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/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright (c) 2021 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#ifndef TCP_INTERNAL_H
#define TCP_INTERNAL_H
#define MAX_WS 8
#define MAX_WINDOW (1 << (16 + (MAX_WS)))
#define MSS4 ROUND_DOWN(IP_MAX_MTU - \
sizeof(struct tcphdr) - \
sizeof(struct iphdr), \
sizeof(uint32_t))
#define MSS6 ROUND_DOWN(IP_MAX_MTU - \
sizeof(struct tcphdr) - \
sizeof(struct ipv6hdr), \
sizeof(uint32_t))
#define SEQ_LE(a, b) ((b) - (a) < MAX_WINDOW)
#define SEQ_LT(a, b) ((b) - (a) - 1 < MAX_WINDOW)
#define SEQ_GE(a, b) ((a) - (b) < MAX_WINDOW)
#define SEQ_GT(a, b) ((a) - (b) - 1 < MAX_WINDOW)
#define FIN (1 << 0)
#define SYN (1 << 1)
#define RST (1 << 2)
#define ACK (1 << 4)
/* Flags for internal usage */
#define DUP_ACK (1 << 5)
#define OPT_EOL 0
#define OPT_NOP 1
#define OPT_MSS 2
#define OPT_MSS_LEN 4
#define OPT_WS 3
#define OPT_WS_LEN 3
#define OPT_SACKP 4
#define OPT_SACK 5
#define OPT_TS 8
#define TAPSIDE(conn_) ((conn_)->f.pif[1] == PIF_TAP)
#define TAPFLOW(conn_) (&((conn_)->f.side[TAPSIDE(conn_)]))
#define TAP_SIDX(conn_) (FLOW_SIDX((conn_), TAPSIDE(conn_)))
#define CONN_V4(conn) (!!inany_v4(&TAPFLOW(conn)->oaddr))
#define CONN_V6(conn) (!CONN_V4(conn))
/*
* enum tcp_iov_parts - I/O vector parts for one TCP frame
* @TCP_IOV_TAP tap backend specific header
* @TCP_IOV_ETH Ethernet header
* @TCP_IOV_IP IP (v4/v6) header
* @TCP_IOV_PAYLOAD IP payload (TCP header + data)
* @TCP_NUM_IOVS the number of entries in the iovec array
*/
enum tcp_iov_parts {
TCP_IOV_TAP = 0,
TCP_IOV_ETH = 1,
TCP_IOV_IP = 2,
TCP_IOV_PAYLOAD = 3,
TCP_NUM_IOVS
};
/**
* struct tcp_payload_t - TCP header and data to send segments with payload
* @th: TCP header
* @data: TCP data
*/
struct tcp_payload_t {
struct tcphdr th;
uint8_t data[IP_MAX_MTU - sizeof(struct tcphdr)];
#ifdef __AVX2__
} __attribute__ ((packed, aligned(32))); /* For AVX2 checksum routines */
#else
} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
#endif
/**
* struct tcp_flags_t - TCP header and data to send zero-length
* segments (flags)
* @th: TCP header
* @opts TCP options
*/
struct tcp_flags_t {
struct tcphdr th;
char opts[OPT_MSS_LEN + OPT_WS_LEN + 1];
#ifdef __AVX2__
} __attribute__ ((packed, aligned(32)));
#else
} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
#endif
extern char tcp_buf_discard [MAX_WINDOW];
void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn,
unsigned long flag);
#define conn_flag(c, conn, flag) \
do { \
flow_trace(conn, "flag at %s:%i", __func__, __LINE__); \
conn_flag_do(c, conn, flag); \
} while (0)
void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn,
unsigned long event);
#define conn_event(c, conn, event) \
do { \
flow_trace(conn, "event at %s:%i", __func__, __LINE__); \
conn_event_do(c, conn, event); \
} while (0)
void tcp_rst_do(const struct ctx *c, struct tcp_tap_conn *conn);
#define tcp_rst(c, conn) \
do { \
flow_dbg((conn), "TCP reset at %s:%i", __func__, __LINE__); \
tcp_rst_do(c, conn); \
} while (0)
size_t tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
struct iovec *iov, size_t dlen,
const uint16_t *check, uint32_t seq,
bool no_tcp_csum);
int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
bool force_seq, struct tcp_info *tinfo);
int tcp_prepare_flags(const struct ctx *c, struct tcp_tap_conn *conn, int flags,
struct tcphdr *th, char *data, size_t *optlen);
#endif /* TCP_INTERNAL_H */
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