netfilter: nf_conntrack_reasm: properly handle packets fragmented into a single fragment
[safe/jmp/linux-2.6] / net / ipv6 / mip6.c
index 63e548b..f797e8c 100644 (file)
  *     Masahide NAKAMURA @USAGI
  */
 
-#include <linux/config.h>
 #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/rawv6.h>
 #include <net/xfrm.h>
 #include <net/mip6.h>
 
-static xfrm_address_t *mip6_xfrm_addr(struct xfrm_state *x, xfrm_address_t *addr)
+static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
 {
-       return x->coaddr;
+       return (n - len + 16) & 0x7;
 }
 
+static inline void *mip6_padn(__u8 *data, __u8 padlen)
+{
+       if (!data)
+               return NULL;
+       if (padlen == 1) {
+               data[0] = IPV6_TLV_PAD0;
+       } else if (padlen > 1) {
+               data[0] = IPV6_TLV_PADN;
+               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, u8 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;
+}
+
+static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
+{
+       struct ip6_mh *mh;
+
+       if (!pskb_may_pull(skb, (skb_transport_offset(skb)) + 8) ||
+           !pskb_may_pull(skb, (skb_transport_offset(skb) +
+                                ((skb_transport_header(skb)[1] + 1) << 3))))
+               return -1;
+
+       mh = (struct ip6_mh *)skb_transport_header(skb);
+
+       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_network_header(skb)));
+               return -1;
+       }
+
+       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_network_header(skb)));
+               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(mip6_report_rl.lock)
+};
+
+static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+       struct ipv6hdr *iph = ipv6_hdr(skb);
+       struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
+       int err = destopt->nexthdr;
+
+       spin_lock(&x->lock);
+       if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
+           !ipv6_addr_any((struct in6_addr *)x->coaddr))
+               err = -ENOENT;
+       spin_unlock(&x->lock);
+
+       return err;
+}
+
+/* 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;
+
+       skb_push(skb, -skb_network_offset(skb));
+       iph = ipv6_hdr(skb);
+
+       nexthdr = *skb_mac_header(skb);
+       *skb_mac_header(skb) = IPPROTO_DSTOPTS;
+
+       dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
+       dstopt->nexthdr = nexthdr;
+
+       hao = mip6_padn((char *)(dstopt + 1),
+                       calc_padlen(sizeof(*dstopt), 6));
+
+       hao->type = IPV6_TLV_HAO;
+       BUILD_BUG_ON(sizeof(*hao) != 18);
+       hao->length = sizeof(*hao) - 2;
+
+       len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
+
+       memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
+       spin_lock_bh(&x->lock);
+       memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
+       spin_unlock_bh(&x->lock);
+
+       WARN_ON(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 net *net = xs_net(x);
+       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_network_header(skb) + offset);
+       }
+
+       skb_get_timestamp(skb, &stamp);
+
+       if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr,
+                                 hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
+                                 opt->iif))
+               goto out;
+
+       memset(&sel, 0, sizeof(sel));
+       memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
+              sizeof(sel.daddr));
+       sel.prefixlen_d = 128;
+       memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->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(net, 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 *)(ipv6_hdr(skb) + 1);
+       const unsigned char *nh = skb_network_header(skb);
+       unsigned int packet_len = skb->tail - skb->network_header;
+       int found_rhdr = 0;
+
+       *nexthdr = &ipv6_hdr(skb)->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 *)(nh + 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", __func__,
+                      x->id.spi);
+               return -EINVAL;
+       }
+       if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
+               printk(KERN_INFO "%s: state's mode is not %u: %u\n",
+                      __func__, 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);
+       WARN_ON(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 const struct xfrm_type mip6_destopt_type =
+{
+       .description    = "MIP6DESTOPT",
+       .owner          = THIS_MODULE,
+       .proto          = IPPROTO_DSTOPTS,
+       .flags          = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
+       .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,
+};
+
 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
 {
        struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
+       int err = rt2->rt_hdr.nexthdr;
 
