)BPF_FUNC_get_socket_cookie;
+static int (*bpf_skb_store_bytes)(struct __sk_buff* skb, __u32 offset, const void* from, __u32 len,
+                                  __u64 flags) = (void*)BPF_FUNC_skb_store_bytes;
+static int (*bpf_l3_csum_replace)(struct __sk_buff* skb, __u32 offset, __u64 from, __u64 to,
+                                  __u64 flags) = (void*)BPF_FUNC_l3_csum_replace;
+static long (*bpf_skb_ecn_set_ce)(struct __sk_buff* skb) =
+        (void*)BPF_FUNC_skb_ecn_set_ce;
+
+typedef struct {
+    struct in6_addr srcIp;
+    struct in6_addr dstIp;
+    uint32_t ifindex;
+    __be16 srcPort;
+    __be16 dstPortStart;
+    __be16 dstPortEnd;
+    uint8_t proto;
+    uint8_t dscpVal;
+    uint8_t presentFields;
+    uint8_t pad[3];
+} DscpPolicy;
+STRUCT_SIZE(DscpPolicy, 2 * 16 + 4 + 3 * 2 + 3 * 1 + 3);  // 48
+
+typedef struct {
+    struct in6_addr srcIp;
+    struct in6_addr dstIp;
+    __u32 ifindex;
+    __be16 srcPort;
+    __be16 dstPort;
+    __u8 proto;
+    __u8 dscpVal;
+    __u8 pad[2];
+} RuleEntry;
+STRUCT_SIZE(RuleEntry, 2 * 16 + 1 * 4 + 2 * 2 + 2 * 1 + 2);  // 44
\ No newline at end of file