motify compile link error

motify compile link error
This commit is contained in:
ant 2016-09-18 09:03:25 +08:00
parent 923914edae
commit 03e74a8e50
5418 changed files with 1367914 additions and 206149 deletions

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@ -1,6 +1,6 @@
savannah.txt - How to obtain the current development source code.
contrib.txt - How to contribute to lwIP as a developer.
rawapi.txt - The documentation for the core API of lwIP.
Also provides an overview about the other APIs and multithreading.
snmp_agent.txt - The documentation for the lwIP SNMP agent.
sys_arch.txt - The documentation for a system abstraction layer of lwIP.
savannah.txt - How to obtain the current development source code.
contrib.txt - How to contribute to lwIP as a developer.
rawapi.txt - The documentation for the core API of lwIP.
Also provides an overview about the other APIs and multithreading.
snmp_agent.txt - The documentation for the lwIP SNMP agent.
sys_arch.txt - The documentation for a system abstraction layer of lwIP.

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@ -1,63 +1,63 @@
1 Introduction
This document describes some guidelines for people participating
in lwIP development.
2 How to contribute to lwIP
Here is a short list of suggestions to anybody working with lwIP and
trying to contribute bug reports, fixes, enhancements, platform ports etc.
First of all as you may already know lwIP is a volunteer project so feedback
to fixes or questions might often come late. Hopefully the bug and patch tracking
features of Savannah help us not lose users' input.
2.1 Source code style:
1. do not use tabs.
2. indentation is two spaces per level (i.e. per tab).
3. end debug messages with a trailing newline (\n).
4. one space between keyword and opening bracket.
5. no space between function and opening bracket.
6. one space and no newline before opening curly braces of a block.
7. closing curly brace on a single line.
8. spaces surrounding assignment and comparisons.
9. don't initialize static and/or global variables to zero, the compiler takes care of that.
10. use current source code style as further reference.
2.2 Source code documentation style:
1. JavaDoc compliant and Doxygen compatible.
2. Function documentation above functions in .c files, not .h files.
(This forces you to synchronize documentation and implementation.)
3. Use current documentation style as further reference.
2.3 Bug reports and patches:
1. Make sure you are reporting bugs or send patches against the latest
sources. (From the latest release and/or the current CVS sources.)
2. If you think you found a bug make sure it's not already filed in the
bugtracker at Savannah.
3. If you have a fix put the patch on Savannah. If it is a patch that affects
both core and arch specific stuff please separate them so that the core can
be applied separately while leaving the other patch 'open'. The prefered way
is to NOT touch archs you can't test and let maintainers take care of them.
This is a good way to see if they are used at all - the same goes for unix
netifs except tapif.
4. Do not file a bug and post a fix to it to the patch area. Either a bug report
or a patch will be enough.
If you correct an existing bug then attach the patch to the bug rather than creating a new entry in the patch area.
5. Trivial patches (compiler warning, indentation and spelling fixes or anything obvious which takes a line or two)
can go to the lwip-users list. This is still the fastest way of interaction and the list is not so crowded
as to allow for loss of fixes. Putting bugs on Savannah and subsequently closing them is too much an overhead
for reporting a compiler warning fix.
6. Patches should be specific to a single change or to related changes.Do not mix bugfixes with spelling and other
trivial fixes unless the bugfix is trivial too.Do not reorganize code and rename identifiers in the same patch you
change behaviour if not necessary.A patch is easier to read and understand if it's to the point and short than
if it's not to the point and long :) so the chances for it to be applied are greater.
2.4 Platform porters:
1. If you have ported lwIP to a platform (an OS, a uC/processor or a combination of these) and
you think it could benefit others[1] you might want discuss this on the mailing list. You
can also ask for CVS access to submit and maintain your port in the contrib CVS module.
1 Introduction
This document describes some guidelines for people participating
in lwIP development.
2 How to contribute to lwIP
Here is a short list of suggestions to anybody working with lwIP and
trying to contribute bug reports, fixes, enhancements, platform ports etc.
First of all as you may already know lwIP is a volunteer project so feedback
to fixes or questions might often come late. Hopefully the bug and patch tracking
features of Savannah help us not lose users' input.
2.1 Source code style:
1. do not use tabs.
2. indentation is two spaces per level (i.e. per tab).
3. end debug messages with a trailing newline (\n).
4. one space between keyword and opening bracket.
5. no space between function and opening bracket.
6. one space and no newline before opening curly braces of a block.
7. closing curly brace on a single line.
8. spaces surrounding assignment and comparisons.
9. don't initialize static and/or global variables to zero, the compiler takes care of that.
10. use current source code style as further reference.
2.2 Source code documentation style:
1. JavaDoc compliant and Doxygen compatible.
2. Function documentation above functions in .c files, not .h files.
(This forces you to synchronize documentation and implementation.)
3. Use current documentation style as further reference.
2.3 Bug reports and patches:
1. Make sure you are reporting bugs or send patches against the latest
sources. (From the latest release and/or the current CVS sources.)
2. If you think you found a bug make sure it's not already filed in the
bugtracker at Savannah.
3. If you have a fix put the patch on Savannah. If it is a patch that affects
both core and arch specific stuff please separate them so that the core can
be applied separately while leaving the other patch 'open'. The prefered way
is to NOT touch archs you can't test and let maintainers take care of them.
This is a good way to see if they are used at all - the same goes for unix
netifs except tapif.
4. Do not file a bug and post a fix to it to the patch area. Either a bug report
or a patch will be enough.
If you correct an existing bug then attach the patch to the bug rather than creating a new entry in the patch area.
5. Trivial patches (compiler warning, indentation and spelling fixes or anything obvious which takes a line or two)
can go to the lwip-users list. This is still the fastest way of interaction and the list is not so crowded
as to allow for loss of fixes. Putting bugs on Savannah and subsequently closing them is too much an overhead
for reporting a compiler warning fix.
6. Patches should be specific to a single change or to related changes.Do not mix bugfixes with spelling and other
trivial fixes unless the bugfix is trivial too.Do not reorganize code and rename identifiers in the same patch you
change behaviour if not necessary.A patch is easier to read and understand if it's to the point and short than
if it's not to the point and long :) so the chances for it to be applied are greater.
