1 files changed, 575 insertions, 0 deletions

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
new file mode 100644
index 000000000000..e0839eafc3a9
--- /dev/null
+++ b/net/ipv6/exthdrs.c
@@ -0,0 +1,575 @@
+/*
+ *      Extension Header handling for IPv6
+ *      Linux INET6 implementation
+ *
+ *      Authors:
+ *      Pedro Roque             <roque@di.fc.ul.pt>
+ *      Andi Kleen              <ak@muc.de>
+ *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
+ *
+ *      $Id: exthdrs.c,v 1.13 2001/06/19 15:58:56 davem Exp $
+ *
+ *      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.
+ */
+
+/* Changes:
+ *      yoshfuji                : ensure not to overrun while parsing 
+ *                                tlv options.
+ *      Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
+ *      YOSHIFUJI Hideaki @USAGI  Register inbound extension header
+ *                                handlers as inet6_protocol{}.
+ */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/sched.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/in6.h>
+#include <linux/icmpv6.h>
+
+#include <net/sock.h>
+#include <net/snmp.h>
+
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/transp_v6.h>
+#include <net/rawv6.h>
+#include <net/ndisc.h>
+#include <net/ip6_route.h>
+#include <net/addrconf.h>
+
+#include <asm/uaccess.h>
+
+/*
+ *      Parsing tlv encoded headers.
+ *
+ *      Parsing function "func" returns 1, if parsing succeed
+ *      and 0, if it failed.
+ *      It MUST NOT touch skb->h.
+ */
+
+struct tlvtype_proc {
+        int     type;
+        int     (*func)(struct sk_buff *skb, int offset);
+};
+
+/*********************
+  Generic functions
+ *********************/
+
+/* An unknown option is detected, decide what to do */
+
+static int ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
+{
+        switch ((skb->nh.raw[optoff] & 0xC0) >> 6) {
+        case 0: /* ignore */
+                return 1;
+
+        case 1: /* drop packet */
+                break;
+
+        case 3: /* Send ICMP if not a multicast address and drop packet */
+                /* Actually, it is redundant check. icmp_send
+                   will recheck in any case.
+                 */
+                if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr))
+                        break;
+        case 2: /* send ICMP PARM PROB regardless and drop packet */
+                icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
+                return 0;
+        };
+
+        kfree_skb(skb);
+        return 0;
+}
+
+/* Parse tlv encoded option header (hop-by-hop or destination) */
+
+static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff *skb)
+{
+        struct tlvtype_proc *curr;
+        int off = skb->h.raw - skb->nh.raw;
+        int len = ((skb->h.raw[1]+1)<<3);
+
+        if ((skb->h.raw + len) - skb->data > skb_headlen(skb))
+                goto bad;
+
+        off += 2;
+        len -= 2;
+
+        while (len > 0) {
+                int optlen = skb->nh.raw[off+1]+2;
+
+                switch (skb->nh.raw[off]) {
+                case IPV6_TLV_PAD0:
+                        optlen = 1;
+                        break;
+
+                case IPV6_TLV_PADN:
+                        break;
+
+                default: /* Other TLV code so scan list */
+                        if (optlen > len)
+                                goto bad;
+                        for (curr=procs; curr->type >= 0; curr++) {
+                                if (curr->type == skb->nh.raw[off]) {
+                                        /* type specific length/alignment 
+                                           checks will be performed in the 
+                                           func(). */
+                                        if (curr->func(skb, off) == 0)
+                                                return 0;
+                                        break;
+                                }
+                        }
+                        if (curr->type < 0) {
+                                if (ip6_tlvopt_unknown(skb, off) == 0)
+                                        return 0;
+                        }
+                        break;
+                }
+                off += optlen;
+                len -= optlen;
+        }
+        if (len == 0)
+                return 1;
+bad:
+        kfree_skb(skb);
+        return 0;
+}
+
+/*****************************
+  Destination options header.
