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.
This patch adds a new RAW_FLAGS_HDRINCL flag to the raw core
implementation. When this flag is set on a RAW PCB, the raw send
routines expect the caller to supply an IP header for the given
packet, and will use that IP header instead of prepending one to
the packet themselves.
This feature allows the IP_HDRINCL socket option to be implemented
in higher layers with no further effort. Even thoguh that option is
traditionally supported for IPv4 sockets only (e.g., see RFC 3542
Sec. 3), the RAW_FLAGS_HDRINCL flag supports both IPv4 and IPv6, as
much of the lower-level infrastructure was already in place anyway.
Similar to the core UDP API, the new function may be used to implement
IPV6_PKTINFO (RFC 3542 Sec. 4), for example. This patch makes no
further functional changes; it merely moves code around a bit.
The support for connecting raw sockets is extended to match the
support for UDP sockets, while keeping the current API unchanged:
- for connected sockets, filter incoming packets on source address;
- use a flag to indicate whether a socket is connected, at no extra
memory cost; the application may check this flag if needed;
- added raw_disconnect(), which so far existed in documentation only.
The caller of tcp_listen_with_backlog_and_err() usually check if the return
pcb is NULL before checking the err reason. I think the commit adding
tcp_listen_with_backlog_and_err() accidently change the behavior, Fix it.
Fixes: 98fc82fa71 ("added function tcp_listen_with_backlog_and_err() to get the error reason when listening fails")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
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.
The code in the for loop checks tmp_group->next == group, so current code
actually checks from the 3rd entry in the linked groups list. Fix it.
Fixes: 5c1dd6a4c6 ("Optimization in igmp_remove_group() pointed out by Axel Lin")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
This commit adds support for responding to a zero-window probe when
the refused_data pointer is set
A zero-window probe is a data segment received when rcv_ann_wnd
is 0. This corrects a standards violation where LwIP would not
respond to a zero-window probe with its current ACK value (RCV.NXT)
when it has refused data, thus leading to the probing TCP closing
out the connection
lwIP produces a TCP Initial Sequence Number (ISN) for each new TCP
connection. The current algorithm is simple and predictable however.
The result is that lwIP TCP connections may be the target of TCP
spoofing attacks. The problem of such attacks is well known, and a
recommended ISN generation algorithm is standardized in RFC 6528.
This algorithm requires a high-resolution timer and cryptographic
hashing function, though. The implementation (or best-effort
approximation) of both of these aspects is well beyond the scope of
lwIP itself.
For that reason, this patch adds LWIP_HOOK_TCP_ISN, a hook that
allows each platform to implement its own ISN generation using
locally available means. The hook provides full flexibility, in
that the hook may generate anything from a simple random number
(by being set to LWIP_RAND()) to a full RFC 6528 implementation.
Implementation note:
Users of the hook would typically declare the function prototype of
the hook function in arch/cc.h, as this is the last place where such
prototypes can be supplied. However, at that point, the ip_addr_t
type has not yet been defined. For that reason, this patch removes
the leading underscore from "struct _ip_addr", so that a prototype
of the hook function can use "struct ip_addr" instead of "ip_addr_t".
Signed-off-by: sg <goldsimon@gmx.de>
Fix below build error when LWIP_ND6_RDNSS_MAX_DNS_SERVERS == 0
../../../../lwip/src/core/ipv6/nd6.c: In function ‘nd6_input’:
../../../../lwip/src/core/ipv6/nd6.c:400:10: error: unused variable ‘rdnss_server_idx’ [-Werror=unused-variable]
u8_t rdnss_server_idx = 0;
^~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
../Common.mk:93: recipe for target 'nd6.o' failed
make: *** [nd6.o] Error 1
Fixes: 6b1950ec24 ("nd6: add support for RDNSS option (as per RFC 6106)")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Previously, ethip6 and lowpan6 each had their own copy of code that
used internal nd6 data structures to decide whether to send a packet
on the local link right away, or queue it while nd6 performed local
address resolution. This patch moves that code into nd6, thereby
eliminating all remaining cases of external access to internal nd6
data structures, as well as the need to expose two specific nd6
functions.
