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Is it possible to use select for packet sockets? I mean whether its necessary for the socket to be connection-based in order to use select function on it properly?
I'm seeing that the behavior of a socket which I got it by the following socket function call:
int socket_fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
is not as I expect. For example, I see that a ping packet which is 60 bytes long when received and read into a 20 bytes length buffer, it waits about a second between each recv function call. I used recvfrom and it didn't help. For this, I ask whether it's correct to use select for a packet socket?
Update
I'm going to include the code to discuss about it:
int MakeBridge(const char *if1, const char *if2)
{
int sock[2];
sock[0] = OpenSocket(if1);
sock[1] = OpenSocket(if2);
int activity;
char buf[20];
const int numSocks = 2;
int nfds = sock[0];
for (int i = 1; i < numSocks; i++)
if (sock[i] > nfds)
nfds = sock[i];
nfds++;
while (true)
{
FD_ZERO(&readfds);
for (int i = 0; i < numSocks; i++)
FD_SET(sock[i], &readfds);
activity = select(nfds, &readfds, NULL, NULL, NULL);
if (activity == -1) // sockets closed
break;
for (int i = 0; i < numSocks; i++)
if (FD_ISSET(_sock[i], &readfds))
{
int len;
CHECK(ioctl(_sock[i], FIONREAD, &len) != -1, "%s", strerror(errno));
printf("socket %d is set\n", i);
printf("total bytes available to read: %d\n", len);
CHECK(len > 0, "");
do
{
int n = min(len, sizeof(buf));
int nbr = recvfrom(_sock[i], buf, n, 0, NULL, NULL);
printf("n %d nbr %d\n", n, nbr);
CHECK(n == nbr, "");
len -= n;
} while (len);
}
}
return 0;
}
Update 2
Not going to segment messages and using large enough buffer makes the code as follows:
// This is a program which is going to make the bridge between two interfaces. brctl is going to be replaced by this program.
#define Uses_CHECK
#define Uses_close
#define Uses_errno
#define Uses_ETH_P_ALL
#define Uses_FD_SET
#define Uses_htons
#define Uses_ifreq
#define Uses_ioctl
#define Uses_printf
#define Uses_signal
#define Uses_sockaddr_ll
#define Uses_socket
#define Uses_strerror
#include <general.dep>
int _sock[2];
int _CtrlCHandler()
{
printf(" terminating...\n");
CHECK(close(_sock[0]) != -1, "");
CHECK(close(_sock[1]) != -1, "");
printf("all sockets closed successfully.\n");
}
void CtrlCHandler(int dummy)
{
_CtrlCHandler();
}
int OpenSocket(const char *ifname)
{
// getting socket
int socket_fd = socket(PF_PACKET, SOCK_RAW/*|SOCK_NONBLOCK*/, htons(ETH_P_ALL));
CHECK(socket_fd != -1, "%s", strerror(errno));
// init interface options struct with the interface name
struct ifreq if_options;
memset(&if_options, 0, sizeof(struct ifreq));
strncpy(if_options.ifr_name, ifname, sizeof(if_options.ifr_name) - 1);
if_options.ifr_name[sizeof(if_options.ifr_name) - 1] = 0;
// enable promiscuous mode
CHECK(ioctl(socket_fd, SIOCGIFFLAGS, &if_options) != -1, "%s", strerror(errno));
if_options.ifr_flags |= IFF_PROMISC;
CHECK(ioctl(socket_fd, SIOCSIFFLAGS, &if_options) != -1, "%s", strerror(errno));
// get interface index
CHECK(ioctl(socket_fd, SIOCGIFINDEX, &if_options) != -1, "%s", strerror(errno));
// bind socket to the interface
struct sockaddr_ll my_addr;
memset(&my_addr, 0, sizeof(my_addr));
my_addr.sll_family = AF_PACKET;
my_addr.sll_ifindex = if_options.ifr_ifindex;
CHECK(bind(socket_fd, (struct sockaddr *)&my_addr, sizeof(my_addr)) != -1, "%s", strerror(errno));
// socket is ready
return socket_fd;
}
int MakeBridge(const char *if1, const char *if2)
{
_sock[0] = OpenSocket(if1);
CHECK_NO_MSG(_sock[0]);
_sock[1] = OpenSocket(if2);
CHECK_NO_MSG(_sock[1]);
printf("sockets %d and %d opened successfully\n", _sock[0], _sock[1]);
fd_set readfds, orig;
int activity;
char buf[1<<16];
signal(SIGINT, CtrlCHandler);
int packetNumber = 0;
const int numSocks = _countof(_sock);
int nfds = _sock[0];
for (int i = 1; i < numSocks; i++)
if (_sock[i] > nfds)
nfds = _sock[i];
nfds++;
FD_ZERO(&orig);
for (int i = 0; i < numSocks; i++)
FD_SET(_sock[i], &orig);
while (true)
{
readfds = orig;
activity = select(nfds, &readfds, NULL, NULL, NULL);
if (activity == -1) // sockets closed
break;
CHECK(activity > 0, "");
for (int i = 0; i < numSocks; i++)
if (FD_ISSET(_sock[i], &readfds))
{
int len = recvfrom(_sock[i], buf, sizeof(buf), MSG_TRUNC, NULL, NULL);
CHECK(len > 0, "");
CHECK(len <= sizeof(buf), "small size buffer");
printf("%10d %d %d\n", ++packetNumber, i, len);
CHECK(sendto(_sock[!i], buf, len, 0, NULL, 0) == len, "");
}
}
return 0;
}
int Usage(int argc, const char *argv[])
{
printf("Usage: %s <if1> <if2>\n", argv[0]);
printf("Bridges two interfaces with the names specified.\n");
return 0;
}
int main(int argc, const char *argv[])
{
if (argc != 3)
return Usage(argc, argv);
CHECK_NO_MSG(MakeBridge(argv[1], argv[2]));
return 0;
}
I am writing a simple Server Client program that exchanges the data. After I write to the socket file, the write doesn't fail or it is not even partial write. but when I check the details of the socket file using ls -l , I still see it's size as zero and server doesn't recieve anything. Can anyone help me out with what I am doing wrong in here??
This is server.c
int main()
{
int socket_fd = 0;
struct sockaddr_un addr;
int result = -1;
char buffer[MAX_BUFFER_SIZE];
printf("Creating a socket\n");
socket_fd = socket(AF_UNIX,SOCK_STREAM,0);
if(socket_fd == -1)
{
perror("SOCKET");
return 0;
}
printf("Socket has been created %d\n",socket_fd);
addr.sun_family = AF_UNIX;
strncpy(addr.sun_path,_SOCKET_PATH,sizeof(addr.sun_path)-1);
printf("PATH : %s\n",addr.sun_path);
if(remove(_SOCKET_PATH) == -1)
{
perror("REMOVE");
return 0;
}
printf("Binding the socket\n");
result = bind(socket_fd,(struct sockaddr *)&addr,sizeof(struct sockaddr_un));
if(result == -1)
{
perror("BIND");
return 0;
}
printf("Binding the socket is done\n");
printf("Listening to the socket\n");
if(listen(socket_fd,1) == -1)
{
perror("Listen");
return 0;
}
if((result = accept(socket_fd,NULL,NULL)) == -1)
{
perror("ACCEPT");
return 0;
}
printf("Connection Accepted\n");
while (1)
{
while (result = read(socket_fd,buffer,sizeof(buffer)-1) > 0)
{
printf("Client said : %s\n",buffer);
}
}
}
This is client.c
int main()
{
int socket_fd = 0;
struct sockaddr_un addr;
int result = -1;
char buffer[MAX_BUFFER_SIZE];
printf("Creating a socket\n");
socket_fd = socket(AF_UNIX,SOCK_STREAM,0);
if(socket_fd == -1)
{
perror("SOCKET");
return 0;
}
printf("Socket has been found %d\n",socket_fd);
addr.sun_family = AF_UNIX;
strncpy(addr.sun_path,_SOCKET_PATH,sizeof(addr.sun_path)-1);
printf("Connecting to the socket\n");
result = connect(socket_fd,(struct sockaddr *)&addr,sizeof(struct sockaddr_un));
if(result == -1)
{
perror("CONNECT");
return 0;
}
printf("The client is connected to the server.\n");
while (1)
{
memset(buffer,0,sizeof(buffer));
scanf("%s",buffer);
printf("DATA WRITTEN %s,%d\n",buffer,strlen(buffer)+1);
result = write(socket_fd,buffer,strlen(buffer)+1);
printf("result = %d\n",result);
sleep(5);
}
}
Thanks for any help!
