Kernel: Fixup rtl8139, add basic ARP and ethernet support

Currently the ARP appears to be able to respond to requests.

6 files changed, 207 insertions, 0 deletions

diff --git a/network/arp.c b/network/arp.c
new file mode 100644
index 0000000..eb8aca3
--- /dev/null
+++ b/network/arp.c
@@ -0,0 +1,83 @@
+#include <assert.h>
+#include <drivers/rtl8139.h>
+#include <network/arp.h>
+#include <network/bytes.h>
+#include <network/ethernet.h>
+#include <stdio.h>
+#include <string.h>
+
+struct ARP_DATA {
+  uint16_t htype;   // Hardware type
+  uint16_t ptype;   // Protocol type
+  uint8_t hlen;     // Hardware address length (Ethernet = 6)
+  uint8_t plen;     // Protocol address length (IPv4 = 4)
+  uint16_t opcode;  // ARP Operation Code
+  uint8_t srchw[6]; // Source hardware address - hlen bytes (see above)
+  uint8_t srcpr[4]; // Source protocol address - plen bytes (see above).
+                    // If IPv4 can just be a "u32" type.
+  uint8_t dsthw[6]; // Destination hardware address - hlen bytes (see above)
+  uint8_t dstpr[4]; // Destination protocol address - plen bytes (see
+                    // above). If IPv4 can just be a "u32" type.
+};
+
+// FIXME: This is hardcoded, don't do this.
+uint8_t ip_address[4] = {10, 0, 2, 15};
+
+void print_mac(const char *str, uint8_t *mac) {
+  kprintf("%s: ", str);
+  for (int i = 0; i < 6; i++) {
+    kprintf("%x", mac[i]);
+    if (5 != i)
+      kprintf(":");
+  }
+  kprintf("\n");
+}
+
+void print_ip(const char *str, uint8_t *ip) {
+  kprintf("%s: ", str);
+  for (int i = 0; i < 4; i++) {
+    kprintf("%d", ip[i]);
+    if (3 != i)
+      kprintf(".");
+  }
+  kprintf("\n");
+}
+
+void handle_arp(uint8_t *payload) {
+  struct ARP_DATA *data = (struct ARP_DATA *)payload;
+
+  // Assert that communication is over ethernet
+  assert(1 == ntohs(data->htype));
+  // Assert it is a request
+  assert(0x0001 == ntohs(data->opcode));
+  // Assert that request uses IP
+  assert(0x0800 == ntohs(data->ptype));
+
+  assert(6 == data->hlen);
+  assert(4 == data->plen);
+  print_mac("srchw: ", data->srchw);
+  print_ip("srcpr: ", data->srcpr);
+
+  print_mac("dsthw: ", data->dsthw);
+  print_ip("dstpr: ", data->dstpr);
+
+  uint8_t mac[6];
+  get_mac_address(mac);
+  print_mac("THIS DEVICE MAC: ", mac);
+  assert(0 == memcmp(data->dstpr, ip_address, sizeof(uint8_t[4])));
+
+  // Now we have to construct a ARP response
+  struct ARP_DATA response;
+  response.htype = htons(1);
+  response.ptype = htons(0x0800);
+  response.opcode = htons(0x00002);
+  response.hlen = 6;
+  response.plen = 4;
+  get_mac_address(response.srchw);
+  memcpy(response.srcpr, ip_address, sizeof(uint8_t[4]));
+
+  memcpy(response.dsthw, data->srchw, sizeof(uint8_t[6]));
+  memcpy(response.dstpr, data->srcpr, sizeof(uint8_t[4]));
+
+  send_ethernet_packet(data->srchw, 0x0806, (uint8_t*)&response, sizeof(response));
+}
diff --git a/network/arp.h b/network/arp.h
new file mode 100644
index 0000000..1e8df1b
--- /dev/null
+++ b/network/arp.h
@@ -0,0 +1,3 @@
+#include <stdint.h>
+
+void handle_arp(uint8_t *payload);
diff --git a/network/bytes.c b/network/bytes.c
new file mode 100644
index 0000000..94afa73
--- /dev/null
+++ b/network/bytes.c
@@ -0,0 +1,10 @@
+#include <network/bytes.h>
+
+uint16_t ntohs(uint16_t net) { return (net >> 8) | (net << 8); }
+
+uint16_t htons(uint16_t net) { return (net >> 8) | (net << 8); }
+
+uint32_t htonl(uint32_t net) {
+  return (((net & 0x000000FF) << 24) | ((net & 0x0000FF00) << 8) |
+          ((net & 0x00FF0000) >> 8) | ((net & 0xFF000000) >> 24));
+}
diff --git a/network/bytes.h b/network/bytes.h
new file mode 100644
index 0000000..c291589
--- /dev/null
+++ b/network/bytes.h
@@ -0,0 +1,5 @@
+#include <stdint.h>
+
+uint16_t ntohs(uint16_t net);
+uint16_t htons(uint16_t net);
+uint32_t htonl(uint32_t net);
diff --git a/network/ethernet.c b/network/ethernet.c
new file mode 100644
index 0000000..ae8e814
--- /dev/null
+++ b/network/ethernet.c
@@ -0,0 +1,101 @@
+#include <assert.h>
+#include <drivers/rtl8139.h>
+#include <kmalloc.h>
+#include <network/arp.h>
+#include <network/bytes.h>
+#include <network/ethernet.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(uint8_t *packet, uint64_t packet_length) {
+  struct ETHERNET_HEADER *eth_header = (struct ETHERNET_HEADER *)packet;
+  packet += sizeof(struct ETHERNET_HEADER);
+  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)));
+
+  kprintf("mac dst: ");
+  for (int i = 0; i < 6; i++)
+    kprintf("%x", eth_header->mac_dst[i]);
+  kprintf("\n");
+  kprintf("mac src: ");
+  for (int i = 0; i < 6; i++)
+    kprintf("%x", eth_header->mac_src[i]);
+  kprintf("\n");
+
+  uint16_t type = ntohs(eth_header->type);
+  kprintf("Etheretype: %x\n", type);
+  switch (type) {
+  case 0x0806:
+    handle_arp(payload);
+    break;
+  case 0x0800:
+    kprintf("IPV4 message\n");
+    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));
+  kprintf("sent data\n");
+}
diff --git a/network/ethernet.h b/network/ethernet.h
new file mode 100644
index 0000000..88a4dc6
--- /dev/null
+++ b/network/ethernet.h
@@ -0,0 +1,5 @@
+#include <stdint.h>
+
+void handle_ethernet(uint8_t *packet, uint64_t packet_length);
+void send_ethernet_packet(uint8_t mac_dst[6], uint16_t type, uint8_t *payload,
+                          uint64_t payload_length);