int main(void) {
int listenfd;
int fd, nbytes;
int inbuf;
int room;
char *after;
struct sockaddr_in client;
socklen_t socklen;
char buf[30];
listenfd = setup();
while (1) {
socklen = sizeof(client);
if ((fd = accept(listenfd, (struct sockaddr *)&peer, &socklen)) < 0) {
perror("accept");
} else {
printf("New connection on port %d\n",
ntohs(client.sin_port));
// Receive messages
inbuf = 0; // empty buffer
room = sizeof(buf); // whole buffer is room
after = buf;
while ((nbytes = read(fd, after, room)) > 0) {
inbuf = inbuf + nbytes;
int where = find_network_newline(buf, inbuf);
while (where >= 0) {
buf[where - 1] = '\n';
buf[where] = '\0';
printf ("Next message: %s", buf);
where++;
inbuf = inbuf - where;
memmove(buf, buf + where, inbuf);
// possibly the last read completed more than 1 line
where = find_network_newline(buf, inbuf);
}
room = sizeof(buf) - inbuf;
after = buf + inbuf;
}
close (fd);
}
}
}
/**
* Process 's' battle command where client p is attacking and wants to speak.
*/
int speak(struct client *p) {
char buf[256]; //buffer for client data (reading from client)
char outbuf[512]; //buffer for output to client
int nbytes;
int inbuf = 0; // buffer is empty; has no bytes
int room = sizeof(buf); // room == capacity of the whole buffer
char *after = buf; // start writing at beginning of buf
while (((nbytes = read(p->fd, after, room)) > 0)) {
inbuf += nbytes;
/* Check for buffer overflow */
if (inbuf >= sizeof(buf)) {
sprintf(outbuf, "\nServer cant handle this lengthy message..\r\n");
write(p->fd, outbuf, strlen(outbuf));
return -1;
}
int where = find_network_newline(buf, inbuf);
if (where >= 0) { // OK. we have a full line
buf[where] = '\0';
buf[where+1] = '\0';
printf("Next message: %s", buf);
sprintf(outbuf, "You speak:%s\r\n\n", buf);
write(p->fd, outbuf, strlen(outbuf));
/* Write the message to opponent */
sprintf(outbuf, "%s takes a break to tell you:\n%s\r\n\n", (p->partner)->name, buf);
write((p->partner)->fd, outbuf, strlen(outbuf));
inbuf -= (where+2);
int i;
for (i=0; i< where; i++) {
buf[i] = '\0';
}
memmove(buf,buf+where+2,inbuf);
break;
}
after = &buf[inbuf];
room = sizeof(buf) - inbuf;
}
if (nbytes == 0) { //Socket closed during speak
return -1; //To be removed by removeclient
}
return 0;
}
int main() {
int listenfd, clientfd, maxfd;
fd_set cset, rset;
Client *clients = NULL;
socklen_t clilen;
struct sockaddr_in cliaddr, servaddr;
int one = 1;
unsigned char temp_block_num, temp_block_inverse;
unsigned short temp_crc, block_crc;
char temp = 'C';
/*If a client disconnects while we are writing an ACK/NAK to them it sends
* a SIGPIPE which needs to be taken care of
*/
signal(SIGPIPE, SIG_IGN);
//Setup the main listening socket
listenfd = Socket(AF_INET, SOCK_STREAM, 0);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(PORT);
if ((setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(int)))
== -1) {
perror("setsockopt");
}
Bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr));
Listen(listenfd, 5);
FD_ZERO(&cset);
FD_SET(listenfd, &cset);
maxfd = listenfd;
while (1) {
/*
* Accept any clients that want to connect.
*/
rset = cset;
Select(maxfd + 1, &rset, NULL, NULL, 0);
// Check for new clients.
if (FD_ISSET(listenfd, &rset)) {
printf("New Client Connected\n");
Client *temp = Malloc(sizeof(Client));
clilen = sizeof(cliaddr);
clientfd = Accept(listenfd, (struct sockaddr *) &cliaddr, &clilen);
FD_SET(clientfd, &cset);
if (clientfd > maxfd) {
maxfd = clientfd;
}
// Populate the client struct with default starter data.
temp->fd = clientfd;
temp->inbuf = 0;
temp->state = initial;
temp->next = start;
temp->prev = NULL;
if (start) {
start->prev = temp;
}
start = temp;
continue;
}
/*
* Loop through all the clients in the linked list,
* checking their file descriptors for activity.
