icpm echo

Author: no382001

kernel/kernel.c

@@ -36,27 +36,20 @@ void kernel_main(void) {
   arp_init();
   serial_debug("arp done...");
 
-  uint8_t mac_addr[6];
-  mac_addr[0] = 0xAA;
-  mac_addr[1] = 0xBB;
-  mac_addr[2] = 0xCC;
-  mac_addr[3] = 0xDD;
-  mac_addr[4] = 0xEE;
-  mac_addr[5] = 0xFF;
+  uint8_t mac_addr[] = {0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF};
   get_mac_addr(mac_addr);
 
-  uint8_t ip_addr[6];
-  ip_addr[0] = 10;
-  ip_addr[1] = 0;
-  ip_addr[2] = 2;
-  ip_addr[3] = 15;
+  uint8_t ip_addr[] = {10, 0, 2, 15};
   char *str = "this is a message sent from the OS";
 
   /*
   ethernet_send_packet(mac_addr, (void *)str, strlen(str), 0x0021);
   ip_send_packet(ip_addr, (void *)str, strlen(str));
   */
 
+  uint8_t host_ip[] = {10, 0, 2, 2};
+  icmp_send_echo_request(host_ip, 1234, 1, "Test ping to host", 16);
+
   // this does not work i cant seem to set up the network on wsl2 qemu
   // the packet looks okay, but i cant reach the dhcp server
   /*

net/icmp.c

@@ -0,0 +1,40 @@
+#include "icmp.h"
+#include "drivers/serial.h"
+#include "libc/heap.h"
+#include "libc/mem.h"
+#include "network.h"
+
+void icmp_send_packet(uint8_t *dst_ip, uint8_t type, uint8_t code, uint16_t id,
+                      uint16_t sequence, void *data, uint32_t data_len) {
+  serial_debug("sending icmp packet %d to %d.%d.%d.%d", type, dst_ip[0],
+               dst_ip[1], dst_ip[2], dst_ip[3]);
+
+  uint32_t icmp_size = sizeof(icmp_packet_t) + data_len;
+
+  icmp_packet_t *packet = (icmp_packet_t *)kmalloc(icmp_size);
+  if (!packet) {
+    serial_debug("failed to allocate memory for ICMP packet");
+    return;
+  }
+
+  packet->type = type;
+  packet->code = code;
+  packet->checksum = 0;
+  packet->id = htons(id);
+  packet->sequence = htons(sequence);
+
+  if (data && data_len > 0) {
+    memcpy(packet->data, data, data_len);
+  }
+
+  packet->checksum = _ip_calculate_checksum((ip_packet_t *)packet, icmp_size);
+
+  _ip_send_packet(dst_ip, packet, icmp_size, PROTOCOL_ICMP);
+
+  kfree(packet);
+}
+
+void icmp_send_echo_request(uint8_t *dst_ip, uint16_t id, uint16_t sequence,
+                            void *data, uint32_t data_len) {
+  icmp_send_packet(dst_ip, ICMP_ECHO_REQUEST, 0, id, sequence, data, data_len);
+}

net/icmp.h

@@ -0,0 +1,28 @@
+#pragma once
+#include "ip.h"
+
+#define ICMP_ECHO_REPLY 0
+#define ICMP_DEST_UNREACHABLE 3
+#define ICMP_SOURCE_QUENCH 4
+#define ICMP_REDIRECT 5
+#define ICMP_ECHO_REQUEST 8
+#define ICMP_TIME_EXCEEDED 11
+#define ICMP_PARAMETER_PROBLEM 12
+
+typedef struct icmp_packet {
+  uint8_t type;
+  uint8_t code;
+  uint16_t checksum;
+  uint16_t id;
+  uint16_t sequence;
+  uint8_t data[];
+} __attribute__((packed)) icmp_packet_t;
+
+void icmp_send_packet(uint8_t *dst_ip, uint8_t type, uint8_t code, uint16_t id,
+                      uint16_t sequence, void *data, uint32_t data_len);
+
+void icmp_handle_packet(icmp_packet_t *packet, uint16_t length,
+                        uint8_t *src_ip);
+
+void icmp_send_echo_request(uint8_t *dst_ip, uint16_t id, uint16_t sequence,
+                            void *data, uint32_t data_len);

