/**
* Extracts relevant data from "skb" and stores it in the "tuple" tuple.
*
* @param skb packet the data will be extracted from.
* @param tuple this function will populate this value using "skb"'s contents.
* @return whether packet processing should continue.
*/
verdict determine_in_tuple(struct sk_buff *skb, struct tuple *in_tuple)
{
struct icmphdr *icmp4;
struct icmp6hdr *icmp6;
verdict result = VER_CONTINUE;
log_debug("Step 1: Determining the Incoming Tuple");
switch (skb_l3_proto(skb)) {
case L3PROTO_IPV4:
switch (skb_l4_proto(skb)) {
case L4PROTO_UDP:
result = ipv4_udp(skb, in_tuple);
break;
case L4PROTO_TCP:
result = ipv4_tcp(skb, in_tuple);
break;
case L4PROTO_ICMP:
icmp4 = icmp_hdr(skb);
if (is_icmp4_info(icmp4->type)) {
result = ipv4_icmp_info(skb, in_tuple);
} else if (is_icmp4_error(icmp4->type)) {
result = ipv4_icmp_err(skb, in_tuple);
} else {
log_debug("Unknown ICMPv4 type: %u. Dropping packet...", icmp4->type);
inc_stats(skb, IPSTATS_MIB_INHDRERRORS);
result = VER_DROP;
}
break;
}
break;
case L3PROTO_IPV6:
switch (skb_l4_proto(skb)) {
case L4PROTO_UDP:
result = ipv6_udp(skb, in_tuple);
break;
case L4PROTO_TCP:
result = ipv6_tcp(skb, in_tuple);
break;
case L4PROTO_ICMP:
icmp6 = icmp6_hdr(skb);
if (is_icmp6_info(icmp6->icmp6_type)) {
result = ipv6_icmp_info(skb, in_tuple);
} else if (is_icmp6_error(icmp6->icmp6_type)) {
result = ipv6_icmp_err(skb, in_tuple);
} else {
log_debug("Unknown ICMPv6 type: %u. Dropping packet...", icmp6->icmp6_type);
inc_stats(skb, IPSTATS_MIB_INHDRERRORS);
result = VER_DROP;
}
break;
}
break;
}
/*
* We moved the transport-protocol-not-recognized ICMP errors to packet.c because they're
* covered in validations.
*/
log_tuple(in_tuple);
log_debug("Done step 1.");
return result;
}
bool determine_in_tuple(struct sk_buff *skb, struct tuple *tuple)
{
struct iphdr *hdr4;
struct ipv6hdr *hdr6;
struct icmphdr *icmp4;
struct icmp6hdr *icmp6;
struct hdr_iterator iterator;
log_debug("Step 1: Determining the Incoming Tuple");
switch (be16_to_cpu(skb->protocol)) {
case ETH_P_IP:
hdr4 = ip_hdr(skb);
switch (hdr4->protocol) {
case IPPROTO_UDP:
if (!ipv4_udp(hdr4, ipv4_extract_l4_hdr(hdr4), tuple))
return false;
break;
case IPPROTO_TCP:
if (!ipv4_tcp(hdr4, ipv4_extract_l4_hdr(hdr4), tuple))
return false;
break;
case IPPROTO_ICMP:
icmp4 = ipv4_extract_l4_hdr(hdr4);
if (is_icmp4_info(icmp4->type)) {
if (!ipv4_icmp_info(hdr4, icmp4, tuple))
return false;
} else {
if (!ipv4_icmp_err(hdr4, icmp4, tuple))
return false;
}
break;
default:
log_info("Unsupported transport protocol for IPv4: %d.", hdr4->protocol);
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PROT_UNREACH, 0);
return false;
}
break;
case ETH_P_IPV6:
hdr6 = ipv6_hdr(skb);
hdr_iterator_init(&iterator, hdr6);
hdr_iterator_last(&iterator);
switch (iterator.hdr_type) {
case IPPROTO_UDP:
if (!ipv6_udp(hdr6, iterator.data, tuple))
return false;
break;
case IPPROTO_TCP:
if (!ipv6_tcp(hdr6, iterator.data, tuple))
return false;
break;
case IPPROTO_ICMPV6:
icmp6 = iterator.data;
if (is_icmp6_info(icmp6->icmp6_type)) {
if (!ipv6_icmp_info(hdr6, icmp6, tuple))
return false;
} else {
if (!ipv6_icmp_err(hdr6, icmp6, tuple))
return false;
}
break;
default:
log_info("Unsupported transport protocol for IPv6: %d.", iterator.hdr_type);
icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
return false;
}
break;
default:
log_info("Packet's protocol (%d) is not IPv4 or IPv6.", be16_to_cpu(skb->protocol));
return false;
}
log_tuple(tuple);
log_debug("Done step 1.");
return true;
}
/**
* Extracts relevant data from "frag" and stores it in the "tuple" tuple.
