86Box/src/network/net_pcap.c

/*
 * VARCem	Virtual ARchaeological Computer EMulator.
 *		An emulator of (mostly) x86-based PC systems and devices,
 *		using the ISA,EISA,VLB,MCA  and PCI system buses, roughly
 *		spanning the era between 1981 and 1995.
 *
 *		This file is part of the VARCem Project.
 *
 *		Handle WinPcap library processing.
 *
 *
 *
 * Author:	Fred N. van Kempen, <decwiz@yahoo.com>
 *
 *		Copyright 2017-2019 Fred N. van Kempen.
 *
 *		Redistribution and  use  in source  and binary forms, with
 *		or  without modification, are permitted  provided that the
 *		following conditions are met:
 *
 *		1. Redistributions of  source  code must retain the entire
 *		   above notice, this list of conditions and the following
 *		   disclaimer.
 *
 *		2. Redistributions in binary form must reproduce the above
 *		   copyright  notice,  this list  of  conditions  and  the
 *		   following disclaimer in  the documentation and/or other
 *		   materials provided with the distribution.
 *
 *		3. Neither the  name of the copyright holder 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 BY THE  COPYRIGHT  HOLDERS AND CONTRIBUTORS
 * "AS IS" AND  ANY EXPRESS  OR  IMPLIED  WARRANTIES,  INCLUDING, BUT  NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE  ARE  DISCLAIMED. IN  NO  EVENT  SHALL THE COPYRIGHT
 * HOLDER OR  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL,  EXEMPLARY,  OR  CONSEQUENTIAL  DAMAGES  (INCLUDING,  BUT  NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE  GOODS OR SERVICES;  LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED  AND ON  ANY
 * THEORY OF  LIABILITY, WHETHER IN  CONTRACT, STRICT  LIABILITY, OR  TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING  IN ANY  WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <wchar.h>
#include <stdbool.h>
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#else
#include <poll.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/select.h>
#endif

#define HAVE_STDARG_H
#include <86box/86box.h>
#include <86box/device.h>
#include <86box/plat.h>
#include <86box/plat_dynld.h>
#include <86box/thread.h>
#include <86box/timer.h>
#include <86box/network.h>
#include <86box/net_event.h>

enum {
    NET_EVENT_STOP = 0,
    NET_EVENT_TX,
    NET_EVENT_RX,
    NET_EVENT_MAX
};

#ifdef __APPLE__
#include <pcap/pcap.h>
#else
typedef int bpf_int32;
typedef unsigned int bpf_u_int32;

/*
 * The instruction data structure.
 */
struct bpf_insn {
    unsigned short  code;
    unsigned char   jt;
    unsigned char   jf;
    bpf_u_int32     k;
};

/*
 * Structure for "pcap_compile()", "pcap_setfilter()", etc..
 */
struct bpf_program {
    unsigned int    bf_len;
    struct bpf_insn *bf_insns;
};

typedef struct pcap_if  pcap_if_t;

#define PCAP_ERRBUF_SIZE    256

struct pcap_pkthdr {
    struct timeval  ts;
    bpf_u_int32     caplen;
    bpf_u_int32     len;
};

struct pcap_if {
    struct pcap_if *next;
    char *name;
    char *description;
    void *addresses;
    bpf_u_int32 flags;
};
#endif

typedef struct {
    void      *pcap; /* handle to pcap lib instance */
    netcard_t *card; /* netcard linked to us */
    thread_t  *poll_tid;
    net_evt_t  tx_event;
    net_evt_t  stop_event;
    netpkt_t   pkt;
    uint8_t    mac_addr[6];
} net_pcap_t;

typedef struct {
    char    *intf_name;
    uint8_t *mac_addr;
} net_pcap_params_t;

