commit 8549af9f1767a08d917c0d639a3174f9bf0a88db
author Maciej Żenczykowski <maze@google.com> Thu Feb 25 19:11:34 2021 -0800
committer Maciej Żenczykowski <maze@google.com> Thu Feb 25 19:11:39 2021 -0800
tree 7465228494ec9a2b200cf4dc9db05ec6d18b77ed
parent 607d6dda0d709adb269e02d0947895f121518474

ebpf offload: bump size of ipv4 tethering maps

For ipv6 we need 1 entry per client, so 64 seems like plenty,
while for ipv4 we need 1 entry per flow, so even 1024 seems
like it might not be enough, but it's much better than 64.

Nucca says:
  # cat proc/sys/net/netfilter/nf_conntrack_buckets
  65536
  # cat proc/sys/net/netfilter/nf_conntrack_max
  262144

  per https://www.kernel.org/doc/Documentation/networking/nf_conntrack-sysctl.txt
  the default “nf_conntrack_max” is “nf_conntrack_buckets * 4”.

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ib7d1d8c19bc688c442d842cf5c9f45cdf1241754

Tethering/bpf_progs/offload.c

diff --git a/Tethering/bpf_progs/offload.c b/Tethering/bpf_progs/offload.c
index a5aae90..432fc32 100644
--- a/Tethering/bpf_progs/offload.c
+++ b/Tethering/bpf_progs/offload.c
@@ -101,7 +101,7 @@
                    AID_NETWORK_STACK)
 
 DEFINE_BPF_MAP_GRW(tether_downstream64_map, HASH, TetherDownstream64Key, TetherDownstream64Value,
-                   64, AID_NETWORK_STACK)
+                   1024, AID_NETWORK_STACK)
 
 DEFINE_BPF_MAP_GRW(tether_upstream6_map, HASH, TetherUpstream6Key, Tether6Value, 64,
                    AID_NETWORK_STACK)
@@ -341,9 +341,9 @@
 
 // ----- IPv4 Support -----
 
-DEFINE_BPF_MAP_GRW(tether_downstream4_map, HASH, Tether4Key, Tether4Value, 64, AID_NETWORK_STACK)
+DEFINE_BPF_MAP_GRW(tether_downstream4_map, HASH, Tether4Key, Tether4Value, 1024, AID_NETWORK_STACK)
 
-DEFINE_BPF_MAP_GRW(tether_upstream4_map, HASH, Tether4Key, Tether4Value, 64, 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) {