int
main (void)
{
#define SIZE 100
int i;
printf ("point_t points[] = {\n");
for (i=0; i < 1000; i++) {
printf (" {%g,%g},", rand_within (SIZE), rand_within (SIZE));
if (i % 5 == 4)
printf ("\n");
}
printf ("};\n");
}
/*
* Function: return_neigh_adv()
*
* Description:
* This function returns neighbor advertisement message
* And this updates the gateway information.
*
* Argument:
* sd : socket to send arp reply message
* rcveth_p : pointer to ether frame data
* current_eth: current MAC address
* gateway_p : pointer to IPv6 gateway information
*
* Return value:
* None
*/
void
return_neigh_adv(int sd, struct eth_frame *rcveth_p,
struct ip6_gateway_info *gateway_p)
{
int retval;
struct ip6_datagram *rcvip6_p; /* IPv6 part of receiving frame */
struct neighbor_sol *rcvns_p; /* NS part of receiving frame */
unsigned char new_hd_addr[ETH_ALEN]; /* new MAC address */
struct in6_addr new_nexthop; /* new next hop */
size_t sndeth_size; /* size of sending frame */
struct eth_frame sndeth; /* sending frame */
struct ip6_datagram *sndip6_p; /* IPv6 part of sending frame */
struct pseudo_ip6_datagram p_ip6; /* pseudo IP header */
struct neighbor_adv *sndna_p; /* NA part of sending frame */
rcvip6_p = (struct ip6_datagram *)&(rcveth_p->data);
rcvns_p = (struct neighbor_sol *)&(rcvip6_p->payload);
/* If NS is DAD NS, do nothing */
if (memcmp
(&(rcvip6_p->hdr.ip6_src), &in6addr_any,
sizeof(struct in6_addr)) == 0) {
if (debug) {
fprintf(stderr, "Received NS is a DAD NS\n");
return;
}
}
/* Update the gateway information */
memset(new_hd_addr, '\0', ETH_ALEN); /* MAC address */
for (;;) {
new_hd_addr[3] = rand_within(0, 254);
new_hd_addr[4] = rand_within(0, 254);
new_hd_addr[5] = rand_within(1, 254);
if (memcmp(gateway_p->hd_addr, new_hd_addr, ETH_ALEN)) {
memcpy(gateway_p->hd_addr, new_hd_addr, ETH_ALEN);
break;
}
}
gateway_p->ip_addr = rcvns_p->defs.nd_ns_target; /* IP address */
for (;;) { /* next hop */
memset(&new_nexthop, '\0', sizeof(struct in6_addr));
new_nexthop.s6_addr[0] = 0xfe;
new_nexthop.s6_addr[1] = 0x80;
new_nexthop.s6_addr[15] = rand_within(1, 254);
if (memcmp
(&(gateway_p->nexthop), &new_nexthop,
sizeof(struct in6_addr))) {
gateway_p->nexthop = new_nexthop;
break;
}
}
/* Build a frame to send */
sndeth_size = sizeof(struct ethhdr) + sizeof(struct ip6_hdr)
+ sizeof(struct neighbor_adv);
memset(&sndeth, '\0', sizeof(struct eth_frame));
sndip6_p = (struct ip6_datagram *)&(sndeth.data);
sndna_p = (struct neighbor_adv *)&(sndip6_p->payload);
/* Ether */
memcpy(sndeth.hdr.h_dest, rcvns_p->src_laddr, ETH_ALEN);
memcpy(sndeth.hdr.h_source, gateway_p->hd_addr, ETH_ALEN);
sndeth.hdr.h_proto = htons(ETH_P_IPV6);
/* IPv6 */
sndip6_p->hdr.ip6_vfc = 6 << 4;
sndip6_p->hdr.ip6_flow |= 0;
sndip6_p->hdr.ip6_plen = htons(sizeof(struct neighbor_adv));
sndip6_p->hdr.ip6_nxt = IPPROTO_ICMPV6;
sndip6_p->hdr.ip6_hlim = 255;
sndip6_p->hdr.ip6_src = gateway_p->ip_addr;
sndip6_p->hdr.ip6_dst = rcvip6_p->hdr.ip6_src;
/* Neighbor Advertisement */
sndna_p->defs.nd_na_type = ND_NEIGHBOR_ADVERT;
sndna_p->defs.nd_na_code = 0;
sndna_p->defs.nd_na_cksum = 0; /* Calculate later */
sndna_p->defs.nd_na_target = gateway_p->ip_addr;
sndna_p->defs.nd_na_flags_reserved
= ND_NA_FLAG_ROUTER | ND_NA_FLAG_SOLICITED | ND_NA_FLAG_OVERRIDE;
sndna_p->tla_opt.nd_opt_type = ND_OPT_TARGET_LINKADDR;
sndna_p->tla_opt.nd_opt_len = 1;
memcpy(sndna_p->tgt_laddr, &(gateway_p->hd_addr), ETH_ALEN);
/* Pseudo IPv6 datagram for checksum calculation */
memset(&p_ip6, '\0', sizeof(struct pseudo_ip6_datagram));
p_ip6.hdr.p_ip6_src = sndip6_p->hdr.ip6_src;
p_ip6.hdr.p_ip6_dst = sndip6_p->hdr.ip6_dst;
p_ip6.hdr.p_ip6_plen = sndip6_p->hdr.ip6_plen;
p_ip6.hdr.p_ip6_zero1 = 0;
p_ip6.hdr.p_ip6_zero2 = 0;
p_ip6.hdr.p_ip6_nxt = sndip6_p->hdr.ip6_nxt;
memcpy(p_ip6.payload, sndna_p, sizeof(struct neighbor_adv));
/* Calculate checksum */
sndna_p->defs.nd_na_cksum = calc_checksum((u_int16_t *) (&p_ip6),
sizeof(struct pseudo_ip6_hdr)
+
sizeof(struct neighbor_adv));
/* Send Neighbor Advertisement reply */
retval = write(sd, &sndeth, sndeth_size);
if (retval != sndeth_size)
fatal_error("write()");
}
/*
* Function: return_arp_reply()
*
* Description:
* This function returns arp reply message to arp request message.
