Very simple icmp ping handling

6 files changed, 67 insertions, 35 deletions

diff --git a/.gitignore b/.gitignore
index 3ff5e8e..b2e2972 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,8 @@ compile_commands.json
 *.o
 *.elf
 *.bin
+*.log
+*.pcap
 
 .clangd/
 build/
diff --git a/kernel/Makefile b/kernel/Makefile
index e415454..1fc024f 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -23,7 +23,7 @@ LD = ../cross/opt/bin/i686-elf-ld
 OC = ../cross/opt/bin/i686-elf-objcopy
 AS = nasm
 
-CFLAGS = -Wall -Wextra -nostdlib -nostdinc -ffreestanding -fno-builtin -mno-red-zone -mgeneral-regs-only -std=c99 -m32 -pedantic-errors -Wl,-ekernel_main -I../libc/inc/ -Iinc/ -Dkernel -O0
+CFLAGS = -Wall -Wextra -Wno-address-of-packed-member -nostdlib -nostdinc -ffreestanding -fno-builtin -mno-red-zone -mgeneral-regs-only -std=c99 -m32 -pedantic-errors -Wl,-ekernel_main -I../libc/inc/ -Iinc/ -Dkernel -Ofast
 
 ASFLAGS = -f elf32
 
diff --git a/kernel/drivers/rtl8139.c b/kernel/drivers/rtl8139.c
index 6487eca..2fc8f07 100644
--- a/kernel/drivers/rtl8139.c
+++ b/kernel/drivers/rtl8139.c
@@ -25,6 +25,7 @@ u8 *rtl8139_get_mac()
 
 void rtl8139_receive_packet()
 {
+	printf("%x\n", current_packet_ptr);
 	u16 *t = (u16 *)(rx_buffer + current_packet_ptr);
 	u16 length = *(t + 1);
 	t += 2;
@@ -35,7 +36,7 @@ void rtl8139_receive_packet()
 
 	current_packet_ptr = (current_packet_ptr + length + 4 + 3) & (~3);
 
-	if (current_packet_ptr > RX_BUF_SIZE)
+	if (current_packet_ptr >= RX_BUF_SIZE)
 		current_packet_ptr -= RX_BUF_SIZE;
 
 	outw(rtl_iobase + RTL_PORT_RXPTR, current_packet_ptr - 0x10);
@@ -46,6 +47,7 @@ static u8 tsd_array[4] = { 0x10, 0x14, 0x18, 0x1C };
 static u8 tx_current = 0;
 void rtl8139_send_packet(void *data, u32 len)
 {
+	printf("Sending packet %d\n", len);
 	outl(rtl_iobase + tsad_array[tx_current], (u32)data);
 	outl(rtl_iobase + tsd_array[tx_current++], len);
 	if (tx_current > 3)
diff --git a/kernel/features/net.c b/kernel/features/net.c
index 7806504..1ebccb5 100644
--- a/kernel/features/net.c
+++ b/kernel/features/net.c
@@ -7,55 +7,74 @@
 #include <print.h>
 #include <rtl8139.h>
 
-int ethernet_send_packet(u8 *dst_mac_addr, u8 *data, int len, int prot)
+/**
+ * Checksums
+ */
+
+u16 ip_calculate_checksum(struct ip_packet *packet)
+{
+	u32 sum = 0;
+	u16 *s = (u16 *)packet;
+
+	for (int i = 0; i < 10; ++i)
+		sum += ntohs(s[i]);
+
+	if (sum > 0xFFFF)
+		sum = (sum >> 16) + (sum & 0xFFFF);
+
+	return sum;
+}
+
+/**
+ * Requests
+ */
+
+int ethernet_send_packet(u8 *dst, u8 *data, int len, int prot)
 {
 	struct ethernet_packet *packet = malloc(sizeof(*packet) + len);
-	void *packet_data = (u32 *)packet + sizeof(*packet);
-	memcpy(packet->src_mac_addr, rtl8139_get_mac(), 6);
-	memcpy(packet->dst_mac_addr, dst_mac_addr, 6);
-	memcpy(packet_data, data, len);
+	memcpy(packet->src, rtl8139_get_mac(), 6);
+	memcpy(packet->dst, dst, 6);
+	memcpy(packet->data, data, len);
 	packet->type = htons(prot);
 	rtl8139_send_packet(packet, sizeof(*packet) + len);
 	free(packet);
 	return len;
 }
 
