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main.lc
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main.lc
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/* include main1 */
#include "udpcksum.h"## 1 ##src/udpcksum/main.c##
/* define global variables */## 2 ##src/udpcksum/main.c##
struct sockaddr *dest, *local;## 3 ##src/udpcksum/main.c##
struct sockaddr_in locallookup;## 4 ##src/udpcksum/main.c##
socklen_t destlen, locallen;## 5 ##src/udpcksum/main.c##
int datalink; /* from pcap_datalink(), in <net/bpf.h> */## 6 ##src/udpcksum/main.c##
char *device; /* pcap device */## 7 ##src/udpcksum/main.c##
pcap_t *pd; /* packet capture struct pointer */## 8 ##src/udpcksum/main.c##
int rawfd; /* raw socket to write on */## 9 ##src/udpcksum/main.c##
int snaplen = 200; /* amount of data to capture */## 10 ##src/udpcksum/main.c##
int verbose;## 11 ##src/udpcksum/main.c##
int zerosum; /* send UDP query with no checksum */## 12 ##src/udpcksum/main.c##
static void usage(const char *);## 13 ##src/udpcksum/main.c##
int## 14 ##src/udpcksum/main.c##
main(int argc, char *argv[])## 15 ##src/udpcksum/main.c##
{## 16 ##src/udpcksum/main.c##
int c, lopt = 0;## 17 ##src/udpcksum/main.c##
char *ptr, localname[1024], *localport;## 18 ##src/udpcksum/main.c##
struct addrinfo *aip;## 19 ##src/udpcksum/main.c##
if (argc < 2)## 20 ##src/udpcksum/main.c##
usage("");## 21 ##src/udpcksum/main.c##
/* end main1 */
/* include main2 */
opterr = 0; /* don't want getopt() writing to stderr */## 22 ##src/udpcksum/main.c##
while ((c = getopt(argc, argv, "0i:l:v")) != -1) {## 23 ##src/udpcksum/main.c##
switch (c) {## 24 ##src/udpcksum/main.c##
case '0':## 25 ##src/udpcksum/main.c##
zerosum = 1;## 26 ##src/udpcksum/main.c##
break;## 27 ##src/udpcksum/main.c##
case 'i':## 28 ##src/udpcksum/main.c##
device = optarg; /* pcap device */## 29 ##src/udpcksum/main.c##
break;## 30 ##src/udpcksum/main.c##
case 'l': /* local IP address and port#: a.b.c.d.p */## 31 ##src/udpcksum/main.c##
if ((ptr = strrchr(optarg, '.')) == NULL)## 32 ##src/udpcksum/main.c##
usage("invalid -l option");## 33 ##src/udpcksum/main.c##
*ptr++ = 0; /* null replaces final period */## 34 ##src/udpcksum/main.c##
localport = ptr; /* service name or port number */## 35 ##src/udpcksum/main.c##
strncpy(localname, optarg, sizeof(localname));## 36 ##src/udpcksum/main.c##
lopt = 1;## 37 ##src/udpcksum/main.c##
break;## 38 ##src/udpcksum/main.c##
case 'v':## 39 ##src/udpcksum/main.c##
verbose = 1;## 40 ##src/udpcksum/main.c##
break;## 41 ##src/udpcksum/main.c##
case '?':## 42 ##src/udpcksum/main.c##
usage("unrecognized option");## 43 ##src/udpcksum/main.c##
}## 44 ##src/udpcksum/main.c##
}## 45 ##src/udpcksum/main.c##
/* end main2 */
/* include main3 */
if (optind != argc - 2)## 46 ##src/udpcksum/main.c##
usage("missing <host> and/or <serv>");## 47 ##src/udpcksum/main.c##
/* 4convert destination name and service */## 48 ##src/udpcksum/main.c##
aip = Host_serv(argv[optind], argv[optind + 1], AF_INET, SOCK_DGRAM);## 49 ##src/udpcksum/main.c##
