static int cb(struct nfq_q_handle *qh, struct nfgenmsg *nfmsg,
struct nfq_data *nfa, void *data) {
u_int32_t id = 0;
int d;
struct nfqnl_msg_packet_hdr *ph;
ph = nfq_get_msg_packet_hdr(nfa);
if(ph) id = ntohl(ph->packet_id);
// verify some basic patterns and drop packet if it's
// somehow unexpected
if(verify_pkt(nfa) != 0)
return nfq_set_verdict(qh, id, NF_DROP, 0, NULL);
uint8_t ip_addr[4];
device_t dev;
uint16_t port;
if(get_info(nfa, &dev, ip_addr, &port) != 0)
return nfq_set_verdict(qh, id, NF_DROP, 0, NULL);
// check if this device already has an entry in the denied/allowed lists
for(d=0;d<allowed_len;d++) {
if(memcmp(allowed[d].hw_addr, dev.hw_addr, 6) == 0)
return nfq_set_verdict(qh, id, NF_ACCEPT, 0, NULL);
}
for(d=0;d<denied_len;d++)
if(memcmp(denied[d].hw_addr, dev.hw_addr, 6) == 0)
return nfq_set_verdict(qh, id, NF_DROP, 0, NULL);
// if we have a pending request then just drop everything
// elso until the current request has been answered
if(pending)
return nfq_set_verdict(qh, id, NF_DROP, 0, NULL);
pending = malloc(sizeof(device_t));
*pending = dev;
printf("REQ ");
// print the info
int i;
for (i = 0; i < 5; i++)
printf("%02x:", pending->hw_addr[i]);
printf("%02x ", pending->hw_addr[5]);
for (i = 0; i < 3; i++)
printf("%u.", ip_addr[i]);
printf("%u ", ip_addr[3]);
printf("%u\n", port);
printf("-> A(ccept), D(eny), I(gnore), Q(uit): ");
fflush(stdout);
// return nfq_set_verdict(qh, id, NF_ACCEPT, 0, NULL);
return nfq_set_verdict(qh, id, NF_DROP, 0, NULL);
}
/*
* This the main loop receiving, processing, and sending packets.
*/
int
serve(ndd_t *nds)
{
ndpkt_t *pkt;
int rc;
/*
* Since we process only packet at time, we need just one
* preallocated buffer.
*/
if ((pkt = (ndpkt_t *)malloc(ND_MAXPKT)) == NULL) {
log_msg(0, "Unable to allocate buffer: %s.",
strerror(errno));
return (1);
}
do {
ssize_t pkt_len;
int op, err;
/* Get packet from the network */
pkt_len = recv(nds->sc_fd, (void *)pkt, ND_MAXPKT, 0);
if (nds->exiting)
break;
if (pkt_len == -1) {
log_msg(0, "Unable to receive packet: %s.",
strerror(errno));
break;
}
/* Verify just received packet */
err = verify_pkt(pkt, pkt_len);
/* ND protocol supports only 2 operations: read and write */
op = pkt->np_op & ND_OP_CODE;
if (op == ND_OP_READ) {
rc = serve_read(nds, pkt, err);
} else if (op == ND_OP_WRITE) {
rc = serve_write(nds, pkt, err);
} else {
log_msg(1, "Unknown operation %d.", op);
rc = 1;
}
} while (rc == 0 && nds->exiting == 0);
free(pkt);
return (rc);
}