As a side effect, the patch effectively fixes two bugs in the lowpan6
code that were already fixed in the ethip6 code.
This patch rearranges the code division between nd6.c and ip6.c such
that the latter does not need to access ND6-internal data structures
(specifically, "default_router_list") directly anymore.
The new function, while currently not used internally, allows external
code to clear the ND destination cache in the case that it may have
become inconsistent with the current situation, for example as the
result of a change of locally assigned addresses, or a change in
routing tables implemented through the LWIP_HOOK_ND6_GET_GW hook.
On failure, nd6_get_next_hop_entry() returns an ERR_ type negative
error code. ethip6_output() erroneously assumed that that error would
always be ERR_MEM, even though it may also be ERR_RTE in practice.
With this patch, ethip6_output() simply forwards the returned error.
This commit increments the ip.drop statistic when an IP packet is
dropped due to no matching netif found and forwarding is disabled
This adds parity to the other places where mib2.ipinaddrerrors and
mib2.ipindiscards are incremented which also increment ip.drop
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>
While TCP_OVERSIZE works only when tcp_write() is used with
TCP_WRITE_FLAG_COPY, this new code achieves
similar benefits for the use case that the caller manages their own
send buffers and passes successive chunks of those to tcp_write()
without TCP_WRITE_FLAG_COPY.
In particular, if a buffer is passed to
tcp_write() that is adjacent in memory to the previously passed
buffer, it will be combined into the previous ROM pbuf reference
whenever possible, thus extending that ROM pbuf rather than allocating
a new ROM pbuf.
For the aforementioned use case, the advantages of this code are
twofold:
1) fewer ROM pbufs need to be allocated to send the same data, and,
2) the MAC layer gets outgoing TCP packets with shorter pbuf chains.
Original patch by Ambroz Bizjak <ambrop7@gmail.com>
Edited by David van Moolenbroek <david@minix3.org>
Signed-off-by: goldsimon <goldsimon@gmx.de>
Change lwIP UDP API to match socket behavior. Multicast traffic is now only received on a UDP PCB (and therefore on a UDP socket/netconn) when the PCB is bound to IP_ADDR_ANY.
Generally speaking, packets with a loopback destination address -
127.0.0.1 for IPv4 and ::1 for IPv6 - should not be accepted on
non-loopback interfaces. For IPv4, this is implied by RFC 1122
Sec. 3.2.1.3. For IPv6, it is mandated by RFC 4291 Sec. 2.5.3.
Failure to perform this filtering may have security implications, as
applications that bind sockets to loopback addresses may not expect
that nodes on the local external network be able to produce traffic
that will arrive at such sockets.
With this patch, lwIP drops packets that are sent to a loopback
address but do not originate from the interface that has the loopback
address assigned to it. This approach works regardless of whether it
is lwIP or the system using it that implements a loopback netif. The
only exception that must be made is for configurations that enable
netif packet loopback but disable the lwIP loopback netif: in that
case, loopback packets are routed across non-loopback netifs and would
thus be lost by the new filter as well.
For IPv6, loopback-destined packets are also no longer forwarded; the
IPv4 forwarding code already had a check for that.
As a small performance improvement, the IPv6 link-local/loopback
address check is now performed only once per packet rather than
repeatedly for every candidate netif.
In general, netif_default may be NULL, and various places in the code
already check for this case before attempting to dereference the
netif_default pointer. Some places do not perform this check though,
and may cause null pointer dereferences if netif_default is not set.
This patch adds NULL checks to those places as well.
bind() may change IP type when previous type is IPADDR_TYPE_ANY
connect() IP type must exactly match bind IP type
Use correct IPADDRx_ANY type when calling ip_route()
This commit returns LwIP to previous behavior where if the next unsent
segment can't be sent due to the current send window, we start the
persist timer. This is done to engage window probing in the case that
the subsequent window update from the receiver is dropped, thus
preventing connection deadlock
This commit refines the previous logic to only target the following case:
1) Next unsent segment doesn't fit within the send window (not
congestion) and there is some room in the window
2) Unacked queue is empty (otherwise data is inflight and the RTO timer
will take care of any dropped window updates)
See commit d8f090a759 (which removed this
behavior) to reference the old logic. The old logic falsely started the
persit timer when the RTO timer was already running.