2.4 Platform porters:
1. If you have ported lwIP to a platform (an OS, a uC/processor or a combination of these) and
you think it could benefit others[1] you might want discuss this on the mailing list. You
can also ask for CVS access to submit and maintain your port in the contrib CVS module.

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Daily Use Guide for using Savannah for lwIP
Table of Contents:
1 - Obtaining lwIP from the CVS repository
2 - Committers/developers CVS access using SSH (to be written)
3 - Merging from DEVEL branch to main trunk (stable branch)
4 - How to release lwIP
1 Obtaining lwIP from the CVS repository
----------------------------------------
To perform an anonymous CVS checkout of the main trunk (this is where
bug fixes and incremental enhancements occur), do this:
cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout lwip
Or, obtain a stable branch (updated with bug fixes only) as follows:
cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout \
-r STABLE-0_7 -d lwip-0.7 lwip
Or, obtain a specific (fixed) release as follows:
cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout \
-r STABLE-0_7_0 -d lwip-0.7.0 lwip
3 Committers/developers CVS access using SSH
--------------------------------------------
The Savannah server uses SSH (Secure Shell) protocol 2 authentication and encryption.
As such, CVS commits to the server occur through a SSH tunnel for project members.
To create a SSH2 key pair in UNIX-like environments, do this:
ssh-keygen -t dsa
Under Windows, a recommended SSH client is "PuTTY", freely available with good
documentation and a graphic user interface. Use its key generator.
Now paste the id_dsa.pub contents into your Savannah account public key list. Wait
a while so that Savannah can update its configuration (This can take minutes).
Try to login using SSH:
ssh -v your_login@cvs.sv.gnu.org
If it tells you:
Authenticating with public key "your_key_name"...
Server refused to allocate pty
then you could login; Savannah refuses to give you a shell - which is OK, as we
are allowed to use SSH for CVS only. Now, you should be able to do this:
export CVS_RSH=ssh
cvs -z3 -d:ext:your_login@cvs.sv.gnu.org:/sources/lwip co lwip
after which you can edit your local files with bug fixes or new features and
commit them. Make sure you know what you are doing when using CVS to make
changes on the repository. If in doubt, ask on the lwip-members mailing list.
(If SSH asks about authenticity of the host, you can check the key
fingerprint against http://savannah.nongnu.org/cvs/?group=lwip)
3 Merging from DEVEL branch to main trunk (stable)
--------------------------------------------------
Merging is a delicate process in CVS and requires the
following disciplined steps in order to prevent conflicts
in the future. Conflicts can be hard to solve!
Merging from branch A to branch B requires that the A branch
has a tag indicating the previous merger. This tag is called
'merged_from_A_to_B'. After merging, the tag is moved in the
A branch to remember this merger for future merge actions.
IMPORTANT: AFTER COMMITTING A SUCCESFUL MERGE IN THE
REPOSITORY, THE TAG MUST BE SET ON THE SOURCE BRANCH OF THE
MERGE ACTION (REPLACING EXISTING TAGS WITH THE SAME NAME).
Merge all changes in DEVEL since our last merge to main:
In the working copy of the main trunk:
cvs update -P -jmerged_from_DEVEL_to_main -jDEVEL
(This will apply the changes between 'merged_from_DEVEL_to_main'
and 'DEVEL' to your work set of files)
We can now commit the merge result.
cvs commit -R -m "Merged from DEVEL to main."
If this worked out OK, we now move the tag in the DEVEL branch
to this merge point, so we can use this point for future merges:
cvs rtag -F -r DEVEL merged_from_DEVEL_to_main lwip
4 How to release lwIP
---------------------
First, checkout a clean copy of the branch to be released. Tag this set with
tag name "STABLE-0_6_3". (I use release number 0.6.3 throughout this example).
Login CVS using pserver authentication, then export a clean copy of the
tagged tree. Export is similar to a checkout, except that the CVS metadata
is not created locally.
export CVS_RSH=ssh
cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout \
-r STABLE-0_6_3 -d lwip-0.6.3 lwip
Archive this directory using tar, gzip'd, bzip2'd and zip'd.
tar czvf lwip-0.6.3.tar.gz lwip-0.6.3
tar cjvf lwip-0.6.3.tar.bz2 lwip-0.6.3
zip -r lwip-0.6.3.zip lwip-0.6.3
Now, sign the archives with a detached GPG binary signature as follows:
gpg -b lwip-0.6.3.tar.gz
gpg -b lwip-0.6.3.tar.bz2
gpg -b lwip-0.6.3.zip
Upload these files using anonymous FTP:
ncftp ftp://savannah.gnu.org/incoming/savannah/lwip
ncftp>mput *0.6.3.*
Additionally, you may post a news item on Savannah, like this:
A new 0.6.3 release is now available here:
http://savannah.nongnu.org/files/?group=lwip&highlight=0.6.3
You will have to submit this via the user News interface, then approve
Daily Use Guide for using Savannah for lwIP
Table of Contents:
1 - Obtaining lwIP from the CVS repository
2 - Committers/developers CVS access using SSH (to be written)
3 - Merging from DEVEL branch to main trunk (stable branch)
4 - How to release lwIP
1 Obtaining lwIP from the CVS repository
----------------------------------------
To perform an anonymous CVS checkout of the main trunk (this is where
bug fixes and incremental enhancements occur), do this:
cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout lwip
Or, obtain a stable branch (updated with bug fixes only) as follows:
cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout \
-r STABLE-0_7 -d lwip-0.7 lwip
Or, obtain a specific (fixed) release as follows:
cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout \
-r STABLE-0_7_0 -d lwip-0.7.0 lwip
3 Committers/developers CVS access using SSH
--------------------------------------------
The Savannah server uses SSH (Secure Shell) protocol 2 authentication and encryption.
As such, CVS commits to the server occur through a SSH tunnel for project members.
