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[WIP/RFC] [skip ci] Add initial implementation for pcap-openvizsla module #840
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Original file line number | Diff line number | Diff line change |
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#ifdef HAVE_CONFIG_H | ||
#include <config.h> | ||
#endif | ||
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#include <errno.h> | ||
#include <stdlib.h> | ||
#include <string.h> | ||
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#include "pcap-int.h" | ||
#include "pcap-openvizsla.h" | ||
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#include <openvizsla.h> | ||
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#define OPENVIZSLA_IFACE "openvizsla" | ||
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struct pcap_openvizsla { | ||
enum ov_usb_speed usb_speed; | ||
struct ov_device* ov; | ||
}; | ||
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struct pcap_openvizsla_read { | ||
pcap_handler callback; | ||
u_char *user; | ||
}; | ||
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static void openvizsla_read_cb(struct ov_packet* packet, void* data) { | ||
struct pcap_openvizsla_read* r = (struct pcap_openvizsla_read*)data; | ||
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struct pcap_pkthdr pkth; | ||
pkth.caplen = ov_to_host_16(packet->size) + sizeof(struct ov_packet); | ||
pkth.len = pkth.caplen; | ||
pkth.ts.tv_sec = 0; | ||
pkth.ts.tv_usec = 0; | ||
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r->callback(r->user, &pkth, (const u_char*)packet); | ||
} | ||
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static int openvizsla_read(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) | ||
{ | ||
struct pcap_openvizsla* handlep = handle->priv; | ||
struct pcap_openvizsla_read r; | ||
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r.callback = callback; | ||
r.user = user; | ||
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int ret = 0; | ||
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if ((ret = ov_capture_start(handlep->ov, handle->buffer, handle->bufsize, openvizsla_read_cb, &r)) < 0) { | ||
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, | ||
"Can't start capture: %s", ov_get_error_string(handlep->ov)); | ||
return PCAP_ERROR; | ||
} | ||
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if ((ret = ov_capture_dispatch(handlep->ov, max_packets)) < 0) { | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Is there a way in which the callback routine can break out of the loop? If, for example, a callback routine calls There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more.
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if (handle->break_loop) { | ||
handle->break_loop = 0; | ||
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ov_capture_stop(handlep->ov); | ||
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return PCAP_ERROR_BREAK; | ||
} | ||
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snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, | ||
"An error occured during capturing: %s", ov_get_error_string(handlep->ov)); | ||
return PCAP_ERROR; | ||
} | ||
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ov_capture_stop(handlep->ov); | ||
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return ret; | ||
} | ||
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static void openvizsla_cleanup(pcap_t* handle) | ||
{ | ||
struct pcap_openvizsla* handlep = handle->priv; | ||
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ov_free(handlep->ov); | ||
pcap_cleanup_live_common(handle); | ||
} | ||
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static void openvizsla_breakloop(pcap_t* handle) | ||
{ | ||
struct pcap_openvizsla* handlep = handle->priv; | ||
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ov_capture_breakloop(handlep->ov); | ||
pcap_breakloop_common(handle); | ||
} | ||
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static int openvizsla_activate(pcap_t* handle) | ||
{ | ||
struct pcap_openvizsla* handlep = handle->priv; | ||
int ret = 0; | ||
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if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN) | ||
handle->snapshot = MAXIMUM_SNAPLEN; | ||
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handle->bufsize = handle->snapshot; | ||
handle->offset = 0; | ||
handle->linktype = DLT_OPENVIZSLA; | ||
handle->buffer = malloc(handle->bufsize); | ||
if (!handle->buffer) { | ||
pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE, errno, "malloc"); | ||
goto fail_buffer_malloc; | ||
} | ||
