diff options
author | Michael Brown <mcb30@ipxe.org> | 2010-04-19 20:16:01 +0100 |
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committer | Michael Brown <mcb30@ipxe.org> | 2010-04-19 23:43:39 +0100 |
commit | 8406115834d38bb743e01f35bfd36e835532415e (patch) | |
tree | ee1e3106e2cdc645d911ba5643f8414b21fc4c3e /src/include/ipxe/tcp.h | |
parent | 2a36703af228bd10d50a31daec96072fe3a992a3 (diff) | |
download | ipxe-8406115834d38bb743e01f35bfd36e835532415e.tar.gz |
[build] Rename gPXE to iPXE
Access to the gpxe.org and etherboot.org domains and associated
resources has been revoked by the registrant of the domain. Work
around this problem by renaming project from gPXE to iPXE, and
updating URLs to match.
Also update README, LOG and COPYRIGHTS to remove obsolete information.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/include/ipxe/tcp.h')
-rw-r--r-- | src/include/ipxe/tcp.h | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/src/include/ipxe/tcp.h b/src/include/ipxe/tcp.h new file mode 100644 index 000000000..f834cc36e --- /dev/null +++ b/src/include/ipxe/tcp.h @@ -0,0 +1,318 @@ +#ifndef _IPXE_TCP_H +#define _IPXE_TCP_H + +/** @file + * + * TCP protocol + * + * This file defines the iPXE TCP API. + * + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#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 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 /* _IPXE_TCP_H */ |