static int handler_tcp_tun_to_net(int fd, const struct worker_struct *ws,
char *buff, size_t len)
{
int dfd, keep = 1;
char *cbuff;
ssize_t rlen, err, clen;
struct ct_proto *hdr;
struct curve25519_proto *p;
socklen_t nlen;
size_t off = sizeof(struct ct_proto) + crypto_box_zerobytes;
if (!buff || len <= off)
return 0;
memset(buff, 0, len);
while ((rlen = read(fd, buff + off, len - off)) > 0) {
dfd = -1; p = NULL;
hdr = (struct ct_proto *) buff;
memset(hdr, 0, sizeof(*hdr));
hdr->flags = 0;
trie_addr_lookup(buff + off, rlen, ws->parent.ipv4, &dfd, NULL,
(size_t *) &nlen);
if (unlikely(dfd < 0)) {
memset(buff, 0, len);
continue;
}
err = get_user_by_socket(dfd, &p);
if (unlikely(err || !p)) {
memset(buff, 0, len);
continue;
}
clen = curve25519_encode(ws->c, p, (unsigned char *) (buff + off -
crypto_box_zerobytes), (rlen +
crypto_box_zerobytes), (unsigned char **)
&cbuff);
if (unlikely(clen <= 0)) {
memset(buff, 0, len);
continue;
}
hdr->payload = htons((uint16_t) clen);
set_tcp_cork(dfd);
write_exact(dfd, hdr, sizeof(struct ct_proto), 0);
write_exact(dfd, cbuff, clen, 0);
set_tcp_uncork(dfd);
memset(buff, 0, len);
}
return keep;
}
static int handler_tcp_net_to_tun(int fd, const struct worker_struct *ws,
char *buff, size_t len)
{
int keep = 1, count = 0;
char *cbuff;
ssize_t rlen, err, clen;
struct ct_proto *hdr;
struct curve25519_proto *p;
if (!buff || !len)
return 0;
while ((rlen = handler_tcp_read(fd, buff, len)) > 0) {
p = NULL;
hdr = (struct ct_proto *) buff;
if (unlikely(rlen < sizeof(struct ct_proto)))
goto close;
if (unlikely(rlen - sizeof(*hdr) != ntohs(hdr->payload)))
goto close;
if (unlikely(ntohs(hdr->payload) == 0))
goto close;
if (hdr->flags & PROTO_FLAG_EXIT) {
close:
remove_user_by_socket(fd);
trie_addr_remove(fd);
handler_tcp_notify_close(fd);
rlen = write(ws->parent.efd, &fd, sizeof(fd));
keep = 0;
return keep;
}
if (hdr->flags & PROTO_FLAG_INIT) {
syslog_maybe(auth_log, LOG_INFO, "Got initial userhash "
"from remote end!\n");
if (unlikely(rlen - sizeof(*hdr) <
sizeof(struct username_struct)))
goto close;
err = try_register_user_by_socket(ws->c,
buff + sizeof(struct ct_proto),
rlen - sizeof(struct ct_proto),
fd, auth_log);
if (unlikely(err))
goto close;
continue;
}
err = get_user_by_socket(fd, &p);
if (unlikely(err || !p))
continue;
clen = curve25519_decode(ws->c, p, (unsigned char *) buff +
sizeof(struct ct_proto),
rlen - sizeof(struct ct_proto),
(unsigned char **) &cbuff, NULL);
if (unlikely(clen <= 0))
continue;
cbuff += crypto_box_zerobytes;
clen -= crypto_box_zerobytes;
err = trie_addr_maybe_update(cbuff, clen, ws->parent.ipv4,
fd, NULL, 0);
if (unlikely(err))
continue;
err = write(ws->parent.tunfd, cbuff, clen);
count++;
if (count == 10) {
write_exact(ws->efd[1], &fd, sizeof(fd), 1);
/* Read later next data and let others process */
return keep;
}
}
return keep;
}
static int handler_tcp_tun_to_net(int fd, const struct worker_struct *ws,
char *buff, size_t len)
{
int dfd, state, keep = 1;
char *cbuff;
ssize_t rlen, err, clen;
struct ct_proto *hdr;
struct curve25519_proto *p;
socklen_t nlen;
size_t off = sizeof(struct ct_proto) + crypto_box_zerobytes;
if (!buff || len <= off) {
errno = EINVAL;
return 0;
}
errno = 0;
memset(buff, 0, len);
while ((rlen = read(fd, buff + off, len - off)) > 0) {
dfd = -1;
p = NULL;
hdr = (struct ct_proto *) buff;
