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/* IRPAS project - packet library
*
* FX <fx@phenoelit.de>
* Phenoelit (http://www.phenoelit.de)
* (c) 2k
*
* $Id: packets.c,v 1.2 2001/06/16 18:17:31 fx Exp $
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <time.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <protocols.h>
#include <packets.h>
packet_ifconfig_t packet_ifconfig;
/* pings the host, waits 'timeout' seconds and reports to stdout
* depending on the level of 'verbose'
*
* returns 0 on OK, -1 on error, 1 on timeout */
int icmp_ping(struct in_addr *t,int timeout,int verbose) {
#define RESP_ONE 1
#define RESP_MORE 2
int sfd;
struct sockaddr_in sin,fromaddr;
u_char *tpacket;
icmp_ping_t *pingh;
int psize;
u_int16_t pident;
int rc,addrsize,respond=0;
unsigned long start_t;
struct timespec sleeper = { 0, 10 };
if ((sfd=socket(AF_INET,SOCK_RAW,IPPROTO_ICMP))<0) {
perror("socket()");
return(-1);
}
rc=1;
if (setsockopt(sfd,SOL_SOCKET,SO_BROADCAST,(void *)&rc,sizeof(int))!=0) {
perror("setsockopt");
return (-1);
}
psize=sizeof(icmp_ping_t);
tpacket=(u_char *)smalloc(sizeof(icmp_ping_t)
+3 /* for my checksum function, which sometimes
steps over the mark */
);
pident=1+(u_int16_t) (65535.0*rand()/(RAND_MAX+1.0));
/* make up the icmp header */
pingh=(icmp_ping_t *)tpacket;
pingh->icmp.type=ICMP_ECHO;
pingh->icmp.code=0;
pingh->echo.identifier=htons(pident);
pingh->icmp.checksum=chksum((u_char *)pingh,psize);
memset(&sin,0,sizeof(struct sockaddr_in));
sin.sin_family=AF_INET;
sin.sin_port=htons(0);
memcpy(&(sin.sin_addr),t,sizeof(sin.sin_addr));
if (sendto(sfd,tpacket,psize,0,
(struct sockaddr *) &sin,
sizeof(struct sockaddr_in)) <0) {
perror("sendto()");
return(-1);
}
rc= O_NONBLOCK | fcntl(sfd, F_GETFL);
fcntl(sfd,F_SETFL,rc);
memset(&fromaddr,0,sizeof(struct sockaddr_in));
addrsize=sizeof(struct sockaddr_in);
start_t=(unsigned long)time(NULL);
memset(tpacket,0,psize);
while (start_t+timeout>=time(NULL)) {
if ((rc=recvfrom(sfd,(u_char *)tpacket,psize,0,
(struct sockaddr *)&fromaddr,
&addrsize))>=0) {
pingh=(icmp_ping_t *)(tpacket+sizeof(iphdr_t));
if (pingh->icmp.type==ICMP_ECHOREPLY) {
if ( /* address has to be the same */
(!memcmp(&(fromaddr.sin_addr),
&(sin.sin_addr),sizeof(sin.sin_addr)))
&&
(ntohs(pingh->echo.identifier)==pident)
){
/* normal response */
respond=RESP_ONE;
if (verbose>1)
printf("%s respond ... good\n",
inet_ntoa(fromaddr.sin_addr));
break;
} else if (
/** SECTION that handles bcast and network addrs **/
/* address is different - possibly bcast*/
(memcmp(&(fromaddr.sin_addr),
&(sin.sin_addr),sizeof(sin.sin_addr)))
&&
(ntohs(pingh->echo.identifier)==pident)
) {
if (verbose) {
fprintf(stderr,"%s respond instead of ",
inet_ntoa(fromaddr.sin_addr));
fprintf(stderr,"%s (broadcast or network address?)\n",
inet_ntoa(sin.sin_addr));
}
