ppp_sighup() hard change the PPP FSM phase, it ends up with a FSM
mismatch if PPP is currently connecting or disconnecting.
Only do "sighup" on the stable running phase, fallback to the close
method. Handle special DEAD and HOLDOFF states as well.
We can have an IPv6 only PPP interface, checking if6_up instead of if_up fixes
IPv6 only setup.
ppp_netif_output() which were only used for common code between
ppp_netif_output_ip4() and ppp_netif_output_ip6() is not necessary
anymore, removed, reducing call stack by one.
This is now totally useless, it was used for the PPP core code but it is not
used anymore, remove then the user ability to set the PPP error code through
PPPCTLS_ERRCODE.
Removed useless calls to ppp_ioctl(pcb, PPPCTLS_ERRCODE, …), we now assign
pcb->err_code directly instead. ppp_ioctl() is not linked anymore if user
application don't use it.
lwip/src/netif/ppp/polarssl/md4.c:43:20: warning: "LWIP_INCLUDED_POLARSSL_MD4" is not defined [-Wundef]
lwip/src/netif/ppp/polarssl/sha1.c:42:20: warning: "LWIP_INCLUDED_POLARSSL_SHA1" is not defined [-Wundef]
lwip/src/netif/ppp/polarssl/des.c:43:20: warning: "LWIP_INCLUDED_POLARSSL_DES" is not defined [-Wundef]
Added macro PPP_AUTH_SUPPORT, if none of auth protocols are enabled
(PAP, CHAP, EAP) we reduce PPP memory usage by compiling out all
struct fields and source code used for authentication.
VJ is only supported for PPPoS, RFCs does not say VJ is forbidden on
PPPoE or PPPoL2TP (looks like it is strongly discouraged though, due
to checksum issues when using VJ).
We only need to keep track of existing PPPoS interfaces if PPPoS
is not the only enabled protocol.
PPP CORE does not have callbacks pointers for all PPPoS callbacks
which should actually be required for PPPoS (VJ config, asyncmap, ...),
there is too much callbacks to create and PPPoS must be kept light,
especially for users who are only using PPPoS.
But there is a drawback, PPP CORE does not know which
lower protocols it is talking to thanks to the abstraction,
therefore if PPPoS is enabled as well as PPPoE or PPPoL2TP there
might be situation where PPP CORE calls pppos_ config functions
on interfaces which are NOT PPPoS one. This is very unlikely to
happen because protocols not supported by PPPoE or PPPoL2TP are
disabled at LCP/IPCP negotiation but we are better safe than sorry.
So we check if passed PPP pointer to PPPoS configuration functions
is a PPPoS interface by checking against a linked list of existing
PPPoS interfaces.
