PPP, PPPoE: fix trivial build error

lwip/src/netif/ppp/pppoe.c: In function ‘pppoe_send_padt’:
lwip/src/netif/ppp/pppoe.c:1048:108: error: ‘sc’ undeclared (first use in this function)

sc is not passed to ‘pppoe_send_padt’ function because it might be
called to terminate unknown sessions.

Fixes: d4047ea1d185 ("Try to fix issues reported by coverity")
Signed-off-by: Sylvain Rochet <gradator@gradator.net>

Try to fix issues reported by coverity

Add LWIP_ASSERT_CORE_LOCKED() to ppp (see task #14780)

Signed-off-by: goldsimon <goldsimon@gmx.de>

Even more pbuf_header -> pbuf_add/remove_header replacements (also in strings)

More pbuf_header -> pbuf_add/remove_header replacements

PPP: remove ppp_singlebuf

We don't have to keep a helper function just for the sake of a PBUF_RAW
constant. Inline ppp_singlebuf function.

Signed-off-by: Sylvain Rochet <gradator@gradator.net>

backport of "variable assigned but not used" warnings from STM (why don't people report such things?)

PPP: remove unused and confusing return values other than ERR_OK for ppp_connect and ppp_listen

User should not use ppp_connect or ppp_listen return value to retry
later, it must wait for the callback to be called. This is primarily
done this way to have a consistent behavior with and without the
holdoff feature.

Remove returned error value from PPP link level API connect and listen
callbacks because we are not using them anymore, then make ppp_connect
or ppp_listen to always return ERR_OK, thus we are not breaking the PPP
user API.

We don't need the return code here, all PPP link level drivers can't
fail at all (e.g. PPPoS) or retry if necessary (PPPoE and PPPoL2TP).

Cleanup hton*/ntoh* function handling and platform abstraction
Let lwip use functions/macros prefixed by lwip_ internally to avoid naming clashes with external #includes.
Remove over-complicated #define handling in def.h
Make functions easier to override in cc.h. The following is sufficient now (no more LWIP_PLATFORM_BYTESWAP):
#define lwip_htons(x) <your_htons>
#define lwip_htonl(x) <your_htonl>

PPP, PPPoE: Include netif/ethernet.h to fix build error

Fix below build errors:
In file included from ../../../../../lwip/src/include/netif/ppp/ppp_opts.h:31:0,
from ../../../../../lwip/src/netif/ppp/pppoe.c:71:
../../../../../lwip/src/netif/ppp/pppoe.c: In function ‘pppoe_timeout’:
../../../../../lwip/src/netif/ppp/pppoe.c:861:30: error: ‘ethbroadcast’ undeclared (first use in this function)
MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
^
../../../../../lwip/src/include/lwip/opt.h:137:52: note: in definition of macro ‘MEMCPY’
#define MEMCPY(dst,src,len) memcpy(dst,src,len)
^
../../../../../lwip/src/netif/ppp/pppoe.c:861:30: note: each undeclared identifier is reported only once for each function it appears in
MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
^
../../../../../lwip/src/include/lwip/opt.h:137:52: note: in definition of macro ‘MEMCPY’
#define MEMCPY(dst,src,len) memcpy(dst,src,len)
^
../../../../../lwip/src/netif/ppp/pppoe.c: In function ‘pppoe_connect’:
../../../../../lwip/src/netif/ppp/pppoe.c:899:24: error: ‘ethbroadcast’ undeclared (first use in this function)
MEMCPY(&sc->sc_dest, ethbroadcast.addr, sizeof(sc->sc_dest));
^
../../../../../lwip/src/include/lwip/opt.h:137:52: note: in definition of macro ‘MEMCPY’
#define MEMCPY(dst,src,len) memcpy(dst,src,len)
^
../../Common.mk:94: recipe for target 'pppoe.o' failed
make: *** [pppoe.o] Error 1

Fixes: 8eb9db18a2d9 ("Reduce usage of netif/ethernet.h header, mostly lwip/prot/ethernet.h is sufficient")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: goldsimon <goldsimon@gmx.de>

Fix a few incorrect uses of err_t. Found by converting lwip error codes to an enum, but I'm not sure wether I want to commit the actual enum conversion.

PPP, PPPoE: remove useless checks

pppoe_softc_list is always not null when pppoe_find_softc_by_session is
called, furthermore pppoe_softc_list being null here does not hurt.

session is still checked whatsoever in pppoe_find_softc_by_session,
prechecking the session value for a value which can't really happen
except for forged frames does not add any value.

PPP, PPPoE: cleanup connection state reset

Instead of relying on cleanup at the end of session, cleanup as much as
possible in the connect callback. It removes duplicated code and make
everything simpler to read.

While we are at it, remove useless initialization code from create
and connect functions.

PPP, PPPoE: add support for disconnecting in link initiation state in disconnect callback

Disconnect callback does not currently support a disconnect event while
initiation is in progress. Retry timer is not stopped and PADT frame is
sent whatever the current state is. PADT frame can only be sent if we
received a PADS frame, otherwise sc_session is 0 and sending a PADT
frame is meaningless.

