/* SPDX-License-Identifier: GPL-2.0-or-later * Copyright Red Hat * Author: Stefano Brivio * Author: David Gibson * * 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 /** * struct tcp_tap_conn - Descriptor for a TCP connection (not spliced) * @f: Generic flow information * @in_epoll: Is the connection in the epoll set? * @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 * @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 * @faddr: Guest side forwarding address (guest's remote address) * @eport: Guest side endpoint port (guest's local port) * @fport: Guest side forwarding port (guest's remote 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 { /* Must be first element */ struct flow_common f; bool in_epoll :1; #define TCP_RETRANS_BITS 3 unsigned int retrans :TCP_RETRANS_BITS; #define TCP_MAX_RETRANS MAX_FROM_BITS(TCP_RETRANS_BITS) #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 :FD_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 :FD_REF_BITS; uint8_t flags; #define STALLED BIT(0) #define LOCAL BIT(1) #define ACTIVE_CLOSE BIT(2) #define ACK_TO_TAP_DUE BIT(3) #define ACK_FROM_TAP_DUE BIT(4) #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 inany_addr faddr; in_port_t eport; in_port_t fport; 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; }; #define SIDES 2 /** * struct tcp_splice_conn - Descriptor for a spliced TCP connection * @f: Generic flow information * @in_epoll: Is the connection in the epoll set? * @s: File descriptor for sockets * @pipe: File descriptors for pipes * @events: Events observed/actions performed on connection * @flags: Connection flags (attributes, not events) * @read: Bytes read (not fully written to other side in one shot) * @written: Bytes written (not fully written from one other side read) */ struct tcp_splice_conn { /* Must be first element */ struct flow_common f; bool in_epoll :1; int s[SIDES]; int pipe[SIDES][2]; uint8_t events; #define SPLICE_CLOSED 0 #define SPLICE_CONNECT BIT(0) #define SPLICE_ESTABLISHED BIT(1) #define OUT_WAIT_0 BIT(2) #define OUT_WAIT_1 BIT(3) #define FIN_RCVD_0 BIT(4) #define FIN_RCVD_1 BIT(5) #define FIN_SENT_0 BIT(6) #define FIN_SENT_1 BIT(7) uint8_t flags; #define SPLICE_V6 BIT(0) #define RCVLOWAT_SET_0 BIT(1) #define RCVLOWAT_SET_1 BIT(2) #define RCVLOWAT_ACT_0 BIT(3) #define RCVLOWAT_ACT_1 BIT(4) #define CLOSING BIT(5) uint32_t read[SIDES]; uint32_t written[SIDES]; }; /* Socket pools */ #define TCP_SOCK_POOL_SIZE 32 extern int init_sock_pool4 [TCP_SOCK_POOL_SIZE]; extern int init_sock_pool6 [TCP_SOCK_POOL_SIZE]; bool tcp_flow_defer(union flow *flow); bool tcp_splice_flow_defer(union flow *flow); void tcp_splice_timer(const struct ctx *c, union flow *flow); int tcp_conn_pool_sock(int pool[]); int tcp_conn_sock(const struct ctx *c, sa_family_t af); int tcp_sock_refill_pool(const struct ctx *c, int pool[], sa_family_t af); void tcp_splice_refill(const struct ctx *c); #endif /* TCP_CONN_H */