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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <time.h>
#include <unistd.h>
#define PORT 3233
void
ban(char* ban_list[], char* address, int* index, int *ban_size)
{
if (*index > 4) {
*index = 0;
}
if (*ban_size < 5) (*ban_size)++;
strcpy(ban_list[*index], address);
(*index)++;
}
int
is_banned_addr(char* ban_list[], int n, char* address)
{
int i;
for (i = 0; i < n; ++i) {
if (strcmp(ban_list[i], address) == 0)
return 1;
}
return 0;
}
int
main(int argc, char* argv[])
{
int sockfd, clientfd;
struct sockaddr_in addr;
socklen_t addrlen;
char buffer[12];
int nbytes;
char last_not_valid[15];
time_t now_time;
struct tm* now;
char* addr_str;
int i;
int ban_i;
int ban_size;
char* ban_list[5];
for (i = 0; i < 5; ++i) {
ban_list[i] = malloc(sizeof(char) * 15);
}
if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}
addr.sin_family = AF_INET;
addr.sin_port = htons(atoi(argv[1])); // TODO: change with PORT
addr.sin_addr.s_addr = INADDR_ANY;
addrlen = sizeof(addr);
if (bind(sockfd, (struct sockaddr*)&addr, addrlen) == -1) {
perror("bind");
exit(1);
}
if (listen(sockfd, 1) == -1) {
perror("listen");
exit(1);
}
ban_i = ban_size = 0;
while (1) {
if ((clientfd = accept(sockfd, (struct sockaddr*)&addr, &addrlen)) == -1) {
perror("accept");
continue;
}
if ((nbytes = read(clientfd, buffer, sizeof(buffer))) == -1) {
perror("read");
goto clientclear;
}
buffer[nbytes-1] = 0;
addr_str = inet_ntoa(addr.sin_addr);
if (is_banned_addr(ban_list, ban_size, addr_str)) {
sprintf(buffer, "BANNED\n");
} else if (strncmp(buffer, "TIME", 4) == 0) {
time(&now_time);
now = gmtime(&now_time);
sprintf(buffer, "%d:%d:%d UTC\n", now->tm_hour, now->tm_min, now->tm_sec);
memset(last_not_valid, 15, 0);
} else {
sprintf(buffer, "N/A\n");
if (strcmp(last_not_valid, addr_str) == 0) {
ban(ban_list, addr_str, &ban_i, &ban_size);
sprintf(buffer, "BANNED\n");
} else {
strcpy(last_not_valid, addr_str);
}
}
write(clientfd, buffer, strlen(buffer));
clientclear:
close(clientfd);
}
for (i = 0; i < 5; ++i) {
free(ban_list[i]);
}
close(sockfd);
return 0;
}
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