+ *****************************/
+
+static struct tlvtype_proc tlvprocdestopt_lst[] = {
+        /* No destination options are defined now */
+        {-1,                    NULL}
+};
+
+static int ipv6_destopt_rcv(struct sk_buff **skbp, unsigned int *nhoffp)
+{
+        struct sk_buff *skb = *skbp;
+        struct inet6_skb_parm *opt = IP6CB(skb);
+
+        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))) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+                kfree_skb(skb);
+                return -1;
+        }
+
+        opt->dst1 = skb->h.raw - skb->nh.raw;
+
+        if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
+                skb->h.raw += ((skb->h.raw[1]+1)<<3);
+                *nhoffp = opt->dst1;
+                return 1;
+        }
+
+        IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+        return -1;
+}
+
+static struct inet6_protocol destopt_protocol = {
+        .handler        =       ipv6_destopt_rcv,
+        .flags          =       INET6_PROTO_NOPOLICY,
+};
+
+void __init ipv6_destopt_init(void)
+{
+        if (inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS) < 0)
+                printk(KERN_ERR "ipv6_destopt_init: Could not register protocol\n");
+}
+
+/********************************
+  NONE header. No data in packet.
+ ********************************/
+
+static int ipv6_nodata_rcv(struct sk_buff **skbp, unsigned int *nhoffp)
+{
+        struct sk_buff *skb = *skbp;
+
+        kfree_skb(skb);
+        return 0;
+}
+
+static struct inet6_protocol nodata_protocol = {
+        .handler        =       ipv6_nodata_rcv,
+        .flags          =       INET6_PROTO_NOPOLICY,
+};
+
+void __init ipv6_nodata_init(void)
+{
+        if (inet6_add_protocol(&nodata_protocol, IPPROTO_NONE) < 0)
+                printk(KERN_ERR "ipv6_nodata_init: Could not register protocol\n");
+}
+
+/********************************
+  Routing header.
+ ********************************/
+
+static int ipv6_rthdr_rcv(struct sk_buff **skbp, unsigned int *nhoffp)
+{
+        struct sk_buff *skb = *skbp;
+        struct inet6_skb_parm *opt = IP6CB(skb);
+        struct in6_addr *addr;
+        struct in6_addr daddr;
+        int n, i;
+
+        struct ipv6_rt_hdr *hdr;
+        struct rt0_hdr *rthdr;
+
+        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))) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+                kfree_skb(skb);
+                return -1;
+        }
+
+        hdr = (struct ipv6_rt_hdr *) skb->h.raw;
+
+        if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr) ||
+            skb->pkt_type != PACKET_HOST) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS);
+                kfree_skb(skb);
+                return -1;
+        }
+
+looped_back:
+        if (hdr->segments_left == 0) {
+                opt->srcrt = skb->h.raw - skb->nh.raw;
+                skb->h.raw += (hdr->hdrlen + 1) << 3;
+                opt->dst0 = opt->dst1;
+                opt->dst1 = 0;
+                *nhoffp = (&hdr->nexthdr) - skb->nh.raw;
+                return 1;
+        }
+
+        if (hdr->type != IPV6_SRCRT_TYPE_0) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->type) - skb->nh.raw);
+                return -1;
+        }
+        
+        if (hdr->hdrlen & 0x01) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->hdrlen) - skb->nh.raw);
+                return -1;
+        }
+
+        /*
+         *      This is the routing header forwarding algorithm from
+         *      RFC 2460, page 16.
+         */
+
+        n = hdr->hdrlen >> 1;
+
+        if (hdr->segments_left > n) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->segments_left) - skb->nh.raw);
+                return -1;
+        }
+
+        /* We are about to mangle packet header. Be careful!
+           Do not damage packets queued somewhere.
