IPv4: Begin fleshing out TCP support.

Author: https://github.com/awesomekling
Commit: c588653f76

Kernel/IPv4Socket.cpp

@@ -93,7 +93,11 @@ KResult IPv4Socket::connect(const sockaddr* address, socklen_t address_size)
     if (address->sa_family != AF_INET)
         return KResult(-EINVAL);
 
-    ASSERT_NOT_REACHED();
+    auto& ia = *(const sockaddr_in*)address;
+    m_destination_address = IPv4Address((const byte*)&ia.sin_addr.s_addr);
+    m_destination_port = ntohs(ia.sin_port);
+
+    return KSuccess;
 }
 
 void IPv4Socket::attach_fd(SocketRole)
@@ -177,9 +181,11 @@ ssize_t IPv4Socket::sendto(const void* data, size_t data_length, int flags, cons
         return -EAFNOSUPPORT;
     }
 
-    auto& ia = *(const sockaddr_in*)addr;
+    if (addr) {
-    m_destination_address = IPv4Address((const byte*)&ia.sin_addr.s_addr);
+        auto& ia = *(const sockaddr_in*)addr;
-    m_destination_port = ntohs(ia.sin_port);
+        m_destination_address = IPv4Address((const byte*)&ia.sin_addr.s_addr);
+        m_destination_port = ntohs(ia.sin_port);
+    }
 
     allocate_source_port_if_needed();
 

Kernel/NetworkTask.cpp

@@ -3,6 +3,7 @@
 #include <Kernel/ARP.h>
 #include <Kernel/ICMP.h>
 #include <Kernel/UDP.h>
+#include <Kernel/TCP.h>
 #include <Kernel/IPv4.h>
 #include <Kernel/IPv4Socket.h>
 #include <Kernel/Process.h>
@@ -10,14 +11,16 @@
 #include <AK/Lock.h>
 
 //#define ETHERNET_DEBUG
-//#define IPV4_DEBUG
+#define IPV4_DEBUG
 //#define ICMP_DEBUG
 #define UDP_DEBUG
+#define TCP_DEBUG
 
 static void handle_arp(const EthernetFrameHeader&, int frame_size);
 static void handle_ipv4(const EthernetFrameHeader&, int frame_size);
 static void handle_icmp(const EthernetFrameHeader&, int frame_size);
 static void handle_udp(const EthernetFrameHeader&, int frame_size);
+static void handle_tcp(const EthernetFrameHeader&, int frame_size);
 
 Lockable<HashMap<IPv4Address, MACAddress>>& arp_table()
 {
@@ -152,6 +155,8 @@ void handle_ipv4(const EthernetFrameHeader& eth, int frame_size)
         return handle_icmp(eth, frame_size);
     case IPv4Protocol::UDP:
         return handle_udp(eth, frame_size);
+    case IPv4Protocol::TCP:
+        return handle_tcp(eth, frame_size);
     default:
         kprintf("handle_ipv4: Unhandled protocol %u\n", packet.protocol());
         break;
@@ -244,3 +249,44 @@ void handle_udp(const EthernetFrameHeader& eth, int frame_size)
     ASSERT(socket->source_port() == udp_packet.destination_port());
     socket->did_receive(ByteBuffer::copy((const byte*)&ipv4_packet, sizeof(IPv4Packet) + ipv4_packet.payload_size()));
 }
+
+void handle_tcp(const EthernetFrameHeader& eth, int frame_size)
+{
+    (void)frame_size;
+    auto& ipv4_packet = *static_cast<const IPv4Packet*>(eth.payload());
+
+    auto* adapter = NetworkAdapter::from_ipv4_address(ipv4_packet.destination());
+    if (!adapter) {
+        kprintf("handle_tcp: this packet is not for me, it's for %s\n", ipv4_packet.destination().to_string().characters());
+        return;
+    }
+
+    auto& tcp_packet = *static_cast<const TCPPacket*>(ipv4_packet.payload());
+#ifdef TCP_DEBUG
+    kprintf("handle_tcp: source=%s:%u, destination=%s:%u seq=%u, ack=%u, flags=%w, window_size=%u\n",
+        ipv4_packet.source().to_string().characters(),
+        tcp_packet.source_port(),
+        ipv4_packet.destination().to_string().characters(),
+        tcp_packet.destination_port(),
+        tcp_packet.sequence_number(),
+        tcp_packet.ack_number(),
+        tcp_packet.flags(),
+        tcp_packet.window_size()
+    );
+#endif
+
+    RetainPtr<IPv4Socket> socket;
+    {
+        LOCKER(IPv4Socket::sockets_by_tcp_port().lock());
+        auto it = IPv4Socket::sockets_by_tcp_port().resource().find(tcp_packet.destination_port());
+        if (it == IPv4Socket::sockets_by_tcp_port().resource().end())
+            return;
+        ASSERT((*it).value);
+        socket = *(*it).value;
+    }
+
+    LOCKER(socket->lock());
+    ASSERT(socket->type() == SOCK_STREAM);
+    ASSERT(socket->source_port() == tcp_packet.destination_port());
+    socket->did_receive(ByteBuffer::copy((const byte*)&ipv4_packet, sizeof(IPv4Packet) + ipv4_packet.payload_size()));
+}