Fix both issues to allow calling the disconnect callback whatever the
PPPoE state is.

PPP: remove useless ppp_link_start function

This function only set PPP to initialize phase, and it is only called at
the very beginning of functions where it is called. It means we could
as well set the initialize phase before calling those functions in the
PPP core.

PPP, PPPoE: remove useless PPPoE state conditions

sc->sc_ethif can't be NULL, it is set definitively in pppoe_create.

PPPoE can't by anything else than PADI sent in pppoe_send_padi, it
is only called when this is true.

PPPoE state can't be anything else than initial state in
pppoe_connect, this function is called from PPP core only when PPP
is in the dead phase, if PPP is in the dead phase it means the link
protocol is dead as well.

PPPoE can't be anything else than data phase in pppoe_disconnect
this function is only called by PPP core only when PPP session is up,
if PPP session is UP it means the link protocol is UP as well.

PPPoE can't by anything else than PADR sent in pppoe_send_padr, it
is only called when this is true.

PPPoE can't by anything else than PADO sent in pppoe_send_pado, it
is only called when this is true.

PPPoE can't by anything else than PADO sent in pppoe_send_pads, it
is only called when this is true.

PPPoE can't be anything else than session phase in pppoe_xmit,
function is only called by pppoe_write and pppoe_netif_output
which are both called by PPP core only when PPP session is up, if
PPP session is UP it means the link protocol is UP as well.

Fix bug #48436: Naming clash for timers.c (with FreeRTOS)
Rename timers.* to timeouts.*

PPP, PPPoE, PPPoL2TP: enforce disabling of silent and passive modes

PPP is just the upper protocol for PPPoE and PPPoL2TP, meaning it is only
started once "E" or L2TP is established. Therefore waiting indefinitely
for LCP packets on the PPP side does not make sense at all, if the lower
level protocol is UP, PPP *MUST* comes up as well or we should restart from
the beginning.

PPP, PPPoE: fix potential out-of-bound if AC cookie is too long

Found by coverity.

Introduced by c0e7d54e37 "Removed 2 mem_mallocs: error string can be a
global variable, include memory for sc_ac_cookie in struct pppoe_softc;
commented out unused code (sc_service_name/sc_concentrator_name)".

Fixes it by bailing out if received AC cookie is to big for us, this
can't really happen anyway.

PPP, rename ppp_clear function to ppp_link_start

This function does not clear anything anymore. What it is now is an
optional way to notify PPP that link layer is started, changing the
PPP state from "dead" to "initialize". Rename it accordingly to what
the function really is.

task #13907: PPP cleanups: Move PPP mempools out of lwIP core to PPP code

Work on task #13907 PPP cleanups: Move PPP options from opt.h to dedicated ppp_opts.h file

Rename snmp_mib2.h to snmp.h so source compatibility for user netif implementations is preserved

PPP, merged ppp_link_set_callbacks() into ppp_new()

PPP, reorder initialisation of low level protocols to call ppp_link_set_callbacks() just after PPP control block allocation

PPP, remove now unused ioctl callback from link_callbacks structure

Separate mib2 counter/table callbacks from snmp agent. This both cleans up the code and should allow integration of a 3rd party agent/mib2.

PPP, added missing cast on pbuf_header()

PPP, VJ, CCP: rework to fix protocol order

We need to do VJ compression before CCP/MPPE compression and VJ
decompression after CCP/MPPE decompression. This leads to a massive
rewrite of how we currently handled VJ only in the PPPoS lower protocol
handler.

Moved VJ structures from pppos to ppp_pcb because we need them back in
PPP core. This is a bit unfortunate because that's not necessary for
PPPoE or PPPoL2TP, but, hey!. Fixed CCP+MPPE+VJ order.

PPP, PPPoE, removed unnecessary single pbuf

Removed ppp_singlebuf() in pppoe_data_input(), chained pbuf are
perfectly acceptable for IP data and we are currently supporting them
perfectly for PPPoS. The PPP stack itself (LCP, IPCP et al.) does not
support chained pbuf and is already calling ppp_singlebuf() just before
passing packet to the protocol handler.

PPP, cleared warnings if PPP_DEBUG is off

PPP, fixed warnings if LWIP_SNMP is disabled

PPP, PPPoE, removed redundant size check

PPP, ppp->last_xmit is only used in PPPoS, moved to PPPoS

Only PPPoS need to keep track of last transmitted packet for HDLC flag,
removed from PPPoE and PPPoL2TP and moved to PPPoS.

PPP, PPPoE and PPPoL2TP, removed ppp->pcomp usage

We refuse protocol compression in both PPPoE and PPPoL2TP, therefore
ppp->pcomp can't be true, removed.

