CI: Call print_so_deps() on rpcapd in remote enabled build

[libpcap] / pcap-dag.c

/*
 * pcap-dag.c: Packet capture interface for Endace DAG cards.
 *
 * Authors: Richard Littin, Sean Irvine ({richard,sean}@reeltwo.com)
 * Modifications: Jesper Peterson
 *                Koryn Grant
 *                Stephen Donnelly <stephen.donnelly@endace.com>
 */

#include <config.h>

#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <endian.h>
#include <limits.h>
#include <unistd.h>

#include "pcap-int.h"

#if __BYTE_ORDER == __BIG_ENDIAN
// Will need SWAPLL().
#include "pcap-util.h"
#endif

#include "dagapi.h"
#include "dagpci.h"
#include "dag_config_api.h"

#include "pcap-dag.h"

/*
 * DAG devices have names beginning with "dag", followed by a number
 * from 0 to DAG_MAX_BOARDS, then optionally a colon and a stream number
 * from 0 to DAG_STREAM_MAX.
 */
#ifndef DAG_MAX_BOARDS
#define DAG_MAX_BOARDS 32
#endif

#define ATM_CELL_SIZE           52
#define ATM_HDR_SIZE            4

/*
 * A header containing additional MTP information.
 */
#define MTP2_SENT_OFFSET                0       /* 1 byte */
#define MTP2_ANNEX_A_USED_OFFSET        1       /* 1 byte */
#define MTP2_LINK_NUMBER_OFFSET         2       /* 2 bytes */
#define MTP2_HDR_LEN                    4       /* length of the header */

#define MTP2_ANNEX_A_NOT_USED      0
#define MTP2_ANNEX_A_USED          1
#define MTP2_ANNEX_A_USED_UNKNOWN  2

/* SunATM pseudo header */
struct sunatm_hdr {
        unsigned char   flags;          /* destination and traffic type */
        unsigned char   vpi;            /* VPI */
        unsigned short  vci;            /* VCI */
};

/*
 * Private data for capturing on DAG devices.
 */
struct pcap_dag {
        struct pcap_stat stat;
        u_char  *dag_mem_bottom;        /* DAG card current memory bottom pointer */
        u_char  *dag_mem_top;   /* DAG card current memory top pointer */
        int     dag_fcs_bits;   /* Number of checksum bits from link layer */
        int     dag_flags;      /* Flags */
        int     dag_devnum;     /* This is the N in "dagN" or "dagN:M". */
        int     dag_stream;     /* And this is the M. */
        int     dag_timeout;    /* timeout specified to pcap_open_live.
                                 * Same as in linux above, introduce
                                 * generally? */
        dag_card_ref_t dag_ref; /* DAG Configuration/Status API card reference */
        dag_component_t dag_root;       /* DAG CSAPI Root component */
        attr_uuid_t drop_attr;  /* DAG Stream Drop Attribute handle, if available */
        uint64_t drop_base;     // Rx stream drop counter initial value.
        struct timeval required_select_timeout;
                                /* Timeout caller must use in event loops */
        uint8_t tx_iface;       // Tx interface number
        uint8_t tx_align_bytes; /* If necessary, add trailing padding to an
                                 * ERF record to make it a multiple of this
                                 * many bytes long.  DAG API calls this "ERF
                                 * record alignment". */
        uint8_t terf_fcs_bytes; // How many FCS bytes TERF is expecting.
};

#define ALIGN_BYTES_DEFAULT 8
#define ALIGN_BYTES_9_2 16
#define ALIGN_BYTES_MAX ALIGN_BYTES_9_2

typedef struct pcap_dag_node {
        struct pcap_dag_node *next;
        pcap_t *p;
        pid_t pid;
} pcap_dag_node_t;

static pcap_dag_node_t *pcap_dags = NULL;
static int atexit_handler_installed = 0;

#define MAX_DAG_PACKET 65536

static unsigned char TempPkt[MAX_DAG_PACKET];

#define TX_ONLY(stream) ((stream) % 2)
#define RX_ONLY(stream) (! TX_ONLY(stream))
#define RXTX_STR(stream) (TX_ONLY(stream) ? "Tx" : "Rx")

static int dag_stats(pcap_t *p, struct pcap_stat *ps);
static int dag_set_datalink(pcap_t *p, int dlt);
static int dag_get_datalink(pcap_t *p);
static int dag_setnonblock(pcap_t *p, int nonblock);

// Environment variables that can control behaviour of this libpcap module.
#define ENV_RX_FCS_BITS "ERF_FCS_BITS"
#define ENV_RX_FCS_NOSTRIP "ERF_DONT_STRIP_FCS"
#define ENV_TX_IFACE "ERF_TX_INTERFACE"

/*
 * Convert the return value of getenv() to an integer using matching stricter
 * than atoi().  If the environment variable is not set, return the default
 * value.  Otherwise return an integer in the interval [0, INT32_MAX] or -1 on
 * error.
 */
static int32_t
strtouint31(const char *str, const int32_t defaultval) {
        if (! str)
                return defaultval;
        if (! str[0])
                return -1;

        char * endp;
        unsigned long val = strtoul(str, &endp, 10);
        if (*endp || val > INT32_MAX)
                return -1;
        return (int32_t)val;
}

static void
delete_pcap_dag(const pcap_t *p)
{
        pcap_dag_node_t *curr = NULL, *prev = NULL;

        for (prev = NULL, curr = pcap_dags; curr != NULL && curr->p != p; prev = curr, curr = curr->next) {
                /* empty */
        }

        if (curr != NULL && curr->p == p) {
                if (prev != NULL) {
                        prev->next = curr->next;
                } else {
                        pcap_dags = curr->next;
                }
        }
}

/*
 * Performs a graceful shutdown of the DAG card, frees dynamic memory held
 * in the pcap_t structure, and closes the file descriptor for the DAG card.
 */

static void
dag_platform_cleanup(pcap_t *p)
{
        struct pcap_dag *pd = p->priv;

        /*
         * Before stopping a Tx stream wait until the stream buffer has been
         * drained, otherwise packets that have been buffered but have not yet
         * been transmitted will be lost.
         */
        if (TX_ONLY(pd->dag_stream))
                while (dag_get_stream_buffer_level64(p->fd, pd->dag_stream) > 0)
                        usleep (10000);

        if(dag_stop_stream(p->fd, pd->dag_stream) < 0)
                fprintf(stderr,"dag_stop_stream: %s\n", strerror(errno));

        if(dag_detach_stream(p->fd, pd->dag_stream) < 0)
                fprintf(stderr,"dag_detach_stream: %s\n", strerror(errno));

        if(pd->dag_ref != NULL) {
                dag_config_dispose(pd->dag_ref);
                /*
                 * Note: we don't need to call close(p->fd) or
                 * dag_close(p->fd), as dag_config_dispose(pd->dag_ref)
                 * does this.
                 *
                 * Set p->fd to -1 to make sure that's not done.
                 */
                p->fd = -1;
                pd->dag_ref = NULL;
        }
        delete_pcap_dag(p);
        pcapint_cleanup_live_common(p);
}

static void
atexit_handler(void)
{
        while (pcap_dags != NULL) {
                if (pcap_dags->pid == getpid()) {
                        if (pcap_dags->p != NULL)
                                dag_platform_cleanup(pcap_dags->p);
                } else {
                        delete_pcap_dag(pcap_dags->p);
                }
        }
}

static int
new_pcap_dag(pcap_t *p)
{
        pcap_dag_node_t *node = NULL;

        if ((node = malloc(sizeof(pcap_dag_node_t))) == NULL) {
                return -1;
        }

        if (!atexit_handler_installed) {
                atexit(atexit_handler);
                atexit_handler_installed = 1;
        }

        node->next = pcap_dags;
        node->p = p;
        node->pid = getpid();

        pcap_dags = node;

        return 0;
}

static unsigned int
dag_erf_ext_header_count(const uint8_t *erf, size_t len)
{
        uint32_t hdr_num = 0;
        uint8_t  hdr_type;