if((result = accept(socket_fd,NULL,NULL)) == -1)
...
while (result = read(socket_fd,buffer,sizeof(buffer)-1) > 0)
You are trying to read from the server socket (socket_fd). Instead you need to read from the new socket returned by accept, i.e. what you call result in result = accept.... To cite from man accept:
On success, these system calls return a nonnegative integer that is a
file descriptor for the accepted socket. On error, -1 is returned,
and errno is set appropriately.
I am trying to do Socket programming. I've google and looked at problems like mine. However, I can't see to figure out my error.
Whenever I run my code, I get an error in connect() in main in client.c. The error is invalid argument.
Server.c
/* chatroom server */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>
#include <pthread.h>
#include <signal.h>
#define MAX_ROOMS 36
#define MAX_NAME_SIZE 56
#define PORT_NUM 12333
#define MSG_SIZE 8
#define MAX_LOAD 246
#define MAX_CRC 64 //max clients
#define MAX_BUF 256
#define SERVER_IP 32
#define DEBUG 0
struct msg {
int type; //create, join, delete
int length; // length or port num
};
struct chat_room {
int socket_d; //socket descriptor
int port;
pthread_t id; //id of chatroom
char name[MAX_NAME_SIZE];
int clients[MAX_ROOMS]; // used to hold the client's master sockets
};
struct chat_room* findRoom(char* name, struct chat_room* chat){
int iterator;
for(iterator = 0; iterator < MAX_ROOMS; iterator++){
if(strcmp(name, chat[iterator].name) && (chat[iterator].port != 0)) {
return &chat[iterator];
}
}
//if room does not exist
return NULL;
}
struct chat_room* joinServer(int chat_socket, char* name, struct chat_room* chat){
struct chat_room* local_chat = findRoom(name, chat);
int i;
if(local_chat != NULL){ //if the chat exists
for(i= 0; i< MAX_CRC; i++){
if(local_chat->clients[i] == 0)
{
local_chat->clients[i] = chat_socket;
}
return local_chat;
}
}
//if server if full or else error
return NULL;
}
int createResponse(int chat_socket, int new_port_num, int type){
struct msg temp;
char temp_buff[MAX_LOAD];
memset(temp_buff, 0, MAX_LOAD);
temp.type = type;
temp.length = new_port_num;
memcpy(temp_buff, &temp, sizeof(temp));
write(chat_socket, temp_buff, MSG_SIZE);
return 0;
}
int joinResponse(int chat_socket, int new_port_num){
struct msg temp;
char temp_buff[MAX_LOAD];
memset(temp_buff, 0, MAX_LOAD);
temp.type = 11;
temp.length = new_port_num;
memcpy(temp_buff, &temp, sizeof(temp));
write(chat_socket, temp_buff, MSG_SIZE);
return 0;
}
int deleteResponse(int chat_socket, struct chat_room* chat){
struct msg temp;
char temp_buff[MAX_LOAD];
int i;
memset(temp_buff, 0, MAX_LOAD);
temp.type = 12;
memcpy(temp_buff, &temp, sizeof(temp));
for(i=0; i<MAX_CRC; i++){
if((chat->clients[i] != chat_socket) && (chat->clients[i] != 0))
write(chat->clients[i],temp_buff, MSG_SIZE);
}
return 0;
}
struct chat_room* addRoom(int chat_socket, char* name, struct chat_room* chat){
int socket_d;
int i;
struct sockaddr_in sock;
static int port = PORT_NUM;
memset(&sock, 0, sizeof(sock));
int temp = -1;
for(i = 0; i<MAX_ROOMS; i++){
if((strcmp(chat[i].name, name) == 0) && (chat[i].port != 0)){
createResponse(chat_socket, chat[i].port, 15);
return NULL;
}
else if((chat[i].port == 0) && (temp== -1)){
temp = i;
}
}
if(temp == -1){
return NULL;
}
socket_d = socket(AF_INET, SOCK_STREAM, 0);
if(socket_d == -1 && DEBUG){
perror("Error creating chatroom socket");
return NULL;
}
sock.sin_family = AF_INET;
port++;
sock.sin_port = htons(port);
if(bind(socket_d, (struct sockaddr*)&sock, sizeof(struct sockaddr_in)) == -1){
perror("error in binding ");
return NULL;
}
chat[temp].socket_d = socket_d;
chat[temp].port = port;
strcpy(chat[temp].name, name);
return &chat[temp];
}
void* chat_room_main(void* chat_room_cluster){
char buf[MAX_LOAD];
int socket_d, chat_socket;
int temp; //temp_fd
int read_val;
int num_clients = 0;
int i;
int clients[MAX_CRC];
fd_set allfd, modfd;
struct chat_room chat_room_para;
memcpy(&chat_room_para, (struct chat_room*)chat_room_cluster, sizeof(struct chat_room));
free(chat_room_cluster);
memset(clients, 0, sizeof(int)*MAX_CRC);
socket_d = chat_room_para.socket_d;
listen(socket_d, 1);
FD_ZERO(&allfd);
FD_SET(socket_d, &allfd);
printf("New Chatroom Started\n");
while(1){
modfd = allfd;
select(FD_SETSIZE, &modfd, NULL, NULL, NULL);
for(temp = 0; temp < FD_SETSIZE; temp++){
if(FD_ISSET(temp, &modfd)){
memset(buf, 0, sizeof(buf));
if(temp == socket_d) {
chat_socket = accept(socket_d, NULL, NULL);
FD_SET(chat_socket, &allfd);
// find an empty spot to add the chat room
for(i = 0; i<MAX_CRC; i++) {
if(clients[i] == 0){
clients[i] = chat_socket;
break;
}
}
sprintf(buf, "Number of people in chatroom: %d", num_clients);
write(chat_socket, buf, strlen(buf));
num_clients++;
}
else{
if(read_val = read(temp, buf, MAX_LOAD) > 0){
for(i = 0; i< MAX_CRC; i++){
if((clients[i] != temp) && (clients[i] != 0)){
write(clients[i], buf, read_val);
}
}
}
else if(read_val <= 0) {
FD_CLR(temp, &allfd);
for(i = 0; i<MAX_CRC; i++){
if(clients[i] == temp)
clients[i] = 0;
}
num_clients--;
close(chat_socket);
}
}
}
}
}
}
int main(int argc, char* argv[]){
int server_socket, chat_socket; //file descriptors for server and chat
int temp; //tempfd
int i, j;
char server_ip[SERVER_IP];
char buf[MAX_BUF];
char msg_buf[MSG_SIZE];
fd_set allfd, modfd;
struct sockaddr_in sock;
struct hostent* host_name;
struct chat_room chatrooms[MAX_ROOMS];
memset(chatrooms, '\0', sizeof(struct chat_room)* MAX_ROOMS);
memset(&sock, '\0', sizeof(sock));
server_socket = socket(AF_INET, SOCK_STREAM, 0);
if(server_socket == -1){
perror("Error creating socket");
return -1;
}
sock.sin_family = AF_INET;
sock.sin_port = htons(PORT_NUM);
sock.sin_addr.s_addr = INADDR_ANY;
if((bind(server_socket, (struct sockaddr*)&sock, sizeof(struct sockaddr_in))) == -1){
perror("Error in bind()");
return -1;
}
listen(server_socket, 1);
FD_ZERO(&allfd);
FD_SET(server_socket, &allfd);
FD_SET(0, &allfd);
printf("\n*******Chatroom Server*******");
while(1){
modfd = allfd;
select(FD_SETSIZE, &modfd, NULL, NULL, NULL);
for(temp = 0; temp < FD_SETSIZE; temp++) {
if(FD_ISSET(temp, &modfd)) {
switch(temp){
case 0:
break;
default:
if(temp == server_socket){
chat_socket = accept(server_socket, NULL, NULL);
}
else{
char msg_buf[MSG_SIZE];
char buf[MAX_LOAD];
char name[MAX_LOAD];
