Meta: Move kernel and userland to their own folders.

This is to allow both the kernel and the userland to share certain
header files and to make the folder structure a bit more clear.

1 files changed, 93 insertions, 0 deletions

diff --git a/kernel/network/ethernet.c b/kernel/network/ethernet.c
new file mode 100644
index 0000000..e97ccbd
--- /dev/null
+++ b/kernel/network/ethernet.c
@@ -0,0 +1,93 @@
+#include <assert.h>
+#include <drivers/rtl8139.h>
+#include <kmalloc.h>
+#include <network/arp.h>
+#include <network/bytes.h>
+#include <network/ethernet.h>
+#include <network/ipv4.h>
+#include <stdio.h>
+
+struct ETHERNET_HEADER {
+  uint8_t mac_dst[6];
+  uint8_t mac_src[6];
+  uint16_t type;
+};
+
+uint32_t crc32(const char *buf, size_t len) {
+  static uint32_t table[256];
+  static int have_table = 0;
+  uint32_t rem;
+  uint8_t octet;
+  int i, j;
+  const char *p, *q;
+
+  if (have_table == 0) {
+    for (i = 0; i < 256; i++) {
+      rem = i;
+      for (j = 0; j < 8; j++) {
+        if (rem & 1) {
+          rem >>= 1;
+          rem ^= 0xedb88320;
+        } else
+          rem >>= 1;
+      }
+      table[i] = rem;
+    }
+    have_table = 1;
+  }
+
+  uint32_t crc = 0xFFFFFFFF;
+  q = buf + len;
+  for (p = buf; p < q; p++) {
+    octet = *p;
+    crc = (crc >> 8) ^ table[(crc & 0xff) ^ octet];
+  }
+  return ~crc;
+}
+
+void handle_ethernet(const uint8_t *packet, uint64_t packet_length) {
+  struct ETHERNET_HEADER *eth_header = (struct ETHERNET_HEADER *)packet;
+  packet += sizeof(struct ETHERNET_HEADER);
+  const uint8_t *payload = packet;
+  packet += packet_length - sizeof(struct ETHERNET_HEADER);
+  uint32_t crc = *((uint32_t *)packet - 1);
+  kprintf("PACKET crc: %x\n", crc);
+  kprintf("OUR OWN CALCULATED crc: %x\n",
+          crc32((const char *)eth_header, (packet_length - 4)));
+
+  uint16_t type = ntohs(eth_header->type);
+  switch (type) {
+  case 0x0806:
+    handle_arp(payload);
+    break;
+  case 0x0800:
+    handle_ipv4(payload, packet_length - sizeof(struct ETHERNET_HEADER) - 4);
+    break;
+  default:
+    kprintf("Can't handle ethernet type\n");
+    break;
+  }
+}
+
+void send_ethernet_packet(uint8_t mac_dst[6], uint16_t type, uint8_t *payload,
+                          uint64_t payload_length) {
+  // FIXME: Janky allocation, do this better
+  uint64_t buffer_size =
+      sizeof(struct ETHERNET_HEADER) + payload_length + sizeof(uint32_t);
+  uint8_t *buffer = kmalloc(buffer_size);
+  uint8_t *buffer_start = buffer;
+  struct ETHERNET_HEADER *eth_header = (struct ETHERNET_HEADER *)buffer;
+  buffer += sizeof(struct ETHERNET_HEADER);
+  memcpy(buffer, payload, payload_length);
+  buffer += payload_length;
+
+  memcpy(eth_header->mac_dst, mac_dst, sizeof(uint8_t[6]));
+  get_mac_address(eth_header->mac_src);
+  eth_header->type = htons(type);
+  *(uint32_t *)(buffer) =
+      htonl(crc32((const char *)buffer_start, buffer_size - 4));
+
+  assert(rtl8139_send_data(buffer_start, buffer_size));
+  kfree(buffer_start);
+  kprintf("sent data\n");
+}