        /* basic sanity checks */
        if ( erf == NULL )
                return 0;
        if ( len < 16 )
                return 0;

        /* check if we have any extension headers */
        if (! (erf[8] & ERF_TYPE_MORE_EXT))
                return 0;

        /* loop over the extension headers */
        do {

                /* sanity check we have enough bytes */
                if ( len < (24 + (hdr_num * 8)) )
                        return hdr_num;

                /* get the header type */
                hdr_type = erf[(16 + (hdr_num * 8))];
                hdr_num++;

        } while (hdr_type & ERF_TYPE_MORE_EXT);

        return hdr_num;
}

static int
dag_rxtx_mismatch(const char *func, pcap_t *p)
{
        const struct pcap_dag *pd = p->priv;

        snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: device %s is %s-only",
            func,
            p->opt.device,
            RXTX_STR(pd->dag_stream));
        return PCAP_ERROR;
}

static int
dag_read_notimpl(pcap_t *p, int cnt _U_, pcap_handler callback _U_, u_char *user _U_)
{
        return dag_rxtx_mismatch(__func__, p);
}

static int
dag_getnonblock_fd_notimpl(pcap_t *p)
{
        return dag_rxtx_mismatch(__func__, p);
}

static int
dag_stats_notimpl(pcap_t *p, struct pcap_stat *ps _U_)
{
        return dag_rxtx_mismatch(__func__, p);
}

static int
dag_setnonblock_notimpl(pcap_t *p, int nonblock _U_)
{
        return dag_rxtx_mismatch( __func__, p);
}

static int
dag_inject_notimpl(pcap_t *p, const void *buf _U_, int size _U_)
{
        return dag_rxtx_mismatch(__func__, p);
}

static int
dag_install_bpf_program_notimpl(pcap_t *p, struct bpf_program *fp _U_)
{
        return dag_rxtx_mismatch(__func__, p);
}

/*
 *  Read at most max_packets from the capture stream and call the callback
 *  for each of them. Returns the number of packets handled, PCAP_ERROR if an
 *  error occurred, or PCAP_ERROR_BREAK if we were told to break out of the loop.
 */
static int
dag_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
{
        struct pcap_dag *pd = p->priv;
        int processed = 0;
        unsigned int nonblocking = pd->dag_flags & DAGF_NONBLOCK;
        unsigned int num_ext_hdr = 0;
        unsigned int ticks_per_second;

        /* Get the next bufferful of packets (if necessary). */
        while (pd->dag_mem_top - pd->dag_mem_bottom < dag_record_size) {

                /*
                 * Has "pcap_breakloop()" been called?
                 */
                if (p->break_loop) {
                        /*
                         * Yes - clear the flag that indicates that
                         * it has, and return PCAP_ERROR_BREAK to indicate that
                         * we were told to break out of the loop.
                         */
                        p->break_loop = 0;
                        return PCAP_ERROR_BREAK;
                }

                /* dag_advance_stream() will block (unless nonblock is called)
                 * until 64kB of data has accumulated.
                 * If to_ms is set, it will timeout before 64kB has accumulated.
                 * We wait for 64kB because processing a few packets at a time
                 * can cause problems at high packet rates (>200kpps) due
                 * to inefficiencies.
                 * This does mean if to_ms is not specified the capture may 'hang'
                 * for long periods if the data rate is extremely slow (<64kB/sec)
                 * If non-block is specified it will return immediately. The user
                 * is then responsible for efficiency.
                 */
                if ( NULL == (pd->dag_mem_top = dag_advance_stream(p->fd, pd->dag_stream, &(pd->dag_mem_bottom))) ) {
                     return PCAP_ERROR;
                }

                if (nonblocking && (pd->dag_mem_top - pd->dag_mem_bottom < dag_record_size))
                {
                        /* Pcap is configured to process only available packets, and there aren't any, return immediately. */
                        return 0;
                }

                if(!nonblocking &&
                   pd->dag_timeout &&
                   (pd->dag_mem_top - pd->dag_mem_bottom < dag_record_size))
                {
                        /* Blocking mode, but timeout set and no data has arrived, return anyway.*/
                        return 0;
                }

        }

        /*
         * Process the packets.
         *
         * This assumes that a single buffer of packets will have
         * <= INT_MAX packets, so the packet count doesn't overflow.
         */
        while (pd->dag_mem_top - pd->dag_mem_bottom >= dag_record_size) {

                unsigned short packet_len = 0;
                int caplen = 0;
                struct pcap_pkthdr      pcap_header;

                dag_record_t *header = (dag_record_t *)(pd->dag_mem_bottom);

                u_char *dp = ((u_char *)header); /* + dag_record_size; */
                unsigned short rlen;

                /*
                 * Has "pcap_breakloop()" been called?
                 */
                if (p->break_loop) {
                        /*
                         * Yes - clear the flag that indicates that
                         * it has, and return PCAP_ERROR_BREAK to indicate that
                         * we were told to break out of the loop.
                         */
                        p->break_loop = 0;
                        return PCAP_ERROR_BREAK;
                }

                rlen = ntohs(header->rlen);
                if (rlen < dag_record_size)
                {
                        snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                            "%s: record too small", __func__);
                        return PCAP_ERROR;
                }
                pd->dag_mem_bottom += rlen;

                uint8_t erf_type = header->type & ERF_TYPE_MASK;

                /* Count lost packets. */
                switch(erf_type) {
                        /* in these types the color value overwrites the lctr */
                case ERF_TYPE_COLOR_HDLC_POS:
                case ERF_TYPE_COLOR_ETH:
                case ERF_TYPE_DSM_COLOR_HDLC_POS:
                case ERF_TYPE_DSM_COLOR_ETH:
                case ERF_TYPE_COLOR_MC_HDLC_POS:
                case ERF_TYPE_COLOR_HASH_ETH:
                case ERF_TYPE_COLOR_HASH_POS:
                        break;

                default:
                        if ( (pd->drop_attr == kNullAttributeUuid) && (header->lctr) ) {
                                pd->stat.ps_drop += ntohs(header->lctr);
                        }
                }

                if (erf_type == ERF_TYPE_PAD) {
                        continue;
                }

                num_ext_hdr = dag_erf_ext_header_count(dp, rlen);

                /* ERF encapsulation */
                /* The Extensible Record Format is not dropped for this kind of encapsulation,
                 * and will be handled as a pseudo header by the decoding application.
                 * The information carried in the ERF header and in the optional subheader (if present)
                 * could be merged with the libpcap information, to offer a better decoding.
                 * The packet length is
                 * o the length of the packet on the link (header->wlen),
                 * o plus the length of the ERF header (dag_record_size), as the length of the
                 *   pseudo header will be adjusted during the decoding,
                 * o plus the length of the optional subheader (if present).
                 *
                 * The capture length is header.rlen and the byte stuffing for alignment will be dropped
                 * if the capture length is greater than the packet length.
                 */
                if (p->linktype == DLT_ERF) {
                        packet_len = ntohs(header->wlen) + dag_record_size;
                        caplen = rlen;
                        switch (erf_type) {
                        case ERF_TYPE_MC_AAL5:
                        case ERF_TYPE_MC_ATM:
                        case ERF_TYPE_MC_HDLC:
                        case ERF_TYPE_MC_RAW_CHANNEL:
                        case ERF_TYPE_MC_RAW:
                        case ERF_TYPE_MC_AAL2:
                        case ERF_TYPE_COLOR_MC_HDLC_POS:
                                packet_len += 4; /* MC header */
                                break;