struct msg temp_message;
struct chat_room* local_chat = NULL;
void* (*init_chatroom)() = &chat_room_main;
void* thread_args;
pthread_attr_t attr;
pthread_t tid;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
memset(buf, 0, sizeof(buf));
memset(msg_buf, 0, sizeof(msg_buf));
msg_buf[19]= 0;
int read_val = read(temp, msg_buf, MSG_SIZE);
if(read_val > 0){
memcpy(&temp_message, msg_buf, sizeof(temp_message));
read(temp, buf, temp_message.length - sizeof(temp_message));
memcpy(name, buf, temp_message.length - sizeof(temp_message));
if(temp_message.type == 0) {//if create
local_chat = addRoom(temp, name, chatrooms);
if(local_chat != NULL){
thread_args = (void*)malloc(sizeof(struct chat_room));
memcpy((struct chat_room*) thread_args, local_chat, sizeof(struct chat_room));
pthread_create(&tid, &attr, init_chatroom, thread_args);
local_chat->id = tid;
createResponse(temp, local_chat->port, 10);
}
}
else if(temp_message.type == 1){ //join
local_chat = joinServer(temp, name, chatrooms);
if(local_chat != NULL){
joinResponse(temp, local_chat->port);
}
}
else if(temp_message.type == 2){ //delete
local_chat = findRoom(name, chatrooms);
printf("Deleting Room\n");
if(local_chat != NULL) {
local_chat->port = 0;
close(local_chat->socket_d);
deleteResponse(temp, local_chat);
for(j = 0; j<MAX_CRC; j++){
if(local_chat->clients[j]!=0) {
FD_CLR(local_chat->clients[j], &modfd);
local_chat->clients[j] = 0;
}
}
pthread_cancel(local_chat->id);
}
}
}
else if(read_val <= 0){
FD_CLR(temp, &allfd);
close(temp);
}
}
}
}
}
}
return 0;
}
Client.c
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>
#include <pthread.h>
#define PORT_NUM 12333
#define MSG_SIZE 8
#define MAX_LOAD 246
#define MAX_BUF 256
#define SERVER_IP 32
struct msg {
int type;
int length;
};
struct thread_para {
int port;
struct hostent* host_name;
};
int sendCmd(int chat_socket, char* buf, int type){ //function for sending the command
struct msg temp;
char temp_buf[MAX_LOAD];
char name[MAX_LOAD];
int iterator;
if(type == 0){
iterator = 6;
}
else if(type == 1){
iterator = 4;
}
else if(type == 2){
iterator = 6;
}
for(; iterator < strlen(buf); iterator++){
if(buf[iterator] == ' ') {
continue;
}
else{
break;
}
}
strcpy(name, buf+iterator);
memset(temp_buf, 0, MAX_LOAD);
temp.type = type;
temp.length = sizeof(temp)+strlen(name)+1; //for \0
memcpy(temp_buf, &temp, sizeof(temp));
memcpy(temp_buf+sizeof(temp), name, strlen(name)+1);
write(chat_socket, temp_buf, temp.length);
return 0;
}
void* connectChat(int port_num, struct hostent* host_name, int master){
char buf[MAX_BUF];
char temp_buf[MAX_BUF];
int chat_socket;
int i;
int input;
int temp; //temp fd
fd_set allfd, modfd;
struct sockaddr_in sock;
printf("Successfully Joined Room\n");
memset(buf, 0, sizeof(buf));
memset(&sock, 0, sizeof(sock));
sock.sin_family = AF_INET;
sock.sin_port = htons(port_num);
memcpy((char*)&sock.sin_addr.s_addr, host_name->h_addr, host_name->h_length);
chat_socket = socket(AF_INET, SOCK_STREAM, 0);
if(chat_socket == -1){
perror("Error in creation");
return NULL;
}
if(connect(chat_socket, (struct sockaddr*)&sock, sizeof(struct sockaddr)) < 0 ){
perror("Error in connection");
return NULL;
}
FD_ZERO(&allfd);
FD_SET(chat_socket, &allfd);
FD_SET(0, &allfd);
FD_SET(master, &allfd);
while(1) {
modfd = allfd;
select(FD_SETSIZE, &modfd, NULL, NULL, NULL);
for(temp = 0; temp< FD_SETSIZE; temp++){
memset(buf, 0, sizeof(buf));
memset(temp, 0, sizeof(buf));
if(temp == 0) { //reading from standard in
input = read(0, buf, MAX_BUF);
buf[input-1] = '\0'; //add termination to end
write(chat_socket, buf, strlen(buf));
}
else if(temp == chat_socket){
input = read(0, buf, MAX_BUF);
buf[input] = '\0';
memcpy(temp, buf, input);
//display message
printf("%s \n", temp_buf);
}
else if(temp == master){
struct msg temp_message;
input = read(temp, buf, MSG_SIZE);
memcpy(&temp_message, buf, MSG_SIZE);
if(temp_message.type == 12){
printf("Chatroom has been deleted, Shutting down chatroom\n");
return NULL;
}
}
}
}
return 0;
}
int main(int argc, char* argv[]){
char buf[MAX_BUF];
int chat_socket;
int i;
int input;
int temp; //temp fd
int accept_input = 1; // take input for stdin to create a chat thread
fd_set allfd, modfd;
char server_ip[SERVER_IP];
struct hostent* host_name;
struct sockaddr_in sock;
struct msg temp_message;
pthread_attr_t tattr;
pthread_t tid;
if(argc < 2) {
printf("Please try ./crc <server IP> \n");
return -1;
}
pthread_attr_init(&tattr);
pthread_attr_setdetachstate(&tattr, PTHREAD_CREATE_DETACHED);
memset(&sock, '\0', sizeof(sock));
sock.sin_family = AF_INET;
sock.sin_port = htons(PORT_NUM);
strcpy(server_ip ,argv[1]);
if((host_name = (struct hostent*)gethostbyname(server_ip)) == NULL){
perror("failed to get host name");
return -1;
}
memcpy((char*)&sock.sin_addr.s_addr, host_name->h_addr, host_name->h_length);
chat_socket = socket(AF_INET, SOCK_STREAM, 0);
if(chat_socket == -1){
perror("Error creating socket");
return -1;
}
if((connect(chat_socket, (struct sockaddr*)&sock, sizeof(sock))) < 0) {
perror("Error connecting");
return -1;
}
FD_ZERO(&allfd); /* first, clear the allfd set */
FD_SET(chat_socket, &allfd); /* adding client to the set */
FD_SET(0, &allfd);
printf("*****Welcome to the Chatroom*****\n");
while(1){
modfd = allfd;
select(FD_SETSIZE, &modfd, NULL, NULL, NULL);
for(temp = 0; temp < FD_SETSIZE; temp++){
if(FD_ISSET(temp, &modfd)){
if(temp == 0){
input = read(0, buf, MAX_BUF);
buf[input-1] = '\0'; //remove \n inserts termination
if((strncasecmp(buf, "create ", 7) == 0)) {
sendCmd(chat_socket, buf, 0);
}
else if((strncasecmp(buf, "join ", 5) == 0)) {
sendCmd(chat_socket, buf, 1);
}
else if((strncasecmp(buf, "delete ", 7)==0)){
sendCmd(chat_socket, buf, 2);
}
else
{
printf("Enter a valid command: create <Room_name>, join <Room_name>, delete <Room_name>\n");
}
}
else if(temp == chat_socket){
input = read(temp, buf, MSG_SIZE);
memcpy(&temp_message, buf, sizeof(temp_message));
if(temp_message.type == 10) {
printf("Created Chatroom\n");
}
else if(temp_message.type == 11){
connectChat(temp_message.length, host_name, chat_socket);
fflush(stdin);
}
else if(temp_message.type == 15) {
printf("Chatroom exits. Type join <Room_name> to join\n");
}
}
}
}
}
close(chat_socket);
return 0;
}
I gave both sets of code just in case it was need. The program is designed to create multiple chat rooms.
