/**
* Configure the user supplied buffer.
*/
static ag_bool
fmem_config_user_buf(fmem_cookie_t * pFMC, void * buf, ssize_t len)
{
/*
* User allocated buffer. User responsible for disposal.
*/
if (len == 0) {
free(pFMC);
errno = EINVAL;
return AG_FALSE;
}
pFMC->buffer = (buf_bytes_t*)buf;
/* Figure out where our "next byte" and EOF are.
* Truncated files start at the beginning.
*/
if (pFMC->mode & FLAG_BIT(truncate)) {
/*
* "write" mode
*/
pFMC->eof = \
pFMC->next_ix = 0;
}
else if (pFMC->mode & FLAG_BIT(binary)) {
pFMC->eof = len;
pFMC->next_ix = (pFMC->mode & FLAG_BIT(append)) ? len : 0;
} else {
/*
* append or read text mode -- find the end of the buffer
* (the first NUL character)
*/
buf_bytes_t *p = (buf_bytes_t*)buf;
pFMC->eof = 0;
while ((*p != NUL) && (++(pFMC->eof) < len)) p++;
pFMC->next_ix =
(pFMC->mode & FLAG_BIT(append)) ? pFMC->eof : 0;
}
/*
* text mode - NUL terminate buffer, if it fits.
*/
if ( ((pFMC->mode & FLAG_BIT(binary)) == 0)
&& (pFMC->next_ix < len)) {
pFMC->buffer[pFMC->next_ix] = NUL;
}
pFMC->buf_size = len;
return AG_TRUE;
}
/**
* Convert a mode string into mode bits.
*/
static int
fmem_getmode(char const * mode, mode_bits_t * pRes)
{
if (mode == NULL)
return 1;
switch (*mode) {
case 'a': *pRes = FLAG_BIT(write) | FLAG_BIT(append);
break;
case 'w': *pRes = FLAG_BIT(write) | FLAG_BIT(truncate);
break;
case 'r': *pRes = FLAG_BIT(read);
break;
default: return EINVAL;
}
/*
* If someone wants to supply a "wxxbxbbxbb+" mode string, I don't care.
*/
for (;;) {
switch (*++mode) {
case '+': *pRes |= FLAG_BIT(read) | FLAG_BIT(write);
if (mode[1] != NUL)
return EINVAL;
break;
case NUL: break;
case 'b': *pRes |= FLAG_BIT(binary); continue;
case 'x': continue;
default: return EINVAL;
}
break;
}
return 0;
}
/**
* Allocate an initial buffer for fmem.
*/
static ag_bool
fmem_alloc_buf(fmem_cookie_t * pFMC, ssize_t len)
{
/*
* We must allocate the buffer. If "len" is zero, set it to page size.
*/
pFMC->mode |= FLAG_BIT(allocated);
if (len == 0)
len = pFMC->pg_size;
/*
* Unallocated file space is set to NULs. Emulate that.
*/
pFMC->buffer = calloc((size_t)1, (size_t)len);
if (pFMC->buffer == NULL) {
errno = ENOMEM;
free(pFMC);
return AG_FALSE;
}
/*
* We've allocated the buffer. The end of file and next entry
* are both zero.
*/
pFMC->next_ix = 0;
pFMC->eof = 0;
pFMC->buf_size = len;
return AG_TRUE;
}
int
main(int argc, char **argv)
{
int flags = 0;
int c = 0;
extern char *optarg;
char *filter = NULL;
while ((c = getopt(argc, argv, "pf:")) != -1) {
switch (c) {
case 'p':
flags |= FLAG_BIT(FLAG_PROMISC);
break;
case 'f':
filter = strdup(optarg);
break;
default:
usage(argv[0]);
exit(-1);
break; /* not reached */
}
}
if (filter == NULL) {
filter = "ip";
}
process(flags, filter);
return (0);
}
/**
* Extend the space associated with an fmem file.
*/
static int
fmem_extend(fmem_cookie_t *pFMC, size_t new_size)
{
size_t ns = (new_size + (pFMC->pg_size - 1)) & (~(pFMC->pg_size - 1));
/*
* We can expand the buffer only if we are in append mode.
*/
if (pFMC->mode & FLAG_BIT(fixed_size))
goto no_space;
if ((pFMC->mode & FLAG_BIT(allocated)) == 0) {
/*
* Previously, this was a user supplied buffer. We now move to one
* of our own. The user is responsible for the earlier memory.
*/
void* bf = malloc(ns);
if (bf == NULL)
goto no_space;
memcpy(bf, pFMC->buffer, pFMC->buf_size);
pFMC->buffer = bf;
pFMC->mode |= FLAG_BIT(allocated);
}
else {
void* bf = realloc(pFMC->buffer, ns);
if (bf == NULL)
goto no_space;
pFMC->buffer = bf;
}
/*
* Unallocated file space is set to zeros. Emulate that.
