some udp test code

.gitignore

@@ -1 +1,4 @@
 bin/
+out/
+net
+test

Makefile

@@ -0,0 +1,15 @@
+
+
+all: bin/net bin/test
+
+
+bin/net: net.c
+	mkdir -pv bin
+	gcc -o bin/net net.c
+
+bin/test: test.c
+	mkdir -pv bin
+	gcc -o bin/test test.c
+
+clean:
+	rm -rf bin

net.c

@@ -0,0 +1,93 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+#define PORT "4711"
+
+void *get_in_addr(struct sockaddr *sa)
+{
+    if (sa->sa_family == AF_INET) {
+        return &(((struct sockaddr_in*)sa)->sin_addr);
+    }
+
+    return &(((struct sockaddr_in6*)sa)->sin6_addr);
+}
+
+int main (int argc, char **argv) {
+
+	struct addrinfo hints, *servinfo;
+
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = AF_INET;      // IPv4
+	hints.ai_socktype = SOCK_DGRAM; // UDP
+	hints.ai_flags = AI_PASSIVE;
+
+	int rv;
+	if ((rv = getaddrinfo(NULL, PORT, &hints, &servinfo)) != 0) {
+		fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
+		return 1;
+	}
+
+	printf("got local address\n");
+	
+	struct addrinfo *info;
+	int sockfd;
+	char s[INET6_ADDRSTRLEN];
+	for (info = servinfo; info != NULL; info = info->ai_next) {
+/*		if (info->ai_addr) {
+			struct sockaddr_in* p = (struct sockaddr_in *)info->ai_addr;
+			inet_ntop(p->sin_family, &p->sin_addr, s, INET6_ADDRSTRLEN); 
+			printf("  %d: %s\n", info->ai_addr->sa_family, s);
+		}
+*/
+
+		if ((sockfd = socket(info->ai_family, info->ai_socktype, info->ai_protocol)) == -1) {
+			perror("sock");
+			continue; 
+		}
+
+		if (bind(sockfd, info->ai_addr, info->ai_addrlen) == -1) {
+			perror("bind");
+			continue; 
+		}
+
+		break;
+	}
+	if (!info) {
+		fprintf(stderr, "unbound\n");
+		return 2;
+	}
+	printf("check!\n");
+
+	freeaddrinfo(servinfo); // free whole list
+ 
+	struct sockaddr_storage their_addr;
+	socklen_t addr_len = sizeof their_addr;
+	int numbytes;
+	char buf[10000];
+	do {
+		if ((numbytes = recvfrom(sockfd, buf, 9999 , 0, (struct sockaddr *)&their_addr, &addr_len)) == -1) {
+	    	perror("recvfrom");
+		    exit(1);
+		}
+		
+		printf("listener: got packet from %s\n", inet_ntop(their_addr.ss_family, get_in_addr((struct sockaddr *)&their_addr), s, sizeof s));
+		printf("listener: packet is %d bytes long\n", numbytes);
+		buf[numbytes] = '\0';
+		printf("listener: packet contains \"%s\"\n", buf);
+	} while (strncmp(buf, "exit", 10000));
+
+
+	close(sockfd);
+	
+	return 0;
+}
+

test.c

@@ -0,0 +1,67 @@
+/*
+** talker.c -- a datagram "client" demo
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+#define SERVERPORT "4711"    // the port users will be connecting to
+
+int main(int argc, char *argv[])
+{
+    int sockfd;
+    struct addrinfo hints, *servinfo, *p;
+    int rv;
+    int numbytes;
+
+    if (argc != 3) {
+        fprintf(stderr,"usage: talker hostname message\n");
+        exit(1);
+    }
+
+    memset(&hints, 0, sizeof hints);
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_socktype = SOCK_DGRAM;
+
+    if ((rv = getaddrinfo(argv[1], SERVERPORT, &hints, &servinfo)) != 0) {
+        fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
+        return 1;
+    }
+
+    // loop through all the results and make a socket
+    for(p = servinfo; p != NULL; p = p->ai_next) {
+        if ((sockfd = socket(p->ai_family, p->ai_socktype,
+                p->ai_protocol)) == -1) {
+            perror("talker: socket");
+            continue;
+        }
+
+        break;
+    }
+
+    if (p == NULL) {
+        fprintf(stderr, "talker: failed to bind socket\n");
+        return 2;
+    }
+
+    if ((numbytes = sendto(sockfd, argv[2], strlen(argv[2]), 0,
+             p->ai_addr, p->ai_addrlen)) == -1) {
+        perror("talker: sendto");
+        exit(1);
+    }
+
+    freeaddrinfo(servinfo);
+
+    printf("talker: sent %d bytes to %s\n", numbytes, argv[1]);
+    close(sockfd);
+
+    return 0;
+}