* And it updates the IPv4 gateway information.
*
* Argument:
* sd : socket to send arp reply message
* rcveth_p : pointer to ether frame data
* gateway_p : pointer to IPv4 gateway information
*
* Return value:
* None
*/
void
return_arp_reply(int sd, struct eth_frame *rcveth_p,
struct ip4_gateway_info *gateway_p)
{
int retval;
struct arp_datagram *rcvarp_p; /* ARP part of receiving frame */
unsigned char new_hd_addr[ETH_ALEN]; /* New MAC address */
unsigned char new_nexthop[4]; /* New next hop */
size_t sndeth_size; /* Size of sending frame */
struct eth_frame sndeth; /* sending frame */
struct arp_datagram *sndarp_p; /* ARP part of sending frame */
rcvarp_p = (struct arp_datagram *)&(rcveth_p->data);
/* If arp message is not arp request, do nothing */
if (debug)
fprintf(stderr, "ARP OP code is %02x\n",
ntohs(rcvarp_p->hdr.ar_op));
if (rcvarp_p->hdr.ar_op != htons(ARPOP_REQUEST))
return;
/* Update the gateway information */
memset(new_hd_addr, '\0', ETH_ALEN); /* MAC address */
for (;;) {
new_hd_addr[3] = rand_within(0, 254);
new_hd_addr[4] = rand_within(0, 254);
new_hd_addr[5] = rand_within(1, 254);
if (memcmp(gateway_p->hd_addr, new_hd_addr, ETH_ALEN)) {
memcpy(gateway_p->hd_addr, new_hd_addr, ETH_ALEN);
break;
}
}
memcpy(gateway_p->ip_addr, rcvarp_p->ar_tip, 4); /* IP address */
for (;;) { /* next hop */
memcpy(new_nexthop, gateway_p->ip_addr, 4);
new_nexthop[3] = rand_within(1, 254);
if (memcmp(gateway_p->nexthop, new_nexthop, 4)) {
memcpy(gateway_p->nexthop, new_nexthop, 4);
break;
}
}
/* Build a frame to send */
memset(&sndeth, '\0', sizeof(struct eth_frame));
sndarp_p = (struct arp_datagram *)&(sndeth.data);
sndeth_size = sizeof(struct ethhdr) + sizeof(struct arp_datagram);
/* Ether */
memcpy(sndeth.hdr.h_dest, rcveth_p->hdr.h_source, ETH_ALEN);
memcpy(sndeth.hdr.h_source, gateway_p->hd_addr, ETH_ALEN);
sndeth.hdr.h_proto = htons(ETH_P_ARP);
/* Arp */
sndarp_p->hdr.ar_hrd = htons(ARPHRD_ETHER);
sndarp_p->hdr.ar_pro = htons(ETH_P_IP);
sndarp_p->hdr.ar_hln = ETH_ALEN;
sndarp_p->hdr.ar_pln = 4;
sndarp_p->hdr.ar_op = htons(ARPOP_REPLY);
memcpy(sndarp_p->ar_sha, gateway_p->hd_addr, ETH_ALEN);
memcpy(sndarp_p->ar_sip, gateway_p->ip_addr, 4);
memcpy(sndarp_p->ar_tha, rcvarp_p->ar_sha, ETH_ALEN);
memcpy(sndarp_p->ar_tip, rcvarp_p->ar_sip, 4);
/* Send ARP reply */
retval = write(sd, &sndeth, sndeth_size);
if (retval != sndeth_size)
fatal_error("write()");
}
