"#include <gerbil.h>" <humbleat_private> writes: [roto router] Here's one I wrote a couple of years back for personal use. [This explains the permanent link I had with the Defence Signals Directorate for all those years btw ;)] /* fakeroute (c) 1996 Julian Assange <proffat_private> * All Rights Reserved * * config file ("hops" by default) contains tuples like thus: Dest IP Hop Fake router ms latency 203.4.184.222 0 204.70.10.250 5 203.4.184.222 1 204.70.10.250 10 203.4.184.222 2 198.32.136.88 15 203.4.184.222 3 137.209.200.202 20 203.4.184.222 4 137.209.60.1 25 203.4.184.222 5 198.26.127.26 30 203.4.184.222 -1 203.4.184.222 35 203.4.184.217 0 204.70.10.250 5 203.4.184.217 1 204.70.10.250 10 203.4.184.217 2 198.32.136.88 15 203.4.184.217 3 137.209.200.202 20 203.4.184.217 4 137.209.60.1 25 203.4.184.217 5 198.26.127.26 30 203.4.184.217 -1 203.4.184.222 35 */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <sys/types.h> #include <sys/types.h> #include <sys/time.h> #include <sys/socket.h> #include <netinet/in_systm.h> #include <netinet/in.h> #include <netinet/ip.h> #include <netinet/udp.h> #include <netinet/ip_icmp.h> #include <arpa/inet.h> #include <pcap.h> #define bool int #define TRUE 1 #define FALSE 0 #define ENDIAN_RAW_BUG 1 typedef u_short port_t; pcap_t *pd; struct bpf_program fcode; u_char *pcap_userdata; struct in_addr localnet, netmask; char ebuf[PCAP_ERRBUF_SIZE]; int raw; int a_max_ttl = 1; int a_timeout = 300; int a_verbose = 0; void ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p); void ppp_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p); void analyze_udp(struct ip *ip); struct hop { struct hop *next; struct in_addr dst, hop; int latency; /* delay */ int ttl; }; struct hop *hops; struct udp_state { struct udp_state *next; struct in_addr src, dst; port_t sport; time_t last_packet; }; struct udp_state *state; struct udp_state *queue; void pexit(char *err) { perror(err); exit(1); } void eexit(char *err) { fprintf(stderr, "fatal error: %s\n", err); exit(1); } void * xmalloc(int n) { void *p=malloc(n); if (!p) pexit("malloc"); return p; } u_short fast_icmp_cksum(struct icmp *icmp) /* well, for C anyway.. */ { register u_short *u = (u_short *)icmp; register int sum = 0; sum = *u++; u++; /* skip checksum */ sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u++; sum += *u; sum = (sum >> 16) + (sum & 0xffff); /* fold accumulated carries */ sum += sum>>16; return (u_short) ~sum; } struct printer { pcap_handler f; int type; }; /* XXX needed if using old bpf.h */ #ifndef DLT_ATM_RFC1483 #define DLT_ATM_RFC1483 11 #endif static struct printer printers[] = { { ether_if_print, DLT_EN10MB }, { ether_if_print, DLT_IEEE802 }, /* { sl_if_print, DLT_SLIP }, */ { ppp_if_print, DLT_PPP }, /* { fddi_if_print, DLT_FDDI }, { null_if_print, DLT_NULL }, { atm_if_print, DLT_ATM_RFC1483 }, */ { NULL, 0 }, }; static pcap_handler lookup_printer(int type) { struct printer *p; for (p = printers; p->f; ++p) if (type == p->type) return p->f; fprintf(stderr, "unknown data link type 0x%x", type); exit(1); /* NOTREACHED */ } void open_pcap(char *dev, bool f_promisc, char *filt, int usec) { if (!dev) { dev = pcap_lookupdev(ebuf); if (!dev) eexit(ebuf); } pd = pcap_open_live(dev, 96, f_promisc, usec, ebuf); if (!pd) eexit(ebuf); if (pcap_lookupnet(dev, &localnet.s_addr, &netmask.s_addr, ebuf) < 0) eexit(ebuf); if (pcap_compile(pd, &fcode, filt, 1, (u_long)netmask.s_addr) < 0) eexit(pcap_geterr(pd)); if (pcap_setfilter(pd, &fcode) < 0) eexit(pcap_geterr(pd)); } void ether_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p) { p += 14; analyze_udp((struct ip *)p); } void ppp_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p) { p += 4; analyze_udp((struct ip *)p); } struct hop * find_hop(struct in_addr dst, int ttl) { struct hop *p, *ret=NULL; for (p = hops; p; p=p->next) { if (p->dst.s_addr == dst.s_addr) { if (p->ttl == ttl) return p; if (p->ttl == -1) ret = p; } } return