memset(hdr, 0, sizeof(*hdr));
hdr->flags = 0;
trie_addr_lookup(buff + off, rlen, ws->parent.ipv4, &dfd, NULL,
(size_t *) &nlen);
if (unlikely(dfd < 0)) {
syslog(LOG_INFO, "CPU%u: TCP tunnel lookup failed: "
"unknown destination\n", ws->cpu);
memset(buff, 0, len);
continue;
}
err = get_user_by_socket(dfd, &p);
if (unlikely(err || !p)) {
syslog(LOG_ERR, "CPU%u: User protocol not in cache! "
"Dropping connection!\n", ws->cpu);
memset(buff, 0, len);
continue;
}
clen = curve25519_encode(ws->c, p, (unsigned char *) (buff + off -
crypto_box_zerobytes), (rlen +
crypto_box_zerobytes), (unsigned char **)
&cbuff);
if (unlikely(clen <= 0)) {
syslog(LOG_ERR, "CPU%u: TCP tunnel encrypt error: %zd\n",
ws->cpu, clen);
memset(buff, 0, len);
continue;
}
hdr->payload = htons((uint16_t) clen);
state = 1;
setsockopt(dfd, IPPROTO_TCP, TCP_CORK, &state, sizeof(state));
err = write_exact(dfd, hdr, sizeof(struct ct_proto), 0);
if (unlikely(err < 0))
syslog(LOG_ERR, "CPU%u: TCP tunnel write error: %s\n",
ws->cpu, strerror(errno));
err = write_exact(dfd, cbuff, clen, 0);
if (unlikely(err < 0))
syslog(LOG_ERR, "CPU%u: TCP tunnel write error: %s\n",
ws->cpu, strerror(errno));
state = 0;
setsockopt(dfd, IPPROTO_TCP, TCP_CORK, &state, sizeof(state));
errno = 0;
memset(buff, 0, len);
}
if (unlikely(rlen < 0 && errno != EAGAIN))
syslog(LOG_ERR, "CPU%u: TCP tunnel read error: %s\n",
ws->cpu, strerror(errno));
return keep;
}
static int handler_tcp_net_to_tun(int fd, const struct worker_struct *ws,
char *buff, size_t len)
{
int keep = 1, count = 0;
char *cbuff;
ssize_t rlen, err, clen;
struct ct_proto *hdr;
struct curve25519_proto *p;
if (!buff || !len) {
errno = EINVAL;
return 0;
}
errno = 0;
while ((rlen = handler_tcp_read(fd, buff, len)) > 0) {
p = NULL;
hdr = (struct ct_proto *) buff;
if (unlikely(rlen < sizeof(struct ct_proto)))
goto close;
if (unlikely(rlen - sizeof(*hdr) != ntohs(hdr->payload)))
goto close;
if (unlikely(ntohs(hdr->payload) == 0))
goto close;
if (hdr->flags & PROTO_FLAG_EXIT) {
close:
remove_user_by_socket(fd);
trie_addr_remove(fd);
handler_tcp_notify_close(fd);
rlen = write(ws->parent.efd, &fd, sizeof(fd));
if (rlen != sizeof(fd))
syslog(LOG_ERR, "CPU%u: TCP event write error: %s\n",
ws->cpu, strerror(errno));
keep = 0;
return keep;
}
if (hdr->flags & PROTO_FLAG_INIT) {
if (auth_log)
syslog(LOG_INFO, "Got initial userhash from remote end!\n");
if (unlikely(rlen - sizeof(*hdr) <
sizeof(struct username_struct)))
goto close;
err = try_register_user_by_socket(ws->c, buff + sizeof(struct ct_proto),
rlen - sizeof(struct ct_proto),
fd, auth_log);
if (unlikely(err))
goto close;
continue;
}
err = get_user_by_socket(fd, &p);
if (unlikely(err || !p)) {
syslog(LOG_ERR, "CPU%u: User protocol not in cache! "
"Dropping connection!\n", ws->cpu);
goto close;
}
clen = curve25519_decode(ws->c, p, (unsigned char *) buff +
sizeof(struct ct_proto),
rlen - sizeof(struct ct_proto),
(unsigned char **) &cbuff, NULL);
if (unlikely(clen <= 0)) {
syslog(LOG_ERR, "CPU%u: TCP net decryption error: %zd\n",
ws->cpu, clen);
goto close;
}
cbuff += crypto_box_zerobytes;
clen -= crypto_box_zerobytes;
err = trie_addr_maybe_update(cbuff, clen, ws->parent.ipv4,
fd, NULL, 0);
if (unlikely(err)) {
syslog(LOG_INFO, "CPU%u: Malicious packet dropped "
"from id %d\n", ws->cpu, fd);
continue;
}
err = write(ws->parent.tunfd, cbuff, clen);
