Userspace: Implement basic udp test program

userspace/CMakeLists.txt

@@ -35,6 +35,7 @@ set(USERSPACE_PROJECTS
 	test-mouse
 	test-sort
 	test-tcp
+	test-udp
 	test-unix-socket
 	touch
 	u8sum

userspace/test-udp/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.26)
+
+project(test-udp CXX)
+
+set(SOURCES
+	main.cpp
+)
+
+add_executable(test-udp ${SOURCES})
+target_compile_options(test-udp PUBLIC -O2 -g)
+target_link_libraries(test-udp PUBLIC libc)
+
+add_custom_target(test-udp-install
+	COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_BINARY_DIR}/test-udp ${BANAN_BIN}/
+	DEPENDS test-udp
+)

userspace/test-udp/main.cpp

@@ -0,0 +1,88 @@
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+int usage(const char* argv0)
+{
+	fprintf(stderr, "usage: %s [-s|-c] [-a addr] [-p port]\n", argv0);
+	return 1;
+}
+
+int main(int argc, char** argv)
+{
+	bool server = false;
+	uint32_t addr = 0;
+	uint16_t port = 0;
+
+	for (int i = 1; i < argc; i++)
+	{
+		if (strcmp(argv[i], "-s") == 0)
+			server = true;
+		else if (strcmp(argv[i], "-c") == 0)
+			server = false;
+		else if (strcmp(argv[i], "-a") == 0)
+			addr = inet_addr(argv[++i]);
+		else if (strcmp(argv[i], "-p") == 0)
+			sscanf(argv[++i], "%hu", &port);
+		else
+			return usage(argv[0]);
+	}
+
+	int socket = ::socket(AF_INET, SOCK_DGRAM, 0);
+	if (socket == -1)
+	{
+		perror("socket");
+		return 1;
+	}
+
+	if (server)
+	{
+		sockaddr_in bind_addr;
+		bind_addr.sin_family = AF_INET;
+		bind_addr.sin_port = htons(port);
+		bind_addr.sin_addr.s_addr = addr;
+
+		if (bind(socket, (sockaddr*)&bind_addr, sizeof(bind_addr)) == -1)
+		{
+			perror("bind");
+			return 1;
+		}
+
+		printf("listening on %s:%hu\n", inet_ntoa(bind_addr.sin_addr), ntohs(bind_addr.sin_port));
+
+		char buffer[1024];
+		sockaddr_in sender;
+		socklen_t sender_len = sizeof(sender);
+
+		if (recvfrom(socket, buffer, sizeof(buffer), 0, (sockaddr*)&sender, &sender_len) == -1)
+		{
+			perror("recvfrom");
+			return 1;
+		}
+
+		printf("received from %s:%hu\n", inet_ntoa(sender.sin_addr), ntohs(sender.sin_port));
+		printf("  %s\n", buffer);
+	}
+	else
+	{
+		const char buffer[] = "Hello from banan-os!";
+
+		sockaddr_in server_addr;
+		server_addr.sin_family = AF_INET;
+		server_addr.sin_port = htons(port);
+		server_addr.sin_addr.s_addr = addr;
+
+		printf("sending to %s:%hu\n", inet_ntoa(server_addr.sin_addr), ntohs(server_addr.sin_port));
+		if (sendto(socket, buffer, sizeof(buffer), 0, (sockaddr*)&server_addr, sizeof(server_addr)) == -1)
+		{
+			perror("sendto");
+			return 1;
+		}
+	}
+
+	close(socket);
+	return 0;
+}