nexmon – Rev 1
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/*
* Stanford Enetfilter subroutines for tcpdump
*
* Based on the MERIT NNstat etherifrt.c and the Ultrix pcap-pf.c
* subroutines.
*
* Rayan Zachariassen, CA*Net
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/types.h>
#include <sys/time.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>
#include <pcap/bpf.h>
#include <net/enet.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <stdio.h>
#include <errno.h>
#include "interface.h"
struct packet_header {
#ifdef IBMRTPC
struct LengthWords length;
struct tap_header tap;
#endif /* IBMRTPC */
u_char packet[8]
};
extern int errno;
#define BUFSPACE (4*1024)
/* Forwards */
static void efReadError(int, char *);
void
readloop(int cnt, int if_fd, struct bpf_program *fp, printfunc printit)
{
#ifdef IBMRTPC
register struct packet_header *ph;
register u_char *bp;
register int inc;
#else /* !IBMRTPC */
static struct timeval tv = { 0 };
#endif /* IBMRTPC */
register int cc, caplen;
register struct bpf_insn *fcode = fp->bf_insns;
union {
struct packet_header hdr;
u_char p[BUFSPACE];
u_short s;
} buf;
while (1) {
if ((cc = read(if_fd, (char *)buf.p, sizeof(buf))) < 0)
efReadError(if_fd, "reader");
#ifdef IBMRTPC
/*
* Loop through each packet.
*/
bp = buf.p;
while (cc > 0) {
ph = (struct packet_header *)bp;
caplen = ph->tap.th_wirelen > snaplen ? snaplen : ph->tap
.th_wirelen ;
if (bpf_filter(fcode, (char *)ph->packet,
ph->tap.th_wirelen, caplen)) {
if (cnt >= 0 && --cnt < 0)
goto out;
(*printit)((char *)ph->packet,
(struct timeval *)ph->tap.th_timestamp,
ph->tap.th_wirelen, caplen);
}
inc = ph->length.PacketOffset;
cc -= inc;
bp += inc;
}
#else /* !IBMRTPC */
caplen = cc > snaplen ? snaplen : cc ;
if (bpf_filter(fcode, buf.hdr.packet, cc, caplen)) {
if (cnt >= 0 && --cnt < 0)
goto out;
(*printit)(buf.hdr.packet, &tv, cc, caplen);
}
#endif /* IBMRTPC */
}
out:
wrapup(if_fd);
}
/* Call ONLY if read() has returned an error on packet filter */
static void
efReadError(int fid, char *msg)
{
if (errno == EINVAL) { /* read MAXINT bytes already! */
if (lseek(fid, 0, 0) < 0) {
perror("tcpdump: efReadError/lseek");
exit(-1);
}
else
return;
}
else {
(void) fprintf(stderr, "tcpdump: ");
perror(msg);
exit(-1);
}
}
void
wrapup(int fd)
{
#ifdef IBMRTPC
struct enstats es;
if (ioctl(fd, EIOSTATS, &es) == -1) {
perror("tcpdump: enet ioctl EIOSTATS error");
exit(-1);
}
fprintf(stderr, "%d packets queued", es.enStat_Rcnt);
if (es.enStat_Rdrops > 0)
fprintf(stderr, ", %d dropped", es.enStat_Rdrops);
if (es.enStat_Reads > 0)
fprintf(stderr, ", %d tcpdump %s", es.enStat_Reads,
es.enStat_Reads > 1 ? "reads" : "read");
if (es.enStat_MaxRead > 1)
fprintf(stderr, ", %d packets in largest read",
es.enStat_MaxRead);
putc('\n', stderr);
#endif /* IBMRTPC */
close(fd);
}
int
initdevice(char *device, int pflag, int *linktype)
{
struct eniocb ctl;
struct enfilter filter;
u_int maxwaiting;
int if_fd;
#ifdef IBMRTPC
GETENETDEVICE(0, O_RDONLY, &if_fd);
#else /* !IBMRTPC */
if_fd = open("/dev/enet", O_RDONLY, 0);
#endif /* IBMRTPC */
if (if_fd == -1) {
perror("tcpdump: enet open error");
error(
"your system may not be properly configured; see \"man enet(4)\"");
exit(-1);
}
/* Get operating parameters. */
if (ioctl(if_fd, EIOCGETP, (char *)&ctl) == -1) {
perror("tcpdump: enet ioctl EIOCGETP error");
exit(-1);
}
/* Set operating parameters. */
#ifdef IBMRTPC
ctl.en_rtout = 1 * ctl.en_hz;
ctl.en_tr_etherhead = 1;
ctl.en_tap_network = 1;
ctl.en_multi_packet = 1;
ctl.en_maxlen = BUFSPACE;
#else /* !IBMRTPC */
ctl.en_rtout = 64; /* randomly picked value for HZ */
#endif /* IBMRTPC */
if (ioctl(if_fd, EIOCSETP, &ctl) == -1) {
perror("tcpdump: enet ioctl EIOCSETP error");
exit(-1);
}
/* Flush the receive queue, since we've changed
the operating parameters and we otherwise might
receive data without headers. */
if (ioctl(if_fd, EIOCFLUSH) == -1) {
perror("tcpdump: enet ioctl EIOCFLUSH error");
exit(-1);
}
/* Set the receive queue depth to its maximum. */
maxwaiting = ctl.en_maxwaiting;
if (ioctl(if_fd, EIOCSETW, &maxwaiting) == -1) {
perror("tcpdump: enet ioctl EIOCSETW error");
exit(-1);
}
#ifdef IBMRTPC
/* Clear statistics. */
if (ioctl(if_fd, EIOCLRSTAT, 0) == -1) {
perror("tcpdump: enet ioctl EIOCLRSTAT error");
exit(-1);
}
#endif /* IBMRTPC */
/* Set the filter (accept all packets). */
filter.enf_Priority = 3;
filter.enf_FilterLen = 0;
if (ioctl(if_fd, EIOCSETF, &filter) == -1) {
perror("tcpdump: enet ioctl EIOCSETF error");
exit(-1);
}
/*
* "enetfilter" supports only ethernets.
*/
*linktype = DLT_EN10MB;
return(if_fd);
}