if (unlikely(err < 0))
syslog(LOG_ERR, "CPU%u: TCP net write error: %s\n",
ws->cpu, strerror(errno));
count++;
if (count == 10) {
err = write_exact(ws->efd[1], &fd, sizeof(fd), 1);
if (unlikely(err != sizeof(fd)))
syslog(LOG_ERR, "CPU%u: TCP net put fd back in "
"pipe error: %s\n", ws->cpu, strerror(errno));
return keep;
}
errno = 0;
}
if (unlikely(rlen < 0 && errno != EAGAIN && errno != EBADF))
syslog(LOG_ERR, "CPU%u: TCP net read error: %s\n",
ws->cpu, strerror(errno));
return keep;
}
int main(int argc, char** argv)
{
if (argc != 2)
{
fprintf(stderr, "usage: RE216_SERVER port\n");
return 1;
}
// Initialization of the server address
struct sockaddr_in serv_addr;
int port = atoi(argv[1]);
serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);
serv_addr.sin_family=AF_INET;
serv_addr.sin_port=htons(port);
//Creation of the socket
int socket;
socket=do_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
// Binding
do_bind(socket,serv_addr,sizeof(serv_addr));
// Specify the socket to be a server socket and listen for at most 20 concurrent client
listen(socket,20);
// Initialization of the select() parameters
fd_set my_fd_set;
fd_set fd_temp;
FD_ZERO(&my_fd_set);
FD_SET(socket,&my_fd_set); // adding the server socket to my_fd_set
int max_fd = socket+1;
//Initialization of the user list storing user profiles created after the accept() function.
puser user_list = NULL;
char* name_by_default;
// Initialization of all the buffers and variables used in all the following options
int size_buffer = 300;
char* who_is_nick;
//Variable used in for loop for browsing through the user list
int k;
/* Infinite loop */
for (;;)
{
fd_temp=my_fd_set;
// select() is used to get the active sockets : Client or Server
int select_temp;
select_temp = select(max_fd,&fd_temp,NULL,NULL,NULL);
int i;
for(i=3;i<max_fd;i++) {
if(FD_ISSET(i, &fd_temp)) {
// New connections management
if(i==socket) {
// Accepting connections from the differents clients
int new_sock_client;
new_sock_client = do_accept(socket,serv_addr,sizeof(serv_addr));
printf("CLIENT %d IS NOW CONNECTED ON THE CHAT ! \n",new_sock_client-socket);
if (max_fd <= new_sock_client)
max_fd = new_sock_client +1;
FD_SET(new_sock_client,&my_fd_set); // Adding the new socket to my_fd_set
// Creating a new user profile
struct user new_user;
strcpy(new_user.name,"Client");
new_user.socket_client = new_sock_client;
new_user.next_user = user_list;
// Connection Data Management
char buffer[512];
char date_hour[40];
/* Date and hour management */
time_t timer_seconds = time(NULL);
struct tm * timeinfo = localtime(&timer_seconds);
// /whois <nickname> displaying management
strftime(date_hour, sizeof(date_hour), "%d/%m/%Y@%H:%M", timeinfo);
sprintf(buffer,"%s WITH IP ADDRESS 127.0.0.1 AND PORT %d \n",date_hour,port);
strcpy(new_user.connect_data,buffer);
// Add a new user to the user_list
user_list = add_user(user_list,new_user);
}
// Client management
else {
// Initialization of the buffer for incomming and outcomming information about any client
char buffer_client[size_buffer];
bzero(buffer_client,size_buffer);
// Get user information for the profile by the socket
puser user = get_user_by_socket(user_list,i);
// Read the sending message of the client
/*Receive the message from the socket by using recv */
int tempo_recvs=recv(i,buffer_client,size_buffer,0);