*/
clients = start;
while (clients) {
clientfd = clients->fd;
if (FD_ISSET(clientfd, &rset)) {
/*
* Using switch statement for states is too messy in terms of proper flow control
* so just using if statements instead; they're cleaner and easier to follow.
*/
if (clients->state == initial) {
// Read name of the file being sent.
clients->inbuf += Read(clientfd, &(clients->filename)[clients->inbuf], 20 - clients->inbuf);
if (find_network_newline(clients->filename, clients->inbuf) > 0) {
clients->filename[clients->inbuf - 2] = '\0';
// Open/create a file with the name.
clients->fp = open_file_in_dir(clients->filename, FILE_DIR);
// Assign defaults to client struct.
clients->state = pre_block;
clients->inbuf = 0;
clients->current_block = 1;
// Let the client know that the server is ready for the data.
temp = 'C';
Write(clientfd, &temp, 1);
}
}
if (clients->state == pre_block) {
// Find out what state the client is in.
Read(clientfd, (clients->buf), 1);
switch (clients->buf[0]) {
case EOT:
clients->state = finished;
break;
case SOH:
clients->state = get_block;
clients->blocksize = 132;
break;
case STX:
clients->state = get_block;
clients->blocksize = 1028;
break;
default:
temp = NAK;
Write(clientfd, &temp, 1);
}
}
if (clients->state == get_block) {
// Keep getting more of the payload till you have the required minimum amount.
clients->inbuf += Read(clientfd, (clients->buf) + (clients->inbuf), clients->blocksize - clients->inbuf);
if (clients->inbuf == clients->blocksize) {
clients->state = check_block;
}
}
if (clients->state == check_block) {
// Fetch block numbers from the packet.
temp_block_num = (clients->buf)[0];
temp_block_inverse = (clients->buf)[1];
// Make sure the block numbers are correct - drop the client if they're not.
if ((temp_block_num != (255 - temp_block_inverse) || (temp_block_num > clients->current_block))) {
FD_CLR(clientfd, &cset);
clients = drop_client(clients);
/*
* Since drop_client gives us the client after the one we dropped,
* we use continue to go back to start of the loop.
*/
break;
}
// Fetch and assemble the CRC given by client for the payload recieved.
temp_crc = 0;
temp_crc = (unsigned char)(clients->buf)[(clients->blocksize) - 2];
temp_crc <<= 8;
temp_crc |= (unsigned char)((clients->buf)[(clients->blocksize) - 1]);
// Calculate the actual CRC for the payload recieved.
block_crc = crc_message(XMODEM_KEY, (unsigned char *)((clients->buf) + 2), (clients->blocksize) - 4);
// Compare the given and calculated CRC to ensure payload integrity.
if ((temp_block_num == clients->current_block) && (temp_crc == block_crc)) {
printf("File: %s \t Block:%d Successfully recieved\n", clients->filename, clients->current_block);
// Write the payload to file if CRCs match
if (fwrite((clients->buf) + 2, 1, ((clients->blocksize) - 4), clients->fp) == 0) {
perror("Write to File error");
exit(-1);
}
// Send the client an ACK
temp = ACK;
Write(clientfd, &temp, 1);
// Increment service side block number counter and prepare for next block.
clients->state = pre_block;
clients->current_block += 1;
// Deal w/ wrap around when block number hits 255.
if (clients->current_block == 256) {
clients->current_block = 0;
}
// Reset the buffer position.
clients->inbuf = 0;
} else if (temp_crc != block_crc) {
printf("File: %s \t Block:%d CRC mismatch.\nExpected:%x, Got %x\n",
clients->filename, clients->current_block, temp_crc, block_crc);
// Sent the client a NAK if the CRCs didn't match and prepare for repeat block.
temp = NAK;
Write(clientfd, &temp, 1);
clients->state = pre_block;
clients->inbuf = 0;
} else if (temp_block_num < clients->current_block) {
// If we got a repeat block, just send the client an ACK.
temp = ACK;
Write(clientfd, &temp, 1);
}
}
if (clients->state == finished) {
printf("File Transfer Finished: %s\n", clients->filename);
// Cleanup after the client when transfer is finished.