This commit cleans up a duplicate #if check for LWIP_WND_SCALE in init.c
which was already under #if LWIP_WND_SCALE
This commit also improves documentation for TCP_WND in the window scaling
case to communicate TCP_WND is always the calculated (scaled) window value,
not the value reported in the TCP header
Our developers were confused by having to set both the window and scaling
factor and only after studying the usage of TCP_WND throughout the code, was
it determined to be the calculated (scaled) window
p needs to point to LWIP_MEM_ALIGN(memp_pools[i]->base) otherwise it will cause
assertion in overflow checking.
Fixes: c838e1ed5b ("Implement possibility to declare private memory pools")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
When memp_free_pool was split out from memp_free (c838e1ed5b),
the check for freeing the null pointer was lost.
This resulted in the null value being put back in the list of free
objects, causing all subsequent allocations of that type to fail.
The mld_group structure no longer has a 'netif' field, as such
structures are now linked from the corresponding netif structure.
For conditional checksumming, use the calling function's netif
reference instead.
This comment is incorrect since commit 7d0dab9d7d
"partly fixed bug #25882: TCP hangs on MSS > pcb->snd_wnd
(by not creating segments bigger than half the window)".
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>
TCP's snd_nxt represents the next sequence number after sent data, and
as such does not cover any unsent data queued on the connection. The
current implementation does not take the latter point into account
when processing FIN acknowledgments, mistakenly assuming that an
outgoing FIN is ACK'ed when the acknowledgment covers up to snd_nxt
while there is still unsent data. This patch adds a check for unsent
data to correct this, effectively preventing that TCP connections are
closed prematurely.
It is possible that the byte sent as a zero window probe is accepted
and acknowledged by the receiver side without the window being opened.
In that case, the stream has effectively advanced by one byte, and
since lwIP did not take this into account on the sender side, the
result was a desynchronization between the sender and the receiver.
That situation could occur even on a lwIP loopback device, after
filling up the receiver side's receive buffer, and resulted in an ACK
storm. This patch corrects the problem by advancing the sender's next
sequence number by one as needed when sending a zero window probe.
delay_time and stale_time are ticks now.
reachable_time and invalidation_timer are untouched since they may originate from telegram values -> not converting them to ticks avoids an integer division
commit 8c52afb6ca ("igmp: Optimize code by always skipping the first entry in the linked groups list - it is always the "allsystems" entry")
accidently changes the code logic. it should check groupref rather than group.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
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.
When leaving a multicast group, remove the group from the list
before invoking the MAC filter callback. This avoids the need
for the callee to skip over the group that is about to be deleted.
This commit adds support to the sanity checks in init.c to ensure that
PBUF_POOL is in use
In ports with drivers/netifs that use PBUF_REF for the RX pathway, there
is no need for the PBUF_POOL memory pool. This allows the port to define
PBUF_POOL_SIZE to 0
commit 44e1a2d8e2 accidently includes below changes in tcp_listen_with_backlog
- tcp_backlog_set(lpcb, backlog);
+ lpcb->backlog = backlog;
Thus pass 0 to the backlog parameter of netconn_listen_with_backlog() fails.
Fixes: 44e1a2d8e2 ("define tcp_backlog_set() as dummy-define when backlog feature is disable")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: goldsimon <goldsimon@gmx.de>
MEMP_SANITY_REGION_BEFORE and MEMP_SANITY_REGION_AFTER can be overridden in
lwipopts.h, if one of it is set to 0 we got build error due to unused variable.
Fix unused variable build error when MEMP_OVERFLOW_CHECK >= 1 &&
(MEMP_SANITY_REGION_BEFORE == 0 || MEMP_SANITY_REGION_AFTER == 0).
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: goldsimon <goldsimon@gmx.de>
There is only one caller using memp_overflow_init(), and at that context
calling memp_overflow_init_element() actually simplifes the code.
Thus remove memp_overflow_init() function.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: goldsimon <goldsimon@gmx.de>
Use LWIP_MEM_ALIGN() in memp_overflow_init() to get alignment address for memp.
