diff --git a/Tethering/Android.bp b/Tethering/Android.bp
index 3c49383..55ea3f9 100644
--- a/Tethering/Android.bp
+++ b/Tethering/Android.bp
@@ -94,7 +94,7 @@
     min_sdk_version: "30",
     header_libs: [
         "bpf_syscall_wrappers",
-        "bpf_tethering_headers",
+        "bpf_connectivity_headers",
     ],
     srcs: [
         "jni/*.cpp",
diff --git a/Tethering/bpf_progs/Android.bp b/Tethering/bpf_progs/Android.bp
deleted file mode 100644
index 5b00dfe..0000000
--- a/Tethering/bpf_progs/Android.bp
+++ /dev/null
@@ -1,60 +0,0 @@
-//
-// Copyright (C) 2020 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.
-//
-
-//
-// struct definitions shared with JNI
-//
-package {
-    default_applicable_licenses: ["Android-Apache-2.0"],
-}
-
-cc_library_headers {
-    name: "bpf_tethering_headers",
-    vendor_available: false,
-    host_supported: false,
-    export_include_dirs: ["."],
-    cflags: [
-        "-Wall",
-        "-Werror",
-    ],
-    sdk_version: "30",
-    min_sdk_version: "30",
-    apex_available: ["com.android.tethering"],
-    visibility: [
-        "//packages/modules/Connectivity/Tethering",
-    ],
-}
-
-//
-// bpf kernel programs
-//
-bpf {
-    name: "offload.o",
-    srcs: ["offload.c"],
-    cflags: [
-        "-Wall",
-        "-Werror",
-    ],
-}
-
-bpf {
-    name: "test.o",
-    srcs: ["test.c"],
-    cflags: [
-        "-Wall",
-        "-Werror",
-    ],
-}
diff --git a/Tethering/bpf_progs/bpf_net_helpers.h b/Tethering/bpf_progs/bpf_net_helpers.h
deleted file mode 100644
index c798580..0000000
--- a/Tethering/bpf_progs/bpf_net_helpers.h
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- * Copyright (C) 2019 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.
- */
-
-#pragma once
-
-#include <linux/bpf.h>
-#include <linux/if_packet.h>
-#include <stdbool.h>
-#include <stdint.h>
-
-// this returns 0 iff skb->sk is NULL
-static uint64_t (*bpf_get_socket_cookie)(struct __sk_buff* skb) = (void*)BPF_FUNC_get_socket_cookie;
-
-static uint32_t (*bpf_get_socket_uid)(struct __sk_buff* skb) = (void*)BPF_FUNC_get_socket_uid;
-
-static int (*bpf_skb_pull_data)(struct __sk_buff* skb, __u32 len) = (void*)BPF_FUNC_skb_pull_data;
-
-static int (*bpf_skb_load_bytes)(struct __sk_buff* skb, int off, void* to,
-                                 int len) = (void*)BPF_FUNC_skb_load_bytes;
-
-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 int64_t (*bpf_csum_diff)(__be32* from, __u32 from_size, __be32* to, __u32 to_size,
-                                __wsum seed) = (void*)BPF_FUNC_csum_diff;
-
-static int64_t (*bpf_csum_update)(struct __sk_buff* skb, __wsum csum) = (void*)BPF_FUNC_csum_update;
-
-static int (*bpf_skb_change_proto)(struct __sk_buff* skb, __be16 proto,
-                                   __u64 flags) = (void*)BPF_FUNC_skb_change_proto;
-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 int (*bpf_l4_csum_replace)(struct __sk_buff* skb, __u32 offset, __u64 from, __u64 to,
-                                  __u64 flags) = (void*)BPF_FUNC_l4_csum_replace;
-static int (*bpf_redirect)(__u32 ifindex, __u64 flags) = (void*)BPF_FUNC_redirect;
-static int (*bpf_redirect_map)(const struct bpf_map_def* map, __u32 key,
-                               __u64 flags) = (void*)BPF_FUNC_redirect_map;
-
-static int (*bpf_skb_change_head)(struct __sk_buff* skb, __u32 head_room,
-                                  __u64 flags) = (void*)BPF_FUNC_skb_change_head;
-static int (*bpf_skb_adjust_room)(struct __sk_buff* skb, __s32 len_diff, __u32 mode,
-                                  __u64 flags) = (void*)BPF_FUNC_skb_adjust_room;
-
-// Android only supports little endian architectures
-#define htons(x) (__builtin_constant_p(x) ? ___constant_swab16(x) : __builtin_bswap16(x))
-#define htonl(x) (__builtin_constant_p(x) ? ___constant_swab32(x) : __builtin_bswap32(x))
-#define ntohs(x) htons(x)
-#define ntohl(x) htonl(x)
-
-static inline __always_inline __unused bool is_received_skb(struct __sk_buff* skb) {
-    return skb->pkt_type == PACKET_HOST || skb->pkt_type == PACKET_BROADCAST ||
-           skb->pkt_type == PACKET_MULTICAST;
-}
-
-// try to make the first 'len' header bytes readable via direct packet access
-static inline __always_inline void try_make_readable(struct __sk_buff* skb, int len) {
-    if (len > skb->len) len = skb->len;
-    if (skb->data_end - skb->data < len) bpf_skb_pull_data(skb, len);
-}
diff --git a/Tethering/bpf_progs/bpf_tethering.h b/Tethering/bpf_progs/bpf_tethering.h
deleted file mode 100644
index 5fdf8cd..0000000
--- a/Tethering/bpf_progs/bpf_tethering.h
+++ /dev/null
@@ -1,217 +0,0 @@
-/*
- * Copyright (C) 2021 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.
- */
-
-#pragma once
-
-#include <linux/if.h>
-#include <linux/if_ether.h>
-#include <linux/in.h>
-#include <linux/in6.h>
-
-// Common definitions for BPF code in the tethering mainline module.
-// These definitions are available to:
-// - The BPF programs in Tethering/bpf_progs/
-// - JNI code that depends on the bpf_tethering_headers library.
-
-#define BPF_TETHER_ERRORS    \
-    ERR(INVALID_IP_VERSION)  \
-    ERR(LOW_TTL)             \
-    ERR(INVALID_TCP_HEADER)  \
-    ERR(TCP_CONTROL_PACKET)  \
-    ERR(NON_GLOBAL_SRC)      \
-    ERR(NON_GLOBAL_DST)      \
-    ERR(LOCAL_SRC_DST)       \
-    ERR(NO_STATS_ENTRY)      \
-    ERR(NO_LIMIT_ENTRY)      \
-    ERR(BELOW_IPV4_MTU)      \
-    ERR(BELOW_IPV6_MTU)      \
-    ERR(LIMIT_REACHED)       \
-    ERR(CHANGE_HEAD_FAILED)  \
-    ERR(TOO_SHORT)           \
-    ERR(HAS_IP_OPTIONS)      \
-    ERR(IS_IP_FRAG)          \
-    ERR(CHECKSUM)            \
-    ERR(NON_TCP_UDP)         \
-    ERR(NON_TCP)             \
-    ERR(SHORT_L4_HEADER)     \
-    ERR(SHORT_TCP_HEADER)    \
-    ERR(SHORT_UDP_HEADER)    \
-    ERR(UDP_CSUM_ZERO)       \
-    ERR(TRUNCATED_IPV4)      \
-    ERR(_MAX)
-
-#define ERR(x) BPF_TETHER_ERR_ ##x,
-enum {
-    BPF_TETHER_ERRORS
-};
-#undef ERR
-
-#define ERR(x) #x,
-static const char *bpf_tether_errors[] = {
-    BPF_TETHER_ERRORS
-};
-#undef ERR
-
-// This header file is shared by eBPF kernel programs (C) and netd (C++) and
-// some of the maps are also accessed directly from Java mainline module code.
-//
-// Hence: explicitly pad all relevant structures and assert that their size
-// is the sum of the sizes of their fields.
-#define STRUCT_SIZE(name, size) _Static_assert(sizeof(name) == (size), "Incorrect struct size.")