// Send the client a final ACK.
temp = ACK;
Write(clientfd, &temp, 1);
// Remove the client and their socket from our list/set of clients.
FD_CLR(clientfd, &cset);
clients = drop_client(clients);
}
}
// Move on to the next client in the list (if any).
if (clients) {
clients = clients->next;
}
}
}
}
int handleclient(struct client *p, struct client *top) {
char outbuf[512];
struct client *oppo;
int len;
//New client, ask the name.
if (p->name == NULL) { //Ask the name
int inbuf = 0;
int where;
// buffer is empty; has no bytes
int room = sizeof(p->name_buf); // room == capacity of the whole buffer
char *after;
after = p->name_buf;
//Return number of bytes read
//nbytes = len
while (( len = read(p->fd, after, sizeof(p->name_buf) - 1)) > 0) {
inbuf += len;
where = find_network_newline(p->name_buf, inbuf);
if (where >= 0) { // OK. we have a full line
p->name_buf[where] = '\0';
p->name_buf[where+1] = '\0';
inbuf -= where + 2 ;
break;
}
room = sizeof(p->name_buf) - inbuf;
after = p->name_buf + inbuf;
}
p->name = p->name_buf;
//Tell the world someone joined.
sprintf(outbuf, "\r\n**%s joined the area.**\r\n", p->name);
broadcast(top, outbuf, strlen(outbuf));
sprintf(outbuf, "Welcome, %s! Awaiting opponent...\n", p->name);
write(p->fd, outbuf, strlen(outbuf));
}
//Start matching.
if(p->opponent == NULL) {
for (oppo = top; oppo != NULL; oppo = oppo->next) {
if(oppo != p) {
if(oppo->opponent == NULL && oppo->lastplayed != p) {
p->opponent = oppo;
p->hitpoints = rand() % 11 + 20;
p->powermoves = rand() % 3 + 1;
p->status = 1;//Attacking first
oppo->opponent = p;
oppo->hitpoints = rand() % 11 + 20;
oppo->powermoves = rand() % 3 + 1;
oppo->status = -1;//Defend first.
sprintf(outbuf, "You engage %s!\n", p->opponent->name);
write(p->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "You engage %s!\n", p->name);
write(p->opponent->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "\nReady for battle?(Please type 'y')\n");
write(p->fd, outbuf, strlen(outbuf));
}
}
}
return 0;
}
len = read(p->fd, p->buf, sizeof(p->buf) - 1);
//Handle battle.
if(p->opponent) {
if (p->status == 1) {
sprintf(outbuf, "Your hitpoints:%d\nYour powermoves: %d\n\n%s's hitpoints:%d\n\n",
p->hitpoints, p->powermoves, p->opponent->name, p->opponent->hitpoints);
write(p->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "Your hitpoints:%d\nYour powermoves: %d\n\n%s's hitpoints:%d\n\n",
p->opponent->hitpoints, p->opponent->powermoves, p->name, p->hitpoints);
write(p->opponent->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "(a)ttack\n(p)owermove\n(s)peak something\n");
write(p->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "Waiting for %s to strike...\n", p->name);
write(p->opponent->fd, outbuf, strlen(outbuf));
len = read(p->fd, p->buf, sizeof(p->buf) - 1);
p->status = -1;
p->opponent->status = 1;
} else if(p->status == -1) {
return 0;
}
if (len > 0) {
if(p->buf[0] == 'a') {
p->buf[0] = '\0';
int damage;
damage = rand() % 5 + 2;
p->opponent->hitpoints -= damage;
sprintf(outbuf, "\nYou hit %s for %d damage!\n", p->opponent->name, damage);
write(p->fd, outbuf, strlen(outbuf));//write outbuf to every client in top.