*/
memset(pFMC->buffer + pFMC->buf_size, 0, ns - pFMC->buf_size);
pFMC->buf_size = ns;
return 0;
no_space:
errno = ENOSPC;
return -1;
}
/**
* Free up the memory associated with an fmem file.
* If the user is managing the space, then the allocated bit is set.
*/
static int
fmem_close(void * cookie)
{
fmem_cookie_t * pFMC = cookie;
cookie_fp_map_t * pmap = (void *)map;
unsigned int mct = map_ct;
while (mct-- != 0) {
if (pmap->cookie == cookie) {
*pmap = map[--map_ct];
break;
}
pmap++;
}
if (mct > map_ct)
errno = EINVAL;
if (pFMC->mode & FLAG_BIT(allocated))
free(pFMC->buffer);
free(pFMC);
return 0;
}
/*=export_func ag_fmemopen
*
* what: Open a stream to a string
*
* arg: + void* + buf + buffer to use for i/o +
* arg: + ssize_t + len + size of the buffer +
* arg: + char* + mode + mode string, a la fopen(3C) +
*
* ret-type: FILE*
* ret-desc: a stdio FILE* pointer
*
* err: NULL is returned and errno is set to @code{EINVAL} or @code{ENOSPC}.
*
* doc:
*
* This function requires underlying @var{libc} functionality:
* either @code{fopencookie(3GNU)} or @code{funopen(3BSD)}.
*
* If @var{buf} is @code{NULL}, then a buffer is allocated. The initial
* allocation is @var{len} bytes. If @var{len} is less than zero, then the
* buffer will be reallocated as more space is needed. Any allocated
* memory is @code{free()}-ed when @code{fclose(3C)} is called.
*
* If @code{buf} is not @code{NULL}, then @code{len} must not be zero.
* It may still be less than zero to indicate that the buffer may
* be reallocated.
*
* The mode string is interpreted as follows. If the first character of
* the mode is:
*
* @table @code
* @item a
* Then the string is opened in "append" mode. In binary mode, "appending"
* will begin from the end of the initial buffer. Otherwise, appending will
* start at the first NUL character in the initial buffer (or the end of the
* buffer if there is no NUL character). Do not use fixed size buffers
* (negative @var{len} lengths) in append mode.
*
* @item w
* Then the string is opened in "write" mode. Any initial buffer is presumed
* to be empty.
*
* @item r
* Then the string is opened in "read" mode.
* @end table
*
* @noindent
* If it is not one of these three, the open fails and @code{errno} is
* set to @code{EINVAL}. These initial characters may be followed by:
*
* @table @code
* @item +
* The buffer is marked as updatable and both reading and writing is enabled.
*
* @item b
* The I/O is marked as "binary" and a trailing NUL will not be inserted
* into the buffer. Without this mode flag, one will be inserted after the
* @code{EOF}, if it fits. It will fit if the buffer is extensible (the
* provided @var{len} was negative). This mode flag has no effect if
* the buffer is opened in read-only mode.
*
* @item x
* This is ignored.
* @end table
*
* @noindent
* Any other letters following the inital 'a', 'w' or 'r' will cause an error.
=*/
FILE *
ag_fmemopen(void * buf, ssize_t len, char const * mode)
{
fmem_cookie_t *pFMC;
{
mode_bits_t bits;
if (fmem_getmode(mode, &bits) != 0) {
return NULL;
}
pFMC = malloc(sizeof(fmem_cookie_t));
if (pFMC == NULL) {
errno = ENOMEM;
return NULL;
}
pFMC->mode = bits;
}
/*
* Two more mode bits that do not come from the mode string:
* a negative size implies fixed size buffer and a NULL
* buffer pointer means we must allocate (and free) it.
*/
if (len <= 0) {
/*
* We only need page size if we might extend an allocation.
*/
len = -len;
pFMC->pg_size = getpagesize();
}
else {
pFMC->mode |= FLAG_BIT(fixed_size);
}
if (buf != NULL) {
if (! fmem_config_user_buf(pFMC, buf, len))
return NULL;
} else if ((pFMC->mode & (FLAG_BIT(append) | FLAG_BIT(truncate))) == 0) {
/*
* Not appending and not truncating. We must be reading.
* We also have no user supplied buffer. Nonsense.