-
-
-#define BPF_PATH_TETHER BPF_PATH "tethering/"
-
-#define TETHER_STATS_MAP_PATH BPF_PATH_TETHER "map_offload_tether_stats_map"
-
-typedef uint32_t TetherStatsKey;  // upstream ifindex
-
-typedef struct {
-    uint64_t rxPackets;
-    uint64_t rxBytes;
-    uint64_t rxErrors;
-    uint64_t txPackets;
-    uint64_t txBytes;
-    uint64_t txErrors;
-} TetherStatsValue;
-STRUCT_SIZE(TetherStatsValue, 6 * 8);  // 48
-
-#define TETHER_LIMIT_MAP_PATH BPF_PATH_TETHER "map_offload_tether_limit_map"
-
-typedef uint32_t TetherLimitKey;    // upstream ifindex
-typedef uint64_t TetherLimitValue;  // in bytes
-
-#define TETHER_DOWNSTREAM6_TC_PROG_RAWIP_NAME "prog_offload_schedcls_tether_downstream6_rawip"
-#define TETHER_DOWNSTREAM6_TC_PROG_ETHER_NAME "prog_offload_schedcls_tether_downstream6_ether"
-
-#define TETHER_DOWNSTREAM6_TC_PROG_RAWIP_PATH BPF_PATH_TETHER TETHER_DOWNSTREAM6_TC_PROG_RAWIP_NAME
-#define TETHER_DOWNSTREAM6_TC_PROG_ETHER_PATH BPF_PATH_TETHER TETHER_DOWNSTREAM6_TC_PROG_ETHER_NAME
-
-#define TETHER_DOWNSTREAM6_MAP_PATH BPF_PATH_TETHER "map_offload_tether_downstream6_map"
-
-// For now tethering offload only needs to support downstreams that use 6-byte MAC addresses,
-// because all downstream types that are currently supported (WiFi, USB, Bluetooth and
-// Ethernet) have 6-byte MAC addresses.
-
-typedef struct {
-    uint32_t iif;              // The input interface index
-    uint8_t dstMac[ETH_ALEN];  // destination ethernet mac address (zeroed iff rawip ingress)
-    uint8_t zero[2];           // zero pad for 8 byte alignment
-    struct in6_addr neigh6;    // The destination IPv6 address
-} TetherDownstream6Key;
-STRUCT_SIZE(TetherDownstream6Key, 4 + 6 + 2 + 16);  // 28
-
-typedef struct {
-    uint32_t oif;             // The output interface to redirect to
-    struct ethhdr macHeader;  // includes dst/src mac and ethertype (zeroed iff rawip egress)
-    uint16_t pmtu;            // The maximum L3 output path/route mtu
-} Tether6Value;
-STRUCT_SIZE(Tether6Value, 4 + 14 + 2);  // 20
-
-#define TETHER_DOWNSTREAM64_MAP_PATH BPF_PATH_TETHER "map_offload_tether_downstream64_map"
-
-typedef struct {
-    uint32_t iif;              // The input interface index
-    uint8_t dstMac[ETH_ALEN];  // destination ethernet mac address (zeroed iff rawip ingress)
-    uint16_t l4Proto;          // IPPROTO_TCP/UDP/...
-    struct in6_addr src6;      // source &
-    struct in6_addr dst6;      // destination IPv6 addresses
-    __be16 srcPort;            // source &
-    __be16 dstPort;            // destination tcp/udp/... ports
-} TetherDownstream64Key;
-STRUCT_SIZE(TetherDownstream64Key, 4 + 6 + 2 + 16 + 16 + 2 + 2);  // 48
-
-typedef struct {
-    uint32_t oif;             // The output interface to redirect to
-    struct ethhdr macHeader;  // includes dst/src mac and ethertype (zeroed iff rawip egress)
-    uint16_t pmtu;            // The maximum L3 output path/route mtu
-    struct in_addr src4;      // source &
-    struct in_addr dst4;      // destination IPv4 addresses
-    __be16 srcPort;           // source &
-    __be16 outPort;           // destination tcp/udp/... ports
-    uint64_t lastUsed;        // Kernel updates on each use with bpf_ktime_get_boot_ns()
-} TetherDownstream64Value;
-STRUCT_SIZE(TetherDownstream64Value, 4 + 14 + 2 + 4 + 4 + 2 + 2 + 8);  // 40
-
-#define TETHER_UPSTREAM6_TC_PROG_RAWIP_NAME "prog_offload_schedcls_tether_upstream6_rawip"
-#define TETHER_UPSTREAM6_TC_PROG_ETHER_NAME "prog_offload_schedcls_tether_upstream6_ether"
-
-#define TETHER_UPSTREAM6_TC_PROG_RAWIP_PATH BPF_PATH_TETHER TETHER_UPSTREAM6_TC_PROG_RAWIP_NAME
-#define TETHER_UPSTREAM6_TC_PROG_ETHER_PATH BPF_PATH_TETHER TETHER_UPSTREAM6_TC_PROG_ETHER_NAME
-
-#define TETHER_UPSTREAM6_MAP_PATH BPF_PATH_TETHER "map_offload_tether_upstream6_map"
-
-typedef struct {
-    uint32_t iif;              // The input interface index
-    uint8_t dstMac[ETH_ALEN];  // destination ethernet mac address (zeroed iff rawip ingress)
-    uint8_t zero[2];           // zero pad for 8 byte alignment
-                               // TODO: extend this to include src ip /64 subnet
-} TetherUpstream6Key;
-STRUCT_SIZE(TetherUpstream6Key, 12);
-
-#define TETHER_DOWNSTREAM4_TC_PROG_RAWIP_NAME "prog_offload_schedcls_tether_downstream4_rawip"
-#define TETHER_DOWNSTREAM4_TC_PROG_ETHER_NAME "prog_offload_schedcls_tether_downstream4_ether"
-
-#define TETHER_DOWNSTREAM4_TC_PROG_RAWIP_PATH BPF_PATH_TETHER TETHER_DOWNSTREAM4_TC_PROG_RAWIP_NAME
-#define TETHER_DOWNSTREAM4_TC_PROG_ETHER_PATH BPF_PATH_TETHER TETHER_DOWNSTREAM4_TC_PROG_ETHER_NAME
-
-#define TETHER_DOWNSTREAM4_MAP_PATH BPF_PATH_TETHER "map_offload_tether_downstream4_map"
-
-
-#define TETHER_UPSTREAM4_TC_PROG_RAWIP_NAME "prog_offload_schedcls_tether_upstream4_rawip"
-#define TETHER_UPSTREAM4_TC_PROG_ETHER_NAME "prog_offload_schedcls_tether_upstream4_ether"
-
-#define TETHER_UPSTREAM4_TC_PROG_RAWIP_PATH BPF_PATH_TETHER TETHER_UPSTREAM4_TC_PROG_RAWIP_NAME
-#define TETHER_UPSTREAM4_TC_PROG_ETHER_PATH BPF_PATH_TETHER TETHER_UPSTREAM4_TC_PROG_ETHER_NAME
-
-#define TETHER_UPSTREAM4_MAP_PATH BPF_PATH_TETHER "map_offload_tether_upstream4_map"
-
-typedef struct {
-    uint32_t iif;              // The input interface index
-    uint8_t dstMac[ETH_ALEN];  // destination ethernet mac address (zeroed iff rawip ingress)
-    uint16_t l4Proto;          // IPPROTO_TCP/UDP/...
-    struct in_addr src4;       // source &
-    struct in_addr dst4;       // destination IPv4 addresses
-    __be16 srcPort;            // source &
-    __be16 dstPort;            // destination TCP/UDP/... ports
-} Tether4Key;
-STRUCT_SIZE(Tether4Key, 4 + 6 + 2 + 4 + 4 + 2 + 2);  // 24
-
-typedef struct {
-    uint32_t oif;             // The output interface to redirect to
-    struct ethhdr macHeader;  // includes dst/src mac and ethertype (zeroed iff rawip egress)
-    uint16_t pmtu;            // Maximum L3 output path/route mtu
-    struct in6_addr src46;    // source &                 (always IPv4 mapped for downstream)
-    struct in6_addr dst46;    // destination IP addresses (may be IPv4 mapped or IPv6 for upstream)
-    __be16 srcPort;           // source &
-    __be16 dstPort;           // destination tcp/udp/... ports
-    uint64_t last_used;       // Kernel updates on each use with bpf_ktime_get_boot_ns()
-} Tether4Value;
-STRUCT_SIZE(Tether4Value, 4 + 14 + 2 + 16 + 16 + 2 + 2 + 8);  // 64
-
-#define TETHER_DOWNSTREAM_XDP_PROG_RAWIP_NAME "prog_offload_xdp_tether_downstream_rawip"
-#define TETHER_DOWNSTREAM_XDP_PROG_ETHER_NAME "prog_offload_xdp_tether_downstream_ether"
-
-#define TETHER_DOWNSTREAM_XDP_PROG_RAWIP_PATH BPF_PATH_TETHER TETHER_DOWNSTREAM_XDP_PROG_RAWIP_NAME
-#define TETHER_DOWNSTREAM_XDP_PROG_ETHER_PATH BPF_PATH_TETHER TETHER_DOWNSTREAM_XDP_PROG_ETHER_NAME
-
-#define TETHER_UPSTREAM_XDP_PROG_RAWIP_NAME "prog_offload_xdp_tether_upstream_rawip"
-#define TETHER_UPSTREAM_XDP_PROG_ETHER_NAME "prog_offload_xdp_tether_upstream_ether"
-
-#define TETHER_UPSTREAM_XDP_PROG_RAWIP_PATH BPF_PATH_TETHER TETHER_UPSTREAM_XDP_PROG_RAWIP_NAME
-#define TETHER_UPSTREAM_XDP_PROG_ETHER_PATH BPF_PATH_TETHER TETHER_UPSTREAM_XDP_PROG_ETHER_NAME
-
-#undef STRUCT_SIZE
diff --git a/Tethering/bpf_progs/offload.c b/Tethering/bpf_progs/offload.c
deleted file mode 100644
index 977e918..0000000
--- a/Tethering/bpf_progs/offload.c
+++ /dev/null
@@ -1,848 +0,0 @@
-/*
- * Copyright (C) 2020 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.
