90 lines
2.4 KiB
C
90 lines
2.4 KiB
C
/*
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* ZMap Copyright 2013 Regents of the University of Michigan
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy
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* of the License at http://www.apache.org/licenses/LICENSE-2.0
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*/
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#include "packet.h"
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <netinet/ether.h>
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#include <netinet/ip.h>
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#include <netinet/tcp.h>
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#include <netinet/udp.h>
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#include <netinet/ip_icmp.h>
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#include <net/if.h>
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#include <arpa/inet.h>
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#include "state.h"
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void print_macaddr(struct ifreq* i)
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{
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printf("Device %s -> Ethernet %02x:%02x:%02x:%02x:%02x:%02x\n",
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i->ifr_name,
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(int) ((unsigned char *) &i->ifr_hwaddr.sa_data)[0],
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(int) ((unsigned char *) &i->ifr_hwaddr.sa_data)[1],
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(int) ((unsigned char *) &i->ifr_hwaddr.sa_data)[2],
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(int) ((unsigned char *) &i->ifr_hwaddr.sa_data)[3],
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(int) ((unsigned char *) &i->ifr_hwaddr.sa_data)[4],
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(int) ((unsigned char *) &i->ifr_hwaddr.sa_data)[5]);
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}
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void make_eth_header(struct ethhdr *ethh, macaddr_t *src, macaddr_t *dst)
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{
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memcpy(ethh->h_source, src, ETH_ALEN);
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memcpy(ethh->h_dest, dst, ETH_ALEN);
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ethh->h_proto = htons(ETH_P_IP);
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}
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void make_ip_header(struct iphdr *iph, uint8_t protocol, uint16_t len)
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{
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iph->ihl = 5; // Internet Header Length
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iph->version = 4; // IPv4
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iph->tos = 0; // Type of Service
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iph->tot_len = len;
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iph->id = htons(54321); // identification number
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iph->frag_off = 0; //fragmentation falg
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iph->ttl = MAXTTL; // time to live (TTL)
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iph->protocol = protocol; // upper layer protocol => TCP
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// we set the checksum = 0 for now because that's
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// what it needs to be when we run the IP checksum
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iph->check = 0;
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}
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void make_icmp_header(struct icmp *buf)
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{
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buf->icmp_type = ICMP_ECHO;
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buf->icmp_code = 0;
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buf->icmp_seq = 0;
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}
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void make_tcp_header(struct tcphdr *tcp_header, port_h_t dest_port)
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{
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tcp_header->seq = random();
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tcp_header->ack_seq = 0;
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tcp_header->res2 = 0;
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tcp_header->doff = 5; // data offset
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tcp_header->syn = 1;
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tcp_header->window = htons(65535); // largest possible window
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tcp_header->check = 0;
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tcp_header->urg_ptr = 0;
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tcp_header->dest = htons(dest_port);
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}
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void make_udp_header(struct udphdr *udp_header, port_h_t dest_port,
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uint16_t len)
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{
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udp_header->dest = htons(dest_port);
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udp_header->len = htons(len);
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// checksum ignored in IPv4 if 0
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udp_header->check = 0;
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}
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