From 020fae874b6ec17f2a1cfc14d63007a3399335cf Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Sat, 23 May 2026 12:04:04 +0200
Subject: [PATCH 1/5] Xemomai EVL: Abort on evl_attach_self() failed

If this fails, everything beaks and there are a thon of error messages.
So better abort here
---
 src/rtapi/uspace_xenomai_evl.cc | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/rtapi/uspace_xenomai_evl.cc b/src/rtapi/uspace_xenomai_evl.cc
index 6f1988337b0..f4965deb19a 100644
--- a/src/rtapi/uspace_xenomai_evl.cc
+++ b/src/rtapi/uspace_xenomai_evl.cc
@@ -124,6 +124,7 @@ struct EvlApp : RtapiApp {
             int tfd = evl_attach_self("linuxcnc-thread:%d", gettid());
             if (tfd < 0) {
                 rtapi_print("evl_attach_self() failed ret %i errno %i\n", tfd, errno);
+                return nullptr;
             }
         }
 

From d1731461836563cda7e9279bbb40d85091ab61d8 Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Fri, 29 May 2026 23:26:26 +0200
Subject: [PATCH 2/5] Xenomai EVL network for Hostmot2

Split into two network implementations, one for posix and
one for evl.

There are now two modules: hm2_eth and hm2_eth_evl.
---
 src/Makefile                                  |  13 +-
 src/hal/drivers/mesa-hostmot2/hm2_eth.c       | 197 ++---------
 src/hal/drivers/mesa-hostmot2/hm2_eth.h       |  12 +
 src/hal/drivers/mesa-hostmot2/hm2_eth_net.c   | 173 ++++++++++
 src/hal/drivers/mesa-hostmot2/hm2_eth_net.h   |  40 +++
 .../drivers/mesa-hostmot2/hm2_eth_net_evl.c   | 313 ++++++++++++++++++
 6 files changed, 577 insertions(+), 171 deletions(-)
 create mode 100644 src/hal/drivers/mesa-hostmot2/hm2_eth_net.c
 create mode 100644 src/hal/drivers/mesa-hostmot2/hm2_eth_net.h
 create mode 100644 src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c

diff --git a/src/Makefile b/src/Makefile
index 69952ddeac9..6ddb0f28e70 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1004,6 +1004,9 @@ obj-$(CONFIG_HOSTMOT2) += hostmot2.o hm2_test.o hm2_pci.o hm2_7i43.o hm2_7i90.o
 obj-$(CONFIG_HOSTMOT2) += hm2_modbus.o
 ifeq ($(BUILD_SYS),uspace)
 obj-$(CONFIG_HOSTMOT2) += hm2_eth.o
+ifeq ($(CONFIG_USPACE_XENOMAI_EVL),y)
+obj-$(CONFIG_HOSTMOT2) += hm2_eth_evl.o
+endif
 obj-$(CONFIG_HOSTMOT2) += hm2_spi.o hm2_rpspi.o hm2_spix.o
 endif
 hostmot2-objs :=			  \
@@ -1049,6 +1052,11 @@ hm2_pci-objs  :=			  \
     $(MATHSTUB)
 hm2_eth-objs  :=			  \
     hal/drivers/mesa-hostmot2/hm2_eth.o   \
+    hal/drivers/mesa-hostmot2/hm2_eth_net.o   \
+    $(MATHSTUB)
+hm2_eth_evl-objs  :=			  \
+    hal/drivers/mesa-hostmot2/hm2_eth.o   \
+    hal/drivers/mesa-hostmot2/hm2_eth_net_evl.o   \
     $(MATHSTUB)
 hm2_spi-objs  :=			  \
     hal/drivers/mesa-hostmot2/hm2_spi.o   \
@@ -1286,7 +1294,7 @@ modules: $(patsubst %.o,../rtlib/%.so,$(obj-m))
 	$(Q)objdump -w -j .rtapi_export -t objects/$*.tmp \
 	| awk 'BEGIN{print "{ global :"} /rtapi_exported_/{printf("%s;\n", substr($$6,16))} END{print "local : * ; };"}' \
 	> objects/$*.ver
-	$(Q)$(CC) -shared -Bsymbolic -Wl,--version-script,objects/$*.ver -o $@ $^ -lm $(LDFLAGS)
+	$(Q)$(CC) -shared -Bsymbolic -Wl,--version-script,objects/$*.ver -o $@ $^ -lm $(XENOMAI_EVL_LDFLAGS) $(LDFLAGS)
 	$(Q)chmod -x $@
 
 RTFLAGS += -fno-strict-aliasing -fwrapv
@@ -1297,7 +1305,7 @@ $(sort $(filter-out objects/rtemc/tp/cruckig/%,$(RTOBJS))) : objects/rt%.o : %.c
 	@rm -f $@
 	@mkdir -p $(dir $@)
 	$(Q)$(CC) -c $(OPT) $(DEBUG) $(EXTRA_DEBUG) -DRTAPI \
-		$(EXTRA_CFLAGS) \
+		$(EXTRA_CFLAGS) $(XENOMAI_EVL_CFLAGS) \
 		-MP -MD -MF "${@:.o=.d}" -MT "$@" \
 		$< -o $@
 
@@ -1397,6 +1405,7 @@ endif
 ../rtlib/hal_parport$(MODULE_EXT): $(addprefix objects/rt,$(hal_parport-objs))
 ../rtlib/hal_ppmc$(MODULE_EXT): $(addprefix objects/rt,$(hal_ppmc-objs))
 ../rtlib/hm2_eth$(MODULE_EXT): $(addprefix objects/rt,$(hm2_eth-objs))
+../rtlib/hm2_eth_evl$(MODULE_EXT): $(addprefix objects/rt,$(hm2_eth_evl-objs))
 ../rtlib/hm2_spi$(MODULE_EXT): $(addprefix objects/rt,$(hm2_spi-objs))
 ../rtlib/hm2_rpspi$(MODULE_EXT): $(addprefix objects/rt,$(hm2_rpspi-objs))
 ../rtlib/hm2_spix$(MODULE_EXT): $(addprefix objects/rt,$(hm2_spix-objs))
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.c b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
index 5d89756a97a..94bd4732457 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
@@ -46,6 +46,7 @@
 #include "hostmot2-lowlevel.h"
 #include "hostmot2.h"
 #include "hm2_eth.h"
+#include "hm2_eth_net.h"
 
 struct kvlist {
     struct rtapi_list_head list;
@@ -452,17 +453,11 @@ static const char *hm2_8cSS_pin_names[] = {
 
 };
 
-#define UDP_PORT 27181
-#define SEND_TIMEOUT_US 10
-#define RECV_TIMEOUT_US 10
 #define READ_PCK_DELAY_NS 10000
 
-static hm2_eth_t boards[MAX_ETH_BOARDS];
+static hm2_eth_t boards[MAX_ETH_BOARDS]={};
 
-/// ethernet io functions
-
-static int eth_socket_send(int sockfd, const void *buffer, int len, int flags);
-static int eth_socket_recv(int sockfd, void *buffer, int len, int flags);
+/// firewall functions
 
 // hm2_eth installs firewall rules to isolate the dedicated Mesa
 // interface from non-realtime traffic.  rtapi_app raises CAP_NET_ADMIN
@@ -584,7 +579,7 @@ static fw_state_t fw_state = FW_UNRESOLVED;
 // Resolve and bring up the firewall backend on first call, caching the
 // result.  Returns true when a backend is ready, false when isolation
 // is unavailable or disabled.
-static bool use_firewall() {
+bool use_firewall() {
     if(fw_state != FW_UNRESOLVED)
         return fw_state == FW_READY;
 
@@ -631,7 +626,7 @@ static bool use_firewall() {
 
 // Drop all rules from our chain/table but keep the chain in place, so a
 // fresh set can be installed on (re-)init.
-static void clear_firewall() {
+void clear_firewall() {
     if(!use_firewall()) return;
     switch(fw_backend) {
     case FW_IPTABLES:
@@ -672,7 +667,7 @@ static char* inet_ntoa_buf(struct in_addr in, char *buf, size_t n) {
     return buf;
 }
 