- */
-
-#include <linux/if.h>
-#include <linux/ip.h>
-#include <linux/ipv6.h>
-#include <linux/pkt_cls.h>
-#include <linux/tcp.h>
-
-// bionic kernel uapi linux/udp.h header is munged...
-#define __kernel_udphdr udphdr
-#include <linux/udp.h>
-
-// The resulting .o needs to load on the Android S bpfloader v0.2
-#define BPFLOADER_MIN_VER 2u
-
-#include "bpf_helpers.h"
-#include "bpf_net_helpers.h"
-#include "bpf_tethering.h"
-
-// From kernel:include/net/ip.h
-#define IP_DF 0x4000  // Flag: "Don't Fragment"
-
-// ----- Helper functions for offsets to fields -----
-
-// They all assume simple IP packets:
-//   - no VLAN ethernet tags
-//   - no IPv4 options (see IPV4_HLEN/TCP4_OFFSET/UDP4_OFFSET)
-//   - no IPv6 extension headers
-//   - no TCP options (see TCP_HLEN)
-
-//#define ETH_HLEN sizeof(struct ethhdr)
-#define IP4_HLEN sizeof(struct iphdr)
-#define IP6_HLEN sizeof(struct ipv6hdr)
-#define TCP_HLEN sizeof(struct tcphdr)
-#define UDP_HLEN sizeof(struct udphdr)
-
-// Offsets from beginning of L4 (TCP/UDP) header
-#define TCP_OFFSET(field) offsetof(struct tcphdr, field)
-#define UDP_OFFSET(field) offsetof(struct udphdr, field)
-
-// Offsets from beginning of L3 (IPv4) header
-#define IP4_OFFSET(field) offsetof(struct iphdr, field)
-#define IP4_TCP_OFFSET(field) (IP4_HLEN + TCP_OFFSET(field))
-#define IP4_UDP_OFFSET(field) (IP4_HLEN + UDP_OFFSET(field))
-
-// Offsets from beginning of L3 (IPv6) header
-#define IP6_OFFSET(field) offsetof(struct ipv6hdr, field)
-#define IP6_TCP_OFFSET(field) (IP6_HLEN + TCP_OFFSET(field))
-#define IP6_UDP_OFFSET(field) (IP6_HLEN + UDP_OFFSET(field))
-
-// Offsets from beginning of L2 (ie. Ethernet) header (which must be present)
-#define ETH_IP4_OFFSET(field) (ETH_HLEN + IP4_OFFSET(field))
-#define ETH_IP4_TCP_OFFSET(field) (ETH_HLEN + IP4_TCP_OFFSET(field))
-#define ETH_IP4_UDP_OFFSET(field) (ETH_HLEN + IP4_UDP_OFFSET(field))
-#define ETH_IP6_OFFSET(field) (ETH_HLEN + IP6_OFFSET(field))
-#define ETH_IP6_TCP_OFFSET(field) (ETH_HLEN + IP6_TCP_OFFSET(field))
-#define ETH_IP6_UDP_OFFSET(field) (ETH_HLEN + IP6_UDP_OFFSET(field))
-
-// ----- Tethering Error Counters -----
-
-DEFINE_BPF_MAP_GRW(tether_error_map, ARRAY, uint32_t, uint32_t, BPF_TETHER_ERR__MAX,
-                   AID_NETWORK_STACK)
-
-#define COUNT_AND_RETURN(counter, ret) do {                     \
-    uint32_t code = BPF_TETHER_ERR_ ## counter;                 \
-    uint32_t *count = bpf_tether_error_map_lookup_elem(&code);  \
-    if (count) __sync_fetch_and_add(count, 1);                  \
-    return ret;                                                 \
-} while(0)
-
-#define TC_DROP(counter) COUNT_AND_RETURN(counter, TC_ACT_SHOT)
-#define TC_PUNT(counter) COUNT_AND_RETURN(counter, TC_ACT_PIPE)
-
-#define XDP_DROP(counter) COUNT_AND_RETURN(counter, XDP_DROP)
-#define XDP_PUNT(counter) COUNT_AND_RETURN(counter, XDP_PASS)
-
-// ----- Tethering Data Stats and Limits -----
-
-// Tethering stats, indexed by upstream interface.
-DEFINE_BPF_MAP_GRW(tether_stats_map, HASH, TetherStatsKey, TetherStatsValue, 16, AID_NETWORK_STACK)
-
-// Tethering data limit, indexed by upstream interface.
-// (tethering allowed when stats[iif].rxBytes + stats[iif].txBytes < limit[iif])
-DEFINE_BPF_MAP_GRW(tether_limit_map, HASH, TetherLimitKey, TetherLimitValue, 16, AID_NETWORK_STACK)
-
-// ----- IPv6 Support -----
-
-DEFINE_BPF_MAP_GRW(tether_downstream6_map, HASH, TetherDownstream6Key, Tether6Value, 64,
-                   AID_NETWORK_STACK)
-
-DEFINE_BPF_MAP_GRW(tether_downstream64_map, HASH, TetherDownstream64Key, TetherDownstream64Value,
-                   1024, AID_NETWORK_STACK)
-
-DEFINE_BPF_MAP_GRW(tether_upstream6_map, HASH, TetherUpstream6Key, Tether6Value, 64,
-                   AID_NETWORK_STACK)
-
-static inline __always_inline int do_forward6(struct __sk_buff* skb, const bool is_ethernet,
-        const bool downstream) {
-    // Must be meta-ethernet IPv6 frame
-    if (skb->protocol != htons(ETH_P_IPV6)) return TC_ACT_PIPE;
-
-    // Require ethernet dst mac address to be our unicast address.
-    if (is_ethernet && (skb->pkt_type != PACKET_HOST)) return TC_ACT_PIPE;
-
-    const int l2_header_size = is_ethernet ? sizeof(struct ethhdr) : 0;
-
-    // Since the program never writes via DPA (direct packet access) auto-pull/unclone logic does
-    // not trigger and thus we need to manually make sure we can read packet headers via DPA.
-    // Note: this is a blind best effort pull, which may fail or pull less - this doesn't matter.
-    // It has to be done early cause it will invalidate any skb->data/data_end derived pointers.
-    try_make_readable(skb, l2_header_size + IP6_HLEN + TCP_HLEN);
-
-    void* data = (void*)(long)skb->data;
-    const void* data_end = (void*)(long)skb->data_end;
-    struct ethhdr* eth = is_ethernet ? data : NULL;  // used iff is_ethernet
-    struct ipv6hdr* ip6 = is_ethernet ? (void*)(eth + 1) : data;
-
-    // Must have (ethernet and) ipv6 header
-    if (data + l2_header_size + sizeof(*ip6) > data_end) return TC_ACT_PIPE;
-
-    // Ethertype - if present - must be IPv6
-    if (is_ethernet && (eth->h_proto != htons(ETH_P_IPV6))) return TC_ACT_PIPE;
-
-    // IP version must be 6
-    if (ip6->version != 6) TC_PUNT(INVALID_IP_VERSION);
-
-    // Cannot decrement during forward if already zero or would be zero,
-    // Let the kernel's stack handle these cases and generate appropriate ICMP errors.
-    if (ip6->hop_limit <= 1) TC_PUNT(LOW_TTL);
-
-    // If hardware offload is running and programming flows based on conntrack entries,
-    // try not to interfere with it.