This fixes assertion in memp_overflow_check_element_overflow when
MEMP_OVERFLOW_CHECK is set.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Fix below build error.
../../../../../lwip/src/core/memp.c: In function ‘memp_free’:
../../../../../lwip/src/core/memp.c:490:31: error: request for member ‘tab’ in something not a structure or union
old_first = memp_pools[type].tab;
^
../../Common.mk:94: recipe for target 'memp.o' failed
make: *** [memp.o] Error 1
Fixes: de9054cb7a ("memp: cleaned up MEMP_MEM_MALLOC")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
In the BSD socket API world, IP_HDRINCL is a socket option for "raw"
sockets that indicates whether sent packets already include an IP
header. Within lwIP, "IP_HDRINCL" is redefined as a special value
that indicates to lwIP-internal functions that an IP header is already
included. While somewhat related, the two meanings are different and,
on platforms that define the IP_HDRINCL socket option, this results in
a conflict. This patch renames the lwIP one to "LWIP_IP_HDRINCL",
thus resolving the conflict.
- support memp stats when MEMP_MEM_MALLOC==1 (bug #48442);
- hide MEMP_MEM_MALLOC in memp.c instead of messing up the header file;
- make MEMP_OVERFLOW_CHECK work when MEMP_MEM_MALLOC==1
Fixes bug #48300 (Private mempools allocate foreign memory), bug #48354 (Portable alignment defines/include required for static allocation) and bug #47092 (Tag memory buffers like memp_memory_xxx and ram_heap with a macro so that attributes can be attached to their definitions)
Signed-off-by: Simon Goldschmidt <goldsimon@gmx.de>
If lwIP encounters a half-open connection (e.g. due to a restarted
application reusing the same port numbers) it will correctly send a
RST but will not resend the SYN until one retransmission timeout later
(approximately three seconds). This can increase the time taken by
lpxelinux.0 to fetch its configuration file from a few milliseconds to
around 30 seconds.
Fix by immediately retransmitting the SYN whenever a half-open
connection is detected.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: goldsimon <goldsimon@gmx.de>
lwip/src/core/init.c:256:32: error: "LWIP_COMPAT_MUTEX" is not defined [-Werror=undef]
#if LWIP_TCPIP_CORE_LOCKING && LWIP_COMPAT_MUTEX && !defined(LWIP_COMPAT_MUTEX_ALLOWED)
^
Setting LWIP_TCPIP_CORE_LOCKING is meaningless for NO_SYS targets,
therefore checking if LWIP_COMPAT_MUTEX is set does not make sense.
Introduced by 42dfa71f97: Make LWIP_TCPIP_CORE_LOCKING==1 the default
(and warn if LWIP_COMPAT_MUTEX==1 in that case as mutexes are required
to prevent priority inversion on tcpip_thread operations)
issue 1:
sys_arch_sem_wait() is supposed to return an elapsed time in ms, what could
happen given a > 1 kHz calling rate for high throughput systems is that it
might always returns 0 ms. This is a problem for systems which compute the
elapsed time from a high precision clock source.
This is what is currently happening in the unix port in sys_arch_sem_wait():
start time -> 1000000000; // ns
-- less than a ms before an event arrive --
end time -> 1000xxxxxx; // ns
return value -> (end time - start time)/1000000 -> 0
The return value is used to reduce the next timer interval, if
sys_arch_sem_wait() always return 0 no more timers are fired anymore
issue 2:
The current timer implementation for !NO_SYS targets only count elapsed
time while -waiting- for semaphore and doesn't count at all the time
spent by the stack to process packets. For CPU bound traffic patterns no
more timers are fired anymore.
Both are serious design issues which cannot be easily fixed without reworking
everything. This patch uses the properly implemented timers for NO_SYS targets
for !NO_SYS targets and merge them both into one single timers implementation.
Since allowing input validation to trip the ASSERT handler is bad,
let's just drop the packets instead if validation fails.
Signed-off-by: sg <goldsimon@gmx.de>
dhcp_discover_request_options is u8_t array, so the result is the same.