To create a SSH2 key pair in UNIX-like environments, do this:
ssh-keygen -t dsa
Under Windows, a recommended SSH client is "PuTTY", freely available with good
documentation and a graphic user interface. Use its key generator.
Now paste the id_dsa.pub contents into your Savannah account public key list. Wait
a while so that Savannah can update its configuration (This can take minutes).
Try to login using SSH:
ssh -v your_login@cvs.sv.gnu.org
If it tells you:
Authenticating with public key "your_key_name"...
Server refused to allocate pty
then you could login; Savannah refuses to give you a shell - which is OK, as we
are allowed to use SSH for CVS only. Now, you should be able to do this:
export CVS_RSH=ssh
cvs -z3 -d:ext:your_login@cvs.sv.gnu.org:/sources/lwip co lwip
after which you can edit your local files with bug fixes or new features and
commit them. Make sure you know what you are doing when using CVS to make
changes on the repository. If in doubt, ask on the lwip-members mailing list.
(If SSH asks about authenticity of the host, you can check the key
fingerprint against http://savannah.nongnu.org/cvs/?group=lwip)
3 Merging from DEVEL branch to main trunk (stable)
--------------------------------------------------
Merging is a delicate process in CVS and requires the
following disciplined steps in order to prevent conflicts
in the future. Conflicts can be hard to solve!
Merging from branch A to branch B requires that the A branch
has a tag indicating the previous merger. This tag is called
'merged_from_A_to_B'. After merging, the tag is moved in the
A branch to remember this merger for future merge actions.
IMPORTANT: AFTER COMMITTING A SUCCESFUL MERGE IN THE
REPOSITORY, THE TAG MUST BE SET ON THE SOURCE BRANCH OF THE
MERGE ACTION (REPLACING EXISTING TAGS WITH THE SAME NAME).
Merge all changes in DEVEL since our last merge to main:
In the working copy of the main trunk:
cvs update -P -jmerged_from_DEVEL_to_main -jDEVEL
(This will apply the changes between 'merged_from_DEVEL_to_main'
and 'DEVEL' to your work set of files)
We can now commit the merge result.
cvs commit -R -m "Merged from DEVEL to main."
If this worked out OK, we now move the tag in the DEVEL branch
to this merge point, so we can use this point for future merges:
cvs rtag -F -r DEVEL merged_from_DEVEL_to_main lwip
4 How to release lwIP
---------------------
First, checkout a clean copy of the branch to be released. Tag this set with
tag name "STABLE-0_6_3". (I use release number 0.6.3 throughout this example).
Login CVS using pserver authentication, then export a clean copy of the
tagged tree. Export is similar to a checkout, except that the CVS metadata
is not created locally.
export CVS_RSH=ssh
cvs -z3 -d:pserver:anonymous@cvs.sv.gnu.org:/sources/lwip checkout \
-r STABLE-0_6_3 -d lwip-0.6.3 lwip
Archive this directory using tar, gzip'd, bzip2'd and zip'd.
tar czvf lwip-0.6.3.tar.gz lwip-0.6.3
tar cjvf lwip-0.6.3.tar.bz2 lwip-0.6.3
zip -r lwip-0.6.3.zip lwip-0.6.3
Now, sign the archives with a detached GPG binary signature as follows:
gpg -b lwip-0.6.3.tar.gz
gpg -b lwip-0.6.3.tar.bz2
gpg -b lwip-0.6.3.zip
Upload these files using anonymous FTP:
ncftp ftp://savannah.gnu.org/incoming/savannah/lwip
ncftp>mput *0.6.3.*
Additionally, you may post a news item on Savannah, like this:
A new 0.6.3 release is now available here:
http://savannah.nongnu.org/files/?group=lwip&highlight=0.6.3
You will have to submit this via the user News interface, then approve
this via the Administrator News interface.

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@ -1,181 +1,181 @@
SNMPv1 agent for lwIP
Author: Christiaan Simons
This is a brief introduction how to use and configure the SNMP agent.
Note the agent uses the raw-API UDP interface so you may also want to
read rawapi.txt to gain a better understanding of the SNMP message handling.
0 Agent Capabilities
====================
SNMPv1 per RFC1157
This is an old(er) standard but is still widely supported.
For SNMPv2c and v3 have a greater complexity and need many
more lines of code. IMHO this breaks the idea of "lightweight IP".
Note the S in SNMP stands for "Simple". Note that "Simple" is
relative. SNMP is simple compared to the complex ISO network
management protocols CMIP (Common Management Information Protocol)
and CMOT (CMip Over Tcp).
MIB II per RFC1213
The standard lwIP stack management information base.
This is a required MIB, so this is always enabled.
When builing lwIP without TCP, the mib-2.tcp group is omitted.
The groups EGP, CMOT and transmission are disabled by default.
Most mib-2 objects are not writable except:
sysName, sysLocation, sysContact, snmpEnableAuthenTraps.
Writing to or changing the ARP and IP address and route
tables is not possible.
Note lwIP has a very limited notion of IP routing. It currently
doen't have a route table and doesn't have a notion of the U,G,H flags.
Instead lwIP uses the interface list with only one default interface
acting as a single gateway interface (G) for the default route.
The agent returns a "virtual table" with the default route 0.0.0.0
for the default interface and network routes (no H) for each
network interface in the netif_list.
All routes are considered to be up (U).
Loading additional MIBs
MIBs can only be added in compile-time, not in run-time.
There is no MIB compiler thus additional MIBs must be hand coded.
Large SNMP message support
The packet decoding and encoding routines are designed
to use pbuf-chains. Larger payloads than the minimum
SNMP requirement of 484 octets are supported if the
PBUF_POOL_SIZE and IP_REASS_BUFSIZE are set to match your
local requirement.
1 Building the Agent
====================
First of all you'll need to add the following define
to your local lwipopts.h:
#define LWIP_SNMP 1
and add the source files in lwip/src/core/snmp
and some snmp headers in lwip/src/include/lwip to your makefile.
Note you'll might need to adapt you network driver to update
the mib2 variables for your interface.
2 Running the Agent
===================
The following function calls must be made in your program to
actually get the SNMP agent running.