if (tempo_recvs != -1 && strncmp(buffer_client,"/quit\n",6) && strcmp(user->name,"Client") && strncmp(buffer_client,"/nick ",6) && strncmp(buffer_client,"/who\n",5) && strncmp(buffer_client,"/whois ",7)) {
printf("[%s]: %s",user->name, buffer_client);
} else if(tempo_recvs==-1){
printf("ERROR : AN ERROR OCCURED WHILE RECEIVING MESSAGE \n");
perror("recv"); exit(EXIT_FAILURE);
}
// /nick management
if(strncmp(buffer_client,"/nick ",6)==0) {
// Get the client input and remove the segmentation fault
name_by_default = strchr(buffer_client,' ') +sizeof(char);
strcpy(name_by_default+(strlen(name_by_default)-1)*sizeof(char),"\0");
int already_used=0;
// We browse through the user list in order to check if the nickname chosen by the Client is already used
for(k=4;k<max_fd;k++) {
if (k != i) {
puser nickuser = get_user_by_socket(user_list,k);
if(strcmp(nickuser->name,name_by_default)==0){
strcpy(buffer_client,"ERROR : NICKNAME ALREADY USED ! \n");
already_used=1;
break;
}
}
}
// If the nickname chosen by the Client isn't already used
if(already_used!=1 && strcmp(user->name,name_by_default)) {
// When a Client visit the chat for the first time
if (!strcmp(user->name,"Client")) {
strcpy(user->name,name_by_default);
sprintf(buffer_client,"WELCOME ON THE CHAT %s \n",user->name);
printf("[SERVER]: %s",buffer_client);
}
// If a Client is already connected on the chat with a nickname but he used /nick again, he can change his nickname
else {
printf("[SERVER]: %s IS NOW KNOWN AS %s \n",user->name,name_by_default);
strcpy(user->name,name_by_default);
sprintf(buffer_client,"YOUR NEW NICKNAME IS %s \n",user->name);
}
}
do_send_server(i, buffer_client, size_buffer);
}
// If a Client doesn't have a nickname yet, he can't talk on the chat
else if(strcmp(user->name,"Client")==0) {
strcpy(buffer_client,"ERROR : YOU MUST CHOOSE A NICKNAME BY USING /nick BEFORE CHATTING ! \n");
do_send_server(i, buffer_client, size_buffer);
}
// /who management
else if(strncmp(buffer_client,"/who\n",5)==0) {
strcpy(buffer_client,"MORE INFORMATION ABOUT ONLINE USERS -> THESE CLIENTS ARE CURRENTLY ONLINE :\n");
for(k=4;k<max_fd;k++){
puser whouser = get_user_by_socket(user_list,k);
if (strcmp(whouser->name,"Client")){
char who_name[60];
sprintf(who_name," %s \n",whouser->name);
strcat(buffer_client,who_name);
}
}
do_send_server(i, buffer_client, size_buffer);
}
// /whois management
else if(strncmp(buffer_client,"/whois ",7)==0) {
who_is_nick = strchr(buffer_client,' ') +sizeof(char);
strcpy(who_is_nick+(strlen(who_is_nick)-1)*sizeof(char),"\0");
puser whois_user;
whois_user = get_user_by_name(user_list,who_is_nick);
if (whois_user != NULL) {
sprintf(buffer_client,"MORE INFORMATION ABOUT CLIENT %s : HE IS CONNECTED SINCE %s \n", whois_user->name, whois_user->connect_data);
}
else{
strcpy(buffer_client,"ERROR : THERE IS NO ANY CLIENTS CONNECTED \n");
}
do_send_server(i, buffer_client, size_buffer);
}
// /quit management
else if(strncmp(buffer_client,"/quit\n",6)==0) {
close(i);
FD_CLR(i,&my_fd_set);
printf("[SERVER]: %s JUST LEFT THE CHAT -> THE CLIENT %d IS DISCONNECTED ! \n",user->name,user->socket_client-socket);
break;
}
//Sending back message to client
else {
strcpy(buffer_client,"\0");
do_send_server(i, buffer_client, size_buffer);
}
}
}
}
}
// Closing socket
close(socket);
return 0;
}