-static char* fetch_ifname(int sockfd, char *buf, size_t n) {
+char* fetch_ifname(int sockfd, char *buf, size_t n) {
     struct sockaddr_in srcaddr;
     struct ifaddrs *ifa, *it;
 
@@ -699,7 +694,7 @@ static char* fetch_ifname(int sockfd, char *buf, size_t n) {
     return NULL;
 }
 
-static int install_firewall_board(int sockfd) {
+int install_firewall_board(int sockfd) {
     struct sockaddr_in srcaddr, dstaddr;
     char srchost[16], dsthost[16]; // enough for 255.255.255.255\0
     char dport_s[8], sport_s[8];
@@ -744,7 +739,7 @@ static int install_firewall_board(int sockfd) {
     return 0;
 }
 
-static int install_firewall_perinterface(const char *ifbuf) {
+int install_firewall_perinterface(const char *ifbuf) {
     // Without these rules, 'ping' spews a lot of "Packet filtered"
     // messages.  With them, ping prints 'ping: sendmsg: Operation not
     // permitted' once per second.
@@ -788,16 +783,16 @@ static int install_firewall_perinterface(const char *ifbuf) {
     return 0;
 }
 
-static int fetch_hwaddr(const char *board_ip, int sockfd, unsigned char buf[6]) {
+int fetch_hwaddr(hm2_eth_t *board, unsigned char buf[6]) {
     lbp16_cmd_addr packet;
     unsigned char response[6];
     LBP16_INIT_PACKET4(packet, 0x4983, 0x0002);
-    int res = eth_socket_send(sockfd, &packet, sizeof(packet), 0);
+    int res = eth_socket_send(board, &packet, sizeof(packet), 0);
     if(res < 0) return -errno;
 
     int i=0;
     do {
-        res = eth_socket_recv(sockfd, &response, sizeof(response), 0);
+        res = eth_socket_recv(board, &response, sizeof(response), 0);
     } while(++i < 10 && res < 0 && errno == EAGAIN);
     if(res < 0) return -errno;
 
@@ -805,144 +800,11 @@ static int fetch_hwaddr(const char *board_ip, int sockfd, unsigned char buf[6])
     for(i=0; i<6; i++) buf[i] = response[5-i];
 
     LL_PRINT("%s: INFO: Hardware address (MAC): %02x:%02x:%02x:%02x:%02x:%02x\n",
-        board_ip, buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);
-
-    return 0;
-}
-
-int ioctl_siocsarp(void *arg) {
-    hm2_eth_t *board = (hm2_eth_t *)arg;
-    return ioctl(board->sockfd, SIOCSARP, &board->req);
-}
-
-int ioctl_siocdarp(void *arg) {
-    hm2_eth_t *board = (hm2_eth_t *)arg;
-    return ioctl(board->sockfd, SIOCDARP, &board->req);
-}
-
-static int init_board(hm2_eth_t *board, const char *board_ip) {
-    int ret;
-
-    board->sockfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
-    if (board->sockfd < 0) {
-        LL_PRINT("ERROR: can't open socket: %s\n", strerror(errno));
-        return -errno;
-    }
-    board->server_addr.sin_family = AF_INET;
-    board->server_addr.sin_port = htons(LBP16_UDP_PORT);
-    board->server_addr.sin_addr.s_addr = inet_addr(board_ip);
-
-    board->local_addr.sin_family      = AF_INET;
-    board->local_addr.sin_addr.s_addr = INADDR_ANY;
-
-    ret = connect(board->sockfd, (struct sockaddr *) &board->server_addr, sizeof(struct sockaddr_in));
-    if (ret < 0) {
-        LL_PRINT("ERROR: can't connect: %s\n", strerror(errno));
-        return -errno;
-    }
-
-    if(!use_firewall()) {
-        LL_PRINT(\
-"WARNING: Unable to restrict other access to the hm2-eth device.\n"
-"This means that other software using the same network interface can violate\n"
-"realtime guarantees.  See hm2_eth(9) for more information.\n");
-    }
-
-    struct timeval timeout;
-    timeout.tv_sec = 0;
-    timeout.tv_usec = RECV_TIMEOUT_US;
-
-    ret = setsockopt(board->sockfd, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));
-    if (ret < 0) {
-        LL_PRINT("ERROR: can't set receive timeout socket option: %s\n", strerror(errno));
-        return -errno;
-    }
-
-    timeout.tv_usec = SEND_TIMEOUT_US;
-    ret = setsockopt(board->sockfd, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout));
-    if (ret < 0) {
-        LL_PRINT("ERROR: can't set send timeout socket option: %s\n", strerror(errno));
-        return -errno;
-    }
-
-    memset(&board->req, 0, sizeof(board->req));
-    struct sockaddr_in *sin;
-
-    sin = (struct sockaddr_in *) &board->req.arp_pa;
-    sin->sin_family = AF_INET;
-    sin->sin_addr.s_addr = inet_addr(board_ip);
-
-    board->req.arp_ha.sa_family = AF_LOCAL;
-    board->req.arp_flags = ATF_PERM | ATF_COM;
-    ret = fetch_hwaddr( board_ip, board->sockfd, (void*)&board->req.arp_ha.sa_data );
-    if(ret < 0) {
-        LL_PRINT("ERROR: Could not retrieve hardware address (MAC) of %s: %s\n", board_ip, strerror(-ret));
-        return ret;
-    }
-
-    // Pinning the ARP entry needs CAP_NET_ADMIN; rootless without setcap
-    // fails with EPERM.  Best-effort, not fatal: fall back to dynamic ARP
-    // so the board still loads.  Clear ATF_PERM so the SIOCDARP teardown
-    // in close_board() does not try to remove an entry we never set.
-    ret = ioctl_siocsarp(board);
-    if(ret < 0) {
-        LL_PRINT("WARNING: ioctl SIOCSARP failed: %s; continuing with "
-                 "dynamic ARP.  Install file capabilities (sudo make "
-                 "setcap) or run setuid to pin the board's ARP entry and "
-                 "avoid occasional transmit latency.\n", strerror(errno));
-        board->req.arp_flags &= ~ATF_PERM;
-    }
-
-    // install_firewall_board() is a no-op when no firewall backend is
-    // available (rootless install without CAP_NET_ADMIN, or
-    // firewall=none), so it is safe to call unconditionally.
-    ret = install_firewall_board(board->sockfd);
-    if(ret < 0) return ret;
-
-    board->write_packet_ptr = board->write_packet;
-    board->read_packet_ptr = board->read_packet;
+        board->ip, buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);
 
     return 0;
 }
 
-static int close_board(hm2_eth_t *board) {
-    int ret;
-    board->llio.reset(&board->llio);
-
-    clear_firewall();
-
-    if(board->req.arp_flags & ATF_PERM) {
-        ret = ioctl_siocdarp(board);
-        if(ret < 0) perror("ioctl SIOCDARP");
-    }
-    ret = shutdown(board->sockfd, SHUT_RDWR);
-    if (ret == -1)
-        LL_PRINT("ERROR: can't shutdown socket: %s\n", strerror(errno));
-    
-    ret = close(board->sockfd);
-    if (ret == -1)
-        LL_PRINT("ERROR: can't close socket: %s\n", strerror(errno));
-    
-    return ret < 0 ? -errno : 0;
-}
-
-static int eth_socket_send(int sockfd, const void *buffer, int len, int flags) {
-    return send(sockfd, buffer, len, flags);
-}
-
-static int eth_socket_recv(int sockfd, void *buffer, int len, int flags) {
-    return recv(sockfd, buffer, len, flags);
-}
-
-static int eth_socket_recv_loop(int sockfd, void *buffer, int len, int flags, long timeout) {
-    long long end = rtapi_get_time() + timeout;
-    int result;
-    do {
-        result = eth_socket_recv(sockfd, buffer, len, flags);
-    } while(result < 0 && rtapi_get_time() < end);
-    return result;
-}
-
 /// hm2_eth io functions
 
 static int hm2_eth_read(hm2_lowlevel_io_t *this, rtapi_u32 addr, void *buffer, int size) {
@@ -968,7 +830,7 @@ static int hm2_eth_read(hm2_lowlevel_io_t *this, rtapi_u32 addr, void *buffer, i
 