if (respond==0) respond=RESP_ONE; else respond=RESP_MORE;
}
/* it may be an ECHO REPLY, but it's not our's */
}
/* it's not an ECHO REPLY, therefore it is not OK */
}
nanosleep(&sleeper,NULL);
}
if (!respond) {
if (verbose) {
printf("%s not responding to ICMP Echo request\n",
inet_ntoa(*t));
}
free(tpacket);
close(sfd);
return 1;
} else if (respond==RESP_MORE) {
if (verbose) {
printf("%s is broadcast or network\n",
inet_ntoa(*t));
}
free(tpacket);
close(sfd);
return 1;
} else {
if (verbose) {
printf("%s is alive\n",
inet_ntoa(*t));
}
free(tpacket);
close(sfd);
return 0;
}
/* not reached */
return 0;
}
void makenonblock(int s) {
int rc=1;
rc= O_NONBLOCK | fcntl(s, F_GETFL);
fcntl(s,F_SETFL,rc);
}
int makebcast(int s) {
int rc=1;
if (setsockopt(s,SOL_SOCKET,SO_BROADCAST,(void *)&rc,sizeof(int))!=0) {
perror("setsockopt");
return (-1);
}
return(0);
}
/* opens the raw socket,
* RETURNS 0 on success or -1 on error */
int init_socket_eth(char *device) {
int sfd;
struct ifreq ifr;
if ((sfd=socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL)))<0) {
perror("socket()");
return (-1);
}
/* get HW addr */
memset(&ifr,0,sizeof(ifr));
strncpy(ifr.ifr_name, device, sizeof (ifr.ifr_name));
if (ioctl(sfd, SIOCGIFHWADDR, &ifr) < 0 ) {
perror("ioctl()");
return (-1);
}
memcpy(&(packet_ifconfig.eth),&ifr.ifr_hwaddr.sa_data,ETH_ALEN);
/* grab the IP address */
memset(&ifr,0,sizeof(ifr));
strncpy(ifr.ifr_name, device, sizeof (ifr.ifr_name));
if (ioctl(sfd, SIOCGIFADDR, &ifr) < 0 ) {
perror("ioctl()");
return (-1);
}
memcpy(&(packet_ifconfig.ip.s_addr),
&(*(struct sockaddr_in *)&ifr.ifr_addr).sin_addr.s_addr,
IP_ADDR_LEN);
/* get MTU for size */
memset(&ifr,0,sizeof(ifr));
strncpy(ifr.ifr_name, device, sizeof (ifr.ifr_name));
if (ioctl(sfd, SIOCGIFMTU, &ifr) < 0 ) {
perror("ioctl()");
return (-1);
}
packet_ifconfig.mtu=ifr.ifr_mtu;
/* get broadcast addr for size */
memset(&ifr,0,sizeof(ifr));
strncpy(ifr.ifr_name, device, sizeof (ifr.ifr_name));
if (ioctl(sfd, SIOCGIFBRDADDR, &ifr) < 0 ) {
perror("ioctl()");
return (-1);
}
memcpy(&(packet_ifconfig.bcast.s_addr),
&(*(struct sockaddr_in *)&ifr.ifr_addr).sin_addr.s_addr,
IP_ADDR_LEN);
return sfd;
}
/* creates the socket
* Returns the socket or -1 on error */
int init_socket_IP4(char *device, int broadcast) {
int sfd;
struct ifreq ifr;
int t=1;
if ((sfd=socket(AF_INET,SOCK_RAW,IPPROTO_RAW))<0) {
perror("socket()");
return(-1);
}
/* make a broadcast enabled socket if desired */
if (broadcast) {
if (setsockopt(
sfd,SOL_SOCKET,SO_BROADCAST,
(void *)&t,sizeof(int)) != 0) {
perror("setsockopt");
return (-1);
}
}
/* get HW addr */
memset(&ifr,0,sizeof(ifr));
strncpy(ifr.ifr_name, device, sizeof (ifr.ifr_name));
if (ioctl(sfd, SIOCGIFHWADDR, &ifr) < 0 ) {
perror("ioctl()");
return (-1);
}
memcpy(&(packet_ifconfig.eth),&ifr.ifr_hwaddr.sa_data,ETH_ALEN);
/* grab the IP address */