Before starting the agent you should supply pointers
to non-volatile memory for sysContact, sysLocation,
and snmpEnableAuthenTraps. You can do this by calling
snmp_set_syscontact()
snmp_set_syslocation()
snmp_set_snmpenableauthentraps()
Additionally you may want to set
snmp_set_sysdescr()
snmp_set_sysobjid() (if you have a private MIB)
snmp_set_sysname()
Also before starting the agent you need to setup
one or more trap destinations using these calls:
snmp_trap_dst_enable();
snmp_trap_dst_ip_set();
In the lwIP initialisation sequence call snmp_init() just after
the call to udp_init().
Exactly every 10 msec the SNMP uptime timestamp must be updated with
snmp_inc_sysuptime(). You should call this from a timer interrupt
or a timer signal handler depending on your runtime environment.
An alternative way to update the SNMP uptime timestamp is to do a call like
snmp_add_sysuptime(100) each 1000ms (which is bigger "step", but call to
a lower frequency). Another one is to not call snmp_inc_sysuptime() or
snmp_add_sysuptime(), and to define the SNMP_GET_SYSUPTIME(sysuptime) macro.
This one is undefined by default in mib2.c. SNMP_GET_SYSUPTIME is called inside
snmp_get_sysuptime(u32_t *value), and enable to change "sysuptime" value only
when it's queried (any function which need "sysuptime" have to call
snmp_get_sysuptime).
3 Private MIBs
==============
If want to extend the agent with your own private MIB you'll need to
add the following define to your local lwipopts.h:
#define SNMP_PRIVATE_MIB 1
You must provide the private_mib.h and associated files yourself.
Note we don't have a "MIB compiler" that generates C source from a MIB,
so you're required to do some serious coding if you enable this!
Note the lwIP enterprise ID (26381) is assigned to the lwIP project,
ALL OBJECT IDENTIFIERS LIVING UNDER THIS ID ARE ASSIGNED BY THE lwIP
MAINTAINERS!
If you need to create your own private MIB you'll need
to apply for your own enterprise ID with IANA: http://www.iana.org/numbers.html
You can set it by passing a struct snmp_obj_id to the agent
using snmp_set_sysobjid(&my_object_id), just before snmp_init().
Note the object identifiers for thes MIB-2 and your private MIB
tree must be kept in sorted ascending (lexicographical) order.
This to ensure correct getnext operation.
An example for a private MIB is part of the "minimal Unix" project:
contrib/ports/unix/proj/minimal/lwip_prvmib.c
The next chapter gives a more detailed description of the
MIB-2 tree and the optional private MIB.
4 The Gory Details
==================
4.0 Object identifiers and the MIB tree.
We have three distinct parts for all object identifiers:
The prefix
.iso.org.dod.internet
the middle part
.mgmt.mib-2.ip.ipNetToMediaTable.ipNetToMediaEntry.ipNetToMediaPhysAddress
and the index part
.1.192.168.0.1
Objects located above the .internet hierarchy aren't supported.
Currently only the .mgmt sub-tree is available and
when the SNMP_PRIVATE_MIB is enabled the .private tree
becomes available too.
Object identifiers from incoming requests are checked
for a matching prefix, middle part and index part
or are expanded(*) for GetNext requests with short
or inexisting names in the request.
(* we call this "expansion" but this also
resembles the "auto-completion" operation)
The middle part is usually located in ROM (const)
to preserve precious RAM on small microcontrollers.
However RAM location is possible for a dynamically
changing private tree.
The index part is handled by functions which in
turn use dynamically allocated index trees from RAM.
These trees are updated by e.g. the etharp code
when new entries are made or removed form the ARP cache.
/** @todo more gory details */
SNMPv1 agent for lwIP
Author: Christiaan Simons
This is a brief introduction how to use and configure the SNMP agent.
Note the agent uses the raw-API UDP interface so you may also want to
read rawapi.txt to gain a better understanding of the SNMP message handling.
0 Agent Capabilities
====================
SNMPv1 per RFC1157
This is an old(er) standard but is still widely supported.
For SNMPv2c and v3 have a greater complexity and need many
more lines of code. IMHO this breaks the idea of "lightweight IP".
Note the S in SNMP stands for "Simple". Note that "Simple" is
relative. SNMP is simple compared to the complex ISO network
management protocols CMIP (Common Management Information Protocol)
and CMOT (CMip Over Tcp).
MIB II per RFC1213
The standard lwIP stack management information base.
This is a required MIB, so this is always enabled.
When builing lwIP without TCP, the mib-2.tcp group is omitted.
The groups EGP, CMOT and transmission are disabled by default.
Most mib-2 objects are not writable except:
sysName, sysLocation, sysContact, snmpEnableAuthenTraps.
Writing to or changing the ARP and IP address and route
tables is not possible.
Note lwIP has a very limited notion of IP routing. It currently
doen't have a route table and doesn't have a notion of the U,G,H flags.
Instead lwIP uses the interface list with only one default interface
acting as a single gateway interface (G) for the default route.
The agent returns a "virtual table" with the default route 0.0.0.0
for the default interface and network routes (no H) for each
network interface in the netif_list.
All routes are considered to be up (U).
Loading additional MIBs
MIBs can only be added in compile-time, not in run-time.
There is no MIB compiler thus additional MIBs must be hand coded.
Large SNMP message support
The packet decoding and encoding routines are designed
to use pbuf-chains. Larger payloads than the minimum
SNMP requirement of 484 octets are supported if the
PBUF_POOL_SIZE and IP_REASS_BUFSIZE are set to match your
local requirement.
1 Building the Agent
====================
First of all you'll need to add the following define
to your local lwipopts.h:
#define LWIP_SNMP 1
and add the source files in lwip/src/core/snmp
and some snmp headers in lwip/src/include/lwip to your makefile.
Note you'll might need to adapt you network driver to update
the mib2 variables for your interface.
2 Running the Agent
===================
The following function calls must be made in your program to
actually get the SNMP agent running.