static volatile void *libpcap_handle;	/* handle to WinPcap DLL */

/* Pointers to the real functions. */
static const char	*(*f_pcap_lib_version)(void);
static int    (*f_pcap_findalldevs)(pcap_if_t **,char *);
static void   (*f_pcap_freealldevs)(void *);
static void	 *(*f_pcap_open_live)(const char *,int,int,int,char *);
static int    (*f_pcap_compile)(void *,void *, const char *,int,bpf_u_int32);
static int    (*f_pcap_setfilter)(void *,void *);
static const unsigned char
             *(*f_pcap_next)(void *,void *);
static int	  (*f_pcap_sendpacket)(void *,const unsigned char *,int);
static void	  (*f_pcap_close)(void *);
static int    (*f_pcap_setnonblock)(void*, int, char*);
static int    (*f_pcap_set_immediate_mode)(void *, int);
static int    (*f_pcap_set_promisc)(void *, int);
static int    (*f_pcap_set_snaplen)(void *, int);
static void  *(*f_pcap_create)(const char *, char*);
static int    (*f_pcap_activate)(void *);
static void  *(*f_pcap_geterr)(void *);
#ifdef _WIN32
static HANDLE (*f_pcap_getevent)(void *);
#else
static int    (*f_pcap_get_selectable_fd)(void *);
#endif

static dllimp_t pcap_imports[] = {
    { "pcap_lib_version",        &f_pcap_lib_version       },
    { "pcap_findalldevs",        &f_pcap_findalldevs       },
    { "pcap_freealldevs",        &f_pcap_freealldevs       },
    { "pcap_open_live",          &f_pcap_open_live         },
    { "pcap_compile",            &f_pcap_compile           },
    { "pcap_setfilter",          &f_pcap_setfilter         },
    { "pcap_next",               &f_pcap_next              },
    { "pcap_sendpacket",         &f_pcap_sendpacket        },
    { "pcap_close",              &f_pcap_close             },
    { "pcap_setnonblock",        &f_pcap_setnonblock       },
    { "pcap_set_immediate_mode", &f_pcap_set_immediate_mode},
    { "pcap_set_promisc",        &f_pcap_set_promisc       },
    { "pcap_set_snaplen",        &f_pcap_set_snaplen       },
    { "pcap_create",             &f_pcap_create            },
    { "pcap_activate",           &f_pcap_activate          },
    { "pcap_geterr",             &f_pcap_geterr            },
#ifdef _WIN32
    { "pcap_getevent",           &f_pcap_getevent          },
#else
    { "pcap_get_selectable_fd", &f_pcap_get_selectable_fd },
#endif
    { NULL,                      NULL                      },
};

#ifdef ENABLE_PCAP_LOG
int pcap_do_log = ENABLE_PCAP_LOG;

static void
pcap_log(const char *fmt, ...)
{
    va_list ap;

    if (pcap_do_log) {
	va_start(ap, fmt);
	pclog_ex(fmt, ap);
	va_end(ap);
    }
}
#else
#define pcap_log(fmt, ...)
#endif


static void
net_pcap_read_packet(net_pcap_t *pcap)
{
    struct pcap_pkthdr h;

    uint8_t *data = (uint8_t *) f_pcap_next((void *) pcap->pcap, &h);
    if (!data)
        return;

    network_rx_put(pcap->card, data, h.caplen);
}

/* Send a packet to the Pcap interface. */
void
net_pcap_in(void *pcap, uint8_t *bufp, int len)
{
    if (pcap == NULL)
    return;

    f_pcap_sendpacket((void *)pcap, bufp, len);
}

void
net_pcap_in_available(void *priv)
{
    net_pcap_t *pcap = (net_pcap_t *)priv;
    net_event_set(&pcap->tx_event);
}

#ifdef _WIN32
static void
net_pcap_thread(void *priv)
{
    net_pcap_t *pcap = (net_pcap_t*)priv;

    pcap_log("PCAP: polling started.\n");

    HANDLE events[NET_EVENT_MAX];
    events[NET_EVENT_STOP] = net_event_get_handle(&pcap->stop_event);
    events[NET_EVENT_TX] = net_event_get_handle(&pcap->tx_event);
    events[NET_EVENT_RX] = f_pcap_getevent((void *)pcap->pcap);

    bool run = true;

    while (run) {
        int ret = WaitForMultipleObjects(NET_EVENT_MAX, events, FALSE, INFINITE);

        switch (ret - WAIT_OBJECT_0) {
            case NET_EVENT_STOP:
                net_event_clear(&pcap->stop_event);
                run = false;
                break;

            case NET_EVENT_TX:
                net_event_clear(&pcap->tx_event);
                while (network_tx_pop(pcap->card, &pcap->pkt)) {
                    net_pcap_in(pcap->pcap, pcap->pkt.data, pcap->pkt.len);
                }
                break;

