hello,
how i will avoid this warning.

passing argument 2 of ‘memset’ makes integer from pointer without a cast


void
pt_delete(struct pt_context *pt, struct tcp_connection *c)
{
u_char key[KEY_BYTES];

/* if the trie is empty, just return */
if (pt->head == NULL)
{
return;
}

memset(key, NULL, KEY_BYTES);
pt_make_key(key, c);

/* call the recursive search and delete function */
if (pt_remove_r(pt, pt->head, key, NULL))
{
/*
* If we just deleted the last connection record in the trie
* then remove the last node so we have a totally empty trie.
*/
if (pt->n == 1 && (int)(pt->head->con) == CON_REMOVED)
{
free(pt->head);
pt->head = NULL;
pt->n = 0;
}
}
}

int
pt_find(struct pt_context *pt, struct tcp_connection *c,
struct tcp_connection **rc)
{
u_char key[KEY_BYTES];
struct pt_node *rn;
int r;

if (pt->head == NULL)
{

*rc = NULL;
return (0);
}

/* get a key for this connection */
memset(key, NULL, KEY_BYTES);
pt_make_key(key, c);

rn = NULL;
r = pt_search_r(pt->head, key, &rn);

*rc = rn->con;

return (r);
}

Use 0 instead:

hello,
thanks for your answer but i got one more warning. how i will deal with this..........

void
descry(u_char *u, struct pcap_pkthdr *phdr, u_char *packet)
{
struct libnet_ipv4_hdr *ip;
struct libnet_tcp_hdr *tcp;
struct descry_pack *gp;
struct tcp_connection *c;
struct tcp_connection *rc;
static u_char cleanup = 0;
struct timeval ts;

rc = NULL;
c = NULL;
gp = (struct descry_pack *)u;

/*
* In order to keep the trie from growing boundlessly, we need to
* periodically expire half open connections.
*/
if (cleanup++ > CLEANUP_INTERVAL)
{
ts.tv_usec = phdr->ts.tv_usec;
ts.tv_sec = phdr->ts.tv_sec;

/* expire old connections */
pt_expire(gp, &ts);
cleanup = 0;
}

/*
* Ignore packets that do not have an entire TCP header. Currently
* this code does not handle fragmented TCP headers and will not
* detect scans that use them.
*/
if (phdr->len < (gp->offset + LIBNET_IPV4_H + LIBNET_TCP_H))
{
return;
}

/* overlay IP and TCP headers */
ip = (struct libnet_ipv4_hdr *)(packet + gp->offset);
tcp = (struct libnet_tcp_hdr *)(packet + gp->offset +
(ip->ip_hl << 2));

/* shave off the lower order 6 bits containing the control flags */
switch (tcp->th_flags & 0x3F)
{
case (TH_SYN | TH_ACK):
/* this is a new connection to be added to the trie */

/* get memory for the connection state */
c = malloc(sizeof (struct tcp_connection ));
if (c == NULL)
{
return;
}

/* set connection state */
memcpy(&(c->ts), &(phdr->ts), sizeof(struct timeval));
/*
* The context for the connection state is biased towards
* the initiator of the TCP connection. Since this TCP
* segment is the SYN|ACK (response from server), we reverse
* the source and destination when filling in the connection
* information.
*/
SET_STATE(c, ip->ip_src.s_addr, tcp->th_sport,
ip->ip_dst.s_addr, tcp->th_dport, tcp->th_ack);

/* insert TCP connection into the trie */
if (pt_insert(gp->pt, c) == 0)
{
fprintf(stderr, "pt_insert() failed!\n");
}
break;
case (TH_FIN | TH_ACK):
case (TH_RST):
case (TH_RST | TH_ACK):
/* connection teardown */

/* get memory for the connection state */
c = malloc(sizeof (struct tcp_connection));
if (c == NULL)
{
return;
}
/* set connection state so we can search for the connection */
SET_STATE(c, ip->ip_dst.s_addr, tcp->th_dport,
ip->ip_src.s_addr, tcp->th_sport, tcp->th_seq);

/*
* Search the trie to see if this connection teadown
* corresponds to one of ours. We are looking for TCP
* connections where the initiator sends a SYN segment
* and the destination host is listening and responds
* with a SYN-ACK segment. Next the initiator closes the
* connection with a FIN-ACK, RST-ACK, or RST segment
* WITHOUT ever sending any data on the connection. This
* condition is usually a good indicator of someone doing
* a full-open (connect) port scan to see if a service is
* listening.
*/
if (pt_find(gp->pt, c, &rc))
{
check_state(gp, c, rc);
pt_delete(gp->pt, rc);
}
else
{
/*
* Did not find the connection. Assuming the initiator
* sent the teardown request, so we will try again
* while making the assumption that the server sent it.
*/
SET_STATE(c, ip->ip_src.s_addr, tcp->th_sport,
ip->ip_dst.s_addr, tcp->th_dport, tcp->th_ack);
pt_delete(gp->pt, c);
}
free(c);
break;
default:
break;
}
}

1) Use code tags! (#)
2) What's the warning message?
*) x++ increments after the fact, but ++x increments prior to the fact