+         */
+        if (skb_cloned(skb)) {
+                struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
+                kfree_skb(skb);
+                /* the copy is a forwarded packet */
+                if (skb2 == NULL) {
+                        IP6_INC_STATS_BH(IPSTATS_MIB_OUTDISCARDS);      
+                        return -1;
+                }
+                *skbp = skb = skb2;
+                opt = IP6CB(skb2);
+                hdr = (struct ipv6_rt_hdr *) skb2->h.raw;
+        }
+
+        if (skb->ip_summed == CHECKSUM_HW)
+                skb->ip_summed = CHECKSUM_NONE;
+
+        i = n - --hdr->segments_left;
+
+        rthdr = (struct rt0_hdr *) hdr;
+        addr = rthdr->addr;
+        addr += i - 1;
+
+        if (ipv6_addr_is_multicast(addr)) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS);
+                kfree_skb(skb);
+                return -1;
+        }
+
+        ipv6_addr_copy(&daddr, addr);
+        ipv6_addr_copy(addr, &skb->nh.ipv6h->daddr);
+        ipv6_addr_copy(&skb->nh.ipv6h->daddr, &daddr);
+
+        dst_release(xchg(&skb->dst, NULL));
+        ip6_route_input(skb);
+        if (skb->dst->error) {
+                skb_push(skb, skb->data - skb->nh.raw);
+                dst_input(skb);
+                return -1;
+        }
+
+        if (skb->dst->dev->flags&IFF_LOOPBACK) {
+                if (skb->nh.ipv6h->hop_limit <= 1) {
+                        IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+                        icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
+                                    0, skb->dev);
+                        kfree_skb(skb);
+                        return -1;
+                }
+                skb->nh.ipv6h->hop_limit--;
+                goto looped_back;
+        }
+
+        skb_push(skb, skb->data - skb->nh.raw);
+        dst_input(skb);
+        return -1;
+}
+
+static struct inet6_protocol rthdr_protocol = {
+        .handler        =       ipv6_rthdr_rcv,
+        .flags          =       INET6_PROTO_NOPOLICY,
+};
+
+void __init ipv6_rthdr_init(void)
+{
+        if (inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING) < 0)
+                printk(KERN_ERR "ipv6_rthdr_init: Could not register protocol\n");
+};
+
+/*
+   This function inverts received rthdr.
+   NOTE: specs allow to make it automatically only if
+   packet authenticated.
+
+   I will not discuss it here (though, I am really pissed off at
+   this stupid requirement making rthdr idea useless)
+
+   Actually, it creates severe problems  for us.
+   Embryonic requests has no associated sockets,
+   so that user have no control over it and
+   cannot not only to set reply options, but
+   even to know, that someone wants to connect
+   without success. :-(
+
+   For now we need to test the engine, so that I created
+   temporary (or permanent) backdoor.
+   If listening socket set IPV6_RTHDR to 2, then we invert header.
+                                                   --ANK (980729)
+ */
+
+struct ipv6_txoptions *
+ipv6_invert_rthdr(struct sock *sk, struct ipv6_rt_hdr *hdr)
+{
+        /* Received rthdr:
+
+           [ H1 -> H2 -> ... H_prev ]  daddr=ME
+
+           Inverted result:
+           [ H_prev -> ... -> H1 ] daddr =sender
+
+           Note, that IP output engine will rewrite this rthdr
+           by rotating it left by one addr.
+         */
+
+        int n, i;
+        struct rt0_hdr *rthdr = (struct rt0_hdr*)hdr;
+        struct rt0_hdr *irthdr;
+        struct ipv6_txoptions *opt;
+        int hdrlen = ipv6_optlen(hdr);
+
+        if (hdr->segments_left ||
+            hdr->type != IPV6_SRCRT_TYPE_0 ||
+            hdr->hdrlen & 0x01)
+                return NULL;
+
+        n = hdr->hdrlen >> 1;
+        opt = sock_kmalloc(sk, sizeof(*opt) + hdrlen, GFP_ATOMIC);
+        if (opt == NULL)
+                return NULL;
+        memset(opt, 0, sizeof(*opt));
+        opt->tot_len = sizeof(*opt) + hdrlen;
+        opt->srcrt = (void*)(opt+1);
+        opt->opt_nflen = hdrlen;
+
+        memcpy(opt->srcrt, hdr, sizeof(*hdr));
+        irthdr = (struct rt0_hdr*)opt->srcrt;
+        /* Obsolete field, MBZ, when originated by us */
+        irthdr->bitmap = 0;
+        opt->srcrt->segments_left = n;
+        for (i=0; i<n; i++)
+                memcpy(irthdr->addr+i, rthdr->addr+(n-1-i), 16);
+        return opt;
+}
+
+/**********************************
+  Hop-by-hop options.
