nexmon – Rev 1
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/*
* This code is derived from code formerly in pcap-dlpi.c, originally
* contributed by Atanu Ghosh (atanu@cs.ucl.ac.uk), University College
* London, and subsequently modified by Guy Harris (guy@alum.mit.edu),
* Mark Pizzolato <List-tcpdump-workers@subscriptions.pizzolato.net>,
* Mark C. Brown (mbrown@hp.com), and Sagun Shakya <Sagun.Shakya@Sun.COM>.
*/
/*
* This file contains dlpi/libdlpi related common functions used
* by pcap-[dlpi,libdlpi].c.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifndef DL_IPATM
#define DL_IPATM 0x12 /* ATM Classical IP interface */
#endif
#ifdef HAVE_SYS_BUFMOD_H
/*
* Size of a bufmod chunk to pass upstream; that appears to be the
* biggest value to which you can set it, and setting it to that value
* (which is bigger than what appears to be the Solaris default of 8192)
* reduces the number of packet drops.
*/
#define CHUNKSIZE 65536
/*
* Size of the buffer to allocate for packet data we read; it must be
* large enough to hold a chunk.
*/
#define PKTBUFSIZE CHUNKSIZE
#else /* HAVE_SYS_BUFMOD_H */
/*
* Size of the buffer to allocate for packet data we read; this is
* what the value used to be - there's no particular reason why it
* should be tied to MAXDLBUF, but we'll leave it as this for now.
*/
#define MAXDLBUF 8192
#define PKTBUFSIZE (MAXDLBUF * sizeof(bpf_u_int32))
#endif
#include <sys/types.h>
#include <sys/time.h>
#ifdef HAVE_SYS_BUFMOD_H
#include <sys/bufmod.h>
#endif
#include <sys/dlpi.h>
#include <sys/stream.h>
#include <errno.h>
#include <memory.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stropts.h>
#include <unistd.h>
#ifdef HAVE_LIBDLPI
#include <libdlpi.h>
#endif
#include "pcap-int.h"
#include "dlpisubs.h"
#ifdef HAVE_SYS_BUFMOD_H
static void pcap_stream_err(const char *, int, char *);
#endif
/*
* Get the packet statistics.
*/
int
pcap_stats_dlpi(pcap_t *p, struct pcap_stat *ps)
{
struct pcap_dlpi *pd = p->priv;
/*
* "ps_recv" counts packets handed to the filter, not packets
* that passed the filter. As filtering is done in userland,
* this would not include packets dropped because we ran out
* of buffer space; in order to make this more like other
* platforms (Linux 2.4 and later, BSDs with BPF), where the
* "packets received" count includes packets received but dropped
* due to running out of buffer space, and to keep from confusing
* applications that, for example, compute packet drop percentages,
* we also make it count packets dropped by "bufmod" (otherwise we
* might run the risk of the packet drop count being bigger than
* the received-packet count).
*
* "ps_drop" counts packets dropped by "bufmod" because of
* flow control requirements or resource exhaustion; it doesn't
* count packets dropped by the interface driver, or packets
* dropped upstream. As filtering is done in userland, it counts
* packets regardless of whether they would've passed the filter.
*
* These statistics don't include packets not yet read from
* the kernel by libpcap, but they may include packets not
* yet read from libpcap by the application.
*/
*ps = pd->stat;
/*
* Add in the drop count, as per the above comment.
*/
ps->ps_recv += ps->ps_drop;
return (0);
}
/*
* Loop through the packets and call the callback for each packet.
* Return the number of packets read.
*/
int
pcap_process_pkts(pcap_t *p, pcap_handler callback, u_char *user,
int count, u_char *bufp, int len)
{
struct pcap_dlpi *pd = p->priv;
int n, caplen, origlen;
u_char *ep, *pk;
struct pcap_pkthdr pkthdr;
#ifdef HAVE_SYS_BUFMOD_H
struct sb_hdr *sbp;
#ifdef LBL_ALIGN
struct sb_hdr sbhdr;
#endif
#endif
/* Loop through packets */
ep = bufp + len;
n = 0;
#ifdef HAVE_SYS_BUFMOD_H
while (bufp < ep) {
/*
* Has "pcap_breakloop()" been called?
* If so, return immediately - if we haven't read any
* packets, clear the flag and return -2 to indicate
* that we were told to break out of the loop, otherwise
* leave the flag set, so that the *next* call will break
* out of the loop without having read any packets, and
* return the number of packets we've processed so far.
*/
if (p->break_loop) {
if (n == 0) {
p->break_loop = 0;
return (-2);
} else {
p->bp = bufp;
p->cc = ep - bufp;
return (n);
}
}
#ifdef LBL_ALIGN
if ((long)bufp & 3) {
sbp = &sbhdr;
memcpy(sbp, bufp, sizeof(*sbp));
} else
#endif
sbp = (struct sb_hdr *)bufp;
pd->stat.ps_drop = sbp->sbh_drops;
pk = bufp + sizeof(*sbp);
bufp += sbp->sbh_totlen;
origlen = sbp->sbh_origlen;
caplen = sbp->sbh_msglen;
#else
origlen = len;
caplen = min(p->snapshot, len);
pk = bufp;
bufp += caplen;
#endif
++pd->stat.ps_recv;
if (bpf_filter(p->fcode.bf_insns, pk, origlen, caplen)) {
#ifdef HAVE_SYS_BUFMOD_H
pkthdr.ts.tv_sec = sbp->sbh_timestamp.tv_sec;
pkthdr.ts.tv_usec = sbp->sbh_timestamp.tv_usec;
#else
(void) gettimeofday(&pkthdr.ts, NULL);
#endif
pkthdr.len = origlen;
pkthdr.caplen = caplen;
/* Insure caplen does not exceed snapshot */
if (pkthdr.caplen > p->snapshot)
pkthdr.caplen = p->snapshot;
(*callback)(user, &pkthdr, pk);
if (++n >= count && !PACKET_COUNT_IS_UNLIMITED(count)) {
p->cc = ep - bufp;
p->bp = bufp;
return (n);
}
}
#ifdef HAVE_SYS_BUFMOD_H
}
#endif
p->cc = 0;
return (n);
}
/*
* Process the mac type. Returns -1 if no matching mac type found, otherwise 0.
