pcap-nit.c

/*
 * 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/types.h>
#include <sys/time.h>
#include <sys/timeb.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>

#include <net/if.h>
#include <net/nit.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 <ctype.h>
#include <errno.h>
#include <stdio.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 NIT devices.
 */
struct pcap_nit {
    struct pcap_stat stat;
};

static int
pcap_stats_nit(pcap_t *p, struct pcap_stat *ps)
{
    struct pcap_nit *pn = 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" presumably counts packets dropped by the socket
     * because of flow control requirements or resource exhaustion;
     * it doesn't count packets dropped by the interface driver.
     * 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 = pn->stat;
    return (0);
}

static int
pcap_read_nit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
    struct pcap_nit *pn = p->priv;
    register int cc, n;
    register u_char *bp, *cp, *ep;
    register struct nit_hdr *nh;
    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_snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
                pcap_strerror(errno));
            return (-1);
        }
        bp = (u_char *)p->buffer;
    } else
        bp = p->bp;

    /*
     * Loop through each packet.  The increment expression
     * rounds up to the next int boundary past the end of
     * the previous packet.
     */
    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->cc = ep - bp;
                p->bp = bp;
                return (n);
            }
        }

        nh = (struct nit_hdr *)bp;
        cp = bp + sizeof(*nh);

        switch (nh->nh_state) {

        case NIT_CATCH:
            break;

        case NIT_NOMBUF:
        case NIT_NOCLUSTER:
        case NIT_NOSPACE:
            pn->stat.ps_drop = nh->nh_dropped;
            continue;

        case NIT_SEQNO:
            continue;

        default:
            pcap_snprintf(p->errbuf, sizeof(p->errbuf),
                "bad nit state %d", nh->nh_state);
            return (-1);
        }
        ++pn->stat.ps_recv;
        bp += ((sizeof(struct nit_hdr) + nh->nh_datalen +
            sizeof(int) - 1) & ~(sizeof(int) - 1));

        caplen = nh->nh_wirelen;
        if (caplen > p->snapshot)
            caplen = p->snapshot;
        if (bpf_filter(p->fcode.bf_insns, cp, nh->nh_wirelen, caplen)) {
            struct pcap_pkthdr h;
            h.ts = nh->nh_timestamp;
            h.len = nh->nh_wirelen;
            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_nit(pcap_t *p, const void *buf, size_t size)
{
    struct sockaddr sa;
    int ret;

    memset(&sa, 0, sizeof(sa));
    strncpy(sa.sa_data, device, sizeof(sa.sa_data));
    ret = sendto(p->fd, buf, size, 0, &sa, sizeof(sa));
    if (ret == -1) {
        pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
            pcap_strerror(errno));
        return (-1);
    }
    return (ret);
}

static int
nit_setflags(pcap_t *p)
{
    struct nit_ioc nioc;

    memset(&nioc, 0, sizeof(nioc));
    nioc.nioc_typetomatch = NT_ALLTYPES;
    nioc.nioc_snaplen = p->snapshot;
    nioc.nioc_bufalign = sizeof(int);
    nioc.nioc_bufoffset = 0;

    if (p->opt.buffer_size != 0)
        nioc.nioc_bufspace = p->opt.buffer_size;
    else {
        /* Default buffer size */
        nioc.nioc_bufspace = BUFSPACE;
    }

    if (p->opt.immediate) {
        /*
         * XXX - will this cause packets to be delivered immediately?
         * XXX - given that this is for SunOS prior to 4.0, do
         * we care?
         */
        nioc.nioc_chunksize = 0;
    } else
        nioc.nioc_chunksize = CHUNKSIZE;
    if (p->opt.timeout != 0) {
        nioc.nioc_flags |= NF_TIMEOUT;
        nioc.nioc_timeout.tv_sec = p->opt.timeout / 1000;
        nioc.nioc_timeout.tv_usec = (p->opt.timeout * 1000) % 1000000;
    }
    if (p->opt.promisc)
        nioc.nioc_flags |= NF_PROMISC;

    if (ioctl(p->fd, SIOCSNIT, &nioc) < 0) {
        pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCSNIT: %s",
            pcap_strerror(errno));
        return (-1);
    }
    return (0);
}

static int
pcap_activate_nit(pcap_t *p)
{
    int fd;
    struct sockaddr_nit snit;

    if (p->opt.rfmon) {
        /*
         * No monitor mode on SunOS 3.x or earlier (no
         * Wi-Fi *devices* for the hardware that supported
         * them!).
         */
        return (PCAP_ERROR_RFMON_NOTSUP);
    }

    if (p->snapshot < 96)
        /*
         * NIT requires a snapshot length of at least 96.
         */
        p->snapshot = 96;

    memset(p, 0, sizeof(*p));
    p->fd = fd = socket(AF_NIT, SOCK_RAW, NITPROTO_RAW);
    if (fd < 0) {
        pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
            "socket: %s", pcap_strerror(errno));
        goto bad;
    }
    snit.snit_family = AF_NIT;
    (void)strncpy(snit.snit_ifname, p->opt.source, NITIFSIZ);

    if (bind(fd, (struct sockaddr *)&snit, sizeof(snit))) {
        pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
            "bind: %s: %s", snit.snit_ifname, pcap_strerror(errno));
        goto bad;
    }
    if (nit_setflags(p) < 0)
        goto bad;

    /*
     * NIT supports only ethernets.
     */
    p->linktype = DLT_EN10MB;

    p->bufsize = BUFSPACE;
    p->buffer = malloc(p->bufsize);
    if (p->buffer == NULL) {
        strlcpy(p->errbuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
        goto bad;
    }

    /*
     * "p->fd" is a socket, so "select()" 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_nit;
    p->inject_op = pcap_inject_nit;
    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_nit;

    return (0);
 bad:
    pcap_cleanup_live_common(p);
    return (PCAP_ERROR);
}

pcap_t *
pcap_create_interface(const char *device, char *ebuf)
{
    pcap_t *p;

    p = pcap_create_common(device, ebuf, sizeof (struct pcap_nit));
    if (p == NULL)
        return (NULL);

    p->activate_op = pcap_activate_nit;
    return (p);
}

int
pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
{
    return (0);
}