From 995a4acdf7d1d370d5e04d17131023e88671dd35 Mon Sep 17 00:00:00 2001
From: Namonay <thek7995@gmail.com>
Date: Sat, 14 Sep 2024 03:08:40 +0200
Subject: [PATCH] ditched libc icmphdr for a struct in ft_ping

---
 ft_ping.h |  9 +++++++++
 main.c    | 55 +++++++++++++++++++++++++++++++------------------------
 2 files changed, 40 insertions(+), 24 deletions(-)

diff --git a/ft_ping.h b/ft_ping.h
index 716663a..aaac178 100644
--- a/ft_ping.h
+++ b/ft_ping.h
@@ -15,6 +15,15 @@
 #include <arpa/inet.h>
 #include <netdb.h>
 
+struct icmp_header
+{
+	uint8_t type;
+	uint8_t code;
+	uint16_t checksum;
+	uint16_t id;
+	uint16_t seq;
+};
+
 struct t_socket
 {
 	struct sockaddr_in dst, src;
diff --git a/main.c b/main.c
index 491c204..744c5e7 100644
--- a/main.c
+++ b/main.c
@@ -19,78 +19,85 @@ uint16_t calculate_checksum(uint16_t *data, int len)
 }
 
 
-int ft_ping(struct t_socket sock, int *seq)
+int ft_ping(int sock, int *seq, struct sockaddr_in src, struct sockaddr_in dst)
 {
 	unsigned char data[2048];
 	unsigned char data2[2048];
-	struct icmphdr *icmp_header = (struct icmphdr *)data;
+	int len;
+	struct icmp_header *icmp_hdr = (struct icmp_header *)data;
 
 	memset(data, 0, sizeof(data));
 	memset(data2, 0, sizeof(data2));
-	sock.fd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
-	if (sock.fd < 0)
+	sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
+	if (sock < 0)
 	{
 		fprintf(stderr, "ERROR : socket() failed\n");
 		return (0);
 	}
-	if (getsockname(sock.fd, (struct sockaddr *)&sock.src, &sock.len) < 0)
+	if (getsockname(sock, (struct sockaddr *)&src, &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)
+	dst.sin_family = AF_INET;
+	memset(icmp_hdr, 0, sizeof(icmp_hdr));
+	icmp_hdr->type = ICMP_ECHO;
+	icmp_hdr->code = 0;
+	icmp_hdr->checksum = 0;
+	icmp_hdr->id = getpid();
+	icmp_hdr->seq = *seq++;
+	icmp_hdr->checksum = calculate_checksum((uint16_t *)icmp_hdr, sizeof(icmp_hdr));
+	if (sendto(sock, data, sizeof(data), 0, (struct sockaddr *)&dst, sizeof(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)
+	if (recvfrom(sock, data2, sizeof(data2), 0, (struct sockaddr *)&src, &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)
+	struct icmp_header *icmp_recv_hdr = (struct icmp_header *)(data2 + 20);
+	for (int i = 0; data[i]; i++)
+		printf("%c", data[i]);
+	for (int i = 0; data2[i]; i++)
+		printf("%c", data2[i]);
+	if (icmp_recv_hdr->type != ICMP_ECHOREPLY || icmp_recv_hdr->code != 0)
 	{
+		printf("%d %d\n", icmp_recv_hdr->type, icmp_recv_hdr->code);
 		fprintf(stderr, "ERROR : invalid packet received (code)\n");
 		return (0);
 	}
-	if (icmp_recv_header->un.echo.id != icmp_header->un.echo.id)
+	if (icmp_recv_hdr->id != icmp_hdr->id)
 	{
 		fprintf(stderr, "ERROR : invalid packet received (id is not matching)\n");
 		return (0);
 	}
-	if (icmp_recv_header->un.echo.sequence != icmp_header->un.echo.sequence)
+	if (icmp_recv_hdr->seq != icmp_hdr->seq)
 	{
 		fprintf(stderr, "ERROR : invalid packet received (sequence is not matching)\n");
 		return (0);
 	}
 	printf("success");
-	close(sock.fd);
+	close(sock);
 	return (1);
 }
 
 int main(int argc, char **argv)
 {
-	struct t_socket sock;
+	int sock;
+	struct sockaddr_in src, dst;
 	int seq = 1;
-	sock.src.sin_family = AF_INET;
+	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)
+	if (gethostbyname(argv[1]) == NULL && inet_aton(argv[1], (struct in_addr *)&dst.sin_addr.s_addr) == 0)
 	{
 		fprintf(stderr, "ERROR : %s is an invalid adress\n", argv[1]);
 		return (0);
 	}
-	return (ft_ping(sock, &seq));
+	return (ft_ping(sock, &seq, src, dst));
 }
\ No newline at end of file