invalid argument is the EINVAL error code, which in the context of connect() means:
An invalid argument was detected (e.g., address_len is not valid for the address family, the specified address family is invalid).
You have multiple calls to connect() in your client code (why?), but you did not indicate which call is the one that is failing. In connectChat() at least, sizeof(struct sockaddr) should be sizeof(struct sockaddr_in) instead, or better sizeof(sock), like you do in main().
Also, if either connect() fails, you are leaking the socket returned by socket(). You need to close() it.
Also, gethostbyname() is deprecated, you should be using getaddrinfo() instead. You are creating IPv4 sockets, which only work with IPv4 addresses. You are not checking if gethostbyname() actually returns an IPv4 address (host_name->h_addr_type == AF_INET) before copying the address bytes into your sock variable. At least with getaddrinfo(), you can restrict the output to IPv4 addresses only. You don't have that option with gethostbyname().
Since you're looking for a way to figure out your error, I'll suggest you to use the following Makefile:
CFLAGS=-Wall -g -O2
CC=gcc
LDFLAGS=-lpthread
all: Server Client
Server: Server.c
Client: Client.c
After running make command you'll see a lot of warnings. Some of them:
Server.c: In function ‘createResponse’:
Server.c:81:5: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
write(chat_socket, temp_buff, MSG_SIZE);
^
Server.c: In function ‘chat_room_main’:
Server.c:237:25: warning: ‘chat_socket’ may be used uninitialized in this function [-Wmaybe-uninitialized]
close(chat_socket);
^
Server.c: In function ‘main’:
Server.c:319:36: warning: array subscript is above array bounds [-Warray-bounds]
msg_buf[19]= 0;
Client.c: In function ‘connectChat’:
Client.c:113:20: warning: passing argument 1 of ‘memset’ makes pointer from integer without a cast
memset(temp, 0, sizeof(buf));
^
So just try to fix these warnings. I mean all of them.
so... context: I'm doing a layer 2 protocol for flexible forwarding in vehicular environment (for now my testbed is in virtual machines), this should take in consideration a different number of interfaces (for multihoming) and multihop.
So what I have:
A way of broadcasting hop-by-hop the service provider.
What I'm triyng to do:
A way to register a session all the way from the client to the provider (And here is the problem)
Problem: I have two types of packets
1st is listened correctly and data payload starts with a 1
2nd for some reason is not detected but I can see the packet is sent and correct with tcpdump
Since I have to register in the application the interface where the connection is made I used select() which seems to be part of the problem since I only guessed how it was used and I'm kind of in the dark about this.
UPDATED v3:
Okay so as soon as I removed most of the stuff about only sending on a specific interface all the stuff worked perfectly (I still need to clean this code... it's kind of messy). Here is code if someone is interested:
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <time.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <ifaddrs.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <net/ethernet.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <netinet/in.h>
#define ETH_P_CUSTOM 0x0801 /* EtherType of Current Used Protocol*/
#define BUF_SIZE 1024
typedef enum {
false, true
} Bool; /* Boolean Definition*/
typedef struct Stat {
uint8_t maxSocket; /*Number of sockets to use in receive*/
uint8_t nInterfaces; /*Number of interfaces owned by this machine*/
uint8_t nSession; /*Number of Sessions Known in the linked list*/
uint8_t upMac[ETH_ALEN]; /*MAC of this host upstream parent*/
uint8_t nHops; /*Hops to Provider*/
char ifName[IF_NAMESIZE + 1]; /*Interface to Provider*/
} Stat;
typedef struct Node {
uint64_t session; /*Client Session*/
uint8_t nextHop[ETH_ALEN]; /*Next-Hop to Client*/
char ifName[IF_NAMESIZE + 1]; /*Outgoing Interface that connects to Next-Hop*/
struct Node * next; /*Next Session*/
} Node;
typedef struct ifNode {
uint8_t ifIndex; /*Interface index*/
uint8_t sock; /*Index in array of sockets*/
uint8_t mac[ETH_ALEN]; /*Interface MAC*/
char ifName[IF_NAMESIZE + 1]; /*Interface Name*/
struct ifNode * next; /*Next Session*/
} ifNode;
Stat * op; /* Variable which tracks status of certain structures/variables*/
Node * first = NULL, *last = NULL; /* Edges of linked list */
ifNode * iffirst = NULL, *iflast = NULL; /* Edges of interface linked list */
int cargc;
char **cargv;
int receiveP();
int broadServ();
int announceSelf();
Node* create(uint64_t sess, uint8_t n[ETH_ALEN], char interface[IF_NAMESIZE]);
void insert_node(Node * p);
Node* search(uint64_t session);
void update(uint64_t session, Node * p);
ifNode* createif(uint8_t idx, uint8_t sock, uint8_t ifmac[ETH_ALEN],
char interface[IF_NAMESIZE]);
void insert_ifnode(ifNode * p);
ifNode* searchif(uint8_t idx, uint8_t mode);
void updateif(uint8_t idx, ifNode * p);
void display();
void displayif();
void ctrlcoverride(int sig) {
printf("\nCtrl-C - Signal Caught - Exiting\n\n");
printf(
"Current Upstream MAC: %02x:%02x:%02x:%02x:%02x:%02x - NHops : %u - At Interface %s\n\n",
op->upMac[0], op->upMac[1], op->upMac[2], op->upMac[3],
op->upMac[4], op->upMac[5], op->nHops, op->ifName);
display();
exit(EXIT_SUCCESS);
}
Node* create(uint64_t sess, uint8_t n[ETH_ALEN], char interface[IF_NAMESIZE]) {
Node * new = (Node *) malloc(sizeof(Node));
if (new == NULL) {
printf("Could not create new node\n");
return NULL;
} else {
strcpy(new->ifName, interface);
new->session = sess;
int i;
for (i = 0; i < ETH_ALEN; i++)
new->nextHop[i] = n[i];
new->next = NULL;
return new;
}
}
ifNode* createif(uint8_t idx, uint8_t sock, uint8_t ifmac[ETH_ALEN],
char interface[IF_NAMESIZE]) {
ifNode * new = (ifNode *) malloc(sizeof(ifNode));
if (new == NULL) {
printf("Could not create new interface node\n");
return NULL;
} else {
new->ifIndex = idx;
new->sock = sock;
strcpy(new->ifName, interface);
int i;
for (i = 0; i < ETH_ALEN; i++)
new->mac[i] = ifmac[i];
new->next = NULL;
return new;
}
}
void insert_node(Node * p) {
if (first == last && last == NULL) {
first = last = p;
first->next = NULL;
last->next = NULL;
} else {
last->next = p;
last = last->next;
last->next = NULL;
}
}
void insert_ifnode(ifNode * p) {
if (iffirst == iflast && iflast == NULL) {
iffirst = iflast = p;
iffirst->next = NULL;
iflast->next = NULL;
} else {
iflast->next = p;
iflast = iflast->next;
iflast->next = NULL;
}
}
Node* search(uint64_t session) {
if (first == last && last == NULL) {
return NULL;
} else {
Node * temp;
for (temp = first; temp != NULL; temp = temp->next) {
if (temp->session == session) {
return temp;
}
}
return NULL;
}
}
