diff options
Diffstat (limited to 'tcp_conn.h')
| -rw-r--r-- | tcp_conn.h | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/tcp_conn.h b/tcp_conn.h new file mode 100644 index 0000000..db4c2d9 --- /dev/null +++ b/tcp_conn.h @@ -0,0 +1,168 @@ +/* SPDX-License-Identifier: AGPL-3.0-or-later + * Copyright Red Hat + * Author: Stefano Brivio <sbrivio@redhat.com> + * Author: David Gibson <david@gibson.dropbear.id.au> + * + * TCP connection tracking data structures, used by tcp.c and + * tcp_splice.c. Shouldn't be included in non-TCP code. + */ +#ifndef TCP_CONN_H +#define TCP_CONN_H + +#define TCP_HASH_BUCKET_BITS (TCP_CONN_INDEX_BITS + 1) + +/** + * struct tcp_tap_conn - Descriptor for a TCP connection (not spliced) + * @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 + * @events: Connection events, implying connection states + * @timer: timerfd descriptor for timeout events + * @flags: Connection flags representing internal attributes + * @hash_bucket: Bucket index in connection lookup hash table + * @retrans: Number of retransmissions occurred due to ACK_TIMEOUT + * @ws_from_tap: Window scaling factor advertised from tap/guest + * @ws_to_tap: Window scaling factor advertised to tap/guest + * @sndbuf: Sending buffer in kernel, rounded to 2 ^ SNDBUF_BITS + * @seq_dup_ack_approx: Last duplicate ACK number sent to tap + * @a.a6: IPv6 remote address, can be IPv4-mapped + * @a.a4.zero: Zero prefix for IPv4-mapped, see RFC 6890, Table 20 + * @a.a4.one: Ones prefix for IPv4-mapped + * @a.a4.a: IPv4 address + * @tap_port: Guest-facing tap port + * @sock_port: Remote, socket-facing port + * @wnd_from_tap: Last window size from tap, unscaled (as received) + * @wnd_to_tap: Sending window advertised to tap, unscaled (as sent) + * @seq_to_tap: Next sequence for packets to tap + * @seq_ack_from_tap: Last ACK number received from tap + * @seq_from_tap: Next sequence for packets from tap (not actually sent) + * @seq_ack_to_tap: Last ACK number sent to tap + * @seq_init_from_tap: Initial sequence number from tap + */ +struct tcp_tap_conn { + int next_index :TCP_CONN_INDEX_BITS + 2; + +#define TCP_RETRANS_BITS 3 + unsigned int retrans :TCP_RETRANS_BITS; +#define TCP_MAX_RETRANS ((1U << TCP_RETRANS_BITS) - 1) + +#define TCP_WS_BITS 4 /* RFC 7323 */ +#define TCP_WS_MAX 14 + unsigned int ws_from_tap :TCP_WS_BITS; + unsigned int ws_to_tap :TCP_WS_BITS; + + + int sock :SOCKET_REF_BITS; + + uint8_t events; +#define CLOSED 0 +#define SOCK_ACCEPTED BIT(0) /* implies SYN sent to tap */ +#define TAP_SYN_RCVD BIT(1) /* implies socket connecting */ +#define TAP_SYN_ACK_SENT BIT( 3) /* implies socket connected */ +#define ESTABLISHED BIT(2) +#define SOCK_FIN_RCVD BIT( 3) +#define SOCK_FIN_SENT BIT( 4) +#define TAP_FIN_RCVD BIT( 5) +#define TAP_FIN_SENT BIT( 6) +#define TAP_FIN_ACKED BIT( 7) + +#define CONN_STATE_BITS /* Setting these clears other flags */ \ + (SOCK_ACCEPTED | TAP_SYN_RCVD | ESTABLISHED) + + + int timer :SOCKET_REF_BITS; + + uint8_t flags; +#define STALLED BIT(0) +#define LOCAL BIT(1) +#define WND_CLAMPED BIT(2) +#define IN_EPOLL BIT(3) +#define ACTIVE_CLOSE BIT(4) +#define ACK_TO_TAP_DUE BIT(5) +#define ACK_FROM_TAP_DUE BIT(6) + + + unsigned int hash_bucket :TCP_HASH_BUCKET_BITS; + +#define TCP_MSS_BITS 14 + unsigned int tap_mss :TCP_MSS_BITS; +#define MSS_SET(conn, mss) (conn->tap_mss = (mss >> (16 - TCP_MSS_BITS))) +#define MSS_GET(conn) (conn->tap_mss << (16 - TCP_MSS_BITS)) + + +#define SNDBUF_BITS 24 + unsigned int sndbuf :SNDBUF_BITS; +#define SNDBUF_SET(conn, bytes) (conn->sndbuf = ((bytes) >> (32 - SNDBUF_BITS))) +#define SNDBUF_GET(conn) (conn->sndbuf << (32 - SNDBUF_BITS)) + + uint8_t seq_dup_ack_approx; + + + union { + struct in6_addr a6; + struct { + uint8_t zero[10]; + uint8_t one[2]; + struct in_addr a; + } a4; + } a; + + in_port_t tap_port; + in_port_t sock_port; + + uint16_t wnd_from_tap; + uint16_t wnd_to_tap; + + uint32_t seq_to_tap; + uint32_t seq_ack_from_tap; + uint32_t seq_from_tap; + uint32_t seq_ack_to_tap; + uint32_t seq_init_from_tap; +}; + +/** + * struct tcp_splice_conn - Descriptor for a spliced TCP connection + * @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 + * @pipe_b_a: Pipe ends for splice() from @b to @a + * @events: Events observed/actions performed on connection + * @flags: Connection flags (attributes, not events) + * @a_read: Bytes read from @a (not fully written to @b in one shot) + * @a_written: Bytes written to @a (not fully written from one @b read) + * @b_read: Bytes read from @b (not fully written to @a in one shot) + * @b_written: Bytes written to @b (not fully written from one @a read) +*/ +struct tcp_splice_conn { + int a; + int pipe_a_b[2]; + int b; + int pipe_b_a[2]; + + uint8_t events; +#define SPLICE_CLOSED 0 +#define SPLICE_CONNECT BIT(0) +#define SPLICE_ESTABLISHED BIT(1) +#define A_OUT_WAIT BIT(2) +#define B_OUT_WAIT BIT(3) +#define A_FIN_RCVD BIT(4) +#define B_FIN_RCVD BIT(5) +#define A_FIN_SENT BIT(6) +#define B_FIN_SENT BIT(7) + + uint8_t flags; +#define SPLICE_V6 BIT(0) +#define SPLICE_IN_EPOLL BIT(1) +#define RCVLOWAT_SET_A BIT(2) +#define RCVLOWAT_SET_B BIT(3) +#define RCVLOWAT_ACT_A BIT(4) +#define RCVLOWAT_ACT_B BIT(5) +#define CLOSING BIT(6) + + uint32_t a_read; + uint32_t a_written; + uint32_t b_read; + uint32_t b_written; +}; + +#endif /* TCP_CONN_H */ |