This commit cleans up the remaining instance of global variable
"index" shadowing caused by using local variables and function
parameters named "index"
These were introduced in the recent interface index API commits
Adjusts assert logic from 9c80a66253
to allow for a netif driver's init callback to manually override
the number. When the init function is taking care of the unique
assignment, the assert simply checks that a valid number was provided
This commit adds an LWIP_ASSERT to detect when netif_num overflows and
we no longer have unique numbers per netif. Unique netif numbers are
needed to support interface indexes (task #14314)
The only cases where this could occur are with a deployment that attempts
to use the maximum 256 netifs at the same time or where netifs are being
constantly adding and removed. Neither of these use cases fit the
lightweight goals of LwIP
See discussion in task #14314 for more details
For applications that use NETIF_STATUS_CALLBACK to help keep track of
extra per-address shadow state of IPv6 addresses, even in the light of
autogenerated addresses (which may "spontaneously" appear/disappear),
state transitions between tentative, duplicated, and invalid are
important as well. Therefore, invoke the status callback for all such
state transitions. Continue to filter out state changes between
various levels of progress of the tentative state, though.
In summary, this patch aims to resolve bugs #47923 and #48162, by
decoupling address autoconfiguration from the on-link prefix list,
since those are not related. Important necessary changes are needed
to meet this goal, ultimately bringing the lwIP ND6 implementation
closer to compliance with RFC 4862. The main changes are:
1. support for address lifetimes, and,
2. addition of a new DUPLICATED address state.
The decoupling implies that the prefix list can no longer be used to
maintain state for address autoconfiguration. Most importantly, the
lifetime of each address, which was previously derived from the
prefix slot's lifetime, must now be associated with the address
itself. This patch implements address lifetime tracking, maintaining
both a valid and a preferred lifetime for each address, along with
the corresponding address state changes (e.g., between PREFERRED and
DEPRECATED), all as required by RFC 4862.
The support for address lifetimes can be enabled with a new
LWIP_IPV6_ADDRESS_LIFETIMES setting in lwipopts.h. It is required for
autoconfiguration and enabled by default if autoconfiguration is
enabled as well, but it may also be enabled separately, so as to allow
application-controlled lifetime management (e.g., if autoconfiguration
is implemented in a separate application). A special valid-lifetime of
zero is used to denote a static address--that is, an address that was
configured manually, that does not have lifetimes, and that should be
left alone by the autoconfiguration functionality. Addresses assigned
without setting a lifetime are deemed static, thus preserving
compatibility with existing lwIP-based applications in this respect.
Similarly, the decoupling implies that the prefix list can no longer
be used to remember cases of address duplication. Previously, the
detection of a duplicated address would simply result in removal of
the address altogether. Instead, this patch introduces a new state
"DUPLICATED", indicating that the address, while technically still
present, has been found to conflict with other node addresses, and no
attempt should be made to produce an autoconfiguration address for
that prefix.
Manually added addresses, including the link-local address, once set
to DUPLICATED, will remain in that state until manual intervention.
Autoconfigured DUPLICATED addresses will expire according to their
valid-lifetime, essentially preserving the current behavior but
without the use of the prefix list. As a first attempt to approach
compliance with RFC 4862 Sec. 5.4.5, if the link-local address is
detected to be duplicated, all derived addresses are marked duplicated
as well, and no new addresses will be autoconfigured. More work is to
be done for full compliance with that section, however.
Together, those two main changes indeed do fully decouple address
autoconfiguration from the on-link prefix list. Changes to the latter
thus no longer affect the former, resolving bug #47923. Moreover, as a
result, autoconfiguration can, and does, now also take place on
advertised prefixes that do not have the on-link flag set, resolving
bug #48162. The routing changes mentioned in the discussion of that
bug are left to a separate patch, though.
If MLD support is enabled, each locally assigned IPv6 address in the
appropriate state must be a member of the solicited-node multicast
group corresponding to that address. Ensure that this is always the
case by (re-)deciding on the membership upon every address state
change. By doing so, this patch enforces that user-initiated state
changes to addresses (e.g., deletion) never cause a desynchronization
with the corresponding solicited-node multicast group membership,
thereby making such user-initiated state changes simpler and safer.
All the reset part of the code accessing netif->loop_first has lock protection,
the only missing part is "while (netif->loop_first != NULL)".
Fix it by adding lock protect around the while loop.
Also convert the code to use while{} loop instead of do .. while{} loop,
then we can avoid NULL test for in pointer in each loop and reduce a level of indent.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
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>
Reasoning:
- Makes code in single-netif case perform better and smaller
- IGMP / MLD6 code is a little bit easier to read and understand
- Easier to get multicast groups per netif when implementing drivers
Downside: In multi-netif mode, there are two more pointers on each netif, even if IGMP/MLD6 is not used on it. But these systems should not be so memory-constrained that this will matter.