Before starting the agent you should supply pointers
to non-volatile memory for sysContact, sysLocation,
and snmpEnableAuthenTraps. You can do this by calling
snmp_set_syscontact()
snmp_set_syslocation()
snmp_set_snmpenableauthentraps()
Additionally you may want to set
snmp_set_sysdescr()
snmp_set_sysobjid() (if you have a private MIB)
snmp_set_sysname()
Also before starting the agent you need to setup
one or more trap destinations using these calls:
snmp_trap_dst_enable();
snmp_trap_dst_ip_set();
In the lwIP initialisation sequence call snmp_init() just after
the call to udp_init().
Exactly every 10 msec the SNMP uptime timestamp must be updated with
snmp_inc_sysuptime(). You should call this from a timer interrupt
or a timer signal handler depending on your runtime environment.
An alternative way to update the SNMP uptime timestamp is to do a call like
snmp_add_sysuptime(100) each 1000ms (which is bigger "step", but call to
a lower frequency). Another one is to not call snmp_inc_sysuptime() or
snmp_add_sysuptime(), and to define the SNMP_GET_SYSUPTIME(sysuptime) macro.
This one is undefined by default in mib2.c. SNMP_GET_SYSUPTIME is called inside
snmp_get_sysuptime(u32_t *value), and enable to change "sysuptime" value only
when it's queried (any function which need "sysuptime" have to call
snmp_get_sysuptime).
3 Private MIBs
==============
If want to extend the agent with your own private MIB you'll need to
add the following define to your local lwipopts.h:
#define SNMP_PRIVATE_MIB 1
You must provide the private_mib.h and associated files yourself.
Note we don't have a "MIB compiler" that generates C source from a MIB,
so you're required to do some serious coding if you enable this!
Note the lwIP enterprise ID (26381) is assigned to the lwIP project,
ALL OBJECT IDENTIFIERS LIVING UNDER THIS ID ARE ASSIGNED BY THE lwIP
MAINTAINERS!
If you need to create your own private MIB you'll need
to apply for your own enterprise ID with IANA: http://www.iana.org/numbers.html
You can set it by passing a struct snmp_obj_id to the agent
using snmp_set_sysobjid(&my_object_id), just before snmp_init().
Note the object identifiers for thes MIB-2 and your private MIB
tree must be kept in sorted ascending (lexicographical) order.
This to ensure correct getnext operation.
An example for a private MIB is part of the "minimal Unix" project:
contrib/ports/unix/proj/minimal/lwip_prvmib.c
The next chapter gives a more detailed description of the
MIB-2 tree and the optional private MIB.
4 The Gory Details
==================
4.0 Object identifiers and the MIB tree.
We have three distinct parts for all object identifiers:
The prefix
.iso.org.dod.internet
the middle part
.mgmt.mib-2.ip.ipNetToMediaTable.ipNetToMediaEntry.ipNetToMediaPhysAddress
and the index part
.1.192.168.0.1
Objects located above the .internet hierarchy aren't supported.
Currently only the .mgmt sub-tree is available and
when the SNMP_PRIVATE_MIB is enabled the .private tree
becomes available too.
Object identifiers from incoming requests are checked
for a matching prefix, middle part and index part
or are expanded(*) for GetNext requests with short
or inexisting names in the request.
(* we call this "expansion" but this also
resembles the "auto-completion" operation)
The middle part is usually located in ROM (const)
to preserve precious RAM on small microcontrollers.
However RAM location is possible for a dynamically
changing private tree.
The index part is handled by functions which in
turn use dynamically allocated index trees from RAM.
These trees are updated by e.g. the etharp code
when new entries are made or removed form the ARP cache.
/** @todo more gory details */

View file

@ -1,267 +1,267 @@
sys_arch interface for lwIP 0.6++
Author: Adam Dunkels
The operating system emulation layer provides a common interface
between the lwIP code and the underlying operating system kernel. The
general idea is that porting lwIP to new architectures requires only
small changes to a few header files and a new sys_arch
implementation. It is also possible to do a sys_arch implementation
that does not rely on any underlying operating system.
The sys_arch provides semaphores and mailboxes to lwIP. For the full
lwIP functionality, multiple threads support can be implemented in the
sys_arch, but this is not required for the basic lwIP
functionality. Previous versions of lwIP required the sys_arch to
implement timer scheduling as well but as of lwIP 0.5 this is
implemented in a higher layer.
In addition to the source file providing the functionality of sys_arch,
the OS emulation layer must provide several header files defining
macros used throughout lwip. The files required and the macros they
must define are listed below the sys_arch description.
Semaphores can be either counting or binary - lwIP works with both
kinds. Mailboxes are used for message passing and can be implemented
either as a queue which allows multiple messages to be posted to a
mailbox, or as a rendez-vous point where only one message can be
posted at a time. lwIP works with both kinds, but the former type will
be more efficient. A message in a mailbox is just a pointer, nothing
more.
Semaphores are represented by the type "sys_sem_t" which is typedef'd
in the sys_arch.h file. Mailboxes are equivalently represented by the
type "sys_mbox_t". lwIP does not place any restrictions on how
sys_sem_t or sys_mbox_t are represented internally.
Since lwIP 1.4.0, semaphore and mailbox functions are prototyped in a way that
allows both using pointers or actual OS structures to be used. This way, memory
required for such types can be either allocated in place (globally or on the
stack) or on the heap (allocated internally in the "*_new()" functions).
The following functions must be implemented by the sys_arch:
- void sys_init(void)
Is called to initialize the sys_arch layer.
- err_t sys_sem_new(sys_sem_t *sem, u8_t count)
Creates a new semaphore. The semaphore is allocated to the memory that 'sem'
points to (which can be both a pointer or the actual OS structure).
The "count" argument specifies the initial state of the semaphore (which is
either 0 or 1).
If the semaphore has been created, ERR_OK should be returned. Returning any
other error will provide a hint what went wrong, but except for assertions,
no real error handling is implemented.
- void sys_sem_free(sys_sem_t *sem)
Deallocates a semaphore.
- void sys_sem_signal(sys_sem_t *sem)
Signals a semaphore.
