initial commit

.gitignore

@@ -0,0 +1 @@
+.vscode

ft_ping.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <inttypes.h>
+#include <stddef.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <errno.h>
+#include <netinet/in.h>
+#include <netinet/ip_icmp.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+struct t_socket
+{
+	struct sockaddr_in dst, src;
+	int fd;
+	int len;
+};

main.c

@@ -0,0 +1,87 @@
+#include "ft_ping.h"
+
+uint16_t calculate_checksum(uint16_t *data, int len)
+{
+	uint32_t checksum = 0;
+
+	while (len > 1)
+	{
+		checksum += *data++;
+		len -= 2;
+	}
+	if (len == 1)
+		checksum += *(uint8_t *)data;
+
+	while (checksum >> 16)
+		checksum = (checksum & 0xFFFF) + (checksum >> 16);
+	printf("checksum is : %X\n", (uint16_t)~checksum);
+	return (~checksum);
+}
+
+
+int ft_ping(struct t_socket sock, int *seq)
+{
+	unsigned char data[2048];
+	unsigned char data2[2048];
+	struct icmphdr *icmp_header = (struct icmphdr *)data;
+
+	memset(data, 0, sizeof(data));
+	memset(data2, 0, sizeof(data2));
+	sock.fd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
+	if (sock.fd < 0)
+	{
+		printf(strerror(errno));
+		fprintf(stderr, "ERROR : socket() failed\n");
+		return (0);
+	}
+	if (getsockname(sock.fd, (struct sockaddr *)&sock.src, &sock.len) < 0)
+	{
+		fprintf(stderr, "ERROR : getsockname() failed\n");
+		return (0);
+	}
+	sock.dst.sin_family = AF_INET;
+	memset(icmp_header, 0, sizeof(icmp_header));
+	icmp_header->type = ICMP_ECHO;
+	icmp_header->code = 0;
+	icmp_header->checksum = 0;
+	icmp_header->un.echo.id = getpid();
+	icmp_header->un.echo.sequence = *seq++;
+	icmp_header->checksum = calculate_checksum((uint16_t *)icmp_header, sizeof(icmp_header));
+	if (sendto(sock.fd, data, sizeof(data), 0, (struct sockaddr *)&sock.dst, sizeof(sock.dst)) == -1)
+	{
+		fprintf(stderr, "ERROR : sendto() failed\n");
+		return (0);
+	}
+	if (recvfrom(sock.fd, data2, sizeof(data2), 0, (struct sockaddr *)&sock.src, &sock.len) == -1)
+	{
+		fprintf(stderr, "ERROR : recvfrom() failed\n");
+		return (0);
+	}
+	struct icmphdr *icmp_recv_header = (struct icmphdr *)(data2 + 20);
+	if (icmp_recv_header->type != ICMP_ECHOREPLY || icmp_recv_header->code != 0)
+	{
+		fprintf(stderr, "ERROR : invalid packet received (code)\n");
+		return (0);
+	}
+	printf("success");
+	close(sock.fd);
+	return (1);
+}
+
+int main(int argc, char **argv)
+{
+	struct t_socket sock;
+	int seq = 1;
+	sock.src.sin_family = AF_INET;
+	if (argc != 2 || argv[1] == NULL || argv[1][0] == 0)
+	{
+		fprintf(stderr, "ERROR : usage : ping {-v?} [ADRESS]\n");
+		return (0);
+	}
+	if (gethostbyname(argv[1]) == NULL && inet_aton(argv[1], (struct in_addr *)&sock.dst.sin_addr.s_addr) == 0)
+	{
+		fprintf(stderr, "ERROR : %s is an invalid adress\n", argv[1]);
+		return (0);
+	}
+	return (ft_ping(sock, &seq));
+}