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| author | Maciej Żenczykowski <maze@google.com> | 2020-07-22 21:37:51 +0000 |
|---|---|---|
| committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | 2020-07-22 21:37:51 +0000 |
| commit | b614508cbb1a7b96d4a37dbd77141aa313a6256d (patch) | |
| tree | 00bf302e6b69c9c3b22f2e444bf0c510688dd38d | |
| parent | 8ff30f55426be8a89ffef622bba56e542e5a9d66 (diff) | |
| parent | 59b62e64ce48e585f038780d569001c714b0910f (diff) | |
| download | netd-b614508cbb1a7b96d4a37dbd77141aa313a6256d.tar.gz | |
bpf_progs/clatd - do not tx offload ipv4/udp packets with 0 checksum am: 59b62e64ce
Original change: https://googleplex-android-review.googlesource.com/c/platform/system/netd/+/12161669
Change-Id: I4ce41d754c0ad741625efa931395aded64a62154
| -rw-r--r-- | bpf_progs/clatd.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/bpf_progs/clatd.c b/bpf_progs/clatd.c index 102ecd96..e7586928 100644 --- a/bpf_progs/clatd.c +++ b/bpf_progs/clatd.c @@ -26,6 +26,10 @@ #include <stdbool.h> #include <stdint.h> +// bionic kernel uapi linux/udp.h header is munged... +#define __kernel_udphdr udphdr +#include <linux/udp.h> + #include "bpf_helpers.h" #include "bpf_net_helpers.h" #include "netdbpf/bpf_shared.h" @@ -226,9 +230,18 @@ int sched_cls_egress_clat_rawip(struct __sk_buff* skb) { switch (ip4->protocol) { case IPPROTO_TCP: // For TCP & UDP the checksum neutrality of the chosen IPv6 - case IPPROTO_UDP: // address means there is no need to update their checksums. - case IPPROTO_GRE: // We do not need to bother looking at GRE/ESP headers, - case IPPROTO_ESP: // since there is never a checksum to update. + case IPPROTO_GRE: // address means there is no need to update their checksums. + case IPPROTO_ESP: // We do not need to bother looking at GRE/ESP headers, + break; // since there is never a checksum to update. + + case IPPROTO_UDP: // See above comment, but must also have UDP header... + if (data + sizeof(*ip4) + sizeof(struct udphdr) > data_end) return TC_ACT_OK; + const struct udphdr* uh = (const struct udphdr*)(ip4 + 1); + // If IPv4/UDP checksum is 0 then fallback to clatd so it can calculate the + // checksum. Otherwise the network or more likely the NAT64 gateway might + // drop the packet because in most cases IPv6/UDP packets with a zero checksum + // are invalid. See RFC 6935. TODO: calculate checksum via bpf_csum_diff() + if (!uh->check) return TC_ACT_OK; break; default: // do not know how to handle anything else |