-u16 ip_calculate_checksum(struct ip_packet *packet)
-{
-	int array_size = sizeof(*packet) / 2;
-	u16 *array = (u16 *)packet;
-	u32 sum = 0;
-	for (int i = 0; i < array_size; i++) {
-		u32 first_byte = *((u8 *)(&array[i]));
-		u32 second_byte = *((u8 *)(&array[i]) + 1);
-		sum += (first_byte << 8) | (second_byte);
-	}
-	u32 carry = sum >> 16;
-	sum = sum & 0x0000ffff;
-	sum = sum + carry;
-	u16 ret = ~sum;
-	return ret;
-}
-
 void ip_send_packet(u32 dst, void *data, int len, int prot)
 {
 	struct ip_packet *packet = malloc(sizeof(*packet) + len);
 	memset(packet, 0, sizeof(*packet));
-	packet->version = 4;
-	packet->ihl = 5; // 5 * 4 = 20B
+	packet->version_ihl = ((0x4 << 4) | (0x5 << 0));
 	packet->length = sizeof(*packet) + len;
 	packet->id = 0; // TODO: IP fragmentation
 	packet->ttl = 64;
 	packet->protocol = prot;
-	packet->src = 0;
+	packet->src = htonl(0x0a00022a);
 	packet->dst = dst;
-	void *packet_data = (u32 *)packet + packet->ihl * 4;
-	memcpy(packet_data, data, len);
+	/* void *packet_data = (u32 *)packet + 0x5 * 4; */
+	memcpy(packet->data, data, len);
 	packet->length = htons(sizeof(*packet) + len);
 	packet->checksum = htons(ip_calculate_checksum(packet));
 	// TODO: arp destination lookup
 	ethernet_send_packet((u8 *)0x424242424242, (u8 *)packet, htons(packet->length),
 			     ETHERNET_TYPE_IP4);
+	free(packet);
+}
+
+/**
+ * Responses
+ */
+
+void icmp_handle_packet(u32 dst, int len)
+{
+	struct icmp_packet *packet = malloc(sizeof(*packet) + len);
+	memset(packet, 0, sizeof(*packet));
+	packet->type = 0; // Ping reponse
+	packet->version = 0;
+	packet->checksum = 0;
+	ip_send_packet(dst, packet, sizeof(*packet) + len, IP_PROT_ICMP);
+	free(packet);
 }
 
 void ip_handle_packet(struct ip_packet *packet, int len)
@@ -63,7 +82,7 @@ void ip_handle_packet(struct ip_packet *packet, int len)
 	switch (packet->protocol) {
 	case IP_PROT_ICMP:
 		print("ICMP Packet!\n");
-		ip_send_packet(packet->src, packet->data, len, IP_PROT_ICMP);
+		icmp_handle_packet(packet->src, len);
 		break;
 	case IP_PROT_TCP:
 		print("TCP Packet!\n");
@@ -93,6 +112,10 @@ void ethernet_handle_packet(struct ethernet_packet *packet, int len)
 	}
 }
 
+/**
+ * Install
+ */
+
 void net_install()
 {
 	rtl8139_install();
diff --git a/kernel/inc/net.h b/kernel/inc/net.h
index 300c0bd..943583a 100644
--- a/kernel/inc/net.h
+++ b/kernel/inc/net.h
@@ -21,15 +21,14 @@
 #define IP_PROT_UDP 0x11
 
 struct ethernet_packet {
-	u8 dst_mac_addr[6];
-	u8 src_mac_addr[6];
+	u8 dst[6];
+	u8 src[6];
 	u16 type;
 	u8 data[];
 } __attribute__((packed));
 
 struct ip_packet {
-	u8 version : 4;
-	u8 ihl : 4;
+	u8 version_ihl;
 	u8 dscp_ecn;
 	u16 length;
 	u16 id;
@@ -42,6 +41,12 @@ struct ip_packet {
 	u8 data[];
 } __attribute__((packed));
 
+struct icmp_packet {
+	u8 type;
+	u8 version;
+	u16 checksum;
+} __attribute__((packed));
+
 void ethernet_handle_packet(struct ethernet_packet *packet, int len);
 void net_install();
 
diff --git a/run b/run
index 284a07e..7ce006b 100755
--- a/run
+++ b/run
@@ -12,7 +12,7 @@ no_ask="${2}"
 qemu_with_flags() {
     if [ -z "$network" ]; then network="rtl8139"; fi
     if [ "$network" != "false" ] && [ "$mode" = "net" ]; then
-        qemu-system-i386 -cpu max -no-reboot -vga std -rtc base=localtime -m 256M -smp 4 -netdev tap,helper=/usr/lib/qemu/qemu-bridge-helper,id=melvix_net -device $network,netdev=melvix_net,id=melvix_nic "$@"
+        qemu-system-i386 -cpu max -no-reboot -vga std -rtc base=localtime -m 256M -smp 4 -netdev tap,helper=/usr/lib/qemu/qemu-bridge-helper,id=melvix_net -device $network,netdev=melvix_net,id=melvix_nic -object filter-dump,id=melvix_nic,netdev=melvix_net,file=dump.pcap "$@"
     else
         qemu-system-i386 -cpu max -no-reboot -vga std -rtc base=localtime -m 256M -smp 4 "$@"
     fi