                        case ERF_TYPE_COLOR_HASH_ETH:
                        case ERF_TYPE_DSM_COLOR_ETH:
                        case ERF_TYPE_COLOR_ETH:
                        case ERF_TYPE_ETH:
                                packet_len += 2; /* ETH header */
                                break;
                        } /* switch type */

                        /* Include ERF extension headers */
                        packet_len += (8 * num_ext_hdr);

                        if (caplen > packet_len) {
                                caplen = packet_len;
                        }
                } else {
                        /* Other kind of encapsulation according to the header Type */

                        /* Skip over generic ERF header */
                        dp += dag_record_size;
                        /* Skip over extension headers */
                        dp += 8 * num_ext_hdr;

                        switch(erf_type) {
                        case ERF_TYPE_ATM:
                        case ERF_TYPE_AAL5:
                                if (erf_type == ERF_TYPE_AAL5) {
                                        packet_len = ntohs(header->wlen);
                                        caplen = rlen - dag_record_size;
                                }
                                /* FALLTHROUGH */
                        case ERF_TYPE_MC_ATM:
                                if (erf_type == ERF_TYPE_MC_ATM) {
                                        caplen = packet_len = ATM_CELL_SIZE;
                                        dp+=4;
                                }
                                /* FALLTHROUGH */
                        case ERF_TYPE_MC_AAL5:
                                if (erf_type == ERF_TYPE_MC_AAL5) {
                                        packet_len = ntohs(header->wlen);
                                        caplen = rlen - dag_record_size - 4;
                                        dp+=4;
                                }
                                /* Skip over extension headers */
                                caplen -= (8 * num_ext_hdr);

                                if (erf_type == ERF_TYPE_ATM) {
                                        caplen = packet_len = ATM_CELL_SIZE;
                                }
                                if (p->linktype == DLT_SUNATM) {
                                        struct sunatm_hdr *sunatm = (struct sunatm_hdr *)dp;
                                        unsigned long rawatm;

                                        rawatm = ntohl(*((uint32_t *)dp));
                                        sunatm->vci = htons((rawatm >>  4) & 0xffff);
                                        sunatm->vpi = (rawatm >> 20) & 0x00ff;
                                        sunatm->flags = ((header->flags.iface & 1) ? 0x80 : 0x00) |
                                                ((sunatm->vpi == 0 && sunatm->vci == htons(5)) ? 6 :
                                                 ((sunatm->vpi == 0 && sunatm->vci == htons(16)) ? 5 :
                                                  ((dp[ATM_HDR_SIZE] == 0xaa &&
                                                    dp[ATM_HDR_SIZE+1] == 0xaa &&
                                                    dp[ATM_HDR_SIZE+2] == 0x03) ? 2 : 1)));

                                } else if (p->linktype == DLT_ATM_RFC1483) {
                                        packet_len -= ATM_HDR_SIZE;
                                        caplen -= ATM_HDR_SIZE;
                                        dp += ATM_HDR_SIZE;
                                } else
                                        continue;
                                break;

                        case ERF_TYPE_COLOR_HASH_ETH:
                        case ERF_TYPE_DSM_COLOR_ETH:
                        case ERF_TYPE_COLOR_ETH:
                        case ERF_TYPE_ETH:
                                if ((p->linktype != DLT_EN10MB) &&
                                    (p->linktype != DLT_DOCSIS))
                                        continue;
                                packet_len = ntohs(header->wlen);
                                packet_len -= (pd->dag_fcs_bits >> 3);
                                caplen = rlen - dag_record_size - 2;
                                /* Skip over extension headers */
                                caplen -= (8 * num_ext_hdr);
                                if (caplen > packet_len) {
                                        caplen = packet_len;
                                }
                                dp += 2;
                                break;

                        case ERF_TYPE_COLOR_HASH_POS:
                        case ERF_TYPE_DSM_COLOR_HDLC_POS:
                        case ERF_TYPE_COLOR_HDLC_POS:
                        case ERF_TYPE_HDLC_POS:
                                if ((p->linktype != DLT_CHDLC) &&
                                    (p->linktype != DLT_PPP_SERIAL) &&
                                    (p->linktype != DLT_FRELAY))
                                        continue;
                                packet_len = ntohs(header->wlen);
                                packet_len -= (pd->dag_fcs_bits >> 3);
                                caplen = rlen - dag_record_size;
                                /* Skip over extension headers */
                                caplen -= (8 * num_ext_hdr);
                                if (caplen > packet_len) {
                                        caplen = packet_len;
                                }
                                break;

                        case ERF_TYPE_COLOR_MC_HDLC_POS:
                        case ERF_TYPE_MC_HDLC:
                                if ((p->linktype != DLT_CHDLC) &&
                                    (p->linktype != DLT_PPP_SERIAL) &&
                                    (p->linktype != DLT_FRELAY) &&
                                    (p->linktype != DLT_MTP2) &&
                                    (p->linktype != DLT_MTP2_WITH_PHDR) &&
                                    (p->linktype != DLT_LAPD))
                                        continue;
                                packet_len = ntohs(header->wlen);
                                packet_len -= (pd->dag_fcs_bits >> 3);
                                caplen = rlen - dag_record_size - 4;
                                /* Skip over extension headers */
                                caplen -= (8 * num_ext_hdr);
                                if (caplen > packet_len) {
                                        caplen = packet_len;
                                }
                                /* jump the MC_HDLC_HEADER */
                                dp += 4;
                                if (p->linktype == DLT_MTP2_WITH_PHDR) {
                                        /* Add the MTP2 Pseudo Header */
                                        caplen += MTP2_HDR_LEN;
                                        packet_len += MTP2_HDR_LEN;

                                        TempPkt[MTP2_SENT_OFFSET] = 0;
                                        TempPkt[MTP2_ANNEX_A_USED_OFFSET] = MTP2_ANNEX_A_USED_UNKNOWN;
                                        *(TempPkt+MTP2_LINK_NUMBER_OFFSET) = ((header->rec.mc_hdlc.mc_header>>16)&0x01);
                                        *(TempPkt+MTP2_LINK_NUMBER_OFFSET+1) = ((header->rec.mc_hdlc.mc_header>>24)&0xff);
                                        memcpy(TempPkt+MTP2_HDR_LEN, dp, caplen);
                                        dp = TempPkt;
                                }
                                break;

                        case ERF_TYPE_IPV4:
                                if ((p->linktype != DLT_RAW) &&
                                    (p->linktype != DLT_IPV4))
                                        continue;
                                packet_len = ntohs(header->wlen);
                                caplen = rlen - dag_record_size;
                                /* Skip over extension headers */
                                caplen -= (8 * num_ext_hdr);
                                if (caplen > packet_len) {
                                        caplen = packet_len;
                                }
                                break;

                        case ERF_TYPE_IPV6:
                                if ((p->linktype != DLT_RAW) &&
                                    (p->linktype != DLT_IPV6))
                                        continue;
                                packet_len = ntohs(header->wlen);
                                caplen = rlen - dag_record_size;
                                /* Skip over extension headers */
                                caplen -= (8 * num_ext_hdr);
                                if (caplen > packet_len) {
                                        caplen = packet_len;
                                }
                                break;

                        /* These types have no matching 'native' DLT, but can be used with DLT_ERF above */
                        case ERF_TYPE_MC_RAW:
                        case ERF_TYPE_MC_RAW_CHANNEL:
                        case ERF_TYPE_IP_COUNTER:
                        case ERF_TYPE_TCP_FLOW_COUNTER:
                        case ERF_TYPE_INFINIBAND:
                        case ERF_TYPE_RAW_LINK:
                        case ERF_TYPE_INFINIBAND_LINK:
                        default:
                                /* Unhandled ERF type.
                                 * Ignore rather than generating error
                                 */
                                continue;
                        } /* switch type */

