sockets: Why does server[buffer] > client[message]? + more questions

[edit] Why must server[buffer] > client[message]?

Hi,
My client tries to send 'ping' to my server.
client:

Code:

int main()
{
	int sockfd;
	struct sockaddr_in server_address;
	char server_ip[16];
	char *message = "ping";
	//stuff
	send(sockfd, message, strlen(message) + 1, 0);

server:

Code:

	char buffer[smaller than 8];
	//stuff
	recv(new_fd, buffer, strlen(message);
	printf("%s\n", buffer);

With a buffer smaller than 8 the server only prints a new line, even though I'm only expecting 'ping' + '\0', 5 characters. With 8 or more 'ping' is received and printed succesfully. Is there still some header that needs to be stripped at this point? (or other?)

With

Code:

send(sockfd, message, strlen(message), 0);

without the + 1 the message gets sent and printed, plus some garbage characters. Why is this?
If the entire code is needed, which is not that big, please let me know.

Slightly off-topic:
What do you think about

Code:

if (connect(sockfd, (struct sockaddr *) &servaddr, 
                                                sizeof(servaddr)) < 0) {

                fprintf(stderr, "connect error: %s\n", strerror(errno));
                exit(EXIT_FAILURE);

versus

Code:

if ((connect(sockfd, (struct sockaddr *)&server_address, \
			sizeof server_address)) == -1) {
		perror("Connection error: ");
		exit(EXIT_FAILURE);

? I think the question is how to do propper error handling. I see much examples but do not understand the difference.

Please note that I'm a beginner amongst beginners.
Thanks,
heras

> recv(new_fd, buffer, strlen(message);

should be:

recv(new_fd, buffer, sizeof(buffer));

> without the + 1 the message gets sent and printed, plus some garbage characters. Why is this?

strlen does not count the nul terminating character.

> If the entire code is needed, which is not that big, please let me know.

that would be preferrable.

Hi robwhit, thanks for your reply.

> recv(new_fd, buffer, strlen(message);

Yes, my bad. I forgot to replace that "message" with buffer, intended for clarity. I call them "message" in both the client and the server in my actual program:
[edit] and I missed the sizeof XD. Fixed.
client.c :

Code:

/*
		Socket exercise - Stream client
*/

#include <stdio.h> /* printf, scanf, etc */
#include <stdlib.h> /* ? */
#include <string.h> /* memset() */
#include <sys/types.h> /* socket(), connect(), etc */
#include <sys/socket.h> /* socket(), connect(), etc */
#include <netinet/in.h> /* inet_addr() */
#include <arpa/inet.h> /* inet_addr() */
#include <errno.h> /* perror() */

int main()
{
    int sockfd;
    struct sockaddr_in server_address;
    char server_ip[16];
    char *message = "ping";
    char reply[1024];

    printf("Enter server IP:\n");
    scanf("&#37;15s", server_ip);                       // fix me

    if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
        perror("Socket error: ");
        exit(EXIT_FAILURE);
    }
    server_address.sin_family = AF_INET;
    server_address.sin_port = htons(9999);
    server_address.sin_addr.s_addr = inet_addr(server_ip);
    memset(server_address.sin_zero, '\0', sizeof server_address.sin_zero);
    if ((connect(sockfd, (struct sockaddr *)&server_address, \
            sizeof server_address)) == -1) {
        perror("Connection error: ");
        exit(EXIT_FAILURE);
    }
    send(sockfd, message, strlen(message) + 1, 0);
    recv(sockfd, reply, sizeof(reply), 0);
    printf("%s\n", reply);

    return 0;
}

server.c :

Code:

/*
        Socket exercise - Stream server
*/

#include <stdio.h> /* printf, scanf, etc */
#include <stdlib.h> /* ? */
#include <string.h> /* memset() */
#include <sys/types.h> /* socket(), connect(), etc */
#include <sys/socket.h> /* socket(), connect(), etc */
#include <netinet/in.h> /* inet_addr() */
#include <arpa/inet.h> /* inet_addr() */
#include <errno.h> /* perror() */
#include <unistd.h>

#define PORT 9999
#define BACKLOG 10

int main()
{
    int sockfd, new_fd, yes = 1;
    struct sockaddr_in local_address, remote_address;
    socklen_t sin_size;
    char message[1024];
    char *reply = "pong";

    if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket: ");
        exit(EXIT_FAILURE);
    }
    if ((setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, \
            sizeof(int))) == -1) {
        perror("setsockopt :");
        exit(EXIT_FAILURE);
    }

    local_address.sin_family = AF_INET;
    local_address.sin_port = htons(PORT);
    local_address.sin_addr.s_addr = INADDR_ANY;
    memset(local_address.sin_zero, '\0', sizeof local_address.sin_zero);
    if ((bind(sockfd, (struct sockaddr *)&local_address, \
            sizeof local_address)) == -1) {
        perror("bind: ");
        exit(EXIT_FAILURE);
    }
    if ((listen(sockfd, BACKLOG)) == -1) {
        perror("listen: ");
        exit(EXIT_FAILURE);
    }

    while(1) {
        sin_size = sizeof remote_address;
        if ((new_fd = accept(sockfd, (struct sockaddr *)&remote_address, \
                &sin_size)) == -1) {
            perror("accept: ");
            continue;
        }
        if (!fork()) {
            close(sockfd);
            if (recv(new_fd, message, sizeof(message), 0) == -1) \
                perror("recv: ");
            else {
                printf("%s\n", message);
                send(new_fd, reply, strlen(reply) + 1, 0);
            }
            close(new_fd);
            exit(EXIT_SUCCESS);
        }
        close(new_fd);
    }

    return(EXIT_SUCCESS);
}

recv might not fill up the buffer.

What do recv/send return?

Send() returns 5, recv() returns 0. But I think I'm doing it wrong.

Code:

            if (r = (recv(new_fd, message, sizeof(message), 0) == -1)) \
                perror("recv: ");
            else {
                printf("%s\n", message);
                (s = send(new_fd, reply, strlen(reply) + 1, 0));
            }
            printf("%d\n", s);
            printf("%d\n", r);

[edit] the client returns 5 for both send() and recv()