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/sctp.h> 15 #include <linux/netfilter_ipv6/ip6_tables.h> 16 #include <net/ip.h> 17 #include <net/ipv6.h> 18 19 #include <linux/netfilter/ipset/ip_set_getport.h> 20 #include <linux/export.h> 21 22 /* We must handle non-linear skbs */ 23 static bool 24 get_port(const struct sk_buff *skb, int protocol, unsigned int protooff, 25 bool src, __be16 *port, u8 *proto) 26 { 27 switch (protocol) { 28 case IPPROTO_TCP: { 29 struct tcphdr _tcph; 30 const struct tcphdr *th; 31 32 th = skb_header_pointer(skb, protooff, sizeof(_tcph), &_tcph); 33 if (!th) 34 /* No choice either */ 35 return false; 36 37 *port = src ? th->source : th->dest; 38 break; 39 } 40 case IPPROTO_SCTP: { 41 sctp_sctphdr_t _sh; 42 const sctp_sctphdr_t *sh; 43 44 sh = skb_header_pointer(skb, protooff, sizeof(_sh), &_sh); 45 if (!sh) 46 /* No choice either */ 47 return false; 48 49 *port = src ? sh->source : sh->dest; 50 break; 51 } 52 case IPPROTO_UDP: 53 case IPPROTO_UDPLITE: { 54 struct udphdr _udph; 55 const struct udphdr *uh; 56 57 uh = skb_header_pointer(skb, protooff, sizeof(_udph), &_udph); 58 if (!uh) 59 /* No choice either */ 60 return false; 61 62 *port = src ? uh->source : uh->dest; 63 break; 64 } 65 case IPPROTO_ICMP: { 66 struct icmphdr _ich; 67 const struct icmphdr *ic; 68 69 ic = skb_header_pointer(skb, protooff, sizeof(_ich), &_ich); 70 if (!ic) 71 return false; 72 73 *port = (__force __be16)htons((ic->type << 8) | ic->code); 74 break; 75 } 76 case IPPROTO_ICMPV6: { 77 struct icmp6hdr _ich; 78 const struct icmp6hdr *ic; 79 80 ic = skb_header_pointer(skb, protooff, sizeof(_ich), &_ich); 81 if (!ic) 82 return false; 83 84 *port = (__force __be16) 85 htons((ic->icmp6_type << 8) | ic->icmp6_code); 86 break; 87 } 88 default: 89 break; 90 } 91 *proto = protocol; 92 93 return true; 94 } 95 96 bool 97 ip_set_get_ip4_port(const struct sk_buff *skb, bool src, 98 __be16 *port, u8 *proto) 99 { 100 const struct iphdr *iph = ip_hdr(skb); 101 unsigned int protooff = skb_network_offset(skb) + ip_hdrlen(skb); 102 int protocol = iph->protocol; 103 104 /* See comments at tcp_match in ip_tables.c */ 105 if (protocol <= 0) 106 return false; 107 108 if (ntohs(iph->frag_off) & IP_OFFSET) 109 switch (protocol) { 110 case IPPROTO_TCP: 111 case IPPROTO_SCTP: 112 case IPPROTO_UDP: 113 case IPPROTO_UDPLITE: 114 case IPPROTO_ICMP: 115 /* Port info not available for fragment offset > 0 */ 116 return false; 117 default: 118 /* Other protocols doesn't have ports, 119 * so we can match fragments. 120 */ 121 *proto = protocol; 122 return true; 123 } 124 125 return get_port(skb, protocol, protooff, src, port, proto); 126 } 127 EXPORT_SYMBOL_GPL(ip_set_get_ip4_port); 128 129 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 130 bool 131 ip_set_get_ip6_port(const struct sk_buff *skb, bool src, 132 __be16 *port, u8 *proto) 133 { 134 int protoff; 135 u8 nexthdr; 136 __be16 frag_off = 0; 137 138 nexthdr = ipv6_hdr(skb)->nexthdr; 139 protoff = ipv6_skip_exthdr(skb, 140 skb_network_offset(skb) + 141 sizeof(struct ipv6hdr), &nexthdr, 142 &frag_off); 143 if (protoff < 0 || (frag_off & htons(~0x7)) != 0) 144 return false; 145 146 return get_port(skb, nexthdr, protoff, src, port, proto); 147 } 148 EXPORT_SYMBOL_GPL(ip_set_get_ip6_port); 149 #endif 150 151 bool 152 ip_set_get_ip_port(const struct sk_buff *skb, u8 pf, bool src, __be16 *port) 153 { 154 bool ret; 155 u8 proto; 156 157 switch (pf) { 158 case NFPROTO_IPV4: 159 ret = ip_set_get_ip4_port(skb, src, port, &proto); 160 break; 161 case NFPROTO_IPV6: 162 ret = ip_set_get_ip6_port(skb, src, port, &proto); 163 break; 164 default: 165 return false; 166 } 167 if (!ret) 168 return ret; 169 switch (proto) { 170 case IPPROTO_TCP: 171 case IPPROTO_UDP: 172 return true; 173 default: 174 return false; 175 } 176 } 177 EXPORT_SYMBOL_GPL(ip_set_get_ip_port); 178