sprintf(outbuf, "\n%s hits you for %d damage!\n", p->name, damage);
write(p->opponent->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "\nReady for attacking/speaking?(Please say 'y')\n");
write(p->opponent->fd, outbuf, strlen(outbuf));
if(p->opponent->hitpoints <= 0) {
sprintf(outbuf, "\n%s gives up. You win!\n", p->opponent->name);
write(p->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "\nYou are no match for %s. You scurry away...\n", p->name);
write(p->opponent->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "Awaiting opponent...\n");
write(p->fd, outbuf, strlen(outbuf));
write(p->opponent->fd, outbuf, strlen(outbuf));
p->lastplayed = p->opponent;
p->opponent->lastplayed = p;
moveToEnd(top, p);
moveToEnd(top, p->opponent);
p->opponent->opponent = NULL;
p->opponent = NULL;
}
return 0;
} else if(p->buf[0] == 'p') {
p->buf[0] = '\0';
int possibility;
int damage;
possibility = rand() % 2 + 0;
p->powermoves -= 1;
if(possibility == 0) { //Miss it;
sprintf(outbuf, "\nYou missed %s!\n", p->opponent->name);
write(p->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "\n%s missed you!\n", p->name);
write(p->opponent->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "\nReady for attacking/speaking?(Please say 'y')\n");
write(p->opponent->fd, outbuf, strlen(outbuf));
return 0;
} else {
damage = 3 * (rand() % 5 + 2);
p->opponent->hitpoints -= damage;
sprintf(outbuf, "\nYou powermoves %s for %d damage!\n", p->opponent->name, damage);
write(p->fd, outbuf, strlen(outbuf));//write outbuf to every client in top.
sprintf(outbuf, "\n%s powermoves you for %d damage!\n", p->name, damage);
write(p->opponent->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "\nReady for attacking/speaking?(Please say 'y')\n");
write(p->opponent->fd, outbuf, strlen(outbuf));
if(p->opponent->hitpoints <= 0) {
sprintf(outbuf, "\n%s gives up. You win!\n", p->opponent->name);
write(p->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "\nYou are no match for %s. You scurry away...\n", p->name);
write(p->opponent->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "Awaiting opponent...\n");
write(p->fd, outbuf, strlen(outbuf));
write(p->opponent->fd, outbuf, strlen(outbuf));
p->lastplayed = p->opponent;
p->opponent->lastplayed = p;
moveToEnd(top, p);
moveToEnd(top, p->opponent);
p->opponent->opponent = NULL;
p->opponent = NULL;
}
return 0;
}
} else if(p->buf[0] == 's') {
p->buf[0] = '\0';
sprintf(outbuf, "Speak:");
write(p->fd, outbuf, strlen(outbuf));
int inbuf = 0;
int where;
int room = sizeof(p->buf);
char *after;
//char name_buf[256];
p->buf[0] = '\0';
after = p->buf;
while (( len = read(p->fd, after, sizeof(p->buf) - 1)) > 0) {
inbuf += len;
where = find_network_newline(p->buf, inbuf);
if (where >= 0) { // OK. we have a full line
p->buf[where] = '\0';
p->buf[where+1] = '\0';
inbuf -= where + 2 ;
break;
}
room = sizeof(p->buf) - inbuf;
after = p->buf + inbuf;
}
sprintf(outbuf, "You spoke:%s\n", p->buf);
write(p->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "%s spoke:%s\n", p->name, p->buf);
write(p->opponent->fd, outbuf, strlen(outbuf));
sprintf(outbuf, "\nReady for attacking/speaking?(Please say 'y')\n");
write(p->opponent->fd, outbuf, strlen(outbuf));
return 0;
}
} else if (len == 0) {//nothing in client p's fd
// socket is closed
printf("active\n");
sprintf(outbuf, "Awaiting opponent...\n");
write(p->opponent->fd, outbuf, strlen(outbuf));
p->opponent->opponent = NULL;
sprintf(outbuf, "--%s dropped. You win!\n", p->name);
write(p->opponent->fd, outbuf, strlen(outbuf));
printf("Disconnect from %s\n", inet_ntoa(p->ipaddr));
return -1;
} else { // shouldn't happen
perror("read");
return -1;
}
}
return -1;
}