PPP, IPCP, fully removed VJ support from IPCP if VJ_SUPPORT is disabled

PPP, PPPoE, removed devname variable from pppoe_disc_input()

Only used for debug, reworked in a more clever way. It was actually broken
by design: setting an interface integer into a string without formatting
was quite a dumb idea.

PPP, PPPoE, improve reliability if we receive a PADT

Don't disconnect when we receive a PADT, we let the LCP Echo/Reply find
the fact that PPP session is down. Asking the PPP stack to end the
session require strict checking about the PPP phase to prevent endless
disconnection loops.

Luckily it previously does nothing because PADT frames are rarely sent
with a hunique tag and we only set the sc pointer if we receive a
hunique tag.

PPP, PPPoE, removed global static buffer only used for debug

pppoe_error_tmp[] was only used in one function and only for debug purposes,
moved to stack.

PPP, SERVER: added PPPoS server support

New function: ppp_listen(), listen for an incoming PPP connection.

PPP, remove VJ callback from link_callbacks if VJ support is not enabled

PPP, IPv4 support is now optional

New compile time option: PPP_IPV4_SUPPORT

PPP IPv4 support can now be compiled out.

PPP, PPPoE, removed PPPERR_ usage

Low level protocol callbacks are using err_t returns type,
don't use PPPERR_ on them.

PPP, PPPoS, moved VJ protocol handler to PPPoS

New callback, netif input, allow low level drivers to extend
ppp_input call, moved PPPoS VJ support to pppos.c.

PPP, PPPoS, added sub-ioctl commands

Allow low level drivers to extend ioctl call, moved PPPoS ioctl
commands to pppos.c.

PPP, uniformised callbacks naming

PPP, CORE, new callbacks, send_config, recv_config, vj_config

Removed some calls from PPP core to PPPoS low level protocols,
the const struct allows us to have more and more callbacks
without using more RAM.

PPP, CORE, now using const callbacks struct from lower level protocols

Saving some RAM by using callbacks struct in rodata for required
callbacks called by PPP core to PPP low level protocols.

PPP, lower protocols, chained returns from local functions to callback caller

PPPoS,PPPoE,PPPoL2TP functions using non-void returns are now propagated
to callback caller (PPP core).

PPP, CORE, prepared for lower protocols callbacks returning state

Until now, callbacks used void return, preparing callbacks to return
PPPERR_ status.

PPP, all protocols, uniformised naming

Uniformised fonction naming between and inside PPPoS, PPPoE, PPPoL2TP.

PPP, PPPoE, improved removal from linked list

Replaced naive link list removal code to a more clever one.

PPP, PPPoS, moved VJ from PPP core to PPPoS

VJ is only available for PPPoS, moved VJ from PPP CORE to PPPoS.

PPP, generalized callbacks calls from PPP core, removed all PPPoE and PPPoL2TP references

Almost there, removed all PPPoE and PPPoL2TP references from PPP core,
using the generic callbacks interface everywhere.

PPP, moved low level protocol connect init to low level protocol files

Low level protocol init machine state does not belong to PPP core,
moved those init to respective low level protocol files.

PPP, removed low level create functions from PPP core

ppp_over_ethernet_create() moved from ppp.c to pppoe.c
ppp_over_l2tp_create() moved from ppp.c to pppol2tp.c

PPP, moved ppp_write and ppp_netif_output low level protocols functions to respective low level protocol files

Moved ppp_write_over_ethernet() and ppp_netif_output_over_ethernet() to pppoe.c
Moved ppp_write_over_l2tp() and ppp_netif_output_over_l2tp() to pppol2tp.c

PPP, prepare new callbacks for low level protocols

New callbacks: write and netif_output

PPP: prepared callbacks from PPP core to low level protocols

New PPP callback from PPP core to low level protocols, first
step about removing named calls to low level protocols from PPP core.

PPP: removed PPPoE and PPPoL2TP callback status notifier

Added necessary PPP core functions for PPPoE and PPPoL2TP status
notificaton (ppp_link_failed and ppp_link_end), removed callback,
low level protocol are now calling PPP core "link" functions.

PPP: moved ppp_new() to low level protocol init for PPPoE and PPPoL2TP

First step of a rework of how low level protocols are using the
PPP core. Low level protocols are now going to use the core instead
of core using the low level protocols.

Final goal: separate PPP core code from low level protocols.

PPP, fixed some compiler warnings

Using -Wall -pedantic -Wparentheses -Wsequence-point
-Wswitch-default -Wextra -Wundef -Wshadow -Wpointer-arith
-Wbad-function-cast -Wc++-compat -Wwrite-strings -Wold-style-definition
-Wmissing-prototypes -Wredundant-decls -Wnested-externs -Wno-address

fixed bug #43235, cleared compiler warnings when using gcc with -Wextra option

PPP, PPPoE, fixed bug #42138, pppoe_destroy() called with wrong pointer, PPPoE control block was never freed

PPP, adding const pragma to FSM callbacks, saving about 350 bytes in .data segment

Moved PPP headers into include/netif/ppp/, fixing bug #37040.