     LBP16_INIT_PACKET4(read_packet, CMD_READ_HOSTMOT2_ADDR32_INCR(size/4), addr & 0xFFFF);
 
-    send = eth_socket_send(board->sockfd, (void*) &read_packet, sizeof(read_packet), 0);
+    send = eth_socket_send(board, (void*) &read_packet, sizeof(read_packet), 0);
     if(send < 0)
         LL_PRINT("ERROR: sending packet: %s\n", strerror(errno));
     LL_PRINT_IF(debug, "read(%d) : PACKET SENT [CMD:%02X%02X | ADDR: %02X%02X | SIZE: %d]\n", board->read_cnt, read_packet.cmd_hi, read_packet.cmd_lo,
@@ -976,7 +838,7 @@ static int hm2_eth_read(hm2_lowlevel_io_t *this, rtapi_u32 addr, void *buffer, i
     t1 = rtapi_get_time();
     do {
         errno = 0;
-        recv = eth_socket_recv(board->sockfd, (void*) &tmp_buffer, size, 0);
+        recv = eth_socket_recv(board, (void*) &tmp_buffer, size, 0);
         if(recv < 0) rtapi_delay(READ_PCK_DELAY_NS);
         t2 = rtapi_get_time();
         i++;
@@ -1021,7 +883,7 @@ static int hm2_eth_send_queued_reads(hm2_lowlevel_io_t *this) {
     board->queue_reads_count++;
     board->queue_buff_size += 8;
 
-    send = eth_socket_send(board->sockfd, (void*) &board->read_packet, board->read_packet_ptr - board->read_packet, 0);
+    send = eth_socket_send(board, (void*) &board->read_packet, board->read_packet_ptr - board->read_packet, 0);
     if(send < 0) {
         LL_PRINT("ERROR: sending packet: %s\n", strerror(errno));
         return 0;
@@ -1085,7 +947,7 @@ static int hm2_eth_receive_queued_reads(hm2_lowlevel_io_t *this) {
     do {
 do_recv_packet:
         errno = 0;
-        recv = eth_socket_recv(board->sockfd, (void*) &tmp_buffer, board->queue_buff_size, MSG_DONTWAIT);
+        recv = eth_socket_recv(board, (void*) &tmp_buffer, board->queue_buff_size, MSG_DONTWAIT);
         if(recv < 0) rtapi_delay(READ_PCK_DELAY_NS);
         t2 = rtapi_get_time();
         i++;
@@ -1130,7 +992,7 @@ static int hm2_eth_reset(hm2_lowlevel_io_t *this) {
     // Make the watchdog timer bite in 1ns from now
     lbp16_cmd_addr_data32 bite_packet;
     LBP16_INIT_PACKET8(bite_packet, CMD_WRITE_HOSTMOT2_ADDR32_INCR(1), HM2_ADDR_WATCHDOG, 0x0001);
-    int ret = eth_socket_send(board->sockfd, (void*) &bite_packet, sizeof(bite_packet), 0);
+    int ret = eth_socket_send(board, (void*) &bite_packet, sizeof(bite_packet), 0);
     if(ret < 0) perror("eth_socket_send(bite_packet)");
     return ret < 0 ? -errno : 0;
 }
@@ -1170,7 +1032,7 @@ static int hm2_eth_write(hm2_lowlevel_io_t *this, rtapi_u32 addr, const void *bu
     memcpy(packet.tmp_buffer, buffer, size);
     LBP16_INIT_PACKET4(packet.wr_packet, CMD_WRITE_HOSTMOT2_ADDR32_INCR(size/4), addr & 0xFFFF);
 
-    send = eth_socket_send(board->sockfd, (void*) &packet, sizeof(lbp16_cmd_addr) + size, 0);
+    send = eth_socket_send(board, (void*) &packet, sizeof(lbp16_cmd_addr) + size, 0);
     if(send < 0)
         LL_PRINT("ERROR: sending packet: %s\n", strerror(errno));
     LL_PRINT_IF(debug, "write(%d): PACKET SENT [CMD:%02X%02X | ADDR: %02X%02X | SIZE: %d]\n", board->write_cnt, packet.wr_packet.cmd_hi, packet.wr_packet.cmd_lo,
@@ -1194,7 +1056,7 @@ static int hm2_eth_send_queued_writes(hm2_lowlevel_io_t *this) {
     board->write_packet_size += (sizeof(*packet) + 4);
     
     t0 = rtapi_get_time();
-    send = eth_socket_send(board->sockfd, (void*) &board->write_packet, board->write_packet_size, 0);
+    send = eth_socket_send(board, (void*) &board->write_packet, board->write_packet_size, 0);
     if(send < 0) {
         LL_PRINT("ERROR: sending packet: %s\n", strerror(errno));
         return 0;
@@ -1246,12 +1108,12 @@ static int hm2_eth_probe(hm2_eth_t *board) {
     char llio_name[16] = {};
 
     LBP16_INIT_PACKET4(read_packet, CMD_READ_BOARD_INFO_ADDR16_INCR(16/2), 0);
-    send = eth_socket_send(board->sockfd, (void*) &read_packet, sizeof(read_packet), 0);
+    send = eth_socket_send(board, (void*) &read_packet, sizeof(read_packet), 0);
     if(send < 0) {
         LL_PRINT("ERROR: sending packet: %s\n", strerror(errno));
         return -errno;
     }
-    recv = eth_socket_recv_loop(board->sockfd, (void*) &board_name, 16, 0,
+    recv = eth_socket_recv_loop(board, (void*) &board_name, 16, 0,
                 200 * 1000 * 1000);
     if(recv < 0) {
         LL_PRINT("ERROR: receiving packet: %s\n", strerror(errno));
@@ -1736,7 +1598,7 @@ int rtapi_app_main(void) {
 
     LL_PRINT("loading Mesa AnyIO HostMot2 ethernet driver version " HM2_ETH_VERSION "\n");
 
-    ret = hal_init(HM2_LLIO_NAME);
+    ret = hal_init(HM2_LLIO_MODULE_NAME);
     if (ret < 0)
         return ret;
     comp_id = ret;
@@ -1768,21 +1630,18 @@ int rtapi_app_main(void) {
     }
 
     for(i = 0; i<num_boards; i++) {
-        char ifbuf[64]; // more than enough for eth0
-        char *ifptr = fetch_ifname(boards[i].sockfd, ifbuf, sizeof(ifbuf));
-        if(!ifptr) {
-            LL_PRINT("failed to retrieve interface name for board");
-            continue;
-        } 
-        boards[i].read_cnt = boards[i].write_cnt = 0;
-        int *added = kvlist_lookup(&ifnames, ifptr);
+        int *added = kvlist_lookup(&ifnames, boards[i].ifname);
         if(!added)
             goto error;
         if(*added) continue;
-        install_firewall_perinterface(ifptr);
+        install_firewall_perinterface(boards[i].ifname);
         *added = 1;
     }
 
+    for(i = 0; i<num_boards; i++) {
+        init_board_realtime(&boards[i]);
+    }
+
     hal_ready(comp_id);
 
     return 0;
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.h b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
index 2e25e231c0d..69a3a07218d 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.h
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
@@ -42,6 +42,11 @@ typedef struct {
     struct sockaddr_in local_addr;
     struct sockaddr_in server_addr;
 
+    char ip[64];
+    char ifname[64];
+    //Only for evl implementation
+    bool is_evl_oob_active;
+
     rtapi_u8 read_packet[1400];
     rtapi_u8 *read_packet_ptr;
     hm2_read_queue_entry_t queue_reads[MAX_ETH_READS];
@@ -72,4 +77,11 @@ typedef struct {
     } *hal;
 } hm2_eth_t;
 