-    if (ip6->nexthdr == IPPROTO_TCP) {
-        struct tcphdr* tcph = (void*)(ip6 + 1);
-
-        // Make sure we can get at the tcp header
-        if (data + l2_header_size + sizeof(*ip6) + sizeof(*tcph) > data_end)
-            TC_PUNT(INVALID_TCP_HEADER);
-
-        // Do not offload TCP packets with any one of the SYN/FIN/RST flags
-        if (tcph->syn || tcph->fin || tcph->rst) TC_PUNT(TCP_CONTROL_PACKET);
-    }
-
-    // Protect against forwarding packets sourced from ::1 or fe80::/64 or other weirdness.
-    __be32 src32 = ip6->saddr.s6_addr32[0];
-    if (src32 != htonl(0x0064ff9b) &&                        // 64:ff9b:/32 incl. XLAT464 WKP
-        (src32 & htonl(0xe0000000)) != htonl(0x20000000))    // 2000::/3 Global Unicast
-        TC_PUNT(NON_GLOBAL_SRC);
-
-    // Protect against forwarding packets destined to ::1 or fe80::/64 or other weirdness.
-    __be32 dst32 = ip6->daddr.s6_addr32[0];
-    if (dst32 != htonl(0x0064ff9b) &&                        // 64:ff9b:/32 incl. XLAT464 WKP
-        (dst32 & htonl(0xe0000000)) != htonl(0x20000000))    // 2000::/3 Global Unicast
-        TC_PUNT(NON_GLOBAL_DST);
-
-    // In the upstream direction do not forward traffic within the same /64 subnet.
-    if (!downstream && (src32 == dst32) && (ip6->saddr.s6_addr32[1] == ip6->daddr.s6_addr32[1]))
-        TC_PUNT(LOCAL_SRC_DST);
-
-    TetherDownstream6Key kd = {
-            .iif = skb->ifindex,
-            .neigh6 = ip6->daddr,
-    };
-
-    TetherUpstream6Key ku = {
-            .iif = skb->ifindex,
-    };
-    if (is_ethernet) __builtin_memcpy(downstream ? kd.dstMac : ku.dstMac, eth->h_dest, ETH_ALEN);
-
-    Tether6Value* v = downstream ? bpf_tether_downstream6_map_lookup_elem(&kd)
-                                 : bpf_tether_upstream6_map_lookup_elem(&ku);
-
-    // If we don't find any offload information then simply let the core stack handle it...
-    if (!v) return TC_ACT_PIPE;
-
-    uint32_t stat_and_limit_k = downstream ? skb->ifindex : v->oif;
-
-    TetherStatsValue* stat_v = bpf_tether_stats_map_lookup_elem(&stat_and_limit_k);
-
-    // If we don't have anywhere to put stats, then abort...
-    if (!stat_v) TC_PUNT(NO_STATS_ENTRY);
-
-    uint64_t* limit_v = bpf_tether_limit_map_lookup_elem(&stat_and_limit_k);
-
-    // If we don't have a limit, then abort...
-    if (!limit_v) TC_PUNT(NO_LIMIT_ENTRY);
-
-    // Required IPv6 minimum mtu is 1280, below that not clear what we should do, abort...
-    if (v->pmtu < IPV6_MIN_MTU) TC_PUNT(BELOW_IPV6_MTU);
-
-    // Approximate handling of TCP/IPv6 overhead for incoming LRO/GRO packets: default
-    // outbound path mtu of 1500 is not necessarily correct, but worst case we simply
-    // undercount, which is still better then not accounting for this overhead at all.
-    // Note: this really shouldn't be device/path mtu at all, but rather should be
-    // derived from this particular connection's mss (ie. from gro segment size).
-    // This would require a much newer kernel with newer ebpf accessors.
-    // (This is also blindly assuming 12 bytes of tcp timestamp option in tcp header)
-    uint64_t packets = 1;
-    uint64_t bytes = skb->len;
-    if (bytes > v->pmtu) {
-        const int tcp_overhead = sizeof(struct ipv6hdr) + sizeof(struct tcphdr) + 12;
-        const int mss = v->pmtu - tcp_overhead;
-        const uint64_t payload = bytes - tcp_overhead;
-        packets = (payload + mss - 1) / mss;
-        bytes = tcp_overhead * packets + payload;
-    }
-
-    // Are we past the limit?  If so, then abort...
-    // Note: will not overflow since u64 is 936 years even at 5Gbps.
-    // Do not drop here.  Offload is just that, whenever we fail to handle
-    // a packet we let the core stack deal with things.
-    // (The core stack needs to handle limits correctly anyway,
-    // since we don't offload all traffic in both directions)
-    if (stat_v->rxBytes + stat_v->txBytes + bytes > *limit_v) TC_PUNT(LIMIT_REACHED);
-
-    if (!is_ethernet) {
-        // Try to inject an ethernet header, and simply return if we fail.
-        // We do this even if TX interface is RAWIP and thus does not need an ethernet header,
-        // because this is easier and the kernel will strip extraneous ethernet header.
-        if (bpf_skb_change_head(skb, sizeof(struct ethhdr), /*flags*/ 0)) {
-            __sync_fetch_and_add(downstream ? &stat_v->rxErrors : &stat_v->txErrors, 1);
-            TC_PUNT(CHANGE_HEAD_FAILED);
-        }
-
-        // bpf_skb_change_head() invalidates all pointers - reload them
-        data = (void*)(long)skb->data;
-        data_end = (void*)(long)skb->data_end;
-        eth = data;
-        ip6 = (void*)(eth + 1);
-
-        // I do not believe this can ever happen, but keep the verifier happy...
-        if (data + sizeof(struct ethhdr) + sizeof(*ip6) > data_end) {
-            __sync_fetch_and_add(downstream ? &stat_v->rxErrors : &stat_v->txErrors, 1);
-            TC_DROP(TOO_SHORT);
-        }
-    };
-
-    // At this point we always have an ethernet header - which will get stripped by the
-    // kernel during transmit through a rawip interface.  ie. 'eth' pointer is valid.
-    // Additionally note that 'is_ethernet' and 'l2_header_size' are no longer correct.
-
-    // CHECKSUM_COMPLETE is a 16-bit one's complement sum,
-    // thus corrections for it need to be done in 16-byte chunks at even offsets.
-    // IPv6 nexthdr is at offset 6, while hop limit is at offset 7
-    uint8_t old_hl = ip6->hop_limit;
-    --ip6->hop_limit;
-    uint8_t new_hl = ip6->hop_limit;
-
-    // bpf_csum_update() always succeeds if the skb is CHECKSUM_COMPLETE and returns an error
-    // (-ENOTSUPP) if it isn't.
-    bpf_csum_update(skb, 0xFFFF - ntohs(old_hl) + ntohs(new_hl));
-
-    __sync_fetch_and_add(downstream ? &stat_v->rxPackets : &stat_v->txPackets, packets);
-    __sync_fetch_and_add(downstream ? &stat_v->rxBytes : &stat_v->txBytes, bytes);
-
-    // Overwrite any mac header with the new one
-    // For a rawip tx interface it will simply be a bunch of zeroes and later stripped.
-    *eth = v->macHeader;
-
-    // Redirect to forwarded interface.
-    //
-    // Note that bpf_redirect() cannot fail unless you pass invalid flags.
-    // The redirect actually happens after the ebpf program has already terminated,
-    // and can fail for example for mtu reasons at that point in time, but there's nothing
-    // we can do about it here.
-    return bpf_redirect(v->oif, 0 /* this is effectively BPF_F_EGRESS */);
-}
-
-DEFINE_BPF_PROG("schedcls/tether_downstream6_ether", AID_ROOT, AID_NETWORK_STACK,
-                sched_cls_tether_downstream6_ether)
-(struct __sk_buff* skb) {
-    return do_forward6(skb, /* is_ethernet */ true, /* downstream */ true);
-}
-
-DEFINE_BPF_PROG("schedcls/tether_upstream6_ether", AID_ROOT, AID_NETWORK_STACK,
-                sched_cls_tether_upstream6_ether)
-(struct __sk_buff* skb) {
-    return do_forward6(skb, /* is_ethernet */ true, /* downstream */ false);
-}
-
-// Note: section names must be unique to prevent programs from appending to each other,
-// so instead the bpf loader will strip everything past the final $ symbol when actually
-// pinning the program into the filesystem.
-//
-// bpf_skb_change_head() is only present on 4.14+ and 2 trivial kernel patches are needed:
-//   ANDROID: net: bpf: Allow TC programs to call BPF_FUNC_skb_change_head
-//   ANDROID: net: bpf: permit redirect from ingress L3 to egress L2 devices at near max mtu
-// (the first of those has already been upstreamed)
-//
-// 5.4 kernel support was only added to Android Common Kernel in R,
-// and thus a 5.4 kernel always supports this.
