/* $NetBSD: pcap-snit.c,v 1.7 2024/09/02 15:33:37 christos Exp $ */
/*
* Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Modifications made to accommodate the new SunOS4.0 NIT facility by
* Micky Liu,
[email protected], Columbia University in May, 1989.
* This module now handles the STREAMS based NIT.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: pcap-snit.c,v 1.7 2024/09/02 15:33:37 christos Exp $");
#include <config.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/timeb.h>
#include <sys/dir.h>
#include <sys/fcntlcom.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/stropts.h>
#include <net/if.h>
#include <net/nit.h>
#include <net/nit_if.h>
#include <net/nit_pf.h>
#include <net/nit_buf.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/if_ether.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/tcp.h>
#include <netinet/tcpip.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "pcap-int.h"
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
/*
* The chunk size for NIT. This is the amount of buffering
* done for read calls.
*/
#define CHUNKSIZE (2*1024)
/*
* The total buffer space used by NIT.
*/
#define BUFSPACE (4*CHUNKSIZE)
/* Forwards */
static int nit_setflags(int, int, int, char *);
/*
* Private data for capturing on STREAMS NIT devices.
*/
struct pcap_snit {
struct pcap_stat stat;
};
static int
pcap_stats_snit(pcap_t *p, struct pcap_stat *ps)
{
struct pcap_snit *psn = p->priv;
/*
* "ps_recv" counts packets handed to the filter, not packets
* that passed the filter. As filtering is done in userland,
* this does not include packets dropped because we ran out
* of buffer space.
*
* "ps_drop" counts packets dropped inside the "/dev/nit"
* device 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 or packets not yet read from libpcap by the
* application.
*/
*ps = psn->stat;
return (0);
}
static int
pcap_read_snit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
struct pcap_snit *psn = p->priv;
register int cc, n;
register u_char *bp, *cp, *ep;
register struct nit_bufhdr *hdrp;
register struct nit_iftime *ntp;
register struct nit_iflen *nlp;
register struct nit_ifdrops *ndp;
register int caplen;
cc = p->cc;
if (cc == 0) {
cc = read(p->fd, (char *)p->buffer, p->bufsize);
if (cc < 0) {
if (errno == EWOULDBLOCK)
return (0);
pcapint_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
errno, "pcap_read");
return (-1);
}
bp = (u_char *)p->buffer;
} else
bp = p->bp;
/*
* loop through each snapshot in the chunk
*
* This assumes that a single buffer of packets will have
* <= INT_MAX packets, so the packet count doesn't overflow.
*/
n = 0;
ep = bp + cc;
while (bp < 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 = bp;
p->cc = ep - bp;
return (n);
}
}
++psn->stat.ps_recv;
cp = bp;
/* get past NIT buffer */
hdrp = (struct nit_bufhdr *)cp;
cp += sizeof(*hdrp);
/* get past NIT timer */
ntp = (struct nit_iftime *)cp;
cp += sizeof(*ntp);
ndp = (struct nit_ifdrops *)cp;
psn->stat.ps_drop = ndp->nh_drops;
cp += sizeof *ndp;
/* get past packet len */
nlp = (struct nit_iflen *)cp;
cp += sizeof(*nlp);
/* next snapshot */
bp += hdrp->nhb_totlen;
caplen = nlp->nh_pktlen;
if (caplen > p->snapshot)
caplen = p->snapshot;
if (pcapint_filter(p->fcode.bf_insns, cp, nlp->nh_pktlen, caplen)) {
struct pcap_pkthdr h;
h.ts = ntp->nh_timestamp;
h.len = nlp->nh_pktlen;
h.caplen = caplen;
(*callback)(user, &h, cp);
if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
p->cc = ep - bp;
p->bp = bp;
return (n);
}
}
}
p->cc = 0;
return (n);
}
static int
pcap_inject_snit(pcap_t *p, const void *buf, int size)
{
struct strbuf ctl, data;
/*
* XXX - can we just do
*
ret = write(pd->f, buf, size);
*/
ctl.len = sizeof(*sa); /* XXX - what was this? */
ctl.buf = (char *)sa;
data.buf = buf;
data.len = size;
ret = putmsg(p->fd, &ctl, &data);
if (ret == -1) {
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "send");
return (-1);
}
return (ret);
}
static int
nit_setflags(pcap_t *p)
{
bpf_u_int32 flags;
struct strioctl si;
u_int zero = 0;
struct timeval timeout;
if (p->opt.immediate) {
/*
* Set the chunk size to zero, so that chunks get sent
* up immediately.
*/
si.ic_cmd = NIOCSCHUNK;
si.ic_len = sizeof(zero);
si.ic_dp = (char *)&zero;
if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "NIOCSCHUNK");
return (-1);
}
}
si.ic_timout = INFTIM;
if (p->opt.timeout != 0) {
timeout.tv_sec = p->opt.timeout / 1000;
timeout.tv_usec = (p->opt.timeout * 1000) % 1000000;
si.ic_cmd = NIOCSTIME;
si.ic_len = sizeof(timeout);
si.ic_dp = (char *)&timeout;
if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "NIOCSTIME");
return (-1);
}
}
flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
if (p->opt.promisc)
flags |= NI_PROMISC;
si.ic_cmd = NIOCSFLAGS;
si.ic_len = sizeof(flags);
si.ic_dp = (char *)&flags;
if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "NIOCSFLAGS");
return (-1);
}
return (0);
}
static int
pcap_activate_snit(pcap_t *p)
{
struct strioctl si; /* struct for ioctl() */
struct ifreq ifr; /* interface request struct */
int chunksize = CHUNKSIZE;
int fd;
static const char dev[] = "/dev/nit";
int err;
if (p->opt.rfmon) {
/*
* No monitor mode on SunOS 4.x (no Wi-Fi devices on
* hardware supported by SunOS 4.x).
