/* Determines how much data is available for reading on the DAG card and
* updates the various offsets accordingly */
static int dag_available(libtrace_t *libtrace) {
if (FORMAT_DATA->diff > 0)
return FORMAT_DATA->diff;
FORMAT_DATA->bottom = FORMAT_DATA->top;
FORMAT_DATA->top = dag_offset(
FORMAT_DATA->fd,
&(FORMAT_DATA->bottom),
DAGF_NONBLOCK);
FORMAT_DATA->diff = FORMAT_DATA->top - FORMAT_DATA->bottom;
FORMAT_DATA->offset = 0;
return FORMAT_DATA->diff;
}
static int legacy_read_packet(struct dag_context* cap, unsigned char* dst, struct cap_header* head){
const ssize_t diff = cap->top - cap->bottom;
/* no packet in buffer */
if ( diff < dag_record_size ){
cap->top = dag_offset(cap->fd, &cap->bottom, 0);
return 0; /* process eventual packages in the next batch */
}
dag_record_t* dr = (dag_record_t *)(cap->buffer + cap->bottom);
const size_t rlen = ntohs(dr->rlen);
/* not enough data in buffer */
if ( diff < rlen ){
cap->top = dag_offset(cap->fd, &cap->bottom, 0);
return 0; /* process eventual packages in the next batch */
}
/* process packet */
int ret = process_packet(cap, dr, dst, head);
cap->bottom += rlen; /* advance read position */
return ret;
}
/*
* Read at most max_packets from the capture stream and call the callback
* for each of them. Returns the number of packets handled, -1 if an
* error occured, or -2 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)
{
unsigned int processed = 0;
int flags = p->md.dag_offset_flags;
unsigned int nonblocking = flags & DAGF_NONBLOCK;
/* Get the next bufferful of packets (if necessary). */
while (p->md.dag_mem_top - p->md.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 -2 to indicate that
* we were told to break out of the loop.
*/
p->break_loop = 0;
return -2;
}
#ifdef HAVE_DAG_STREAMS_API
/* 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.
*/
p->md.dag_mem_top = dag_advance_stream(p->fd, p->md.dag_stream, &(p->md.dag_mem_bottom));
#else
/* dag_offset does not support timeouts */
p->md.dag_mem_top = dag_offset(p->fd, &(p->md.dag_mem_bottom), flags);
#endif /* HAVE_DAG_STREAMS_API */
if (nonblocking && (p->md.dag_mem_top - p->md.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 &&
p->md.dag_timeout &&
(p->md.dag_mem_top - p->md.dag_mem_bottom < dag_record_size))
{
/* Blocking mode, but timeout set and no data has arrived, return anyway.*/
return 0;
}
}
/* Process the packets. */
while (p->md.dag_mem_top - p->md.dag_mem_bottom >= dag_record_size) {
unsigned short packet_len = 0;
int caplen = 0;
struct pcap_pkthdr pcap_header;
#ifdef HAVE_DAG_STREAMS_API
dag_record_t *header = (dag_record_t *)(p->md.dag_mem_bottom);
#else
dag_record_t *header = (dag_record_t *)(p->md.dag_mem_base + p->md.dag_mem_bottom);
#endif /* HAVE_DAG_STREAMS_API */
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 -2 to indicate that
* we were told to break out of the loop.