+bool use_firewall();
+int install_firewall_board(int sockfd);
+int install_firewall_perinterface(const char *ifbuf);
+void clear_firewall();
+char* fetch_ifname(int sockfd, char *buf, size_t n);
+int fetch_hwaddr(hm2_eth_t *board, unsigned char buf[6]);
+
 #endif
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net.c
new file mode 100644
index 00000000000..ad0a7fbcc7f
--- /dev/null
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net.c
@@ -0,0 +1,173 @@
+/*    This is a component of LinuxCNC
+ *    Copyright 2013,2014 Michael Geszkiewicz <micges@wp.pl>,
+ *    Jeff Epler <jepler@unpythonic.net>
+ *
+ *    This program is free software; you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation; either version 2 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <sys/fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <net/if_arp.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <rtapi.h>
+#include <rtapi_string.h>
+
+#include "hostmot2-lowlevel.h"
+#include "hm2_eth_net.h"
+
+char* HM2_LLIO_MODULE_NAME="hm2_eth";
+
+/// ethernet io functions
+
+int init_board(hm2_eth_t *board, const char *board_ip) {
+    int ret;
+    LL_PRINT("%s: INFO: init board (POSIX)\n", board_ip);
+    board->sockfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
+    if (board->sockfd < 0) {
+        LL_PRINT("ERROR: can't open socket: %s\n", strerror(errno));
+        return -errno;
+    }
+
+    board->server_addr.sin_family = AF_INET;
+    board->server_addr.sin_port = htons(LBP16_UDP_PORT);
+    board->server_addr.sin_addr.s_addr = inet_addr(board_ip);
+
+    board->local_addr.sin_family      = AF_INET;
+    board->local_addr.sin_addr.s_addr = INADDR_ANY;
+
+    ret = connect(board->sockfd, (struct sockaddr *) &board->server_addr, sizeof(struct sockaddr_in));
+    if (ret < 0) {
+        LL_PRINT("ERROR: can't connect: %s\n", strerror(errno));
+        return -errno;
+    }
+
+    strncpy(board->ip, board_ip, sizeof(board->ip)-1);
+    char *ifptr = fetch_ifname(board->sockfd, board->ifname, sizeof(board->ifname));
+    if(!ifptr) {
+        LL_PRINT("failed to retrieve interface name for board\n");
+        return 0;
+    }
+
+    if(!use_firewall()) {
+        LL_PRINT(\
+"WARNING: Unable to restrict other access to the hm2-eth device.\n"
+"This means that other software using the same network interface can violate\n"
+"realtime guarantees.  See hm2_eth(9) for more information.\n");
+    }
+
+    struct timeval timeout;
+    timeout.tv_sec = 0;
+    timeout.tv_usec = RECV_TIMEOUT_US;
+    ret = setsockopt(board->sockfd, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));
+    if (ret < 0) {
+        LL_PRINT("ERROR: can't set receive timeout socket option: %s\n", strerror(errno));
+        return -errno;
+    }
+
+    timeout.tv_sec = 0;
+    timeout.tv_usec = SEND_TIMEOUT_US;
+    ret = setsockopt(board->sockfd, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout));
+    if (ret < 0) {
+        LL_PRINT("ERROR: can't set send timeout socket option: %s\n", strerror(errno));
+        return -errno;
+    }
+
+    memset(&board->req, 0, sizeof(board->req));
+    struct sockaddr_in *sin;
+
+    sin = (struct sockaddr_in *) &board->req.arp_pa;
+    sin->sin_family = AF_INET;
+    sin->sin_addr.s_addr = inet_addr(board_ip);
+
+    board->req.arp_ha.sa_family = AF_LOCAL;
+    board->req.arp_flags = ATF_PERM | ATF_COM;
+    ret = fetch_hwaddr( board, (void*)&board->req.arp_ha.sa_data );
+    if(ret < 0) {
+        LL_PRINT("ERROR: Could not retrieve hardware address (MAC) of %s: %s\n", board_ip, strerror(-ret));
+        return ret;
+    }
+
+    // Pinning the ARP entry needs CAP_NET_ADMIN; rootless without setcap
+    // fails with EPERM.  Best-effort, not fatal: fall back to dynamic ARP
+    // so the board still loads.  Clear ATF_PERM so the SIOCDARP teardown
+    // in close_board() does not try to remove an entry we never set.
+    ret = ioctl(board->sockfd, SIOCSARP, &board->req);
+    if(ret < 0) {
+        LL_PRINT("WARNING: ioctl SIOCSARP failed: %s; continuing with "
+                 "dynamic ARP.  Install file capabilities (sudo make "
+                 "setcap) or run setuid to pin the board's ARP entry and "
+                 "avoid occasional transmit latency.\n", strerror(errno));
+        board->req.arp_flags &= ~ATF_PERM;
+    }
+
+    // install_firewall_board() is a no-op when no firewall backend is
+    // available (rootless install without CAP_NET_ADMIN, or
+    // firewall=none), so it is safe to call unconditionally.
+    ret = install_firewall_board(board->sockfd);
+    if(ret < 0) return ret;
+
+    board->write_packet_ptr = board->write_packet;
+    board->read_packet_ptr = board->read_packet;
+
+    return 0;
+}
+
+int init_board_realtime(hm2_eth_t *board){
+    (void)board;
+    return 0; //Nothing todo
+}
+
+int close_board(hm2_eth_t *board) {
+    int ret;
+    board->llio.reset(&board->llio);
+
+    clear_firewall();
+
+    if(board->req.arp_flags & ATF_PERM) {
+        ret = ioctl(board->sockfd, SIOCDARP, &board->req);
+        if(ret < 0) perror("ioctl SIOCDARP");
+    }
+    ret = shutdown(board->sockfd, SHUT_RDWR);
+    if (ret == -1)
+        LL_PRINT("ERROR: can't shutdown socket: %s\n", strerror(errno));
+    
+    ret = close(board->sockfd);
+    if (ret == -1)
+        LL_PRINT("ERROR: can't close socket: %s\n", strerror(errno));
+    
+    return ret < 0 ? -errno : 0;
+}
+
+int eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags) {
+    return send(board->sockfd, buffer, len, flags);
+}
+
+int eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags) {
+    return recv(board->sockfd, buffer, len, flags);
+}
+
+int eth_socket_recv_loop(hm2_eth_t *board, void *buffer, int len, int flags, long timeout) {
+    long long end = rtapi_get_time() + timeout;
+    int result;
+    do {
+        result = eth_socket_recv(board, buffer, len, flags);
+    } while(result < 0 && rtapi_get_time() < end);
+    return result;
+}
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net.h b/src/hal/drivers/mesa-hostmot2/hm2_eth_net.h
new file mode 100644
index 00000000000..ddfcd68fc4c
--- /dev/null
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net.h
@@ -0,0 +1,40 @@
+/*    This is a component of LinuxCNC
+ *    Copyright 2013,2014 Michael Geszkiewicz <micges@wp.pl>,
+ *    Jeff Epler <jepler@unpythonic.net>
+ *
+ *    This program is free software; you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation; either version 2 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef __INCLUDE_HM2_ETH_NET_H
+#define __INCLUDE_HM2_ETH_NET_H
+
+#include "hm2_eth.h"
+
+//We use the linker to define the module name
+//It must match the .so file
+extern char* HM2_LLIO_MODULE_NAME;
+
+int init_board(hm2_eth_t *board, const char *board_ip);
+int init_board_realtime(hm2_eth_t *board);
+int close_board(hm2_eth_t *board);
+int eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags);
+int eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags);
+int eth_socket_recv_loop(hm2_eth_t *board, void *buffer, int len, int flags, long timeout);
+
+#define UDP_PORT 27181
+#define SEND_TIMEOUT_US 10
+#define RECV_TIMEOUT_US 10
+
+#endif
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
new file mode 100644
index 00000000000..f6c3dddcb3c
--- /dev/null
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
@@ -0,0 +1,313 @@
+/*    This is a component of LinuxCNC
+ *    Copyright 2013,2014 Michael Geszkiewicz <micges@wp.pl>,
+ *    Jeff Epler <jepler@unpythonic.net>
+ *
+ *    EVL Port:
+ *    Copyright 2024 Hannes Diethelm <hannes.diethelm@gmail.com>
+ *
+ *    This program is free software; you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation; either version 2 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <sys/fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <net/if_arp.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/fsuid.h>
+
+#include <evl/thread.h>
+#include <evl/clock.h>
+#include <evl/net/net.h>
+
+#include <rtapi.h>
+#include <rtapi_string.h>
+
+#include "hostmot2-lowlevel.h"
+#include "hm2_eth_net.h"
+
+char* HM2_LLIO_MODULE_NAME="hm2_eth_evl";
+
+/// ethernet io functions
+
+int oob_enable_port(hm2_eth_t *board);
+int oob_disable_port(hm2_eth_t *board);
+