*/
errno = EINVAL;
free(pFMC);
return NULL;
}
else if (! fmem_alloc_buf(pFMC, len))
return NULL;
#ifdef TEST_FMEMOPEN
saved_cookie = pFMC;
#endif
{
FILE * res;
cookie_read_function_t* pRd = (pFMC->mode & FLAG_BIT(read))
? (cookie_read_function_t*)fmem_read : NULL;
cookie_write_function_t* pWr = (pFMC->mode & FLAG_BIT(write))
? (cookie_write_function_t*)fmem_write : NULL;
#ifdef HAVE_FOPENCOOKIE
cookie_io_functions_t iof;
iof.read = pRd;
iof.write = pWr;
iof.seek = fmem_seek;
iof.close = fmem_close;
res = fopencookie(pFMC, mode, iof);
#else
res = funopen(pFMC, pRd, pWr, fmem_seek, fmem_close);
#endif
if (res == NULL)
return res;
if (++map_ct >= map_alloc_ct) {
void * p = (map_alloc_ct > 0)
? realloc((void *)map, (map_alloc_ct += 4) * sizeof(*map))
: malloc((map_alloc_ct = 4) * sizeof(*map));
if (p == NULL) {
fclose(res);
errno = ENOMEM; /* "fclose" set it to "EINVAL". */
return NULL;
}
map = p;
}
{
cookie_fp_map_t * p = (void *)(map + map_ct - 1);
p->fp = res;
p->cookie = pFMC;
}
return res;
}
}
/**
* Handle file system callback to write data to our string
*/
static ssize_t
fmem_write(void *cookie, const void *pBuf, size_t sz)
{
fmem_cookie_t *pFMC = cookie;
int add_nul_char;
/*
* In append mode, always seek to the end before writing.
*/
if (pFMC->mode & FLAG_BIT(append))
pFMC->next_ix = pFMC->eof;
/*
* Only add a NUL character if:
*
* * we are not in binary mode
* * there are data to write
* * the last character to write is not already NUL
*/
add_nul_char =
((pFMC->mode & FLAG_BIT(binary)) != 0)
&& (sz > 0)
&& (((char*)pBuf)[sz - 1] != NUL);
{
size_t next_pos = pFMC->next_ix + sz + add_nul_char;
if (next_pos > pFMC->buf_size) {
if (fmem_extend(pFMC, next_pos) != 0) {
/*
* We could not extend the memory. Try to write some data.
* Fail if we are either at the end or not writing data.
*/
if ((pFMC->next_ix >= pFMC->buf_size) || (sz == 0))
return -1; /* no space at all. errno is set. */
/*
* Never add the NUL for a truncated write. "sz" may be
* unchanged or limited here.
*/
add_nul_char = 0;
sz = pFMC->buf_size - pFMC->next_ix;
}
}
}
memcpy(pFMC->buffer + pFMC->next_ix, pBuf, sz);
pFMC->next_ix += sz;
/*
* Check for new high water mark and remember it. Add a NUL if
* we do that and if we have a new high water mark.
*/
if (pFMC->next_ix > pFMC->eof) {
pFMC->eof = pFMC->next_ix;
if (add_nul_char)
/*
* There is space for this NUL. The "add_nul_char" is not part of
* the "sz" that was added to "next_ix".
*/
pFMC->buffer[ pFMC->eof ] = NUL;
}
return sz;
}
void process(int flags)
{
char *interface=NULL;
char errbuf[PCAP_ERRBUF_SIZE];
struct bpf_program prog;
bpf_u_int32 network, netmask;
char *filter=NULL;
int flagdef;
filter="tcp";
signal(SIGHUP, SIG_IGN);
signal(SIGINT, signal_handler);
signal(SIGQUIT, signal_handler);
signal(SIGTERM, signal_handler);
/* Attempt to find the interface */
interface=pcap_lookupdev(errbuf);
if(interface==NULL) {
fprintf(stderr, "pcap_lookupdev: %s\n", errbuf);
exit(-1);
}
if(pcap_lookupnet(interface, &network, &netmask, errbuf) < 0) {
fprintf(stderr, "pcap_lookupnet: %s\n", errbuf);
exit(-1);
}
if(flags&FLAG_BIT(FLAG_PROMISC)) /* find out if we want to be promisc */
flagdef=1;
else
flagdef=0;
pcap_socket=pcap_open_live(interface, 1024, flagdef, 1024, errbuf);
if(pcap_socket==NULL) {
fprintf(stderr, "pcap_open_live: %s\n", errbuf);
exit(-1);
}
switch(pcap_datalink(pcap_socket)) {
case DLT_EN10MB:
dlt_len=14;
break;
case DLT_SLIP:
dlt_len=16;
break;
case DLT_PPP:
dlt_len=4;
break;
case DLT_FDDI:
fprintf(stderr, "Sorry, can't do FDDI\n");
signal_handler(-1);
break;
default:
dlt_len=4;
}
if(pcap_compile(pcap_socket, &prog, filter, 1, netmask) < 0) {
fprintf(stderr, "pcap_compile: %s\n", errbuf);
signal_handler(-1);
}
if(pcap_setfilter(pcap_socket, &prog) < 0) {
fprintf(stderr, "pcap_setfilter: %s\n", errbuf);
signal_handler(-1);
}
fprintf(stderr, "interface: %s, filter: %s, promiscuous: %s\n",
interface, filter, (flags&FLAG_BIT(FLAG_PROMISC))?"yes":"no");
for(;;)
pcap_loop(pcap_socket, -1, (pcap_handler)filter_packet, NULL);
}