            case NET_EVENT_RX:
                net_pcap_read_packet(pcap);
                break;
        }
    }

    pcap_log("PCAP: polling stopped.\n");
}
#else
static void
net_pcap_thread(void *priv)
{
    net_pcap_t *pcap = (net_pcap_t*)priv;

    pcap_log("PCAP: polling started.\n");

    struct pollfd pfd[NET_EVENT_MAX];
    pfd[NET_EVENT_STOP].fd     = net_event_get_fd(&pcap->stop_event);
    pfd[NET_EVENT_STOP].events = POLLIN | POLLPRI;

    pfd[NET_EVENT_TX].fd     = net_event_get_fd(&pcap->tx_event);
    pfd[NET_EVENT_TX].events = POLLIN | POLLPRI;

    pfd[NET_EVENT_RX].fd     = f_pcap_get_selectable_fd((void *) pcap->pcap);
    pfd[NET_EVENT_RX].events = POLLIN | POLLPRI;

    /* As long as the channel is open.. */
    while (1) {
        poll(pfd, NET_EVENT_MAX, -1);

        if (pfd[NET_EVENT_STOP].revents & POLLIN) {
            net_event_clear(&pcap->stop_event);
            break;
        }

        if (pfd[NET_EVENT_TX].revents & POLLIN) {
            net_event_clear(&pcap->tx_event);

            if (network_tx_pop(pcap->card, &pcap->pkt)) {
                net_pcap_in(pcap->pcap, pcap->pkt.data, pcap->pkt.len);
            }
        }

        if (pfd[NET_EVENT_RX].revents & POLLIN) {
            net_pcap_read_packet(pcap);
        }

    }

    pcap_log("PCAP: polling stopped.\n");
}
#endif

/*
 * Prepare the (Win)Pcap module for use.
 *
 * This is called only once, during application init,
 * to check for availability of PCAP, and to retrieve
 * a list of (usable) intefaces for it.
 */
int
net_pcap_prepare(netdev_t *list)
{
    char errbuf[PCAP_ERRBUF_SIZE];
    pcap_if_t *devlist, *dev;
    int i = 0;

    /* Try loading the DLL. */
#ifdef _WIN32
    libpcap_handle = dynld_module("wpcap.dll", pcap_imports);
#elif defined __APPLE__
    libpcap_handle = dynld_module("libpcap.dylib", pcap_imports);
#else
    libpcap_handle = dynld_module("libpcap.so", pcap_imports);
#endif
    if (libpcap_handle == NULL) {
        pcap_log("PCAP: error loading pcap module\n");
        return(-1);
    }

    /* Retrieve the device list from the local machine */
    if (f_pcap_findalldevs(&devlist, errbuf) == -1) {
	pcap_log("PCAP: error in pcap_findalldevs: %s\n", errbuf);
	return(-1);
    }

    for (dev=devlist; dev!=NULL; dev=dev->next) {
		if (i >= (NET_HOST_INTF_MAX - 1))
			break;

		/**
		 * we initialize the strings to NULL first for strncpy
		 */

		memset(list->device, '\0', sizeof(list->device));
		memset(list->description, '\0', sizeof(list->description));

		strncpy(list->device, dev->name, sizeof(list->device) - 1);
		if (dev->description) {
			strncpy(list->description, dev->description, sizeof(list->description) - 1);
		} else {
			/* if description is NULL, set the name. This allows pcap to display *something* useful under WINE */
			strncpy(list->description, dev->name, sizeof(list->description) - 1);
		}

	list++; i++;
    }

    /* Release the memory. */
    f_pcap_freealldevs(devlist);

    return(i);
}


/*
 * Initialize (Win)Pcap for use.
 *
 * We already know we have PCAP available, as this
 * is called when the network activates itself and
 * tries to attach to the network module.
 */
void *
net_pcap_init(const netcard_t *card, const uint8_t *mac_addr, void *priv)
{
    char  errbuf[PCAP_ERRBUF_SIZE];
    char *str;
    char filter_exp[255];
    struct bpf_program fp;

    char *intf_name = (char*)priv;

    /* Did we already load the library? */
    if (libpcap_handle == NULL) {
        pcap_log("PCAP: net_pcap_init without handle.\n");
        return NULL;
    }

