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- #ifndef _IPXE_TCP_H
- #define _IPXE_TCP_H
-
- /** @file
- *
- * TCP protocol
- *
- * This file defines the iPXE TCP API.
- *
- */
-
- FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
- #include <ipxe/tcpip.h>
-
- /**
- * A TCP header
- */
- struct tcp_header {
- uint16_t src; /* Source port */
- uint16_t dest; /* Destination port */
- uint32_t seq; /* Sequence number */
- uint32_t ack; /* Acknowledgement number */
- uint8_t hlen; /* Header length (4), Reserved (4) */
- uint8_t flags; /* Reserved (2), Flags (6) */
- uint16_t win; /* Advertised window */
- uint16_t csum; /* Checksum */
- uint16_t urg; /* Urgent pointer */
- };
-
- /** @defgroup tcpopts TCP options
- * @{
- */
-
- /** End of TCP options list */
- #define TCP_OPTION_END 0
-
- /** TCP option pad */
- #define TCP_OPTION_NOP 1
-
- /** Generic TCP option */
- struct tcp_option {
- uint8_t kind;
- uint8_t length;
- } __attribute__ (( packed ));
-
- /** TCP MSS option */
- struct tcp_mss_option {
- uint8_t kind;
- uint8_t length;
- uint16_t mss;
- } __attribute__ (( packed ));
-
- /** Code for the TCP MSS option */
- #define TCP_OPTION_MSS 2
-
- /** TCP window scale option */
- struct tcp_window_scale_option {
- uint8_t kind;
- uint8_t length;
- uint8_t scale;
- } __attribute__ (( packed ));
-
- /** Padded TCP window scale option (used for sending) */
- struct tcp_window_scale_padded_option {
- uint8_t nop;
- struct tcp_window_scale_option wsopt;
- } __attribute (( packed ));
-
- /** Code for the TCP window scale option */
- #define TCP_OPTION_WS 3
-
- /** Advertised TCP window scale
- *
- * Using a scale factor of 2**9 provides for a maximum window of 32MB,
- * which is sufficient to allow Gigabit-speed transfers with a 200ms
- * RTT. The minimum advertised window is 512 bytes, which is still
- * less than a single packet.
- */
- #define TCP_RX_WINDOW_SCALE 9
-
- /** TCP selective acknowledgement permitted option */
- struct tcp_sack_permitted_option {
- uint8_t kind;
- uint8_t length;
- } __attribute__ (( packed ));
-
- /** Padded TCP selective acknowledgement permitted option (used for sending) */
- struct tcp_sack_permitted_padded_option {
- uint8_t nop[2];
- struct tcp_sack_permitted_option spopt;
- } __attribute__ (( packed ));
-
- /** Code for the TCP selective acknowledgement permitted option */
- #define TCP_OPTION_SACK_PERMITTED 4
-
- /** TCP selective acknowledgement option */
- struct tcp_sack_option {
- uint8_t kind;
- uint8_t length;
- } __attribute__ (( packed ));
-
- /** TCP selective acknowledgement block */
- struct tcp_sack_block {
- uint32_t left;
- uint32_t right;
- } __attribute__ (( packed ));
-
- /** Maximum number of selective acknowledgement blocks
- *
- * This allows for the presence of the TCP timestamp option.