ifNode* searchif(uint8_t idx, uint8_t mode) {
if (iffirst == iflast && iflast == NULL) {
return NULL;
} else {
ifNode * temp;
for (temp = iffirst; temp != NULL; temp = temp->next) {
if (temp->ifIndex == idx && mode == 0) {
return temp;
} else if (temp->sock == idx && mode == 1) {
return temp;
}
}
return NULL;
}
}
void update(uint64_t session, Node * p) {
if (first == last && last == NULL) {
return;
} else {
Node * temp;
for (temp = first; temp != NULL; temp = temp->next) {
if (temp->session == session) {
strcpy(temp->ifName, p->ifName);
temp->next = p->next;
int i;
for (i = 0; i < ETH_ALEN; i++)
temp->nextHop[i] = p->nextHop[i];
return;
}
}
}
}
void updateif(uint8_t idx, ifNode * p) {
if (iffirst == iflast && iflast == NULL) {
return;
} else {
ifNode * temp;
for (temp = iffirst; temp != NULL; temp = temp->next) {
if (temp->ifIndex == idx) {
strcpy(temp->ifName, p->ifName);
temp->sock = p->sock;
temp->next = p->next;
int i;
for (i = 0; i < ETH_ALEN; i++)
temp->mac[i] = p->mac[i];
return;
}
}
}
}
void display() {
Node * temp = first;
while (temp != NULL) {
printf("Session %" PRIu64 " Through %s - NextHop at ", temp->session,
temp->ifName);
int i;
for (i = 0; i < ETH_ALEN; i++)
printf("%02x ", temp->nextHop[i]);
printf("\n");
temp = temp->next;
}
}
void displayif() {
ifNode * temp = iffirst;
while (temp != NULL) {
printf("Interface Index %u Socket Number %u - Name %s with MAC: ",
temp->ifIndex, temp->sock, temp->ifName);
int i;
for (i = 0; i < ETH_ALEN; i++)
printf("%02x ", temp->mac[i]);
printf("\n");
temp = temp->next;
}
}
uint8_t counter() {
Node * temp = first;
uint8_t counter = 0;
while (temp != NULL) {
counter++;
temp = temp->next;
}
return counter;
}
fd_set rfds;
int rec;
int main(int argc, char **argv) {
setbuf(stdout, NULL);
signal(SIGINT, ctrlcoverride);
cargc = argc;
cargv = argv;
/*Setting Base Variables to Initial Values*/
op = (Stat*) malloc(sizeof(Stat));
op->nSession = 0;
memset(op->ifName, 0, IF_NAMESIZE);
op->maxSocket = 0;
op->nHops = UINT8_MAX - 1;
int i;
for (i = 0; i < ETH_ALEN; i++) {
op->upMac[i] = 0x00;
}
memset(&rfds, 0, sizeof(fd_set));
FD_ZERO(&rfds);
if (argc != 2) {
printf("USAGE: sudo %s {provider|node|nodekey}\n", cargv[0]);
exit(EXIT_FAILURE);
} else if (!(strcmp(cargv[1], "provider") == 0
|| strcmp(cargv[1], "node") == 0 || strcmp(cargv[1], "nodekey") == 0)) {
printf("USAGE: sudo %s {provider|node|nodekey}\n", cargv[0]);
exit(EXIT_FAILURE);
}
if (strcmp(cargv[1], "nodekey") == 0) {
srand(time(NULL));
uint8_t myArray[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
insert_node(
create((uint64_t) (100 * ((float) rand() / RAND_MAX)), myArray,
"SOURCE"));
}
struct ifaddrs *ifaddr, *ifa;
if (getifaddrs(&ifaddr) == -1) {
perror("getifaddrs");
exit(EXIT_FAILURE);
}
for (ifa = ifaddr, op->nInterfaces = 0; ifa != NULL; ifa = ifa->ifa_next) {
if (ifa->ifa_addr == NULL)
continue;
if (ifa->ifa_addr->sa_family == AF_PACKET
&& strncmp(ifa->ifa_name, "lo", strlen("lo")) != 0
&& strncmp(ifa->ifa_name, "tap", strlen("tap")) != 0) {
op->nInterfaces++;
}
}
rec = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_CUSTOM));
int sockopt;
char ifName[IFNAMSIZ];
struct ifreq ifr;
for (i = 1, ifa = ifaddr; ifa != NULL;
ifa = ifa->ifa_next, i++) {
if (ifa->ifa_addr == NULL)
continue;
if (ifa->ifa_addr->sa_family == AF_PACKET
&& strncmp(ifa->ifa_name, "lo", strlen("lo")) != 0
&& strncmp(ifa->ifa_name, "tap", strlen("tap")) != 0) {
uint8_t sock;
if ((sock = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_CUSTOM)))
== -1) {
printf("socket() error: %u - %s\n", errno, strerror(errno));
return EXIT_FAILURE;
}
if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &sockopt,
sizeof sockopt) == -1) {
printf("SO_REUSEADDR error: %u - %s\n", errno, strerror(errno));
close(sock);
return EXIT_FAILURE;
}
memset(&ifr, 0, sizeof(struct ifreq));
ifr.ifr_ifindex = i;
strcpy(ifr.ifr_name, ifa->ifa_name);
if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifa->ifa_name,
IF_NAMESIZE) == -1) {
printf("SO_BINDTODEVICE error: %u - %s\n", errno,
strerror(errno));
close(sock);
return EXIT_FAILURE;
}
struct sockaddr_ll sll;
sll.sll_family = AF_PACKET;
sll.sll_ifindex = i;
sll.sll_protocol = htons(ETH_P_CUSTOM);
if ((bind(sock, (struct sockaddr *) &sll, sizeof(sll))) == -1) {
perror("Error binding raw socket to interface\n");
exit(-1);
}
if ((ioctl(sock, SIOCGIFHWADDR, &ifr)) != 0) {
printf("SIOCGIFHWADDR error: %u - %s\n", errno,
strerror(errno));
return EXIT_FAILURE;
}
int j;
uint8_t ifmac[ETH_ALEN];
for (j = 0; j < ETH_ALEN; j++) {
ifmac[j] = (uint8_t) (ifr.ifr_hwaddr.sa_data)[j];
}
FD_SET(sock, &rfds);
op->maxSocket = (op->maxSocket < sock) ? sock : op->maxSocket;
insert_ifnode(createif(i, sock, ifmac, ifr.ifr_name));
}
}
displayif();
if (strcmp(cargv[1], "provider") == 0) {
struct ifreq if_mac; // interface
char * interface = "eth1";
int sockfd;
if ((sockfd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_CUSTOM))) == -1) {
printf("socket() error: %u - %s\n", errno, strerror(errno));
return EXIT_FAILURE;
}
memset(&if_mac, 0, sizeof(struct ifreq));
strncpy(if_mac.ifr_name, interface, IFNAMSIZ - 1);
if ((ioctl(sockfd, SIOCGIFHWADDR, &if_mac)) != 0) {
printf("SIOCGIFHWADDR error: %u - %s\n", errno, strerror(errno));
return EXIT_FAILURE;
}
int i;
for (i = 0; i < ETH_ALEN; i++)
op->upMac[i] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[i];
op->nHops = 0;
close(sockfd);
}
freeifaddrs(ifaddr);
int stat = 0;
while (1) {
if (strcmp(cargv[1], "provider") == 0) {
if ((stat = receiveP()) != 0)
return stat;
if ((stat = broadServ()) != 0)
return stat;
display();
usleep(100000);
} else if (strcmp(cargv[1], "node") == 0
|| strcmp(cargv[1], "nodekey") == 0) {
if ((stat = receiveP()) != 0)
return stat;
if ((stat = announceSelf()) != 0){
return stat;
}
if ((stat = broadServ()) != 0)
return stat;
display();
usleep(100000);
}
}
ifNode * temp = iffirst;
while (temp != NULL) {
close(temp->sock);
temp = temp->next;
}
exit(stat);
}
int receiveP() {
int stat = 0;
struct ifreq ifr;
struct sockaddr saddr;
long unsigned int numbytes = 0;
char buf[BUF_SIZE];
memset(buf, 0, BUF_SIZE);
struct ether_header *eh = (struct ether_header *) buf;
unsigned int saddr_size = sizeof saddr;
struct timeval tv;
tv.tv_sec = 3; /* 3 Secs Timeout */
tv.tv_usec = 0;
setsockopt(rec, SOL_SOCKET, SO_RCVTIMEO, (char *) &tv,
sizeof(struct timeval));
numbytes = recvfrom(rec, buf, BUF_SIZE, 0, &saddr, &saddr_size);
int len;
int ntable;
switch (buf[sizeof(struct ether_header)]) {
case 1:
if (buf[sizeof(struct ether_header) + 1] < op->nHops) {
op->upMac[0] = eh->ether_shost[0];
op->upMac[1] = eh->ether_shost[1];
op->upMac[2] = eh->ether_shost[2];
op->upMac[3] = eh->ether_shost[3];
op->upMac[4] = eh->ether_shost[4];
op->upMac[5] = eh->ether_shost[5];
op->nHops = buf[sizeof(struct ether_header) + 1] + 1;
