LineageOS/android_packages_modules_Connectivity
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bpf offload - make sure bpf code can access packet headers am: 8e69ec111f am: 3129be7a3b am: 4cfddb344c

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Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1622559

Change-Id: I29df9c0df46fd67203e50d30c3ae70eaa43cfeab
This commit is contained in:
Maciej Żenczykowski
2021-04-07 02:46:50 +00:00
committed by Automerger Merge Worker
parent f3066426bf 4cfddb344c
commit 4a3d91fdcb
1 changed files with 27 additions and 13 deletions
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40
Tethering/bpf_progs/offload.c
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@@ -107,17 +107,24 @@ DEFINE_BPF_MAP_GRW(tether_upstream6_map, HASH, TetherUpstream6Key, Tether6Value,
static inline __always_inline int do_forward6(struct __sk_buff* skb, const bool is_ethernet,
const bool downstream) {
const int l2_header_size = is_ethernet ? sizeof(struct ethhdr) : 0;
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 be meta-ethernet IPv6 frame
if (skb->protocol != htons(ETH_P_IPV6)) return TC_ACT_OK;
// Require ethernet dst mac address to be our unicast address.
if (is_ethernet && (skb->pkt_type != PACKET_HOST)) return TC_ACT_OK;
// Must be meta-ethernet IPv6 frame
if (skb->protocol != htons(ETH_P_IPV6)) return TC_ACT_OK;
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_OK;
@@ -346,18 +353,25 @@ DEFINE_BPF_MAP_GRW(tether_upstream4_map, HASH, Tether4Key, Tether4Value, 1024, A
static inline __always_inline int do_forward4(struct __sk_buff* skb, const bool is_ethernet,
const bool downstream, const bool updatetime) {
const int l2_header_size = is_ethernet ? sizeof(struct ethhdr) : 0;
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;
// Require ethernet dst mac address to be our unicast address.
if (is_ethernet && (skb->pkt_type != PACKET_HOST)) return TC_ACT_OK;
// Must be meta-ethernet IPv4 frame
if (skb->protocol != htons(ETH_P_IP)) return TC_ACT_OK;
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_OK;