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authorMartin KaFai Lau <kafai@fb.com>2020-08-20 12:00:14 -0700
committerAlexei Starovoitov <ast@kernel.org>2020-08-24 14:34:59 -0700
commit70a217f1976f75a6cfe8223e5669ad7b405daaad (patch)
tree56f92c968ad9e132de0c19761b648cdc3d38c518 /include/linux/tcp.h
parent9c0f8cbdc0e9cf8a2a3a96045778b8d759f172c2 (diff)
tcp: Use a struct to represent a saved_syn
The TCP_SAVE_SYN has both the network header and tcp header. The total length of the saved syn packet is currently stored in the first 4 bytes (u32) of an array and the actual packet data is stored after that. A later patch will add a bpf helper that allows to get the tcp header alone from the saved syn without the network header. It will be more convenient to have a direct offset to a specific header instead of re-parsing it. This requires to separately store the network hdrlen. The total header length (i.e. network + tcp) is still needed for the current usage in getsockopt. Although this total length can be obtained by looking into the tcphdr and then get the (th->doff << 2), this patch chooses to directly store the tcp hdrlen in the second four bytes of this newly created "struct saved_syn". By using a new struct, it can give a readable name to each individual header length. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200820190014.2883694-1-kafai@fb.com
Diffstat (limited to 'include/linux/tcp.h')
-rw-r--r--include/linux/tcp.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 14b62d7df942..2088d5a079af 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -406,7 +406,7 @@ struct tcp_sock {
* socket. Used to retransmit SYNACKs etc.
*/
struct request_sock __rcu *fastopen_rsk;
- u32 *saved_syn;
+ struct saved_syn *saved_syn;
};
enum tsq_enum {
@@ -484,6 +484,11 @@ static inline void tcp_saved_syn_free(struct tcp_sock *tp)
tp->saved_syn = NULL;
}
+static inline u32 tcp_saved_syn_len(const struct saved_syn *saved_syn)
+{
+ return saved_syn->network_hdrlen + saved_syn->tcp_hdrlen;
+}
+
struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk,
const struct sk_buff *orig_skb);