-//
-// Hence, these mandatory (must load successfully) implementations for 5.4+ kernels:
-DEFINE_BPF_PROG_KVER("schedcls/tether_downstream6_rawip$5_4", AID_ROOT, AID_NETWORK_STACK,
-                     sched_cls_tether_downstream6_rawip_5_4, KVER(5, 4, 0))
-(struct __sk_buff* skb) {
-    return do_forward6(skb, /* is_ethernet */ false, /* downstream */ true);
-}
-
-DEFINE_BPF_PROG_KVER("schedcls/tether_upstream6_rawip$5_4", AID_ROOT, AID_NETWORK_STACK,
-                     sched_cls_tether_upstream6_rawip_5_4, KVER(5, 4, 0))
-(struct __sk_buff* skb) {
-    return do_forward6(skb, /* is_ethernet */ false, /* downstream */ false);
-}
-
-// and these identical optional (may fail to load) implementations for [4.14..5.4) patched kernels:
-DEFINE_OPTIONAL_BPF_PROG_KVER_RANGE("schedcls/tether_downstream6_rawip$4_14",
-                                    AID_ROOT, AID_NETWORK_STACK,
-                                    sched_cls_tether_downstream6_rawip_4_14,
-                                    KVER(4, 14, 0), KVER(5, 4, 0))
-(struct __sk_buff* skb) {
-    return do_forward6(skb, /* is_ethernet */ false, /* downstream */ true);
-}
-
-DEFINE_OPTIONAL_BPF_PROG_KVER_RANGE("schedcls/tether_upstream6_rawip$4_14",
-                                    AID_ROOT, AID_NETWORK_STACK,
-                                    sched_cls_tether_upstream6_rawip_4_14,
-                                    KVER(4, 14, 0), KVER(5, 4, 0))
-(struct __sk_buff* skb) {
-    return do_forward6(skb, /* is_ethernet */ false, /* downstream */ false);
-}
-
-// and define no-op stubs for [4.9,4.14) and unpatched [4.14,5.4) kernels.
-// (if the above real 4.14+ program loaded successfully, then bpfloader will have already pinned
-// it at the same location this one would be pinned at and will thus skip loading this stub)
-DEFINE_BPF_PROG_KVER_RANGE("schedcls/tether_downstream6_rawip$stub", AID_ROOT, AID_NETWORK_STACK,
-                           sched_cls_tether_downstream6_rawip_stub, KVER_NONE, KVER(5, 4, 0))
-(struct __sk_buff* skb) {
-    return TC_ACT_PIPE;
-}
-
-DEFINE_BPF_PROG_KVER_RANGE("schedcls/tether_upstream6_rawip$stub", AID_ROOT, AID_NETWORK_STACK,
-                           sched_cls_tether_upstream6_rawip_stub, KVER_NONE, KVER(5, 4, 0))
-(struct __sk_buff* skb) {
-    return TC_ACT_PIPE;
-}
-
-// ----- IPv4 Support -----
-
-DEFINE_BPF_MAP_GRW(tether_downstream4_map, HASH, Tether4Key, Tether4Value, 1024, AID_NETWORK_STACK)
-
-DEFINE_BPF_MAP_GRW(tether_upstream4_map, HASH, Tether4Key, Tether4Value, 1024, AID_NETWORK_STACK)
-
-static inline __always_inline int do_forward4(struct __sk_buff* skb, const bool is_ethernet,
-        const bool downstream, const bool updatetime) {
-    // Require ethernet dst mac address to be our unicast address.
-    if (is_ethernet && (skb->pkt_type != PACKET_HOST)) return TC_ACT_PIPE;
-
-    // Must be meta-ethernet IPv4 frame
-    if (skb->protocol != htons(ETH_P_IP)) return TC_ACT_PIPE;
-
-    const int l2_header_size = is_ethernet ? sizeof(struct ethhdr) : 0;
-
-    // Since the program never writes via DPA (direct packet access) auto-pull/unclone logic does
-    // not trigger and thus we need to manually make sure we can read packet headers via DPA.
-    // Note: this is a blind best effort pull, which may fail or pull less - this doesn't matter.
-    // It has to be done early cause it will invalidate any skb->data/data_end derived pointers.
-    try_make_readable(skb, l2_header_size + IP4_HLEN + TCP_HLEN);
-
-    void* data = (void*)(long)skb->data;
-    const void* data_end = (void*)(long)skb->data_end;
-    struct ethhdr* eth = is_ethernet ? data : NULL;  // used iff is_ethernet
-    struct iphdr* ip = is_ethernet ? (void*)(eth + 1) : data;
-
-    // Must have (ethernet and) ipv4 header
-    if (data + l2_header_size + sizeof(*ip) > data_end) return TC_ACT_PIPE;
-
-    // Ethertype - if present - must be IPv4
-    if (is_ethernet && (eth->h_proto != htons(ETH_P_IP))) return TC_ACT_PIPE;
-
-    // IP version must be 4
-    if (ip->version != 4) TC_PUNT(INVALID_IP_VERSION);
-
-    // We cannot handle IP options, just standard 20 byte == 5 dword minimal IPv4 header
-    if (ip->ihl != 5) TC_PUNT(HAS_IP_OPTIONS);
-
-    // Calculate the IPv4 one's complement checksum of the IPv4 header.
-    __wsum sum4 = 0;
-    for (int i = 0; i < sizeof(*ip) / sizeof(__u16); ++i) {
-        sum4 += ((__u16*)ip)[i];
-    }
-    // Note that sum4 is guaranteed to be non-zero by virtue of ip4->version == 4
-    sum4 = (sum4 & 0xFFFF) + (sum4 >> 16);  // collapse u32 into range 1 .. 0x1FFFE
-    sum4 = (sum4 & 0xFFFF) + (sum4 >> 16);  // collapse any potential carry into u16
-    // for a correct checksum we should get *a* zero, but sum4 must be positive, ie 0xFFFF
-    if (sum4 != 0xFFFF) TC_PUNT(CHECKSUM);
-
-    // Minimum IPv4 total length is the size of the header
-    if (ntohs(ip->tot_len) < sizeof(*ip)) TC_PUNT(TRUNCATED_IPV4);
-
-    // We are incapable of dealing with IPv4 fragments
-    if (ip->frag_off & ~htons(IP_DF)) TC_PUNT(IS_IP_FRAG);
-
-    // Cannot decrement during forward if already zero or would be zero,
-    // Let the kernel's stack handle these cases and generate appropriate ICMP errors.
-    if (ip->ttl <= 1) TC_PUNT(LOW_TTL);
-
-    // If we cannot update the 'last_used' field due to lack of bpf_ktime_get_boot_ns() helper,
-    // then it is not safe to offload UDP due to the small conntrack timeouts, as such,
-    // in such a situation we can only support TCP.  This also has the added nice benefit of
-    // using a separate error counter, and thus making it obvious which version of the program
-    // is loaded.
-    if (!updatetime && ip->protocol != IPPROTO_TCP) TC_PUNT(NON_TCP);
-
-    // We do not support offloading anything besides IPv4 TCP and UDP, due to need for NAT,
-    // but no need to check this if !updatetime due to check immediately above.
-    if (updatetime && (ip->protocol != IPPROTO_TCP) && (ip->protocol != IPPROTO_UDP))
-        TC_PUNT(NON_TCP_UDP);
-
-    // We want to make sure that the compiler will, in the !updatetime case, entirely optimize
-    // out all the non-tcp logic.  Also note that at this point is_udp === !is_tcp.
-    const bool is_tcp = !updatetime || (ip->protocol == IPPROTO_TCP);
-
-    // This is a bit of a hack to make things easier on the bpf verifier.
-    // (In particular I believe the Linux 4.14 kernel's verifier can get confused later on about
-    // what offsets into the packet are valid and can spuriously reject the program, this is
-    // because it fails to realize that is_tcp && !is_tcp is impossible)
-    //
-    // For both TCP & UDP we'll need to read and modify the src/dst ports, which so happen to
-    // always be in the first 4 bytes of the L4 header.  Additionally for UDP we'll need access
-    // to the checksum field which is in bytes 7 and 8.  While for TCP we'll need to read the
-    // TCP flags (at offset 13) and access to the checksum field (2 bytes at offset 16).
-    // As such we *always* need access to at least 8 bytes.
