gitproxy/RTLPlayground
1
0
Fork 0
mirror of https://github.com/logicog/RTLPlayground.git synced 2026-08-30 14:52:51 +08:00
Code Issues Packages Projects Releases Wiki Activity
Files
3eb2dfe0c9151dba53b5b9b886f93c5b46318c52
RTLPlayground/uip/uipopt.h
T
d00fandd00f 4ff009dbfc uip: cap TCP MSS to 1460 to survive jumbo-MTU clients (#298) 
* uip: parenthesise UIP_LLH_LEN

The macro expands to a bare sum, so wherever it is subtracted the second term
gets added instead. UIP_TCP_MSS - and with it UIP_RECEIVE_WINDOW - therefore
comes out 24 bytes above the buffer's real capacity. UIP_APPDATA_SIZE and
UIP_REASS_BUFSIZE are wrong the same way, though neither is reachable today.

The additions, uip_buf[UIP_LLH_LEN] and friends, were right by luck.

* uip: keep the advertised MSS below the buffer edge

Deriving the MSS straight from the buffer size makes the switch advertise
exactly the segment that fills uip_buf to its last byte, and a peer that takes
it literally corrupts every large upload: the firmware image arrives fully
acknowledged, with no retransmissions on the wire, yet the CRC over the
streamed body never matches and the flash write is abandoned.

Isolated by changing nothing but the segment size, same buffer and same file:
1490-byte segments fail four times out of four, 1460-byte segments succeed,
745-byte segments succeed. Linux halves its segments against a window this
small, so only macOS on a jumbo link ever produces a full-size segment - which
is why the failure hides so well.

Where exactly the full segment breaks the stream is not pinned down yet; until
it is, the advertised MSS stays a step below the edge.

* uip: size the buffer to the largest frame the CPU port accepts

UIP_TCP_MSS derives from UIP_CONF_BUFFER_SIZE, and the buffer was large enough
for frames the hardware will never deliver, so the switch advertised a segment
size no peer could usefully reach. A client on a jumbo-MTU link took it at its
word and the oversized replies went nowhere.

Size the buffer to the ingress limit instead. ICMP bypasses MSS and so probes
the hardware directly: on a SWTGW218AS a 1502-byte payload is answered and 1503
never arrives, which puts the largest frame the NIC hands us at 1556 bytes of
uip_buf. UIP_TCP_MSS then derives to 1490, the same edge measured over TCP.

Frames above the limit are dropped by the NIC rather than written to the
buffer - an 8 kB ping leaves the switch untouched - so nothing overruns it.
Frees 644 bytes of XDATA.

* uip: trim these comments, one of which had stopped being true

The note above UIP_CONF_BUFFER_SIZE claimed the MSS derives from it as 1490.
It does not: the commit that follows pins the MSS at 1460 on purpose, a step
below that ceiling, because a segment filling the buffer to its last byte
corrupts large uploads. Left as it was, the file argued with itself.

Both blocks are shorter now. What justifies the numbers stays, which is the
ICMP measurement behind 1556 and the four-out-of-four failure behind 1460.
What went is the storytelling around them, which belongs in this thread rather
than in a config header.

* uip: derive the MSS from the buffer again, minus explicit headroom

The review asked why the buffer size and the MSS are both set by hand when one
used to follow from the other. They answer different questions, but the gap
between them is a number in its own right, so it gets a name now:
UIP_CONF_BUFFER_EXTRA, and UIP_TCP_MSS goes back to being derived.

The headroom is where the measurement lives. A segment that fills uip_buf to
its last byte corrupts large uploads: with nothing but the segment size
changing, 1490 fails four times out of four and 1460 succeeds. With the buffer
sized to the frame the NIC accepts, an extra of 30 lands on 1460.

Deriving it the other way round does not work. Sizing the buffer from a 1460
byte MSS gives 1526, which is 30 bytes under the frame the NIC actually
delivers. A 1502 byte ICMP payload occupies 1556 bytes of uip_buf and is
answered today, and it would stop fitting.

The generated image is byte for byte the same as the one with 1460 written out,
so the expression lands on the value that was measured.

