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Got some padding and option reading stuff out of the way

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XANTRONIX Development 2019-01-24 01:26:44 -06:00
parent d97799cbe0
commit f70d13c541
3 changed files with 71 additions and 45 deletions
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60
examples/pcapread.c
View file

@ -23,14 +23,43 @@ static void usage(int argc, char **argv, const char *message, ...) {
exit(1);
}
static ssize_t handle_options(hexagram_pcapng_stream *stream,
uint32_t type,
uint16_t code,
uint16_t len) {
ssize_t readlen;
uint8_t data[65535];
if ((readlen = read(stream->fd, data, (size_t)len)) < 0) {
goto error_io;
}
if (type == HEXAGRAM_PCAPNG_BLOCK_IF) {
if (code == HEXAGRAM_PCAPNG_OPTION_IF_TSRESOL) {
stream->if_tsresol = data[0];
}
}
stream->error = HEXAGRAM_PCAPNG_ERROR_OK;
return readlen;
error_io:
stream->error = HEXAGRAM_PCAPNG_ERROR_IO;
return -1;
}
static ssize_t handle_block(hexagram_pcapng_stream *stream,
uint32_t type,
size_t len) {
hexagram_pcapng_packet header;
uint8_t body[65535];
ssize_t readlen,
remaining = len;
size_t remaining = len;
ssize_t total = 0,
readlen;
/*
* If we've received anything other than a packet block, then seek past
@ -40,13 +69,13 @@ static ssize_t handle_block(hexagram_pcapng_stream *stream,
printf("Read block type %08"PRIx32" len %zu\n",
type, len);
if (lseek(stream->fd, len, SEEK_CUR) < 0) {
if ((readlen = lseek(stream->fd, len, SEEK_CUR)) < 0) {
perror("lseek()");
goto error_io;
}
return 0;
return readlen;
}
/*
@ -59,6 +88,7 @@ static ssize_t handle_block(hexagram_pcapng_stream *stream,
goto error_io;
} else {
remaining -= readlen;
total += readlen;
}
/*
@ -70,24 +100,38 @@ static ssize_t handle_block(hexagram_pcapng_stream *stream,
goto error_io;
} else {
remaining -= readlen;
total += readlen;
}
printf("Read packet %"PRIu32" bytes time hi %"PRIu32" lo %"PRIu32"\n",
header.caplen, header.timestamp[0], header.timestamp[1]);
if (header.caplen % sizeof(uint32_t)) {
size_t padding = sizeof(uint32_t) - (header.caplen % sizeof(uint32_t));
if (lseek(stream->fd, padding, SEEK_CUR) < 0) {
perror("lseek()");
goto error_io;
} else {
remaining -= padding;
total += padding;
}
}
/*
* The remaining data here should be pcapng option values, and since we do
* not presently require them, we can safely seek past them.
*/
if (lseek(stream->fd, remaining, SEEK_CUR) < 0) {
perror("lseek()");
if ((readlen = hexagram_pcapng_read_options(stream, handle_options, type, remaining)) < 0) {
goto error_io;
} else {
total += readlen;
}
stream->error = HEXAGRAM_PCAPNG_ERROR_OK;
return 0;
return total;
error_io:
stream->error = HEXAGRAM_PCAPNG_ERROR_IO;

7
include/hexagram/pcapng.h
View file

@ -24,7 +24,7 @@ typedef ssize_t (hexagram_pcapng_block_handler)(hexagram_pcapng_stream *,
size_t length);
typedef ssize_t (hexagram_pcapng_option_handler)(hexagram_pcapng_stream *,
hexagram_pcapng_block_header *,
uint32_t type,
uint16_t code,
uint16_t length);
@ -35,4 +35,9 @@ void hexagram_pcapng_stream_destroy(hexagram_pcapng_stream *stream);
ssize_t hexagram_pcapng_stream_read(hexagram_pcapng_stream *stream,
hexagram_pcapng_block_handler *handler);
ssize_t hexagram_pcapng_read_options(hexagram_pcapng_stream *stream,
hexagram_pcapng_option_handler *handler,
uint32_t type,
size_t len);
#endif /* _HEXAGRAM_PCAPNG_H */

41
src/pcapng.c
View file

@ -8,36 +8,9 @@
#include <hexagram/pcapng.h>
static ssize_t handle_option(hexagram_pcapng_stream *stream,
hexagram_pcapng_block_header *header,
uint16_t code,
uint16_t len) {
ssize_t readlen;
uint8_t data[65535];
if ((readlen = read(stream->fd, data, (size_t)len)) < 0) {
goto error_io;
}
if (header->type == HEXAGRAM_PCAPNG_BLOCK_IF) {
if (code == HEXAGRAM_PCAPNG_OPTION_IF_TSRESOL) {
stream->if_tsresol = data[0];
}
}
stream->error = HEXAGRAM_PCAPNG_ERROR_OK;
return readlen;
error_io:
stream->error = HEXAGRAM_PCAPNG_ERROR_IO;
return -1;
}
static ssize_t read_options(hexagram_pcapng_stream *stream,
hexagram_pcapng_block_header *header,
ssize_t hexagram_pcapng_read_options(hexagram_pcapng_stream *stream,
hexagram_pcapng_option_handler *handler,
uint32_t type,
size_t len) {
hexagram_pcapng_option option;
ssize_t total = 0;
@ -53,7 +26,7 @@ static ssize_t read_options(hexagram_pcapng_stream *stream,
total += readlen;
}
if ((readlen = handler(stream, header, option.code, option.length)) < 0) {
if ((readlen = handler(stream, type, option.code, option.length)) < 0) {
goto error_io;
} else if (readlen < option.length) {
stream->error = HEXAGRAM_PCAPNG_ERROR_TRUNCATED;
@ -63,10 +36,14 @@ static ssize_t read_options(hexagram_pcapng_stream *stream,
total += readlen;
}
if ((readlen = lseek(stream->fd, option.length % sizeof(uint32_t), SEEK_CUR)) < 0) {
if (option.length % sizeof(uint32_t)) {
size_t padding = sizeof(uint32_t) - (option.length % sizeof(uint32_t));
if ((readlen = lseek(stream->fd, padding, SEEK_CUR)) < 0) {
goto error_io;
} else {
total += readlen;
total += padding;
}
}
}