-    if (data + l2_header_size + sizeof(*ip) + 8 > data_end) TC_PUNT(SHORT_L4_HEADER);
-
-    struct tcphdr* tcph = is_tcp ? (void*)(ip + 1) : NULL;
-    struct udphdr* udph = is_tcp ? NULL : (void*)(ip + 1);
-
-    if (is_tcp) {
-        // Make sure we can get at the tcp header
-        if (data + l2_header_size + sizeof(*ip) + sizeof(*tcph) > data_end)
-            TC_PUNT(SHORT_TCP_HEADER);
-
-        // If hardware offload is running and programming flows based on conntrack entries, try not
-        // to interfere with it, so do not offload TCP packets with any one of the SYN/FIN/RST flags
-        if (tcph->syn || tcph->fin || tcph->rst) TC_PUNT(TCP_CONTROL_PACKET);
-    } else { // UDP
-        // Make sure we can get at the udp header
-        if (data + l2_header_size + sizeof(*ip) + sizeof(*udph) > data_end)
-            TC_PUNT(SHORT_UDP_HEADER);
-
-        // Skip handling of CHECKSUM_COMPLETE packets with udp checksum zero due to need for
-        // additional updating of skb->csum (this could be fixed up manually with more effort).
-        //
-        // Note that the in-kernel implementation of 'int64_t bpf_csum_update(skb, u32 csum)' is:
-        //   if (skb->ip_summed == CHECKSUM_COMPLETE)
-        //     return (skb->csum = csum_add(skb->csum, csum));
-        //   else
-        //     return -ENOTSUPP;
-        //
-        // So this will punt any CHECKSUM_COMPLETE packet with a zero UDP checksum,
-        // and leave all other packets unaffected (since it just at most adds zero to skb->csum).
-        //
-        // In practice this should almost never trigger because most nics do not generate
-        // CHECKSUM_COMPLETE packets on receive - especially so for nics/drivers on a phone.
-        //
-        // Additionally since we're forwarding, in most cases the value of the skb->csum field
-        // shouldn't matter (it's not used by physical nic egress).
-        //
-        // It only matters if we're ingressing through a CHECKSUM_COMPLETE capable nic
-        // and egressing through a virtual interface looping back to the kernel itself
-        // (ie. something like veth) where the CHECKSUM_COMPLETE/skb->csum can get reused
-        // on ingress.
-        //
-        // If we were in the kernel we'd simply probably call
-        //   void skb_checksum_complete_unset(struct sk_buff *skb) {
-        //     if (skb->ip_summed == CHECKSUM_COMPLETE) skb->ip_summed = CHECKSUM_NONE;
-        //   }
-        // here instead.  Perhaps there should be a bpf helper for that?
-        if (!udph->check && (bpf_csum_update(skb, 0) >= 0)) TC_PUNT(UDP_CSUM_ZERO);
-    }
-
-    Tether4Key k = {
-            .iif = skb->ifindex,
-            .l4Proto = ip->protocol,
-            .src4.s_addr = ip->saddr,
-            .dst4.s_addr = ip->daddr,
-            .srcPort = is_tcp ? tcph->source : udph->source,
-            .dstPort = is_tcp ? tcph->dest : udph->dest,
-    };
-    if (is_ethernet) __builtin_memcpy(k.dstMac, eth->h_dest, ETH_ALEN);
-
-    Tether4Value* v = downstream ? bpf_tether_downstream4_map_lookup_elem(&k)
-                                 : bpf_tether_upstream4_map_lookup_elem(&k);
-
-    // If we don't find any offload information then simply let the core stack handle it...
-    if (!v) return TC_ACT_PIPE;
-
-    uint32_t stat_and_limit_k = downstream ? skb->ifindex : v->oif;
-
-    TetherStatsValue* stat_v = bpf_tether_stats_map_lookup_elem(&stat_and_limit_k);
-
-    // If we don't have anywhere to put stats, then abort...
-    if (!stat_v) TC_PUNT(NO_STATS_ENTRY);
-
-    uint64_t* limit_v = bpf_tether_limit_map_lookup_elem(&stat_and_limit_k);
-
-    // If we don't have a limit, then abort...
-    if (!limit_v) TC_PUNT(NO_LIMIT_ENTRY);
-
-    // Required IPv4 minimum mtu is 68, below that not clear what we should do, abort...
-    if (v->pmtu < 68) TC_PUNT(BELOW_IPV4_MTU);
-
-    // Approximate handling of TCP/IPv4 overhead for incoming LRO/GRO packets: default
-    // outbound path mtu of 1500 is not necessarily correct, but worst case we simply
-    // undercount, which is still better then not accounting for this overhead at all.
-    // Note: this really shouldn't be device/path mtu at all, but rather should be
-    // derived from this particular connection's mss (ie. from gro segment size).
-    // This would require a much newer kernel with newer ebpf accessors.
-    // (This is also blindly assuming 12 bytes of tcp timestamp option in tcp header)
-    uint64_t packets = 1;
-    uint64_t bytes = skb->len;
-    if (bytes > v->pmtu) {
-        const int tcp_overhead = sizeof(struct iphdr) + sizeof(struct tcphdr) + 12;
-        const int mss = v->pmtu - tcp_overhead;
-        const uint64_t payload = bytes - tcp_overhead;
-        packets = (payload + mss - 1) / mss;
-        bytes = tcp_overhead * packets + payload;
-    }
-
-    // Are we past the limit?  If so, then abort...
-    // Note: will not overflow since u64 is 936 years even at 5Gbps.
-    // Do not drop here.  Offload is just that, whenever we fail to handle
-    // a packet we let the core stack deal with things.
-    // (The core stack needs to handle limits correctly anyway,
-    // since we don't offload all traffic in both directions)
-    if (stat_v->rxBytes + stat_v->txBytes + bytes > *limit_v) TC_PUNT(LIMIT_REACHED);
-
-    if (!is_ethernet) {
-        // Try to inject an ethernet header, and simply return if we fail.
-        // We do this even if TX interface is RAWIP and thus does not need an ethernet header,
-        // because this is easier and the kernel will strip extraneous ethernet header.
-        if (bpf_skb_change_head(skb, sizeof(struct ethhdr), /*flags*/ 0)) {
-            __sync_fetch_and_add(downstream ? &stat_v->rxErrors : &stat_v->txErrors, 1);
-            TC_PUNT(CHANGE_HEAD_FAILED);
-        }
-
-        // bpf_skb_change_head() invalidates all pointers - reload them
-        data = (void*)(long)skb->data;
-        data_end = (void*)(long)skb->data_end;
-        eth = data;
-        ip = (void*)(eth + 1);
-        tcph = is_tcp ? (void*)(ip + 1) : NULL;
-        udph = is_tcp ? NULL : (void*)(ip + 1);
-
-        // I do not believe this can ever happen, but keep the verifier happy...
-        if (data + sizeof(struct ethhdr) + sizeof(*ip) + (is_tcp ? sizeof(*tcph) : sizeof(*udph)) > data_end) {
-            __sync_fetch_and_add(downstream ? &stat_v->rxErrors : &stat_v->txErrors, 1);
-            TC_DROP(TOO_SHORT);
-        }
-    };
-
-    // At this point we always have an ethernet header - which will get stripped by the
-    // kernel during transmit through a rawip interface.  ie. 'eth' pointer is valid.
-    // Additionally note that 'is_ethernet' and 'l2_header_size' are no longer correct.
-
-    // Overwrite any mac header with the new one
-    // For a rawip tx interface it will simply be a bunch of zeroes and later stripped.
-    *eth = v->macHeader;
-
-    // Decrement the IPv4 TTL, we already know it's greater than 1.
-    // u8 TTL field is followed by u8 protocol to make a u16 for ipv4 header checksum update.
-    // Since we're keeping the ipv4 checksum valid (which means the checksum of the entire
-    // ipv4 header remains 0), the overall checksum of the entire packet does not change.
