Kernel: Record network statistics and expose as JSON

This is comprised of five small changes:

* Keep a counter for tx/rx packets/bytes per TCP socket
* Keep a counter for tx/rx packets/bytes per network adapter
* Expose that data in /proc/net_tcp and /proc/netadapters
* Convert /proc/netadapters to JSON
* Fix up ifconfig to read the JSON from netadapters

Kernel/Net/NetworkAdapter.cpp

@@ -52,6 +52,8 @@ void NetworkAdapter::send(const MACAddress& destination, const ARPPacket& packet
     eth->set_source(mac_address());
     eth->set_destination(destination);
     eth->set_ether_type(EtherType::ARP);
+    m_packets_out++;
+    m_bytes_out += size_in_bytes;
     memcpy(eth->payload(), &packet, sizeof(ARPPacket));
     send_raw((u8*)eth, size_in_bytes);
 }
@@ -74,6 +76,8 @@ void NetworkAdapter::send_ipv4(const MACAddress& destination_mac, const IPv4Addr
     ipv4.set_ident(1);
     ipv4.set_ttl(64);
     ipv4.set_checksum(ipv4.compute_checksum());
+    m_packets_out++;
+    m_bytes_out += size_in_bytes;
     memcpy(ipv4.payload(), payload, payload_size);
     send_raw((const u8*)&eth, size_in_bytes);
 }
@@ -81,6 +85,8 @@ void NetworkAdapter::send_ipv4(const MACAddress& destination_mac, const IPv4Addr
 void NetworkAdapter::did_receive(const u8* data, int length)
 {
     InterruptDisabler disabler;
+    m_packets_in++;
+    m_bytes_in += length;
     m_packet_queue.append(KBuffer::copy(data, length));
 }
 

Kernel/Net/NetworkAdapter.h

@@ -33,6 +33,11 @@ public:
 
     bool has_queued_packets() const { return !m_packet_queue.is_empty(); }
 
+    u32 packets_in() const { return m_packets_in; }
+    u32 bytes_in() const { return m_bytes_in; }
+    u32 packets_out() const { return m_packets_out; }
+    u32 bytes_out() const { return m_bytes_out; }
+
 protected:
     NetworkAdapter();
     void set_interface_name(const StringView& basename);
@@ -45,4 +50,8 @@ private:
     IPv4Address m_ipv4_address;
     SinglyLinkedList<KBuffer> m_packet_queue;
     String m_name;
+    u32 m_packets_in { 0 };
+    u32 m_bytes_in { 0 };
+    u32 m_packets_out { 0 };
+    u32 m_bytes_out { 0 };
 };

Kernel/Net/NetworkTask.cpp

@@ -334,6 +334,8 @@ void handle_tcp(const EthernetFrameHeader& eth, int frame_size)
         return;
     }
 
+    socket->record_incoming_data(ipv4_packet.payload_size());
+
 #ifdef TCP_DEBUG
     kprintf("handle_tcp: state=%s\n", TCPSocket::to_string(socket->state()));
 #endif

Kernel/Net/TCPSocket.cpp

@@ -117,6 +117,15 @@ void TCPSocket::send_tcp_packet(u16 flags, const void* payload, int payload_size
         tcp_packet.ack_number());
 #endif
     m_adapter->send_ipv4(MACAddress(), peer_address(), IPv4Protocol::TCP, buffer.data(), buffer.size());
+
+    m_packets_out++;
+    m_bytes_out += buffer.size();
+}
+
+void TCPSocket::record_incoming_data(int size)
+{
+    m_packets_in++;
+    m_bytes_in += size;
 }
 
 NetworkOrdered<u16> TCPSocket::compute_tcp_checksum(const IPv4Address& source, const IPv4Address& destination, const TCPPacket& packet, u16 payload_size)

Kernel/Net/TCPSocket.h

@@ -60,8 +60,13 @@ public:
     void set_sequence_number(u32 n) { m_sequence_number = n; }
     u32 ack_number() const { return m_ack_number; }
     u32 sequence_number() const { return m_sequence_number; }
+    u32 packets_in() const { return m_packets_in; }
+    u32 bytes_in() const { return m_bytes_in; }
+    u32 packets_out() const { return m_packets_out; }
+    u32 bytes_out() const { return m_bytes_out; }
 
     void send_tcp_packet(u16 flags, const void* = nullptr, int = 0);
+    void record_incoming_data(int);
 
     static Lockable<HashMap<IPv4SocketTuple, TCPSocket*>>& sockets_by_tuple();
     static TCPSocketHandle from_tuple(const IPv4SocketTuple& tuple);
@@ -85,6 +90,10 @@ private:
     u32 m_sequence_number { 0 };
     u32 m_ack_number { 0 };
     State m_state { State::Closed };
+    u32 m_packets_in { 0 };
+    u32 m_bytes_in { 0 };
+    u32 m_packets_out { 0 };
+    u32 m_bytes_out { 0 };
 };
 
 class TCPSocketHandle : public SocketHandle {