+       spin_lock(&x->lock);
        if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) &&
            !ipv6_addr_any((struct in6_addr *)x->coaddr))
-               return -ENOENT;
+               err = -ENOENT;
+       spin_unlock(&x->lock);
 
-       return rt2->rt_hdr.nexthdr;
+       return err;
 }
 
 /* Routing Header type 2 is inserted.
@@ -55,23 +368,25 @@ static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
        struct rt2_hdr *rt2;
        u8 nexthdr;
 
-       iph = (struct ipv6hdr *)skb->data;
-       iph->payload_len = htons(skb->len - sizeof(*iph));
+       skb_push(skb, -skb_network_offset(skb));
+       iph = ipv6_hdr(skb);
 
-       nexthdr = *skb->nh.raw;
-       *skb->nh.raw = IPPROTO_ROUTING;
+       nexthdr = *skb_mac_header(skb);
+       *skb_mac_header(skb) = IPPROTO_ROUTING;
 
-       rt2 = (struct rt2_hdr *)skb->h.raw;
+       rt2 = (struct rt2_hdr *)skb_transport_header(skb);
        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);
+       WARN_ON(rt2->rt_hdr.hdrlen != 2);
 
        memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
+       spin_lock_bh(&x->lock);
        memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
+       spin_unlock_bh(&x->lock);
 
        return 0;
 }
@@ -80,11 +395,13 @@ 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;
+       struct ipv6_opt_hdr *exthdr =
+                                  (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
+       const unsigned char *nh = skb_network_header(skb);
+       unsigned int packet_len = skb->tail - skb->network_header;
        int found_rhdr = 0;
 
-       *nexthdr = &skb->nh.ipv6h->nexthdr;
+       *nexthdr = &ipv6_hdr(skb)->nexthdr;
 
        while (offset + 1 <= packet_len) {
 
@@ -94,7 +411,7 @@ static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
                case NEXTHDR_ROUTING:
                        if (offset + 3 <= packet_len) {
                                struct ipv6_rt_hdr *rt;
-                               rt = (struct ipv6_rt_hdr *)(skb->nh.raw + offset);
+                               rt = (struct ipv6_rt_hdr *)(nh + offset);
                                if (rt->type != 0)
                                        return offset;
                        }
@@ -114,7 +431,7 @@ static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
 
                offset += ipv6_optlen(exthdr);
                *nexthdr = &exthdr->nexthdr;
-               exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
+               exthdr = (struct ipv6_opt_hdr *)(nh + offset);
        }
 
        return offset;
@@ -123,13 +440,13 @@ static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
 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__,
+               printk(KERN_INFO "%s: spi is not 0: %u\n", __func__,
                       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);
+                      __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
                return -EINVAL;
        }
 
@@ -146,36 +463,60 @@ static void mip6_rthdr_destroy(struct xfrm_state *x)
 {
 }
 
-static struct xfrm_type mip6_rthdr_type =
+static const struct xfrm_type mip6_rthdr_type =
 {
        .description    = "MIP6RT",
        .owner          = THIS_MODULE,
        .proto          = IPPROTO_ROUTING,
-       .flags          = XFRM_TYPE_NON_FRAGMENT,
+       .flags          = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR,
        .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)
+static 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", __func__);
+               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__);
+               printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __func__);
                goto mip6_rthdr_xfrm_fail;
        }
+       if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
+               printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __func__);
+               goto mip6_rawv6_mh_fail;
+       }
+
+
        return 0;
 
+ mip6_rawv6_mh_fail:
+       xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
  mip6_rthdr_xfrm_fail:
+       xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
+ mip6_destopt_xfrm_fail:
        return -EAGAIN;
 }
 
-void __exit mip6_fini(void)
+static void __exit mip6_fini(void)
 {
+       if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
+               printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __func__);
        if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
-               printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__);
+               printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __func__);
+       if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
+               printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __func__);
 }
+
+module_init(mip6_init);
+module_exit(mip6_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
+MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);