-    const int sz2 = sizeof(__be16);
-    const __be16 old_ttl_proto = *(__be16 *)&ip->ttl;
-    const __be16 new_ttl_proto = old_ttl_proto - htons(0x0100);
-    bpf_l3_csum_replace(skb, ETH_IP4_OFFSET(check), old_ttl_proto, new_ttl_proto, sz2);
-    bpf_skb_store_bytes(skb, ETH_IP4_OFFSET(ttl), &new_ttl_proto, sz2, 0);
-
-    const int l4_offs_csum = is_tcp ? ETH_IP4_TCP_OFFSET(check) : ETH_IP4_UDP_OFFSET(check);
-    const int sz4 = sizeof(__be32);
-    // UDP 0 is special and stored as FFFF (this flag also causes a csum of 0 to be unmodified)
-    const int l4_flags = is_tcp ? 0 : BPF_F_MARK_MANGLED_0;
-    const __be32 old_daddr = k.dst4.s_addr;
-    const __be32 old_saddr = k.src4.s_addr;
-    const __be32 new_daddr = v->dst46.s6_addr32[3];
-    const __be32 new_saddr = v->src46.s6_addr32[3];
-
-    bpf_l4_csum_replace(skb, l4_offs_csum, old_daddr, new_daddr, sz4 | BPF_F_PSEUDO_HDR | l4_flags);
-    bpf_l3_csum_replace(skb, ETH_IP4_OFFSET(check), old_daddr, new_daddr, sz4);
-    bpf_skb_store_bytes(skb, ETH_IP4_OFFSET(daddr), &new_daddr, sz4, 0);
-
-    bpf_l4_csum_replace(skb, l4_offs_csum, old_saddr, new_saddr, sz4 | BPF_F_PSEUDO_HDR | l4_flags);
-    bpf_l3_csum_replace(skb, ETH_IP4_OFFSET(check), old_saddr, new_saddr, sz4);
-    bpf_skb_store_bytes(skb, ETH_IP4_OFFSET(saddr), &new_saddr, sz4, 0);
-
-    // The offsets for TCP and UDP ports: source (u16 @ L4 offset 0) & dest (u16 @ L4 offset 2) are
-    // actually the same, so the compiler should just optimize them both down to a constant.
-    bpf_l4_csum_replace(skb, l4_offs_csum, k.srcPort, v->srcPort, sz2 | l4_flags);
-    bpf_skb_store_bytes(skb, is_tcp ? ETH_IP4_TCP_OFFSET(source) : ETH_IP4_UDP_OFFSET(source),
-                        &v->srcPort, sz2, 0);
-
-    bpf_l4_csum_replace(skb, l4_offs_csum, k.dstPort, v->dstPort, sz2 | l4_flags);
-    bpf_skb_store_bytes(skb, is_tcp ? ETH_IP4_TCP_OFFSET(dest) : ETH_IP4_UDP_OFFSET(dest),
-                        &v->dstPort, sz2, 0);
-
-    // This requires the bpf_ktime_get_boot_ns() helper which was added in 5.8,
-    // and backported to all Android Common Kernel 4.14+ trees.
-    if (updatetime) v->last_used = bpf_ktime_get_boot_ns();
-
-    __sync_fetch_and_add(downstream ? &stat_v->rxPackets : &stat_v->txPackets, packets);
-    __sync_fetch_and_add(downstream ? &stat_v->rxBytes : &stat_v->txBytes, bytes);
-
-    // Redirect to forwarded interface.
-    //
-    // Note that bpf_redirect() cannot fail unless you pass invalid flags.
-    // The redirect actually happens after the ebpf program has already terminated,
-    // and can fail for example for mtu reasons at that point in time, but there's nothing
-    // we can do about it here.
-    return bpf_redirect(v->oif, 0 /* this is effectively BPF_F_EGRESS */);
-}
-
-// Full featured (required) implementations for 5.8+ kernels (these are S+ by definition)
-
-DEFINE_BPF_PROG_KVER("schedcls/tether_downstream4_rawip$5_8", AID_ROOT, AID_NETWORK_STACK,
-                     sched_cls_tether_downstream4_rawip_5_8, KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ false, /* downstream */ true, /* updatetime */ true);
-}
-
-DEFINE_BPF_PROG_KVER("schedcls/tether_upstream4_rawip$5_8", AID_ROOT, AID_NETWORK_STACK,
-                     sched_cls_tether_upstream4_rawip_5_8, KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ false, /* downstream */ false, /* updatetime */ true);
-}
-
-DEFINE_BPF_PROG_KVER("schedcls/tether_downstream4_ether$5_8", AID_ROOT, AID_NETWORK_STACK,
-                     sched_cls_tether_downstream4_ether_5_8, KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ true, /* downstream */ true, /* updatetime */ true);
-}
-
-DEFINE_BPF_PROG_KVER("schedcls/tether_upstream4_ether$5_8", AID_ROOT, AID_NETWORK_STACK,
-                     sched_cls_tether_upstream4_ether_5_8, KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ true, /* downstream */ false, /* updatetime */ true);
-}
-
-// Full featured (optional) implementations for 4.14-S, 4.19-S & 5.4-S kernels
-// (optional, because we need to be able to fallback for 4.14/4.19/5.4 pre-S kernels)
-
-DEFINE_OPTIONAL_BPF_PROG_KVER_RANGE("schedcls/tether_downstream4_rawip$opt",
-                                    AID_ROOT, AID_NETWORK_STACK,
-                                    sched_cls_tether_downstream4_rawip_opt,
-                                    KVER(4, 14, 0), KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ false, /* downstream */ true, /* updatetime */ true);
-}
-
-DEFINE_OPTIONAL_BPF_PROG_KVER_RANGE("schedcls/tether_upstream4_rawip$opt",
-                                    AID_ROOT, AID_NETWORK_STACK,
-                                    sched_cls_tether_upstream4_rawip_opt,
-                                    KVER(4, 14, 0), KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ false, /* downstream */ false, /* updatetime */ true);
-}
-
-DEFINE_OPTIONAL_BPF_PROG_KVER_RANGE("schedcls/tether_downstream4_ether$opt",
-                                    AID_ROOT, AID_NETWORK_STACK,
-                                    sched_cls_tether_downstream4_ether_opt,
-                                    KVER(4, 14, 0), KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ true, /* downstream */ true, /* updatetime */ true);
-}
-
-DEFINE_OPTIONAL_BPF_PROG_KVER_RANGE("schedcls/tether_upstream4_ether$opt",
-                                    AID_ROOT, AID_NETWORK_STACK,
-                                    sched_cls_tether_upstream4_ether_opt,
-                                    KVER(4, 14, 0), KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ true, /* downstream */ false, /* updatetime */ true);
-}
-
-// Partial (TCP-only: will not update 'last_used' field) implementations for 4.14+ kernels.
-// These will be loaded only if the above optional ones failed (loading of *these* must succeed
-// for 5.4+, since that is always an R patched kernel).
-//
-// [Note: as a result TCP connections will not have their conntrack timeout refreshed, however,
-// since /proc/sys/net/netfilter/nf_conntrack_tcp_timeout_established defaults to 432000 (seconds),
-// this in practice means they'll break only after 5 days.  This seems an acceptable trade-off.
-//
-// Additionally kernel/tests change "net-test: add bpf_ktime_get_ns / bpf_ktime_get_boot_ns tests"
-// which enforces and documents the required kernel cherrypicks will make it pretty unlikely that
-// many devices upgrading to S will end up relying on these fallback programs.
-
-// RAWIP: Required for 5.4-R kernels -- which always support bpf_skb_change_head().
-
-DEFINE_BPF_PROG_KVER_RANGE("schedcls/tether_downstream4_rawip$5_4", AID_ROOT, AID_NETWORK_STACK,
-                           sched_cls_tether_downstream4_rawip_5_4, KVER(5, 4, 0), KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ false, /* downstream */ true, /* updatetime */ false);
-}
-
-DEFINE_BPF_PROG_KVER_RANGE("schedcls/tether_upstream4_rawip$5_4", AID_ROOT, AID_NETWORK_STACK,
-                           sched_cls_tether_upstream4_rawip_5_4, KVER(5, 4, 0), KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ false, /* downstream */ false, /* updatetime */ false);
-}
-
-// RAWIP: Optional for 4.14/4.19 (R) kernels -- which support bpf_skb_change_head().
-// [Note: fallback for 4.14/4.19 (P/Q) kernels is below in stub section]
-
-DEFINE_OPTIONAL_BPF_PROG_KVER_RANGE("schedcls/tether_downstream4_rawip$4_14",
-                                    AID_ROOT, AID_NETWORK_STACK,
-                                    sched_cls_tether_downstream4_rawip_4_14,
-                                    KVER(4, 14, 0), KVER(5, 4, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ false, /* downstream */ true, /* updatetime */ false);
-}
-
-DEFINE_OPTIONAL_BPF_PROG_KVER_RANGE("schedcls/tether_upstream4_rawip$4_14",
-                                    AID_ROOT, AID_NETWORK_STACK,
-                                    sched_cls_tether_upstream4_rawip_4_14,
-                                    KVER(4, 14, 0), KVER(5, 4, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ false, /* downstream */ false, /* updatetime */ false);
-}
-
-// ETHER: Required for 4.14-Q/R, 4.19-Q/R & 5.4-R kernels.
