Kernel/Networking/LibC: Add syscalls and libc functions for UDP

This allows a UDP server to be created in userland and read data.
Currently it can't send data and is very very simplistic.

Code is horrible and probably needs some fixing until it can be further built
upon.

1 files changed, 26 insertions, 0 deletions

diff --git a/network/udp.c b/network/udp.c
new file mode 100644
index 0000000..fb8ba44
--- /dev/null
+++ b/network/udp.c
@@ -0,0 +1,26 @@
+#include <assert.h>
+#include <network/bytes.h>
+#include <network/udp.h>
+#include <socket.h>
+
+void handle_udp(const uint8_t *payload, uint32_t packet_length) {
+  assert(packet_length >= 8);
+  uint16_t source_port = ntohs(*(uint16_t *)payload);
+  uint16_t dst_port = ntohs(*(uint16_t *)(payload + 2));
+  uint16_t length = ntohs(*(uint16_t *)(payload + 4));
+  assert(length == packet_length);
+  kprintf("source_port: %d\n", source_port);
+  kprintf("dst_port: %d\n", dst_port);
+  uint32_t data_length = length - 8;
+  const uint8_t *data = payload + 8;
+
+  // Find the open port
+  OPEN_INET_SOCKET *in_s = find_open_udp_port(htons(dst_port));
+  assert(in_s);
+  SOCKET *s = in_s->s;
+  vfs_fd_t *fifo_file = s->ptr_socket_fd;
+  raw_vfs_pwrite(fifo_file, (char *)data, data_length, 0);
+  for (uint32_t i = 0; i < data_length; i++) {
+    kprintf("%c", data[i]);
+  }
+}