                } /* ERF encapsulation */

                /*
                 * In this libpcap module the two length arguments of
                 * pcapint_filter() (the wire length and the captured length)
                 * can have different values.
                 *
                 * The wire length of this packet is packet_len, which is
                 * derived from ERF wlen; the captured length of this packet
                 * is caplen, which is derived from ERF rlen, which in turn
                 * depends on the card/stream slen; the snapshot length
                 * configured for this pcap handle is p->snapshot.
                 */
                if ((p->fcode.bf_insns == NULL) || pcapint_filter(p->fcode.bf_insns, dp, packet_len, caplen)) {

                        /* convert between timestamp formats */
                        register unsigned long long ts;

#if __BYTE_ORDER == __BIG_ENDIAN
                        ts = SWAPLL(header->ts);
#else
                        ts = header->ts;
#endif // __BYTE_ORDER

                        switch (p->opt.tstamp_precision) {
                        case PCAP_TSTAMP_PRECISION_NANO:
                                ticks_per_second = 1000000000;
                                break;
                        case PCAP_TSTAMP_PRECISION_MICRO:
                        default:
                                ticks_per_second = 1000000;
                                break;

                        }
                        pcap_header.ts.tv_sec = ts >> 32;
                        ts = (ts & 0xffffffffULL) * ticks_per_second;
                        ts += 0x80000000; /* rounding */
                        pcap_header.ts.tv_usec = ts >> 32;
                        if (pcap_header.ts.tv_usec >= ticks_per_second) {
                                pcap_header.ts.tv_usec -= ticks_per_second;
                                pcap_header.ts.tv_sec++;
                        }

                        /* Fill in our own header data */
                        pcap_header.caplen = min(caplen, p->snapshot);
                        pcap_header.len = packet_len;

                        /* Count the packet. */
                        pd->stat.ps_recv++;

                        /* Call the user supplied callback function */
                        callback(user, &pcap_header, dp);

                        /* Only count packets that pass the filter, for consistency with standard Linux behaviour. */
                        processed++;
                        if (processed == cnt && !PACKET_COUNT_IS_UNLIMITED(cnt))
                        {
                                /* Reached the user-specified limit. */
                                return cnt;
                        }
                }
        }

        return processed;
}

/*
 * The minimum number of bytes in a valid Ethernet packet from the beginning
 * of the destination MAC address to the end of the payload, as far as DAG
 * TERF and IEEE 802.3 are concerned.
 */
#define ETH_MINLEN_NOFCS 60

// ...and the maximum, as far as DAG TERF is concerned.
#define ETH_MAXLEN_NOFCS 9596

/*
 * The minimum number of bytes in a valid Ethernet header: the destination and
 * the source MAC addresses, the EtherType.  (This does not take 802.1Q or
 * Q-in-Q into account.)
 */
#define ETH_MINLEN_HDRONLY 14

// Zero padding source (a bit oversized for ERF_TYPE_ETH purposes).
static const uint8_t tx_pad[ETH_MINLEN_NOFCS + 4 + ALIGN_BYTES_MAX];

/*
 * Take an Ethernet frame, build an ERF record around it and feed the record
 * into the [Tx-only] DAG stream.  The frame must not include FCS, which is
 * usually the case for DLT_EN10MB in libpcap.
 */
static int
dag_inject(pcap_t *p, const void *packet, const int plen)
{
        struct pcap_dag *pd = p->priv;

        if (plen <= ETH_MINLEN_HDRONLY || plen > ETH_MAXLEN_NOFCS) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "invalid packet size %d", plen);
                return PCAP_ERROR;
        }

        /*
         * sizeof(struct dag_record_t) cannot be used because it is much
         * greater than the specific ERF header in this buffer.
         */
        const dag_size_t hlen = dag_record_size + 2;
        /*
         * Some DAG hardware (e.g. 7.5G2) automatically pads outgoing Ethernet
         * frames that are shorter than the minimum length to make them long
         * enough.  Other DAG hardware (e.g. 9.2X2) rejects such frames.  Pad
         * the frame here if necessary and remove this difference from the
         * problem space.
         *
         * If the TERF is expecting Ethernet frames to have a non-zero number
         * of FCS bytes (typically in order to strip the FCS correctly before
         * further processing), append a dummy zero FCS of the expected size.
         */
        const unsigned eth_pad_len = ETH_MINLEN_NOFCS
            - min(plen, ETH_MINLEN_NOFCS) + pd->terf_fcs_bytes;
        const unsigned rlen = hlen + plen + eth_pad_len;
        const unsigned erf_pad_len = rlen % pd->tx_align_bytes ?
            pd->tx_align_bytes - rlen % pd->tx_align_bytes :
            0;
        dag_record_t header = {
                .type = ERF_TYPE_ETH,
                .flags.vlen = 1,
                .rlen = htons(rlen + erf_pad_len),
                .wlen = htons(plen + eth_pad_len),
                // Silence a -Wmissing-field-initializers from old GCC.
                .rec.eth = {0},
        };
        DAG_ERF_SET_IFACE(&header, pd->tx_iface);

        /*
         * It is fine to feed less data than a complete ERF record at a time so
         * long as a complete and well-formed ERF record eventually makes it
         * into the buffer.  This simplifies the process when different parts
         * of the ERF record come from different memory locations.
         */
        if (dag_tx_stream_copy_bytes64(p->fd, pd->dag_stream, (uint8_t *)&header, hlen) < 0 ||
            dag_tx_stream_copy_bytes64(p->fd, pd->dag_stream, (uint8_t *)packet, plen) < 0)
                goto fail;
        /*
         * Possibly pad to the minimum packet length and/or append a dummy FCS
         * and/or pad to the next multiple of the detected alignment unit.
         */
        const unsigned pad_len = eth_pad_len + erf_pad_len;
        if (pad_len &&
            dag_tx_stream_copy_bytes64(p->fd, pd->dag_stream, (uint8_t *)tx_pad, pad_len) < 0)
                goto fail;
        return plen;

fail:
        pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
            errno, "dag_tx_stream_copy_bytes64 %s", p->opt.device);
        return PCAP_ERROR;
}

static int
dag_activate_tx(pcap_t *p)
{
        struct pcap_dag *pd = p->priv;

        const char * env = getenv(ENV_TX_IFACE);
        int32_t iface = strtouint31(env, 0);
        if (iface < 0) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "%s: failed parsing %s value \"%s\"",
                    __func__, ENV_TX_IFACE, env);
                return PCAP_ERROR;
        }
        uint32_t ifcount = dag_config_get_interface_count(pd->dag_ref);
        if ((uint32_t)iface >= ifcount) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "%s: invalid %s value %u: this card has %u interface(s)",
                    __func__, ENV_TX_IFACE, iface, ifcount);
                return PCAP_ERROR;
        }
        pd->tx_iface = (uint8_t)iface;

        const dag_card_inf_t *inf = dag_pciinfo(p->fd);
        if (! inf) {
                pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                    errno, "dag_pciinfo");
                return PCAP_ERROR;
        }

        if (inf->device_code == PCI_DEVICE_ID_VDAG) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "vDAG Tx streams are not supported");
                return PCAP_ERROR;
        }

        // Determine the correct alignment/padding size for the card.
        switch(inf->device_code) {
        case PCI_DEVICE_ID_DAG9_2X2:
        case PCI_DEVICE_ID_DAG9_2SX2:
                pd->tx_align_bytes = ALIGN_BYTES_9_2;
                break;
        default:
                pd->tx_align_bytes = ALIGN_BYTES_DEFAULT;
        }