- u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout)
Blocks the thread while waiting for the semaphore to be
signaled. If the "timeout" argument is non-zero, the thread should
only be blocked for the specified time (measured in
milliseconds). If the "timeout" argument is zero, the thread should be
blocked until the semaphore is signalled.
If the timeout argument is non-zero, the return value is the number of
milliseconds spent waiting for the semaphore to be signaled. If the
semaphore wasn't signaled within the specified time, the return value is
SYS_ARCH_TIMEOUT. If the thread didn't have to wait for the semaphore
(i.e., it was already signaled), the function may return zero.
Notice that lwIP implements a function with a similar name,
sys_sem_wait(), that uses the sys_arch_sem_wait() function.
- int sys_sem_valid(sys_sem_t *sem)
Returns 1 if the semaphore is valid, 0 if it is not valid.
When using pointers, a simple way is to check the pointer for != NULL.
When directly using OS structures, implementing this may be more complex.
This may also be a define, in which case the function is not prototyped.
- void sys_sem_set_invalid(sys_sem_t *sem)
Invalidate a semaphore so that sys_sem_valid() returns 0.
ATTENTION: This does NOT mean that the semaphore shall be deallocated:
sys_sem_free() is always called before calling this function!
This may also be a define, in which case the function is not prototyped.
- err_t sys_mbox_new(sys_mbox_t *mbox, int size)
Creates an empty mailbox for maximum "size" elements. Elements stored
in mailboxes are pointers. You have to define macros "_MBOX_SIZE"
in your lwipopts.h, or ignore this parameter in your implementation
and use a default size.
If the mailbox has been created, ERR_OK should be returned. Returning any
other error will provide a hint what went wrong, but except for assertions,
no real error handling is implemented.
- void sys_mbox_free(sys_mbox_t *mbox)
Deallocates a mailbox. If there are messages still present in the
mailbox when the mailbox is deallocated, it is an indication of a
programming error in lwIP and the developer should be notified.
- void sys_mbox_post(sys_mbox_t *mbox, void *msg)
Posts the "msg" to the mailbox. This function have to block until
the "msg" is really posted.
- err_t sys_mbox_trypost(sys_mbox_t *mbox, void *msg)
Try to post the "msg" to the mailbox. Returns ERR_MEM if this one
is full, else, ERR_OK if the "msg" is posted.
- u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout)
Blocks the thread until a message arrives in the mailbox, but does
not block the thread longer than "timeout" milliseconds (similar to
the sys_arch_sem_wait() function). If "timeout" is 0, the thread should
be blocked until a message arrives. The "msg" argument is a result
parameter that is set by the function (i.e., by doing "*msg =
ptr"). The "msg" parameter maybe NULL to indicate that the message
should be dropped.
The return values are the same as for the sys_arch_sem_wait() function:
Number of milliseconds spent waiting or SYS_ARCH_TIMEOUT if there was a
timeout.
Note that a function with a similar name, sys_mbox_fetch(), is
implemented by lwIP.
- u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg)
This is similar to sys_arch_mbox_fetch, however if a message is not
present in the mailbox, it immediately returns with the code
SYS_MBOX_EMPTY. On success 0 is returned.
To allow for efficient implementations, this can be defined as a
function-like macro in sys_arch.h instead of a normal function. For
example, a naive implementation could be:
#define sys_arch_mbox_tryfetch(mbox,msg) \
sys_arch_mbox_fetch(mbox,msg,1)
although this would introduce unnecessary delays.
- int sys_mbox_valid(sys_mbox_t *mbox)
Returns 1 if the mailbox is valid, 0 if it is not valid.
When using pointers, a simple way is to check the pointer for != NULL.
When directly using OS structures, implementing this may be more complex.
This may also be a define, in which case the function is not prototyped.
- void sys_mbox_set_invalid(sys_mbox_t *mbox)
Invalidate a mailbox so that sys_mbox_valid() returns 0.
ATTENTION: This does NOT mean that the mailbox shall be deallocated:
sys_mbox_free() is always called before calling this function!
This may also be a define, in which case the function is not prototyped.
If threads are supported by the underlying operating system and if
such functionality is needed in lwIP, the following function will have
to be implemented as well:
- sys_thread_t sys_thread_new(char *name, void (* thread)(void *arg), void *arg, int stacksize, int prio)
Starts a new thread named "name" with priority "prio" that will begin its
execution in the function "thread()". The "arg" argument will be passed as an
argument to the thread() function. The stack size to used for this thread is
the "stacksize" parameter. The id of the new thread is returned. Both the id
and the priority are system dependent.
- sys_prot_t sys_arch_protect(void)
This optional function does a "fast" critical region protection and returns
the previous protection level. This function is only called during very short
critical regions. An embedded system which supports ISR-based drivers might
want to implement this function by disabling interrupts. Task-based systems
might want to implement this by using a mutex or disabling tasking. This
function should support recursive calls from the same task or interrupt. In
other words, sys_arch_protect() could be called while already protected. In
that case the return value indicates that it is already protected.
sys_arch_protect() is only required if your port is supporting an operating
system.
- void sys_arch_unprotect(sys_prot_t pval)
This optional function does a "fast" set of critical region protection to the
value specified by pval. See the documentation for sys_arch_protect() for
more information. This function is only required if your port is supporting
an operating system.
For some configurations, you also need:
- u32_t sys_now(void)
This optional function returns the current time in milliseconds (don't care
for wraparound, this is only used for time diffs).
Not implementing this function means you cannot use some modules (e.g. TCP
timestamps, internal timeouts for NO_SYS==1).
Note:
Be carefull with using mem_malloc() in sys_arch. When malloc() refers to
mem_malloc() you can run into a circular function call problem. In mem.c
mem_init() tries to allcate a semaphore using mem_malloc, which of course
can't be performed when sys_arch uses mem_malloc.
-------------------------------------------------------------------------------
Additional files required for the "OS support" emulation layer:
-------------------------------------------------------------------------------
cc.h - Architecture environment, some compiler specific, some
environment specific (probably should move env stuff
to sys_arch.h.)
