ip_set_getport.c
/* Copyright (C) 2003-2011 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/* Get Layer-4 data from the packets */
#include <linux/ip.h>
#include <linux/skbuff.h>
#include <linux/icmp.h>
#include <linux/icmpv6.h>
#include <linux/sctp.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/netfilter/ipset/ip_set_getport.h>
#include <linux/export.h>
/* We must handle non-linear skbs */
static bool
get_port(const struct sk_buff *skb, int protocol, unsigned int protooff,
bool src, __be16 *port, u8 *proto)
{
switch (protocol) {
case IPPROTO_TCP: {
struct tcphdr _tcph;
const struct tcphdr *th;
th = skb_header_pointer(skb, protooff, sizeof(_tcph), &_tcph);
if (th == NULL)
/* No choice either */
return false;
*port = src ? th->source : th->dest;
break;
}
case IPPROTO_SCTP: {
sctp_sctphdr_t _sh;
const sctp_sctphdr_t *sh;
sh = skb_header_pointer(skb, protooff, sizeof(_sh), &_sh);
if (sh == NULL)
/* No choice either */
return false;
*port = src ? sh->source : sh->dest;
break;
}
case IPPROTO_UDP:
case IPPROTO_UDPLITE: {
struct udphdr _udph;
const struct udphdr *uh;
uh = skb_header_pointer(skb, protooff, sizeof(_udph), &_udph);
if (uh == NULL)
/* No choice either */
return false;
*port = src ? uh->source : uh->dest;
break;
}
case IPPROTO_ICMP: {
struct icmphdr _ich;
const struct icmphdr *ic;
ic = skb_header_pointer(skb, protooff, sizeof(_ich), &_ich);
if (ic == NULL)
return false;
*port = (__force __be16)htons((ic->type << 8) | ic->code);
break;
}
case IPPROTO_ICMPV6: {
struct icmp6hdr _ich;
const struct icmp6hdr *ic;
ic = skb_header_pointer(skb, protooff, sizeof(_ich), &_ich);
if (ic == NULL)
return false;
*port = (__force __be16)
htons((ic->icmp6_type << 8) | ic->icmp6_code);
break;
}
default:
break;
}
*proto = protocol;
return true;
}
bool
ip_set_get_ip4_port(const struct sk_buff *skb, bool src,
__be16 *port, u8 *proto)
{
const struct iphdr *iph = ip_hdr(skb);
unsigned int protooff = ip_hdrlen(skb);
int protocol = iph->protocol;
/* See comments at tcp_match in ip_tables.c */
if (protocol <= 0)
return false;
if (ntohs(iph->frag_off) & IP_OFFSET)
switch (protocol) {
case IPPROTO_TCP:
case IPPROTO_SCTP:
case IPPROTO_UDP:
case IPPROTO_UDPLITE:
case IPPROTO_ICMP:
/* Port info not available for fragment offset > 0 */
return false;
default:
/* Other protocols doesn't have ports,
so we can match fragments */
*proto = protocol;
return true;
}
return get_port(skb, protocol, protooff, src, port, proto);
}
EXPORT_SYMBOL_GPL(ip_set_get_ip4_port);
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
bool
ip_set_get_ip6_port(const struct sk_buff *skb, bool src,
__be16 *port, u8 *proto)
{
int protoff;
u8 nexthdr;
__be16 frag_off = 0;
nexthdr = ipv6_hdr(skb)->nexthdr;
protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
&frag_off);
if (protoff < 0 || (frag_off & htons(~0x7)) != 0)
return false;
return get_port(skb, nexthdr, protoff, src, port, proto);
}
EXPORT_SYMBOL_GPL(ip_set_get_ip6_port);
#endif
bool
ip_set_get_ip_port(const struct sk_buff *skb, u8 pf, bool src, __be16 *port)
{
bool ret;
u8 proto;
switch (pf) {
case NFPROTO_IPV4:
ret = ip_set_get_ip4_port(skb, src, port, &proto);
break;
case NFPROTO_IPV6:
ret = ip_set_get_ip6_port(skb, src, port, &proto);
break;
default:
return false;
}
if (!ret)
return ret;
switch (proto) {
case IPPROTO_TCP:
case IPPROTO_UDP:
return true;
default:
return false;
}
}
EXPORT_SYMBOL_GPL(ip_set_get_ip_port);