        // Read the TERF FCS size for later use by dag_inject().
        dag_component_t cfg_comp = dag_component_get_subcomponent(
            pd->dag_root, kComponentTerf, 0);
        if (! cfg_comp) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "%s: dag_component_get_subcomponent",
                    __func__);
                return PCAP_ERROR;
        }

        attr_uuid_t cfg_uuid = dag_component_get_config_attribute_uuid(
            cfg_comp, kUint32AttributeTerfStripCrc);
        if (cfg_uuid == kNullAttributeUuid) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "%s: dag_component_get_config_attribute_uuid",
                    __func__);
                return PCAP_ERROR;
        }

        uint32_t cfg_uint32;
        dag_err_t cfg_err = dag_config_get_uint32_attribute_ex(pd->dag_ref,
            cfg_uuid, &cfg_uint32);
        if (cfg_err != kDagErrNone) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "%s: dag_config_get_uint32_attribute_ex",
                    __func__);
                return PCAP_ERROR;
        }

        switch (cfg_uint32) {
        case kTerfNoStrip:
                pd->terf_fcs_bytes = 0;
                break;
        case kTerfStrip16:
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "TERF FCS is configured to 16 bits, is this Ethernet?");
                return PCAP_ERROR;
        case kTerfStrip32:
                pd->terf_fcs_bytes = 4;
                break;
        default:
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "failed reading TERF FCS configuration");
                return PCAP_ERROR;
        }

        /*
         * TODO: It would be nice to verify that the Tx port is
         * configured for 32-bit Tx FCS, but it is not trivial to
         * tell the exact subcomponent that has the attribute.
         */

        return 0;
}

/*
 *  Get a handle for a live capture from the given DAG device.  The promisc
 *  flag is ignored because DAG cards are always promiscuous.  The to_ms
 *  parameter is used in setting the API polling parameters.
 *
 *  See also pcap(3).
 */
static int dag_activate(pcap_t* p)
{
        struct pcap_dag *pd = p->priv;
        char *s;
        int n;
        char * device = p->opt.device;
        int ret;
        dag_size_t mindata;
        struct timeval maxwait;
        struct timeval poll;

        /*
         * dag_create() has validated the device name syntax and stored the
         * parsed device and stream numbers to p->priv.  Validate these values
         * semantically.
         */
        if (pd->dag_devnum >= DAG_MAX_BOARDS) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "DAG device number %d is too large", pd->dag_devnum);
                ret = PCAP_ERROR_NO_SUCH_DEVICE;
                goto fail;
        }
        if (pd->dag_stream >= DAG_STREAM_MAX) {
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "DAG stream number %d is too large", pd->dag_stream);
                ret = PCAP_ERROR_NO_SUCH_DEVICE;
                goto fail;
        }
#ifndef ENABLE_DAG_TX
        if (TX_ONLY(pd->dag_stream)) {
                /*
                 * dag_findalldevs() does not return any Tx streams, so
                 * PCAP_ERROR_NO_SUCH_DEVICE is more consistent than
                 * PCAP_ERROR_CAPTURE_NOTSUP.
                 */
                ret = PCAP_ERROR_NO_SUCH_DEVICE;
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: tx (odd numbered) streams not supported for capture", __func__);
                goto fail;
        }
#endif // ENABLE_DAG_TX

        /* setup device parameters */
        if((pd->dag_ref = dag_config_init(device)) == NULL) {
                /*
                 * XXX - does this reliably set errno?
                 */
                if (errno == ENOENT) {
                        /*
                         * There's nothing more to say, so clear
                         * the error message.
                         */
                        ret = PCAP_ERROR_NO_SUCH_DEVICE;
                        p->errbuf[0] = '\0';
                } else if (errno == EPERM || errno == EACCES) {
                        ret = PCAP_ERROR_PERM_DENIED;
                        snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                            "Attempt to open %s failed with %s - additional privileges may be required",
                            device, (errno == EPERM) ? "EPERM" : "EACCES");
                } else {
                        ret = PCAP_ERROR;
                        pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                            errno, "dag_config_init %s", device);
                }
                goto fail;
        }

        if((p->fd = dag_config_get_card_fd(pd->dag_ref)) < 0) {
                /*
                 * XXX - does this reliably set errno?
                 */
                ret = PCAP_ERROR;
                pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                    errno, "dag_config_get_card_fd %s", device);
                goto failclose;
        }

        /* Open requested stream. Can fail if already locked or on error */
        if (dag_attach_stream64(p->fd, pd->dag_stream, 0, 0) < 0) {
                if (errno == ENOMEM) {
                        snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                            "dag%u has no memory allocated to %s stream %u",
                            pd->dag_devnum, RXTX_STR(pd->dag_stream), pd->dag_stream);
                        /*
                         * dag_findalldevs() does not return streams that do
                         * not have buffer memory, so PCAP_ERROR_NO_SUCH_DEVICE
                         * is more consistent than PCAP_ERROR_CAPTURE_NOTSUP.
                         */
                        ret = PCAP_ERROR_NO_SUCH_DEVICE;
                        goto failclose;
                } else if (errno == EINVAL) {
                        snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                            "dag%u has no %s stream %u",
                            pd->dag_devnum, RXTX_STR(pd->dag_stream), pd->dag_stream);
                        ret = PCAP_ERROR_NO_SUCH_DEVICE;
                        goto failclose;
                }
                ret = PCAP_ERROR;
                pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                    errno, "dag_attach_stream64");
                goto failclose;
        }

        /* Try to find Stream Drop attribute */
        pd->drop_attr = kNullAttributeUuid;
        pd->dag_root = dag_config_get_root_component(pd->dag_ref);
        if ( dag_component_get_subcomponent(pd->dag_root, kComponentStreamFeatures, 0) )
        {
                pd->drop_attr = dag_config_get_indexed_attribute_uuid(pd->dag_ref, kUint32AttributeStreamDropCount, pd->dag_stream);
                if (pd->drop_attr != kNullAttributeUuid)
                        pd->drop_base = dag_config_get_uint64_attribute(
                            pd->dag_ref, pd->drop_attr);
        }

        /* Set up default poll parameters for stream
         * Can be overridden by pcap_set_nonblock()
         */
        if (dag_get_stream_poll64(p->fd, pd->dag_stream,
                                &mindata, &maxwait, &poll) < 0) {
                ret = PCAP_ERROR;
                pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                    errno, "dag_get_stream_poll64");
                goto faildetach;
        }

        /* Use the poll time as the required select timeout for callers
         * who are using select()/etc. in an event loop waiting for
         * packets to arrive.
         */
        pd->required_select_timeout = poll;
        p->required_select_timeout = &pd->required_select_timeout;

        /*
         * 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->opt.immediate) {
                /* Call callback immediately.
                 * XXX - is this the right way to p this?
                 */
                mindata = 0;
        } else {
                /* Amount of data to collect in Bytes before calling callbacks.
                 * Important for efficiency, but can introduce latency
                 * at low packet rates if to_ms not set!
                 */
                mindata = 65536;
        }

        /* Obey opt.timeout (was to_ms) if supplied. This is a good idea!
         * Recommend 10-100ms. Calls will time out even if no data arrived.
         */
        maxwait.tv_sec = p->opt.timeout/1000;
        maxwait.tv_usec = (p->opt.timeout%1000) * 1000;

        if (dag_set_stream_poll64(p->fd, pd->dag_stream,
                                mindata, &maxwait, &poll) < 0) {
                ret = PCAP_ERROR;
                pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                    errno, "dag_set_stream_poll64");
                goto faildetach;
        }

        if(dag_start_stream(p->fd, pd->dag_stream) < 0) {
                ret = PCAP_ERROR;
                pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                    errno, "dag_start_stream %s", device);
                goto faildetach;
        }