*/
p->break_loop = 0;
return -2;
}
rlen = ntohs(header->rlen);
if (rlen < dag_record_size)
{
strncpy(p->errbuf, "dag_read: record too small", PCAP_ERRBUF_SIZE);
return -1;
}
p->md.dag_mem_bottom += rlen;
switch(header->type) {
case TYPE_ATM:
#ifdef TYPE_AAL5
case TYPE_AAL5:
if (header->type == TYPE_AAL5) {
packet_len = ntohs(header->wlen);
caplen = rlen - dag_record_size;
}
#endif
#ifdef TYPE_MC_ATM
case TYPE_MC_ATM:
if (header->type == TYPE_MC_ATM) {
caplen = packet_len = ATM_CELL_SIZE;
dp+=4;
}
#endif
#ifdef TYPE_MC_AAL5
case TYPE_MC_AAL5:
if (header->type == TYPE_MC_AAL5) {
packet_len = ntohs(header->wlen);
caplen = rlen - dag_record_size - 4;
dp+=4;
}
#endif
if (header->type == 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(*((unsigned long *)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 {
packet_len -= ATM_HDR_SIZE;
caplen -= ATM_HDR_SIZE;
dp += ATM_HDR_SIZE;
}
break;
#ifdef TYPE_COLOR_ETH
case TYPE_COLOR_ETH:
#endif
case TYPE_ETH:
packet_len = ntohs(header->wlen);
packet_len -= (p->md.dag_fcs_bits >> 3);
caplen = rlen - dag_record_size - 2;
if (caplen > packet_len) {
caplen = packet_len;
}
dp += 2;
break;
#ifdef TYPE_COLOR_HDLC_POS
case TYPE_COLOR_HDLC_POS:
#endif
case TYPE_HDLC_POS:
packet_len = ntohs(header->wlen);
packet_len -= (p->md.dag_fcs_bits >> 3);
caplen = rlen - dag_record_size;
if (caplen > packet_len) {
caplen = packet_len;
}
break;
#ifdef TYPE_MC_HDLC
case TYPE_MC_HDLC:
packet_len = ntohs(header->wlen);
packet_len -= (p->md.dag_fcs_bits >> 3);
caplen = rlen - dag_record_size - 4;
if (caplen > packet_len) {
caplen = packet_len;
}
dp += 4;
break;
#endif
}
if (caplen > p->snapshot)
caplen = p->snapshot;
/* Count lost packets. */
switch(header->type) {
#ifdef TYPE_COLOR_HDLC_POS
/* in this type the color value overwrites the lctr */
case TYPE_COLOR_HDLC_POS:
break;
#endif
#ifdef TYPE_COLOR_ETH
/* in this type the color value overwrites the lctr */
case TYPE_COLOR_ETH:
break;
#endif
default:
if (header->lctr) {
if (p->md.stat.ps_drop > (UINT_MAX - ntohs(header->lctr))) {
p->md.stat.ps_drop = UINT_MAX;
} else {
p->md.stat.ps_drop += ntohs(header->lctr);
}
}
}
/* Run the packet filter if there is one. */
if ((p->fcode.bf_insns == NULL) || bpf_filter(p->fcode.bf_insns, dp, packet_len, caplen)) {
/* convert between timestamp formats */
register unsigned long long ts;
if (IS_BIGENDIAN()) {
ts = SWAP_TS(header->ts);
} else {
ts = header->ts;
}
pcap_header.ts.tv_sec = ts >> 32;
ts = (ts & 0xffffffffULL) * 1000000;
ts += 0x80000000; /* rounding */
pcap_header.ts.tv_usec = ts >> 32;
if (pcap_header.ts.tv_usec >= 1000000) {
pcap_header.ts.tv_usec -= 1000000;
pcap_header.ts.tv_sec++;
}
/* Fill in our own header data */
pcap_header.caplen = caplen;
pcap_header.len = packet_len;
/* Count the packet. */
p->md.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)
{
/* Reached the user-specified limit. */
return cnt;
}
}
}
/*
* Read at most max_packets from the capture stream and call the callback
* for each of them. Returns the number of packets handled, -1 if an
* error occured, or -2 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;
unsigned int processed = 0;
int flags = pd->dag_offset_flags;
unsigned int nonblocking = 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 -2 to indicate that
* we were told to break out of the loop.
