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raw_socket.c
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102 lines (75 loc) · 2.34 KB
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#include "../include/raw_socket.h"
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/select.h>
int create_raw_socket(void) {
int sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
if(sockfd < 0) {
return -1;
}
struct timeval tv;
tv.tv_sec = 5;
tv.tv_usec = 0;
if(setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0) {
close(sockfd);
return -1;
}
return sockfd;
}
int send_icmp_packet(int sockfd, const struct icmp_packet* packet, const char* dest_ip) {
struct sockaddr_in dest_addr;
memset(&dest_addr, 0, sizeof(dest_addr));
dest_addr.sin_family = AF_INET;
if(inet_pton(AF_INET, dest_ip, &dest_addr.sin_addr) <= 0) {
return -1; // invalid ip address
}
// send packet
ssize_t sent = sendto(sockfd, packet, sizeof(struct icmp_packet), 0, (struct sockaddr*)&dest_addr, sizeof(dest_addr));
if(sent < 0) {
return -1;
}
return (int)sent;
}
int recv_icmp_packet(int sockfd, struct icmp_packet* packet, char* src_ip, int timeout_ms) {
fd_set read_fds;
FD_ZERO(&read_fds);
FD_SET(sockfd, &read_fds);
struct timeval timeout;
timeout.tv_sec = timeout_ms / 1000;
timeout.tv_usec = (timeout_ms % 1000) * 1000;
int ready = select(sockfd + 1, &read_fds, NULL, NULL, &timeout);
if(ready < 0) {
return -1;
} else if(ready == 0) {
return 0;
}
// Receive data
struct sockaddr_in src_addr;
socklen_t addr_len = sizeof(src_addr);
uint8_t buffer[1024];
ssize_t received = recvfrom(sockfd, buffer, sizeof(buffer), 0, (struct sockaddr*)&src_addr, &addr_len);
if(received < 0) {
return -1;
}
// Extract IP header size
int ip_header_len = (buffer[0] & 0x0F) * 4;
// Check if enough data
if(received < ip_header_len + (int)sizeof(struct icmp_packet)) {
return -1;
}
// Copy ICMP packet skipping the IP header and convert source IP to str
memcpy(packet, buffer + ip_header_len, sizeof(struct icmp_packet));
if(inet_ntop(AF_INET, &src_addr.sin_addr, src_ip, IP_ADDR_MAX_LEN) == NULL) {
return -1;
}
return (int)(received - ip_header_len);
}
void close_socket(int sockfd) {
if(sockfd >= 0) {
close(sockfd);
}
}