+ **********************************/
+
+/* Router Alert as of RFC 2711 */
+
+static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
+{
+        if (skb->nh.raw[optoff+1] == 2) {
+                IP6CB(skb)->ra = optoff;
+                return 1;
+        }
+        LIMIT_NETDEBUG(
+                 printk(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n", skb->nh.raw[optoff+1]));
+        kfree_skb(skb);
+        return 0;
+}
+
+/* Jumbo payload */
+
+static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
+{
+        u32 pkt_len;
+
+        if (skb->nh.raw[optoff+1] != 4 || (optoff&3) != 2) {
+                LIMIT_NETDEBUG(
+                         printk(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", skb->nh.raw[optoff+1]));
+                IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+                goto drop;
+        }
+
+        pkt_len = ntohl(*(u32*)(skb->nh.raw+optoff+2));
+        if (pkt_len <= IPV6_MAXPLEN) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
+                return 0;
+        }
+        if (skb->nh.ipv6h->payload_len) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
+                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
+                return 0;
+        }
+
+        if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
+                IP6_INC_STATS_BH(IPSTATS_MIB_INTRUNCATEDPKTS);
+                goto drop;
+        }
+        if (pkt_len + sizeof(struct ipv6hdr) < skb->len) {
+                __pskb_trim(skb, pkt_len + sizeof(struct ipv6hdr));
+                if (skb->ip_summed == CHECKSUM_HW)
+                        skb->ip_summed = CHECKSUM_NONE;
+        }
+        return 1;
+
+drop:
+        kfree_skb(skb);
+        return 0;
+}
+
+static struct tlvtype_proc tlvprochopopt_lst[] = {
+        {
+                .type   = IPV6_TLV_ROUTERALERT,
+                .func   = ipv6_hop_ra,
+        },
+        {
+                .type   = IPV6_TLV_JUMBO,
+                .func   = ipv6_hop_jumbo,
+        },
+        { -1, }
+};
+
+int ipv6_parse_hopopts(struct sk_buff *skb, int nhoff)
+{
+        IP6CB(skb)->hop = sizeof(struct ipv6hdr);
+        if (ip6_parse_tlv(tlvprochopopt_lst, skb))
+                return sizeof(struct ipv6hdr);
+        return -1;
+}
+
+/*
+ *      Creating outbound headers.
+ *
+ *      "build" functions work when skb is filled from head to tail (datagram)
+ *      "push"  functions work when headers are added from tail to head (tcp)
+ *
+ *      In both cases we assume, that caller reserved enough room
+ *      for headers.
+ */
+
+static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
+                            struct ipv6_rt_hdr *opt,
+                            struct in6_addr **addr_p)
+{
+        struct rt0_hdr *phdr, *ihdr;
+        int hops;
+
+        ihdr = (struct rt0_hdr *) opt;
+        
+        phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
+        memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
+
+        hops = ihdr->rt_hdr.hdrlen >> 1;
+
+        if (hops > 1)
+                memcpy(phdr->addr, ihdr->addr + 1,
+                       (hops - 1) * sizeof(struct in6_addr));
+
+        ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
+        *addr_p = ihdr->addr;
+
+        phdr->rt_hdr.nexthdr = *proto;
+        *proto = NEXTHDR_ROUTING;
+}
+
+static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
+{
+        struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
+
+        memcpy(h, opt, ipv6_optlen(opt));
+        h->nexthdr = *proto;
+        *proto = type;
+}
+
+void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
+                          u8 *proto,
+                          struct in6_addr **daddr)
+{
+        if (opt->srcrt)
+                ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
+        if (opt->dst0opt)
+                ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
+        if (opt->hopopt)
+                ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
+}
+
+void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
+{
+        if (opt->dst1opt)
+                ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
+}
+
+struct ipv6_txoptions *
+ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
+{
+        struct ipv6_txoptions *opt2;
+
+        opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
+        if (opt2) {
+                long dif = (char*)opt2 - (char*)opt;
+                memcpy(opt2, opt, opt->tot_len);
+                if (opt2->hopopt)
+                        *((char**)&opt2->hopopt) += dif;
+                if (opt2->dst0opt)
+                        *((char**)&opt2->dst0opt) += dif;
+                if (opt2->dst1opt)
+                        *((char**)&opt2->dst1opt) += dif;
+                if (opt2->srcrt)
+                        *((char**)&opt2->srcrt) += dif;
+        }
+        return opt2;
+}