inital public release

src/probe_modules/packet.h

@@ -0,0 +1,82 @@
+#include "state.h"
+
+#include <netinet/ether.h>
+#include <netinet/ip.h>
+#include <netinet/tcp.h>
+#include <netinet/ip_icmp.h>
+#include <netinet/udp.h>
+
+#ifndef HEADER_ZMAP_PACKET_H
+#define HEADER_ZMAP_PACKET_H
+
+#define MAX_PACKET_SIZE 4096
+
+typedef unsigned short __attribute__((__may_alias__)) alias_unsigned_short;
+
+void make_eth_header(struct ethhdr *ethh, macaddr_t *src, macaddr_t *dst);
+
+void make_ip_header(struct iphdr *iph, uint8_t, uint16_t);
+void make_tcp_header(struct tcphdr*, port_h_t);
+void make_icmp_header(struct icmp *);
+void make_udp_header(struct udphdr *udp_header, port_h_t dest_port,
+				uint16_t len);
+
+static inline unsigned short in_checksum(unsigned short *ip_pkt, int len)
+{
+	unsigned long sum = 0;
+	for (int nwords = len/2; nwords > 0; nwords--) {
+		sum += *ip_pkt++;
+	}
+	sum = (sum >> 16) + (sum & 0xffff);
+	sum += (sum >> 16);
+	return (unsigned short) (~sum);
+}
+
+__attribute__((unused)) static inline unsigned short ip_checksum(
+                unsigned short *buf)
+{
+	return in_checksum(buf, (int) sizeof(struct iphdr));
+}
+
+__attribute__((unused)) static inline unsigned short icmp_checksum(
+                unsigned short *buf)
+{
+	return in_checksum(buf, (int) sizeof(struct icmp));
+}
+
+static __attribute__((unused)) uint16_t tcp_checksum(unsigned short len_tcp,
+		uint32_t saddr, uint32_t daddr, struct tcphdr *tcp_pkt)
+{
+	alias_unsigned_short *src_addr = (alias_unsigned_short *) &saddr;
+	alias_unsigned_short *dest_addr = (alias_unsigned_short *) &daddr;
+
+	unsigned char prot_tcp = 6;
+	unsigned long sum = 0;
+	int nleft = len_tcp;
+	unsigned short *w;
+
+	w = (unsigned short *) tcp_pkt;
+	// calculate the checksum for the tcp header and tcp data
+	while(nleft > 1) {
+		sum += *w++;
+		nleft -= 2;
+	}
+	// if nleft is 1 there ist still on byte left.
+	// We add a padding byte (0xFF) to build a 16bit word
+	if (nleft > 0) {
+		sum += *w & ntohs(0xFF00);
+	}
+	// add the pseudo header
+	sum += src_addr[0];
+	sum += src_addr[1];
+	sum += dest_addr[0];
+	sum += dest_addr[1];
+	sum += htons(len_tcp);
+	sum += htons(prot_tcp);
+	sum = (sum >> 16) + (sum & 0xFFFF);
+	sum += (sum >> 16);
+	// Take the one's complement of sum
+	return (unsigned short) (~sum);
+}
+
+#endif