-
-DEFINE_BPF_PROG_KVER_RANGE("schedcls/tether_downstream4_ether$4_14", AID_ROOT, AID_NETWORK_STACK,
-                           sched_cls_tether_downstream4_ether_4_14, KVER(4, 14, 0), KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ true, /* downstream */ true, /* updatetime */ false);
-}
-
-DEFINE_BPF_PROG_KVER_RANGE("schedcls/tether_upstream4_ether$4_14", AID_ROOT, AID_NETWORK_STACK,
-                           sched_cls_tether_upstream4_ether_4_14, KVER(4, 14, 0), KVER(5, 8, 0))
-(struct __sk_buff* skb) {
-    return do_forward4(skb, /* is_ethernet */ true, /* downstream */ false, /* updatetime */ false);
-}
-
-// Placeholder (no-op) implementations for older Q kernels
-
-// RAWIP: 4.9-P/Q, 4.14-P/Q & 4.19-Q kernels -- without bpf_skb_change_head() for tc programs
-
-DEFINE_BPF_PROG_KVER_RANGE("schedcls/tether_downstream4_rawip$stub", AID_ROOT, AID_NETWORK_STACK,
-                           sched_cls_tether_downstream4_rawip_stub, KVER_NONE, KVER(5, 4, 0))
-(struct __sk_buff* skb) {
-    return TC_ACT_PIPE;
-}
-
-DEFINE_BPF_PROG_KVER_RANGE("schedcls/tether_upstream4_rawip$stub", AID_ROOT, AID_NETWORK_STACK,
-                           sched_cls_tether_upstream4_rawip_stub, KVER_NONE, KVER(5, 4, 0))
-(struct __sk_buff* skb) {
-    return TC_ACT_PIPE;
-}
-
-// ETHER: 4.9-P/Q kernel
-
-DEFINE_BPF_PROG_KVER_RANGE("schedcls/tether_downstream4_ether$stub", AID_ROOT, AID_NETWORK_STACK,
-                           sched_cls_tether_downstream4_ether_stub, KVER_NONE, KVER(4, 14, 0))
-(struct __sk_buff* skb) {
-    return TC_ACT_PIPE;
-}
-
-DEFINE_BPF_PROG_KVER_RANGE("schedcls/tether_upstream4_ether$stub", AID_ROOT, AID_NETWORK_STACK,
-                           sched_cls_tether_upstream4_ether_stub, KVER_NONE, KVER(4, 14, 0))
-(struct __sk_buff* skb) {
-    return TC_ACT_PIPE;
-}
-
-// ----- XDP Support -----
-
-DEFINE_BPF_MAP_GRW(tether_dev_map, DEVMAP_HASH, uint32_t, uint32_t, 64, AID_NETWORK_STACK)
-
-static inline __always_inline int do_xdp_forward6(struct xdp_md *ctx, const bool is_ethernet,
-        const bool downstream) {
-    return XDP_PASS;
-}
-
-static inline __always_inline int do_xdp_forward4(struct xdp_md *ctx, const bool is_ethernet,
-        const bool downstream) {
-    return XDP_PASS;
-}
-
-static inline __always_inline int do_xdp_forward_ether(struct xdp_md *ctx, const bool downstream) {
-    const void* data = (void*)(long)ctx->data;
-    const void* data_end = (void*)(long)ctx->data_end;
-    const struct ethhdr* eth = data;
-
-    // Make sure we actually have an ethernet header
-    if ((void*)(eth + 1) > data_end) return XDP_PASS;
-
-    if (eth->h_proto == htons(ETH_P_IPV6))
-        return do_xdp_forward6(ctx, /* is_ethernet */ true, downstream);
-    if (eth->h_proto == htons(ETH_P_IP))
-        return do_xdp_forward4(ctx, /* is_ethernet */ true, downstream);
-
-    // Anything else we don't know how to handle...
-    return XDP_PASS;
-}
-
-static inline __always_inline int do_xdp_forward_rawip(struct xdp_md *ctx, const bool downstream) {
-    const void* data = (void*)(long)ctx->data;
-    const void* data_end = (void*)(long)ctx->data_end;
-
-    // The top nibble of both IPv4 and IPv6 headers is the IP version.
-    if (data_end - data < 1) return XDP_PASS;
-    const uint8_t v = (*(uint8_t*)data) >> 4;
-
-    if (v == 6) return do_xdp_forward6(ctx, /* is_ethernet */ false, downstream);
-    if (v == 4) return do_xdp_forward4(ctx, /* is_ethernet */ false, downstream);
-
-    // Anything else we don't know how to handle...
-    return XDP_PASS;
-}
-
-#define DEFINE_XDP_PROG(str, func) \
-    DEFINE_BPF_PROG_KVER(str, AID_ROOT, AID_NETWORK_STACK, func, KVER(5, 9, 0))(struct xdp_md *ctx)
-
-DEFINE_XDP_PROG("xdp/tether_downstream_ether",
-                 xdp_tether_downstream_ether) {
-    return do_xdp_forward_ether(ctx, /* downstream */ true);
-}
-
-DEFINE_XDP_PROG("xdp/tether_downstream_rawip",
-                 xdp_tether_downstream_rawip) {
-    return do_xdp_forward_rawip(ctx, /* downstream */ true);
-}
-
-DEFINE_XDP_PROG("xdp/tether_upstream_ether",
-                 xdp_tether_upstream_ether) {
-    return do_xdp_forward_ether(ctx, /* downstream */ false);
-}
-
-DEFINE_XDP_PROG("xdp/tether_upstream_rawip",
-                 xdp_tether_upstream_rawip) {
-    return do_xdp_forward_rawip(ctx, /* downstream */ false);
-}
-
-LICENSE("Apache 2.0");
-CRITICAL("tethering");
diff --git a/Tethering/bpf_progs/test.c b/Tethering/bpf_progs/test.c
deleted file mode 100644
index a76e346..0000000
--- a/Tethering/bpf_progs/test.c
+++ /dev/null
@@ -1,50 +0,0 @@
-/*
- * Copyright (C) 2021 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.
- */
-
-#include <linux/if_ether.h>
-#include <linux/in.h>
-#include <linux/ip.h>
-
-// The resulting .o needs to load on the Android S bpfloader v0.2
-#define BPFLOADER_MIN_VER 2u
-
-#include "bpf_helpers.h"
-#include "bpf_net_helpers.h"
-#include "bpf_tethering.h"
-
-// Used only by TetheringPrivilegedTests, not by production code.
-DEFINE_BPF_MAP_GRW(tether_downstream6_map, HASH, TetherDownstream6Key, Tether6Value, 16,
-                   AID_NETWORK_STACK)
-
-DEFINE_BPF_PROG_KVER("xdp/drop_ipv4_udp_ether", AID_ROOT, AID_NETWORK_STACK,
-                      xdp_test, KVER(5, 9, 0))
-(struct xdp_md *ctx) {
-    void *data = (void *)(long)ctx->data;
-    void *data_end = (void *)(long)ctx->data_end;
-
-    struct ethhdr *eth = data;
-    int hsize = sizeof(*eth);
-
-    struct iphdr *ip = data + hsize;
-    hsize += sizeof(struct iphdr);
-
-    if (data + hsize > data_end) return XDP_PASS;
-    if (eth->h_proto != htons(ETH_P_IP)) return XDP_PASS;
-    if (ip->protocol == IPPROTO_UDP) return XDP_DROP;
-    return XDP_PASS;
-}
-
-LICENSE("Apache 2.0");
diff --git a/Tethering/tests/privileged/src/com/android/networkstack/tethering/BpfMapTest.java b/Tethering/tests/privileged/src/com/android/networkstack/tethering/BpfMapTest.java
index 646c75f..ad2faa0 100644
--- a/Tethering/tests/privileged/src/com/android/networkstack/tethering/BpfMapTest.java
+++ b/Tethering/tests/privileged/src/com/android/networkstack/tethering/BpfMapTest.java
@@ -50,7 +50,7 @@
 @RunWith(DevSdkIgnoreRunner.class)
 @IgnoreUpTo(Build.VERSION_CODES.R)
 public final class BpfMapTest {
-    // Sync from packages/modules/Connectivity/Tethering/bpf_progs/offload.c.
+    // Sync from packages/modules/Connectivity/bpf_progs/offload.c.
     private static final int TEST_MAP_SIZE = 16;
     private static final String TETHER_DOWNSTREAM6_FS_PATH =
             "/sys/fs/bpf/tethering/map_test_tether_downstream6_map";