*/
return (PCAP_ERROR_RFMON_NOTSUP);
}
/*
* Turn a negative snapshot value (invalid), a snapshot value of
* 0 (unspecified), or a value bigger than the normal maximum
* value, into the maximum allowed value.
*
* If some application really *needs* a bigger snapshot
* length, we should just increase MAXIMUM_SNAPLEN.
*/
if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
p->snapshot = MAXIMUM_SNAPLEN;
if (p->snapshot < 96)
/*
* NIT requires a snapshot length of at least 96.
*/
p->snapshot = 96;
/*
* Initially try a read/write open (to allow the inject
* method to work). If that fails due to permission
* issues, fall back to read-only. This allows a
* non-root user to be granted specific access to pcap
* capabilities via file permissions.
*
* XXX - we should have an API that has a flag that
* controls whether to open read-only or read-write,
* so that denial of permission to send (or inability
* to send, if sending packets isn't supported on
* the device in question) can be indicated at open
* time.
*/
p->fd = fd = open(dev, O_RDWR);
if (fd < 0 && errno == EACCES)
p->fd = fd = open(dev, O_RDONLY);
if (fd < 0) {
if (errno == EACCES) {
err = PCAP_ERROR_PERM_DENIED;
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"Attempt to open %s failed with EACCES - root privileges may be required",
dev);
} else {
err = PCAP_ERROR;
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "%s", dev);
}
goto bad;
}
/* arrange to get discrete messages from the STREAM and use NIT_BUF */
if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "I_SRDOPT");
err = PCAP_ERROR;
goto bad;
}
if (ioctl(fd, I_PUSH, "nbuf") < 0) {
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "push nbuf");
err = PCAP_ERROR;
goto bad;
}
/* set the chunksize */
si.ic_cmd = NIOCSCHUNK;
si.ic_timout = INFTIM;
si.ic_len = sizeof(chunksize);
si.ic_dp = (char *)&chunksize;
if (ioctl(fd, I_STR, (char *)&si) < 0) {
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "NIOCSCHUNK");
err = PCAP_ERROR;
goto bad;
}
/* request the interface */
strncpy(ifr.ifr_name, p->opt.device, sizeof(ifr.ifr_name));
ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
si.ic_cmd = NIOCBIND;
si.ic_len = sizeof(ifr);
si.ic_dp = (char *)𝔦
if (ioctl(fd, I_STR, (char *)&si) < 0) {
/*
* XXX - is there an error that means "no such device"?
* Is there one that means "that device doesn't support
* STREAMS NIT"?
*/
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "NIOCBIND: %s", ifr.ifr_name);
err = PCAP_ERROR;
goto bad;
}
/* set the snapshot length */
si.ic_cmd = NIOCSSNAP;
si.ic_len = sizeof(p->snapshot);
si.ic_dp = (char *)&p->snapshot;
if (ioctl(fd, I_STR, (char *)&si) < 0) {
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "NIOCSSNAP");
err = PCAP_ERROR;
goto bad;
}
if (nit_setflags(p) < 0) {
err = PCAP_ERROR;
goto bad;
}
(void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
/*
* NIT supports only ethernets.
*/
p->linktype = DLT_EN10MB;
p->bufsize = BUFSPACE;
p->buffer = malloc(p->bufsize);
if (p->buffer == NULL) {
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "malloc");
err = PCAP_ERROR;
goto bad;
}
/*
* "p->fd" is an FD for a STREAMS device, so "select()" and
* "poll()" should work on it.
*/
p->selectable_fd = p->fd;
/*
* 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 (p->dlt_list == NULL) {
pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
errno, "malloc");
err = PCAP_ERROR;
goto bad;
}
p->dlt_list[0] = DLT_EN10MB;
p->dlt_list[1] = DLT_DOCSIS;
p->dlt_count = 2;
p->read_op = pcap_read_snit;
p->inject_op = pcap_inject_snit;
p->setfilter_op = pcapint_install_bpf_program; /* no kernel filtering */
p->setdirection_op = NULL; /* Not implemented. */
p->set_datalink_op = NULL; /* can't change data link type */
p->getnonblock_op = pcapint_getnonblock_fd;
p->setnonblock_op = pcapint_setnonblock_fd;
p->stats_op = pcap_stats_snit;
return (0);
bad:
pcapint_cleanup_live_common(p);
return (err);
}
pcap_t *
pcapint_create_interface(const char *device _U_, char *ebuf)
{
pcap_t *p;
p = PCAP_CREATE_COMMON(ebuf, struct pcap_snit);
if (p == NULL)
return (NULL);
p->activate_op = pcap_activate_snit;
return (p);
}
/*
* XXX - there's probably a NIOCBIND error that means "that device
* doesn't support NIT"; if so, we should try an NIOCBIND and use that.
*/
static int
can_be_bound(const char *name _U_)
{
return (1);
}
static int
get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)
{
/*
* Nothing we can do.
* XXX - is there a way to find out whether an adapter has
* something plugged into it?
*/
return (0);
}
int
pcapint_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
{
return (pcapint_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
get_if_flags));
}
/*
* Libpcap version string.
*/
const char *
pcap_lib_version(void)
{
return (PCAP_VERSION_STRING);
}