+int init_board(hm2_eth_t *board, const char *board_ip) {
+    int ret;
+    LL_PRINT("%s: INFO: init board (Xenomai EVL)\n", board_ip);
+    board->is_evl_oob_active = false;
+    board->sockfd = socket(PF_INET, SOCK_DGRAM | SOCK_OOB, IPPROTO_IP);
+    if (board->sockfd < 0) {
+        LL_PRINT("ERROR: can't open socket: %s\n", strerror(errno));
+        return -errno;
+    }
+
+    board->server_addr.sin_family = AF_INET;
+    board->server_addr.sin_port = htons(LBP16_UDP_PORT);
+    board->server_addr.sin_addr.s_addr = inet_addr(board_ip);
+
+    board->local_addr.sin_family      = AF_INET;
+    board->local_addr.sin_addr.s_addr = INADDR_ANY;
+
+    ret = connect(board->sockfd, (struct sockaddr *) &board->server_addr, sizeof(struct sockaddr_in));
+    if (ret < 0) {
+        LL_PRINT("ERROR: can't connect: %s\n", strerror(errno));
+        return -errno;
+    }
+
+    strncpy(board->ip, board_ip, sizeof(board->ip)-1);
+    char *ifptr = fetch_ifname(board->sockfd, board->ifname, sizeof(board->ifname));
+    if(!ifptr) {
+        LL_PRINT("failed to retrieve interface name for board\n");
+        return 0;
+    }
+
+    if (setsockopt(board->sockfd, SOL_SOCKET, SO_BINDTODEVICE, board->ifname, strlen(board->ifname))){
+        LL_PRINT("ERROR: can't SO_BINDTODEVICE socket: %s\n", strerror(errno));
+    }
+
+    if(!use_firewall()) {
+        LL_PRINT(\
+"WARNING: Unable to restrict other access to the hm2-eth device.\n"
+"This means that other software using the same network interface can violate\n"
+"realtime guarantees.  See hm2_eth(9) for more information.\n");
+    }
+
+    struct timeval timeout;
+    timeout.tv_sec = 0;
+    timeout.tv_usec = RECV_TIMEOUT_US;
+    ret = setsockopt(board->sockfd, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));
+    if (ret < 0) {
+        LL_PRINT("ERROR: can't set receive timeout socket option: %s\n", strerror(errno));
+        return -errno;
+    }
+
+    timeout.tv_sec = 0;
+    timeout.tv_usec = SEND_TIMEOUT_US;
+    ret = setsockopt(board->sockfd, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout));
+    if (ret < 0) {
+        LL_PRINT("ERROR: can't set send timeout socket option: %s\n", strerror(errno));
+        return -errno;
+    }
+
+    memset(&board->req, 0, sizeof(board->req));
+    struct sockaddr_in *sin;
+
+    sin = (struct sockaddr_in *) &board->req.arp_pa;
+    sin->sin_family = AF_INET;
+    sin->sin_addr.s_addr = inet_addr(board_ip);
+
+    board->req.arp_ha.sa_family = AF_LOCAL;
+    board->req.arp_flags = ATF_PERM | ATF_COM;
+    ret = fetch_hwaddr( board, (void*)&board->req.arp_ha.sa_data );
+    if(ret < 0) {
+        LL_PRINT("ERROR: Could not retrieve hardware address (MAC) of %s: %s\n", board_ip, strerror(-ret));
+        return ret;
+    }
+
+    // install_firewall_board() is a no-op when no firewall backend is
+    // available (rootless install without CAP_NET_ADMIN, or
+    // firewall=none), so it is safe to call unconditionally.
+    ret = install_firewall_board(board->sockfd);
+    if(ret < 0) return ret;
+
+    board->write_packet_ptr = board->write_packet;
+    board->read_packet_ptr = board->read_packet;
+
+    return 0;
+}
+
+int init_board_realtime(hm2_eth_t *board){
+    return oob_enable_port(board);
+}
+
+int oob_enable_port(hm2_eth_t *board){
+    //long long t1, t2;
+    int devfd, ret;
+    
+    LL_PRINT("%s: INFO: enable OOB for board on if %s\n", board->ip, board->ifname);
+
+    //t1 = rtapi_get_time();
+    size_t poolsz = 0, bufsz = 0; /* Use defaults. */
+
+    //Need root fsuid for this
+    uid_t previous = setfsuid(0);
+
+    devfd = evl_net_open_dev(board->ifname);
+    if (devfd < 0){
+        LL_PRINT("ERROR: cannot open out-of-band port %s\n", board->ifname);
+        return -1;
+    }
+
+    ret = evl_net_enable_port(devfd, poolsz, bufsz);
+    if (ret){
+        LL_PRINT("ERROR: cannot enable out-of-band port on %s\n", board->ifname);
+        return -1;
+    }
+
+    close(devfd);    /* We don't need the fildes of the oob port. */
+    
+    ret = evl_net_solicit(board->sockfd, (struct sockaddr*)&board->server_addr, EVL_NEIGH_PERMANENT);
+    if (ret){
+        LL_PRINT("solicit did not respond\n");
+        return -1;
+    }
+
+    setfsuid(previous);
+
+    /*t2 = rtapi_get_time();
+    LL_PRINT("Enable dur = %lli\n", t2-t1);*/
+
+    board->is_evl_oob_active=true;
+
+    return 0;
+}
+
+int disable_oob_port(hm2_eth_t *board)
+{
+    (void)board;
+    int ret, devfd;
+
+    LL_PRINT("%s: INFO: disable OOB for board on if %s\n", board->ip, board->ifname);
+
+    //Need root fsuid for this
+    uid_t previous = setfsuid(0);
+
+    devfd = evl_net_open_dev(board->ifname);
+    if (devfd < 0){
+        LL_PRINT("ERROR: cannot open out-of-band port %s\n", board->ifname);
+        return -1;
+    }
+
+    ret = evl_net_disable_port(devfd);
+    if (ret < 0){
+        LL_PRINT("ERROR: cannot disable out-of-band port on %s\n", board->ifname);
+        return -1;
+    }
+
+    close(devfd);
+
+    setfsuid(previous);
+
+    board->is_evl_oob_active=false;
+
+    return 0;
+}
+
+int close_board(hm2_eth_t *board) {
+    int ret;
+    disable_oob_port(board);
+
+    board->llio.reset(&board->llio);
+
+    clear_firewall();
+
+    ret = close(board->sockfd);
+    if (ret == -1)
+        LL_PRINT("ERROR: can't close socket: %s\n", strerror(errno));
+    
+    return ret < 0 ? -errno : 0;
+}
+/*
+static void print_addr(char* desc, struct sockaddr_in *addr){
+    char ip_str[INET_ADDRSTRLEN+1];
+    inet_ntop(AF_INET, &(addr->sin_addr), ip_str, sizeof(ip_str));
+    LL_PRINT("--------%s--------\n", desc);
+    LL_PRINT("IP-Address: %s\n", ip_str);
+    LL_PRINT("Port:       %d\n", ntohs(addr->sin_port));
+    LL_PRINT("Family:     %d\n", ntohs(addr->sin_family));
+}
+*/
+
+int eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags){
+    ssize_t ret = 0;
+    if(board->is_evl_oob_active){
+        struct iovec iov;
+        struct oob_msghdr msghdr;
+        struct timespec ts_timeout;
+
+        evl_read_clock(EVL_CLOCK_MONOTONIC, &ts_timeout);
+        ts_timeout.tv_nsec += 1000*1000;
+        while(ts_timeout.tv_nsec >= 1000000000){
+            ts_timeout.tv_nsec -= 1000000000;
+            ts_timeout.tv_sec ++;
+        }
+
+        /* OUTPUT */
+        iov.iov_base = (void *)buffer;
+        iov.iov_len = len;
+        msghdr.msg_iov = &iov;
+        msghdr.msg_iovlen = 1;
+        msghdr.msg_control = NULL;
+        msghdr.msg_controllen = 0;
+        msghdr.msg_name = &board->server_addr;
+        msghdr.msg_namelen = sizeof(board->server_addr);
+        /*msghdr.msg_name = NULL;
+        msghdr.msg_namelen = 0;*/
+        msghdr.msg_flags = 0;
+        ret = oob_sendmsg(board->sockfd, &msghdr, &ts_timeout, flags);
+        if(ret == -1){
+            LL_PRINT("ERROR: oob_sendmsg %m %i %li\n", errno, ret);
+        }
+    }else{
+        ret = send(board->sockfd, buffer, len, flags);
+    }
+    return ret;
+}
+
+int eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags){
+    ssize_t ret = 0;
+    if(board->is_evl_oob_active){
+        struct oob_msghdr msghdr;
+        struct iovec iov;
+        struct timespec ts_timeout;
+
+        evl_read_clock(EVL_CLOCK_MONOTONIC, &ts_timeout);
+        ts_timeout.tv_nsec += 1000*1000;
+        while(ts_timeout.tv_nsec >= 1000000000){
+            ts_timeout.tv_nsec -= 1000000000;
+            ts_timeout.tv_sec ++;
+        }
+
+        /* INPUT */
+        iov.iov_base = buffer;
+        iov.iov_len = len;
+        msghdr.msg_iov = &iov;
+        msghdr.msg_iovlen = 1;
+        msghdr.msg_control = NULL;
+        msghdr.msg_controllen = 0;
+        msghdr.msg_name = &board->local_addr;
+        msghdr.msg_namelen = sizeof(board->local_addr);
+        /*msghdr.msg_name = NULL;
+        msghdr.msg_namelen = 0;*/
+        msghdr.msg_flags = 0;
+        ret = oob_recvmsg(board->sockfd, &msghdr, &ts_timeout, flags);
+    }else{
+        ret = recv(board->sockfd, buffer, len, flags);
+    }
+    return ret;
+}
+
+int eth_socket_recv_loop(hm2_eth_t *board, void *buffer, int len, int flags, long timeout) {
+    long long end = rtapi_get_time() + timeout;
+    int result;
+    do {
+        result = eth_socket_recv(board, buffer, len, flags);
+    } while(result < 0 && rtapi_get_time() < end);
+    return result;
+}