- */
- #define TCP_SACK_MAX 3
-
- /** Padded TCP selective acknowledgement option (used for sending) */
- struct tcp_sack_padded_option {
- uint8_t nop[2];
- struct tcp_sack_option sackopt;
- } __attribute__ (( packed ));
-
- /** Code for the TCP selective acknowledgement option */
- #define TCP_OPTION_SACK 5
-
- /** TCP timestamp option */
- struct tcp_timestamp_option {
- uint8_t kind;
- uint8_t length;
- uint32_t tsval;
- uint32_t tsecr;
- } __attribute__ (( packed ));
-
- /** Padded TCP timestamp option (used for sending) */
- struct tcp_timestamp_padded_option {
- uint8_t nop[2];
- struct tcp_timestamp_option tsopt;
- } __attribute__ (( packed ));
-
- /** Code for the TCP timestamp option */
- #define TCP_OPTION_TS 8
-
- /** Parsed TCP options */
- struct tcp_options {
- /** Window scale option, if present */
- const struct tcp_window_scale_option *wsopt;
- /** SACK permitted option, if present */
- const struct tcp_sack_permitted_option *spopt;
- /** Timestamp option, if present */
- const struct tcp_timestamp_option *tsopt;
- };
-
- /** @} */
-
- /*
- * TCP flags
- */
- #define TCP_CWR 0x80
- #define TCP_ECE 0x40
- #define TCP_URG 0x20
- #define TCP_ACK 0x10
- #define TCP_PSH 0x08
- #define TCP_RST 0x04
- #define TCP_SYN 0x02
- #define TCP_FIN 0x01
-
- /**
- * @defgroup tcpstates TCP states
- *
- * The TCP state is defined by a combination of the flags that have
- * been sent to the peer, the flags that have been acknowledged by the
- * peer, and the flags that have been received from the peer.
- *
- * @{
- */
-
- /** TCP flags that have been sent in outgoing packets */
- #define TCP_STATE_SENT(flags) ( (flags) << 0 )
- #define TCP_FLAGS_SENT(state) ( ( (state) >> 0 ) & 0xff )
-
- /** TCP flags that have been acknowledged by the peer
- *
- * Note that this applies only to SYN and FIN.
- */
- #define TCP_STATE_ACKED(flags) ( (flags) << 8 )
- #define TCP_FLAGS_ACKED(state) ( ( (state) >> 8 ) & 0xff )
-
- /** TCP flags that have been received from the peer
- *
- * Note that this applies only to SYN and FIN, and that once SYN has
- * been received, we should always be sending ACK.
- */
- #define TCP_STATE_RCVD(flags) ( (flags) << 16 )
- #define TCP_FLAGS_RCVD(state) ( ( (state) >> 16 ) & 0xff )
-
- /** TCP flags that are currently being sent in outgoing packets */
- #define TCP_FLAGS_SENDING(state) \
- ( TCP_FLAGS_SENT ( state ) & ~TCP_FLAGS_ACKED ( state ) )
-
- /** CLOSED
- *
- * The connection has not yet been used for anything.
- */
- #define TCP_CLOSED TCP_RST
-
- /** LISTEN
- *
- * Not currently used as a state; we have no support for listening
- * connections. Given a unique value to avoid compiler warnings.
- */
- #define TCP_LISTEN 0
-
- /** SYN_SENT
- *
- * SYN has been sent, nothing has yet been received or acknowledged.
- */
- #define TCP_SYN_SENT ( TCP_STATE_SENT ( TCP_SYN ) )
-
- /** SYN_RCVD
- *
- * SYN has been sent but not acknowledged, SYN has been received.
- */
- #define TCP_SYN_RCVD ( TCP_STATE_SENT ( TCP_SYN | TCP_ACK ) | \
- TCP_STATE_RCVD ( TCP_SYN ) )
-
- /** ESTABLISHED
- *
- * SYN has been sent and acknowledged, SYN has been received.
- */
- #define TCP_ESTABLISHED ( TCP_STATE_SENT ( TCP_SYN | TCP_ACK ) | \
- TCP_STATE_ACKED ( TCP_SYN ) | \
- TCP_STATE_RCVD ( TCP_SYN ) )
-
- /** FIN_WAIT_1
- *
- * SYN has been sent and acknowledged, SYN has been received, FIN has
- * been sent but not acknowledged, FIN has not been received.
- *
- * RFC 793 shows that we can enter FIN_WAIT_1 without have had SYN
- * acknowledged, i.e. if the application closes the connection after
- * sending and receiving SYN, but before having had SYN acknowledged.
- * However, we have to *pretend* that SYN has been acknowledged
- * anyway, otherwise we end up sending SYN and FIN in the same
- * sequence number slot. Therefore, when we transition from SYN_RCVD
- * to FIN_WAIT_1, we have to remember to set TCP_STATE_ACKED(TCP_SYN)
- * and increment our sequence number.
