Zephyr TCP/IP replacement

[danielinux]

• Added routing tables support for IPv4 routing
• Added patches to replace stock TCP/IP from Zephyr with wolfIP

[Copilot]

Pull request overview

This PR extends wolfIP with an IPv4 routing table (static routes + longest-prefix-match selection) and adds an out-of-tree Zephyr port that replaces Zephyr’s native IPv4/TCP/UDP stack with wolfIP via a custom L2 and socket-offload integration.

Changes:

• Added routing table storage and public APIs (wolfIP_route_*) plus route-aware next-hop/interface selection.
• Added a DNS server getter API (wolfIP_dns_server_get) and accompanying unit tests.
• Added Zephyr port documentation and patch set (glue layer, L2 module, net-shell integration, and a TAP echo sample).

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
wolfip.h	Adds route info struct, route API declarations, and POSIX-type inclusion tweaks; adds DNS server getter prototype.
src/wolfip.c	Implements route table, LPM route lookup, route-aware nexthop/egress selection, and DNS server getter.
src/test/unit/unit.c	Registers new unit tests for routing table behavior and DNS getter.
src/test/unit/unit_tests_proto.c	Adds unit tests covering route LPM, default route deletion/fallback, update semantics, and connected-subnet precedence; adds DNS getter test.
port/zephyr/README.md	Documents the Zephyr port design, usage, patch structure, and limitations.
port/zephyr/patches/0001-wolfip-glue-and-public-api.patch	Adds Zephyr glue/runtime, control wrappers, Kconfig/CMake integration, and public Zephyr header.
port/zephyr/patches/0002-net-l2-wolfip-module.patch	Adds NET_L2_WOLFIP to intercept raw Ethernet frames and delegate L3+ to wolfIP.
port/zephyr/patches/0003-net-shell-wolfip.patch	Makes Zephyr net-shell commands work when wolfIP is enabled (route/arp/ipv4/dhcp/ping/tcp/udp, etc.).
port/zephyr/patches/0004-sample-wolfip-tap-echo.patch	Adds a Zephyr native_sim TAP-based TCP/UDP echo sample using wolfIP.

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[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #114

Scan targets checked: wolfip-bugs, wolfip-src
Findings: 1

Low (1)

Functional inconsistency in TX interface selection and MAC address derivation

Function: wolfIP_select_nexthop_ex, ip_output_add_header, wolfIP_ll_send_frame, arp_lookup
Category: Logic Error

The routed tx_if from wolfIP_select_nexthop_ex is used for wolfIP_ll_send_frame and arp_lookup operations, while ip_output_add_header still derives the Ethernet source MAC from wolfIP_socket_if_idx(t). This represents a functional inconsistency where different code paths may select different interfaces for routing decisions and MAC address derivation.

Recommendation: Verify that the MAC address derivation in ip_output_add_header is correctly synchronized with the interface selected by wolfIP_select_nexthop_ex, or document the intentional separation of concerns if this behavior is by design. This should be verified to ensure consistent interface selection across the TX path.

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This review was generated automatically by Fenrir. Findings are non-blocking.

[danielinux]

Fenrir has a point in its comment, but the refactor needed is outside the scope for this PR, and there is no functional issue associated, so leaving as is.

[dgarske]

Very nice!

[dgarske]

Testing with Zephyr native_sim build:

FAIL ; wolfip.h redefines struct iovec/struct msghdr under Zephyr's POSIX layer

Zephyr native_sim build

Workspace set up at ~/zephyr-workspace/:

• west 1.5.0 in ~/zephyr-venv/
• Zephyr v4.4.0 shallow-cloned (release 684c9e8f)
• All modules updated via west update --narrow -o=--depth=1
• Zephyr SDK 1.0.1 minimal (host tools) installed at ~/zephyr-sdk/zephyr-sdk-1.0.1/
• ~/wolfip -> /home/davidgarske/GitHub/wolfip-alt symlink so
  ${ZEPHYR_BASE}/../../wolfip resolves (per subsys/net/lib/wolfip/CMakeLists.txt:5)

All 4 patches applied cleanly (no --whitespace=nowarn complaints,
no hand fixups):

0001-wolfip-glue-and-public-api.patch     OK
0002-net-l2-wolfip-module.patch           OK
0003-net-shell-wolfip.patch               OK
0004-sample-wolfip-tap-echo.patch         OK

CMake configure succeeded. Build FAILED partway through, while compiling
/home/davidgarske/wolfip/src/wolfip.c for the wolfip library object.

Root cause: redefinition of struct iovec/struct msghdr on Zephyr

In file included from .../zephyr/include/zephyr/net/net_ip.h:2304,
                 from .../zephyr/include/zephyr/net/socket.h:33,
                 from .../zephyr/include/zephyr/posix/sys/socket.h:13,
                 from .../wolfip/wolfip.h:286,
                 from .../wolfip/src/wolfip.c:32:
.../zephyr/include/zephyr/net/net_compat.h:112:35: error: redefinition of
  struct net_iovec
  112 | #define iovec   net_iovec
.../wolfip/wolfip.h:295:8: note: in expansion of macro iovec
  295 | struct iovec { void *iov_base; size_t iov_len; };
.../zephyr/include/zephyr/net/net_ip.h:287:8: note: originally defined here
  287 | struct net_iovec {
...same error pattern for msghdr -> net_msghdr at wolfip.h:296...

Walkthrough of wolfip/wolfip.h:278-305:

#if defined(__has_include)
#if __has_include(<sys/socket.h>)
#include <sys/socket.h>                 /* Zephyr provides this; it transitively
                                           defines `iovec` -> `net_iovec` and
                                           `msghdr` -> `net_msghdr` */
#if __has_include(<sys/uio.h>)
#include <sys/uio.h>                    /* Zephyr does NOT ship this */
#define WOLFIP_HAVE_POSIX_TYPES 1
#endif
#endif
#endif

#ifndef WOLFIP_HAVE_POSIX_TYPES         /* still undefined under Zephyr */
struct iovec { void *iov_base; size_t iov_len; };   /* expands to
                                                       struct net_iovec - clash */
struct msghdr { ... };                              /* same for msghdr */
#endif

Under Zephyr's POSIX layer, <sys/socket.h> exists but <sys/uio.h> does not.
The current logic assumes POSIX systems ship them together. They don't on
Zephyr.

Suggested fix (for the author - not applied here)

Add Zephyr to the systems whose system iovec/msghdr is considered authoritative:

#if defined(__ZEPHYR__)
/* Zephyr's <zephyr/net/net_compat.h> aliases iovec/msghdr to net_* via
 * macros; the POSIX layer's <sys/socket.h> drags it in. Use those instead
 * of our local fallbacks. */
#define WOLFIP_HAVE_POSIX_TYPES 1
#endif

#if !defined(WOLFIP_HAVE_POSIX_TYPES) && defined(__has_include)
... existing block ...
#endif

Or, equivalently, gate the local struct definitions on !defined(iovec) /
!defined(msghdr) after the include block - the Zephyr macros block their
expansion in the same way.