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pcap-dag.c
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/*
* 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