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/*
* Network accounting
* capture-pcap.c - capture raw packets - pcap version
* (C) 1996 Ulrich Callmeier
*/
#include "netacct.h"
#include <pcap.h>
#include <sys/ethernet.h>
#include <netinet/ip_icmp.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <string.h>
void handle_ip(unsigned char buf[], char *devname, char *user);
pcap_t *pcap;
char errbuff[PCAP_ERRBUF_SIZE];
#define PCAP_SNAPLEN 128
#define PCAP_TMOUT 1000
void handle_frame (unsigned char[], int);
void init_capture()
{
struct promisc_device *p;
pcap = NULL;
p = cfg -> promisc;
if(p!=NULL)
{
pcap = pcap_open_live(p -> name, PCAP_SNAPLEN, 1, PCAP_TMOUT, errbuff);
if(pcap == NULL)
{
syslog(LOG_ERR, "can't pcap_open_live: %s\n", errbuff);
daemon_stop(0);
}
}
DEBUG(DBG_MISC, sprintf(dbg, "%s set to promiscous mode\n", p -> name));
}
void exit_capture(void)
{
if(pcap != NULL) pcap_close (pcap);
pcap = NULL;
}
inline int onnet(unsigned long int addr, struct ipnetwork *net)
{
return ((addr & net -> netmask) == net -> netnumber);
}
int onnetlist(unsigned long int addr, struct ipnetwork *netlist)
{
while(netlist!=NULL)
{
if(onnet(addr, netlist))
{
return 1;
}
netlist = netlist -> next;
}
return 0;
}
void do_packet(u_char *usr, const struct pcap_pkthdr *h, const u_char *p)
{
handle_frame(p, h->len);
}
void packet_loop()
{
int res;
while(running)
{
res = pcap_dispatch(pcap, -1, do_packet, NULL);
if(res == -1)
{
syslog(LOG_ERR, "pcap_dispatch: %s\n", pcap_geterr(pcap));
DEBUG(DBG_ERR, sprintf(dbg,"pcap_dispatch: %s\n", pcap_geterr(pcap)));
}
}
}
FILE *acct_file = stderr;
void
handle_frame (unsigned char buf[], int length)
{
static struct ip tmp_iphdr;
unsigned short srcport, dstport;
struct tcphdr tmp_tcphdr;
struct udphdr tmp_udphdr;
struct icmp tmp_icmphdr;
int found = 0;
struct mon_host_struct *ptr;
if(buf[12] * 256 + buf[13] == htons(ETHERTYPE_IP))
{
memcpy (&tmp_iphdr, &(buf[14]), sizeof (tmp_iphdr));
found = 0;
if(cfg->hostlist) { /* we specified at least one hostlimit tag */
/* if we don't monitor this IP, bail now - mk */
for(ptr=cfg->hostlist;ptr && !found;ptr=ptr->next) {
if(ptr->ipaddr == tmp_iphdr->saddr
|| ptr->ipaddr == tmp_iphdr->daddr)
found = 1;
}
if(!found) {
packets->ignored++;
continue;
}
}
if((tmp_iphdr.ip_src.s_addr & cfg->ignoremask) ==
(tmp_iphdr.ip_dst.s_addr & cfg->ignoremask))
{
packets->local++;
return;
}
else
{
if(onnetlist(tmp_iphdr.ip_src.s_addr,cfg->ignorenet) ||
onnetlist(tmp_iphdr.ip_dst.s_addr, cfg->ignorenet))
{
if(!(onnetlist(tmp_iphdr.ip_src.s_addr,cfg->dontignore) ||
onnetlist(tmp_iphdr.ip_dst.s_addr, cfg->dontignore)))
{
if(debug_level & DBG_IGNORE)
{
char tmp[18];
strcpy(tmp, intoa(tmp_iphdr.ip_src.s_addr));
DEBUG(DBG_IGNORE, sprintf(dbg, "netignored: %s -> %s\n",
tmp,intoa(tmp_iphdr.ip_dst.s_addr)));
}
packets->netignored++;
return;
}
}
packets->ip++;
switch(tmp_iphdr.ip_p)
{
case IPPROTO_UDP:
packets->ip_udp++;
memcpy (&tmp_udphdr, &buf[14 + tmp_iphdr.ip_hl * 4], sizeof (tmp_udphdr));
srcport = tmp_udphdr.uh_sport;
dstport = tmp_udphdr.uh_dport;
break;
case IPPROTO_TCP:
packets->ip_tcp++;
memcpy (&tmp_tcphdr, &buf[14 + tmp_iphdr.ip_hl * 4], sizeof (tmp_tcphdr));
srcport = tmp_tcphdr.th_sport;
dstport = tmp_tcphdr.th_dport;
break;
case IPPROTO_ICMP:
packets->ip_icmp++;
memcpy (&tmp_icmphdr, &buf[14 + tmp_iphdr.ip_hl * 4], sizeof (tmp_icmphdr));
srcport = tmp_icmphdr.icmp_type;
dstport = tmp_icmphdr.icmp_code;
break;
default:
packets->ip_other++;
srcport = dstport = 0;
break;
}
register_packet(tmp_iphdr.ip_src.s_addr,tmp_iphdr.ip_dst.s_addr,
tmp_iphdr.ip_p, srcport, dstport,
ntohs(tmp_iphdr.ip_len), strdup(cfg->promisc->name), NULL);
}
}
else
{
/* ETH_P_ARP, ETH_P_RARP, ETH_P_IPX, etc. */
packets -> ignored ++;
}
}
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