memset(&ifr, 0, sizeof(struct ifreq));
memset(&ifr.ifr_name, 0, IF_NAMESIZE);
printf(
"Server %u Hops Away - Through %02x:%02x:%02x:%02x:%02x:%02x At Interface %s\n",
op->nHops, eh->ether_shost[0], eh->ether_shost[1],
eh->ether_shost[2], eh->ether_shost[3], eh->ether_shost[4],
eh->ether_shost[5], op->ifName);
printf("\n\n");
}
break;
case 2:
len = sizeof(struct ether_header) + 1;
ntable = buf[len++];
int j;
for (j = 0; j < ntable; j++, len++) {
if (search(buf[len]) == NULL) {
insert_node(create(buf[len], eh->ether_shost, ""));
}
}
break;
}
return stat;
}
int broadServ() {
int stat = 0;
int tx_len = 0;
char sendbuf[BUF_SIZE];
char ifName[IF_NAMESIZE - 1];
struct ether_header *eh = (struct ether_header *) sendbuf;
struct sockaddr_ll socket_address;
int i;
struct ifreq ifr, if_mac;
ifNode * temp = iffirst;
while (temp != NULL) {
/* Get the index of the interface to send on */
memset(&ifr, 0, sizeof(struct ifreq));
ifr.ifr_ifindex = temp->ifIndex;
if (ioctl(temp->sock, SIOCGIFNAME, &ifr) < 0)
perror("SIOCGIFINDEX");
memset(ifName, 0, IF_NAMESIZE - 1);
strncpy(ifName, ifr.ifr_name, IF_NAMESIZE - 1);
/* Get the MAC address of the interface to send on */
memset(&if_mac, 0, sizeof(struct ifreq));
strncpy(if_mac.ifr_name, ifName, IFNAMSIZ - 1);
if (ioctl(temp->sock, SIOCGIFHWADDR, &if_mac) < 0)
perror("SIOCGIFHWADDR");
if (((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[0] == 0x00
&& ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[1] == 0x00
&& ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[2] == 0x00
&& ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[3] == 0x00
&& ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[4] == 0x00
&& ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[5] == 0x00)
continue;
memset(sendbuf, 0, BUF_SIZE);
/* Ethernet header */
eh->ether_shost[0] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[0];
eh->ether_shost[1] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[1];
eh->ether_shost[2] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[2];
eh->ether_shost[3] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[3];
eh->ether_shost[4] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[4];
eh->ether_shost[5] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[5];
eh->ether_dhost[0] = 0xff;
eh->ether_dhost[1] = 0xff;
eh->ether_dhost[2] = 0xff;
eh->ether_dhost[3] = 0xff;
eh->ether_dhost[4] = 0xff;
eh->ether_dhost[5] = 0xff;
/* Ethertype field */
eh->ether_type = htons(ETH_P_CUSTOM);
tx_len = sizeof(struct ether_header);
/* Packet data */
sendbuf[tx_len++] = 1;
sendbuf[tx_len++] = op->nHops; //+1;
/* Index of the network device */
socket_address.sll_ifindex = temp->ifIndex;
/* Address length*/
socket_address.sll_halen = ETH_ALEN;
/* Destination MAC */
socket_address.sll_addr[0] = 0xff;
socket_address.sll_addr[1] = 0xff;
socket_address.sll_addr[2] = 0xff;
socket_address.sll_addr[3] = 0xff;
socket_address.sll_addr[4] = 0xff;
socket_address.sll_addr[5] = 0xff;
/* Send packet */
if (sendto(temp->sock, sendbuf, tx_len, 0,
(struct sockaddr*) &socket_address, sizeof(struct sockaddr_ll))
< 0)
printf("Send failed\n");
temp = temp->next;
}
return stat;
}
int announceSelf() {
if (op->upMac[0] == 0x00 && op->upMac[1] == 0x00 && op->upMac[2] == 0x00
&& op->upMac[3] == 0x00 && op->upMac[4] == 0x00
&& op->upMac[5] == 0x00)
return EXIT_SUCCESS;
int stat = 0;
int tx_len = 0;
char sendbuf[BUF_SIZE];
char ifName[IF_NAMESIZE - 1];
struct ether_header *eh = (struct ether_header *) sendbuf;
struct sockaddr_ll socket_address;
int i;
struct ifreq ifr, if_mac;
ifNode * temp = iffirst;
while (temp != NULL) {
memset(&ifr, 0, sizeof(struct ifreq));
ifr.ifr_ifindex = temp->ifIndex;
if (ioctl(temp->sock, SIOCGIFNAME, &ifr) < 0)
perror("SIOCGIFINDEX");
memset(ifName, 0, IF_NAMESIZE - 1);
strncpy(ifName, ifr.ifr_name, IF_NAMESIZE - 1);
/* Get the MAC address of the interface to send on */
memset(&if_mac, 0, sizeof(struct ifreq));
strncpy(if_mac.ifr_name, ifName, IFNAMSIZ - 1);
if (ioctl(temp->sock, SIOCGIFHWADDR, &if_mac) < 0)
perror("SIOCGIFHWADDR");
if (((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[0] == 0x00
&& ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[1] == 0x00
&& ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[2] == 0x00
&& ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[3] == 0x00
&& ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[4] == 0x00
&& ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[5] == 0x00)
continue;
memset(sendbuf, 0, BUF_SIZE);
/* Ethernet header */
eh->ether_shost[0] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[0];
eh->ether_shost[1] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[1];
eh->ether_shost[2] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[2];
eh->ether_shost[3] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[3];
eh->ether_shost[4] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[4];
eh->ether_shost[5] = ((uint8_t *) &if_mac.ifr_hwaddr.sa_data)[5];
eh->ether_dhost[0] = op->upMac[0];
eh->ether_dhost[1] = op->upMac[1];
eh->ether_dhost[2] = op->upMac[2];
eh->ether_dhost[3] = op->upMac[3];
eh->ether_dhost[4] = op->upMac[4];
eh->ether_dhost[5] = op->upMac[5];
/* Ethertype field */
eh->ether_type = htons(ETH_P_CUSTOM);
tx_len = sizeof(struct ether_header);
/* Packet data */
sendbuf[tx_len++] = 2;
sendbuf[tx_len++] = counter();
Node *temp1 = first;
for (; temp1 != NULL; temp1 = temp1->next) {
sendbuf[tx_len++] = temp1->session;
}
socket_address.sll_ifindex = temp->ifIndex;
/* Address length*/
socket_address.sll_halen = ETH_ALEN;
/* Destination MAC */
socket_address.sll_addr[0] = op->upMac[0];
socket_address.sll_addr[1] = op->upMac[1];
socket_address.sll_addr[2] = op->upMac[2];
socket_address.sll_addr[3] = op->upMac[3];
socket_address.sll_addr[4] = op->upMac[4];
socket_address.sll_addr[5] = op->upMac[5];
/* Send packet */
if (sendto(temp->sock, sendbuf, tx_len, 0,
(struct sockaddr*) &socket_address, sizeof(struct sockaddr_ll))
< 0)
printf("Send failed\n");
temp = temp->next;
}
return stat;
}
So to test this you can have VM with linux connected like this (for example):
Provider ----- Node ----- Node ----- Nodekey
I still had a problem when creating multiple sessions, i wasn't incrementing the buffer when reading and I was reading multiple times the same position. Now it's working good
OK, let's begin with the easiest recommendations but I'm not sure this is going to resolve the problem at once. I did a system like this many years ago for different boards with different processor architectures communicating with each other. All the boards were running within a telecommunication switch. It's a very nice problem and you are facing it in the proper way with a peer-to-peer distributed solution.