---------

Co-authored-by: d00f <tokyusho@chatik.pl>
2026-08-14 06:42:36 +02:00

550 lines
14 KiB
C
Raw Blame History

/**
* \defgroup uipopt Configuration options for uIP
* @{
*
* uIP is configured using the per-project configuration file
* uipopt.h. This file contains all compile-time options for uIP and
* should be tweaked to match each specific project. The uIP
* distribution contains a documented example "uipopt.h" that can be
* copied and modified for each project.
*
* \note Most of the configuration options in the uipopt.h should not
* be changed, but rather the per-project uip-conf.h file.
*/
/**
* \file
* Configuration options for uIP.
* \author Adam Dunkels <adam@dunkels.com>
*
* This file is used for tweaking various configuration options for
* uIP. You should make a copy of this file into one of your project's
* directories instead of editing this example "uipopt.h" file that
* comes with the uIP distribution.
*/
/*
* Copyright (c) 2001-2003, Adam Dunkels.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* This file is part of the uIP TCP/IP stack.
*
* $Id: uipopt.h,v 1.4 2006/06/12 08:00:31 adam Exp $
*
*/
#ifndef __UIPOPT_H__
#define __UIPOPT_H__
#ifndef UIP_LITTLE_ENDIAN
#define UIP_LITTLE_ENDIAN 3412
#endif /* UIP_LITTLE_ENDIAN */
#ifndef UIP_BIG_ENDIAN
#define UIP_BIG_ENDIAN 1234
#endif /* UIP_BIG_ENDIAN */
#include "uip-conf.h"
/*------------------------------------------------------------------------------*/
/**
* \name Static configuration options
* @{
*
* These configuration options can be used for setting the IP address
* settings statically, but only if UIP_FIXEDADDR is set to 1. The
* configuration options for a specific node includes IP address,
* netmask and default router as well as the Ethernet address. The
* netmask, default router and Ethernet address are appliciable only
* if uIP should be run over Ethernet.
*
* All of these should be changed to suit your project.
*/
/**
* Determines if uIP should use a fixed IP address or not.
*
* If uIP should use a fixed IP address, the settings are set in the
* uipopt.h file. If not, the macros uip_sethostaddr(),
* uip_setdraddr() and uip_setnetmask() should be used instead.
*
* \hideinitializer
*/
#define UIP_FIXEDADDR 1
/**
* Ping IP address asignment.
*
* uIP uses a "ping" packets for setting its own IP address if this
* option is set. If so, uIP will start with an empty IP address and
* the destination IP address of the first incoming "ping" (ICMP echo)
* packet will be used for setting the hosts IP address.
*
* \note This works only if UIP_FIXEDADDR is 0.
*
* \hideinitializer
*/
#ifdef UIP_CONF_PINGADDRCONF
#define UIP_PINGADDRCONF UIP_CONF_PINGADDRCONF
#else /* UIP_CONF_PINGADDRCONF */
#define UIP_PINGADDRCONF 0
#endif /* UIP_CONF_PINGADDRCONF */
/**
* Specifies if the uIP ARP module should be compiled with a fixed
* Ethernet MAC address or not.
*
* If this configuration option is 0, the macro uip_setethaddr() can
* be used to specify the Ethernet address at run-time.
*
* \hideinitializer
*/
#define UIP_FIXEDETHADDR 0
/** @} */
/*------------------------------------------------------------------------------*/
/**
* \name IP configuration options
* @{
*
*/
/**
* The IP TTL (time to live) of IP packets sent by uIP.
*
* This should normally not be changed.
*/
#define UIP_TTL 64
/**
* Turn on support for IP packet reassembly.
*
* uIP supports reassembly of fragmented IP packets. This features
* requires an additonal amount of RAM to hold the reassembly buffer
* and the reassembly code size is approximately 700 bytes. The
* reassembly buffer is of the same size as the uip_buf buffer
* (configured by UIP_BUFSIZE).
*
* \note IP packet reassembly is not heavily tested.
*
* \hideinitializer
*/
#define UIP_REASSEMBLY 0
/**
* The maximum time an IP fragment should wait in the reassembly
* buffer before it is dropped.
*
*/
#define UIP_REASS_MAXAGE 40
/** @} */
/*------------------------------------------------------------------------------*/
/**
* \name UDP configuration options
* @{
*/
/**
* Toggles wether UDP support should be compiled in or not.
*
* \hideinitializer
*/
#ifdef UIP_CONF_UDP
#define UIP_UDP UIP_CONF_UDP
#else /* UIP_CONF_UDP */
#define UIP_UDP 0
#endif /* UIP_CONF_UDP */
/**
* Toggles if UDP checksums should be used or not.
*
* \note Support for UDP checksums is currently not included in uIP,
