From 5c974d1f80d6bbbcbbe7138fec974a79379702b2 Mon Sep 17 00:00:00 2001
From: Franciszek Malinka <franciszek.malinka@gmail.com>
Date: Tue, 16 Mar 2021 19:31:22 +0100
Subject: pracownia 1 z sieci

---
 Semestr 4/sieci/pracownia1/icmp_receive.c | 53 +++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 Semestr 4/sieci/pracownia1/icmp_receive.c

(limited to 'Semestr 4/sieci/pracownia1/icmp_receive.c')

diff --git a/Semestr 4/sieci/pracownia1/icmp_receive.c b/Semestr 4/sieci/pracownia1/icmp_receive.c
new file mode 100644
index 0000000..07d3b69
--- /dev/null
+++ b/Semestr 4/sieci/pracownia1/icmp_receive.c	
@@ -0,0 +1,53 @@
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+
+void print_as_bytes (unsigned char* buff, ssize_t length)
+{
+	for (ssize_t i = 0; i < length; i++, buff++)
+		printf ("%.2x ", *buff);	
+}
+
+
+int main()
+{
+	int sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
+	if (sockfd < 0) {
+		fprintf(stderr, "socket error: %s\n", strerror(errno)); 
+		return EXIT_FAILURE;
+	}
+
+	for (;;) {
+		
+		struct sockaddr_in 	sender;	
+		socklen_t 			sender_len = sizeof(sender);
+		u_int8_t 			buffer[IP_MAXPACKET];
+
+		ssize_t packet_len = recvfrom (sockfd, buffer, IP_MAXPACKET, 0, (struct sockaddr*)&sender, &sender_len);
+		if (packet_len < 0) {
+			fprintf(stderr, "recvfrom error: %s\n", strerror(errno)); 
+			return EXIT_FAILURE;
+		}
+
+		char sender_ip_str[20]; 
+		inet_ntop(AF_INET, &(sender.sin_addr), sender_ip_str, sizeof(sender_ip_str));
+		printf ("Received IP packet with ICMP content from: %s\n", sender_ip_str);
+
+		struct ip* 			ip_header = (struct ip*) buffer;
+		ssize_t				ip_header_len = 4 * ip_header->ip_hl;
+
+		printf ("IP header: "); 
+		print_as_bytes (buffer, ip_header_len);
+		printf("\n");
+
+		printf ("IP data:   ");
+		print_as_bytes (buffer + ip_header_len, packet_len - ip_header_len);
+		printf("\n\n");
+	}
+
+	return EXIT_SUCCESS;
+}
-- 
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