Typedefs for the types used by lwip -
u8_t, s8_t, u16_t, s16_t, u32_t, s32_t, mem_ptr_t
Compiler hints for packing lwip's structures -
PACK_STRUCT_FIELD(x)
PACK_STRUCT_STRUCT
PACK_STRUCT_BEGIN
PACK_STRUCT_END
Platform specific diagnostic output -
LWIP_PLATFORM_DIAG(x) - non-fatal, print a message.
LWIP_PLATFORM_ASSERT(x) - fatal, print message and abandon execution.
Portability defines for printf formatters:
U16_F, S16_F, X16_F, U32_F, S32_F, X32_F, SZT_F
"lightweight" synchronization mechanisms -
SYS_ARCH_DECL_PROTECT(x) - declare a protection state variable.
SYS_ARCH_PROTECT(x) - enter protection mode.
SYS_ARCH_UNPROTECT(x) - leave protection mode.
If the compiler does not provide memset() this file must include a
definition of it, or include a file which defines it.
This file must either include a system-local <errno.h> which defines
the standard *nix error codes, or it should #define LWIP_PROVIDE_ERRNO
to make lwip/arch.h define the codes which are used throughout.
perf.h - Architecture specific performance measurement.
Measurement calls made throughout lwip, these can be defined to nothing.
PERF_START - start measuring something.
PERF_STOP(x) - stop measuring something, and record the result.
sys_arch.h - Tied to sys_arch.c
Arch dependent types for the following objects:
sys_sem_t, sys_mbox_t, sys_thread_t,
And, optionally:
sys_prot_t
Defines to set vars of sys_mbox_t and sys_sem_t to NULL.
SYS_MBOX_NULL NULL
SYS_SEM_NULL NULL
sys_arch interface for lwIP 0.6++
Author: Adam Dunkels
The operating system emulation layer provides a common interface
between the lwIP code and the underlying operating system kernel. The
general idea is that porting lwIP to new architectures requires only
small changes to a few header files and a new sys_arch
implementation. It is also possible to do a sys_arch implementation
that does not rely on any underlying operating system.
The sys_arch provides semaphores and mailboxes to lwIP. For the full
lwIP functionality, multiple threads support can be implemented in the
sys_arch, but this is not required for the basic lwIP
functionality. Previous versions of lwIP required the sys_arch to
implement timer scheduling as well but as of lwIP 0.5 this is
implemented in a higher layer.
In addition to the source file providing the functionality of sys_arch,
the OS emulation layer must provide several header files defining
macros used throughout lwip. The files required and the macros they
must define are listed below the sys_arch description.
Semaphores can be either counting or binary - lwIP works with both
kinds. Mailboxes are used for message passing and can be implemented
either as a queue which allows multiple messages to be posted to a
mailbox, or as a rendez-vous point where only one message can be
posted at a time. lwIP works with both kinds, but the former type will
be more efficient. A message in a mailbox is just a pointer, nothing
more.
Semaphores are represented by the type "sys_sem_t" which is typedef'd
in the sys_arch.h file. Mailboxes are equivalently represented by the
type "sys_mbox_t". lwIP does not place any restrictions on how
sys_sem_t or sys_mbox_t are represented internally.
Since lwIP 1.4.0, semaphore and mailbox functions are prototyped in a way that
allows both using pointers or actual OS structures to be used. This way, memory
required for such types can be either allocated in place (globally or on the
stack) or on the heap (allocated internally in the "*_new()" functions).
The following functions must be implemented by the sys_arch:
- void sys_init(void)
Is called to initialize the sys_arch layer.
- err_t sys_sem_new(sys_sem_t *sem, u8_t count)
Creates a new semaphore. The semaphore is allocated to the memory that 'sem'
points to (which can be both a pointer or the actual OS structure).
The "count" argument specifies the initial state of the semaphore (which is
either 0 or 1).
If the semaphore has been created, ERR_OK should be returned. Returning any
other error will provide a hint what went wrong, but except for assertions,
no real error handling is implemented.
- void sys_sem_free(sys_sem_t *sem)
Deallocates a semaphore.
- void sys_sem_signal(sys_sem_t *sem)
Signals a semaphore.
- u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout)
Blocks the thread while waiting for the semaphore to be
signaled. If the "timeout" argument is non-zero, the thread should
only be blocked for the specified time (measured in
milliseconds). If the "timeout" argument is zero, the thread should be
blocked until the semaphore is signalled.
If the timeout argument is non-zero, the return value is the number of
milliseconds spent waiting for the semaphore to be signaled. If the
semaphore wasn't signaled within the specified time, the return value is
SYS_ARCH_TIMEOUT. If the thread didn't have to wait for the semaphore
(i.e., it was already signaled), the function may return zero.
Notice that lwIP implements a function with a similar name,
sys_sem_wait(), that uses the sys_arch_sem_wait() function.
- int sys_sem_valid(sys_sem_t *sem)
Returns 1 if the semaphore is valid, 0 if it is not valid.
When using pointers, a simple way is to check the pointer for != NULL.
When directly using OS structures, implementing this may be more complex.
This may also be a define, in which case the function is not prototyped.
- void sys_sem_set_invalid(sys_sem_t *sem)
Invalidate a semaphore so that sys_sem_valid() returns 0.
ATTENTION: This does NOT mean that the semaphore shall be deallocated:
sys_sem_free() is always called before calling this function!
This may also be a define, in which case the function is not prototyped.
- err_t sys_mbox_new(sys_mbox_t *mbox, int size)
Creates an empty mailbox for maximum "size" elements. Elements stored
in mailboxes are pointers. You have to define macros "_MBOX_SIZE"
in your lwipopts.h, or ignore this parameter in your implementation
and use a default size.
If the mailbox has been created, ERR_OK should be returned. Returning any
other error will provide a hint what went wrong, but except for assertions,
no real error handling is implemented.
- void sys_mbox_free(sys_mbox_t *mbox)
Deallocates a mailbox. If there are messages still present in the
mailbox when the mailbox is deallocated, it is an indication of a
programming error in lwIP and the developer should be notified.
