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#include <stdio.h>
#include <sys/socket.h>
#include <dlfcn.h>
#include <netinet/tcp.h>
#include <netinet/in.h>
#include <unistd.h>
#include <stdlib.h>
static int silent_mode = 0;
static unsigned send_delay = 0;
static unsigned send_chunk = 1;
char* xgetenv(const char* name, char* def){
char* rv = getenv(name);
return rv ? rv : def;
}
__attribute__((constructor)) void slowloris_init(){
silent_mode = strtoul(xgetenv("SLOWLORIS_SILENT", "0"), NULL, 10);
send_delay = strtoul(xgetenv("SLOWLORIS_DELAY", "0"), NULL, 10);
send_chunk = strtoul(xgetenv("SLOWLORIS_CHUNK", "1"), NULL, 10);
if(!silent_mode){
printf("preload-slowloris active\nDelay: %d\nChunking: %d\n", send_delay, send_chunk);
}
}
int socket(int domain, int type, int protocol){
static int (*real_socket) (int, int, int) = NULL;
if(!real_socket){
real_socket = dlsym(RTLD_NEXT, "socket");
}
int fd = real_socket(domain, type, protocol);
int enable = 1;
if(domain == AF_INET && type == SOCK_STREAM){
if(setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &enable, sizeof(enable)) < 0){
if(!silent_mode){
perror("setsockopt/tcp_nodelay");
}
}
}
return fd;
}
ssize_t send(int sockfd, const void* buf, size_t len, int flags){
static ssize_t (*real_send) (int, void*, size_t, int) = NULL;
if(!real_send){
real_send = dlsym(RTLD_NEXT, "send");
}
ssize_t rv = 0;
for(size_t u = 0; u < len; u += send_chunk){
ssize_t sent = real_send(sockfd, buf + u, (send_chunk < len - u) ? send_chunk : (len - u), flags);
if(sent < 0){
return -1;
}
rv += sent;
if(send_delay){
usleep(send_delay);
}
}
return rv;
}
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