*/
p->break_loop = 0;
return -2;
}
#ifdef HAVE_DAG_STREAMS_API
/* 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 -1;
}
#else
/* dag_offset does not support timeouts */
pd->dag_mem_top = dag_offset(p->fd, &(pd->dag_mem_bottom), flags);
#endif /* HAVE_DAG_STREAMS_API */
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. */
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;
#ifdef HAVE_DAG_STREAMS_API
dag_record_t *header = (dag_record_t *)(pd->dag_mem_bottom);
#else
dag_record_t *header = (dag_record_t *)(pd->dag_mem_base + pd->dag_mem_bottom);
#endif /* HAVE_DAG_STREAMS_API */
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 -2 to indicate that
* we were told to break out of the loop.
*/
p->break_loop = 0;
return -2;
}
rlen = ntohs(header->rlen);
if (rlen < dag_record_size)
{
strncpy(p->errbuf, "dag_read: record too small", PCAP_ERRBUF_SIZE);
return -1;
}
pd->dag_mem_bottom += rlen;
/* Count lost packets. */
switch((header->type & 0x7f)) {
/* in these types the color value overwrites the lctr */
case TYPE_COLOR_HDLC_POS:
case TYPE_COLOR_ETH:
case TYPE_DSM_COLOR_HDLC_POS:
case TYPE_DSM_COLOR_ETH:
case TYPE_COLOR_MC_HDLC_POS:
case TYPE_COLOR_HASH_ETH:
case TYPE_COLOR_HASH_POS:
break;
default:
if (header->lctr) {
if (pd->stat.ps_drop > (UINT_MAX - ntohs(header->lctr))) {
pd->stat.ps_drop = UINT_MAX;
} else {
pd->stat.ps_drop += ntohs(header->lctr);
}
}
}
if ((header->type & 0x7f) == 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 ((header->type & 0x7f)) {
case TYPE_MC_AAL5:
case TYPE_MC_ATM:
case TYPE_MC_HDLC:
case TYPE_MC_RAW_CHANNEL:
case TYPE_MC_RAW:
case TYPE_MC_AAL2:
case TYPE_COLOR_MC_HDLC_POS:
packet_len += 4; /* MC header */
break;
case TYPE_COLOR_HASH_ETH:
case TYPE_DSM_COLOR_ETH:
case TYPE_COLOR_ETH:
case 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((header->type & 0x7f)) {
case TYPE_ATM:
case TYPE_AAL5:
if (header->type == TYPE_AAL5) {
packet_len = ntohs(header->wlen);
caplen = rlen - dag_record_size;
}
case TYPE_MC_ATM:
if (header->type == TYPE_MC_ATM) {
caplen = packet_len = ATM_CELL_SIZE;
dp+=4;
}
case TYPE_MC_AAL5:
if (header->type == 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 (header->type == 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(*((unsigned long *)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 {
packet_len -= ATM_HDR_SIZE;
caplen -= ATM_HDR_SIZE;
dp += ATM_HDR_SIZE;
}
break;
case TYPE_COLOR_HASH_ETH:
case TYPE_DSM_COLOR_ETH:
case TYPE_COLOR_ETH:
case TYPE_ETH:
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 TYPE_COLOR_HASH_POS:
case TYPE_DSM_COLOR_HDLC_POS:
case TYPE_COLOR_HDLC_POS:
case TYPE_HDLC_POS:
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 TYPE_COLOR_MC_HDLC_POS:
case TYPE_MC_HDLC:
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;
#ifdef DLT_MTP2_WITH_PHDR
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;
}
#endif
break;
case TYPE_IPV4:
case TYPE_IPV6:
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 TYPE_MC_RAW:
case TYPE_MC_RAW_CHANNEL:
case TYPE_IP_COUNTER:
case TYPE_TCP_FLOW_COUNTER:
case TYPE_INFINIBAND:
case TYPE_RAW_LINK:
case TYPE_INFINIBAND_LINK:
default:
/* Unhandled ERF type.
* Ignore rather than generating error
*/
continue;
} /* switch type */
} /* ERF encapsulation */