        /*
         * Important! You have to ensure bottom is properly
         * initialized to zero on startup, it won't give you
         * a compiler warning if you make this mistake!
         */
        pd->dag_mem_bottom = 0;
        pd->dag_mem_top = 0;

        /*
         * Find out how many FCS bits we should strip.
         * Assume Rx FCS length to be 32 bits unless the user has
         * requested a different value, in which case validate it well.
         */
        s = getenv(ENV_RX_FCS_BITS);
        switch ((n = strtouint31(s, 32))) {
        case 0:
        case 16:
        case 32:
                pd->dag_fcs_bits = n;
                break;
        default:
                ret = PCAP_ERROR;
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "%s %s: invalid %s value (%s) in environment",
                    __func__, device, ENV_RX_FCS_BITS, s);
                goto failstop;
        }

        /*
         * Did the user request that they not be stripped?
         */
        s = getenv(ENV_RX_FCS_NOSTRIP);
        switch ((n = strtouint31(s, 0))) {
        case 0:
                break;
        case 1:
                /* Yes.  Note the number of 16-bit words that will be
                   supplied. */
                p->linktype_ext = LT_FCS_DATALINK_EXT(pd->dag_fcs_bits/16);

                /* And don't strip them. */
                pd->dag_fcs_bits = 0;
                break;
        default:
                ret = PCAP_ERROR;
                snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
                    "%s %s: invalid %s value (%s) in environment",
                    __func__, device, ENV_RX_FCS_NOSTRIP, s);
                goto failstop;
        }

        if (TX_ONLY(pd->dag_stream) && dag_activate_tx(p) < 0) {
                ret = PCAP_ERROR;
                goto failstop;
        }

        pd->dag_timeout = p->opt.timeout;

        if (dag_get_datalink(p) < 0) {
                ret = PCAP_ERROR;
                goto failstop;
        }

        p->bufsize = 0;

        if (new_pcap_dag(p) < 0) {
                ret = PCAP_ERROR;
                pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                    errno, "new_pcap_dag %s", device);
                goto failstop;
        }

        /*
         * "select()" and "poll()" don't work on DAG device descriptors.
         */
        p->selectable_fd = -1;

        p->read_op = RX_ONLY(pd->dag_stream) ?
            dag_read :
            dag_read_notimpl;
        p->inject_op = TX_ONLY(pd->dag_stream) ?
            dag_inject :
            dag_inject_notimpl;
        p->setfilter_op = RX_ONLY(pd->dag_stream) ?
            pcapint_install_bpf_program :
            dag_install_bpf_program_notimpl;
        p->setdirection_op = NULL; /* Not implemented.*/
        p->set_datalink_op = dag_set_datalink;
        p->getnonblock_op = RX_ONLY(pd->dag_stream) ?
            pcapint_getnonblock_fd :
            dag_getnonblock_fd_notimpl;
        p->setnonblock_op = RX_ONLY(pd->dag_stream) ?
            dag_setnonblock :
            dag_setnonblock_notimpl;
        p->stats_op = RX_ONLY(pd->dag_stream) ?
            dag_stats :
            dag_stats_notimpl;
        p->cleanup_op = dag_platform_cleanup;
        pd->stat.ps_drop = 0;
        pd->stat.ps_recv = 0;
        pd->stat.ps_ifdrop = 0;
        return 0;

failstop:
        if (dag_stop_stream(p->fd, pd->dag_stream) < 0) {
                fprintf(stderr,"dag_stop_stream: %s\n", strerror(errno));
        }

faildetach:
        if (dag_detach_stream(p->fd, pd->dag_stream) < 0)
                fprintf(stderr,"dag_detach_stream: %s\n", strerror(errno));

failclose:
        dag_config_dispose(pd->dag_ref);
        /*
         * Note: we don't need to call close(p->fd) or dag_close(p->fd),
         * as dag_config_dispose(pd->dag_ref) does this.
         *
         * Set p->fd to -1 to make sure that's not done.
         */
        p->fd = -1;
        pd->dag_ref = NULL;
        delete_pcap_dag(p);

fail:
        pcapint_cleanup_live_common(p);

        return ret;
}

pcap_t *dag_create(const char *device, char *ebuf, int *is_ours)
{
        const char *cp;
        char *cpend;
        long devnum;
        pcap_t *p;
        long stream = 0;

        /*
         * The nominal libpcap DAG device name format is either "dagN" or
         * "dagN:M", as returned from dag_findalldevs().
         *
         * First attempt the most basic syntax validation.  If the device string
         * does not look like a potentially valid DAG device name, reject it
         * silently to have pcap_create() try another capture source type.
         */
        *is_ours = 0;

        /* Does this look like a DAG device? */
        cp = device;
        /* Does it begin with "dag"? */
        if (strncmp(cp, "dag", 3) != 0) {
                /* Nope, doesn't begin with "dag" */
                return NULL;
        }
        /* Yes - is "dag" followed by a number from 0 to DAG_MAX_BOARDS-1 */
        cp += 3;
        devnum = strtol(cp, &cpend, 10);
        if (*cpend == ':') {
                /* Followed by a stream number. */
                stream = strtol(++cpend, &cpend, 10);
        }

        if (cpend == cp || *cpend != '\0') {
                /* Not followed by a number. */
                return NULL;
        }

        /*
         * OK, it's probably ours, validate the syntax further.  From now on
         * reject the device string authoritatively with an error message to
         * have pcap_create() propagate the failure.  Validate the device and
         * stream number ranges loosely only.
         */
        *is_ours = 1;
        snprintf (ebuf, PCAP_ERRBUF_SIZE,
            "DAG device name \"%s\" is invalid", device);

        if (devnum < 0 || devnum > INT_MAX) {
                /* Followed by a non-valid number. */
                return NULL;
        }

        if (stream < 0 || stream > INT_MAX) {
                /* Followed by a non-valid stream number. */
                return NULL;
        }

        /*
         * The syntax validation done so far is lax enough to accept some
         * device strings that are not actually acceptable in libpcap as
         * defined above.  The device strings that are acceptable in libpcap
         * are a strict subset of the device strings that are acceptable in
         * dag_parse_name(), thus using the latter for validation in libpcap
         * would not work reliably.  Instead from the detected device and
         * stream numbers produce the acceptable device string(s) and require
         * the input device string to match an acceptable string exactly.
         */
        char buf[DAGNAME_BUFSIZE];
        snprintf(buf, sizeof(buf), "dag%ld:%ld", devnum, stream);
        char acceptable = ! strcmp(device, buf);
        if (! acceptable && stream == 0) {
                snprintf(buf, sizeof(buf), "dag%ld", devnum);
                acceptable = ! strcmp(device, buf);
        }
        if (! acceptable)
                return NULL;

        /*
         * The device string syntax is acceptable, save the device and stream
         * numbers for dag_activate(), which will do semantic and run-time
         * validation and possibly reject the pcap_t using more specific error
         * codes.
         */
        ebuf[0] = '\0';
        p = PCAP_CREATE_COMMON(ebuf, struct pcap_dag);
        if (p == NULL)
                return NULL;

        p->activate_op = dag_activate;