- */
- #define TCP_FIN_WAIT_1 ( TCP_STATE_SENT ( TCP_SYN | TCP_ACK | TCP_FIN ) | \
- TCP_STATE_ACKED ( TCP_SYN ) | \
- TCP_STATE_RCVD ( TCP_SYN ) )
-
- /** FIN_WAIT_2
- *
- * SYN has been sent and acknowledged, SYN has been received, FIN has
- * been sent and acknowledged, FIN ha not been received.
- */
- #define TCP_FIN_WAIT_2 ( TCP_STATE_SENT ( TCP_SYN | TCP_ACK | TCP_FIN ) | \
- TCP_STATE_ACKED ( TCP_SYN | TCP_FIN ) | \
- TCP_STATE_RCVD ( TCP_SYN ) )
-
- /** CLOSING / LAST_ACK
- *
- * SYN has been sent and acknowledged, SYN has been received, FIN has
- * been sent but not acknowledged, FIN has been received.
- *
- * This state actually encompasses both CLOSING and LAST_ACK; they are
- * identical with the definition of state that we use. I don't
- * *believe* that they need to be distinguished.
- */
- #define TCP_CLOSING_OR_LAST_ACK \
- ( TCP_STATE_SENT ( TCP_SYN | TCP_ACK | TCP_FIN ) | \
- TCP_STATE_ACKED ( TCP_SYN ) | \
- TCP_STATE_RCVD ( TCP_SYN | TCP_FIN ) )
-
- /** TIME_WAIT
- *
- * SYN has been sent and acknowledged, SYN has been received, FIN has
- * been sent and acknowledged, FIN has been received.
- */
- #define TCP_TIME_WAIT ( TCP_STATE_SENT ( TCP_SYN | TCP_ACK | TCP_FIN ) | \
- TCP_STATE_ACKED ( TCP_SYN | TCP_FIN ) | \
- TCP_STATE_RCVD ( TCP_SYN | TCP_FIN ) )
-
- /** CLOSE_WAIT
- *
- * SYN has been sent and acknowledged, SYN has been received, FIN has
- * been received.
- */
- #define TCP_CLOSE_WAIT ( TCP_STATE_SENT ( TCP_SYN | TCP_ACK ) | \
- TCP_STATE_ACKED ( TCP_SYN ) | \
- TCP_STATE_RCVD ( TCP_SYN | TCP_FIN ) )
-
- /** Can send data in current state
- *
- * We can send data if and only if we have had our SYN acked and we
- * have not yet sent our FIN.
- */
- #define TCP_CAN_SEND_DATA(state) \
- ( ( (state) & ( TCP_STATE_ACKED ( TCP_SYN ) | \
- TCP_STATE_SENT ( TCP_FIN ) ) ) \
- == TCP_STATE_ACKED ( TCP_SYN ) )
-
- /** Have ever been fully established
- *
- * We have been fully established if we have both received a SYN and
- * had our own SYN acked.
- */
- #define TCP_HAS_BEEN_ESTABLISHED(state) \
- ( ( (state) & ( TCP_STATE_ACKED ( TCP_SYN ) | \
- TCP_STATE_RCVD ( TCP_SYN ) ) ) \
- == ( TCP_STATE_ACKED ( TCP_SYN ) | TCP_STATE_RCVD ( TCP_SYN ) ) )
-
- /** Have closed gracefully
- *
- * We have closed gracefully if we have both received a FIN and had
- * our own FIN acked.
