/* * Copyright (C)2003-2006 Helsinki University of Technology * Copyright (C)2003-2006 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 as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /* * Authors: * Noriaki TAKAMIYA @USAGI * Masahide NAKAMURA @USAGI */ #include <linux/module.h> #include <linux/skbuff.h> #include <linux/time.h> #include <linux/ipv6.h> #include <linux/icmpv6.h> #include <net/sock.h> #include <net/ipv6.h> #include <net/ip6_checksum.h> #include <net/xfrm.h> #include <net/mip6.h> static xfrm_address_t *mip6_xfrm_addr(struct xfrm_state *x, xfrm_address_t *addr) { return x->coaddr; } static inline unsigned int calc_padlen(unsigned int len, unsigned int n) { return (n - len + 16) & 0x7; } static inline void *mip6_padn(__u8 *data, __u8 padlen) { if (!data) return NULL; if (padlen == 1) { data[0] = MIP6_OPT_PAD_1; } else if (padlen > 1) { data[0] = MIP6_OPT_PAD_N; data[1] = padlen - 2; if (padlen > 2) memset(data+2, 0, data[1]); } return data + padlen; } static inline void mip6_param_prob(struct sk_buff *skb, int code, int pos) { icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev); } static int mip6_mh_len(int type) { int len = 0; switch (type) { case IP6_MH_TYPE_BRR: len = 0; break; case IP6_MH_TYPE_HOTI: case IP6_MH_TYPE_COTI: case IP6_MH_TYPE_BU: case IP6_MH_TYPE_BACK: len = 1; break; case IP6_MH_TYPE_HOT: case IP6_MH_TYPE_COT: case IP6_MH_TYPE_BERROR: len = 2; break; } return len; } int mip6_mh_filter(struct sock *sk, struct sk_buff *skb) { struct ip6_mh *mh; int mhlen; if (!pskb_may_pull(skb, (skb->h.raw - skb->data) + 8) || !pskb_may_pull(skb, (skb->h.raw - skb->data) + ((skb->h.raw[1] + 1) << 3))) return -1; mh = (struct ip6_mh *)skb->h.raw; if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) { LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n", mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type)); mip6_param_prob(skb, 0, (&mh->ip6mh_hdrlen) - skb->nh.raw); return -1; } mhlen = (mh->ip6mh_hdrlen + 1) << 3; if (skb->ip_summed == CHECKSUM_COMPLETE) { skb->ip_summed = CHECKSUM_UNNECESSARY; if (csum_ipv6_magic(&skb->nh.ipv6h->saddr, &skb->nh.ipv6h->daddr, mhlen, IPPROTO_MH, skb->csum)) { LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH hw checksum failed\n"); skb->ip_summed = CHECKSUM_NONE; } } if (skb->ip_summed == CHECKSUM_NONE) { if (csum_ipv6_magic(&skb->nh.ipv6h->saddr, &skb->nh.ipv6h->daddr, mhlen, IPPROTO_MH, skb_checksum(skb, 0, mhlen, 0))) { LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH checksum failed " "[" NIP6_FMT " > " NIP6_FMT "]\n", NIP6(skb->nh.ipv6h->saddr), NIP6(skb->nh.ipv6h->daddr)); return -1; } skb->ip_summed = CHECKSUM_UNNECESSARY; } if (mh->ip6mh_proto != IPPROTO_NONE) { LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n", mh->ip6mh_proto); mip6_param_prob(skb, 0, (&mh->ip6mh_proto) - skb->nh.raw); return -1; } return 0; } struct mip6_report_rate_limiter { spinlock_t lock; struct timeval stamp; int iif; struct in6_addr src; struct in6_addr dst; }; static struct mip6_report_rate_limiter mip6_report_rl = { .lock = SPIN_LOCK_UNLOCKED }; static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb) { struct ipv6hdr *iph = skb->nh.ipv6h; struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data; if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) && !ipv6_addr_any((struct in6_addr *)x->coaddr)) return -ENOENT; return destopt->nexthdr; } /* Destination Option Header is inserted. * IP Header's src address is replaced with Home Address Option in * Destination Option Header. */ static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb) { struct ipv6hdr *iph; struct ipv6_destopt_hdr *dstopt; struct ipv6_destopt_hao *hao; u8 nexthdr; int len; iph = (struct ipv6hdr *)skb->data; iph->payload_len = htons(skb->len - sizeof(*iph)); nexthdr = *skb->nh.raw; *skb->nh.raw = IPPROTO_DSTOPTS; dstopt = (struct ipv6_destopt_hdr *)skb->h.raw; dstopt->nexthdr = nexthdr; hao = mip6_padn((char *)(dstopt + 1), calc_padlen(sizeof(*dstopt), 6)); hao->type = IPV6_TLV_HAO; hao->length = sizeof(*hao) - 2; BUG_TRAP(hao->length == 16); len = ((char *)hao - (char *)dstopt) + sizeof(*hao); memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr)); memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr)); BUG_TRAP(len == x->props.header_len); dstopt->hdrlen = (x->props.header_len >> 3) - 1; return 0; } static inline int mip6_report_rl_allow(struct timeval *stamp, struct in6_addr *dst, struct in6_addr *src, int iif) { int allow = 0; spin_lock_bh(&mip6_report_rl.lock); if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec || mip6_report_rl.stamp.tv_usec != stamp->tv_usec || mip6_report_rl.iif != iif || !ipv6_addr_equal(&mip6_report_rl.src, src) || !ipv6_addr_equal(&mip6_report_rl.dst, dst)) { mip6_report_rl.stamp.tv_sec = stamp->tv_sec; mip6_report_rl.stamp.tv_usec = stamp->tv_usec; mip6_report_rl.iif = iif; ipv6_addr_copy(&mip6_report_rl.src, src); ipv6_addr_copy(&mip6_report_rl.dst, dst); allow = 1; } spin_unlock_bh(&mip6_report_rl.lock); return allow; } static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, struct flowi *fl) { struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb; struct ipv6_destopt_hao *hao = NULL; struct xfrm_selector sel; int offset; struct timeval stamp; int err = 0; if (unlikely(fl->proto == IPPROTO_MH && fl->fl_mh_type <= IP6_MH_TYPE_MAX)) goto out; if (likely(opt->dsthao)) { offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); if (likely(offset >= 0)) hao = (struct ipv6_destopt_hao *)(skb->nh.raw + offset); } skb_get_timestamp(skb, &stamp); if (!mip6_report_rl_allow(&stamp, &skb->nh.ipv6h->daddr, hao ? &hao->addr : &skb->nh.ipv6h->saddr, opt->iif)) goto out; memset(&sel, 0, sizeof(sel)); memcpy(&sel.daddr, (xfrm_address_t *)&skb->nh.ipv6h->daddr, sizeof(sel.daddr)); sel.prefixlen_d = 128; memcpy(&sel.saddr, (xfrm_address_t *)&skb->nh.ipv6h->saddr, sizeof(sel.saddr)); sel.prefixlen_s = 128; sel.family = AF_INET6; sel.proto = fl->proto; sel.dport = xfrm_flowi_dport(fl); if (sel.dport) sel.dport_mask = htons(~0); sel.sport = xfrm_flowi_sport(fl); if (sel.sport) sel.sport_mask = htons(~0); sel.ifindex = fl->oif; err = km_report(IPPROTO_DSTOPTS, &sel, (hao ? (xfrm_address_t *)&hao->addr : NULL)); out: return err; } static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb, u8 **nexthdr) { u16 offset = sizeof(struct ipv6hdr); struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1); unsigned int packet_len = skb->tail - skb->nh.raw; int found_rhdr = 0; *nexthdr = &skb->nh.ipv6h->nexthdr; while (offset + 1 <= packet_len) { switch (**nexthdr) { case NEXTHDR_HOP: break; case NEXTHDR_ROUTING: found_rhdr = 1; break; case NEXTHDR_DEST: /* * HAO MUST NOT appear more than once. * XXX: It is better to try to find by the end of * XXX: packet if HAO exists. */ if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n"); return offset; } if (found_rhdr) return offset; break; default: return offset; } offset += ipv6_optlen(exthdr); *nexthdr = &exthdr->nexthdr; exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset); } return offset; } static int mip6_destopt_init_state(struct xfrm_state *x) { if (x->id.spi) { printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__, x->id.spi); return -EINVAL; } if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { printk(KERN_INFO "%s: state's mode is not %u: %u\n", __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); return -EINVAL; } x->props.header_len = sizeof(struct ipv6_destopt_hdr) + calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + sizeof(struct ipv6_destopt_hao); BUG_TRAP(x->props.header_len == 24); return 0; } /* * Do nothing about destroying since it has no specific operation for * destination options header unlike IPsec protocols. */ static void mip6_destopt_destroy(struct xfrm_state *x) { } static struct xfrm_type mip6_destopt_type = { .description = "MIP6DESTOPT", .owner = THIS_MODULE, .proto = IPPROTO_DSTOPTS, .flags = XFRM_TYPE_NON_FRAGMENT, .init_state = mip6_destopt_init_state, .destructor = mip6_destopt_destroy, .input = mip6_destopt_input, .output = mip6_destopt_output, .reject = mip6_destopt_reject, .hdr_offset = mip6_destopt_offset, .local_addr = mip6_xfrm_addr, }; static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb) { struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data; if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) && !ipv6_addr_any((struct in6_addr *)x->coaddr)) return -ENOENT; return rt2->rt_hdr.nexthdr; } /* Routing Header type 2 is inserted. * IP Header's dst address is replaced with Routing Header's Home Address. */ static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb) { struct ipv6hdr *iph; struct rt2_hdr *rt2; u8 nexthdr; iph = (struct ipv6hdr *)skb->data; iph->payload_len = htons(skb->len - sizeof(*iph)); nexthdr = *skb->nh.raw; *skb->nh.raw = IPPROTO_ROUTING; rt2 = (struct rt2_hdr *)skb->h.raw; rt2->rt_hdr.nexthdr = nexthdr; rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1; rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2; rt2->rt_hdr.segments_left = 1; memset(&rt2->reserved, 0, sizeof(rt2->reserved)); BUG_TRAP(rt2->rt_hdr.hdrlen == 2); memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr)); memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr)); return 0; } static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb, u8 **nexthdr) { u16 offset = sizeof(struct ipv6hdr); struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1); unsigned int packet_len = skb->tail - skb->nh.raw; int found_rhdr = 0; *nexthdr = &skb->nh.ipv6h->nexthdr; while (offset + 1 <= packet_len) { switch (**nexthdr) { case NEXTHDR_HOP: break; case NEXTHDR_ROUTING: if (offset + 3 <= packet_len) { struct ipv6_rt_hdr *rt; rt = (struct ipv6_rt_hdr *)(skb->nh.raw + offset); if (rt->type != 0) return offset; } found_rhdr = 1; break; case NEXTHDR_DEST: if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) return offset; if (found_rhdr) return offset; break; default: return offset; } offset += ipv6_optlen(exthdr); *nexthdr = &exthdr->nexthdr; exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset); } return offset; } static int mip6_rthdr_init_state(struct xfrm_state *x) { if (x->id.spi) { printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__, x->id.spi); return -EINVAL; } if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { printk(KERN_INFO "%s: state's mode is not %u: %u\n", __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); return -EINVAL; } x->props.header_len = sizeof(struct rt2_hdr); return 0; } /* * Do nothing about destroying since it has no specific operation for routing * header type 2 unlike IPsec protocols. */ static void mip6_rthdr_destroy(struct xfrm_state *x) { } static struct xfrm_type mip6_rthdr_type = { .description = "MIP6RT", .owner = THIS_MODULE, .proto = IPPROTO_ROUTING, .flags = XFRM_TYPE_NON_FRAGMENT, .init_state = mip6_rthdr_init_state, .destructor = mip6_rthdr_destroy, .input = mip6_rthdr_input, .output = mip6_rthdr_output, .hdr_offset = mip6_rthdr_offset, .remote_addr = mip6_xfrm_addr, }; int __init mip6_init(void) { printk(KERN_INFO "Mobile IPv6\n"); if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __FUNCTION__); goto mip6_destopt_xfrm_fail; } if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) { printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __FUNCTION__); goto mip6_rthdr_xfrm_fail; } return 0; mip6_rthdr_xfrm_fail: xfrm_unregister_type(&mip6_destopt_type, AF_INET6); mip6_destopt_xfrm_fail: return -EAGAIN; } void __exit mip6_fini(void) { if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0) printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__); if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0) printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __FUNCTION__); }