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binder.cpp
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binder.cpp
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/*
this file will have all the binder code
add further comments
*/
#include "rpc.h"
#include "network.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <vector>
#include <exception>
#include <algorithm>
#define PORT "0" // port we're listening on, to be dynamically decided
// #define PORT "3600" // for some reason the dynamically allocated port was not accepting connections
static const size_t max_size= 256;
using namespace std;
int end1;
int sendTermMsg;
int breakWhile;
int numConnections;
struct serverFunction {
char* name;
int* argTypes;
int sockfd;
char* address;
int localfd;
int numArgs;
};
struct database {
vector<serverFunction> functions;
};
vector<serverFunction>::size_type db_idx;
//to follow code structure just follow the numbered comments
void sendMessage(int s, char* buf, unsigned int len);
int findNumber(vector<int>servers, int s) {
for (int i=0; i<servers.size(); i++) {
if (servers[i] == s) {
return 1;
}
}
return 0;
}
int main(int argc, char* argv[]) {
end1 = 0;
sendTermMsg = 0;
numConnections = 0;
breakWhile = 0;
// 1. Binder starts and creates a pool to connect to as many servers and clients it needs to
// Stores info about all of the servers
database db;
db_idx = -1;
fd_set master; // master file descriptor list
fd_set read_fds; // temp file descriptor list for select()
int fdmax; // maximum file descriptor number
int listener; // listening socket descriptor
int newfd; // newly accept()ed socket descriptor
struct sockaddr_storage remoteaddr; // remote address
socklen_t addrlen;
char* buf;
int nbytes;
char remoteIP[INET6_ADDRSTRLEN];
char hostIP[INET6_ADDRSTRLEN];
int i, rv;
struct addrinfo hints, *ai, *p;
FD_ZERO(&master); // clear the master and temp sets
FD_ZERO(&read_fds);
// get us a socket and bind it
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;
if ((rv = getaddrinfo(NULL, PORT, &hints, &ai)) != 0) {
// fprintf(stderr, "selectserver: %s\n", gai_strerror(rv));
exit(1);
}
int port_num;
for(p = ai; p != NULL; p = p->ai_next) {
listener = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
if (listener < 0) {
continue;
}
// lose the pesky "address already in use" error message
// setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
int ret = bind(listener, p->ai_addr, p->ai_addrlen);
getsockname(listener, (struct sockaddr *)p->ai_addr, (socklen_t *)&p->ai_addrlen);
port_num = getPort((struct sockaddr *)p->ai_addr);
if (ret < 0) {
close(listener);
continue;
}
break;
}
// if we got here, it means we didn't get bound
if (p == NULL) {
// fprintf(stderr, "selectserver: failed to bind\n");
exit(2);
}
// print your server name and port here
gethostname(hostIP, INET6_ADDRSTRLEN);
printf("BINDER_ADDRESS %s\n", hostIP);
printf("BINDER_PORT %d\n", htons(port_num));
freeaddrinfo(ai); // all done with this
// listen
if (listen(listener, 1000) == -1) {
// perror("listen");
exit(3);
}
// add the listener to the master set
FD_SET(listener, &master);
// keep track of the biggest file descriptor
fdmax = listener; // so far, it's this one
// main loop
for(;;) {
if (1 == sendTermMsg) {
sendTermMsg = 0;
vector<int> servers;
for (int i=0; i<db.functions.size(); i++) {
int s = db.functions[i].localfd;
if (findNumber(servers, s) == 1) {
} else {
servers.push_back(s);
}
}
// now we have a list of servers connected
for(int i = 0; i < servers.size(); i++) {
send_integer(servers[i], TERMINATE);
}
}
if (breakWhile) {
break;
}
read_fds = master; // copy it
if (select(fdmax+1, &read_fds, NULL, NULL, NULL) == -1) {
// perror("select");
exit(4);
}
// run through the existing connections looking for data to read
for(i = 0; i <= fdmax; i++) {
if (FD_ISSET(i, &read_fds)) { // we got one!!
if (i == listener) {
// handle new connections
addrlen = sizeof remoteaddr;
newfd = accept(listener,
(struct sockaddr *)&remoteaddr,
&addrlen);
if (newfd == -1) {
// perror("accept");
} else {
FD_SET(newfd, &master); // add to master set
if (newfd > fdmax) { // keep track of the max
fdmax = newfd;
}
numConnections++;
// 2. found a new connection, don't need to do anything here
// printf("selectserver: new connection from %s on "
// "socket %d\n",
// inet_ntop(remoteaddr.ss_family,
// get_in_addr((struct sockaddr*)&remoteaddr),
// remoteIP, INET6_ADDRSTRLEN),
// newfd);
}
} else {
// printf("handle data\n");
// 3. reading data sent by either server or client to decide what to do
int code;
int code_net;
// Get code
if ((nbytes = recv(i, &code_net, 4, 0)) <= 0) {
//got error or connection closed by client
if (nbytes == 0) {
//connection closed - if it was a server remove from database
// printf("selectserver: socket %d hung up\n", i);
for(std::vector<serverFunction>::size_type j = 0; j != db.functions.size();) {
if(db.functions[j].localfd == i){
db.functions.erase(db.functions.begin() + j);
} else {
j++;
}
}
} else {
// perror("recv");
}
close(i); // bye!
