Kernel/LibC/Networking: Be able to send UDP messages

Now it can send UDP messages to a specific IP address and libc has
enough to create a basic UDP ECHO server, that is kinda cool.

2 files changed, 34 insertions, 0 deletions

diff --git a/scalls/sendto.c b/scalls/sendto.c
new file mode 100644
index 0000000..48c4020
--- /dev/null
+++ b/scalls/sendto.c
@@ -0,0 +1,23 @@
+#include <assert.h>
+#include <network/bytes.h>
+#include <network/udp.h>
+#include <scalls/sendto.h>
+
+size_t syscall_sendto(int socket, const void *message, size_t length,
+           int flags, struct t_two_args *extra_args /*
+	   const struct sockaddr *dest_addr,
+           socklen_t dest_len*/) {
+  const struct sockaddr *dest_addr = (const struct sockaddr *)extra_args->a;
+  socklen_t dest_len = (socklen_t)extra_args->b;
+  (void)dest_len;
+  vfs_fd_t *fd = get_vfs_fd(socket);
+  assert(fd);
+  SOCKET *s = (SOCKET *)fd->inode->internal_object;
+  OPEN_INET_SOCKET *inet = s->child;
+  assert(inet);
+  struct sockaddr_in in;
+  in.sin_addr.s_addr = inet->address;
+  in.sin_port = inet->port;
+  send_udp_packet(&in, (const struct sockaddr_in *)dest_addr, message, length);
+  return length; // FIXME: This is probably not true.
+}
diff --git a/scalls/sendto.h b/scalls/sendto.h
new file mode 100644
index 0000000..0f852de
--- /dev/null
+++ b/scalls/sendto.h
@@ -0,0 +1,11 @@
+#include <socket.h>
+#include <stdint.h>
+
+struct t_two_args {
+  uint32_t a;
+  uint32_t b;
+};
+size_t syscall_sendto(int socket, const void *message, size_t length,
+           int flags, struct t_two_args *extra_args /*
+	   const struct sockaddr *dest_addr,
+           socklen_t dest_len*/);