Previously, IPv6 routing could select a next-hop router on a netif
that was down or disconnected, potentially resulting in packets being
dropped unnecessarily. This patch changes router selection to take
into account the state of the router's associated netif, eliminating
such unnecessary packet loss.
Also, this patch fixes the test for router validity, which was
erroneously based on the router's invalidation timer rather than its
neighbor cache entry state. Given that an expired router has no
associated neighbor cache entry, no invalid routers would previously
ever be returned.
Finally, this patch also adds round-robin selection of routers that
are not known to be reachable or probably reachable, as per RFC 4861
Sec. 6.3.6 point (2). Support for this feature was partially present
but not actually functional.
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.
Previously, Duplicate Address Detection (DAD) would work only for the
link-local address. For DAD-spawned Neighbor Solicitation requests for
any other address, the request would use the link-local address as the
source, meaning the other side would send a targeted reply (RFC 4861
Sec. 7.2.4). However, the nd6 implementation currently does not
consider targeted replies for DAD--even though technically an RFC 4862
Sec. 5.4.4 violation--supposedly because no real-world scenario could
trigger that case. The combination of these factors resulted in DAD
being entirely ineffective for non-link-local addresses.
This patch forces all DAD-spawned Neighbor Solicitation packets to use
the unspecified ('any') address as source, as per RFC 4862 Sec. 5.4.2.
As a result, other nodes would reply with multicast replies, for which
there is appropriate DAD checking code.
The patch also makes a slight rearrangement of statements such that
MLD join messages are sent before the NS packets, rather than after.
In the cases that nd6 checks whether the interface is up before
sending a packet, also check whether the link is up. Without this
additional check, temporary link downtime could easily result in
unnecessary false negatives for Duplicate Address Detection.
In addition, use the netif abstraction macros to perform the checks.
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>
