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Diffstat (limited to 'debian/grub-extras/disabled/gpxe/src/include/gpxe/tcp.h')
| -rw-r--r-- | debian/grub-extras/disabled/gpxe/src/include/gpxe/tcp.h | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/debian/grub-extras/disabled/gpxe/src/include/gpxe/tcp.h b/debian/grub-extras/disabled/gpxe/src/include/gpxe/tcp.h new file mode 100644 index 0000000..7ae7eab --- /dev/null +++ b/debian/grub-extras/disabled/gpxe/src/include/gpxe/tcp.h @@ -0,0 +1,318 @@ +#ifndef _GPXE_TCP_H +#define _GPXE_TCP_H + +/** @file + * + * TCP protocol + * + * This file defines the gPXE TCP API. + * + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#include <gpxe/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 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 { + /** MSS option, if present */ + const struct tcp_mss_option *mssopt; + /** Timestampe 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 + +/* Some IOB constants */ +#define MAX_HDR_LEN 100 +#define MAX_IOB_LEN 1500 +#define MIN_IOB_LEN MAX_HDR_LEN + 100 /* To account for padding by LL */ + +/** + * Maxmimum advertised TCP window size + * + * We estimate the TCP window size as the amount of free memory we + * have. This is not strictly accurate (since it ignores any space + * already allocated as RX buffers), but it will do for now. + * + * Since we don't store out-of-order received packets, the + * retransmission penalty is that the whole window contents must be + * resent. This suggests keeping the window size small, but bear in + * mind that the maximum bandwidth on any link is limited to + * + * max_bandwidth = ( tcp_window / round_trip_time ) + * + * With a 48kB window, which probably accurately reflects our amount + * of free memory, and a WAN RTT of say 200ms, this gives a maximum + * bandwidth of 240kB/s. This is sufficiently close to realistic that + * we will need to be careful that our advertised window doesn't end + * up limiting WAN download speeds. + * + * Finally, since the window goes into a 16-bit field and we cannot + * actually use 65536, we use a window size of (65536-4) to ensure + * that payloads remain dword-aligned. + */ +//#define TCP_MAX_WINDOW_SIZE ( 65536 - 4 ) +#define TCP_MAX_WINDOW_SIZE 4096 + +/** + * Path MTU + * + * We really ought to implement Path MTU discovery. Until we do, + * anything with a path MTU greater than this may fail. + */ +#define TCP_PATH_MTU 1460 + +/** + * Advertised TCP MSS + * + * We currently hardcode this to a reasonable value and hope that the + * sender uses path MTU discovery. The alternative is breaking the + * abstraction layer so that we can find out the MTU from the IP layer + * (which would have to find out from the net device layer). + */ +#define TCP_MSS 1460 + +/** TCP maximum segment lifetime + * + * Currently set to 2 minutes, as per RFC 793. + */ +#define TCP_MSL ( 2 * 60 * TICKS_PER_SEC ) + +extern struct tcpip_protocol tcp_protocol; + +#endif /* _GPXE_TCP_H */ |