memset(&ifr,0,sizeof(ifr));
strncpy(ifr.ifr_name, device, sizeof (ifr.ifr_name));
if (ioctl(sfd, SIOCGIFADDR, &ifr) < 0 ) {
perror("ioctl()");
return (-1);
}
memcpy(&(packet_ifconfig.ip.s_addr),
&(*(struct sockaddr_in *)&ifr.ifr_addr).sin_addr.s_addr,
IP_ADDR_LEN);
/* get MTU for size */
memset(&ifr,0,sizeof(ifr));
strncpy(ifr.ifr_name, device, sizeof (ifr.ifr_name));
if (ioctl(sfd, SIOCGIFMTU, &ifr) < 0 ) {
perror("ioctl()");
return (-1);
}
packet_ifconfig.mtu=ifr.ifr_mtu;
/* get broadcast addr for size */
memset(&ifr,0,sizeof(ifr));
strncpy(ifr.ifr_name, device, sizeof (ifr.ifr_name));
if (ioctl(sfd, SIOCGIFBRDADDR, &ifr) < 0 ) {
perror("ioctl()");
return (-1);
}
memcpy(&(packet_ifconfig.bcast.s_addr),
&(*(struct sockaddr_in *)&ifr.ifr_addr).sin_addr.s_addr,
IP_ADDR_LEN);
return sfd;
}
/* sends out a raw IP packet
* returns 0 on success or -1 on error */
int sendpack_IP4(int sfd, u_char *packet,int plength) {
struct sockaddr_in sin;
iphdr_t *iph;
iph=(iphdr_t *)packet;
memset(&sin,0,sizeof(struct sockaddr_in));
sin.sin_family=AF_INET;
sin.sin_port=htons(0);
memcpy(&(sin.sin_addr),&(iph->daddr),sizeof(sin.sin_addr));
if (sendto(sfd,packet,plength,0,
(struct sockaddr *) &sin,
sizeof(struct sockaddr_in)) <=0) {
perror("sendto()");
return(-1);
}
return 0;
}
/* send's the ethernet frame,
* RETURNS the number of octets send or -1 on error */
int sendpack_eth(char *device, int atsock,
u_char *frame, int frame_length) {
struct sockaddr sa;
int sendBytes;
memset(&sa,0,sizeof(sa));
strncpy(sa.sa_data,device,sizeof(sa.sa_data));
sendBytes=sendto(atsock,frame,frame_length,0,&sa,sizeof(sa));
if (sendBytes<0) {
perror("send_ethernet_frame(): sendto");
return (-1);
} else if (sendBytes<frame_length) {
#ifdef __DEBUG__
fprintf(stderr,"send_ethernet_frame(): "
"WARNING: short send %d out off %d\n",sendBytes,frame_length);
#endif __DEBUG__
}
return sendBytes;
}
/* returns an initialized pointer to a memory area
* or hard-exits on failure */
void *smalloc(size_t size) {
void *p;
if ((p=malloc(size))==NULL) {
fprintf(stderr,"smalloc(): malloc failed\n");
exit (-2);
}
memset(p,0,size);
return p;
}
/* returns the checksum
* WARNING: if left over bytes are present, the memory after *data has to
* contain 0x00 series and should be part of the buffer
* -> make the buffer for data at least count+1 bytes long ! */
u_int16_t chksum(u_char *data, unsigned long count) {
u_int32_t sum = 0;
u_int16_t *wrd;
wrd=(u_int16_t *)data;
while( count > 1 ) {
sum = sum + *wrd;
wrd++;
count -= 2;
}
/* Add left-over byte, if any */
if( count > 0 ) {
#ifdef __DEBUG__
printf("Left over byte: %04X\n",((*wrd & 0xFF)<<8));
#endif /*__DEBUG__*/
sum = sum + ((*wrd &0xFF)<<8);
}
/* Fold 32-bit sum to 16 bits */
while (sum>>16) {
sum = (sum & 0xffff) + (sum >> 16);
}
return (~sum);
}
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