diff options
Diffstat (limited to 'net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c')
| -rw-r--r-- | net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c new file mode 100644 index 00000000..4111050a --- /dev/null +++ b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c @@ -0,0 +1,398 @@ +/* + * Copyright (C)2004 USAGI/WIDE Project + * + * 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. + * + * Author: + * Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp> + */ + +#include <linux/types.h> +#include <linux/ipv6.h> +#include <linux/in6.h> +#include <linux/netfilter.h> +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/icmp.h> +#include <net/ipv6.h> +#include <net/inet_frag.h> + +#include <linux/netfilter_bridge.h> +#include <linux/netfilter_ipv6.h> +#include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_helper.h> +#include <net/netfilter/nf_conntrack_l4proto.h> +#include <net/netfilter/nf_conntrack_l3proto.h> +#include <net/netfilter/nf_conntrack_core.h> +#include <net/netfilter/nf_conntrack_zones.h> +#include <net/netfilter/ipv6/nf_conntrack_ipv6.h> +#include <net/netfilter/ipv6/nf_defrag_ipv6.h> +#include <net/netfilter/nf_log.h> + +static bool ipv6_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff, + struct nf_conntrack_tuple *tuple) +{ + const u_int32_t *ap; + u_int32_t _addrs[8]; + + ap = skb_header_pointer(skb, nhoff + offsetof(struct ipv6hdr, saddr), + sizeof(_addrs), _addrs); + if (ap == NULL) + return false; + + memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6)); + memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6)); + + return true; +} + +static bool ipv6_invert_tuple(struct nf_conntrack_tuple *tuple, + const struct nf_conntrack_tuple *orig) +{ + memcpy(tuple->src.u3.ip6, orig->dst.u3.ip6, sizeof(tuple->src.u3.ip6)); + memcpy(tuple->dst.u3.ip6, orig->src.u3.ip6, sizeof(tuple->dst.u3.ip6)); + + return true; +} + +static int ipv6_print_tuple(struct seq_file *s, + const struct nf_conntrack_tuple *tuple) +{ + return seq_printf(s, "src=%pI6 dst=%pI6 ", + tuple->src.u3.ip6, tuple->dst.u3.ip6); +} + +/* + * Based on ipv6_skip_exthdr() in net/ipv6/exthdr.c + * + * This function parses (probably truncated) exthdr set "hdr" + * of length "len". "nexthdrp" initially points to some place, + * where type of the first header can be found. + * + * It skips all well-known exthdrs, and returns pointer to the start + * of unparsable area i.e. the first header with unknown type. + * if success, *nexthdr is updated by type/protocol of this header. + * + * NOTES: - it may return pointer pointing beyond end of packet, + * if the last recognized header is truncated in the middle. + * - if packet is truncated, so that all parsed headers are skipped, + * it returns -1. + * - if packet is fragmented, return pointer of the fragment header. + * - ESP is unparsable for now and considered like + * normal payload protocol. + * - Note also special handling of AUTH header. Thanks to IPsec wizards. + */ + +static int nf_ct_ipv6_skip_exthdr(const struct sk_buff *skb, int start, + u8 *nexthdrp, int len) +{ + u8 nexthdr = *nexthdrp; + + while (ipv6_ext_hdr(nexthdr)) { + struct ipv6_opt_hdr hdr; + int hdrlen; + + if (len < (int)sizeof(struct ipv6_opt_hdr)) + return -1; + if (nexthdr == NEXTHDR_NONE) + break; + if (nexthdr == NEXTHDR_FRAGMENT) + break; + if (skb_copy_bits(skb, start, &hdr, sizeof(hdr))) + BUG(); + if (nexthdr == NEXTHDR_AUTH) + hdrlen = (hdr.hdrlen+2)<<2; + else + hdrlen = ipv6_optlen(&hdr); + + nexthdr = hdr.nexthdr; + len -= hdrlen; + start += hdrlen; + } + + *nexthdrp = nexthdr; + return start; +} + +static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff, + unsigned int *dataoff, u_int8_t *protonum) +{ + unsigned int extoff = nhoff + sizeof(struct ipv6hdr); + unsigned char pnum; + int protoff; + + if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr), + &pnum, sizeof(pnum)) != 0) { + pr_debug("ip6_conntrack_core: can't get nexthdr\n"); + return -NF_ACCEPT; + } + protoff = nf_ct_ipv6_skip_exthdr(skb, extoff, &pnum, skb->len - extoff); + /* + * (protoff == skb->len) mean that the packet doesn't have no data + * except of IPv6 & ext headers. but it's tracked anyway. - YK + */ + if ((protoff < 0) || (protoff > skb->len)) { + pr_debug("ip6_conntrack_core: can't find proto in pkt\n"); + return -NF_ACCEPT; + } + + *dataoff = protoff; + *protonum = pnum; + return NF_ACCEPT; +} + +static unsigned int ipv6_confirm(unsigned int hooknum, + struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + int (*okfn)(struct sk_buff *)) +{ + struct nf_conn *ct; + const struct nf_conn_help *help; + const struct nf_conntrack_helper *helper; + enum ip_conntrack_info ctinfo; + unsigned int ret, protoff; + unsigned int extoff = (u8 *)(ipv6_hdr(skb) + 1) - skb->data; + unsigned char pnum = ipv6_hdr(skb)->nexthdr; + + + /* This is where we call the helper: as the packet goes out. */ + ct = nf_ct_get(skb, &ctinfo); + if (!ct || ctinfo == IP_CT_RELATED_REPLY) + goto out; + + help = nfct_help(ct); + if (!help) + goto out; + /* rcu_read_lock()ed by nf_hook_slow */ + helper = rcu_dereference(help->helper); + if (!helper) + goto out; + + protoff = nf_ct_ipv6_skip_exthdr(skb, extoff, &pnum, + skb->len - extoff); + if (protoff > skb->len || pnum == NEXTHDR_FRAGMENT) { + pr_debug("proto header not found\n"); + return NF_ACCEPT; + } + + ret = helper->help(skb, protoff, ct, ctinfo); + if (ret != NF_ACCEPT) { + nf_log_packet(NFPROTO_IPV6, hooknum, skb, in, out, NULL, + "nf_ct_%s: dropping packet", helper->name); + return ret; + } +out: + /* We've seen it coming out the other side: confirm it */ + return nf_conntrack_confirm(skb); +} + +static unsigned int __ipv6_conntrack_in(struct net *net, + unsigned int hooknum, + struct sk_buff *skb, + int (*okfn)(struct sk_buff *)) +{ + struct sk_buff *reasm = skb->nfct_reasm; + + /* This packet is fragmented and has reassembled packet. */ + if (reasm) { + /* Reassembled packet isn't parsed yet ? */ + if (!reasm->nfct) { + unsigned int ret; + + ret = nf_conntrack_in(net, PF_INET6, hooknum, reasm); + if (ret != NF_ACCEPT) + return ret; + } + nf_conntrack_get(reasm->nfct); + skb->nfct = reasm->nfct; + skb->nfctinfo = reasm->nfctinfo; + return NF_ACCEPT; + } + + return nf_conntrack_in(net, PF_INET6, hooknum, skb); +} + +static unsigned int ipv6_conntrack_in(unsigned int hooknum, + struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + int (*okfn)(struct sk_buff *)) +{ + return __ipv6_conntrack_in(dev_net(in), hooknum, skb, okfn); +} + +static unsigned int ipv6_conntrack_local(unsigned int hooknum, + struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + int (*okfn)(struct sk_buff *)) +{ + /* root is playing with raw sockets. */ + if (skb->len < sizeof(struct ipv6hdr)) { + if (net_ratelimit()) + pr_notice("ipv6_conntrack_local: packet too short\n"); + return NF_ACCEPT; + } + return __ipv6_conntrack_in(dev_net(out), hooknum, skb, okfn); +} + +static struct nf_hook_ops ipv6_conntrack_ops[] __read_mostly = { + { + .hook = ipv6_conntrack_in, + .owner = THIS_MODULE, + .pf = NFPROTO_IPV6, + .hooknum = NF_INET_PRE_ROUTING, + .priority = NF_IP6_PRI_CONNTRACK, + }, + { + .hook = ipv6_conntrack_local, + .owner = THIS_MODULE, + .pf = NFPROTO_IPV6, + .hooknum = NF_INET_LOCAL_OUT, + .priority = NF_IP6_PRI_CONNTRACK, + }, + { + .hook = ipv6_confirm, + .owner = THIS_MODULE, + .pf = NFPROTO_IPV6, + .hooknum = NF_INET_POST_ROUTING, + .priority = NF_IP6_PRI_LAST, + }, + { + .hook = ipv6_confirm, + .owner = THIS_MODULE, + .pf = NFPROTO_IPV6, + .hooknum = NF_INET_LOCAL_IN, + .priority = NF_IP6_PRI_LAST-1, + }, +}; + +#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) + +#include <linux/netfilter/nfnetlink.h> +#include <linux/netfilter/nfnetlink_conntrack.h> + +static int ipv6_tuple_to_nlattr(struct sk_buff *skb, + const struct nf_conntrack_tuple *tuple) +{ + NLA_PUT(skb, CTA_IP_V6_SRC, sizeof(u_int32_t) * 4, + &tuple->src.u3.ip6); + NLA_PUT(skb, CTA_IP_V6_DST, sizeof(u_int32_t) * 4, + &tuple->dst.u3.ip6); + return 0; + +nla_put_failure: + return -1; +} + +static const struct nla_policy ipv6_nla_policy[CTA_IP_MAX+1] = { + [CTA_IP_V6_SRC] = { .len = sizeof(u_int32_t)*4 }, + [CTA_IP_V6_DST] = { .len = sizeof(u_int32_t)*4 }, +}; + +static int ipv6_nlattr_to_tuple(struct nlattr *tb[], + struct nf_conntrack_tuple *t) +{ + if (!tb[CTA_IP_V6_SRC] || !tb[CTA_IP_V6_DST]) + return -EINVAL; + + memcpy(&t->src.u3.ip6, nla_data(tb[CTA_IP_V6_SRC]), + sizeof(u_int32_t) * 4); + memcpy(&t->dst.u3.ip6, nla_data(tb[CTA_IP_V6_DST]), + sizeof(u_int32_t) * 4); + + return 0; +} + +static int ipv6_nlattr_tuple_size(void) +{ + return nla_policy_len(ipv6_nla_policy, CTA_IP_MAX + 1); +} +#endif + +struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 __read_mostly = { + .l3proto = PF_INET6, + .name = "ipv6", + .pkt_to_tuple = ipv6_pkt_to_tuple, + .invert_tuple = ipv6_invert_tuple, + .print_tuple = ipv6_print_tuple, + .get_l4proto = ipv6_get_l4proto, +#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) + .tuple_to_nlattr = ipv6_tuple_to_nlattr, + .nlattr_tuple_size = ipv6_nlattr_tuple_size, + .nlattr_to_tuple = ipv6_nlattr_to_tuple, + .nla_policy = ipv6_nla_policy, +#endif + .me = THIS_MODULE, +}; + +MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET6)); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Yasuyuki KOZAKAI @USAGI <yasuyuki.kozakai@toshiba.co.jp>"); + +static int __init nf_conntrack_l3proto_ipv6_init(void) +{ + int ret = 0; + + need_conntrack(); + nf_defrag_ipv6_enable(); + + ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp6); + if (ret < 0) { + pr_err("nf_conntrack_ipv6: can't register tcp.\n"); + return ret; + } + + ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp6); + if (ret < 0) { + pr_err("nf_conntrack_ipv6: can't register udp.\n"); + goto cleanup_tcp; + } + + ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmpv6); + if (ret < 0) { + pr_err("nf_conntrack_ipv6: can't register icmpv6.\n"); + goto cleanup_udp; + } + + ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv6); + if (ret < 0) { + pr_err("nf_conntrack_ipv6: can't register ipv6\n"); + goto cleanup_icmpv6; + } + + ret = nf_register_hooks(ipv6_conntrack_ops, + ARRAY_SIZE(ipv6_conntrack_ops)); + if (ret < 0) { + pr_err("nf_conntrack_ipv6: can't register pre-routing defrag " + "hook.\n"); + goto cleanup_ipv6; + } + return ret; + + cleanup_ipv6: + nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv6); + cleanup_icmpv6: + nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmpv6); + cleanup_udp: + nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp6); + cleanup_tcp: + nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp6); + return ret; +} + +static void __exit nf_conntrack_l3proto_ipv6_fini(void) +{ + synchronize_net(); + nf_unregister_hooks(ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops)); + nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv6); + nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmpv6); + nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp6); + nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp6); +} + +module_init(nf_conntrack_l3proto_ipv6_init); +module_exit(nf_conntrack_l3proto_ipv6_fini); |