        /*
         * We claim that we support microsecond and nanosecond time
         * stamps.
         *
         * XXX Our native precision is 2^-32s, but libpcap doesn't support
         * power of two precisions yet. We can convert to either MICRO or NANO.
         */
        p->tstamp_precision_list = malloc(2 * sizeof(u_int));
        if (p->tstamp_precision_list == NULL) {
                pcapint_fmt_errmsg_for_errno(ebuf, PCAP_ERRBUF_SIZE,
                    errno, "malloc");
                pcap_close(p);
                return NULL;
        }
        p->tstamp_precision_list[0] = PCAP_TSTAMP_PRECISION_MICRO;
        p->tstamp_precision_list[1] = PCAP_TSTAMP_PRECISION_NANO;
        p->tstamp_precision_count = 2;
        struct pcap_dag *pd = p->priv;
        pd->dag_devnum = (int)devnum;
        pd->dag_stream = (int)stream;
        return p;
}

static int
dag_stats(pcap_t *p, struct pcap_stat *ps) {
        struct pcap_dag *pd = p->priv;
        uint64_t stream_drop;
        dag_err_t dag_error;

        /*
         * Packet records received (ps_recv) are counted in dag_read().
         * Packet records dropped (ps_drop) are read from Stream Drop attribute if present,
         * otherwise integrate the ERF Header lctr counts (if available) in dag_read().
         * We are reporting that no records are dropped by the card/driver (ps_ifdrop).
         */

        if(pd->drop_attr != kNullAttributeUuid) {
                /* Note this counter is cleared at start of capture and will wrap at UINT_MAX.
                 * The application is responsible for polling ps_drop frequently enough
                 * to detect each wrap and integrate total drop with a wider counter */
                if ((dag_error = dag_config_get_uint64_attribute_ex(pd->dag_ref, pd->drop_attr, &stream_drop)) == kDagErrNone) {
                        pd->stat.ps_drop = (u_int)(stream_drop - pd->drop_base);
                } else {
                        snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "reading stream drop attribute: %s",
                                 dag_config_strerror(dag_error));
                        return PCAP_ERROR;
                }
        }

        *ps = pd->stat;

        return 0;
}

static const char *
dag_device_description(const unsigned dagid)
{
        static char buf[128];
        snprintf(buf, sizeof(buf), "alias for dag%u:0", dagid);
        return buf;
}

static const char *
dag_stream_short_description(const unsigned stream)
{
        static char buf[128];
        snprintf(buf, sizeof(buf), "%s stream %u", RXTX_STR(stream), stream);
        return buf;
}

static const char *
dag_stream_long_description(const unsigned stream, const dag_size_t bufsize,
    const dag_card_inf_t * inf)
{
        static char buf[256];
        int done = snprintf(buf, sizeof(buf),
            "%s stream %u, %" PRIu64 " MiB, %s",
            RXTX_STR(stream),
            stream,
            bufsize / 1024 / 1024,
            inf ? dag_device_name(inf->device_code, 1) : "N/A");
        if (inf->device_code != PCI_DEVICE_ID_VDAG)
                snprintf(buf + done, sizeof(buf) - done,
                    " rev %c at %s",
                    (inf && inf->brd_rev < 26) ? ('A' + inf->brd_rev) : '?',
                    inf ? inf->bus_id : "N/A");
        return buf;
}

/*
 * Add all DAG devices.
 */
int
dag_findalldevs(pcap_if_list_t *devlistp, char *errbuf)
{
        int c;
        int dagfd;
        const char * description;
        int stream, rxstreams;
        // A DAG card associates a link status with each physical port, but not
        // with the data streams.  The number of ports is a matter of hardware,
        // the number of streams and how each stream associates with zero or
        // more ports is a matter of how the user configures the card.  In this
        // context libpcap uses the streams only (i.e. "dag0" is a shorthand
        // for "dag0:0"), thus the notion of link status does not apply to the
        // resulting libpcap DAG capture devices.
        const bpf_u_int32 flags = PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
        FILE * sysfsinfo = NULL;

        /* Try all the DAGs 0-DAG_MAX_BOARDS */
        for (c = 0; c < DAG_MAX_BOARDS; c++) {
                char name[DAGNAME_BUFSIZE]; // libpcap device
                snprintf(name, sizeof(name), "dag%d", c);
                char dagname[DAGNAME_BUFSIZE]; // DAG API device
                snprintf(dagname, sizeof(dagname), "/dev/dag%d", c);
                if ( (dagfd = dag_open(dagname)) >= 0 ) {
                        // Do not add a shorthand device for stream 0 (dagN) yet -- the
                        // user can disable any stream in the card configuration.
                        const dag_card_inf_t * inf = dag_pciinfo(dagfd); // NULL is fine
                        // The count includes existing streams that have no buffer memory.
                        rxstreams = dag_rx_get_stream_count(dagfd);
                        if (rxstreams < 0) {
                                pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
                                    errno, "dag_rx_get_stream_count");
                                goto failclose;
                        }
                        int txstreams = 0;
#ifdef ENABLE_DAG_TX
                        txstreams = dag_tx_get_stream_count(dagfd);
                        if (txstreams < 0) {
                                pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
                                    errno, "dag_tx_get_stream_count");
                                goto failclose;
                        }
#endif // ENABLE_DAG_TX
                        for(stream = 0;
                            stream < DAG_STREAM_MAX && (rxstreams > 0 || txstreams > 0);
                            stream++) {
#ifndef ENABLE_DAG_TX
                                if (TX_ONLY(stream))
                                        continue;
#endif // ENABLE_DAG_TX
                                /*
                                 * dag_attach_stream64() was used before to test if the
                                 * stream exists, but it is not the best tool for the
                                 * job because it tries to lock the stream exclusively.
                                 * If the stream is already locked by another process,
                                 * it fails with EBUSY, otherwise it creates a race
                                 * condition for other processes that may be trying to
                                 * lock the same stream at the same time.  Therefore
                                 * dag_get_stream_buffer_size64() seems to be a better
                                 * fit.
                                 */
                                dag_ssize_t bufsize = dag_get_stream_buffer_size64(dagfd, stream);
                                if (bufsize < 0)
                                        continue; // Does not exist.
                                // Only streams with buffer memory are usable.
                                if (bufsize > 0 &&
                                    (RX_ONLY(stream) || inf->device_code != PCI_DEVICE_ID_VDAG)) {
                                        description = dag_device_description (c);
                                        // a conditional shorthand device
                                        if (stream == 0 &&
                                            pcapint_add_dev(devlistp, name, flags, description, errbuf) == NULL)
                                                goto failclose;
                                        // and the stream device
                                        snprintf(name,  sizeof(name), "dag%d:%d", c, stream);
                                        description = dag_stream_long_description(stream,
                                            dag_get_stream_buffer_size64(dagfd, stream), inf);
                                        if (pcapint_add_dev(devlistp, name, flags, description, errbuf) == NULL) {
                                                goto failclose;
                                        }
                                }
                                if (RX_ONLY(stream))
                                        rxstreams--;
                                else
                                        txstreams--;
                        }
                        dag_close(dagfd);
                        dagfd = -1;
                } else if (errno == EACCES) {
                        // The device exists, but the current user privileges are not
                        // sufficient for dag_open().
                        // Do not add a shorthand device for stream 0 yet -- same as above.
                        // Try enumerating the streams using sysfs.  The file lists
                        // all streams (Rx and Tx) that have non-zero amount of buffer
                        // memory.
                        char sysfspath[PATH_MAX];
                        snprintf(sysfspath, sizeof(sysfspath), "/sys/devices/virtual/dag/%s/info", name);
                        if ((sysfsinfo = fopen(sysfspath, "r"))) {
                                char linebuf[1024];
                                while (fgets(linebuf, sizeof(linebuf), sysfsinfo))
                                        if (1 == sscanf(linebuf, "Stream %u:", &stream)) {
#ifndef ENABLE_DAG_TX
                                                if (TX_ONLY(stream))
                                                        continue;
#endif // ENABLE_DAG_TX
                                                // a conditional shorthand device
                                                description = dag_device_description(c);
                                                if (stream == 0 &&
                                                    pcapint_add_dev(devlistp, name, flags, description, errbuf) == NULL)
                                                        goto failclose;
                                                // and the stream device
                                                snprintf(name,  sizeof(name), "dag%u:%u", c, stream);
                                                // TODO: Parse and describe the buffer size too.
                                                description = dag_stream_short_description(stream);
                                                if (pcapint_add_dev(devlistp, name, flags, description, errbuf) == NULL)
                                                        goto failclose;
                                        }
                                fclose(sysfsinfo);
                                sysfsinfo = NULL;
                        }
                } // errno == EACCES