*/
int
pcap_process_mactype(pcap_t *p, u_int mactype)
{
int retv = 0;
switch (mactype) {
case DL_CSMACD:
case DL_ETHER:
p->linktype = DLT_EN10MB;
p->offset = 2;
/*
* This is (presumably) a real Ethernet capture; give it a
* link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
* that an application can let you choose it, in case you're
* capturing DOCSIS traffic that a Cisco Cable Modem
* Termination System is putting out onto an Ethernet (it
* doesn't put an Ethernet header onto the wire, it puts raw
* DOCSIS frames out on the wire inside the low-level
* Ethernet framing).
*/
p->dlt_list = (u_int *)malloc(sizeof(u_int) * 2);
/*
* If that fails, just leave the list empty.
*/
if (p->dlt_list != NULL) {
p->dlt_list[0] = DLT_EN10MB;
p->dlt_list[1] = DLT_DOCSIS;
p->dlt_count = 2;
}
break;
case DL_FDDI:
p->linktype = DLT_FDDI;
p->offset = 3;
break;
case DL_TPR:
/* XXX - what about DL_TPB? Is that Token Bus? */
p->linktype = DLT_IEEE802;
p->offset = 2;
break;
#ifdef HAVE_SOLARIS
case DL_IPATM:
p->linktype = DLT_SUNATM;
p->offset = 0; /* works for LANE and LLC encapsulation */
break;
#endif
default:
snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "unknown mactype %u",
mactype);
retv = -1;
}
return (retv);
}
#ifdef HAVE_SYS_BUFMOD_H
/*
* Push and configure the buffer module. Returns -1 for error, otherwise 0.
*/
int
pcap_conf_bufmod(pcap_t *p, int snaplen)
{
struct timeval to;
bpf_u_int32 ss, chunksize;
/* Non-standard call to get the data nicely buffered. */
if (ioctl(p->fd, I_PUSH, "bufmod") != 0) {
pcap_stream_err("I_PUSH bufmod", errno, p->errbuf);
return (-1);
}
ss = snaplen;
if (ss > 0 &&
strioctl(p->fd, SBIOCSSNAP, sizeof(ss), (char *)&ss) != 0) {
pcap_stream_err("SBIOCSSNAP", errno, p->errbuf);
return (-1);
}
if (p->opt.immediate) {
/* Set the timeout to zero, for immediate delivery. */
to.tv_sec = 0;
to.tv_usec = 0;
if (strioctl(p->fd, SBIOCSTIME, sizeof(to), (char *)&to) != 0) {
pcap_stream_err("SBIOCSTIME", errno, p->errbuf);
return (-1);
}
} else {
/* Set up the bufmod timeout. */
if (p->opt.timeout != 0) {
to.tv_sec = p->opt.timeout / 1000;
to.tv_usec = (p->opt.timeout * 1000) % 1000000;
if (strioctl(p->fd, SBIOCSTIME, sizeof(to), (char *)&to) != 0) {
pcap_stream_err("SBIOCSTIME", errno, p->errbuf);
return (-1);
}
}
/* Set the chunk length. */
chunksize = CHUNKSIZE;
if (strioctl(p->fd, SBIOCSCHUNK, sizeof(chunksize), (char *)&chunksize)
!= 0) {
pcap_stream_err("SBIOCSCHUNKP", errno, p->errbuf);
return (-1);
}
}
return (0);
}
#endif /* HAVE_SYS_BUFMOD_H */
/*
* Allocate data buffer. Returns -1 if memory allocation fails, else 0.
*/
int
pcap_alloc_databuf(pcap_t *p)
{
p->bufsize = PKTBUFSIZE;
p->buffer = (u_char *)malloc(p->bufsize + p->offset);
if (p->buffer == NULL) {
strlcpy(p->errbuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
return (-1);
}
return (0);
}
/*
* Issue a STREAMS I_STR ioctl. Returns -1 on error, otherwise
* length of returned data on success.
*/
int
strioctl(int fd, int cmd, int len, char *dp)
{
struct strioctl str;
int retv;
str.ic_cmd = cmd;
str.ic_timout = -1;
str.ic_len = len;
str.ic_dp = dp;
if ((retv = ioctl(fd, I_STR, &str)) < 0)
return (retv);
return (str.ic_len);
}
#ifdef HAVE_SYS_BUFMOD_H
/*
* Write stream error message to errbuf.
*/
static void
pcap_stream_err(const char *func, int err, char *errbuf)
{
snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", func, pcap_strerror(err));
}
#endif