- */
- #define TCP_CLOSED_GRACEFULLY(state) \
- ( ( (state) & ( TCP_STATE_ACKED ( TCP_FIN ) | \
- TCP_STATE_RCVD ( TCP_FIN ) ) ) \
- == ( TCP_STATE_ACKED ( TCP_FIN ) | TCP_STATE_RCVD ( TCP_FIN ) ) )
-
- /** @} */
-
- /** Mask for TCP header length field */
- #define TCP_MASK_HLEN 0xf0
-
- /** Smallest port number on which a TCP connection can listen */
- #define TCP_MIN_PORT 1
-
- /**
- * Maxmimum advertised TCP window size
- *
- * The maximum bandwidth on any link is limited by
- *
- * max_bandwidth * round_trip_time = tcp_window
- *
- * Some rough expectations for achievable bandwidths over various
- * links are:
- *
- * a) Gigabit LAN: expected bandwidth 125MB/s, typical RTT 0.5ms,
- * minimum required window 64kB
- *
- * b) Home Internet connection: expected bandwidth 10MB/s, typical
- * RTT 25ms, minimum required window 256kB
- *
- * c) WAN: expected bandwidth 2MB/s, typical RTT 100ms, minimum
- * required window 200kB.
- *
- * The maximum possible value for the TCP window size is 1GB (using
- * the maximum window scale of 2**14). However, it is advisable to
- * keep the window size as small as possible (without limiting
- * bandwidth), since in the event of a lost packet the window size
- * represents the maximum amount that will need to be retransmitted.
- *
- * We therefore choose a maximum window size of 256kB.
- */
- #define TCP_MAX_WINDOW_SIZE ( 256 * 1024 )
-
- /**
- * Path MTU
- *
- * IPv6 requires all data link layers to support a datagram size of
- * 1280 bytes. We choose to use this as our maximum transmitted
- * datagram size, on the assumption that any practical link layer we
- * encounter will allow this size. This is a very conservative
- * assumption in practice, but the impact of making such a
- * conservative assumption is insignificant since the amount of data
- * that we transmit (rather than receive) is negligible.
- *
- * We allow space within this 1280 bytes for an IPv6 header, a TCP
- * header, and a (padded) TCP timestamp option.
- */
- #define TCP_PATH_MTU \
- ( 1280 - 40 /* IPv6 */ - 20 /* TCP */ - 12 /* TCP timestamp */ )
-
- /** TCP maximum segment lifetime
- *
- * Currently set to 2 minutes, as per RFC 793.
- */
- #define TCP_MSL ( 2 * 60 * TICKS_PER_SEC )
-
- /**
- * TCP keepalive period
- *
- * We send keepalive ACKs after this period of inactivity has elapsed
- * on an established connection.
- */
- #define TCP_KEEPALIVE_DELAY ( 15 * TICKS_PER_SEC )
-
- /**
- * TCP maximum header length
- *
- */
- #define TCP_MAX_HEADER_LEN \
- ( MAX_LL_NET_HEADER_LEN + \
- sizeof ( struct tcp_header ) + \
- sizeof ( struct tcp_mss_option ) + \
- sizeof ( struct tcp_window_scale_padded_option ) + \
- sizeof ( struct tcp_timestamp_padded_option ) )
-
- /**
- * Compare TCP sequence numbers
- *
- * @v seq1 Sequence number 1
- * @v seq2 Sequence number 2
- * @ret diff Sequence difference
- *
- * Analogous to memcmp(), returns an integer less than, equal to, or
- * greater than zero if @c seq1 is found, respectively, to be before,
- * equal to, or after @c seq2.
- */
- static inline __attribute__ (( always_inline )) int32_t
- tcp_cmp ( uint32_t seq1, uint32_t seq2 ) {
- return ( ( int32_t ) ( seq1 - seq2 ) );
- }
-
- /**
- * Check if TCP sequence number lies within window
- *
- * @v seq Sequence number
- * @v start Start of window
- * @v len Length of window
- * @ret in_window Sequence number is within window
- */
- static inline int tcp_in_window ( uint32_t seq, uint32_t start,
- uint32_t len ) {
- return ( ( seq - start ) < len );
- }
-
- /** TCP finish wait time
- *
- * Currently set to one second, since we should not allow a slowly
- * responding server to substantially delay a call to shutdown().
- */
- #define TCP_FINISH_TIMEOUT ( 1 * TICKS_PER_SEC )
-
- extern struct tcpip_protocol tcp_protocol __tcpip_protocol;
-
- #endif /* _IPXE_TCP_H */
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