I didn't go through all code but it seems each node is discovering the neighbour nodes in the network and everyone is creating a tree.
In select, the first argument should not be FD_SETSIZE but the highest-numbered file descriptor in any of the three sets (in this case the read set), plus 1.
The infinite loop is calling receiveSession which is creating all sockets again and then it reads. If a frame with your specific layer-2 protocol arrives in the middle and there is no socket listening for it, it will be discarded. Maybe your problem could be here.
When you send Ethernet frames directly, the hardware will complete the frame to the minimum Ethernet size: 64 octets (so you might receive padding data up to 46 octets - Octets not Bytes)
Please read here:
http://en.wikipedia.org/wiki/Ethernet_frame
It is good you chose an EtherType ETH_P_CUSTOM higher than 1536 that is not already in use but maybe you want to use a much higher number in order to minimize possibilities of collision with other protocols.
Something important. Your testbed now is with VM's which are usually x86 architectures, 64 bits. When you run your software in real devices with different processors, that might not be the situation. This is very important because you might have different architectures with different endianship and different integer size. That will affect the integer numbers you send, especially in ether_header, and the size of your structures. You have to use the the macros ntohs, ntohl, htons, htonl to change between host and network endianship (session is uint64_t). You should send data in network endianship. This is not solving your very current problem but you might have this problem in the future.
I am trying to implement user space usb driver using libusb1.0.9. I have lpc2148 blueboard(ARM7) with me..This board is loaded with opensource USB stack/firmware by Mr. Bertrik Sikken. Now my user space driver is trying read write with board. I am getting garbage data.
I want to know about the flow of bulk tranfer.
For any transfer/transaction is there kernel device driver involved??
and do we need usb gadget device driver also??
I am not able to understand that where the data gets copied.
Important thing is that when I read/write interrupt gets generated and I can see correct data on LCD. Do I need to read/write USBRxData/USBTxData?
Please do the needfull.
I tried the below code for bulk transfer read and write..
int usb_read(struct libusb_device *dev,struct libusb_device_handle *hDevice)
{
char *data,*data1;
struct libusb_endpoint_descriptor *ep;
struct libusb_interface_descriptor *id;
int len=64,r,ret_alt,ret_clm,ret_rst,i;
struct libusb_device **list;
data = (char *)malloc(512); //allocation of buffers
data1 = (char *)malloc(512);
memset(data,'\0',512);
memset(data1,'\0',512);
if(hDevice==NULL)
{
printf("\nNO device found\n");
return 0;
}
int ret_open = libusb_open(dev,&hDevice);
if(ret_open!=0)
{
printf("Error in libusb_open\n");
libusb_free_device_list(list,1);
return -1;
}
char str_tx[512]="G"; //data to send to device
char str_rx[512]; //receive string
data = str_tx;
printf("data::%s\t,str::%s\n",data,str_tx);
//printf("%c\n",data);
ep = active_config(dev,hDevice);
printf("after ep\n");
//printf("alt_interface = %d\n",alt_interface);
ret_rst = libusb_reset_device(hDevice);
if(ret_rst < 0)
{
printf("Error in reset :: %d",ret_rst);
return -1;
}
printf("original data1 : %s\n",data1);
r = libusb_bulk_transfer(hDevice,0x08,str_tx,512,&len,0);
//write to device buffer from data
printf("Error number :: %d\n",r);
int le = ep->bEndpointAddress;
int ty = ep->bDescriptorType;
int y = ep->bmAttributes;
printf("y::%d\tatt:: %d\n",y,ep->bmAttributes);
if(r==-1)
printf("Error in io\n");
if(r==0)
{
printf("data returned :: %s\n",data);
printf("len= %d\n",len);
printf("Device Button Pressed!!!!\n");
}
else
{
printf("Error in bulk transfer\n");
return -1;
}
r = libusb_bulk_transfer(hDevice,0x82,data1,512,&len,0);
//read from device buffer to data1
//str_rx = data1;
//printf("End point address::%d\n",le);
//printf("End point desc.type::%d\n",ty);
if(r==-1)
printf("Error in io\n");
if(r==0)
{
printf("data1 returned::%s\n",data1); //received string in data1
printf("len= %d\n",len);
printf("Device Button Pressed!!!!\n");
}
else
{
printf("Error in bulk transfer\n");
return -1;
}
return 0;
}
Try the code given below and it should work on lpc2148.
I have tested this with a lpc2148 configured to receive an interrupt from USB after a write happens (from user-space) and RTC starts running.
Answering to your question whether it involves kernel driver in read/write or not, as far as I have studied, You have to detach the kernel driver and claim the interface using libusb APIs. Though I am not sure whether it can be done without detaching it or not.