- void sys_mbox_post(sys_mbox_t *mbox, void *msg)
Posts the "msg" to the mailbox. This function have to block until
the "msg" is really posted.
- err_t sys_mbox_trypost(sys_mbox_t *mbox, void *msg)
Try to post the "msg" to the mailbox. Returns ERR_MEM if this one
is full, else, ERR_OK if the "msg" is posted.
- u32_t sys_arch_mbox_fetch(sys_mbox_t *mbox, void **msg, u32_t timeout)
Blocks the thread until a message arrives in the mailbox, but does
not block the thread longer than "timeout" milliseconds (similar to
the sys_arch_sem_wait() function). If "timeout" is 0, the thread should
be blocked until a message arrives. The "msg" argument is a result
parameter that is set by the function (i.e., by doing "*msg =
ptr"). The "msg" parameter maybe NULL to indicate that the message
should be dropped.
The return values are the same as for the sys_arch_sem_wait() function:
Number of milliseconds spent waiting or SYS_ARCH_TIMEOUT if there was a
timeout.
Note that a function with a similar name, sys_mbox_fetch(), is
implemented by lwIP.
- u32_t sys_arch_mbox_tryfetch(sys_mbox_t *mbox, void **msg)
This is similar to sys_arch_mbox_fetch, however if a message is not
present in the mailbox, it immediately returns with the code
SYS_MBOX_EMPTY. On success 0 is returned.
To allow for efficient implementations, this can be defined as a
function-like macro in sys_arch.h instead of a normal function. For
example, a naive implementation could be:
#define sys_arch_mbox_tryfetch(mbox,msg) \
sys_arch_mbox_fetch(mbox,msg,1)
although this would introduce unnecessary delays.
- int sys_mbox_valid(sys_mbox_t *mbox)
Returns 1 if the mailbox is valid, 0 if it is not valid.
When using pointers, a simple way is to check the pointer for != NULL.
When directly using OS structures, implementing this may be more complex.
This may also be a define, in which case the function is not prototyped.
- void sys_mbox_set_invalid(sys_mbox_t *mbox)
Invalidate a mailbox so that sys_mbox_valid() returns 0.
ATTENTION: This does NOT mean that the mailbox shall be deallocated:
sys_mbox_free() is always called before calling this function!
This may also be a define, in which case the function is not prototyped.
If threads are supported by the underlying operating system and if
such functionality is needed in lwIP, the following function will have
to be implemented as well:
- sys_thread_t sys_thread_new(char *name, void (* thread)(void *arg), void *arg, int stacksize, int prio)
Starts a new thread named "name" with priority "prio" that will begin its
execution in the function "thread()". The "arg" argument will be passed as an
argument to the thread() function. The stack size to used for this thread is
the "stacksize" parameter. The id of the new thread is returned. Both the id
and the priority are system dependent.
- sys_prot_t sys_arch_protect(void)
This optional function does a "fast" critical region protection and returns
the previous protection level. This function is only called during very short
critical regions. An embedded system which supports ISR-based drivers might
want to implement this function by disabling interrupts. Task-based systems
might want to implement this by using a mutex or disabling tasking. This
function should support recursive calls from the same task or interrupt. In
other words, sys_arch_protect() could be called while already protected. In
that case the return value indicates that it is already protected.
sys_arch_protect() is only required if your port is supporting an operating
system.
- void sys_arch_unprotect(sys_prot_t pval)
This optional function does a "fast" set of critical region protection to the
value specified by pval. See the documentation for sys_arch_protect() for
more information. This function is only required if your port is supporting
an operating system.
For some configurations, you also need:
- u32_t sys_now(void)
This optional function returns the current time in milliseconds (don't care
for wraparound, this is only used for time diffs).
Not implementing this function means you cannot use some modules (e.g. TCP
timestamps, internal timeouts for NO_SYS==1).
Note:
Be carefull with using mem_malloc() in sys_arch. When malloc() refers to
mem_malloc() you can run into a circular function call problem. In mem.c
mem_init() tries to allcate a semaphore using mem_malloc, which of course
can't be performed when sys_arch uses mem_malloc.
-------------------------------------------------------------------------------
Additional files required for the "OS support" emulation layer:
-------------------------------------------------------------------------------
cc.h - Architecture environment, some compiler specific, some
environment specific (probably should move env stuff
to sys_arch.h.)
Typedefs for the types used by lwip -
u8_t, s8_t, u16_t, s16_t, u32_t, s32_t, mem_ptr_t
Compiler hints for packing lwip's structures -
PACK_STRUCT_FIELD(x)
PACK_STRUCT_STRUCT
PACK_STRUCT_BEGIN
PACK_STRUCT_END
Platform specific diagnostic output -
LWIP_PLATFORM_DIAG(x) - non-fatal, print a message.
LWIP_PLATFORM_ASSERT(x) - fatal, print message and abandon execution.
Portability defines for printf formatters:
U16_F, S16_F, X16_F, U32_F, S32_F, X32_F, SZT_F
"lightweight" synchronization mechanisms -
SYS_ARCH_DECL_PROTECT(x) - declare a protection state variable.
SYS_ARCH_PROTECT(x) - enter protection mode.
SYS_ARCH_UNPROTECT(x) - leave protection mode.
If the compiler does not provide memset() this file must include a
definition of it, or include a file which defines it.
This file must either include a system-local <errno.h> which defines
the standard *nix error codes, or it should #define LWIP_PROVIDE_ERRNO
to make lwip/arch.h define the codes which are used throughout.
perf.h - Architecture specific performance measurement.
Measurement calls made throughout lwip, these can be defined to nothing.
PERF_START - start measuring something.
PERF_STOP(x) - stop measuring something, and record the result.
sys_arch.h - Tied to sys_arch.c
Arch dependent types for the following objects:
sys_sem_t, sys_mbox_t, sys_thread_t,
And, optionally:
sys_prot_t
Defines to set vars of sys_mbox_t and sys_sem_t to NULL.
SYS_MBOX_NULL NULL
SYS_SEM_NULL NULL