tree_cell * nasl_telnet_init(lex_ctxt * lexic)
{
int soc = get_int_var_by_num(lexic, 0, -1);
int opts; /* number of options recorded */
unsigned char buffer[1024];
#define iac buffer[0]
#define code buffer[1]
#define option buffer[2]
tree_cell * retc;
int n = 0, n2;
if(soc <= 0 )
{
nasl_perror(lexic, "Syntax error in the telnet_init() function\n");
nasl_perror(lexic, "Correct syntax is : output = telnet_init(<socket>)\n");
return NULL;
}
iac = 255;
opts = 0;
while(iac == 255)
{
n = read_stream_connection_min(soc, buffer, 3, 3);
if((iac!=255)||(n<=0)||(n!=3))break;
if((code == 251)||(code == 252))code = 254; /* WILL , WONT -> DON'T */
else if((code == 253)||(code == 254))code = 252; /* DO,DONT -> WONT */
write_stream_connection(soc, buffer,3);
opts++;
if (opts>100) break;
}
if (n <= 0)
{
if (opts == 0)
return NULL;
else
n = 0;
}
if (opts>100) /* remote telnet server is crazy */
{
nasl_perror(lexic, "More than 100 options received by telnet_init() function! exiting telnet_init.\n");
return NULL;
}
n2 = read_stream_connection(soc, buffer + n, sizeof(buffer) - n);
if (n2 > 0)
n += n2;
retc = alloc_typed_cell(CONST_DATA);
retc->size = n;
retc->x.str_val = strndup(buffer, n);
#undef iac
#undef data
#undef option
return retc;
}
tree_cell * nasl_recv_line(lex_ctxt * lexic)
{
int len = get_int_local_var_by_name(lexic, "length", -1);
int soc = get_int_local_var_by_name(lexic, "socket", 0);
int timeout = get_int_local_var_by_name(lexic, "timeout", -1);
char * data;
int new_len = 0;
int n = 0;
tree_cell * retc;
time_t t1 = 0;
if(timeout < 0) timeout = lexic->recv_timeout;
if(len == -1 || soc <= 0)
{
nasl_perror(lexic, "recv_line: missing or undefined parameter length or soc\n");
return NULL;
}
if (timeout >= 0) /* sycalls are much more expensive than simple tests */
t1 = time(NULL);
if ( fd_is_stream(soc) != 0 )
{
int bufsz = stream_get_buffer_sz ( soc );
if ( bufsz <= 0 )
stream_set_buffer(soc, len + 1 );
}
data = emalloc(len+1);
for(;;)
{
int e = read_stream_connection_min(soc, data+n, 1, 1);
if(e < 0)
break;
if(e == 0)
{
if( timeout >= 0 && time(NULL) - t1 < timeout)
continue;
else
break;
}
n++;
if((data[n-1] == '\n') ||
(n >= len))break;
}
if(n <= 0)
{
efree(&data);
return NULL;
}
new_len = n;
retc = alloc_tree_cell(0, NULL);
retc->type = CONST_DATA;
retc->size = new_len;
retc->x.str_val = nasl_strndup(data, new_len);
efree(&data);
return retc;
}
tree_cell * nasl_recv(lex_ctxt * lexic)
{
char * data;
int len = get_int_local_var_by_name(lexic, "length", -1);
int min_len = get_int_local_var_by_name(lexic, "min", -1);
int soc = get_int_local_var_by_name(lexic, "socket", 0);
int to = get_int_local_var_by_name(lexic, "timeout", lexic->recv_timeout);
fd_set rd;
struct timeval tv;
int new_len = 0;
tree_cell * retc;
int type = -1, opt_len = sizeof(type);
int e;
if(len <= 0 || soc <= 0)
return NULL;
if (to <= 0) to = 5;
tv.tv_sec = to;
tv.tv_usec = 0;
data = emalloc(len);
if ( !fd_is_stream(soc) )
e = getsockopt(soc, SOL_SOCKET, SO_TYPE, &type, &opt_len);
else
e = -1;
if(e == 0 && type == SOCK_DGRAM)
{
/*
* As UDP packets may be lost, we retry up to 5 times
*/
int retries = 5;
int i;
tv.tv_sec = to / retries;
tv.tv_usec = (to % retries) * 100000;
for(i=0;i<retries;i++)
{
FD_ZERO(&rd);
FD_SET(soc, &rd);
if(!to || select(soc+1, &rd, NULL, NULL, &tv)>0)
{
int e;
e = recv(soc, data+new_len, len-new_len, 0);
if(e <= 0)
{
if(!new_len)
{
efree(&data);
return NULL;
}
else break;
}
else new_len+=e;
if(new_len >= len)break;
break; /* UDP data is never fragmented */
}
else
{
/*
* The packet may have been lost en route - we resend it
*/
char * data;
int len;
data = get_udp_data(lexic->script_infos, soc, &len);
if(data != NULL)send(soc, data, len, 0);
tv.tv_sec = to / retries;
tv.tv_usec = ( to % retries) * 100000;
}
}
}
else {
int old = stream_set_timeout(soc, tv.tv_sec);
new_len = read_stream_connection_min(soc, data, min_len, len);
stream_set_timeout(soc, old);
}
if(new_len > 0)
{
retc = alloc_tree_cell(0, NULL);
retc->type = CONST_DATA;
retc->x.str_val = nasl_strndup(data, new_len);
retc->size = new_len;
efree(&data);
return retc;
}
else {
efree(&data);
return NULL;
}
}