But use LWIP_ARRAYSIZE to get the number of array entries is better
because it works for all types.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
lwip/src/core/timers.c: In function ‘sys_check_timeouts’:
lwip/src/core/timers.c:328:5: error: "PBUF_POOL_FREE_OOSEQ" is not defined [-Werror=undef]
#if PBUF_POOL_FREE_OOSEQ
Fix it by declaring an empty PBUF_CHECK_FREE_OOSEQ() function if feature is
not enabled.
Simon says:
ppp_init() does not seem to be used. The only thing it does is calling
magic_init(), which is not required because it its called again later
from ppp_input().
Also, the time from startup is rather constant, so calling sys_jiffies()
from ppp_init() does not create a random number.
Sockets bound to a multicast address could not transmit multicast
packets because the pcb local address did not match the netif address
even if the outgoing netif was resolved correctly.
To correct the issue, pcbs with a multicast local address will use
the outgoing netif address as the source address in IPv4.
It's already done by memset(0). This was missed in commit 5794ac2340
"tcp_alloc(): remove explicit =0 already done by memset(0)", fix it.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
The old approach called udp_bind() on each of the PCBs, which puts them into udp_pcbs list. The PCBs were iterated on all non-DHCP udp_inputs() with no effect.
My cleanup removes the special handling in udp.c, and uses only one DHCP UDP PCB to catch all DHCP messages from all netifs. The dhcp_recv function then checks whether ip_current_input_netif() has DHCP enabled - if not, the message is ignored. The PCB is only created/registered when one or more PCBs have DHCP enabled.
This commit adds support to the sockets and netconn layer to update the
backlog by calling listen when the netconn is already in the listen state.
When backlog is not enabled, the call returns successfully
This commit also introduces a macro for setting the backlog value that
prevents a 0 sized (invalid) backlog
Create special IP address type "IPADDR_TYPE_ANY" for it.
SNMP uses new feature in non-netconn mode.
TODO: Same for TCP & RAW, adapt NETCONN to use this feature
- Move local PCB matching code in a function that can be reused in SO_REUSE && SO_REUSE_RXTOALL case.
- Some checks have been written in the dual-stack version and then repeated with the ipv6-only version. Example:
IPv6 only: ip6_addr_ismulticast(ip6_current_dest_addr())
IPv4 AND IPv6: ip_addr_ismulticast(ip_current_dest_addr())
sign_extension: Suspicious implicit sign extension: count with type unsigned short (16 bits, unsigned) is promoted in count * size to type int (32 bits, signed), then sign-extended to type unsigned long (64 bits, unsigned). If count * size is greater than 0x7FFFFFFF, the upper bits of the result will all be 1.
The usages of memp_names are under either LWIP_DEBUG in stats_init,
or under LWIP_STATS_DISPLAY in stats_display_memp.
Fix below build warning:
lwip/src/core/stats.c:53:21: error: 'memp_names' defined but not used [-Werror=unused-variable]
static const char * memp_names[] = {
^
cc1: all warnings being treated as errors
Reported-by: David Fernandez
Fixes: 2f2a75a6d9fd ("stats: Move memp_names table out of stats_init/stats_display_memp functions")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
This was missed in commit aa0e41c389
("task #12178: hardware checksum capabilities can be configured per netif"),
fix it.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
IP6_HLEN is only defined when LWIP_IPV6, IP_HLEN is only defined when LWIP_IPV4.
This fixes build error in !LWIP_IPV4 || !LWIP_IPV6 cases.
Fixes: f2c7e9c939 ("raw: Remove unnecessary #if guard around PCB_ISIPV6() calls")
Reported-by: Erik Ekman
Signed-off-by: Axel Lin <axel.lin@ingics.com>
In case of IP_REASS_FREE_OLDEST==0, the argument clen of
ip_reass_enqueue_new_datagram() will not used and leads
the compiler to a warning.
Signed-off-by: Stephan Linz <linz@li-pro.net>
PCB_ISIPV6() macro is well defined for all cases (LWIP_IPV4 && LWIP_IPV6,
LWIP_IPV4 only and LWIP_IPV6 only), thus remove the unnecessary #if guard
around PCB_ISIPV6() calls.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