From 56d4a1532b6547138ad6e2173617d8e085f7fce9 Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Mon, 29 Jun 2026 23:52:26 +0200
Subject: [PATCH 3/5] Xenomai EVL network for Hostmot2: Single component

Change back to one component that uses a "board_rtnet" argument to switch
between the types
---
 src/Makefile                                  | 15 ++--
 src/configure.ac                              |  2 +-
 src/hal/drivers/mesa-hostmot2/hm2_eth.c       | 69 ++++++++++++++++++-
 src/hal/drivers/mesa-hostmot2/hm2_eth.h       | 14 +++-
 .../drivers/mesa-hostmot2/hm2_eth_net_evl.c   | 23 ++-----
 .../{hm2_eth_net.h => hm2_eth_net_evl.h}      | 22 +++---
 .../{hm2_eth_net.c => hm2_eth_net_posix.c}    | 23 ++-----
 .../drivers/mesa-hostmot2/hm2_eth_net_posix.h | 35 ++++++++++
 8 files changed, 141 insertions(+), 62 deletions(-)
 rename src/hal/drivers/mesa-hostmot2/{hm2_eth_net.h => hm2_eth_net_evl.h} (64%)
 rename src/hal/drivers/mesa-hostmot2/{hm2_eth_net.c => hm2_eth_net_posix.c} (89%)
 create mode 100644 src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.h

diff --git a/src/Makefile b/src/Makefile
index 6ddb0f28e70..f43362f943b 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1004,9 +1004,6 @@ obj-$(CONFIG_HOSTMOT2) += hostmot2.o hm2_test.o hm2_pci.o hm2_7i43.o hm2_7i90.o
 obj-$(CONFIG_HOSTMOT2) += hm2_modbus.o
 ifeq ($(BUILD_SYS),uspace)
 obj-$(CONFIG_HOSTMOT2) += hm2_eth.o
-ifeq ($(CONFIG_USPACE_XENOMAI_EVL),y)
-obj-$(CONFIG_HOSTMOT2) += hm2_eth_evl.o
-endif
 obj-$(CONFIG_HOSTMOT2) += hm2_spi.o hm2_rpspi.o hm2_spix.o
 endif
 hostmot2-objs :=			  \
@@ -1052,12 +1049,11 @@ hm2_pci-objs  :=			  \
     $(MATHSTUB)
 hm2_eth-objs  :=			  \
     hal/drivers/mesa-hostmot2/hm2_eth.o   \
-    hal/drivers/mesa-hostmot2/hm2_eth_net.o   \
-    $(MATHSTUB)
-hm2_eth_evl-objs  :=			  \
-    hal/drivers/mesa-hostmot2/hm2_eth.o   \
-    hal/drivers/mesa-hostmot2/hm2_eth_net_evl.o   \
-    $(MATHSTUB)
+    hal/drivers/mesa-hostmot2/hm2_eth_net_posix.o
+ifeq ($(CONFIG_USPACE_XENOMAI_EVL),y)
+hm2_eth-objs  += hal/drivers/mesa-hostmot2/hm2_eth_net_evl.o
+endif
+hm2_eth-objs  += $(MATHSTUB)
 hm2_spi-objs  :=			  \
     hal/drivers/mesa-hostmot2/hm2_spi.o   \
     hal/drivers/mesa-hostmot2/llio_info.o \
@@ -1405,7 +1401,6 @@ endif
 ../rtlib/hal_parport$(MODULE_EXT): $(addprefix objects/rt,$(hal_parport-objs))
 ../rtlib/hal_ppmc$(MODULE_EXT): $(addprefix objects/rt,$(hal_ppmc-objs))
 ../rtlib/hm2_eth$(MODULE_EXT): $(addprefix objects/rt,$(hm2_eth-objs))
-../rtlib/hm2_eth_evl$(MODULE_EXT): $(addprefix objects/rt,$(hm2_eth_evl-objs))
 ../rtlib/hm2_spi$(MODULE_EXT): $(addprefix objects/rt,$(hm2_spi-objs))
 ../rtlib/hm2_rpspi$(MODULE_EXT): $(addprefix objects/rt,$(hm2_rpspi-objs))
 ../rtlib/hm2_spix$(MODULE_EXT): $(addprefix objects/rt,$(hm2_spix-objs))
diff --git a/src/configure.ac b/src/configure.ac
index 15054b93100..5caef02058d 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -264,7 +264,7 @@ if test "$RTS" = uspace || test -z "$RTS" -a "$RTAI_CONFIG" = "none" ; then
     CONFIG_USPACE_XENOMAI_EVL=y
     XENOMAI_EVL_CFLAGS=
     XENOMAI_EVL_LDFLAGS=-levl
-    AC_DEFINE([USPACE_XENOMAI_EVL], [], [Define if uspace realtime should optionally support Xenomai-evl])
+    AC_DEFINE([USPACE_XENOMAI_EVL], [], [Define if uspace realtime should optionally support Xenomai EVL])
   fi
 
   AC_SUBST([CONFIG_USPACE_XENOMAI_EVL])
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.c b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
index 94bd4732457..e9291a8817b 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
@@ -43,10 +43,15 @@
 