* so this option has no function.
*
* \hideinitializer
*/
#ifdef UIP_CONF_UDP_CHECKSUMS
#define UIP_UDP_CHECKSUMS UIP_CONF_UDP_CHECKSUMS
#else
#define UIP_UDP_CHECKSUMS 0
#endif
/**
* The maximum amount of concurrent UDP connections.
*
* \hideinitializer
*/
#ifdef UIP_CONF_UDP_CONNS
#define UIP_UDP_CONNS UIP_CONF_UDP_CONNS
#else /* UIP_CONF_UDP_CONNS */
#define UIP_UDP_CONNS 10
#endif /* UIP_CONF_UDP_CONNS */
/**
* The name of the function that should be called when UDP datagrams arrive.
*
* \hideinitializer
*/
/** @} */
/*------------------------------------------------------------------------------*/
/**
* \name TCP configuration options
* @{
*/
/**
* Determines if support for opening connections from uIP should be
* compiled in.
*
* If the applications that are running on top of uIP for this project
* do not need to open outgoing TCP connections, this configration
* option can be turned off to reduce the code size of uIP.
*
* \hideinitializer
*/
#define UIP_ACTIVE_OPEN 1
/**
* The maximum number of simultaneously open TCP connections.
*
* Since the TCP connections are statically allocated, turning this
* configuration knob down results in less RAM used. Each TCP
* connection requires approximatly 30 bytes of memory.
*
* \hideinitializer
*/
#ifndef UIP_CONF_MAX_CONNECTIONS
#define UIP_CONNS 10
#else /* UIP_CONF_MAX_CONNECTIONS */
#define UIP_CONNS UIP_CONF_MAX_CONNECTIONS
#endif /* UIP_CONF_MAX_CONNECTIONS */
/**
* The maximum number of simultaneously listening TCP ports.
*
* Each listening TCP port requires 2 bytes of memory.
*
* \hideinitializer
*/
#ifndef UIP_CONF_MAX_LISTENPORTS
#define UIP_LISTENPORTS 20
#else /* UIP_CONF_MAX_LISTENPORTS */
#define UIP_LISTENPORTS UIP_CONF_MAX_LISTENPORTS
#endif /* UIP_CONF_MAX_LISTENPORTS */
/**
* Determines if support for TCP urgent data notification should be
* compiled in.
*
* Urgent data (out-of-band data) is a rarely used TCP feature that
* very seldom would be required.
*
* \hideinitializer
*/
#define UIP_URGDATA 0
/**
* The initial retransmission timeout counted in timer pulses.
*
* This should not be changed.
*/
#define UIP_RTO 3
/**
* The maximum number of times a segment should be retransmitted
* before the connection should be aborted.
*
* This should not be changed.
*/
#define UIP_MAXRTX 8
/**
* The maximum number of times a SYN segment should be retransmitted
* before a connection request should be deemed to have been
* unsuccessful.
*
* This should not need to be changed.
*/
#define UIP_MAXSYNRTX 5
/**
* The TCP maximum segment size.
*/
#define UIP_TCP_MSS (UIP_BUFSIZE - UIP_LLH_LEN - UIP_TCPIP_HLEN - UIP_BUFFER_EXTRA)
/**
* The size of the advertised receiver's window.
*
* Should be set low (i.e., to the size of the uip_buf buffer) is the
* application is slow to process incoming data, or high (32768 bytes)
* if the application processes data quickly.
*
* \hideinitializer
*/
#ifndef UIP_CONF_RECEIVE_WINDOW
#define UIP_RECEIVE_WINDOW UIP_TCP_MSS
#else
#define UIP_RECEIVE_WINDOW UIP_CONF_RECEIVE_WINDOW
#endif
/**
* How long a connection should stay in the TIME_WAIT state.
*
* This configiration option has no real implication, and it should be
* left untouched.
*/
#define UIP_TIME_WAIT_TIMEOUT 120
/** @} */
/*------------------------------------------------------------------------------*/
/**
* \name ARP configuration options
* @{
*/
/**
* The size of the ARP table.
*
* This option should be set to a larger value if this uIP node will
* have many connections from the local network.
*
* \hideinitializer
*/
#ifdef UIP_CONF_ARPTAB_SIZE
#define UIP_ARPTAB_SIZE UIP_CONF_ARPTAB_SIZE
#else
#define UIP_ARPTAB_SIZE 8
#endif
/**
* The maxium age of ARP table entries measured in 10ths of seconds.
*
* An UIP_ARP_MAXAGE of 120 corresponds to 20 minutes (BSD
* default).
*/
#define UIP_ARP_MAXAGE 120
/** @} */
/*------------------------------------------------------------------------------*/
/**
* \name General configuration options
* @{
*/
/**
* The size of the uIP packet buffer.
*
* The uIP packet buffer should not be smaller than 60 bytes, and does
* not need to be larger than 1500 bytes. Lower size results in lower
* TCP throughput, larger size results in higher TCP throughput.
*
* \hideinitializer
*/
#ifndef UIP_CONF_BUFFER_SIZE
#define UIP_BUFSIZE 2000
#else /* UIP_CONF_BUFFER_SIZE */
#define UIP_BUFSIZE UIP_CONF_BUFFER_SIZE
