// Passes the received forward to the appropriate handler
void ethernet_recv_frame(char *buf, int len)
{
ethernet_header *head = (ethernet_header*)buf;
dprintf("received frame of length %d\n", len);
//printf("type: %02x%02x", head->ether_type[0], head->ether_type[1]);
//if ( memcmp(ethernet_opt_address, head->dest_addr, 6) != 0 )
// return;
// ARP
if ( head->ether_type[0] == 0x08 && head->ether_type[1] == 0x06 )
{
arp_recv(buf, len);
}
// IP
else if ( head->ether_type[0] == 0x08 && head->ether_type[1] == 0x00 )
{
// Pass over the IP packet without the ethernet header and checksum
ip_input(buf+sizeof(ethernet_header), len-sizeof(ethernet_header)-4);
}
}
static int arp_proc(struct netbuf *buf)
{
int ret = 0;
switch (buf->cmd) {
case ARP_CMD_MACADDR:
memcpy(my_macaddr, buf->option.common.macaddr.addr, MACADDR_SIZE);
break;
case ARP_CMD_IPADDR:
my_ipaddr = buf->option.common.ipaddr.addr;
break;
case ARP_CMD_RECV:
ret = arp_recv(buf);
break;
case ARP_CMD_SEND:
ret = arp_send(buf);
break;
default:
break;
}
return ret;
}
void *arp(char *ifname)
{
int sock,i;
struct sockaddr_ll ifs;
struct ifreq ifr;
pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL);
sock = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ARP));
if(sock == -1) {
fprintf(stderr, "Socket error %d.\n", errno);
exit(1);
}
/* Get the hwaddr and ifindex of the interface */
memset(ifr.ifr_name, 0, IFNAMSIZ);
strncpy(ifr.ifr_name, (char *) ifname, IFNAMSIZ);
if(ioctl(sock, SIOCGIFHWADDR, &ifr) < 0) {
syslog(LOG_ERR, "error: ioctl SIOCGIFHWADDR for %s: %s\n", (char *) ifname, strerror(errno));
abort();
}
memset(ifs.sll_addr, 0, ETH_ALEN);
memcpy(ifs.sll_addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
if(ioctl(sock, SIOCGIFINDEX, &ifr) < 0) {
syslog(LOG_ERR, "error: ioctl SIOCGIFINDEX for %s: %s", (char *) ifname, strerror(errno));
abort();
}
ifs.sll_family = AF_PACKET;
ifs.sll_protocol = htons(ETH_P_ARP);
ifs.sll_ifindex = ifr.ifr_ifindex;
ifs.sll_hatype = ARPHRD_ETHER;
ifs.sll_pkttype = PACKET_BROADCAST;
ifs.sll_halen = ETH_ALEN;
if(bind(sock, (struct sockaddr *)&ifs, sizeof(struct sockaddr_ll)) < 0) {
fprintf(stderr, "Bind %s: %d\n", (char *) ifname, errno);
abort();
}
while (1) {
ether_arp_frame frame;
unsigned long src;
unsigned long dst;
struct in_addr sia;
struct in_addr dia;
do {
pthread_testcancel();
/* Sleep a bit in order not to overload the system */
usleep(300);
if (arp_recv(sock, &frame) <= 0)
continue;
/* Insert all the replies into ARP table */
if (frame.arp.arp_op == ntohs(ARPOP_REPLY)) {
/* Received frame is an ARP reply */
struct arpreq k_arpreq;
int arpsock;
struct sockaddr_in *sin;
if ((arpsock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
syslog(LOG_ERR, "error: ARP socket for %s: %s", (char *) ifname, strerror(errno));
continue;
}
k_arpreq.arp_ha.sa_family = ARPHRD_ETHER;
memcpy(&k_arpreq.arp_ha.sa_data, &frame.arp.arp_sha, sizeof(frame.arp.arp_sha));
k_arpreq.arp_flags = ATF_COM;
if (option_arpperm)
k_arpreq.arp_flags = k_arpreq.arp_flags | ATF_PERM;
strncpy(k_arpreq.arp_dev, ifname, sizeof(k_arpreq.arp_dev));
k_arpreq.arp_pa.sa_family = AF_INET;
sin = (struct sockaddr_in *) &k_arpreq.arp_pa;
memcpy(&sin->sin_addr.s_addr, &frame.arp.arp_spa, sizeof(sin->sin_addr));
/* Update kernel ARP table with the data from reply */
if (debug)
printf("Received reply: updating kernel ARP table for %s(%s).\n", inet_ntoa(sin->sin_addr), (char *) ifname);
if (ioctl(arpsock, SIOCSARP, &k_arpreq) < 0) {
syslog(LOG_ERR, "error: ioctl SIOCSARP for %s(%s): %s", inet_ntoa(sin->sin_addr), (char *) ifname, strerror(errno));
close(arpsock);
continue;
}
close(arpsock);
/* Check if reply is for one of the requests in request queue */
rq_process(sin->sin_addr, ifs.sll_ifindex);
/* send gratuitous arp request to all other interfaces to let them
* update their ARP tables quickly */
for (i=0; i <= last_iface_idx; i++) {
if (strcmp(ifaces[i], ifname)) {
arp_req(ifaces[i], sin->sin_addr, 1);
}
}
}
} while (frame.arp.arp_op != htons(ARPOP_REQUEST));
/* Received frame is an ARP request */
memcpy(&src,(char *)frame.arp.arp_spa,4);
memcpy(&dst,(char *)frame.arp.arp_tpa,4);
dia.s_addr = dst;
sia.s_addr = src;
if (debug)
printf("Received ARP request for %s on iface %s\n", inet_ntoa(dia), (char *) ifname);
if (memcmp(&dia,&sia,sizeof(dia)) && dia.s_addr != 0) {
pthread_mutex_lock(&arptab_mutex);
/* Relay the ARP request to all other interfaces */
for (i=0; i <= last_iface_idx; i++) {
if (strcmp(ifaces[i], ifname)) {
arp_req(ifaces[i], dia, 0);
}
}
/* Add the request to the request queue */
if (debug)
printf("Adding %s to request queue\n", inet_ntoa(sia));
rq_add(&frame, &ifs);
pthread_mutex_unlock(&arptab_mutex);
}
}
}