    /* Get the PCAP library name and version. */
    strcpy(errbuf, f_pcap_lib_version());
    str = strchr(errbuf, '(');
    if (str != NULL)
        *(str - 1) = '\0';
    pcap_log("PCAP: initializing, %s\n", errbuf);

    /* Get the value of our capture interface. */
    if ((intf_name[0] == '\0') || !strcmp(intf_name, "none")) {
        pcap_log("PCAP: no interface configured!\n");
        return NULL;
    }

    pcap_log("PCAP: interface: %s\n", intf_name);

    net_pcap_t *pcap = calloc(1, sizeof(net_pcap_t));
    pcap->card = (netcard_t *)card;
    memcpy(pcap->mac_addr, mac_addr, sizeof(pcap->mac_addr));

    if ((pcap->pcap = f_pcap_create(intf_name, errbuf)) == NULL) {
        pcap_log(" Unable to open device: %s!\n", intf_name);
        free(pcap);
        return NULL;
    }

    if (f_pcap_setnonblock((void *) pcap->pcap, 1, errbuf) != 0)
        pcap_log("PCAP: failed nonblock %s\n", errbuf);

    if (f_pcap_set_immediate_mode((void *) pcap->pcap, 1) != 0)
        pcap_log("PCAP: error setting immediate mode\n");

    if (f_pcap_set_promisc((void *) pcap->pcap, 1) != 0)
        pcap_log("PCAP: error enabling promiscuous mode\n");

    if (f_pcap_set_snaplen((void *) pcap->pcap, NET_MAX_FRAME) != 0)
        pcap_log("PCAP: error setting snaplen\n");

    if (f_pcap_activate((void *) pcap->pcap) != 0) {
        pcap_log("PCAP: failed pcap_activate");
        f_pcap_close((void *) pcap->pcap);
        free(pcap);
        return NULL;
    }

    /* Create a MAC address based packet filter. */
    pcap_log("PCAP: installing filter for MAC=%02x:%02x:%02x:%02x:%02x:%02x\n",
             mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
    sprintf(filter_exp,
            "( ((ether dst ff:ff:ff:ff:ff:ff) or (ether dst %02x:%02x:%02x:%02x:%02x:%02x)) and not (ether src %02x:%02x:%02x:%02x:%02x:%02x) )",
            mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5],
            mac_addr[0], mac_addr[1], mac_addr[2], mac_addr[3], mac_addr[4], mac_addr[5]);
    if (f_pcap_compile((void *) pcap->pcap, &fp, filter_exp, 0, 0xffffffff) != -1) {
        if (f_pcap_setfilter((void *) pcap->pcap, &fp) != 0) {
            pcap_log("PCAP: error installing filter (%s) !\n", filter_exp);
            f_pcap_close((void *) pcap->pcap);
            free(pcap);
            return NULL;
        }
    } else {
        pcap_log("PCAP: could not compile filter (%s) : %s!\n", filter_exp, f_pcap_geterr((void*)pcap->pcap));
        f_pcap_close((void *) pcap->pcap);
        free(pcap);
        return NULL;
    }

    pcap->pkt.data = calloc(1, NET_MAX_FRAME);
    net_event_init(&pcap->tx_event);
    net_event_init(&pcap->stop_event);
    pcap->poll_tid = thread_create(net_pcap_thread, pcap);

    return pcap;
}

/* Close up shop. */
void
net_pcap_close(void *priv)
{
    if (!priv)
        return;

    net_pcap_t *pcap = (net_pcap_t *)priv;

    pcap_log("PCAP: closing.\n");

    /* Tell the thread to terminate. */
    net_event_set(&pcap->stop_event);

    /* Wait for the thread to finish. */
    pcap_log("PCAP: waiting for thread to end...\n");
    thread_wait(pcap->poll_tid);
    pcap_log("PCAP: thread ended\n");

    free(pcap->pkt.data);

    /* OK, now shut down Pcap itself. */
    f_pcap_close((void*)pcap->pcap);

    net_event_close(&pcap->tx_event);
    net_event_close(&pcap->stop_event);

    free(pcap);
}

const netdrv_t net_pcap_drv = {
    &net_pcap_in_available,
    &net_pcap_init,
    &net_pcap_close,
    NULL
};