        }
        return (0);

failclose:
        if (dagfd >= 0)
                dag_close(dagfd);
        if (sysfsinfo)
                fclose(sysfsinfo);
        return PCAP_ERROR;
}

static int
dag_set_datalink(pcap_t *p, int dlt)
{
        p->linktype = dlt;

        return (0);
}

static int
dag_setnonblock(pcap_t *p, int nonblock)
{
        struct pcap_dag *pd = p->priv;
        dag_size_t mindata;
        struct timeval maxwait;
        struct timeval poll;

        /*
         * Set non-blocking mode on the FD.
         * XXX - is that necessary?  If not, don't bother calling it,
         * and have a "dag_getnonblock()" function that looks at
         * "pd->dag_flags".
         */
        if (pcapint_setnonblock_fd(p, nonblock) < 0)
                return PCAP_ERROR;

        if (dag_get_stream_poll64(p->fd, pd->dag_stream,
                                &mindata, &maxwait, &poll) < 0) {
                pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                    errno, "dag_get_stream_poll64");
                return PCAP_ERROR;
        }

        /* Amount of data to collect in Bytes before calling callbacks.
         * Important for efficiency, but can introduce latency
         * at low packet rates if to_ms not set!
         */
        if(nonblock)
                mindata = 0;
        else
                mindata = 65536;

        if (dag_set_stream_poll64(p->fd, pd->dag_stream,
                                mindata, &maxwait, &poll) < 0) {
                pcapint_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
                    errno, "dag_set_stream_poll64");
                return PCAP_ERROR;
        }

        if (nonblock) {
                pd->dag_flags |= DAGF_NONBLOCK;
        } else {
                pd->dag_flags &= ~DAGF_NONBLOCK;
        }
        return (0);
}

static int
dag_get_datalink(pcap_t *p)
{
        struct pcap_dag *pd = p->priv;

        /*
         * There seems to be no trivial way to tell which ERF type(s) a Tx
         * stream would accept.  Let's assume ERF_TYPE_ETH would work, which
         * in libpcap terms means using DLT_EN10MB.
         */
        if (TX_ONLY(pd->dag_stream))
                return (p->linktype = DLT_EN10MB);

        int index=0, dlt_index=0;
        uint8_t types[255];

        memset(types, 0, 255);

        if (p->dlt_list == NULL && (p->dlt_list = malloc(255*sizeof(*(p->dlt_list)))) == NULL) {
                pcapint_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
                    errno, "malloc");
                return PCAP_ERROR;
        }

        p->linktype = 0;

        /* Get list of possible ERF types for this card */
        if (dag_get_stream_erf_types(p->fd, pd->dag_stream, types, 255) < 0) {
                pcapint_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
                    errno, "dag_get_stream_erf_types");
                return PCAP_ERROR;
        }

        while (types[index]) {

                switch((types[index] & ERF_TYPE_MASK)) {

                case ERF_TYPE_HDLC_POS:
                case ERF_TYPE_COLOR_HDLC_POS:
                case ERF_TYPE_DSM_COLOR_HDLC_POS:
                case ERF_TYPE_COLOR_HASH_POS:
                        p->dlt_list[dlt_index++] = DLT_CHDLC;
                        p->dlt_list[dlt_index++] = DLT_PPP_SERIAL;
                        p->dlt_list[dlt_index++] = DLT_FRELAY;
                        if(!p->linktype)
                                p->linktype = DLT_CHDLC;
                        break;

                case ERF_TYPE_ETH:
                case ERF_TYPE_COLOR_ETH:
                case ERF_TYPE_DSM_COLOR_ETH:
                case ERF_TYPE_COLOR_HASH_ETH:
                        /*
                         * 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[dlt_index++] = DLT_EN10MB;
                        p->dlt_list[dlt_index++] = DLT_DOCSIS;
                        if(!p->linktype)
                                p->linktype = DLT_EN10MB;
                        break;

                case ERF_TYPE_ATM:
                case ERF_TYPE_AAL5:
                case ERF_TYPE_MC_ATM:
                case ERF_TYPE_MC_AAL5:
                        p->dlt_list[dlt_index++] = DLT_ATM_RFC1483;
                        p->dlt_list[dlt_index++] = DLT_SUNATM;
                        if(!p->linktype)
                                p->linktype = DLT_ATM_RFC1483;
                        break;

                case ERF_TYPE_COLOR_MC_HDLC_POS:
                case ERF_TYPE_MC_HDLC:
                        p->dlt_list[dlt_index++] = DLT_CHDLC;
                        p->dlt_list[dlt_index++] = DLT_PPP_SERIAL;
                        p->dlt_list[dlt_index++] = DLT_FRELAY;
                        p->dlt_list[dlt_index++] = DLT_MTP2;
                        p->dlt_list[dlt_index++] = DLT_MTP2_WITH_PHDR;
                        p->dlt_list[dlt_index++] = DLT_LAPD;
                        if(!p->linktype)
                                p->linktype = DLT_CHDLC;
                        break;

                case ERF_TYPE_IPV4:
                        p->dlt_list[dlt_index++] = DLT_RAW;
                        p->dlt_list[dlt_index++] = DLT_IPV4;
                        if(!p->linktype)
                                p->linktype = DLT_RAW;
                        break;

                case ERF_TYPE_IPV6:
                        p->dlt_list[dlt_index++] = DLT_RAW;
                        p->dlt_list[dlt_index++] = DLT_IPV6;
                        if(!p->linktype)
                                p->linktype = DLT_RAW;
                        break;

                case ERF_TYPE_LEGACY:
                case ERF_TYPE_MC_RAW:
                case ERF_TYPE_MC_RAW_CHANNEL:
                case ERF_TYPE_IP_COUNTER:
                case ERF_TYPE_TCP_FLOW_COUNTER:
                case ERF_TYPE_INFINIBAND:
                case ERF_TYPE_RAW_LINK:
                case ERF_TYPE_INFINIBAND_LINK:
                case ERF_TYPE_META:
                default:
                        /* Libpcap cannot deal with these types yet */
                        /* Add no 'native' DLTs, but still covered by DLT_ERF */
                        break;

                } /* switch */
                index++;
        }

        p->dlt_list[dlt_index++] = DLT_ERF;

        p->dlt_count = dlt_index;

        if(!p->linktype)
                p->linktype = DLT_ERF;

        return p->linktype;
}

#ifdef DAG_ONLY
/*
 * This libpcap build supports only DAG cards, not regular network
 * interfaces.
 */

/*
 * There are no regular interfaces, just DAG interfaces.
 */
int
pcapint_platform_finddevs(pcap_if_list_t *devlistp _U_, char *errbuf _U_)
{
        return (0);
}

/*
 * Attempts to open a regular interface fail.
 */
pcap_t *
pcapint_create_interface(const char *device _U_, char *errbuf)
{
        snprintf(errbuf, PCAP_ERRBUF_SIZE, PCAP_ENODEV_MESSAGE, "DAG");
        return NULL;
}

/*
 * Libpcap version string.
 */
const char *
pcap_lib_version(void)
{
        return (PCAP_VERSION_STRING " (DAG-only)");
}
#endif