Kernel/TCP.h

@@ -0,0 +1,49 @@
+#pragma once
+
+#include <Kernel/IPv4.h>
+
+class [[gnu::packed]] TCPPacket {
+public:
+    TCPPacket() { }
+    ~TCPPacket() { }
+
+    word source_port() const { return m_source_port; }
+    void set_source_port(word port) { m_source_port = port; }
+
+    word destination_port() const { return m_destination_port; }
+    void set_destination_port(word port) { m_destination_port = port; }
+
+    dword sequence_number() const { return m_sequence_number; }
+    void set_sequence_number(dword number) { m_sequence_number = number; }
+
+    dword ack_number() const { return m_ack_number; }
+    void set_ack_number(dword number) { m_ack_number = number; }
+
+    word flags() const { return m_flags; }
+    void set_flags(word flags) { m_flags = flags; }
+
+    word window_size() const { return m_window_size; }
+    void set_window_size(word window_size) { m_window_size = window_size; }
+
+    word checksum() const { return m_checksum; }
+    void set_checksum(word checksum) { m_checksum = checksum; }
+
+    word urgent() const { return m_urgent; }
+    void set_urgent(word urgent) { m_urgent = urgent; }
+
+    const void* payload() const { return this + 1; }
+    void* payload() { return this + 1; }
+
+private:
+    NetworkOrdered<word> m_source_port;
+    NetworkOrdered<word> m_destination_port;
+    NetworkOrdered<dword> m_sequence_number;
+    NetworkOrdered<dword> m_ack_number;
+
+    NetworkOrdered<word> m_flags;
+    NetworkOrdered<word> m_window_size;
+    NetworkOrdered<word> m_checksum;
+    NetworkOrdered<word> m_urgent;
+};
+
+static_assert(sizeof(UDPPacket) == 8);

Kernel/run

@@ -11,6 +11,11 @@ elif [ "$1" = "qtap" ]; then
     sudo qemu-system-i386 -s -m 32 -object filter-dump,id=hue,netdev=br0,file=e1000.pcap -netdev tap,ifname=tap0,id=br0 -device e1000,netdev=br0 -drive format=raw,file=.floppy-image,if=floppy -drive format=raw,file=_fs_contents 
 else
     # ./run: qemu with user networking
-    qemu-system-i386 -s -m 32 -object filter-dump,id=hue,netdev=breh,file=e1000.pcap -netdev user,id=breh -device e1000,netdev=breh -drive format=raw,file=.floppy-image,if=floppy -drive format=raw,file=_fs_contents 
+    qemu-system-i386 -s -m 32 \
+        -object filter-dump,id=hue,netdev=breh,file=e1000.pcap \
+        -netdev user,id=breh,hostfwd=tcp:127.0.0.1:8888-192.168.5.2:8888 \
+        -device e1000,netdev=breh \
+        -drive format=raw,file=.floppy-image,if=floppy \
+        -drive format=raw,file=_fs_contents
 fi