ret; } void icmp_reply(struct ip *iip, struct hop *hop) { char buf[sizeof(struct ip) + sizeof(struct icmp) + 8]; struct ip *ip =(struct ip *)buf; struct icmp *i =(struct icmp *)(buf+sizeof(struct ip)); static u_short ip_id; bool f_dest = (hop->ttl == -1); struct sockaddr_in in; int len = sizeof (struct ip) + sizeof (struct icmp) + 8; /* don't bother with the options */ memset(&in, 0, sizeof in); in.sin_family = AF_INET; ip->ip_hl = sizeof (struct ip) / 4; ip->ip_v = 4; ip->ip_tos = 0; ip->ip_len = ENDIAN_RAW_BUG? len: htons(len); ip->ip_id = htons(ip_id++); ip->ip_off = 0; ip->ip_ttl = 255; ip->ip_p = IPPROTO_ICMP; ip->ip_dst = in.sin_addr = iip->ip_src; ip->ip_src = hop->hop; ip->ip_sum = 0; /* let the os calculate it */ i->icmp_type = f_dest? ICMP_UNREACH: ICMP_TIMXCEED; i->icmp_code = f_dest? ICMP_UNREACH_PORT: ICMP_TIMXCEED_INTRANS; memcpy(&i->icmp_ip, iip, sizeof (struct ip)+8); i->icmp_cksum = fast_icmp_cksum(i); if (a_verbose>0) { printf("fakeroute: sending %s %s", f_dest? "ICMP_UNREACH_PORT": "ICMP_TIMXCEED", inet_ntoa(ip->ip_src)); printf(" -> %s for ttl %d\n", inet_ntoa(ip->ip_dst), iip->ip_ttl); } usleep(hop->latency); if (sendto (raw, ip, len, 0, (struct sockaddr *)&in, sizeof in)!=len) pexit("sendto"); } void analyze_udp(struct ip *ip) { struct udphdr *u; struct hop *hop; struct udp_state *p; static time_t lastclean; time_t t; u = (struct udphdr *)((char *)ip+ip->ip_hl*4); hop = find_hop(ip->ip_dst, ip->ip_ttl); if (!hop) return; for (p = state; p; p = p->next) { if (p->src.s_addr == ip->ip_src.s_addr && p->sport == u->uh_sport && p->dst.s_addr == ip->ip_dst.s_addr) goto found; } if (ip->ip_ttl > a_max_ttl) return; p = xmalloc(sizeof *p); p->next = state; p->src = ip->ip_src; p->dst = ip->ip_dst; p->sport = u->uh_sport; state = p; found: p->last_packet = t = time(NULL); icmp_reply(ip, hop); if (t > lastclean+10) { struct udp_state *prev = NULL; for (p=state; p;) { if (t > p->last_packet + a_timeout) { struct udp_state *p2 = p->next; if (prev) prev->next = p->next; else state = NULL; free (p); p = p2; } else { prev = p; p = p->next; } } } } void open_raw() { int yes = 1; raw = socket(AF_INET, SOCK_RAW, IPPROTO_RAW); if (raw<0) pexit("socket"); if (setsockopt(raw, IPPROTO_IP, IP_HDRINCL, (char *)&yes, sizeof(yes)) < 0) pexit("IP_HDRINCL"); } void populate_hops(char *fn) { FILE *fh; char host[32]; char hop[32]; struct hop *p; int latency; int ttl; int rules; fh = fopen(fn, "r"); if (!fh) pexit(fn); for (rules = 0; fscanf(fh, "%16s %d %16s %d%*[^\r\n]", host, &ttl, hop, &latency) == 4; rules++) { struct in_addr hostaddr, hopaddr; hostaddr.s_addr = inet_addr(host); if (hostaddr.s_addr == 0xffffffff) { fprintf(stderr, "bad address: %s\n", host); exit(1); } hopaddr.s_addr = inet_addr(hop); if (hopaddr.s_addr == 0xffffffff) { fprintf(stderr, "bad address: %s\n", hop); exit(1); } p = malloc(sizeof *p); p->dst = hostaddr; p->hop = hopaddr; p->ttl = ttl; p->latency = latency; p->next = hops; hops = p; } fprintf(stderr, "%d fakeroute rules loaded\n", rules); } void usage(char *av0) { exit(1); } int main(int argc, char **argv) { int c; pcap_handler printer; char *a_iface = NULL; char *a_filter = "udp"; char *a_hops = "hops"; int a_usec = 50; bool f_promisc = TRUE; while ((c=getopt(argc, argv, "i:ph:u:n:v"))!=-1) { switch(c) { case 'i': a_iface = optarg; break; case 'p': f_promisc = FALSE; break; case 'h': a_hops = optarg; break; case 'u': a_usec = atoi(optarg); break; case 't': a_max_ttl = atoi(optarg); break; case 'n': a_timeout = atoi(optarg); break; case 'v': a_verbose++; break; default: usage(argv[0]); /* NOT REACHED */ } } populate_hops(a_hops); open_pcap(a_iface, f_promisc, a_filter, a_usec); printer = lookup_printer(pcap_datalink(pd)); open_raw(); if (pcap_loop(pd, 0, printer, NULL) < 0) { fprintf(stderr, "%s: pcap_loop: %s\n", argv[0], pcap_geterr(pd)); exit(1); } pcap_close(pd); exit(0); }
This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 14:12:08 PDT