dest = aip->ai_addr; /* don't freeaddrinfo() */## 50 ##src/udpcksum/main.c##
destlen = aip->ai_addrlen;## 51 ##src/udpcksum/main.c##
/* ## 52 ##src/udpcksum/main.c##
* Need local IP address for source IP address for UDP datagrams.## 53 ##src/udpcksum/main.c##
* Can't specify 0 and let IP choose, as we need to know it for## 54 ##src/udpcksum/main.c##
* the pseudo-header to calculate the UDP checksum.## 55 ##src/udpcksum/main.c##
* If -l option supplied, then use those values; otherwise,## 56 ##src/udpcksum/main.c##
* connect a UDP socket to the destination to determine the right## 57 ##src/udpcksum/main.c##
* source address.## 58 ##src/udpcksum/main.c##
*/## 59 ##src/udpcksum/main.c##
if (lopt) {## 60 ##src/udpcksum/main.c##
/* 4convert local name and service */## 61 ##src/udpcksum/main.c##
aip = Host_serv(localname, localport, AF_INET, SOCK_DGRAM);## 62 ##src/udpcksum/main.c##
local = aip->ai_addr; /* don't freeaddrinfo() */## 63 ##src/udpcksum/main.c##
locallen = aip->ai_addrlen;## 64 ##src/udpcksum/main.c##
} else {## 65 ##src/udpcksum/main.c##
int s;## 66 ##src/udpcksum/main.c##
s = Socket(AF_INET, SOCK_DGRAM, 0);## 67 ##src/udpcksum/main.c##
Connect(s, dest, destlen);## 68 ##src/udpcksum/main.c##
/* the kernel chooses the correct local address for dest */## 69 ##src/udpcksum/main.c##
locallen = sizeof(locallookup);## 70 ##src/udpcksum/main.c##
local = (struct sockaddr *) &locallookup;## 71 ##src/udpcksum/main.c##
Getsockname(s, local, &locallen);## 72 ##src/udpcksum/main.c##
if (locallookup.sin_addr.s_addr == htonl(INADDR_ANY))## 73 ##src/udpcksum/main.c##
err_quit("Can't determine local address - use -l\n");## 74 ##src/udpcksum/main.c##
close(s);## 75 ##src/udpcksum/main.c##
}## 76 ##src/udpcksum/main.c##
open_output(); /* open output, either raw socket or libnet */## 77 ##src/udpcksum/main.c##
open_pcap(); /* open packet capture device */## 78 ##src/udpcksum/main.c##
setuid(getuid()); /* don't need superuser privileges any more */## 79 ##src/udpcksum/main.c##
Signal(SIGTERM, cleanup);## 80 ##src/udpcksum/main.c##
Signal(SIGINT, cleanup);## 81 ##src/udpcksum/main.c##
Signal(SIGHUP, cleanup);## 82 ##src/udpcksum/main.c##
test_udp();## 83 ##src/udpcksum/main.c##
cleanup(0);## 84 ##src/udpcksum/main.c##
}## 85 ##src/udpcksum/main.c##
/* end main3 */
static void## 86 ##src/udpcksum/main.c##
usage(const char *msg)## 87 ##src/udpcksum/main.c##
{## 88 ##src/udpcksum/main.c##
err_msg("usage: udpcksum [ options ] <host> <serv>\n"## 89 ##src/udpcksum/main.c##
"options: -0 send UDP datagram with checksum set to 0\n"## 90 ##src/udpcksum/main.c##
" -i s packet capture device\n"## 91 ##src/udpcksum/main.c##
" -l a.b.c.d.p local IP=a.b.c.d, local port=p\n"## 92 ##src/udpcksum/main.c##
" -v verbose output");## 93 ##src/udpcksum/main.c##
if (msg[0] != 0)## 94 ##src/udpcksum/main.c##
err_quit("%s", msg);## 95 ##src/udpcksum/main.c##
exit(1);## 96 ##src/udpcksum/main.c##
}## 97 ##src/udpcksum/main.c##