| /* |
| * ebt_ip |
| * |
| * Authors: |
| * Bart De Schuymer <bdschuym@pandora.be> |
| * |
| * April, 2002 |
| * |
| * Changes: |
| * added ip-sport and ip-dport |
| * Innominate Security Technologies AG <mhopf@innominate.com> |
| * September, 2002 |
| */ |
| #include <linux/ip.h> |
| #include <net/ip.h> |
| #include <linux/in.h> |
| #include <linux/module.h> |
| #include <linux/netfilter/x_tables.h> |
| #include <linux/netfilter_bridge/ebtables.h> |
| #include <linux/netfilter_bridge/ebt_ip.h> |
| |
| union pkthdr { |
| struct { |
| __be16 src; |
| __be16 dst; |
| } tcpudphdr; |
| struct { |
| u8 type; |
| u8 code; |
| } icmphdr; |
| struct { |
| u8 type; |
| } igmphdr; |
| }; |
| |
| static bool |
| ebt_ip_mt(const struct sk_buff *skb, struct xt_action_param *par) |
| { |
| const struct ebt_ip_info *info = par->matchinfo; |
| const struct iphdr *ih; |
| struct iphdr _iph; |
| const union pkthdr *pptr; |
| union pkthdr _pkthdr; |
| |
| ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph); |
| if (ih == NULL) |
| return false; |
| if ((info->bitmask & EBT_IP_TOS) && |
| NF_INVF(info, EBT_IP_TOS, info->tos != ih->tos)) |
| return false; |
| if ((info->bitmask & EBT_IP_SOURCE) && |
| NF_INVF(info, EBT_IP_SOURCE, |
| (ih->saddr & info->smsk) != info->saddr)) |
| return false; |
| if ((info->bitmask & EBT_IP_DEST) && |
| NF_INVF(info, EBT_IP_DEST, |
| (ih->daddr & info->dmsk) != info->daddr)) |
| return false; |
| if (info->bitmask & EBT_IP_PROTO) { |
| if (NF_INVF(info, EBT_IP_PROTO, info->protocol != ih->protocol)) |
| return false; |
| if (!(info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT | |
| EBT_IP_ICMP | EBT_IP_IGMP))) |
| return true; |
| if (ntohs(ih->frag_off) & IP_OFFSET) |
| return false; |
| |
| /* min icmp/igmp headersize is 4, so sizeof(_pkthdr) is ok. */ |
| pptr = skb_header_pointer(skb, ih->ihl*4, |
| sizeof(_pkthdr), &_pkthdr); |
| if (pptr == NULL) |
| return false; |
| if (info->bitmask & EBT_IP_DPORT) { |
| u32 dst = ntohs(pptr->tcpudphdr.dst); |
| if (NF_INVF(info, EBT_IP_DPORT, |
| dst < info->dport[0] || |
| dst > info->dport[1])) |
| return false; |
| } |
| if (info->bitmask & EBT_IP_SPORT) { |
| u32 src = ntohs(pptr->tcpudphdr.src); |
| if (NF_INVF(info, EBT_IP_SPORT, |
| src < info->sport[0] || |
| src > info->sport[1])) |
| return false; |
| } |
| if ((info->bitmask & EBT_IP_ICMP) && |
| NF_INVF(info, EBT_IP_ICMP, |
| pptr->icmphdr.type < info->icmp_type[0] || |
| pptr->icmphdr.type > info->icmp_type[1] || |
| pptr->icmphdr.code < info->icmp_code[0] || |
| pptr->icmphdr.code > info->icmp_code[1])) |
| return false; |
| if ((info->bitmask & EBT_IP_IGMP) && |
| NF_INVF(info, EBT_IP_IGMP, |
| pptr->igmphdr.type < info->igmp_type[0] || |
| pptr->igmphdr.type > info->igmp_type[1])) |
| return false; |
| } |
| return true; |
| } |
| |
| static int ebt_ip_mt_check(const struct xt_mtchk_param *par) |
| { |
| const struct ebt_ip_info *info = par->matchinfo; |
| const struct ebt_entry *e = par->entryinfo; |
| |
| if (e->ethproto != htons(ETH_P_IP) || |
| e->invflags & EBT_IPROTO) |
| return -EINVAL; |
| if (info->bitmask & ~EBT_IP_MASK || info->invflags & ~EBT_IP_MASK) |
| return -EINVAL; |
| if (info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT)) { |
| if (info->invflags & EBT_IP_PROTO) |
| return -EINVAL; |
| if (info->protocol != IPPROTO_TCP && |
| info->protocol != IPPROTO_UDP && |
| info->protocol != IPPROTO_UDPLITE && |
| info->protocol != IPPROTO_SCTP && |
| info->protocol != IPPROTO_DCCP) |
| return -EINVAL; |
| } |
| if (info->bitmask & EBT_IP_DPORT && info->dport[0] > info->dport[1]) |
| return -EINVAL; |
| if (info->bitmask & EBT_IP_SPORT && info->sport[0] > info->sport[1]) |
| return -EINVAL; |
| if (info->bitmask & EBT_IP_ICMP) { |
| if ((info->invflags & EBT_IP_PROTO) || |
| info->protocol != IPPROTO_ICMP) |
| return -EINVAL; |
| if (info->icmp_type[0] > info->icmp_type[1] || |
| info->icmp_code[0] > info->icmp_code[1]) |
| return -EINVAL; |
| } |
| if (info->bitmask & EBT_IP_IGMP) { |
| if ((info->invflags & EBT_IP_PROTO) || |
| info->protocol != IPPROTO_IGMP) |
| return -EINVAL; |
| if (info->igmp_type[0] > info->igmp_type[1]) |
| return -EINVAL; |
| } |
| return 0; |
| } |
| |
| static struct xt_match ebt_ip_mt_reg __read_mostly = { |
| .name = "ip", |
| .revision = 0, |
| .family = NFPROTO_BRIDGE, |
| .match = ebt_ip_mt, |
| .checkentry = ebt_ip_mt_check, |
| .matchsize = sizeof(struct ebt_ip_info), |
| .me = THIS_MODULE, |
| }; |
| |
| static int __init ebt_ip_init(void) |
| { |
| return xt_register_match(&ebt_ip_mt_reg); |
| } |
| |
| static void __exit ebt_ip_fini(void) |
| { |
| xt_unregister_match(&ebt_ip_mt_reg); |
| } |
| |
| module_init(ebt_ip_init); |
| module_exit(ebt_ip_fini); |
| MODULE_DESCRIPTION("Ebtables: IPv4 protocol packet match"); |
| MODULE_LICENSE("GPL"); |