-
Notifications
You must be signed in to change notification settings - Fork 0
/
server.c
214 lines (177 loc) · 5.61 KB
/
server.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#define MAX_CLIENTS 30
#define MAX_PENDING_CONNS 3
#define EXIT_SUCCESS 0
#define EXIT_FAILURE 1
#define TRUE 1
#define FALSE 0
#define GREETING_MSG "[Server] Welcome to BasicServer!\n"
#define MSG_LEN 1024
struct sockaddr_in address;
int addr_len;
int server_socket;
int client_socket;
int client_sockets[MAX_CLIENTS];
char* client_msg;
fd_set read_fds;
int server_port;// arg
//================================
void init_clients(void);
void init_server(void);
void accept_connections(void);
void handle_new_connections(void);
void handle_IO_operations(void);
//================================
int main(int argc, char* argv[])
{
if(argv[1] != NULL)
{
server_port = strtol(argv[1], NULL, 10);
if(server_port == 0)
{
printf("[ERROR] Missing arg: server PORT\n");
exit(EXIT_FAILURE);
}
}
else
{
printf("[ERROR] Missing arg: server PORT\n");
exit(EXIT_FAILURE);
}
init_server();
init_clients();
accept_connections();
}
void init_clients(void)
{
client_msg = (char*)malloc(MSG_LEN * sizeof(char*));
for(int i=0; i<MAX_CLIENTS; i++)
client_sockets[i] = 0;
}
void init_server(void)
{
// Create server socket
server_socket = socket(AF_INET, SOCK_STREAM, 0);// TCP/IPv4
if(server_socket == 0)
{
perror("[Server] Socket");
exit(EXIT_FAILURE);
}
// Set server socket type
address.sin_family = AF_INET;// IPv4
address.sin_addr.s_addr = INADDR_ANY;// all IPs of the machine
address.sin_port = htons(server_port);
addr_len = sizeof(address);
// Bind server socket to specified port
if(bind(server_socket, (struct sockaddr*)&address, sizeof(address)) < 0)
{
perror("[Server] Bind");
exit(EXIT_FAILURE);
}
// Try to specify max pending connections for server
if(listen(server_socket, MAX_PENDING_CONNS) < 0)// MAX_PENDING_CONNS for kernel TCP stack
{
perror("[Server] Listen");
exit(EXIT_FAILURE);
}
printf("[Server] Server is ready to use!\n");
printf("[Server] Connect to any of the machine IPs, using port: %d\n", server_port);
}
void accept_connections(void)
{
printf("[Server] Waiting for connections...\n\n");
while(TRUE)
{
// Clear socket set
FD_ZERO(&read_fds);
// Let server socket to be watched for an activity
FD_SET(server_socket, &read_fds);
int highest_socket = server_socket;// for select() optimization
// Let all child sockets to be watched by select()
for(int i=0; i<MAX_CLIENTS; i++)
{
client_socket = client_sockets[i];
if(client_socket > 0)
FD_SET(client_socket, &read_fds);
if(client_socket > highest_socket)
highest_socket = client_socket;
}
// Wait for an activity on one of the client sockets
// select(optimization, read fds, write fds, err fds, timeout struct(secs, microsecs))
if(select(highest_socket + 1, &read_fds, NULL, NULL, NULL) < 0)
{
perror("[Server] Select");
exit(EXIT_FAILURE);
}
handle_new_connections();
handle_IO_operations();
}
}
void handle_new_connections(void)
{
// Server socket is triggered - new connection incoming
if(FD_ISSET(server_socket, &read_fds))
{
int new_client_socket = accept(server_socket, (struct sockaddr*)&address, (socklen_t*)&addr_len);
if(new_client_socket < 0)
{
perror("[Server] Accept");
exit(EXIT_FAILURE);
}
printf("[Server] New connection! IP: %s:%d\n\n", inet_ntoa(address.sin_addr), ntohs(address.sin_port));
// Send greeting message
if(send(new_client_socket, GREETING_MSG, strlen(GREETING_MSG), 0) != strlen(GREETING_MSG))
{
perror("[Server] Send");
exit(EXIT_FAILURE);
}
// Add new socket to socket array
for(int i=0; i<MAX_CLIENTS; i++)
{
// Empty?
if(client_sockets[i] == 0)
{
client_sockets[i] = new_client_socket;
break;
}
}
}
}
void handle_IO_operations(void)
{
for(int i=0; i<MAX_CLIENTS; i++)
{
client_socket = client_sockets[i];
// Client socket is triggered, some I/O operation
if(FD_ISSET(client_socket, &read_fds))
{
memset(client_msg, 0, MSG_LEN * sizeof(char*));
if(recv(client_socket, client_msg, MSG_LEN * sizeof(char*), 0) == 0)
{
getpeername(client_socket, (struct sockaddr*)&address, (socklen_t*)&addr_len);
printf("[Server] Client disconnected, IP: %s:%d\n\n", inet_ntoa(address.sin_addr), ntohs(address.sin_port));
shutdown(client_socket, SHUT_RDWR);
close(client_socket);
client_sockets[i] = 0;
}
else
{
getpeername(client_socket, (struct sockaddr*)&address, (socklen_t*)&addr_len);
printf("[Server] Message from client IP: %s:%d\n", inet_ntoa(address.sin_addr), ntohs(address.sin_port));
printf("[Client] %s\n", client_msg);
char* message_back = "[Server] Message delivered\n";
send(client_socket, message_back, strlen(message_back), 0);
}
}
}
}