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handle->cleanup_op = openvizsla_cleanup; | ||
handle->read_op = openvizsla_read; | ||
handle->setfilter_op = install_bpf_program; /* no kernel filtering */ | ||
handle->breakloop_op = openvizsla_breakloop; | ||
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handlep->ov = ov_new(NULL); | ||
if (!handlep->ov) { | ||
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, | ||
"Can't create OpenVizsla device handler"); | ||
goto fail_ov_init; | ||
} | ||
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ret = ov_open(handlep->ov); | ||
if (ret < 0) { | ||
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, | ||
"Can't open device: %s", ov_get_error_string(handlep->ov)); | ||
goto fail_ov_open; | ||
} | ||
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ret = ov_set_usb_speed(handlep->ov, handlep->usb_speed); | ||
if (ret < 0) { | ||
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, | ||
"Can't set USB speed: %s", ov_get_error_string(handlep->ov)); | ||
goto fail_ov_set_usb_speed; | ||
} | ||
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return 0; | ||
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fail_ov_set_usb_speed: | ||
fail_ov_open: | ||
ov_free(handlep->ov); | ||
fail_ov_init: | ||
free(handle->buffer); | ||
handle->buffer = NULL; | ||
fail_buffer_malloc: | ||
return PCAP_ERROR; | ||
} | ||
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int openvizsla_findalldevs(pcap_if_list_t *devlistp, char *err_str) | ||
{ | ||
/* Always find one device */ | ||
return 0; | ||
} | ||
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pcap_t *openvizsla_create(const char *device, char *ebuf, int *is_ours) | ||
{ | ||
const char *cp; | ||
char *cpend; | ||
long devnum; | ||
pcap_t *p; | ||
struct pcap_openvizsla* handlep; | ||
enum ov_usb_speed usb_speed; | ||
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cp = strrchr(device, '/'); | ||
if (cp == NULL) | ||
cp = device; | ||
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if (strncmp(cp, OPENVIZSLA_IFACE, sizeof (OPENVIZSLA_IFACE - 1)) != 0) { | ||
*is_ours = 0; | ||
return NULL; | ||
} | ||
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cp += sizeof OPENVIZSLA_IFACE - 1; | ||
devnum = strtol(cp, &cpend, 10); | ||
if (cpend == cp) { | ||
*is_ours = 0; | ||
return NULL; | ||
} | ||
if (devnum < 0) { | ||
*is_ours = 0; | ||
return NULL; | ||
} | ||
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switch (*cpend) { | ||
case '\0': /* Fallback to 'l' */ | ||
case 'l': { | ||
usb_speed = OV_LOW_SPEED; | ||
} break; | ||
case 'f': { | ||
usb_speed = OV_FULL_SPEED; | ||
} break; | ||
case 'h': { | ||
usb_speed = OV_HIGH_SPEED; | ||
} break; | ||
default: { | ||
*is_ours = 0; | ||
return NULL; | ||
} | ||
} | ||
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*is_ours = 1; | ||
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p = PCAP_CREATE_COMMON(ebuf, struct pcap_openvizsla); | ||
if (p == NULL) | ||
return NULL; | ||
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p->activate_op = openvizsla_activate; | ||
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handlep = p->priv; | ||
handlep->usb_speed = usb_speed; | ||
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return p; | ||
} |
Original file line number | Diff line number | Diff line change |
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/* | ||
* Prototypes for OpenVizsla-related functions | ||
*/ | ||
int openvizsla_findalldevs(pcap_if_list_t *devlistp, char *err_str); | ||
pcap_t *openvizsla_create(const char *device, char *ebuf, int *is_ours); |
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Can no time stamp be supplied?
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The device provides 24-bit timestamp with precision of
1/60 usec
. Unfortunately, this value wraps around many times during the capture. What would be preferred way to provide best possible timestamp (combining 24-bit timestamp and the host wall clock)?There was a problem hiding this comment.
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So the 24-bit timestamp goes back to zero about 3.58 times per second, is that correct? (If yes, then just a combination of UNIX time and the 24-bit timestamp does not tell the exact time when a packet was received, especially at less then 3.58 packets per second, it needs to be something else.)
Is there any way to keep the 24-bit timestamp in sync with the host clock, such as sending a pulse to the device every second or a fraction of a second?
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Correct. I think that the simplest way would be to use host receive UNIX timestamp and keep the counter as is.