#endif /* UIP_CONF_BUFFER_SIZE */
/**
* Bytes of uip_buf kept out of the advertised MSS.
*
* \hideinitializer
*/
#ifndef UIP_CONF_BUFFER_EXTRA
#define UIP_BUFFER_EXTRA 0
#else /* UIP_CONF_BUFFER_EXTRA */
#define UIP_BUFFER_EXTRA UIP_CONF_BUFFER_EXTRA
#endif /* UIP_CONF_BUFFER_EXTRA */
extern __xdata uint8_t uip_buf[UIP_CONF_BUFFER_SIZE+2];
/**
* Determines if statistics support should be compiled in.
*
* The statistics is useful for debugging and to show the user.
*
* \hideinitializer
*/
#ifndef UIP_CONF_STATISTICS
#define UIP_STATISTICS 0
#else /* UIP_CONF_STATISTICS */
#define UIP_STATISTICS UIP_CONF_STATISTICS
#endif /* UIP_CONF_STATISTICS */
/**
* Determines if logging of certain events should be compiled in.
*
* This is useful mostly for debugging. The function uip_log()
* must be implemented to suit the architecture of the project, if
* logging is turned on.
*
* \hideinitializer
*/
#ifndef UIP_CONF_LOGGING
#define UIP_LOGGING 0
#else /* UIP_CONF_LOGGING */
#define UIP_LOGGING UIP_CONF_LOGGING
#endif /* UIP_CONF_LOGGING */
/**
* Broadcast support.
*
* This flag configures IP broadcast support. This is useful only
* together with UDP.
*
* \hideinitializer
*
*/
#ifndef UIP_CONF_BROADCAST
#define UIP_BROADCAST 0
#else /* UIP_CONF_BROADCAST */
#define UIP_BROADCAST UIP_CONF_BROADCAST
#endif /* UIP_CONF_BROADCAST */
/**
* Print out a uIP log message.
*
* This function must be implemented by the module that uses uIP, and
* is called by uIP whenever a log message is generated.
*/
void uip_log(char *msg);
/**
* The link level header length.
*
* This is the offset into the uip_buf where the IP header can be
* found. For Ethernet, this should be set to 14. For SLIP, this
* should be set to 0.
*
* \hideinitializer
*/
#ifdef UIP_CONF_LLH_LEN
#define UIP_LLH_LEN UIP_CONF_LLH_LEN
#else /* UIP_CONF_LLH_LEN */
#define UIP_LLH_LEN (ETHER_HEADER_SIZE + RTL_FRAME_DESC_SIZE)
#endif /* UIP_CONF_LLH_LEN */
/** @} */
/*------------------------------------------------------------------------------*/
/**
* \name CPU architecture configuration
* @{
*
* The CPU architecture configuration is where the endianess of the
* CPU on which uIP is to be run is specified. Most CPUs today are
* little endian, and the most notable exception are the Motorolas
* which are big endian. The BYTE_ORDER macro should be changed to
* reflect the CPU architecture on which uIP is to be run.
*/
/**
* The byte order of the CPU architecture on which uIP is to be run.
*
* This option can be either BIG_ENDIAN (Motorola byte order) or
* LITTLE_ENDIAN (Intel byte order).
*
* \hideinitializer
*/
#ifdef UIP_CONF_BYTE_ORDER
#define UIP_BYTE_ORDER UIP_CONF_BYTE_ORDER
#else /* UIP_CONF_BYTE_ORDER */
#define UIP_BYTE_ORDER UIP_LITTLE_ENDIAN
#endif /* UIP_CONF_BYTE_ORDER */
/** @} */
/*------------------------------------------------------------------------------*/
/**
* \name Appication specific configurations
* @{
*
* An uIP application is implemented using a single application
* function that is called by uIP whenever a TCP/IP event occurs. The
* name of this function must be registered with uIP at compile time
* using the UIP_APPCALL definition.
*
* uIP applications can store the application state within the
* uip_conn structure by specifying the type of the application
* structure by typedef:ing the type uip_tcp_appstate_t and uip_udp_appstate_t.
*
* The file containing the definitions must be included in the
* uipopt.h file.
*
* The following example illustrates how this can look.
\code
void httpd_appcall(void);
#define UIP_APPCALL httpd_appcall
struct httpd_state {
u8_t state;
u16_t count;
char *dataptr;
char *script;
};
typedef struct httpd_state uip_tcp_appstate_t
\endcode
*/
/**
* \var #define UIP_APPCALL
*
* The name of the application function that uIP should call in
* response to TCP/IP events.
*
*/
/**
* \var typedef uip_tcp_appstate_t
*
* The type of the application state that is to be stored in the
* uip_conn structure. This usually is typedef:ed to a struct holding
* application state information.
*/
/**
* \var typedef uip_udp_appstate_t
*
* The type of the application state that is to be stored in the
* uip_conn structure. This usually is typedef:ed to a struct holding
* application state information.
*/
/** @} */
/** @} */
#endif /* __UIPOPT_H__ */
Reference in New Issue View Git Blame Copy Permalink