From 4d60b8da9cdcd4716fe65c8872ec60a14d2c1e48 Mon Sep 17 00:00:00 2001
From: Oskar <oskar@odeb12.480>
Date: Sun, 2 Jun 2024 21:32:41 +0200
Subject: listen-DGRAM which is basically a version of listen but with UDP

---
 listen-DGRAM.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 listen-DGRAM.c

(limited to 'listen-DGRAM.c')

diff --git a/listen-DGRAM.c b/listen-DGRAM.c
new file mode 100644
index 0000000..6110aa5
--- /dev/null
+++ b/listen-DGRAM.c
@@ -0,0 +1,90 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <signal.h>
+ 
+#define __FAIL EXIT_FAILURE
+#define BACKLOG 2
+
+size_t bytes_recieved = 0;
+
+void INThandler() {
+
+   	fprintf(stderr, " SIGINT\n");
+	fprintf(stdout, "bytes recieved: %ld\n", bytes_recieved);
+	exit(0);
+}
+
+int main () {
+
+	int sockfd = -1; // socket fd
+	int gai_result; // result from getaddrinfo
+	int bind_result = -1; // result from bind
+	struct addrinfo *res; // Pointer to linked list sent back by gai
+	struct addrinfo *p; // for linked list stuff
+	struct addrinfo hints; // Options we pass to gai
+	memset(&hints, 0, sizeof(hints)); // We set this struct to 0 and then give it all the options we want below
+	hints.ai_family = AF_INET;
+	hints.ai_socktype = SOCK_DGRAM;
+	hints.ai_flags = AI_PASSIVE;
+
+	gai_result = getaddrinfo(NULL, "62000", &hints, &res); // NULL because we are going to listen
+	if (gai_result != 0) {
+   		fprintf(stderr, "gai_result: %d\n", gai_result);
+   		exit(__FAIL);
+	}
+	
+	for (p = res ; p != NULL ; p = p->ai_next) { // Loop 
+
+		sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol); // Socket, get the family, socktype and protocol.
+		if (sockfd == -1) {
+			fprintf(stderr, "sockfd: %d\n", sockfd);
+			continue;
+		}
+
+		bind_result = bind(sockfd, p->ai_addr, p->ai_addrlen); // Bind to socket fd. pass our own address (ai_addr) and the length
+		if (bind_result != 0) {
+			fprintf(stderr, "bind_result: %d\n", bind_result);
+			close(sockfd);
+			continue;
+		}
+	}
+	if (sockfd == -1 || bind_result == -1) {
+		exit(__FAIL);
+	}
+	
+	freeaddrinfo(res); // free the info because we dont need it anymore
+
+	fprintf(stdout, "Listening...\n");
+	
+	struct sockaddr_storage from;
+	socklen_t fromlen = sizeof(struct sockaddr_storage);
+	size_t rlen = 1024;
+	int recv_ret;
+	
+	signal(SIGINT, INThandler);
+	while(true) {
+
+		char recvmsg[rlen]; 
+		recv_ret = recvfrom(sockfd, recvmsg, rlen, 0, (struct sockaddr *)&from, &fromlen);
+		bytes_recieved = bytes_recieved+recv_ret;
+		if (recv_ret < 1) {
+			break;
+		}
+		recvmsg[recv_ret] = '\0';
+		fprintf(stdout, "%s", recvmsg);
+		//fprintf(stdout, "loop");
+		memset(&recvmsg, 0, rlen);
+	}
+	 
+	return 0;
+}
-- 
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