 #include <hal.h>
 
+#include "config.h" //For USPACE_XENOMAI_EVL
+
 #include "hostmot2-lowlevel.h"
 #include "hostmot2.h"
 #include "hm2_eth.h"
-#include "hm2_eth_net.h"
+#include "hm2_eth_net_posix.h"
+#ifdef USPACE_XENOMAI_EVL
+#include "hm2_eth_net_evl.h"
+#endif
 
 struct kvlist {
     struct rtapi_list_head list;
@@ -90,6 +95,9 @@ MODULE_SUPPORTED_DEVICE("Mesa-AnythingIO-7i80");
 static char *board_ip[MAX_ETH_BOARDS];
 RTAPI_MP_ARRAY_STRING(board_ip, MAX_ETH_BOARDS, "ip address of ethernet board(s)");
 
+static char *board_rtnet[MAX_ETH_BOARDS];
+RTAPI_MP_ARRAY_STRING(board_rtnet, MAX_ETH_BOARDS, "realtime network type of ethernet board(s)");
+
 static char *config[MAX_ETH_BOARDS];
 RTAPI_MP_ARRAY_STRING(config, MAX_ETH_BOARDS, "config string for the AnyIO boards (see hostmot2(9) manpage)");
 
@@ -457,6 +465,9 @@ static const char *hm2_8cSS_pin_names[] = {
 
 static hm2_eth_t boards[MAX_ETH_BOARDS]={};
 
+static int eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags);
+static int eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags);
+
 /// firewall functions
 
 // hm2_eth installs firewall rules to isolate the dedicated Mesa
@@ -805,6 +816,58 @@ int fetch_hwaddr(hm2_eth_t *board, unsigned char buf[6]) {
     return 0;
 }
 
+/// ethernet io functions mapping
+static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_rtnet){
+    //Default (NULL) is posix
+    if(board_rtnet == NULL || strcmp(board_rtnet, "posix") == 0){
+        board->init_board = &hm2_posix_init_board;
+        board->init_board_realtime = &hm2_posix_init_board_realtime;
+        board->close_board = &hm2_posix_close_board;
+        board->eth_socket_send = &hm2_posix_eth_socket_send;
+        board->eth_socket_recv = &hm2_posix_eth_socket_recv;
+    } else if (strcmp(board_rtnet, "evl") == 0) {
+#ifdef USPACE_XENOMAI_EVL
+        board->init_board = &hm2_evl_init_board;
+        board->init_board_realtime = &hm2_evl_init_board_realtime;
+        board->close_board = &hm2_evl_close_board;
+        board->eth_socket_send = &hm2_evl_eth_socket_send;
+        board->eth_socket_recv = &hm2_evl_eth_socket_recv;
+#else
+        LL_PRINT("ERROR: board_rtnet = %s not available, LinuxCNC was built without Xenomai EVL support\n", board_rtnet)
+#endif
+    } else {
+        LL_PRINT("ERROR: board_rtnet = %s undefined\n", board_rtnet)
+        return -1;
+    }
+
+    return board->init_board(board, board_ip);
+}
+
+static inline int init_board_realtime(hm2_eth_t *board){
+    return board->init_board_realtime(board);
+}
+
+static inline int close_board(hm2_eth_t *board){
+    return board->close_board(board);
+}
+
+static inline int eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags){
+    return board->eth_socket_send(board, buffer, len, flags);
+}
+
+static inline int eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags){
+    return board->eth_socket_recv(board, buffer, len, flags);
+}
+
+int eth_socket_recv_loop(hm2_eth_t *board, void *buffer, int len, int flags, long timeout) {
+    long long end = rtapi_get_time() + timeout;
+    int result;
+    do {
+        result = eth_socket_recv(board, buffer, len, flags);
+    } while(result < 0 && rtapi_get_time() < end);
+    return result;
+}
+
 /// hm2_eth io functions
 
 static int hm2_eth_read(hm2_lowlevel_io_t *this, rtapi_u32 addr, void *buffer, int size) {
@@ -1598,7 +1661,7 @@ int rtapi_app_main(void) {
 
     LL_PRINT("loading Mesa AnyIO HostMot2 ethernet driver version " HM2_ETH_VERSION "\n");
 
-    ret = hal_init(HM2_LLIO_MODULE_NAME);
+    ret = hal_init(HM2_LLIO_NAME);
     if (ret < 0)
         return ret;
     comp_id = ret;
@@ -1606,7 +1669,7 @@ int rtapi_app_main(void) {
     clear_firewall();
 
     for(i = 0, ret = 0; ret == 0 && i<MAX_ETH_BOARDS && board_ip[i] && *board_ip[i]; i++) {
-        ret = init_board(&boards[i], board_ip[i]);
+        ret = init_board(&boards[i], board_ip[i], board_rtnet[i]);
         if(ret < 0) board_ip[i] = 0;
     }
 
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.h b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
index 69a3a07218d..e5e3ff89cba 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.h
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.h
@@ -35,7 +35,9 @@ typedef struct {
     int from;
 } hm2_read_queue_entry_t;
 
-typedef struct {
+typedef struct hm2_eth_t hm2_eth_t;
+
+struct hm2_eth_t {
     hm2_lowlevel_io_t llio;
 
     int sockfd;
@@ -44,6 +46,14 @@ typedef struct {
 
     char ip[64];
     char ifname[64];
+
+    //RT network specific functions
+    int (*init_board)(hm2_eth_t *board, const char *board_ip);
+    int (*init_board_realtime)(hm2_eth_t *board);
+    int (*close_board)(hm2_eth_t *board);
+    int (*eth_socket_send)(hm2_eth_t *board, const void *buffer, int len, int flags);
+    int (*eth_socket_recv)(hm2_eth_t *board, void *buffer, int len, int flags);
+
     //Only for evl implementation
     bool is_evl_oob_active;
 
@@ -75,7 +85,7 @@ typedef struct {
         hal_s32_t *packet_error_level;
         hal_bit_t *packet_error_exceeded;
     } *hal;
-} hm2_eth_t;
+};
 
 bool use_firewall();
 int install_firewall_board(int sockfd);
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
index f6c3dddcb3c..04b692b7005 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.c
@@ -38,16 +38,14 @@
 #include <rtapi_string.h>
 
 #include "hostmot2-lowlevel.h"
-#include "hm2_eth_net.h"
-
-char* HM2_LLIO_MODULE_NAME="hm2_eth_evl";
+#include "hm2_eth_net_evl.h"
 
 /// ethernet io functions
 
 int oob_enable_port(hm2_eth_t *board);
 int oob_disable_port(hm2_eth_t *board);
 
-int init_board(hm2_eth_t *board, const char *board_ip) {
+int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip) {
     int ret;
     LL_PRINT("%s: INFO: init board (Xenomai EVL)\n", board_ip);
     board->is_evl_oob_active = false;
@@ -132,7 +130,7 @@ int init_board(hm2_eth_t *board, const char *board_ip) {
     return 0;
 }
 
-int init_board_realtime(hm2_eth_t *board){
+int hm2_evl_init_board_realtime(hm2_eth_t *board){
     return oob_enable_port(board);
 }
 
@@ -209,7 +207,7 @@ int disable_oob_port(hm2_eth_t *board)
     return 0;
 }
 
-int close_board(hm2_eth_t *board) {
+int hm2_evl_close_board(hm2_eth_t *board) {
     int ret;
     disable_oob_port(board);
 
@@ -234,7 +232,7 @@ static void print_addr(char* desc, struct sockaddr_in *addr){
 }
 */
 
-int eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags){
+int hm2_evl_eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags){
     ssize_t ret = 0;
     if(board->is_evl_oob_active){
         struct iovec iov;
@@ -270,7 +268,7 @@ int eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags){
     return ret;
 }
 
