void
handle_ether(const u_char * pkt, int len, void *userdata)
{
struct ether_header *e = (struct ether_header *)pkt;
unsigned short etype;
if (len < ETHER_HDR_LEN)
return;
etype = nptohs(&e->ether_type);
if (callback_ether)
if (0 != callback_ether(pkt, len, userdata))
return;
pkt += ETHER_HDR_LEN;
len -= ETHER_HDR_LEN;
if (ETHERTYPE_8021Q == etype) {
unsigned short vlan = nptohs((unsigned short *) pkt);
if (callback_vlan)
if (0 != callback_vlan(vlan, userdata))
return;
etype = nptohs((unsigned short *)(pkt + 2));
pkt += 4;
len -= 4;
}
if (len < 0)
return;
/* fprintf(stderr, "Ethernet packet of len %d ethertype %#04x\n", len, etype); */
if (is_ethertype_ip(etype)) {
handle_ip((struct ip *)pkt, len, userdata);
}
}
void
handle_loop(const u_char * pkt, int len, void *userdata)
{
unsigned int family = nptohl(pkt);
if (is_family_inet(family))
handle_ip((struct ip *)(pkt + 4), len - 4, userdata);
}
void sr_handlepacket(struct sr_instance* sr,
uint8_t * packet/* lent */,
unsigned int len,
char* interface/* lent */)
{
/* REQUIRES */
assert(sr);
assert(packet);
assert(interface);
printf("*** -> Received packet of length %d \n",len);
uint8_t *pkt = malloc(len);
memcpy(pkt, packet, len);
sr_ethernet_hdr_t *hdr = get_ethernet_hdr(pkt);
enum sr_ethertype type = ntohs(hdr->ether_type);
if (type == ethertype_arp) {
char *inf_cpy = malloc(sr_IFACE_NAMELEN);
memcpy(inf_cpy, interface, sr_IFACE_NAMELEN);
handle_arp(sr, pkt, inf_cpy, len);
} else if (type == ethertype_ip) {
handle_ip(sr, pkt, len);
} else {
fprintf(stderr, "invalid packet type id in ethernet header\n");
}
}/* end sr_ForwardPacket */
void
handle_ppp(const u_char * pkt, int len, void *userdata)
{
char buf[PCAP_SNAPLEN];
unsigned short proto;
if (len < 2)
return NULL;
if (*pkt == PPP_ADDRESS_VAL && *(pkt + 1) == PPP_CONTROL_VAL) {
pkt += 2; /* ACFC not used */
len -= 2;
}
if (len < 2)
return NULL;
if (*pkt % 2) {
proto = *pkt; /* PFC is used */
pkt++;
len--;
} else {
proto = nptohs(pkt);
pkt += 2;
len -= 2;
}
if (is_ethertype_ip(proto))
handle_ip((struct ip *)pkt, len, userdata);
}
void handle_ether(const struct timeval& t, WifipcapCallbacks *cbs, const u_char *ptr, int len)
{
ether_hdr_t hdr;
hdr.da = ether2MAC(ptr);
hdr.sa = ether2MAC(ptr+6);
hdr.type = EXTRACT_16BITS(ptr + 12);
ptr += 14;
len -= 14;
cbs->HandleEthernet(t, &hdr, ptr, len);
switch (hdr.type) {
case ETHERTYPE_IP:
handle_ip(t, cbs, ptr, len);
return;
case ETHERTYPE_IPV6:
handle_ip6(t, cbs, ptr, len);
return;
case ETHERTYPE_ARP:
handle_arp(t, cbs, ptr, len);
return;
default:
cbs->HandleL2Unknown(t, hdr.type, ptr, len);
return;
}
}
dns_message *
handle_ether(const u_char * pkt, int len)
{
char buf[PCAP_SNAPLEN];
struct ether_header *e = (void *) pkt;
unsigned short etype = ntohs(e->ether_type);
if (len < ETHER_HDR_LEN)
return NULL;
pkt += ETHER_HDR_LEN;
len -= ETHER_HDR_LEN;
if (ETHERTYPE_8021Q == etype) {
if (!match_vlan(pkt))
return NULL;
etype = ntohs(*(unsigned short *) (pkt + 2));
pkt += 4;
len -= 4;
}
if (len < 0)
return NULL;
if (is_ethertype_ip(etype)) {
memcpy(buf, pkt, len);
return handle_ip((struct ip *) buf, len);
}
return NULL;
}
dns_message *
handle_ppp(const u_char * pkt, int len)
{
char buf[PCAP_SNAPLEN];
unsigned short us;
unsigned short proto;
if (len < 2)
return NULL;
if (*pkt == PPP_ADDRESS_VAL && *(pkt + 1) == PPP_CONTROL_VAL) {
pkt += 2; /* ACFC not used */
len -= 2;
}
if (len < 2)
return NULL;
if (*pkt % 2) {
proto = *pkt; /* PFC is used */
pkt++;
len--;
} else {
memcpy(&us, pkt, sizeof(us));
proto = ntohs(us);
pkt += 2;
len -= 2;
}
if (is_ethertype_ip(proto)) {
memcpy(buf, pkt, len);
return handle_ip((struct ip *) buf, len);
}
return NULL;
}
dns_message *
handle_loop(const u_char * pkt, int len)
{
unsigned int family;
memcpy(&family, pkt, sizeof(family));
if (is_family_inet(family))
return handle_ip((struct ip *) (pkt + 4), len - 4);
return NULL;
