kernel: net: Implement IEEE 802.3 + ARP requestsmain

Introduce IEEE 802.3 related headers such as ones containing the
structure of an ethernet frame as well as its types. This commit
additionally introduces ARP request logic.

Signed-off-by: Ian Moffett <ian@osmora.org>

4 files changed, 227 insertions, 36 deletions

diff --git a/sys/include/net/ethertypes.h b/sys/include/net/ethertypes.h
new file mode 100644
index 0000000..753ea10
--- /dev/null
+++ b/sys/include/net/ethertypes.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _NET_ETHERTYPES_H_
+#define _NET_ETHERTYPES_H_
+
+#define ETHERTYPE_IPV4   0x0800
+#define ETHERTYPE_ARP    0x0806
+
+#endif  /* !_NET_ETHERTYPES_H_ */
diff --git a/sys/include/net/if_arp.h b/sys/include/net/if_arp.h
new file mode 100644
index 0000000..cbfb2fe
--- /dev/null
+++ b/sys/include/net/if_arp.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _NETINET_IF_ARP_H_
+#define _NETINET_IF_ARP_H_
+
+#include <sys/types.h>
+#include <net/ethertypes.h>
+
+/* ARP hardware types */
+#define ARP_HWTYPE_ETHER 1
+
+/* ARP operation types */
+#define ARP_REQUEST 1
+#define ARP_REPLY   2
+
+struct arp_hdr {
+    uint16_t hw_type;      /* See ARP_HWTYPE_*  */
+    uint16_t proto_type;   /* See ETHERTYPE_*  */
+    uint8_t hw_len;        /* See ETHER_ADDR_LEN */
+    uint8_t proto_len;     /* Protocol address length */
+    uint16_t op_type;      /* See operation types above */
+};
+
+#endif  /* !_NETINET_IF_ARP_H_ */
diff --git a/sys/include/net/if_ether.h b/sys/include/netinet/if_ether.h
index a8fcfa5..571622d 100644
--- a/sys/include/net/if_ether.h
+++ b/sys/include/netinet/if_ether.h
@@ -27,48 +27,29 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef _IF_ETHER_H_
-#define _IF_ETHER_H_
+#ifndef _NETINET_IF_ETHER_H_
+#define _NETINET_IF_ETHER_H_
 
-#include <sys/cdefs.h>
 #include <sys/types.h>
-#include <net/if.h>
+#include <net/if_arp.h>
+#include <net/if_var.h>
 
-#define MACADDR_LEN 6
+#define ETHER_ADDR_LEN 6
 
-struct __packed ether_frame {
-    uint8_t sync[7];        /* Preamble (sync stuff) */
-    uint8_t spd;            /* Start frame delimiter */
-    uint8_t macd[6];        /* MAC destination */
-    uint8_t macs[6];        /* MAC source */
-    uint16_t type;          /* Protocol type */
-    char payload[1];        /* sized @ 1+n */
+struct ether_arp {
+    struct arp_hdr hdr;
+    uint8_t sha[ETHER_ADDR_LEN];
+    uint8_t spa[4];
+    uint8_t tha[ETHER_ADDR_LEN];
+    uint8_t tpa[4];
 };
 
-/*
- * Used by the driver to buffer packets.
- */
-struct etherbuf {
-    struct ether_frame *frp;
-    off_t head;
-    off_t tail;
-    size_t cap;     /* In entries */
+struct ether_frame {
+    uint8_t ether_daddr[ETHER_ADDR_LEN];
+    uint8_t ether_saddr[ETHER_ADDR_LEN];
+    uint16_t ether_type;
 };
 
-/*
- * Ethernet device
- *
- * if_ether: E
- * driver: D
- *
- * @if_name: Interface name.
- * @tx: Transmit packets (D->E)
- */
-struct etherdev {
-    char if_name[IFNAMESIZ];
-    struct etherbuf *buf;
-    ssize_t(*tx)(struct etherdev *ep, const void *buf, size_t len);
-    char mac_addr[MACADDR_LEN];
-};
+int arp_request(struct netif *nifp, uint8_t *sproto, uint8_t *tproto);
 
-#endif  /* !_IF_ETHER_H_ */
+#endif  /* !_NETINET_IF_ETHER_H_ */
diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c
new file mode 100644
index 0000000..0c458a4
--- /dev/null
+++ b/sys/netinet/if_ether.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/endian.h>
+#include <sys/errno.h>
+#include <vm/dynalloc.h>
+#include <net/ethertypes.h>
+#include <netinet/if_ether.h>
+#include <string.h>
+
+struct arp_pkt {
+    struct ether_frame ehfr;
+    struct ether_arp payload;
+};
+
+static void
+set_hwaddr(struct netif_addr *addrp, char addr[ETHER_ADDR_LEN])
+{
+    uint16_t *psrc, *p;
+
+    psrc = (uint16_t *)&addrp->data[0];
+    p = (uint16_t *)addr;
+
+    p[0] = swap16(psrc[0]);
+    p[1] = swap16(psrc[1]);
+    p[2] = swap16(psrc[2]);
+}
+
+static struct arp_pkt *
+arp_create(struct netif *nifp, uint32_t *sproto, uint32_t *tproto, uint16_t op)
+{
+    struct arp_pkt *packet;
+    struct arp_hdr *hdrp;
+    struct ether_frame *frp;
+    struct ether_arp *payload;
+
+    packet = dynalloc(sizeof(*packet));
+    if (packet == NULL) {
+        return NULL;
+    }
+
+    frp = &packet->ehfr;
+    payload = &packet->payload;
+    hdrp = &payload->hdr;
+
+    /* Ethernet frame, from source to all */
+    set_hwaddr(&nifp->addr, frp->ether_saddr);
+    memset(frp->ether_daddr, 0xFF, ETHER_ADDR_LEN);
+    frp->ether_type = swap16(ETHERTYPE_ARP);
+
+    /* Now for the ARP header */
+    hdrp->hw_type = swap16(ARP_HWTYPE_ETHER);
+    hdrp->proto_type = swap16(ETHERTYPE_IPV4);
+    hdrp->hw_len = ETHER_ADDR_LEN;
+    hdrp->proto_len = 4;
+    hdrp->op_type = swap16(op);
+
+    memcpy(payload->sha, frp->ether_saddr, ETHER_ADDR_LEN);
+    memset(payload->tha, 0xFF, ETHER_ADDR_LEN);
+
+    /* Protocol source address */
+    *((uint32_t *)payload->spa) = *sproto;
+    *((uint32_t *)payload->tpa) = *tproto;
+    return packet;
+}
+
+int
+arp_request(struct netif *nifp, uint8_t *sproto, uint8_t *tproto)
+{
+    struct arp_pkt *packet;
+    struct netbuf nb;
+    uint32_t *src_tmp, *targ_tmp;
+
+    if (nifp->tx_enq == NULL) {
+        return -ENOTSUP;
+    }
+    if (nifp->tx_start == NULL) {
+        return -ENOTSUP;
+    }
+
+    src_tmp = (uint32_t *)sproto;
+    targ_tmp = (uint32_t *)tproto;
+
+    packet = arp_create(nifp, src_tmp, targ_tmp, ARP_REQUEST);
+    if (packet == NULL) {
+        return -ENOMEM;
+    }
+
+    nb.len = sizeof(*packet);
+    memcpy(nb.data, packet, nb.len);
+
+    nifp->tx_enq(nifp, &nb, NULL);
+    nifp->tx_start(nifp);
+    dynfree(packet);
+    return 0;
+}