*
* @param frag fragment the data will be extracted from. Whether the packet is fragmented or not,
* this has to be the chunk whose fragment offset is zero.
* @param tuple this function will populate this value using "frag"'s contents.
* @return whether packet processing should continue.
*/
verdict determine_in_tuple(struct fragment *frag, struct tuple *tuple)
{
struct iphdr *hdr4;
struct ipv6hdr *hdr6;
struct icmphdr *icmp4;
struct icmp6hdr *icmp6;
verdict result = VER_CONTINUE;
log_debug("Step 1: Determining the Incoming Tuple");
switch (frag->l3_hdr.proto) {
case L3PROTO_IPV4:
hdr4 = frag_get_ipv4_hdr(frag);
switch (frag->l4_hdr.proto) {
case L4PROTO_UDP:
result = ipv4_udp(hdr4, frag_get_udp_hdr(frag), tuple);
break;
case L4PROTO_TCP:
result = ipv4_tcp(hdr4, frag_get_tcp_hdr(frag), tuple);
break;
case L4PROTO_ICMP:
icmp4 = frag_get_icmp4_hdr(frag);
if (is_icmp4_info(icmp4->type)) {
result = ipv4_icmp_info(hdr4, icmp4, tuple);
} else if (is_icmp4_error(icmp4->type)) {
result = ipv4_icmp_err(hdr4, icmp4, tuple);
} else {
log_warning("Unknown ICMPv4 type: %u. Dropping packet...", icmp4->type);
result = VER_DROP;
}
break;
case L4PROTO_NONE:
log_crit(ERR_ILLEGAL_NONE, "IPv4 - First fragment has no transport header.");
result = VER_DROP;
}
break;
case L3PROTO_IPV6:
hdr6 = frag_get_ipv6_hdr(frag);
switch (frag->l4_hdr.proto) {
case L4PROTO_UDP:
result = ipv6_udp(hdr6, frag_get_udp_hdr(frag), tuple);
break;
case L4PROTO_TCP:
result = ipv6_tcp(hdr6, frag_get_tcp_hdr(frag), tuple);
break;
case L4PROTO_ICMP:
icmp6 = frag_get_icmp6_hdr(frag);
if (is_icmp6_info(icmp6->icmp6_type)) {
result = ipv6_icmp_info(hdr6, icmp6, tuple);
} else if (is_icmp6_error(icmp6->icmp6_type)) {
result = ipv6_icmp_err(hdr6, icmp6, tuple);
} else {
log_warning("Unknown ICMPv6 type: %u. Dropping packet...", icmp6->icmp6_type);
result = VER_DROP;
}
break;
case L4PROTO_NONE:
log_crit(ERR_ILLEGAL_NONE, "IPv6 - First fragment has no transport header.");
result = VER_DROP;
}
break;
}
/*
* We moved the transport-protocol-not-recognized ICMP errors to fragment_db because they're
* covered in validations.
*/
log_tuple(tuple);
log_debug("Done step 1.");
return result;
}