}
void
handle_linux_sll(const u_char * pkt, int len, void *userdata)
{
struct sll_header *s = (struct sll_header *)pkt;
unsigned short etype, eproto;
if (len < SLL_HDR_LEN)
return;
etype = nptohs(&s->sll_pkttype);
if (etype == LINUX_SLL_BROADCAST || etype == LINUX_SLL_MULTICAST)
return;
eproto = nptohs(&s->sll_protocol);
if (eproto != ETHERTYPE_IP)
return;
pkt += SLL_HDR_LEN;
len -= SLL_HDR_LEN;
/* fprintf(stderr, "linnux cooked packet of len %d type %#04x proto %#04x\n", len, etype, eproto); */
handle_ip((struct ip *)pkt, len, userdata);
}
void
handle_gre(const u_char * gre, int len, void *userdata)
{
int grelen = 4;
unsigned short flags = nptohs(gre);
unsigned short etype = nptohs(gre + 2);
if (len < grelen)
return;
if (callback_gre)
callback_gre(gre, len, userdata);
if (flags & 0x0001) /* checksum present? */
grelen += 4;
if (flags & 0x0004) /* key present? */
grelen += 4;
if (flags & 0x0008) /* sequence number present? */
grelen += 4;
if (is_ethertype_ip(etype))
handle_ip((struct ip *) (gre + grelen), len - grelen, userdata);
}
static void read_packet(unsigned char* buf, uint16_t len) {
if (len < sizeof(struct ether_header)) {
lput_str("Ethernet header was too short");
return;
}
struct ether_header* eth = (struct ether_header*)buf;
if (memcmp(eth->dest, MAC_ADDRESS, ETHER_ADDR_LEN) != 0 &&
memcmp(eth->dest, BROADCAST_ADDRESS, ETHER_ADDR_LEN) != 0) {
lput_str("Ignoring packet not meant for me");
return;
}
uint16_t payload_len = len - sizeof(struct ether_header);
unsigned char* payload = (unsigned char*)(eth + 1);
ntohs(ð->type);
switch (eth->type) {
case ETHERTYPE_IP:
if (payload_len < sizeof(struct ip_header)) {
lput_str("IP header was too short");
return;
}
unsigned char* ip_payload = payload + sizeof(struct ip_header);
uint16_t ip_payload_len = payload_len - sizeof(struct ip_header);
handle_ip((struct ip_header*)payload, ip_payload, ip_payload_len);
break;
case ETHERTYPE_ARP:
if (payload_len < sizeof(struct arp_header)) {
lput_str("ARP header was too short");
return;
}
handle_arp((struct arp_header*)payload);
break;
default:
lput_str("Unknown ETHERTYPE:");
lput16_hex(eth->type);
lput_str("\r\n");
break;
}
}
int check_tun(const struct arguments *args,
const struct epoll_event *ev,
const int epoll_fd,
int sessions, int maxsessions) {
// Check tun error
if (ev->events & EPOLLERR) {
log_android(ANDROID_LOG_ERROR, "tun %d exception", args->tun);
if (fcntl(args->tun, F_GETFL) < 0) {
log_android(ANDROID_LOG_ERROR, "fcntl tun %d F_GETFL error %d: %s",
args->tun, errno, strerror(errno));
report_exit(args, "fcntl tun %d F_GETFL error %d: %s",
args->tun, errno, strerror(errno));
} else
report_exit(args, "tun %d exception", args->tun);
return -1;
}
// Check tun read
if (ev->events & EPOLLIN) {
uint8_t *buffer = malloc(get_mtu());
ssize_t length = read(args->tun, buffer, get_mtu());
if (length < 0) {
free(buffer);
log_android(ANDROID_LOG_ERROR, "tun %d read error %d: %s",
args->tun, errno, strerror(errno));
if (errno == EINTR || errno == EAGAIN)
// Retry later
return 0;
else {
report_exit(args, "tun %d read error %d: %s",
args->tun, errno, strerror(errno));
return -1;
}
}
else if (length > 0) {
// Write pcap record
if (pcap_file != NULL)
write_pcap_rec(buffer, (size_t) length);
if (length > max_tun_msg) {
max_tun_msg = length;
log_android(ANDROID_LOG_WARN, "Maximum tun msg length %d", max_tun_msg);
}
// Handle IP from tun
handle_ip(args, buffer, (size_t) length, epoll_fd, sessions, maxsessions);
free(buffer);
}
else {
// tun eof
free(buffer);
log_android(ANDROID_LOG_ERROR, "tun %d empty read", args->tun);
report_exit(args, "tun %d empty read", args->tun);
return -1;
}
}
return 0;
}
void
handle_raw(const u_char * pkt, int len, void *userdata)
{
handle_ip((struct ip *)pkt, len, userdata);
}
dns_message *
handle_raw(const u_char * pkt, int len)
{
return handle_ip((struct ip *) pkt, len);
}