FD_CLR(i, &master); // remove from master set
numConnections--;
if ((end1 == 1) && (numConnections == 0)) {
breakWhile = 1;
}
break;
}
code = ntohl(code_net);
if (code == LOC_REQUEST){
char* name = recv_string(i);
int* argTypes = recv_argTypes(i);
int len = len_argTypes(argTypes);
// Determine which server info to return
serverFunction s;
bool found_server = false;
vector<serverFunction>::size_type copy_idx = db_idx;
vector<serverFunction>::size_type size = db.functions.size();
db_idx++;
for(; db_idx%size != copy_idx && size != 0; db_idx++) {
if (strcmp(db.functions[db_idx%size].name,name) == 0 && len == db.functions[db_idx%size].numArgs){
bool same = true;
for (int j=0;j<len; j++){
if (
get_arg_type(argTypes[j]) != get_arg_type(db.functions[db_idx%size].argTypes[j]) ||
is_input(argTypes[j]) != is_input(db.functions[db_idx%size].argTypes[j]) ||
is_output(argTypes[j]) != is_output(db.functions[db_idx%size].argTypes[j]) ||
(get_arg_length(argTypes[j]) > 0) != (get_arg_length(db.functions[db_idx%size].argTypes[j]) > 0)
){
same = false;
}
}
if (same){
s = db.functions.at(db_idx%size);
found_server = true;
break;
}
}
}
db_idx = db_idx%size;
if (!found_server){
if (strcmp(db.functions[copy_idx].name,name) == 0 && len == db.functions[copy_idx].numArgs){
bool same = true;
for (int j=0;j<len; j++){
if (
get_arg_type(argTypes[j]) != get_arg_type(db.functions[copy_idx].argTypes[j]) ||
is_input(argTypes[j]) != is_input(db.functions[copy_idx].argTypes[j]) ||
is_output(argTypes[j]) != is_output(db.functions[copy_idx].argTypes[j]) ||
(get_arg_length(argTypes[j]) > 0) != (get_arg_length(db.functions[copy_idx].argTypes[j]) > 0)
){
same = false;
}
}
if (same){
s = db.functions.at(copy_idx);
found_server = true;
// printf("found a server with a matching function\n");
}
}
}
if (!found_server){
send_integer(i, LOC_FAILURE);
} else {
send_integer(i, LOC_SUCCESS);
send_integer(i, s.sockfd);
send_string(i, s.address);
}
free(name);
} else if (code == REGISTER){
try {
char* server_identifier = recv_string(i);
int server_port = recv_integer(i);
char* name = recv_string(i);
int *argTypes = recv_argTypes(i);
int len = len_argTypes(argTypes);
// Register server info to database
serverFunction server_function = {name, argTypes, server_port, server_identifier, i, len};
db.functions.push_back(server_function);
// Stub code assuming we register successfully
send_integer(i, REGISTER_SUCCESS);
// This integer will hold any warnings or errors
int error = 0;
send_integer(i, error);
// Need to free these when server disconnects
//free(name);
//free(argTypes);
} catch (exception& e) {
send_integer(i, REGISTER_FAILURE);
// This integer will hold any warnings or errors
int error = -1;
send_integer(i, error);
}
} else if (code == TERMINATE) {
// loop through all servers and terminate
sendTermMsg = 1;
end1 = 1;
} else if (code == CACHE_REQUEST){
char* name = recv_string(i);
int* argTypes = recv_argTypes(i);
vector<serverFunction> matching_functions;
int len = len_argTypes(argTypes);
// find matching functions
for(std::vector<serverFunction>::size_type idx = 0; idx != db.functions.size(); idx++) {
if (strcmp(db.functions[idx].name,name) == 0 && len == db.functions[idx].numArgs){
bool same = true;
for (int j=0;j<len; j++){
if (
get_arg_type(argTypes[j]) != get_arg_type(db.functions[idx].argTypes[j]) ||
is_input(argTypes[j]) != is_input(db.functions[idx].argTypes[j]) ||
is_output(argTypes[j]) != is_output(db.functions[idx].argTypes[j]) ||
(get_arg_length(argTypes[j]) > 0) != (get_arg_length(db.functions[idx].argTypes[j]) > 0)
){
same = false;
}
}
if (same){
//printf ("%s %s\n", name, db.functions[idx].name);
matching_functions.push_back(db.functions[idx]);
}
}
}
//Send matching functions
// printf("size %d\n", matching_functions.size());
if (matching_functions.size() > 0){
send_integer(i, CACHE_SUCCESS);
send_integer(i, matching_functions.size());
for (std::vector<serverFunction>::size_type idx = 0; idx != matching_functions.size(); idx++){
// printf("sending server...%s\n", matching_functions[idx].name);
send_server(i, matching_functions[idx]);
}
} else {
send_integer(i, CACHE_FAILURE);
}
}
} // END handle data from client
} // END got new incoming connection
} // END looping through file descriptors
} // END for(;;)--and you thought it would never end!
return 0;
}
void sendMessage(int s, char* buf, unsigned int len) {
int total = 0; // how many bytes we've sent
int bytesleft = len; // how many we have left to send
int n;
while(total < len) {
n = send(s, buf+total, bytesleft, 0);
if (n == -1) { break; }
total += n;
bytesleft -= n;
}
len = total; // return number actually sent here
// if (n <0)
// perror("send");
}