pcap-snit.c

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/*
 * 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, micky@cunixc.cc.columbia.edu, Columbia University in May, 1989.
 * This module now handles the STREAMS based NIT.
 */
 
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
 
#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);
            pcap_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
     */
    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 (pcap_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) {
        pcap_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) {
            pcap_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) {
            pcap_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) {
        pcap_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;
        else
            err = PCAP_ERROR;
        pcap_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) {
        pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
            errno, "I_SRDOPT");
        err = PCAP_ERROR;
        goto bad;
    }
    if (ioctl(fd, I_PUSH, "nbuf") < 0) {
        pcap_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) {
        pcap_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 *)&ifr;
    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"?
         */
        pcap_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) {
        pcap_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) {
        pcap_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 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;
    }
 
    p->read_op = pcap_read_snit;
    p->inject_op = pcap_inject_snit;
    p->setfilter_op = 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 = pcap_getnonblock_fd;
    p->setnonblock_op = pcap_setnonblock_fd;
    p->stats_op = pcap_stats_snit;
 
    return (0);
 bad:
    pcap_cleanup_live_common(p);
    return (err);
}
 
pcap_t *
pcap_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
pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
{
    return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
        get_if_flags));
}
 
/*
 * Libpcap version string.
 */
const char *
pcap_lib_version(void)
{
    return (PCAP_VERSION_STRING);
}