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52d45f1737
Currently we always deliver inbound TCP packets to the guest's most recent observed IP address. This has the odd side effect that if the guest changes its IP address with active TCP connections we might deliver packets from old connections to the new address. That won't work; it will probably result in an RST from the guest. Worse, if the guest added a new address but also retains the old one, then we could break those old connections by redirecting them to the new address. Now that we maintain flowside information, we have a record of the correct guest side address and can just use it. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
100 lines
2.8 KiB
C
100 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright (c) 2021 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*/
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#ifndef TCP_INTERNAL_H
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#define TCP_INTERNAL_H
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#define MAX_WS 8
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#define MAX_WINDOW (1 << (16 + (MAX_WS)))
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#define MSS4 ROUND_DOWN(IP_MAX_MTU - \
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sizeof(struct tcphdr) - \
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sizeof(struct iphdr), \
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sizeof(uint32_t))
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#define MSS6 ROUND_DOWN(IP_MAX_MTU - \
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sizeof(struct tcphdr) - \
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sizeof(struct ipv6hdr), \
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sizeof(uint32_t))
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#define SEQ_LE(a, b) ((b) - (a) < MAX_WINDOW)
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#define SEQ_LT(a, b) ((b) - (a) - 1 < MAX_WINDOW)
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#define SEQ_GE(a, b) ((a) - (b) < MAX_WINDOW)
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#define SEQ_GT(a, b) ((a) - (b) - 1 < MAX_WINDOW)
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#define FIN (1 << 0)
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#define SYN (1 << 1)
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#define RST (1 << 2)
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#define ACK (1 << 4)
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/* Flags for internal usage */
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#define DUP_ACK (1 << 5)
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#define OPT_EOL 0
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#define OPT_NOP 1
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#define OPT_MSS 2
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#define OPT_MSS_LEN 4
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#define OPT_WS 3
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#define OPT_WS_LEN 3
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#define OPT_SACKP 4
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#define OPT_SACK 5
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#define OPT_TS 8
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#define TAPSIDE(conn_) ((conn_)->f.pif[1] == PIF_TAP)
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#define TAPFLOW(conn_) (&((conn_)->f.side[TAPSIDE(conn_)]))
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#define CONN_V4(conn) (!!inany_v4(&TAPFLOW(conn)->faddr))
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#define CONN_V6(conn) (!CONN_V4(conn))
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/*
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* enum tcp_iov_parts - I/O vector parts for one TCP frame
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* @TCP_IOV_TAP tap backend specific header
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* @TCP_IOV_ETH Ethernet header
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* @TCP_IOV_IP IP (v4/v6) header
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* @TCP_IOV_PAYLOAD IP payload (TCP header + data)
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* @TCP_NUM_IOVS the number of entries in the iovec array
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*/
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enum tcp_iov_parts {
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TCP_IOV_TAP = 0,
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TCP_IOV_ETH = 1,
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TCP_IOV_IP = 2,
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TCP_IOV_PAYLOAD = 3,
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TCP_NUM_IOVS
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};
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extern char tcp_buf_discard [MAX_WINDOW];
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void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn,
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unsigned long flag);
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#define conn_flag(c, conn, flag) \
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do { \
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flow_trace(conn, "flag at %s:%i", __func__, __LINE__); \
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conn_flag_do(c, conn, flag); \
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} while (0)
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void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn,
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unsigned long event);
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#define conn_event(c, conn, event) \
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do { \
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flow_trace(conn, "event at %s:%i", __func__, __LINE__); \
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conn_event_do(c, conn, event); \
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} while (0)
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void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn);
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#define tcp_rst(c, conn) \
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do { \
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flow_dbg((conn), "TCP reset at %s:%i", __func__, __LINE__); \
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tcp_rst_do(c, conn); \
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} while (0)
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size_t tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
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struct iovec *iov, size_t dlen,
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const uint16_t *check, uint32_t seq);
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int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
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int force_seq, struct tcp_info *tinfo);
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int tcp_prepare_flags(struct ctx *c, struct tcp_tap_conn *conn, int flags,
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struct tcphdr *th, char *data, size_t *optlen);
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#endif /* TCP_INTERNAL_H */
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