first draft

listen.c

@@ -0,0 +1,79 @@
+/* 
+ * $smu-mark$ 
+ * $name: listen.c$ 
+ * $author: Salvatore Sanfilippo <antirez@invece.org>$ 
+ * $copyright: Copyright (C) 1999 by Salvatore Sanfilippo$ 
+ * $license: This software is under GPL version 2 of license$ 
+ * $date: Fri Nov  5 11:55:48 MET 1999$ 
+ * $rev: 8$ 
+ */ 
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+#include "hping2.h" /* hping2.h includes hcmp.h */
+#include "globals.h"
+
+void listenmain(void)
+{
+	int size, ip_size;
+	int stdoutFD = fileno(stdout);
+	char packet[IP_MAX_SIZE+linkhdr_size];
+	char *p, *ip_packet;
+	struct myiphdr ip;
+	__u16 id;
+	static __u16 exp_id; /* expected id */
+
+	exp_id = 1;
+
+	while(1) {
+		size = read_packet(packet, IP_MAX_SIZE+linkhdr_size);
+		switch(size) {
+		case 0:
+			continue;
+		case -1:
+			exit(1);
+		}
+	
+		/* Skip truncated packets */
+		if (size < linkhdr_size+IPHDR_SIZE)
+			continue;
+		ip_packet = packet + linkhdr_size;
+
+		/* copy the ip header so it will be aligned */
+		memcpy(&ip, ip_packet, sizeof(ip));
+		id = ntohs(ip.id);
+		ip_size = ntohs(ip.tot_len);
+		if (size-linkhdr_size > ip_size)
+			size = ip_size;
+		else
+			size -= linkhdr_size;
+
+		if ((p = memstr(ip_packet, sign, size))) {
+			if (opt_verbose)
+				fprintf(stderr, "packet %d received\n", id);
+
+			if (opt_safe) {
+				if (id == exp_id)
+					exp_id++;
+				else {
+					if (opt_verbose)
+						fprintf(stderr, "packet not in sequence (id %d) received\n", id);
+					send_hcmp(HCMP_RESTART, exp_id);
+					if (opt_verbose)
+						fprintf(stderr, "HCMP restart from %d sent\n", exp_id);
+					continue; /* discard this packet */
+				}
+			}
+
+			p+=strlen(sign);
+			write(stdoutFD, p, size-(p-ip_packet));
+		}
+	}
+}