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.

1 files changed, 17 insertions, 0 deletions

diff --git a/userland/libc/sys/socket/recvfrom.c b/userland/libc/sys/socket/recvfrom.c
new file mode 100644
index 0000000..5bbfeea
--- /dev/null
+++ b/userland/libc/sys/socket/recvfrom.c
@@ -0,0 +1,17 @@
+#include <assert.h>
+#include <sys/socket.h>
+#include <syscall.h>
+
+struct two_args {
+  uint32_t a;
+  uint32_t b;
+};
+
+size_t recvfrom(int socket, void *buffer, size_t length, int flags,
+                struct sockaddr *address, socklen_t *address_len) {
+  struct two_args extra_args;
+  extra_args.a = address;
+  extra_args.b = address_len;
+
+  return syscall(SYS_RECVFROM, socket, buffer, length, flags, &extra_args);
+}