From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- net/netfilter/xt_HMARK.c | 372 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 372 insertions(+) create mode 100644 net/netfilter/xt_HMARK.c (limited to 'net/netfilter/xt_HMARK.c') diff --git a/net/netfilter/xt_HMARK.c b/net/netfilter/xt_HMARK.c new file mode 100644 index 000000000..02afaf48a --- /dev/null +++ b/net/netfilter/xt_HMARK.c @@ -0,0 +1,372 @@ +/* + * xt_HMARK - Netfilter module to set mark by means of hashing + * + * (C) 2012 by Hans Schillstrom + * (C) 2012 by Pablo Neira Ayuso + * + * 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. + */ + +#include +#include +#include + +#include +#include + +#include +#if IS_ENABLED(CONFIG_NF_CONNTRACK) +#include +#endif +#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) +#include +#include +#endif + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Hans Schillstrom "); +MODULE_DESCRIPTION("Xtables: packet marking using hash calculation"); +MODULE_ALIAS("ipt_HMARK"); +MODULE_ALIAS("ip6t_HMARK"); + +struct hmark_tuple { + __be32 src; + __be32 dst; + union hmark_ports uports; + u8 proto; +}; + +static inline __be32 hmark_addr6_mask(const __be32 *addr32, const __be32 *mask) +{ + return (addr32[0] & mask[0]) ^ + (addr32[1] & mask[1]) ^ + (addr32[2] & mask[2]) ^ + (addr32[3] & mask[3]); +} + +static inline __be32 +hmark_addr_mask(int l3num, const __be32 *addr32, const __be32 *mask) +{ + switch (l3num) { + case AF_INET: + return *addr32 & *mask; + case AF_INET6: + return hmark_addr6_mask(addr32, mask); + } + return 0; +} + +static inline void hmark_swap_ports(union hmark_ports *uports, + const struct xt_hmark_info *info) +{ + union hmark_ports hp; + u16 src, dst; + + hp.b32 = (uports->b32 & info->port_mask.b32) | info->port_set.b32; + src = ntohs(hp.b16.src); + dst = ntohs(hp.b16.dst); + + if (dst > src) + uports->v32 = (dst << 16) | src; + else + uports->v32 = (src << 16) | dst; +} + +static int +hmark_ct_set_htuple(const struct sk_buff *skb, struct hmark_tuple *t, + const struct xt_hmark_info *info) +{ +#if IS_ENABLED(CONFIG_NF_CONNTRACK) + enum ip_conntrack_info ctinfo; + struct nf_conn *ct = nf_ct_get(skb, &ctinfo); + struct nf_conntrack_tuple *otuple; + struct nf_conntrack_tuple *rtuple; + + if (ct == NULL || nf_ct_is_untracked(ct)) + return -1; + + otuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; + rtuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple; + + t->src = hmark_addr_mask(otuple->src.l3num, otuple->src.u3.ip6, + info->src_mask.ip6); + t->dst = hmark_addr_mask(otuple->src.l3num, rtuple->src.u3.ip6, + info->dst_mask.ip6); + + if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) + return 0; + + t->proto = nf_ct_protonum(ct); + if (t->proto != IPPROTO_ICMP) { + t->uports.b16.src = otuple->src.u.all; + t->uports.b16.dst = rtuple->src.u.all; + hmark_swap_ports(&t->uports, info); + } + + return 0; +#else + return -1; +#endif +} + +/* This hash function is endian independent, to ensure consistent hashing if + * the cluster is composed of big and little endian systems. */ +static inline u32 +hmark_hash(struct hmark_tuple *t, const struct xt_hmark_info *info) +{ + u32 hash; + u32 src = ntohl(t->src); + u32 dst = ntohl(t->dst); + + if (dst < src) + swap(src, dst); + + hash = jhash_3words(src, dst, t->uports.v32, info->hashrnd); + hash = hash ^ (t->proto & info->proto_mask); + + return reciprocal_scale(hash, info->hmodulus) + info->hoffset; +} + +static void +hmark_set_tuple_ports(const struct sk_buff *skb, unsigned int nhoff, + struct hmark_tuple *t, const struct xt_hmark_info *info) +{ + int protoff; + + protoff = proto_ports_offset(t->proto); + if (protoff < 0) + return; + + nhoff += protoff; + if (skb_copy_bits(skb, nhoff, &t->uports, sizeof(t->uports)) < 0) + return; + + hmark_swap_ports(&t->uports, info); +} + +#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) +static int get_inner6_hdr(const struct sk_buff *skb, int *offset) +{ + struct icmp6hdr *icmp6h, _ih6; + + icmp6h = skb_header_pointer(skb, *offset, sizeof(_ih6), &_ih6); + if (icmp6h == NULL) + return 0; + + if (icmp6h->icmp6_type && icmp6h->icmp6_type < 128) { + *offset += sizeof(struct icmp6hdr); + return 1; + } + return 0; +} + +static int +hmark_pkt_set_htuple_ipv6(const struct sk_buff *skb, struct hmark_tuple *t, + const struct xt_hmark_info *info) +{ + struct ipv6hdr *ip6, _ip6; + int flag = IP6_FH_F_AUTH; + unsigned int nhoff = 0; + u16 fragoff = 0; + int nexthdr; + + ip6 = (struct ipv6hdr *) (skb->data + skb_network_offset(skb)); + nexthdr = ipv6_find_hdr(skb, &nhoff, -1, &fragoff, &flag); + if (nexthdr < 0) + return 0; + /* No need to check for icmp errors on fragments */ + if ((flag & IP6_FH_F_FRAG) || (nexthdr != IPPROTO_ICMPV6)) + goto noicmp; + /* Use inner header in case of ICMP errors */ + if (get_inner6_hdr(skb, &nhoff)) { + ip6 = skb_header_pointer(skb, nhoff, sizeof(_ip6), &_ip6); + if (ip6 == NULL) + return -1; + /* If AH present, use SPI like in ESP. */ + flag = IP6_FH_F_AUTH; + nexthdr = ipv6_find_hdr(skb, &nhoff, -1, &fragoff, &flag); + if (nexthdr < 0) + return -1; + } +noicmp: + t->src = hmark_addr6_mask(ip6->saddr.s6_addr32, info->src_mask.ip6); + t->dst = hmark_addr6_mask(ip6->daddr.s6_addr32, info->dst_mask.ip6); + + if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) + return 0; + + t->proto = nexthdr; + if (t->proto == IPPROTO_ICMPV6) + return 0; + + if (flag & IP6_FH_F_FRAG) + return 0; + + hmark_set_tuple_ports(skb, nhoff, t, info); + return 0; +} + +static unsigned int +hmark_tg_v6(struct sk_buff *skb, const struct xt_action_param *par) +{ + const struct xt_hmark_info *info = par->targinfo; + struct hmark_tuple t; + + memset(&t, 0, sizeof(struct hmark_tuple)); + + if (info->flags & XT_HMARK_FLAG(XT_HMARK_CT)) { + if (hmark_ct_set_htuple(skb, &t, info) < 0) + return XT_CONTINUE; + } else { + if (hmark_pkt_set_htuple_ipv6(skb, &t, info) < 0) + return XT_CONTINUE; + } + + skb->mark = hmark_hash(&t, info); + return XT_CONTINUE; +} +#endif + +static int get_inner_hdr(const struct sk_buff *skb, int iphsz, int *nhoff) +{ + const struct icmphdr *icmph; + struct icmphdr _ih; + + /* Not enough header? */ + icmph = skb_header_pointer(skb, *nhoff + iphsz, sizeof(_ih), &_ih); + if (icmph == NULL || icmph->type > NR_ICMP_TYPES) + return 0; + + /* Error message? */ + if (icmph->type != ICMP_DEST_UNREACH && + icmph->type != ICMP_SOURCE_QUENCH && + icmph->type != ICMP_TIME_EXCEEDED && + icmph->type != ICMP_PARAMETERPROB && + icmph->type != ICMP_REDIRECT) + return 0; + + *nhoff += iphsz + sizeof(_ih); + return 1; +} + +static int +hmark_pkt_set_htuple_ipv4(const struct sk_buff *skb, struct hmark_tuple *t, + const struct xt_hmark_info *info) +{ + struct iphdr *ip, _ip; + int nhoff = skb_network_offset(skb); + + ip = (struct iphdr *) (skb->data + nhoff); + if (ip->protocol == IPPROTO_ICMP) { + /* Use inner header in case of ICMP errors */ + if (get_inner_hdr(skb, ip->ihl * 4, &nhoff)) { + ip = skb_header_pointer(skb, nhoff, sizeof(_ip), &_ip); + if (ip == NULL) + return -1; + } + } + + t->src = ip->saddr & info->src_mask.ip; + t->dst = ip->daddr & info->dst_mask.ip; + + if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3)) + return 0; + + t->proto = ip->protocol; + + /* ICMP has no ports, skip */ + if (t->proto == IPPROTO_ICMP) + return 0; + + /* follow-up fragments don't contain ports, skip all fragments */ + if (ip->frag_off & htons(IP_MF | IP_OFFSET)) + return 0; + + hmark_set_tuple_ports(skb, (ip->ihl * 4) + nhoff, t, info); + + return 0; +} + +static unsigned int +hmark_tg_v4(struct sk_buff *skb, const struct xt_action_param *par) +{ + const struct xt_hmark_info *info = par->targinfo; + struct hmark_tuple t; + + memset(&t, 0, sizeof(struct hmark_tuple)); + + if (info->flags & XT_HMARK_FLAG(XT_HMARK_CT)) { + if (hmark_ct_set_htuple(skb, &t, info) < 0) + return XT_CONTINUE; + } else { + if (hmark_pkt_set_htuple_ipv4(skb, &t, info) < 0) + return XT_CONTINUE; + } + + skb->mark = hmark_hash(&t, info); + return XT_CONTINUE; +} + +static int hmark_tg_check(const struct xt_tgchk_param *par) +{ + const struct xt_hmark_info *info = par->targinfo; + + if (!info->hmodulus) { + pr_info("xt_HMARK: hash modulus can't be zero\n"); + return -EINVAL; + } + if (info->proto_mask && + (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3))) { + pr_info("xt_HMARK: proto mask must be zero with L3 mode\n"); + return -EINVAL; + } + if (info->flags & XT_HMARK_FLAG(XT_HMARK_SPI_MASK) && + (info->flags & (XT_HMARK_FLAG(XT_HMARK_SPORT_MASK) | + XT_HMARK_FLAG(XT_HMARK_DPORT_MASK)))) { + pr_info("xt_HMARK: spi-mask and port-mask can't be combined\n"); + return -EINVAL; + } + if (info->flags & XT_HMARK_FLAG(XT_HMARK_SPI) && + (info->flags & (XT_HMARK_FLAG(XT_HMARK_SPORT) | + XT_HMARK_FLAG(XT_HMARK_DPORT)))) { + pr_info("xt_HMARK: spi-set and port-set can't be combined\n"); + return -EINVAL; + } + return 0; +} + +static struct xt_target hmark_tg_reg[] __read_mostly = { + { + .name = "HMARK", + .family = NFPROTO_IPV4, + .target = hmark_tg_v4, + .targetsize = sizeof(struct xt_hmark_info), + .checkentry = hmark_tg_check, + .me = THIS_MODULE, + }, +#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) + { + .name = "HMARK", + .family = NFPROTO_IPV6, + .target = hmark_tg_v6, + .targetsize = sizeof(struct xt_hmark_info), + .checkentry = hmark_tg_check, + .me = THIS_MODULE, + }, +#endif +}; + +static int __init hmark_tg_init(void) +{ + return xt_register_targets(hmark_tg_reg, ARRAY_SIZE(hmark_tg_reg)); +} + +static void __exit hmark_tg_exit(void) +{ + xt_unregister_targets(hmark_tg_reg, ARRAY_SIZE(hmark_tg_reg)); +} + +module_init(hmark_tg_init); +module_exit(hmark_tg_exit); -- cgit v1.2.3-54-g00ecf