net/ip.c

@@ -24,16 +24,18 @@ void get_ip_str(char *ip_str, uint8_t *ip) {
   }
 }
 
-uint16_t ip_calculate_checksum(ip_packet_t *packet) {
+uint16_t _ip_calculate_checksum(ip_packet_t *packet, int size) {
   // treat the packet header as a 2-byte-integer array
   // sum all integers up and flip all bits
-  int array_size = sizeof(ip_packet_t) / 2;
+  if (size == 0) {
+    size = sizeof(ip_packet_t) / 2;
+  }
   uint32_t sum = 0;
   uint16_t value;
 
   uint8_t *byte_ptr = (uint8_t *)packet;
 
-  for (int i = 0; i < array_size; i++) {
+  for (int i = 0; i < size; i++) {
     memcpy(&value, &byte_ptr[i * 2], sizeof(uint16_t));
     sum += flip_short(value);
   }
@@ -45,7 +47,16 @@ uint16_t ip_calculate_checksum(ip_packet_t *packet) {
   return ret;
 }
 
+uint16_t ip_calculate_checksum(ip_packet_t *packet) {
+  return _ip_calculate_checksum(packet, 0);
+}
+
 void ip_send_packet(uint8_t *dst_ip, void *data, uint32_t len) {
+  _ip_send_packet(dst_ip, data, len, PROTOCOL_UDP); // Assuming UDP for DHCP
+}
+
+void _ip_send_packet(uint8_t *dst_ip, void *data, uint32_t len,
+                     uint8_t protocol) {
   serial_debug("sending ip packet to %d.%d.%d.%d with data length %d",
                dst_ip[0], dst_ip[1], dst_ip[2], dst_ip[3], len);
 
@@ -69,16 +80,15 @@ void ip_send_packet(uint8_t *dst_ip, void *data, uint32_t len) {
 
   // TTL and protocol
   packet->ttl = 64;
-  packet->protocol = PROTOCOL_UDP; // Assuming UDP for DHCP
+  packet->protocol = protocol;
 
   uint8_t my_ip_address[4] = {0, 0, 0, 0};
 
   memcpy(packet->src_ip, my_ip_address, 4);
   memcpy(packet->dst_ip, dst_ip, 4);
 
   packet->header_checksum = 0;
-  packet->header_checksum =
-      ip_calculate_checksum(packet);
+  packet->header_checksum = ip_calculate_checksum(packet);
   serial_debug("ip checksum = %x", ntohs(packet->header_checksum));
 
   memcpy(packet->data, data, len);

net/ip.h

@@ -7,8 +7,9 @@
 #define IP_PACKET_NO_FRAGMENT 2
 #define IP_IS_LAST_FRAGMENT 4
 
-#define PROTOCOL_UDP 17
+#define PROTOCOL_ICMP 1
 #define PROTOCOL_TCP 6
+#define PROTOCOL_UDP 17
 
 typedef struct ip_packet {
   uint8_t version_ihl;      // version (4 bits) + IHL (4 bits)
@@ -26,5 +27,8 @@ typedef struct ip_packet {
 
 void get_ip_str(char *ip_str, uint8_t *ip);
 uint16_t ip_calculate_checksum(ip_packet_t *packet);
+uint16_t _ip_calculate_checksum(ip_packet_t *packet, int size);
 void ip_send_packet(uint8_t *dst_ip, void *data, uint32_t len);
+void _ip_send_packet(uint8_t *dst_ip, void *data, uint32_t len,
+                     uint8_t protocol);
 void ip_handle_packet(ip_packet_t *packet);

setup_network.sh

@@ -1,3 +1,3 @@
 ip tuntap add dev tap0 mode tap
 ip link set dev tap0 up
-ip addr add 192.168.100.1/24 dev tap0
+#ip addr add 192.168.100.1/24 dev tap0

start_9p_fs.sh

@@ -0,0 +1,6 @@
+# install u9fs, and c9
+
+sudo socat TCP-LISTEN:564,fork EXEC:"u9fs -a none -D -l u9fs.log -u nobody ./disk/root"
+
+# dial tcp!127.0.0.1!564 in c9 with fs9pc:191 nobody, or none
+# fstat "/"