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POWhats wrong with my UDP Client Server?
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1829660
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2009-12-01T23:23:07.707
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I have a UDP Server that should sit and wait for a client to connect to it, and send it a string of a filename. Right now I just want it to echo back the filename to the client. Here is my code Server <pre><code>#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 MAXBUFLEN 1024 // Usage: ./server PORT int main(int argc, char *argv[]) { int sockfd; struct sockaddr_in server; size_t clientSize; struct sockaddr_storage client; char buf[MAXBUFLEN]; int portno = atoi(argv[1]); int numbytes; printf("Port: %d\n", portno); // Create UDP Socket if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) { perror("Can't create socket"); exit(-1); } // Configure socket memset(&server, 0, sizeof server); server.sin_family = AF_INET; // Use IPv4 server.sin_addr.s_addr = INADDR_ANY; // My IP server.sin_port = htons(portno); // Server Port // Bind socket if ((bind(sockfd, (struct sockaddr *) &server, sizeof(server))) == -1) { close(sockfd); perror("Can't bind"); } while (1) { printf("Waiting for data...\n"); // Receive data from Client clientSize = sizeof(client); numbytes = recvfrom(sockfd, buf, MAXBUFLEN-1,0, (struct sockaddr *) &client, &clientSize); buf[numbytes] = '\0'; printf("client sent: %s\n", buf); // Rely to client sendto(sockfd, buf, MAXBUFLEN-1, 0, (struct sockaddr *) &client, &clientSize); } printf("Closing"); close(sockfd); return 0; } </code></pre> Client <pre><code>#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 MAXBUFLEN 1024 //Usage: ./client PORT IP FILE int main(int argc, char *argv[]) { int sockfd; struct sockaddr_in server; // struct sockaddr_storage client; char buf[MAXBUFLEN]; int portno = atoi(argv[1]); char *serverIP = argv[2]; char *filename = argv[3]; int numbytes; printf("Port: %d, IP:%s, File:%s\n", portno, serverIP, filename); // Create UDP Socket if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) { perror("Can't create socket"); exit(-1); } // The server IP and Port memset(&server, 0, sizeof server); server.sin_family = AF_INET; // Use IPv4 server.sin_port = htons(portno); // Server Port struct hostent *hp = gethostbyname(serverIP); memcpy((char*)&server.sin_addr, (char*)hp->h_name, hp->h_length); printf("Sent %s\n", filename); // No need to bind, just send request for file int serverSize = sizeof(server); sendto(sockfd, argv[3], strlen(argv[3]), 0, (struct sockaddr *) &server, serverSize); printf("Waiting for reply\n"); recvfrom(sockfd, buf, MAXBUFLEN-1, 0, (struct sockaddr *) &server, serverSize); buf[numbytes] = '\0'; printf("server sent: %s\n", buf); close(sockfd); } </code></pre> So far the Server just prints out <pre><code>Waiting for data... </code></pre> only once... so its never getting a request. and the Client prints out: <pre><code>./client 8083 127.0.0.1 hello Port: 8083, IP:127.0.0.1, File:hello Sent hello Waiting for reply server sent: </code></pre> Please help, I'm new to the world of C and UDP Sockets. Oh yeah, and I already read Beej's Guide... please don't just post that as an answer.
Tags
<c><sockets><udp>
Title
Whats wrong with my UDP Client Server?
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1. PO
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1. USBernie Perez
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