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <string.h>
#include </usr/local/include/libusb-1.0/libusb.h>
#define BULK_EP_OUT 0x82
#define BULK_EP_IN 0x08
int interface_ref = 0;
int alt_interface,interface_number;
int print_configuration(struct libusb_device_handle *hDevice,struct libusb_config_descriptor *config)
{
char *data;
int index;
data = (char *)malloc(512);
memset(data,0,512);
index = config->iConfiguration;
libusb_get_string_descriptor_ascii(hDevice,index,data,512);
printf("\nInterface Descriptors: ");
printf("\n\tNumber of Interfaces : %d",config->bNumInterfaces);
printf("\n\tLength : %d",config->bLength);
printf("\n\tDesc_Type : %d",config->bDescriptorType);
printf("\n\tConfig_index : %d",config->iConfiguration);
printf("\n\tTotal length : %lu",config->wTotalLength);
printf("\n\tConfiguration Value : %d",config->bConfigurationValue);
printf("\n\tConfiguration Attributes : %d",config->bmAttributes);
printf("\n\tMaxPower(mA) : %d\n",config->MaxPower);
free(data);
data = NULL;
return 0;
}
struct libusb_endpoint_descriptor* active_config(struct libusb_device *dev,struct libusb_device_handle *handle)
{
struct libusb_device_handle *hDevice_req;
struct libusb_config_descriptor *config;
struct libusb_endpoint_descriptor *endpoint;
int altsetting_index,interface_index=0,ret_active;
int i,ret_print;
hDevice_req = handle;
ret_active = libusb_get_active_config_descriptor(dev,&config);
ret_print = print_configuration(hDevice_req,config);
for(interface_index=0;interface_index<config->bNumInterfaces;interface_index++)
{
const struct libusb_interface *iface = &config->interface[interface_index];
for(altsetting_index=0;altsetting_index<iface->num_altsetting;altsetting_index++)
{
const struct libusb_interface_descriptor *altsetting = &iface->altsetting[altsetting_index];
int endpoint_index;
for(endpoint_index=0;endpoint_index<altsetting->bNumEndpoints;endpoint_index++)
{
const struct libusb_endpoint_desriptor *ep = &altsetting->endpoint[endpoint_index];
endpoint = ep;
alt_interface = altsetting->bAlternateSetting;
interface_number = altsetting->bInterfaceNumber;
}
printf("\nEndPoint Descriptors: ");
printf("\n\tSize of EndPoint Descriptor : %d",endpoint->bLength);
printf("\n\tType of Descriptor : %d",endpoint->bDescriptorType);
printf("\n\tEndpoint Address : 0x0%x",endpoint->bEndpointAddress);
printf("\n\tMaximum Packet Size: %x",endpoint->wMaxPacketSize);
printf("\n\tAttributes applied to Endpoint: %d",endpoint->bmAttributes);
printf("\n\tInterval for Polling for data Tranfer : %d\n",endpoint->bInterval);
}
}
libusb_free_config_descriptor(NULL);
return endpoint;
}
int main(void)
{
int r = 1;
struct libusb_device **devs;
struct libusb_device_handle *handle = NULL, *hDevice_expected = NULL;
struct libusb_device *dev,*dev_expected;
struct libusb_device_descriptor desc;
struct libusb_endpoint_descriptor *epdesc;
struct libusb_interface_descriptor *intdesc;
ssize_t cnt;
int e = 0,config2;
int i = 0,index;
char str1[64], str2[64];
char found = 0;
// Init libusb
r = libusb_init(NULL);
if(r < 0)
{
printf("\nfailed to initialise libusb\n");
return 1;
}
else
printf("\nInit Successful!\n");
// Get a list os USB devices
cnt = libusb_get_device_list(NULL, &devs);
if (cnt < 0)
{
printf("\nThere are no USB devices on bus\n");
return -1;
}
printf("\nDevice Count : %d\n-------------------------------\n",cnt);
while ((dev = devs[i++]) != NULL)
{
r = libusb_get_device_descriptor(dev, &desc);
if (r < 0)
{
printf("failed to get device descriptor\n");
libusb_free_device_list(devs,1);
libusb_close(handle);
break;
}
e = libusb_open(dev,&handle);
if (e < 0)
{
printf("error opening device\n");
libusb_free_device_list(devs,1);
libusb_close(handle);
break;
}
printf("\nDevice Descriptors: ");
printf("\n\tVendor ID : %x",desc.idVendor);
printf("\n\tProduct ID : %x",desc.idProduct);
printf("\n\tSerial Number : %x",desc.iSerialNumber);
printf("\n\tSize of Device Descriptor : %d",desc.bLength);
printf("\n\tType of Descriptor : %d",desc.bDescriptorType);
printf("\n\tUSB Specification Release Number : %d",desc.bcdUSB);
printf("\n\tDevice Release Number : %d",desc.bcdDevice);
printf("\n\tDevice Class : %d",desc.bDeviceClass);
printf("\n\tDevice Sub-Class : %d",desc.bDeviceSubClass);
printf("\n\tDevice Protocol : %d",desc.bDeviceProtocol);
printf("\n\tMax. Packet Size : %d",desc.bMaxPacketSize0);
printf("\n\tNo. of Configuraions : %d\n",desc.bNumConfigurations);
e = libusb_get_string_descriptor_ascii(handle, desc.iManufacturer, (unsigned char*) str1, sizeof(str1));
if (e < 0)
{
libusb_free_device_list(devs,1);
libusb_close(handle);
break;
}
printf("\nManufactured : %s",str1);
e = libusb_get_string_descriptor_ascii(handle, desc.iProduct, (unsigned char*) str2, sizeof(str2));
if(e < 0)
{
libusb_free_device_list(devs,1);
libusb_close(handle);
break;
}
printf("\nProduct : %s",str2);
printf("\n----------------------------------------");
if(desc.idVendor == 0xffff && desc.idProduct == 0x4)
{
found = 1;
break;
}
}//end of while
if(found == 0)
{
printf("\nDevice NOT found\n");
libusb_free_device_list(devs,1);
libusb_close(handle);
return 1;
}
else
{
printf("\nDevice found");
dev_expected = dev;
hDevice_expected = handle;
}
e = libusb_get_configuration(handle,&config2);
if(e!=0)
{
printf("\n***Error in libusb_get_configuration\n");
libusb_free_device_list(devs,1);
libusb_close(handle);
return -1;
}
printf("\nConfigured value : %d",config2);
if(config2 != 1)
{
libusb_set_configuration(handle, 1);
if(e!=0)
{
printf("Error in libusb_set_configuration\n");
libusb_free_device_list(devs,1);
libusb_close(handle);
return -1;
}
else
printf("\nDevice is in configured state!");
}
libusb_free_device_list(devs, 1);
if(libusb_kernel_driver_active(handle, 0) == 1)
{
printf("\nKernel Driver Active");
if(libusb_detach_kernel_driver(handle, 0) == 0)
printf("\nKernel Driver Detached!");
else
{
printf("\nCouldn't detach kernel driver!\n");
libusb_free_device_list(devs,1);
libusb_close(handle);
return -1;
}
}
e = libusb_claim_interface(handle, 0);
if(e < 0)
{
printf("\nCannot Claim Interface");
libusb_free_device_list(devs,1);
libusb_close(handle);
return -1;
}
else
printf("\nClaimed Interface\n");
active_config(dev_expected,hDevice_expected);
// Communicate
char *my_string, *my_string1;
int transferred = 0;
int received = 0;
int length = 0;
my_string = (char *)malloc(nbytes + 1);
my_string1 = (char *)malloc(nbytes + 1);
memset(my_string,'\0',64);
memset(my_string1,'\0',64);
strcpy(my_string,"prasad divesd");
length = strlen(my_string);
printf("\nTo be sent : %s",my_string);
e = libusb_bulk_transfer(handle,BULK_EP_IN,my_string,length,&transferred,0);
if(e == 0 && transferred == length)
{
printf("\nWrite successful!");
printf("\nSent %d bytes with string: %s\n", transferred, my_string);
}
else
printf("\nError in write! e = %d and transferred = %d\n",e,transferred);
sleep(3);
i = 0;
for(i = 0; i < length; i++)
{
e = libusb_bulk_transfer(handle,BULK_EP_OUT,my_string1,64,&received,0); //64 : Max Packet Lenght
if(e == 0)
{
printf("\nReceived: ");
printf("%c",my_string1[i]); //will read a string from lcp2148
sleep(1);
}
else
{
printf("\nError in read! e = %d and received = %d\n",e,received);
return -1;
}
}
e = libusb_release_interface(handle, 0);
libusb_close(handle);
libusb_exit(NULL);
printf("\n");
return 0;
}
To handle kernal detaching.
if(libusb_kernel_driver_active(dev_handle, 0) == 1) //find out if kernel driver is attached
{
cout << "Kernel Driver Active" << endl;
if(libusb_detach_kernel_driver(dev_handle, 0) == 0) //detach it
{
cout << "Kernel Driver Detached!" << endl;
}
}