-int eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags){
+int hm2_evl_eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags){
     ssize_t ret = 0;
     if(board->is_evl_oob_active){
         struct oob_msghdr msghdr;
@@ -302,12 +300,3 @@ int eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags){
     }
     return ret;
 }
-
-int eth_socket_recv_loop(hm2_eth_t *board, void *buffer, int len, int flags, long timeout) {
-    long long end = rtapi_get_time() + timeout;
-    int result;
-    do {
-        result = eth_socket_recv(board, buffer, len, flags);
-    } while(result < 0 && rtapi_get_time() < end);
-    return result;
-}
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net.h b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.h
similarity index 64%
rename from src/hal/drivers/mesa-hostmot2/hm2_eth_net.h
rename to src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.h
index ddfcd68fc4c..33b8113d2f0 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net.h
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_evl.h
@@ -2,6 +2,9 @@
  *    Copyright 2013,2014 Michael Geszkiewicz <micges@wp.pl>,
  *    Jeff Epler <jepler@unpythonic.net>
  *
+ *    EVL Port:
+ *    Copyright 2024 Hannes Diethelm <hannes.diethelm@gmail.com>
+ *
  *    This program is free software; you can redistribute it and/or modify
  *    it under the terms of the GNU General Public License as published by
  *    the Free Software Foundation; either version 2 of the License, or
@@ -17,21 +20,16 @@
  *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#ifndef __INCLUDE_HM2_ETH_NET_H
-#define __INCLUDE_HM2_ETH_NET_H
+#ifndef __INCLUDE_HM2_ETH_NET_EVL_H
+#define __INCLUDE_HM2_ETH_NET_EVL_H
 
 #include "hm2_eth.h"
 
-//We use the linker to define the module name
-//It must match the .so file
-extern char* HM2_LLIO_MODULE_NAME;
-
-int init_board(hm2_eth_t *board, const char *board_ip);
-int init_board_realtime(hm2_eth_t *board);
-int close_board(hm2_eth_t *board);
-int eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags);
-int eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags);
-int eth_socket_recv_loop(hm2_eth_t *board, void *buffer, int len, int flags, long timeout);
+int hm2_evl_init_board(hm2_eth_t *board, const char *board_ip);
+int hm2_evl_init_board_realtime(hm2_eth_t *board);
+int hm2_evl_close_board(hm2_eth_t *board);
+int hm2_evl_eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags);
+int hm2_evl_eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags);
 
 #define UDP_PORT 27181
 #define SEND_TIMEOUT_US 10
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net.c b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
similarity index 89%
rename from src/hal/drivers/mesa-hostmot2/hm2_eth_net.c
rename to src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
index ad0a7fbcc7f..6ce8919e876 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth_net.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.c
@@ -30,13 +30,11 @@
 #include <rtapi_string.h>
 
 #include "hostmot2-lowlevel.h"
-#include "hm2_eth_net.h"
-
-char* HM2_LLIO_MODULE_NAME="hm2_eth";
+#include "hm2_eth_net_posix.h"
 
 /// ethernet io functions
 
-int init_board(hm2_eth_t *board, const char *board_ip) {
+int hm2_posix_init_board(hm2_eth_t *board, const char *board_ip) {
     int ret;
     LL_PRINT("%s: INFO: init board (POSIX)\n", board_ip);
     board->sockfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
@@ -129,12 +127,12 @@ int init_board(hm2_eth_t *board, const char *board_ip) {
     return 0;
 }
 
-int init_board_realtime(hm2_eth_t *board){
+int hm2_posix_init_board_realtime(hm2_eth_t *board){
     (void)board;
     return 0; //Nothing todo
 }
 
-int close_board(hm2_eth_t *board) {
+int hm2_posix_close_board(hm2_eth_t *board) {
     int ret;
     board->llio.reset(&board->llio);
 
@@ -155,19 +153,10 @@ int close_board(hm2_eth_t *board) {
     return ret < 0 ? -errno : 0;
 }
 
-int eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags) {
+int hm2_posix_eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags) {
     return send(board->sockfd, buffer, len, flags);
 }
 
-int eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags) {
+int hm2_posix_eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags) {
     return recv(board->sockfd, buffer, len, flags);
 }
-
-int eth_socket_recv_loop(hm2_eth_t *board, void *buffer, int len, int flags, long timeout) {
-    long long end = rtapi_get_time() + timeout;
-    int result;
-    do {
-        result = eth_socket_recv(board, buffer, len, flags);
-    } while(result < 0 && rtapi_get_time() < end);
-    return result;
-}
diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.h b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.h
new file mode 100644
index 00000000000..0aa04cfac2a
--- /dev/null
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth_net_posix.h
@@ -0,0 +1,35 @@
+/*    This is a component of LinuxCNC
+ *    Copyright 2013,2014 Michael Geszkiewicz <micges@wp.pl>,
+ *    Jeff Epler <jepler@unpythonic.net>
+ *
+ *    This program is free software; you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation; either version 2 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef __INCLUDE_HM2_ETH_NET_POSIX_H
+#define __INCLUDE_HM2_ETH_NET_POSIX_H
+
+#include "hm2_eth.h"
+
+int hm2_posix_init_board(hm2_eth_t *board, const char *board_ip);
+int hm2_posix_init_board_realtime(hm2_eth_t *board);
+int hm2_posix_close_board(hm2_eth_t *board);
+int hm2_posix_eth_socket_send(hm2_eth_t *board, const void *buffer, int len, int flags);
+int hm2_posix_eth_socket_recv(hm2_eth_t *board, void *buffer, int len, int flags);
+
+#define UDP_PORT 27181
+#define SEND_TIMEOUT_US 10
+#define RECV_TIMEOUT_US 10
+
+#endif

From 510076f10eb6bab5741da42e39e7cabd2425cf8d Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Tue, 30 Jun 2026 12:04:57 +0200
Subject: [PATCH 4/5] hal_lib: Add missing EXPORT_SYMBOL(hal_get_realtime_type)

---
 src/hal/hal_lib.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/hal/hal_lib.c b/src/hal/hal_lib.c
index 162f9451565..1d1c7639364 100644
--- a/src/hal/hal_lib.c
+++ b/src/hal/hal_lib.c
@@ -4692,6 +4692,7 @@ EXPORT_SYMBOL(hal_set_unready);
 EXPORT_SYMBOL(hal_exit);
 EXPORT_SYMBOL(hal_malloc);
 EXPORT_SYMBOL(hal_comp_name);
+EXPORT_SYMBOL(hal_get_realtime_type);
 
 EXPORT_SYMBOL(hal_pin_bit_new);
 EXPORT_SYMBOL(hal_pin_float_new);

From 07a66839e91d8a748a4335ebc1f3ba187e57f5be Mon Sep 17 00:00:00 2001
From: Hannes Diethelm <hannes.diethelm@gmail.com>
Date: Tue, 30 Jun 2026 12:07:37 +0200
Subject: [PATCH 5/5] Xenomai EVL network for Hostmot2: Check for EVL running

---
 src/hal/drivers/mesa-hostmot2/hm2_eth.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/hal/drivers/mesa-hostmot2/hm2_eth.c b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
index e9291a8817b..4c363b5fca6 100644
--- a/src/hal/drivers/mesa-hostmot2/hm2_eth.c
+++ b/src/hal/drivers/mesa-hostmot2/hm2_eth.c
@@ -819,7 +819,7 @@ int fetch_hwaddr(hm2_eth_t *board, unsigned char buf[6]) {
 /// ethernet io functions mapping
 static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_rtnet){
     //Default (NULL) is posix
-    if(board_rtnet == NULL || strcmp(board_rtnet, "posix") == 0){
+    if (board_rtnet == NULL || strcmp(board_rtnet, "posix") == 0) {
         board->init_board = &hm2_posix_init_board;
         board->init_board_realtime = &hm2_posix_init_board_realtime;
         board->close_board = &hm2_posix_close_board;
@@ -827,6 +827,9 @@ static int init_board(hm2_eth_t *board, const char *board_ip, const char *board_
         board->eth_socket_recv = &hm2_posix_eth_socket_recv;
     } else if (strcmp(board_rtnet, "evl") == 0) {
 #ifdef USPACE_XENOMAI_EVL
+        if (hal_get_realtime_type() != REALTIME_TYPE_XENOMAI_EVL) {
+            LL_PRINT("ERROR: board_rtnet = %s not available, LinuxCNC not running with Xenomai4 EVL realtime\n", board_rtnet)
+        }
         board->init_board = &hm2_evl_init_board;
         board->init_board_realtime = &hm2_evl_init_board_realtime;
         board->close_board = &hm2_evl_close_board;