net/netfilter/ipset/ip_set_getport.c

   1 /* Copyright (C) 2003-2011 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License version 2 as
   5  * published by the Free Software Foundation.
   6  */
   7
   8 /* Get Layer-4 data from the packets */
   9
  10 #include <linux/ip.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/icmp.h>
  13 #include <linux/icmpv6.h>
  14 #include <linux/netfilter_ipv6/ip6_tables.h>
  15 #include <net/ip.h>
  16
  17 #include <linux/netfilter/ipset/ip_set_getport.h>
  18
  19 /* We must handle non-linear skbs */
  20 static bool
  21 get_port(const struct sk_buff *skb, int protocol, unsigned int protooff,
  22          bool src, __be16 *port, u8 *proto)
  23 {
  24         switch (protocol) {
  25         case IPPROTO_TCP: {
  26                 struct tcphdr _tcph;
  27                 const struct tcphdr *th;
  28
  29                 th = skb_header_pointer(skb, protooff, sizeof(_tcph), &_tcph);
  30                 if (th == NULL)
  31                         /* No choice either */
  32                         return false;
  33
  34                 *port = src ? th->source : th->dest;
  35                 break;
  36         }
  37         case IPPROTO_UDP: {
  38                 struct udphdr _udph;
  39                 const struct udphdr *uh;
  40
  41                 uh = skb_header_pointer(skb, protooff, sizeof(_udph), &_udph);
  42                 if (uh == NULL)
  43                         /* No choice either */
  44                         return false;
  45
  46                 *port = src ? uh->source : uh->dest;
  47                 break;
  48         }
  49         case IPPROTO_ICMP: {
  50                 struct icmphdr _ich;
  51                 const struct icmphdr *ic;
  52
  53                 ic = skb_header_pointer(skb, protooff, sizeof(_ich), &_ich);
  54                 if (ic == NULL)
  55                         return false;
  56
  57                 *port = (__force __be16)htons((ic->type << 8) | ic->code);
  58                 break;
  59         }
  60         case IPPROTO_ICMPV6: {
  61                 struct icmp6hdr _ich;
  62                 const struct icmp6hdr *ic;
  63
  64                 ic = skb_header_pointer(skb, protooff, sizeof(_ich), &_ich);
  65                 if (ic == NULL)
  66                         return false;
  67
  68                 *port = (__force __be16)
  69                         htons((ic->icmp6_type << 8) | ic->icmp6_code);
  70                 break;
  71         }
  72         default:
  73                 break;
  74         }
  75         *proto = protocol;
  76
  77         return true;
  78 }
  79
  80 bool
  81 ip_set_get_ip4_port(const struct sk_buff *skb, bool src,
  82                     __be16 *port, u8 *proto)
  83 {
  84         const struct iphdr *iph = ip_hdr(skb);
  85         unsigned int protooff = ip_hdrlen(skb);
  86         int protocol = iph->protocol;
  87
  88         /* See comments at tcp_match in ip_tables.c */
  89         if (protocol <= 0 || (ntohs(iph->frag_off) & IP_OFFSET))
  90                 return false;
  91
  92         return get_port(skb, protocol, protooff, src, port, proto);
  93 }
  94 EXPORT_SYMBOL_GPL(ip_set_get_ip4_port);
  95
  96 bool
  97 ip_set_get_ip6_port(const struct sk_buff *skb, bool src,
  98                     __be16 *port, u8 *proto)
  99 {
 100         unsigned int protooff = 0;
 101         int protocol;
 102         unsigned short fragoff;
 103
 104         protocol = ipv6_find_hdr(skb, &protooff, -1, &fragoff);
 105         if (protocol <= 0 || fragoff)
 106                 return false;
 107
 108         return get_port(skb, protocol, protooff, src, port, proto);
 109 }
 110 EXPORT_SYMBOL_GPL(ip_set_get_ip6_port);
 111
 112 bool
 113 ip_set_get_ip_port(const struct sk_buff *skb, u8 pf, bool src, __be16 *port)
 114 {
 115         bool ret;
 116         u8 proto;
 117
 118         switch (pf) {
 119         case AF_INET:
 120                 ret = ip_set_get_ip4_port(skb, src, port, &proto);
 121                 break;
 122         case AF_INET6:
 123                 ret = ip_set_get_ip6_port(skb, src, port, &proto);
 124                 break;
 125         default:
 126                 return false;
 127         }
 128         if (!ret)
 129                 return ret;
 130         switch (proto) {
 131         case IPPROTO_TCP:
 132         case IPPROTO_UDP:
 133                 return true;
 134         default:
 135                 return false;
 136         }
 137 }
 138 EXPORT_SYMBOL_GPL(ip_set_get_ip_port);