From ff27fd63cdd95490e2f9f4e67dbf70324ed6ed9b Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 17 Nov 2022 16:58:44 +1100 Subject: tcp: Add connection union type Currently, the tables for spliced and non-spliced connections are entirely separate, with different types in different arrays. We want to unify them. As a first step, create a union type which can represent either a spliced or non-spliced connection. For them to be distinguishable, the individual types need to have a common header added, with a bit indicating which type this structure is. This comes at the cost of increasing the size of tcp_tap_conn to over one (64 byte) cacheline. This isn't ideal, but it makes things simpler for now and we'll re-optimize this later. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- tcp_conn.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'tcp_conn.h') diff --git a/tcp_conn.h b/tcp_conn.h index db4c2d9..39d104a 100644 --- a/tcp_conn.h +++ b/tcp_conn.h @@ -11,8 +11,19 @@ #define TCP_HASH_BUCKET_BITS (TCP_CONN_INDEX_BITS + 1) +/** + * struct tcp_conn_common - Common fields for spliced and non-spliced + * @spliced: Is this a spliced connection? + */ +struct tcp_conn_common { + bool spliced :1; +}; + +extern const char *tcp_common_flag_str[]; + /** * struct tcp_tap_conn - Descriptor for a TCP connection (not spliced) + * @c: Fields common with tcp_splice_conn * @next_index: Connection index of next item in hash chain, -1 for none * @tap_mss: MSS advertised by tap/guest, rounded to 2 ^ TCP_MSS_BITS * @sock: Socket descriptor number @@ -40,6 +51,9 @@ * @seq_init_from_tap: Initial sequence number from tap */ struct tcp_tap_conn { + /* Must be first element to match tcp_splice_conn */ + struct tcp_conn_common c; + int next_index :TCP_CONN_INDEX_BITS + 2; #define TCP_RETRANS_BITS 3 @@ -122,6 +136,7 @@ struct tcp_tap_conn { /** * struct tcp_splice_conn - Descriptor for a spliced TCP connection + * @c: Fields common with tcp_tap_conn * @a: File descriptor number of socket for accepted connection * @pipe_a_b: Pipe ends for splice() from @a to @b * @b: File descriptor number of peer connected socket @@ -134,6 +149,9 @@ struct tcp_tap_conn { * @b_written: Bytes written to @b (not fully written from one @a read) */ struct tcp_splice_conn { + /* Must be first element to match tcp_tap_conn */ + struct tcp_conn_common c; + int a; int pipe_a_b[2]; int b; @@ -165,4 +183,16 @@ struct tcp_splice_conn { uint32_t b_written; }; +/** + * union tcp_conn - Descriptor for a TCP connection (spliced or non-spliced) + * @c: Fields common between all variants + * @tap: Fields specific to non-spliced connections + * @splice: Fields specific to spliced connections +*/ +union tcp_conn { + struct tcp_conn_common c; + struct tcp_tap_conn tap; + struct tcp_splice_conn splice; +}; + #endif /* TCP_CONN_H */ -- cgit v1.2.3